INTERNATIONAL SYMPOSIUM ON MATERIALS ISSUES IN A HYDROGEN ECONOMY

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					                                       INTERNATIONAL
                                        SYMPOSIUM ON
                                  MATERIALS ISSUES IN A
                                   HYDROGEN ECONOMY




                     SCIENTIFIC PROGRAM
                             AND
                       ABSTRACTS BOOK




Endorsed by:                               Supported by:
     American Physical Society               National Science Foundation
     Materials Research Society              U. S. Department of Energy
    American Chemical Society                Dominion Resources
                                             General Motors
                                             Virginia Commonwealth University
                           SYMPOSIUM PROGRAM

                                 Sunday, November 11


 5:00 - 8:00 PM    Registration, Submission of Manuscripts
 6:00 - 8:00 PM    Reception

                                Monday, November 12

                             INAUGURAL SESSION

 9:00 - 9:10 AM    Introductory Remarks
                   Puru Jena, Symposium Chair, Virginia Commonwealth University, USA

 9:10 - 9:20 AM    Welcome Address
                   John B. Fenn, Nobel Laureate, Virginia Commonwealth University, USA


                              SESSION A: Key Note
          Chairman: Constantina Filiou, European Commission, Netherlands

 9:20 - 10:05 AM   “Progress and Challenges of a Hydrogen Economy”
                   Mildred S. Dresselhaus, Massachusetts Institute of Technology, USA

10:05 - 10:35 AM   COFFEE BREAK

10:35 - 11:35 PM   “DOE Hydrogen Program: Production, Delivery and Fuel Cells:
                   Technologies, Challenges, Infrastructure Costs, and Material Needs”
                   Mark D. Paster, Department of Energy, USA

11:35 - 1:30 PM    LUNCH

                            SESSION B: Production I
           Chairman: U. (Balu) Balachandran, Argonne National Lab., USA

 1:30 - 2:00 PM    “Materials Issues for Photoelectrochemical Water Splitting: Chalcopyrite
                   Thin-Films and III-V Nitrides”
                   John A. Turner, National Renewable Energy Laboratory, USA

 2:00 - 2:30 PM    “Hydrogen Production via Water Splitting in Solar Reactors: The
                   Hydrosol Process”
                   Athanasios G. Konstandopoulos, Aerosol & Particle Technology
                   Laboratory, Greece

 2:30 - 3:00 PM    “Development of Photocatalysts for Solar Hydrogen Production”
                   Akihiko Kudo, Tokyo University of Science, Japan


                                            i
3:00 - 3:15 PM      “A Cu/Pt Near-Surface Alloy for Watr-Gas Shift Catalysis Studied by
                    STM, XPS, TPD, and DFT”
                    Ronnie T. Vang, Jan Knudsen, Joachim Schnadt, and Flemming
                    Besenbacher, Interdisciplinary Nanoscience Center, University of Aarhus,
                    Denmark

3:15 - 3:45 PM      COFFEE BREAK


                         Session C: Storage I (Molecular)
                 Chairman: George Thomas, Department of Energy, USA

3:45 - 4:15 PM      “7.5 wt % Hydrogen Storage in Metal Organic Frameworks”
                    Omar M. Yaghi, University of California, USA

4:15 - 4:45 PM      “Henry’s Law and Isoteric Heats in Physisorbents”
                    Channing Ahn, California Institute of Technology, USA

4:45 - 5:15 PM      “Novel Organometallic Fullerene Complexes for Vehicular Hydrogen
                    Storage”
                    Anne C. Dillon, National Renewable Energy Laboratory, USA

5:15 - 5:45 PM      “Engineered Nano-Materials for High Capacity Hydrogen Storage”
                    Taner Yildirim, National Institute of Standards and Technology, USA

5:45 - 6:00 PM      “Design of materials for storing hydrogen in quasi-molecular form”
                    Qiang Sun, Qian Wang, and Puru Jena, Physics Department, Virginia
                    Commonwealth University, USA

6:00 - 8:00 PM      DINNER

8:00 -10:00 PM      Poster Session I



                                 Tuesday, November 13

                               Session D: Fuel Cells I
                 Chairman: Gary Sandrock, Department of Energy, USA

8:30 - 9:00 AM      “Materials Challenges in Proton Exchange Membrane Fuel Cells”
                    Biswajit Choudhury, E. I. du Pont Nemours & Company, USA

9:00 - 9:30 AM      “New PEM Fuel Cell Membranes for Higher Temperature, Drier
                    Operating Conditions Based on the Heteropolyacids”
                    Andrew M. Herring, Colorado School of Mines, USA



                                            ii
 9:30 - 10:00 AM   “Simulation of Reaction and Transport Processes in Fuel Cell Catalysts
                   and Membranes”
                   William A. Goddard, III, California Institute of Technology, USA

10:00 - 10:15 AM   “Alternative Materials to Pd Membranes for Hydrogen Purification”
                   Paul S. Korinko and Thad Adams, Savannah River National Laboratory, USA

10:15 - 10:45 AM   COFFEE BREAK


                     Session E: Storage II (Nano-materials)
                      Chairman: Shengbai Zhang, NREL, USA

10:45 - 11:15 AM   “Carbide-Derived Carbons for Hydrogen Storage”
                   Gleb Yushin, Drexel University, USA

11:15 - 11:45 AM   “Storage of Molecular Hydrogen in Carbon Based Systems”
                   Sa Li, Virginia Commonwealth Univesity, USA

11:45 - 12:15 PM   “Hydride Chemistry in Nanoporous Scaffolds”
                   John J. Vajo, HRL Laboratories, USA

12:15 - 12:30 PM   “High Density H2 Storage on Nanoengineered Scaffolds of Carbon
                   Nanotubes”
                   Carter Kittrell, A.D. Leonard, S. Chakraborty, H. Fan, W.E. Billups,
                   R.H. Hauge, H.K. Schmidt, M. Pasquali, J.M. Tour, Department of
                   Chemistry, Rice University, USA

12:30 - 2:00 PM    LUNCH

                             Session F: Production II
      Chairman: Michelle V. Buchanan, Oak Ridge National Laboratory, USA

 2:00 - 2:30 PM    “H2 Binding and Reactivity on Transition Metal Complexes underlying
                   Biomimetic H2 Production and New Materials for H2 storage”
                   Gregory J. Kubas, Los Alamos National Laboratory, USA

 2:30 - 3:00 PM    “Materials Issues in Photobiological Production”
                   Anastasios Melis, University of California, Berkeley, USA

 3:00 - 3:30 PM    “Hydrogen Production from Hydrocarbons by using Oxygen Permeable
                   Membranes”
                   Hitoshi Takamura, Tohoku University, Japan

 3:30 - 3:45 PM    “Direct Production of Pressurized Hydrogen from Waste Aluminum
                   without Compressor”
                   T. Hiraki, N. Okinaka, H. Uesugi and T. Akiyama, Center for Advanced
                   Research of Energy Conversion Materials, Hokkaido University, Japan,


                                           iii
 3:45 - 5:45 PM    FREE TIME/NETWORKING

        6:00 PM    RECEPTION/DINNER: Jefferson Hotel*
                   *
                   Buses leave OMNI at 6:00 PM for Jefferson Hotel

                   SPEAKER: Ambassador Reno L. Harnish, Principal Deputy Assistant
                   Secretary, Department of State, USA


                               Wednesday, November 14

                   Session G: Storage III (Chemical Hydrides)
              Chairman: Maciej Gutowski, Heriot-Watt University, UK

 8:30 - 9:00 AM    “Indirect, Reversible Hydrogen Storage in Metal Ammine Salts: Recent
                   Progress and Prospects”
                   Claus H. Christensen, Technical University of Denmark, Denmark

 9:00 - 9:30 AM    “Alkali Aminoboranes for Hydrogen Storage”
                   Ping Chen, National University of Singapore, Singapore

 9:30 - 10:00 AM   “Structure and Dynamics of Ammonia Borane”
                   S. Thomas Autrey, Pacific Northwest Laboratory, USA

10:00 - 10:15 AM   “Molecular Simulation of Structural Changes of Ammonia Borane”
                   Gregory K. Schenter, Chris Mundy, Shawn M. Kathmann, Vencislav
                   Parvanov, Nancy J. Hess, Wendy J. Shaw, Herman M. Cho and Thomas
                   Autrey, Pacific Northwest National Laboratory, USA

10:15 - 10:45 AM   COFFEE BREAK

                   Session H: Storage IV (Complex Hydrides)
               Chairman: Karl Johnson, University of Pittsburgh, USA

10:45 - 11:15 AM   “Characterization of Complex Metal Hydrides by High Resolution Solid
                   State NMR”
                   Robert C. Bowman, Jet Propulsion Laboratory, NASA, USA

11:15 - 11:45 AM   “Hydrogenography: A combinatorial thin film approach to identify the
                   thermodynamic properties of metal hydrides”
                   Bernard Dam, Vrije Univerity, Netherlands

11:45 - 12:15 PM   “First-principles engineering of advanced hydrogen storage materials”
                   Vidvuds Ozolins, University of California, Los Angeles, USA

12:15 - 12:30 PM   “Development of Metal Hydrides for High-Pressure MH Tank”
                   T. Matsunaga, T. Shinozawa, K. Washio, D. Mori, M. Ishikiriyama,
                   Higashifuji Technical Center, Toyota Motor Corporation, Japan

                                           iv
12:30 - 2:00 PM      LUNCH

                                 Session I: Fuel Cells II
                    Chairman: Peter Edwards, Oxford University, UK

 2:00 - 2:30 PM      “Materials Challenges in Solid Oxide Fuel Cells”
                     Subhash C. Singhal, Pacific Northwest National Laboratory, USA

 2:30 - 3:00 PM      “The Development of Nano-Composite Electrodes for Natural Gas-
                     Assisted Steam Electrolysis for Hydrogen Production”
                     Raymond J. Gorte, University of Pennsylvania, USA

 3:00 - 3:30 PM      “Near-surface alloys and Core-shell nanocatalysts for reactions involving
                     hydrogen”
                     Manos Mavrikakis, University of Wisconsin, USA

 3:30 - 3:45 PM      “Hybrid Inorganic-Organic Polymer Composites for Polymer-Electrolyte
                     Fuel Cells”
                     Andrea Ambrosini, Cy H. Fujimoto, Christopher J. Cornelius, Sandia
                     National Laboratories, Albuquerque, USA

 3:45 - 4:15 PM      COFFEE BREAK

                      Session J: Storage V (Complexhydrides)
                   Chairman: Vitalij Pecharsky, Ames Laboratory, USA

 4:15 - 4:45 PM      “Reaction Mechanism and Kinetics of Reactive Hydride Composites”
                     Martin Dornheim, GKSS Research Centre Geesthacht, Germany

 4:45 - 5:15 PM      “Single- and Double-Cations Borohydrides for Hydrogen Storage
                     Applications”
                     Shin-ichi Orimo, Tohoku University, Japan

 5:15 - 5:45 PM      “Tetrahydroboranates: The New Hydrogen Storage Materials”
                     Andreas Borgschulte, EMPA Materials Science and Technology,
                     Switzerland

 5:45 - 6:00 PM      “Storage of Compressed Hydrogen in Multi-capillary Arrays”
                     N. K. Zhevago and Dan Eliezer, Ben Gurion University, Israel.

 6:00 - 8:00 PM      DINNER

 8:00 - 10:00 PM     Poster Session II




                                              v
                                  Thursday, November 15

                            Session K: Safety & Education
                   Chairman: B. S. Shivaram, University of Virginia, USA

 8:30 - 9:00 AM       “Structural-Materials Considerations for Hydrogen Gas Containment”
                      Chris San Marchi, Sandia National Laboratory, USA

 9:00 - 9:30 AM       “A National Agenda for Hydrogen Codes and Standards”
                      Chad Blake, National Renewable Energy Laboratory, USA

 9:30 - 10:00 AM      “Educating Key Audiences about Fuel Cell Technologies”
                       Robert Remick, National Renewable Energy Laboratory, USA

10:00 - 10:15 AM      “Hydrogen behavior and coloration of tungsten oxide films prepared by
                      magnetron sputtering and pulsed laser deposition”
                      S. Nagata, A. Inouye, S. Yamamoto, B. Tsuchiya, T. Shikama, Institute
                      for Materials Research, Tohoku University, Japan

10:15 - 10:45 AM      COFFEE BREAK

                                 Session L: Storage –VI
                           Chairman: Ragaiy Zidan, SRNL, USA

10:45 - 11:15 AM      “Hydrogen Storage and Delivery Using Liquid Carriers”
                      Guido Pez, Air Products and Chemicals Inc, USA

11:15 - 11:45 AM      “Hydrogen Storage Materials – Playing the Odds”
                      W.I.F. David, Oxford University, UK

11:45 - 12:15 PM       “Probing Structure, Bonding, and Dynamics in Hydrogen
                      Storage Materials by Neutron-Scattering Techniques”
                      Terrence J. Udovic, NIST Center for Neutron Research, USA

12:15 - 12:30 PM      “Thermodynamics of Doped Complex Metal Hydrides”
                       J. Karl Johnson, Sudhakar V. Alapati, Bing Dai, David S. Sholl,
                      Department of Chemical Engineering, University of Pittsburgh,
                      Pittsburgh, USA

12:30 - 2:30 PM       LUNCH

 2:30 - 4:00 PM        Panel Discussion:

                             Chair: Scott W. Jorgensen, General Motors, USA
                             Richard Chahine, Univ. du Quebec a Trois Rivieres, Canada
                             Jeremy P. Meyers, University of Texas, USA
                             George D. Parks, Conoco-Phillips, USA
                             Astrid A. Pundt, University of Goettingen, Germany
                             Yaroslav Filinchuk, European Synchrotron Radiation Facility
                                             vi
   ABSTRACTS OF
ORAL PRESENTATIONS
                                            O–1




                 Progress and Challenges of a Hydrogen Economy
                                     M. S. Dresselhaus
    Department of Electrical Engineering and Computer Science and Department of Physics
                            Massachusetts Institute of Technology
                                Cambridge, MA 02139, USA



In this overview talk, the grand energy challenges are reviewed succinctly and the elements of
the hydrogen initiative are reviewed with particular emphasis given to hydrogen storage, the
most vexing challenge of the hydrogen initiative. This is followed by a discussion of promising
approaches that have been opened up through nanoscience. Examples will be given of recent
progress that has been made with special attention given to the promise offered by the
nanoworld.
                                               O–2




DOE Hydrogen Program: Production, Delivery, and Fuel Cells: Technologies,
         Challenges, Infrastructure Costs, and Materials Needs

                                        Mark Paster
                Office of Hydrogen, Fuel Cells, and Infrastructure Technologies
              U.S. Department of Energy, Energy Efficiency and Renewable Energy


     Two key goals of U.S. energy policy are energy security and reduced emissions including
green house gas emissions. The use of hydrogen as an energy carrier, particularly in combination
with fuel cell vehicles in the transportation sector, is an approach that can help meet these goals.
In 2003, President Bush announced the Hydrogen Fuel Initiative (HFI) and pledged $1.2B over
five years to hydrogen and fuel cell research and development. In 2007 he announced the
Advanced Energy Initiative (AEI) supporting funding increases over a spectrum of energy
technologies including; biofuels, solar, wind, nuclear, coal with carbon sequestration as well
continued support for the HFI. DOE has worked with public and private organizations to develop
the National Hydrogen Energy Roadmap1 and has developed the DOE Hydrogen Posture Plan1.
These documents describe the research, development, and demonstration steps required to enable
hydrogen to become a major energy carrier. Key challenges include cost effective technology to
store sufficient hydrogen on-board vehicles to provide at least 300 miles driving range, low cost
and durable PEM fuel cells, and lower cost and energy efficient hydrogen production and
delivery technology. Significant progress is being made in all of these areas but considerable
challenges remain.
     Hydrogen can be produced from a variety of domestic resources including; natural gas, coal,
water, wind, solar, nuclear energy and biomass. It can also be produced using a variety of
technologies that result in near-zero greenhouse gas emissions and other emissions including;
coal gasification with carbon sequestration, biomass gasification, reforming of bio-derived
liquids (e.g. ethanol, sugars), electrolysis, high temperature thermochemical water splitting
cycles, biological production and direct photoelectrochemical production. This variety of
potential production pathways from domestic resources is key to energy security. The U.S.
Department of Energy (DOE) is funding research in all these hydrogen production pathways.
     Hydrogen delivery is an essential component of any future hydrogen energy infrastructure.
Hydrogen must be transported from the point of production to the point of use, and handled
within refueling stations or stationary power facilities. There are three potential delivery
pathways: gaseous hydrogen delivery, liquid hydrogen delivery, and novel solid or liquid
hydrogen carriers. The DOE Hydrogen Delivery Program element is a comprehensive effort to
research and develop technology to reduce the cost and improve the energy efficiency of
hydrogen delivery. It includes pipeline research, improved compression technology,
breakthrough liquefaction technology, lower cost off-board storage and extensive analysis of the
delivery options for both the transition and longer term use of hydrogen as a major energy
carrier.
     This presentation will discuss the technologies, challenges, costs, and materials needs for
cost effective and efficient hydrogen production and delivery infrastructure.

1. www.eere.energy.gov/hydrogenandfuelcells
                                              O–3




            Materials Issues for Photoelectrochemical Water Splitting:
                   Chalcopyrite Thin-Films and III-V Nitrides
                                     John A. Turner
               National Renewable Energy Laboratory, Golden, CO USA 80401
                                 E-mail: jturner@nrel.gov


The direct photoelectrochemical (PEC) splitting of water is a one-step process for the production
of H2 using solar irradiation; water is split directly upon illumination. This direct conversion
system utilizes the process where an illuminated semiconductor material immersed in aqueous
solution, is used to decompose water directly. Light is absorbed in the semiconductor and water
is split at the semiconductor surface. The key is to match the light-harvesting properties of the
semiconductor with a catalyst that can efficiently collect the energy and direct it towards the
water splitting reaction. The simplest PEC based direct water splitting system would consist of
an illuminated single gap semiconductor having a bandgap greater than 1.6 electron volts
coupled to a surface catalyst immersed in an aqueous solution.
     To date, no semiconducting material has been discovered that simultaneously meets all the
criteria required for economical hydrogen production via light-driven direct water splitting.
Whilst considerable work has been directed at metal oxides due to their expected stability, little
thought has been given to the requirement that these PEC devices must have the same
fundamental internal quantum efficiency as the commercial high efficiency PV devices.
Chalcopyrite materials in the family of Cu(In,Ga)(SSe) are known to have high PV conversion
efficiencies and can be made with low-cost thin film approaches, making them appealing
candidates for PEC water splitting. CuGaSe2, with an energy gap close to 1.7eV, is at the lower
end of the desired band gap range for water splitting materials but nonetheless of interest. The
III-V nitride materials have shown excellent stability as evidenced by corrosion analysis;
however, they show a significant decrease in overall conversion efficiency as compared to other
non-nitride III-Vs.
     This report will summarize our efforts on these materials and their application to tandem
cells for photoelectrochemical water splitting. Issues relating to metal oxides will also be
discussed.
                                                O–4




           Hydrogen Production via Water Splitting in Solar Reactors:
                            the Hydrosol Process
            Athanasios G. Konstandopoulosa,b,*, C. Sattlerc, P. Stobbed, A.M. Steelee
     a
       Aerosol & Particle Technology Laboratory, CERTH/CPERI, P.O. Box 361, Thermi,
  Thessaloniki 57001, Greece and b Department of Chemical Engineering, Aristotle University,
                           P.O. Box 1517, 54006, Thessaloniki, Greece
         c
           Deutsches Zentrum für Luft- und Raumfahrt e.V. (DLR), Institut für Technische
                    Thermodynamik, Solarforschung, D-51170 Köln, Germany
               d
                 Stobbe Tech Ceramics, Vejlemosevej 60, DK-2840, Holte, Denmark
       e
        Johnson Matthey Technology Centre, Sonning Common, RG4 9NH, Reading, UK
                                  *E-mail: agk@cperi.certh.gr

     The present work reviews recent work in the field of solar thermochemical hydrogen
production via water splitting in monolithic reactors, also known as the Hydrosol process. The
process employs a reactor concept, adapted from the well-known automotive emission control
field, and consists of multi-channel ceramic honeycombs, coated with active water-splitting
materials, that are heated by concentrated solar radiation to the desired temperature. When water
vapor passes through the reactor, the coating material splits the water molecule by “trapping” its
oxygen and leaving in the effluent gas stream pure hydrogen. In a next step, the oxygen
“trapping” material is regenerated, by increasing the amount of solar heat absorbed by the
reactor; hence, a cyclic operation is established. Multi-cyclic solar thermo-chemical splitting of
water was successfully demonstrated on a pilot solar reactor achieving constant hydrogen
production exclusively at the expense of solar energy. The presentation addresses the synthesis
of active water-splitting materials, their deposition upon the ceramic monoliths, the testing of
relevant properties of merit such as the thermomechanical stability and hydrogen yield and
finally the design, simulation operation and performance optimization of structured monolithic
solar hydrogen production reactors.
                                                 O–5




          Development of Photocatalysts for Solar Hydrogen Production
                                      Akihiko KUDO a,b
    a
      Department of Applied Chemistry, Tokyo University of Science, Tokyo,1-3 Kagurazaka,
                             Shinjuku-ku, Tokyo 162-8601 Japan,
b
  Core Research for Evolutional Science and Technology, Japan Science and Technology Agency
             (CREST, JST), 4-1-8 Honcho, Kawaguchi-shi, Saitama 332-001, Japan

The importance of hydrogen energy has recently been re-recognized because of the interest in
clean energy. Hydrogen is mainly produced by steam reforming of hydrocarbons such as
methane in industry. Hydrogen must be produced from water using renewable energy sources
such as solar light, if one considers the energy and environmental issues. Therefore,
photocatalytic water splitting is still a challenging reaction because it is an ultimate solution to
these serious problems. Recently, many new poedered photocatalysts for water splittng have
been developed [1]. For, example, a NiO (0.2 wt %)/NaTaO3:La (2%) photocatalyst with a 4.1-
eV band gap showed high activity for water splitting into H2 and O2 with an apparent quantum
yield of 56% at 270 nm. Overall water splitting under visible light irradiation has been achieved
by construction of a Z-scheme photocatalysis system employing visible-light-driven
photocatalysts for H2 and O2 evolution, and an Fe3+/ Fe2+ redox couple as an electron relay.
Moreover, highly efficient sulfide photocatalysts for production of solar hydrogen was
developed by making solid solutions of ZnS and narrow band gap semiconductors. However,
these photocatalysts are still out of the practical use. It will be an ultimate green chemical
process if solar hydrogen production using the powdered photocatalyst is accomplised. The
possibility of the powdered photocatalysts for that purpose is discussed.

[1] A. Kudo, H. Kato, and I. Tsuji, Chem. Lett., 2004, 33, 1534.
                                             O–6




 A Cu/Pt Near-Surface Alloy for Water-Gas Shift Catalysis Studied by STM,
                           XPS, TPD, and DFT
         Ronnie T. Vang, Jan Knudsen, Joachim Schnadt, and Flemming Besenbacher
  Interdisciplinary Nanoscience Center (iNANO) and Department of Physics and Astronomy,
                               University of Aarhus, Denmark.
                                   E-mail: rtv@inano.dk

     Hydrogen produced from steam reforming of fossil fuels accounts for the majority of the
present hydrogen consumption and is expected to play a key role for the short term introduction
of a hydrogen-based economy. The water-gas shift (WGS) reaction, in which carbon monoxide
(CO) and water (H2O) react to form carbon dioxide (CO2) and hydrogen (H2), is a crucial step in
the production of clean (CO free) hydrogen, and as such it is important to optimize the WGS
process to achieve an overall effective hydrogen production. In particular, efficient WGS
catalysis is needed for onboard reforming of, e.g., methanol in vehicles powered by low
temperature fuel cells. Clean hydrogen (CO free) is needed to run the low temperature fuel cells,
and at the same time the weight of the fueling system, including the WGS reactor, should be as
low as possible to preserve fuel efficiency.
     In this study we use a combination of scanning tunneling microscopy (STM), x-ray
photoelectron spectroscopy (XPS), temperature programmed desorption (TPD), and density
functional theory (DFT) to study a bimetallic Cu/Pt model catalyst for the WGS reaction.1 From
STM, XPS, and DFT we find that when Cu is evaporated onto Pt(111) at high temperature (800
K) a thermodynamically stable surface alloy is formed. The topmost atomic layer in this surface
alloy consists purely of Pt, and the Cu atoms are embedded in the subsurface layer with the
highest Cu concentration in the first subsurface layer. The TPD measurements show that the
subsurface Cu atoms weaken the binding of CO to the topmost Pt layer, thus minimizing the risk
of CO poisoning of the catalyst. This observation is confirmed by the DFT calculations.
Furthermore, the calculations show that the Cu/Pt(111) surface alloy effectively activates water,
which is the rate limiting step in the WGS reaction on several metal surfaces, while at the same
binding the reaction products (CO) and reaction intermediates (formate) weakly, whereby
poisoning of the catalyst surface is reduced. The results thus show that the bimetallic Cu/Pt
catalyst is a promising candidate for an improved WGS catalyst.


   1. J. Knudsen, A. U. Nilekar, R. T. Vang, J. Schnadt, E. L. Kunkes, J. A. Dumesic, M.
      Mavrikakis and F. Besenbacher, J. Am. Chem. Soc., 2007, 129, 6485-6490.
                                              O–7




            7.5 wt% Hydrogen Storage in Metal Organic Frameworks
                                        Omar M. Yaghi
 Department of Chemistry and Biochemistry, University of California, Los Angeles, Center for
 Reticular Materials Research at California NanoSystems Institute, 607 Charles E. Young Drive
                              East, Los Angeles, CA 90095-1569.
                                 E-mail: yaghi@chem.ucla.edu


The discovery of H2 adsorption in porous metal-organic frameworks (MOFs) and subsequent
related studies have firmly established these materials as interesting candidates for H2 storage
applications, due to the availability of a large numbers of well-characterized MOFs and the
flexibility with which their organic and inorganic components can be varied. We have delineated
numerous strategies that can be used in MOF chemistry for achieving the targets for on-board H2
storage systems set by the US Department of Energy (DOE) for use of H2 as a fuel [1].
     Recently, we showed that MOF-177 can store 7.5 wt% H2 with a volumetric capacity of 32 g
  -1
L at 77 K and 70 bar [2]. This is exciting as the MOF exhibits the highest H2 uptake of any
porous materials and clearly shows that in principle the DOE targets can be achieved at 77 K.
However it is important to establish a benchmark material for researchers in the field of H2
storage because the field has often suffered from reports of high H2 uptake which were later
found to be erroneous.
     This presentation will (i) show that the saturation uptake of H2 in MOFs correlates well with
surface area and that viable volumetric densities in highly porous structures can indeed be
achieved, (ii) show independent verification of H2 uptake data in MOF-177 [3], (iii) discuss the
differences between absolute versus excess uptake capacities, and (iv) outline future prospects
for room temperature H2 uptake.


[1] Rowsell, J. L. C.; Yaghi, O. M. Angew. Chem. Int. Ed., 2005, 44, 4670.
[2] Wong-Foy, A. G.; Matzger, A. J.; Yaghi, O. M. J. Am. Chem. Soc. 2006, 128, 3494.
[3] Furukawa, H.; Miller, M. A.; Yaghi, O. M. J. Mater. Chem. 2007, 17, 3197.
                                               O–8




                  Henry's Law and Isosteric Heats in Physisorbents
                              Channing Ahn and Houria Kabbour
                        California Institute of Technology, Pasadena, CA
                                    E-mail: cca@caltech.edu


Effective physisorbents require both high surface area and high adsorption enthalpies. There are
                                                                                        s
two enthalpies that can be determined readily from sorption isotherms. The Henry' law region
at low pressures yields the differential enthalpy at zero coverage and provides a single
convenient enthalpy value. The enthalpy can also be determined from isosteric heat
measurements from the same isotherm data, provided that the data is taken over a high-pressure
range that includes the surface excess maximum. While the two quantities are similar at low
                                                            s
coverage, and while the direct measurement of the Henry' law value is the easiest to determine,
the isosteric heat yields the most useful data as it plots enthalpy as a function of hydrogen
loading. Ideally, the sorption heats are constant as a function of ad-atom/molecule coverage
density. This is typically not the case due to sorption site heterogeneities that are typical of real
surfaces, and due to hydrogen-hydrogen interactions that occur at higher pressures. Examples of
systems with initially high sorption enthalpies are coordinatively unsaturated metal centers as
found in framework structures like Prussian blues and some metal organic frameworks. After
the initial high enthalpy site(s) adsorb hydrogen, only surfaces with weaker adsorption enthalpies
are then available. We will discuss this behavior in a MOF-74 structure which shows an initially
high isosteric enthalpy of 8.8kJ/mole, but which drops to half of that value within 2wt% of
gravimetric uptake.
                                              O–9




 Novel Organometallic Fullerene Complexes for Vehicular Hydrogen Storage

  A.C. Dillon, E. Whitney, C. Engtrakul, C. J. Curtis, K.J. O’Neill, P.A. Parilla, L.J. Simpson,
                      M.J. Heben, Y. Zhao, Y-H. Kim and S. B. Zhang
      National Renewable Energy Laboratory, 1617 Cole Blvd, Golden, CO 80401, USA

     Theoretical studies have predicted that scandium may bind to the twelve five-membered
rings in C60. It would then be possible to stabilize four dihydrogen ligands (H2) on each Sc atom
with a binding energy of ~ 30 kJ/mol, with a ~7.0 wt% reversible hydrogen capacity(1), ideal
for vehicular hydrogen storage. However, wet chemical synthesis of the calculated η5-
coordinated fullerene complex is unprecedented. The chemistry of C60 is generally olefinic (i.e.,
η2-coordination, in which the metal is coordinated to two carbon atoms contributing two
electrons to the bonding). Another theoretical investigation has suggested that the lithium
fulleride, Li12C60, may be promising for onboard vehicular hydrogen storage applications(2). In
this study, the Li atoms are centered over each of the twelve five-membered rings in C60, and
hydrogen is stored with a capacity of ~ 9 wt% and a reversible binding energy of ~ 7 kJ/mol.
However, again experimental challenges in synthesizing this molecule are anticipated as Li
generally clusters in the octahedral voids of the fcc lattice of C60 crystals.
     Recently we have probed new synthetic techniques in order to coordinate C60 with either Fe,
Sc, Cr, Co or Li. The new compounds were characterized with 13C solid-state nuclear magnetic
resonance, Raman spectroscopy, electron paramagnetic spin resonance, transmission electron
microscopy and nanoprobe energy dispersive x-ray spectroscopy. All of the structures were
found to have unique binding sites for hydrogen employing the technique of temperature
programmed desorption. Furthermore, the Fe(C60) complex has a reversible hydrogen storage
capacity of 0.5 wt% at 77 K with an H2 overpressure of 2 bar (with unaltered C60 having an
undetectable hydrogen capacity). The extensive characterization techniques indicate that C60-Fe-
C60-Fe-C60-chain structures of an undetermined length are formed and that η5-coordination is
demonstrated. Interestingly, the specific surface area of the Fe(C60) compound is only ~ 50 m2/g
indicating that a mechanism other than surface physisorption may be occurring. A Li12C60
compound has also been synthesized. In good agreement with the theoretical studies, the
experimentally determined hydrogen binding energy for the compound is approximately 7
kJ/mol. However, the reversible capacity at 77 K and 2 bar is only ~ 0.3 wt%. The difference
between the experimental and theoretical capacity is attributed to significant differences in
structure. Collectively however, these results suggest that synthesis of organometallic fullerene
complexes should be further explored for vehicular hydrogen storage applications.

   1. Y. Zhao, Y.-H. Kim, A. C. Dillon, M. J. Heben, S. B. Zhang, Physical Review Letters 94,
      155504 (2005).
   2. Q. Sun, P. Jena, Q. Wang, M. Marquez, JACS 128, 9741 (2006)
                                             O – 10




           Engineered Nano-Materials for High Capacity Hydrogen Storage
                                             T. Yildirim1,2
       1
           National Institute of Standards and Technology, NCNR, Gaithersburg, MD 20899
               2
                 Department of Materials Science and Eng., University of Pennsylvania,
                                        Philadelphia, PA 19104


Developing safe, cost-effective, and practical means of storing hydrogen is crucial for the
advancement of hydrogen and fuel-cell technologies. The current state-of-the-art is at an impasse
in providing any materials that meet a storage capacity of 6wt% or more required for practical
applications. The main obstacles in hydrogen storage are slow kinetics, poor reversibility and
high dehydrogenation temperatures for the chemical hydrides, and very low desorption
temperatures/energies for the physisorption materials such as activated carbon. In this talk, we
first discuss several neutron experiments for hydrogen absorption properties of several novel
high-surface nano-porous materials such as metal-organic-frameworks (MOFs) and zealic
imidazolate frameworks (ZIFs). Even though these new materials have large surface area to
absorb up to 10 wt% hydrogen molecules at low temperature, the interaction is weak and
therefore at room temperature there is no absorption. In the second part of the talk, we will
propose a new “nano-guest host concept” to increase the H2 binding energy in these light-weight
high-surface area materials such as MOFs and ZIFs. From accurate quantum mechanical
calculations, we show that ligh transition metals (TM) such as a Ti-atom affixed to several
nanostructures such as nanotubes/C60 and small organic molecules (C2H4) strongly bind up to
five hydrogen molecules. The first H2 adsorption is dissociative with ~0.25 eV energy barrier
while other adsorptions are molecular with significantly elongated H-H bonds. The metal-
hydrogen interaction is found to be very unique, lying between chemi and physisorption, with a
binding energy of 0.4 eV compatible with room temperature desorption and absorption.
Simulations at high temperature indicate that such hybrid systems of transition metals affixed to
nanostructures are quite stable and exhibit associative desorption upon heating, a requirement for
reversible storage. These results not only advance our fundamental understanding of dissociative
adsorption of hydrogen on transition metals in nano-structures but also suggest new routes to
better storage and catalyst materials.

(a)                       (b)




                                                    Results of modeling studies indicate that
                                                    attaching titanium atoms (blue) to the ends of
                                                    an ethylene molecule (yellow-green) will
                                                    result in a capsule-shaped complex that
                                                    absorbs 10 hydrogen molecules (red),
                                                    (14wt% capacity). Phys. Rev. Lett. 97,
                                                    226102 (2006)
                                               O – 11




            Design of materials for storing hydrogen in quasi-molecular form
                           Qiang Sun 1, 2, Qian Wang 1, and Puru Jena 1
          1
            Physics Department, Virginia Commonwealth University, Richmond, VA 23284
 2
   Department of Advanced Materials and Nanotechnology, Peking University, Beijing 1000871, China


 Synthesis of materials capable of storing hydrogen with large gravimetric and volumetric density
 and operating at near ambient thermodynamic conditions is critical to the success of a hydrogen
 economy. Carbon based materials due to their light weight have been regarded as possible
 candidates for hydrogen storage. Recent works suggested that carbon nanostructures such as
 fullerenes, organic molecules, and nanotubes suitably functionalized with transition metal atoms
 can meet the hydrogen storage requirements. These materials store hydrogen in quasi-molecular
 form with binding energies intermediate between physisorbed and chemisorbed states. However,
 the stability of these materials has been a problem to deal with since transition metal atoms have
 a tendency to cluster and hence adversely affect the hydrogen storage capability. We have
 considered two classes of materials where this limitation can be avoided. These include coating
 of carbon nanostructures with Li where the low cohesive energy of Li does not induce clustering.
 Unfortunately, the binding energy of hydrogen on Li coated fullerenes is very small and
 cryogenic temperatures are needed. A second class of materials where metal atoms can be
 prevented from clustering and yet store hydrogen with a binding energy around 0.5 eV/H2
 molcule involves silsesquioxanes (SQ) nano complex [RSiO3/2]n with R= -C5H5. Grafting of
 cyclopentadienyl on this complex totally changes its electronic structure and chemistry.
 Cyclopentadienyl becomes a reactive site where a transition-metal atom (e.g., Sc) can be doped
 and the metal atoms serve as an effective adsorption site for hydrogen molecules. Because of the
 strong bonding of transition metal atoms to the SQ complex, they are prevented from clustering.
 This nano complex has the following advantages: (1) Storage capacity in the fully grafted case is
 5 wt% where hydrogen is bound quasi-molecularly with a binding energy of about 0.6 eV /H2
 molecule. (2) The structure of SQ itself is stable, and the synthesis is very flexible. These results
 are obtained using density functional theory and generalized gradient approximation for
 exchange and correlation. We hope that our prediction of the effectiveness of functionalized SQ
 complex as a hydrogen storage material will encourage experimental investigation.


1. Q. Sun, Q. Wang , and P. Jena, Nano Letters 5 (2005) 1273
2. Q. Sun , Q. Wang, P. Jena, and Y. Kawazoe, J. Am. Chem. Soc.127, (2005)14582
3. Q. Sun, P. Jena, Q. Wang, and M. Marquez, J. Am. Chem. Soc. 128, (2006) 9742
4. Q. Sun, Q. Wang, P. Jena, B. V. Reddy, and M. Marquez , Chem. Mater., 19, 3074 ( 2007)
                                                 O – 12




           Material Challenges in Proton Exchange Membrane Fuel Cells
                  B. Choudhury, G. Escobedo, K. Barton, D. Curtin, R. Perry
   E.I. du Pont Nemours & Company, DuPont Fuel Cells, Chestnut Run Plaza, Wilmington, DE
                                         19805


       Fuel cells are generally considered as a clean, efficient and silent technology that can
  produce electricity and heat from fossil fuels, biofuels as well as hydrogen produced from
  renewable energy sources such as wind energy and solar energy. The expectations held since mid
  1990s with respect to their commercial introduction in transport as early as 2003 and stationary
  applications by 2001 have yet to be realized. The main hurdles preventing commercial
  introduction continue to be high cost, lack of durability, high system complexity and a lack of
  fuel infrastructure.
       Understanding and improving the chemical and mechanical durability of PEM fuel cells are
  key subjects of research and development in industrial, government and academic laboratories
  worldwide. Degradation of component materials, such as the membrane and membrane electrode
  assembly (MEA) under the demanding operational conditions in the PEM fuel cells is
  responsible for many failures observed in system tests.
     DuPont has made significant progress in the development and improvement of
perfluorosulfonic acid membranes, such as Nafion®, and MEAs for hydrogen and reformed
hydrogen fuel cell applications. This talk will focus on the systematic approach taken by DuPont,
and the progress in the development of durable membrane and MEAs to meet the lifetime
objectives of the Fuel Cell industry.
                                                 O – 13




 New PEM Fuel Cell Membranes For Higher Temperature, Drier Operating
              Conditions Based On The Heteropolyacids.
          Andrew M. Herring,1 James L. Horan,2 Niccolo V. Aieta,1 Mei-Chen Kuo,1
                                     and Steven F. Dec.2
                          1
                            Department of Chemical Engineering, and
  2
    Department of Chemistry and Geochemistry, Colorado School of Mines, Golden, CO 80401,
                                            USA.
                                  Email: aherring@mines.edu


     State of the art proton exchange membrane (PEM) fuel cells currently use perfluorosulfonic
acid (PFSA) ionomers. PFSA PEMs are limited to operating temperatures of 80°C or less and
require high relative humidity foe adequate proton conduction. For automotive applications it is
desirable to operate the fuel cell at a temperature of at least 120°C and low humidity to enable
the use of existing radiator technology and to eliminate the parasitic loads and system
complications associated with externally humidifying the gas streams. For stationary
applications PEM fuel cells operating at elevated temperature would allow the use of cheaper H2
containing larger amounts of CO and facilitate combined heat and power applications. At the
same time new electrolytes must also display i) adequate proton conductivity at -20°C for cold
start-up, ii) sufficient oxidative stability for long life, iii) impermeability of reactant gases for
minimal crossover, and iv) suitable mechanical attributes. To date, there have been many
attempts to develop a PEM for use under the conditions of elevated temperature and low RH, but
none of these have sufficient proton conductivity and durability in a fuel cell environment to
represent a practical solution.
     The heteropoly acids (HPA) represent a synthetically versatile inorganic super acid
functionality that has very high proton conductivity at room temperature, 0.2 S cm-1, and can be
readily incorporated into hybrid organic/inorganic composite materials. Whilst many reports
have shown that proton conductivity in the commercially available HPA is dependant on water,
research at CSM has demonstrated HPA as useful proton conductors in working fuel cells at
temperatures as high as 215°C, offering high proton self diffusion coefficients that peak at
temperatures as high as 130°C and activation energy values, Ea, as low as 6 KJ Mol-1. We are
the first group in the world to report a complete polarization curve for a membrane in which an
HPA in the solid state is the only proton conductor. We are currently working on two
approaches. In one we synthesize hybrid HPA monomers that can be co-polymerized into stand
alone proton conducting materials. In the second immobilized HPA additives are added to PFSA
ionomers synthesized by 3M to not only improve proton conduction under hot and dry conditions
but allow the oxidative stability of the film.
                                              O – 14




    Simulation of Reaction and Transport Processes in Fuel Cell Catalysts and
                                  Membranes
         William A. Goddard, III, Adri van Duin, Boris Merinov, Yao Sha, Ted Yu,
                              Seung Soon Jang, Gerald Voecks
                   Materials and Process Simulation Center (MC 139-74),
               California Institute of Technology, Pasadena, California 91125


     We will report here progress in using multiple paradigms for simulations of new materials
for catalysts and membranes toward improved fuel cell performance. Dramatically improving the
performance of fuel cells systems with their complex heterogeneous structures involving
electrocatalysts, proton conducting membrane, reactant, and interfaces between them requires
understanding the fundamental chemical, electrochemical, and physical phenomena at the heart
of these complex materials and relating these fundamentals to the properties and performance of
the membrane-electrode assembly.
     Our goal is to develop predictive models that can be used to estimate the changes in
performance upon changes in the design and which can be used to monitor performance of
working fuel cells. Our strategy is to start with first principles quantum mechanics and to
develop overlapping simulation methodologies in which quantum mechanics is used to train a
reactive force field that can be applied for large-scale (many 1000s of atoms) molecular
dynamics simulations while retaining the accuracy of quantum mechanics.
     Our expectation is that this model would enable the conception, synthesis, fabrication,
characterization, and development of advanced materials and structures for fuel cells. We
illustrate here some of the progress toward this goal.
                                                O – 15




             Alternative Materials to Pd Membranes for Hydrogen Purification

                               Thad Adams and Paul S. Korinko
                              Savannah River National Laboratory,
                                  Thad.Adams@srnl.doe.gov


The cost effective production of high purity hydrogen is required to move hydrogen fuel cell
technology from limited application to more widely accepted use. Current hydrogen purification
routes commonly use high value precious metals for purification. For instance, hydrogen is often
purified using palladium-silver membranes in systems referred to as diffusers. These diffusers
are often expensive and may be variable reliability. Consequently, alternative materials for the
Pd-Ag membranes are of interest.

To address this niche market, SRNL has been developing a “common metallic alloy” for use as a
replacement membrane material for hydrogen diffusers. The alloys of interest contain nickel,
vanadium, and titanium. Like the Pd alloys they are susceptible to hydriding under certain
temperature conditions and experience brittle fracture if cooled in the presence of hydrogen. This
presentation will describe the attributes of the alloys that have been tested and will show relative
permeation rates using both electrochemical cell measurement and gas permeation techniques.

WSRC-STI-2007-00379
Prepared for the U.S. Department of Energy under Contract DE-AC09-96SR185
                                               O – 16




                    Carbide-Derived Carbons for Hydrogen Storage

  Gleb Yushin1, Ranjan K.3 Dash1, Cristelle Portet1, Sebastian Osswald1, Yury Gogotsi1, 3
Taner Yildirim2, Huyn Seok , Giovanna Laudisio3, Jonathan P. Singer3, and John E. Fischer
  1
      Department of Materials Science and Engineering and A.J. Drexel Nanotechnology
                  Institute, Drexel University, Philadelphia, PA, 19104, USA.
      2
        National Institute of Standards and Technology, Gaithersburg, MD, 20899, USA.
        3
          Department of Materials Science and Engineering, University of Pennsylvania,
                                  Philadelphia, PA, 19104, USA.



Cryo-adsorption is a promising method of enhancing gravimetric and volumetric onboard H2
storage capacity for the future transportation needs. Inexpensive carbide-derived carbons (CDC),
produced by chlorination of metal carbides, have 50-80% open pore volume with tunable pore
size and high specific surface area (SSA). Tuning the carbon structure and pore size with high
sensitivity by using different starting carbides and chlorination temperatures allows rational
design of carbon materials with enhanced C-H2 interaction and thus increased hydrogen storage
capacity. Systematic experimental investigation of a large number of CDC with controlled pore
size distributions and SSA show that smaller pores increase both the heat of adsorption and the
total volume of adsorbed H2. It has been demonstrated that increasing the average heat of H2
adsorption above 6.6 kJ/mol substantially enhances H2 uptake at 1 atm and -196 oC. H2 storage
measurements on CDC of various particle size and surface termination at up to 60 atm will be
presented and materials challenges for designing advanced carbon-based adsorbents will be
discussed.
                                             O – 17




            Storage of Molecular Hydrogen in Carbon Based Systems
                                    Sa Li and Puru Jena
                  Department of Physics, Virginia Commonwealth University,
                                 Richmond, VA 23284, USA


     The early promise of nanoscale carbon (activated carbon, single-wall nanotubes and
fullerenes, nanofibers, and nanohorns) as hydrogen storage materials has not materialized. It has
been demonstrated that any reported capacity of higher than 1 wt% in carbon nanotubes is due to
experimental error. Theoretical study also confirms that high hydrogen content in the pure
carbon nanotubes cannot be achieved through physical sorption. Although recent theoretical
research has shown that doping of transition metal atoms such as Sc and Ti on carbon fullerenes
and nanotubes may fundamentally change the nature of hydrogen bonding and lead to materials
with hydrogen gravimetric density of up to 8 wt %, later calculations demonstrated that transition
metal atoms coated on these surfaces will cluster. This in turn would not only affect the nature
of hydrogen bonding but also the amount of stored hydrogen. The clustering of transition metal
atoms also has been shown to play an adverse role in transition metal doped polymers.
     We will discuss two different carbon based systems where hydrogen can be stored
molecularly to meet the requirements of the transportation industry. One such system is Li doped
cis-polyacetylene while the other is nano-porous carbon. Using density functional theory we
show that Li atoms doped in cis-polyacetylene, similar to Li doped C60, will not coalesce and can
bind hydrogen in molecular form with large gravimetric density. However, the binding of
hydrogen is weak and cryogenic temperatures are needed for hydrogen sorption. Fortunately,
modifying the chemistry of the inner pores of graphite provides certain advantages for hydrogen
storage. We show that each Ti atom doped in a graphene pore (porous carbon) can bind up to
four H2 molecules much the same way it does when supported on a C60 fullerene or carbon
nanotube. More importantly, the Ti atoms do not cluster inside the pore and hence can retain
their individual hydrogen storing capability.
     The calculations also reveal that the nano-porous carbon is magnetic with or without Ti
doping, but magnetism disappears when the pores are fully saturated with hydrogen. The
observation of magnetic porous carbon may have applications far beyond its ability to store
hydrogen.
                                               O – 18




                       Hydride Chemistry in Nanoporous Scaffolds

                  John J. Vajo a, Adam F. Gross a, Robert D. Stephens b,
                      Tina T. Salguero a, Sky. L. Van Atta a, Ping Liu a
                    a
                      HRL Laboratories, LLC, Malibu, California, USA
       b
         General Motors Research and Development Center, Warren, Michigan, USA


     Light element and complex anion hydrides (such as LiH, MgH2, NaAlH4, and LiBH4) are
attractive for fuel cell-based transportation applications because they have high gravimetric and
volumetric capacities. However, the thermodynamic properties of these materials, which
determine the operating temperatures, are often not compatible with proton exchange membrane
(PEM) fuel cells. In many cases, the thermodynamic stability and, consequently, the
temperatures for hydrogen delivery are too high. We have addressed this problem by combining
stable hydrides with additional elements or compounds to form destabilized chemical systems
that have much lower operating temperatures; examples include LiH/Si and LiBH4/MgH2. The
additives are chosen such that new compounds or alloys are formed during dehydrogenation.
The stability of these new phases lowers the enthalpy for dehydrogenation, thereby lowering the
operating temperature. In this talk, we will briefly describe our efforts using this approach.
     In addition to issues associated with thermodynamic properties, the rates at which hydrogen
absorbs into and desorbs from light metal and complex hydrides are typically much too slow at
PEM fuel cell temperatures. The slow rates originate, at least in part, from the high activation
energies for hydrogen diffusion associated with the ionic and covalent bonds found in these
hydrides. Small quantities of catalytic additives have been shown to greatly improve the rates of
hydrogen exchange in MgH2 and NaAlH4. We have explored another approach in which hydride
materials are incorporated into nanoporous scaffolds. The pores of the scaffold limit the
crystallite sizes of the hydride and thus the diffusion lengths to nanoscale dimensions. The
limitation of diffusion lengths reduces overall diffusion times and increases overall rates of
hydrogen exchange. The limited crystallite sizes also increase the interfacial area between
reacting phases, which improves hydrogen capacity retention during cycling. This talk will focus
on the hydrogenation and dehydrogenation chemistry of hydrides such as LiBH4, MgH2 and
NaAlH4 incorporated into nanoporous carbon aerogels.
                                                 O – 19




 High Density H2 storage on Nanoengineered Scaffolds of Carbon Nanotubes
      Carter Kittrell, A. D. Leonard, S. Chakraborty, H. Fan, W. E. Billups, R. H. Hauge, H. K.
                                 Schmidt, M. Pasquali, J. M. Tour,
                 Department of Chemistry, Rice University, Houston, Texas, 77005
                                      E-mail: kittrell@rice.edu


     An ideal media for hydrogen storage by physisorption should inherently be a multi-
functional material, which addresses at least six major criteria: gravimetric and volumetric
capacity, kinetics, heat transfer, energy efficiency, and reversibility [1]. A fibrous
nanoengineered framework of carbon nanotubes could have well-controlled pore sizes so that
there is little wasted volume of oversized pores, and super-packing of H2 provide high density
uptake. The linear structure minimizes tortuosity compared to granular media, and no activation
barrier for adsorption is ideal for the fastest kinetics and maximum energy efficiency.
Physisorption of 1 kg/min of hydrogen at room temperature (RT) will liberate ca. 250 kW, and
single wall carbon nanotubes (SWNTs) are unsurpassed in thermal conductivity. This scaffold
accommodates metal atoms or nanoparticles, which are predicted to bind H2 at RT, and provides
a heat sink for each. A rigid nanoscale structure will not distort with total H2 removal, for
unlimited cycling.
     We have recently suggested such a nanoengineered material, constructed from carbon
nanotubes that are spun as aligned fibrous media [2]. The fiber is expanded and bonded with
cross-linkers which determine the tube-tube spacing. As the DoE 2015 target volumetric
capacity exceeds the density of liquid hydrogen, it is not possible to meet this criterion unless the
uptake of the pore is enhanced. Surrounding the H2 with sp2 electron clouds yields a highly
favorable equilibrium constant that packs the pore, as theoretically predicted for graphene [3].
We will show experimental confirmation for this prediction of super-packed hydrogen pores
whereby a number of our 3D nanoengineered scaffold samples have been tested [4] and we have
consistently fit these data to a ~2x steeper slope for Chahine’s rule whereby the H2 uptake per
unit area is essentially double that of amorphous carbon adsorbents. Progress on alkali metal
functionalization of CNT for hydrogen uptake will also be presented. This work is supported by
DoE DE-FC36-05GO15073 in partnership with the NREL Hydrogen Storage Center of
Excellence.


[1]    From a presentation by M. Dresselhaus, UCSB H2 Symposium (8/28/06)
[2]    Ericson, Lars M., et al., Science, 2004, 305, 1447-1450
[3]    S. Patchkovskii, G. Seifert, et al., PNAS 2005;102;10439-10444 (2005)
[4]    H2 uptake measurement: National Renewable Energy Laboratory, Golden, CO
                                             O – 20




    H2 Binding and Reactivity on Transition Metal Complexes Underlying
        Biomimetic H2 Production and New Materials for H2 Storage
                                   Gregory J. Kubas
        Chemistry Division, Los Alamos National Laboratory, Los Alamos, NM 87545
                                  Email: Kubas@lanl.gov

The H2 molecule is held together by a very strong two-electron H–H bond but is only useful
chemically when the two H’s are split apart in controlled fashion. The reverse of this process is
formation of H2 from for example protons and electrons as performed elegantly and efficiently in
Nature by hydrogenase enzymes. Both splitting of H2 and formation of H2 occurs on transition
metal complexes via binding of molecular H2 to the metal center, often observed as stable solids.
Splitting of H2 occurs by both homolytic (dihydride formation) and heterolytic (formation of
metal hydride plus proton) pathways depending on the nature of the metal complex. The
molecular chemistry and spectroscopic features of dihydrogen complexes will be the major topic
of this talk. We are engaged in synthesizing catalysts for biomimetic photocatalytic hydrogen
production consisting of first-row metals such as iron capable of binding and splitting/forming
H2. Hydrogen binds reversibly to a surprisingly large variety of both metal and main-group
atoms, especially at low temperatures, and we are also studying such H2 complexes for hydrogen
storage.
                                               O – 21




              Material Issues in Photobiological Hydrogen Production
                                        Anastasios Melis
     University of California, Plant and Microbial Biology, Berkeley, CA 94720-3102, USA

      Issues pertaining to photosynthetic cell modification, photobioreactor materials
development, and the state of the art in these fields will be addressed. The research aims to
modify and redirect green algal photosynthesis for enhanced hydrogen (H2) production, coupled
with parallel efforts to design and deploy the cheapest possible scale-up facility for the
commercial production of H2 gas. A three-pronged approach seeks to (i) increase the continuity
and yield of H2-production in the model green alga Chlamydomonas reinhardtii, (ii) optimize the
absorption and utilization of sunlight by the cells so as to achieve the maximum possible solar-
to-chemical conversion efficiency, and (iii) to explore affordable bioreactor designs that are best
suited for photosynthetic H2 production, harvesting, and sequestration.
      (i) Improvement in the continuity and yield of green algal hydrogen production can be
achieved upon attenuation of the photosynthesis/respiration capacity ratio in the cells, such that
cellular respiration entirely consumes the photosynthetically generated oxygen. Anaerobiosis,
i.e., the absence of oxygen, is a prerequisite for photobiological H2 production. Under anaerobic
conditions, afforded by an attenuated photosynthesis/respiration capacity ratio in the cells,
spontaneous and sustained photosynthetic H2-production is observed. Recent advances are based
on the genetic identification of the chloroplast sulfate permease, followed by genetic engineering
for the attenuation of sulfate uptake by this photosynthetic organelle. A slow-down in the supply
of sulfates to the chloroplast causes limitation in the capacity and rate of photosynthesis, and
permits cellular respiration to quantitatively consume photosynthetic oxygen and, therefore, to
promote a spontaneous and sustained H2-production.
      (ii) Green algae under bright sunlight have low solar-to-chemical conversion efficiencies.
Reason is the large arrays of light absorbing chlorophyll antenna molecules in the photosystems
where, under bright sunlight, the rate of photon absorption far exceeds the rate at which
photosynthesis can utilize them, resulting in dissipation and loss of the excess energy as
fluorescence or heat. Up to 80% of absorbed photons could thus be wasted, lowering solar
conversion efficiencies and cellular productivity. The work identified genes that regulate the
chlorophyll antenna size of photosynthesis, and described manipulation of their expression to
attain a “truncated chlorophyll antenna size”. The latter helps to diminish over-absorption and
wasteful dissipation of excitation energy by individual cells, while permitting for greater
transmittance of sunlight deeper into a high-density mass culture. Such altered optical properties
of the cells result in greater photosynthetic productivity and better overall solar conversion
efficiency of the mass culture. The above-described advances, based on genetic modifications of
the green algae, compromise cell fitness and survival of the strains in the wild but promote the
conditions needed for efficient mass cultivation in photobioreactors, thus promoting enhanced
photosynthetic H2 gas production.
      (iii) Properties and costs of tubular modular photobioreactor facilities, which are suitable for
the scale-up of green algal mass cultures, and for H2-production and harvesting will also be
presented.

Work supported by the DOE Hydrogen, Fuel Cells and Infrastructure Technologies program.
                                            O – 22




                Hydrogen Production from Hydrocarbons by using
                        Oxygen Permeable Membranes
                                     Hitoshi Takamura
 Department of Materials Science, Graduate School of Engineering, Tohoku University, 6-6-11-
                     301-2 Aramaki Aza Aoba, Sendai 980-8579, Japan
                           Email: takamura@material.tohoku.ac.jp


Mixed oxide-ion and electronic conductors have been widely studied for use as electrodes of
solid oxide fuel cells and as oxygen permeable membranes. The oxygen permeable membranes
are of interest, in view of their promising applications, such as the production of pure oxygen
from air and hydrogen from hydrocarbons. To put a novel reformer using the membrane into
practice for partial oxidation of hydrocarbons (MPOX reformer), we have recently developed a
composite-type membrane consisting of Sm-doped CeO2 as an oxide-ion conductor and
MnFe2O4 as an electronic conductor has been developed [1, 2]. The composite of Sm-doped
CeO2 - 15 vol% MnFe2O4 (CSO-15MFO) shows a high oxygen flux density of 10 mol•cm-2•s-1
( 13.4[STP]cm3•cm-2•min-1) at 1000 °C, and a thermal expansion coefficient (TEC) of 12 x 10-6
K-1 between room temperature and 1000 °C. In the first part of the talk, the fabrication and
characteristics of the planar-type methane reformer using the ceria-based oxygen permeable
membrane will be presented. A single module reformer with dimensions of 6 cm x 6 cm showed
an oxygen flux density of 3.3 mol•cm-2•s-1, CH4 conversion rate of 94.1 %, CO selectivity of
85.7 %, H2 selectivity of 92.1 %, and H2 production volume of 360 sccm at 780 ˚C, where
methane and air flow rates were 150 and 500 sccm, respectively. This reformer was also found to
start up in 20 min. The advantages of the MPOX reformer in the context of exergy usage, and
cation diffusion behavior that controls the durability of the membrane will be discussed. The
second part of the talk will be devoted to the enhancement of oxygen permeability by using
nanoparticle technologies. For example, to promote surface exchange reaction, the Langmuir-
Blodgett film of PtFe nanoparticles was prepared and applied to the oxygen permeable
membrane surface. In addition, the possibility of oxide-ion conductivity enhancement in ceria
will be presented.

[1] H. Takamura et al., J. Electroceramics, 13 (2004) 613-618.
[2] H. Takamura et al., J. Alloys Comp., 408-412 (2006) 1084-1089
                                              O – 23




 Direct Production of Pressurized Hydrogen from Waste Aluminum without
                              Gas Compressor
                     T. Hirakia, N. Okinakaa, H. Uesugib and T. Akiyamaa
 a
   Center for Advanced Research of Energy Conversion Materials, Hokkaido University, Kita 13
                           Nishi 8, Kita-ku, Sapporo 060-8628, Japan
      b
        Waseda University, Wasedatsurumaki-cho 513, Shinjuku-ku, Tokyo 162-0041, Japan


An innovative environment-friendly hydrolysis process for generating high-pressure hydrogen
with recycling waste Al has been proposed and experimentally validated [1]. The effect of the
concentration of NaOH solution on H2 generation rate was mainly examined. In the experiments,
distilled water and Al powder were placed in the pressure-resistance reactor made of Hastelloy,
and was compressed to a desired constant water pressure using a liquid pump. The NaOH
solution was supplied by liquid pump with different concentrations (from 1.0 to 5.0 mol/dm3) at
a constant flow rate into the reactor by replacing the distilled water and the rate of H2 generated
was measured simultaneously. The liquid temperature in the reactor increased due to the
exothermic reaction given by Al + OH– + 3H2O = 1.5H2 + Al(OH)4– + 415.6 kJ. Therefore, a
high-pressure H2 was generated at room temperature by mixing waste Al and NaOH solution. As
the H2 compressor used in this process consumes less energy than the conventional one, the
generation of H2 having a pressure of almost 30 MPa was experimentally validated together with
Al(OH)3—a useful by-product. The exergy losses in the proposed system (150.9 MJ) is 55% less
than that in the conventional system (337.7 MJ) in which the gas compressor and production of
Al(OH)3 consume significantly more energy.


[1] T. Hiraki, et. al., Environ. Sci. Technol., 41, 4454-4457, 2007
                                              O – 24




         Indirect, Reversible Hydrogen Storage in Metal Ammine Salts:
                         Recent Progress and Prospects
                                   Claus Hviid Christensen
Center for Sustainable and Green Chemistry, Department of Chemistry, Building 206, Technical
                     University of Denmark, DK-2800 Lyngby, Denmark.
                       E-mail: chc@kemi.dtu.dk. Tel. No. +45 45252402


 Many consider the hydrogen economy a possible solution to significant global challenges. The
possibilities of improving the efficiency of energy conversion processes and reducing the
reliance on fossil fuels are main drivers for the currently increasing research and development
efforts but environmental concerns are also gaining importance. Despite the on-going efforts,
significant technological breakthroughs are still necessary for making a hydrogen economy
viable. The three most important challenges relate to: hydrogen production, hydrogen storage,
and hydrogen consumption. In particular, it seems that development of appropriate hydrogen
storage and transportation technologies will be a major hurdle. Recently, the use of metal
ammine salts as safe, reversible, high-density and low-cost hydrogen carriers was proposed
according to the Figure below. In the presentation, it is shown how this development could
provide a platform for using ammonia as a fuel for the hydrogen economy. It appears that in
several scenarios, this offers significant new opportunities that should be explored in more detail.
To fully elucidate the potential of this new method, we have studied the use of a wide range of
ammine salts as potential hydrogen storage materials by a combination of experimental and
theoretical methods.




To give an impression of the scope of the chemistry of metal ammines, the Figure above shows
van’t Hoff plots of over 90 metal ammine halides of the general formula M(NH3)nX2. With these
materials there are obviously many opportunities for selecting metal ammine salts with the
desired ammonia bond strength, i.e. with an appropriate desorption temperature. Moreover, we
have found that it is generally possible to compress the metal ammine salts into very dense
tabelts that have densities that are more than 95% of the crystal density. Thus, these tablets are
essentially compact and that results in very high volumetric hydrogen storage capacities as
shown in the Figure below.
                                        O – 24 (Contd.)




Currently, such tablets are produced on the kg-scale and even in these systems the desorption of
ammonia is facile. We also show that with micro-fabricated catalytic reactors, it is possible to
decompose ammonia to hydrogen at temperature of about 500 K. Interestingly, the metal
ammine salts will this year be tested in diesel cars as sources of ammonia for pollution abatement
in the SCR of NO and NO2. This will demonstrate if the system can be easily used in automotive
applications.
                                           O – 25




                    Alkali Aminoboranes for Hydrogen Storage
                                        Ping Chen
         Department of Physics, National University of Singapore, Singapore 117542


The combinations of amides and hydrides Interactions between N-H contenting chemicals and
hydrides produce hydrogen. Such strong interactions enable these substances potential hydrogen
storage materials. In the previous investigations, ~ 10.5wt.% and 5.5 wt.% of hydrogen storage
capacities have been achieved in lithium amide-lithium hydride and magnesium amide-lithium
hydride systems, respectively. However, the dehydrogenation temperatures (180 – 300 °C) are
somehow higher than the operation temperature of PEMFC (80 °C) due to thermodynamic
and/or kinetic reasons. Through compositional and structural alterations, the thermodynamics
and kinetics of subject material can be improved. Successful attempts have been achieved to
alkali aminoborane systems, in which more than 10 wt% of hydrogen can be desorbed at
temperatures around 90 °C. A few new structures have been developed and characterized.
                                             O – 26




                    Structure and Dynamics of Ammonia Borane

                                       Thomas Autrey
  Molecular Interactions & Transactions, Pacific Northwest National Laboratory, PO Box 999,
                                 Richland, WA 99352, USA
                              E-mail:     tom.autrey@pnl.gov

Amine boranes are attractive candidates for the storage of high volumetric and gravimetric
densities of hydrogen for fuel cell powered devices. The parent compound, ammonia borane
(NH3BH3), isoelectronic with ethane, yet it is a solid molecular crystal under standard conditions.
Ammonia borane is stable at room temperature but will desorb >15 mass% hydrogen at moderate
temperatures. Our group has been investigating the thermal and catalytic mechanisms of amine
borane decomposition leading to hydrogen formation. We believe that the interactions between
the hydridic BH and protic NH hydrogen are responsible for the low activation barriers for
hydrogen desorption. In this presentation, we will discuss our experimental and computational
research aimed at developing a fundamental understanding of the chemical and physical
properties of these hydrogen rich materials.


This work is supported by the US Department of Energy, Basic Energy Sciences Hydrogen Fuel
Initiative. Battelle operates PNNL for DOE.
                                             O – 27




       Molecular Simulation of Structural Changes of Ammonia Borane
 Gregory K Schenter, Chris Mundy, Shawn M Kathmann, Vencislav Parvanov, Nancy J Hess,
                   Wendy J Shaw, Herman M Cho and Thomas Autrey,
               Pacific Northwest National Laboratory, Richland, WA 99352
                             E-mail: greg.schenter@pnl.gov


We will report studies of the structural changes of Ammonia Borane as a function of temperature
using molecular simulation techniques, relating them to neutron diffraction and NMR
measurements. A series of molecular simulations were performed at temperatures of 15, 120,
175, 220, 230, 240, 250, 275, and 330K, spanning the structural phase transition from an
orthorhombic to a tetragonal phase at 225K. It is believed that this transition is related to the
rotational dynamics of the NH3 and BH3 moieties, and a better understanding of the details these
motions will provide insight into the hydrogen release mechanism for this class of materials.
Calculations were performed combining Density Functional Theory electronic structure
calculations of molecular interaction with statistical sampling of the canonical ensemble using
the CP2K simulation code. A 16-molecule cell was sampled using the PBE functional with a
TZVP basis set. The progression of the average structure and fluctuations across the phase
transition will be presented and their consequences in the interpretation of NMR lineshape
analysis and neutron powder diffraction pair distribution function.


                                                         s
This work was supported by the U.S. Department of Energy' (DOE) Office of Basic Energy
Sciences, Chemical Sciences program and the Hydrogen Fuel Initiative. The Pacific Northwest
National Laboratory is operated by Battelle for DOE
                                             O – 28




Characterization of Complex Metal Hydrides by High-Resolution Solid State
                                 NMR
                         Robert. C. Bowman, Jr.1 and Son-Jong Hwang2
         1
          Jet Propulsion Laboratory, Mail Stop 79-24, California Institute of Technology,
                                Pasadena, CA 91109-8099, USA
2
  Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena,
                                        CA 91125, USA
                            E-mail: robert.c.bowman-jr@jpl.nasa.gov


Insights on the compositions, chemical bonding, and structures of complex metal hydrides (i.e.,
alanates, borohydrides, and amides/imides) are being obtained via multinuclear nuclear magnetic
resonance (NMR) studies. By implementing advanced solid-state NMR techniques such as
Magic Angle Spinning (MAS), cross-polarization (CP) MAS, and multi-quantum (MQ) MAS;
these NMR measurements can provide very detailed information on the complicated
relationships amongst various processes accompanying the formation of hydride phases and their
transformations, including reaction kinetics, reversibility, and the roles of catalysts. Because
short range interactions dominate NMR parameters, highly disordered as well as amorphous
materials can be more thoroughly evaluated via solid state NMR than is typically possible with
x-ray or neutron diffraction studies since the latter usually require good crystallinity as well as
sufficiently large domain sizes. Several examples are taken from our recent investigations on
high-capacity hydrogen storage candidates to illustrate how these high-resolution NMR
techniques can address and often resolve diverse issues on phase formation and decomposition
processes. First, the behavior of Sc-doping on the phase compositions and reactivity of the
sodium tetra- and hexa-alanates has been assessed from the 45Sc, 27Al, and 23Na spectra
following mechanical milling and hydrogen absorption/desorption treatments. Second, the
formation and subsequent hydrogen desorption from several borohydride phases based upon Li,
Mg, and Sc was investigated using 11B MAS and CPMAS spectra that included clear evidence
for the formation of highly stable intermediate “BnHm” species in their x-ray amorphous
decomposition products that severely impact their ability to reform the initial borohydride
phases. Finally, NMR was used to assess the reversibility of several combinations in the Li-Mg-
Al-N-H system that independently validated proposed reactions that could not be confirmed by
x-ray diffraction or other methods.
                                             O – 29




     Hydrogenography: A combinatorial thin film approach to identify the
                thermodynamic properties metal hydrides
                                      Bernard Dam
  Condensed Matter Physics, Department of Physics and Astronomy, Faculty of Science, Vrije
        Universiteit, De Boelelaan 1081, NL-1081 HV Amsterdam, The Netherlands

The search for new light-weight metal-hydride storage materials is essentially that for a needle in
a haystack. Although computational methods have become more and more realistic, their
predictive power is still limited. Experimentally, the determination of the plateau pressures of
bulk samples is a very time consuming procedure. This explains the renewed interest in high-
throughput experimental methods. We demonstrate that the change in optical properties on
hydrogenation make metal hydrides perfectly suited for a thin film combinatorial search for new
hydrogen storage materials. Using Hydrogenography, we measure simultaneously the enthalpy
of hydride formation of thousands of materials on a single thin film wafer. From extrapolation of
the optically measured Van ‘t Hoff plots, we obtain the entropy of formation. In the ternary Mg-
Ti-Ni phase diagram, we demonstrate the destabilizing effect of Ti dopants on Mg2Ni-hydride.
Furthermore, we identify a composition region of Mg-rich Mg-Ti-Ni alloys that absorb hydrogen
with enthalpies of formation between -40 and -37 kJ/(mol H2). Using very thin layers of Pd we
reproduce the Van ‘t Hoff relation both in absorption and desorption, fully in accordance with
previous literature data. This shows that the technique is not limited to systems with a metal
insulator transition. Since the chemisorption of hydrogen will always lead to some change in
electronic structure, we think that our method is generally applicable.
                                            O – 30




      First-principles engineering of advanced hydrogen storage materials

                                      Vidvuds Ozolins
           Department of Materials Science & Engineering, University of California,
                                        Los Angeles


Hydrogen-fueled vehicles require a cost-effective, light-weight material that binds hydrogen
strongly enough to be stable at ambient pressures and temperatures but weakly enough to liberate
H2 with minimal heat input. Since none of the simple metal hydrides satisfy all the requirements
for a practical H2 storage system, recent research efforts have turned to complex hydrides and
advanced multicomponent material compositions. We will show how first-principles density-
functional theory (DFT) calculations have become a valuable tool for understanding and
predicting novel hydrogen storage materials. Recent studies in our group have used DFT
calculations to (i) predict crystal structures of new solid-state hydrides, (ii) determine phase
diagrams and thermodynamically favored reaction pathways in multinary hydrides, and (iii)
study microscopic kinetics of hydrogen release reactions. We have developed theoretical
methods for determining crystal structures and thermodynamic properties of novel complex
hydrides, which allow accurate theoretical predictions of hydrogenation enthalpies without any
experimental input. Using Li-Mg-N-H and Li-Mg-B-N-H as examples, we will demonstrate that
phase diagrams and hydrogenation reactions in multicomponent systems can be determined
entirely from the first principles. Finally, we will show recent DFT results that elucidate the
kinetics of H2 release and mass transport in the prototypical complex hydride, sodium alanate.
                                                        O – 31




                 Development of Metal Hydrides for High-Pressure MH Tank
                    T. Matsunaga*, T. Shinozawa, K. Washio, D. Mori, M. Ishikiriyama
        Higashifuji Technical Center, Toyota Motor Corporation, 1200, Mishuku, Susono, Shizuoka,
                                            410-1193, JAPAN
                               *E-mail: tomoya@matsunaga.tec.toyota.co.jp


          Hydrogen storage method is one of the most important issues to introduce fuel cell vehicles.
     Although compressed hydrogen gas tank is convenient in charge and discharge process of
     hydrogen, its volumetric storage density is limited to less than 20kg/m3 and it is not sufficient.
     High pressure metal hydride(MH) tank (Fig.1) can holds more than twice the amount of
     hydrogen as compared to the same volume of 35MPa compressed hydrogen gas tank. This
     system has a potential to be used as conveniently as a compressed hydrogen gas tank.
          The merit of the high pressure MH tank system is improved by the use of a metal hydride
     with high desorption pressure. In this study, TiCrV and TiCrVMo alloy with BCC structure has
     been developed for this system and it shows 2.5 mass% of effective hydrogen capacity (Fig.2).
     Generally, the plateau pressure of metal hydrides increases with the decrease of the lattice size.
     This was also observed for TiCrV ternary alloy. However, for TiCrVMo alloy, the desorption
     pressure is sensitive not only to the lattice size but also to the content of Mo, and it turned out
     that Mo has the special effect to increase the desorption pressure of the hydride. Besides the
     results as a material, hydrogen charging/discharging properties as a high pressure MH tank with
     the developed materials will be also presented.

                                                                     100
                                                                               298 K
Aluminum fin of hot exchanger CFRP Aluminum liner
                                                                         10
                                                        Pressure [MPa]




      H2                                      Coolant                      1

                                                                                                     TiCrVMo
        Valve                                                            0.1
                                                                                                     TiCrV
                  MH            tubes      Sealing
                  powder                                                                             TiCrMn
                                                                 0.01
     Fig 1.Schematic view of high-pressure MH                        0.0                1.0        2.0         3.0
                                                                                       hydrogen [mass%]
                        tank
                                                                          Fig 2.PC isotherms of the developed MHs
                                             O – 32




                    Materials Challenges in Solid Oxide Fuel Cells
                                           S. C. Singhal
                             Battelle Fellow and Director, Fuel Cells
                             Pacific Northwest National Laboratory
                                      902 Battelle Boulevard
                                   Richland, WA 99352, USA


The high oxide ion conductivity over wide ranges of temperature and oxygen pressures in
stabilized zirconia has led to its use as a solid oxide electrolyte in a variety of electrochemical
applications. These include high temperature solid oxide fuel cells (SOFCs) which offer a clean,
low-pollution technology to electrochemically generate electricity at high efficiencies. These fuel
cells provide many advantages over traditional energy conversion systems including high
efficiency, reliability, modularity, fuel adaptability, and very low levels of SOx and NOx
emissions. The most progress to date has been achieved with the tubular design cells; however,
their electrical resistance is high, and specific power output (W/cm2) and volumetric power
density (W/cm3) low. Planar solid oxide fuel cells, particularly anode-supported, in contrast, are
capable of achieving very high power densities and can be mass produced using low-cost
conventional ceramic processing and microelectronic fabrication techniques. This lecture will
review the materials, fabrication processes and performance of these solid oxide fuel cells and
discuss their applications in stationary power generation, transportation, and military market
sectors.
                                         O – 33




   The Development of Nano-Composite Electrodes for Natural Gas-
        Assisted Steam Electrolysis for Hydrogen Production
                               Raymond J. Gorte
           Chemical & Biomolecular Engineering, University of Pennsylvania


Electrodes are being developed for Solid Oxide Electrolyzers (SOE), especially those that
could be used for Natural-Gas Assisted Steam Electrolysis (NGASE). NGASE requires
electrodes that exhibit stable performance in dry methane, with low overpotentials, and
allow operation at high temperatures. A variety of novel air and fuel electrodes have been
developed and tested for SOE and NGASE devices. In all cases, the electrodes are made
by addition of the active, electrode components into porous yttria-stabilized zirconia
(YSZ) layers that had been pre-sintered with the YSZ electrolyte. Air electrodes based on
Sr-doped LaFeO3 (LSF) have been shown to exhibit superior performance to more
traditional LSM-based electrodes but can deactivate after long times or high
temperatures, apparently due to sintering of the LSF. Cu-based electrodes were found to
exhibit poor thermal stability above 1073 K due to sintering of Cu, but Cu-Co electrodes
prepared by Co electrodeposition onto the Cu composite had significantly improved
performance. It was shown that a Cu monolayer forms at the Co surface after heating in
H2 due to free-energy considerations, so that the Cu-Co electrodes exhibit the thermal
stability of Co and the chemical stability of Cu. Finally, a novel, all-ceramic electrode
was developed for use in fuel environments. The ceramic electrode consists of a thin
functional layer optimized for catalytic activity with a thicker conduction layer.
                                         O – 34




Near-surface alloys and Core-shell nanocatalysts for reactions involving
                              hydrogen
                               Manos Mavrikakis
Department of Chemical and Biological Engineering, University of Wisconsin-Madison,
                            Madison, Wisconsin 53706
       http://www.engr.wisc.edu/che/faculty/mavrikakis_manos.html#address


Using first-principles methods, we have identified bimetallic and ternary alloys with
specific nano-architecture and significantly improved catalytic properties for a variety of
applications, including electrocatalysis for low temperature fuel cells. These near-surface
alloys have been synthesized with atomic-layer thickness control in core-shell
nanoparticles and, upon experimental testing, have demonstrated remarkable catalytic
properties at low temperatures.
                                         O – 35




Hybrid Inorganic-Organic Polymer Composites for Polymer-Electrolyte
                             Fuel Cells
             Andrea Ambrosini, Cy H. Fujimoto, Christopher J. Cornelius
         Sandia National Laboratories, Albuquerque, NM; aambros@sandia.gov


Polymer electrolyte membrane (PEM) fuel cells are a key component in the development
of the Hydrogen Economy. One of the primary technical deficiencies of PEMs is their
poor performance at low relative humidities, due to reduced proton transport in the
polymeric membrane. This limitation complicates fuel cell systems and balance of plant
design, since the membranes must be near 100% humidified at all times. Because of these
humidity limitations, fuel cells utilizing current organic polymer membranes can operate
only at temperatures <100 ºC. The development of polymer electrolytes that can operate
between 120-150 ºC and at lower relative humidities will result in more efficient fuel cell
systems.
    Unlike polymeric membranes that require the presence of water for proton conduction
to occur, inorganic acids can conduct protons with minimal water content; however these
materials form membranes with poor physical properties (brittle, water soluble).
Heteropolyacids (HPA) are a structurally diverse group of inorganic “superacids,” which
exhibit high proton conductivity at ambient temperature. They are polyoxometalates that
consist of an inorganic Keggin anion balanced by monovalent cations such as protons. In
their hydrated forms, the anion clusters can be coordinated with a number of H2O
molecules, some of which can be retained at temperatures upwards of 200 ºC. Such water
retention properties can aid the hybrid membrane in proton conduction at lower relative
humidities. Merging organic polymers and inorganic compounds has led to the
development of hybrid materials that combine the facile processability of polymers with
the high temperature stability of inorganic materials.
    Previous work at Sandia has involved the development sulfonated Diels-Alder
poly(phenylene) (SDAPP) for use in PEM fuel cells.1 We have incorporated HPAs into
the SDAPP via several methods and characterized the resulting hybrid films by infrared
spectroscopy, thermogravimetric analysis, conductivity and ion-exchange capacity. The
structural and chemical properties of these hybrid films, as well as their conductivities
will be presented in this poster.
1
 Fujimoto, C. H.; Hickner, M. A.; Cornelius, C. J.; Loy, D. A., Macromolecules 2005,
38, 5010.
Sandia is a multiprogram laboratory operated by Sandia Corporation, a Lockheed Martin
Company, for the US DOE’s NNSA, contract DE-AC04-94-Al85000.
                                           O – 36




      Reaction Mechanism and Kinetics of Reactive Hydride Composites
 M. Dornheim1, U. Bösenberg1, C. Pistidda1, G. Lozano1, Y. Zhou1, C. Nwakwuo1, J.
 Bellosta v. Colbe1, G. Barkhordarian1, N. Eigen1, O. Metz1, T. Jensen2, M. Podeyn3, T.
                 Klassen3, S. Doppiu4, O. Gutfleisch4, and R. Bormann1
       1
           Institute of Materials Research, GKSS Research Centre Geesthacht, Germany
                       2
                         Department of Chemistry, University of Aarhus, Denmark
               3
                 Institute of Materials Science, Helmut-Schmidt-University, Germany
                     4
                       Institut für Metallische Werkstoffe, IFW Dresden, Germany


Compared to conventional room temperature hydrides, light weight metal hydrides have
much higher gravimetric hydrogen storage densities. However, kinetic and
thermodynamic restrictions limit the potential use of such high capacity hydrides. Due to
the use of high energy ball milling techniques for sample preparation as well as the
addition of suitable catalysts or dopants, the sorption kinetics of high capacity hydrides
could be improved significantly. Hydrogen absorption and desorption now is possible in
metal oxide catalyzed MgH2 within 2 min [1]. For catalyzed NaAlH4, hydrogenation
takes place within 10 min [2]. However there are still a lot of hydrides with high storage
capacities which have to be considered as irreversible or at least require high pressures
and very high temperatures for reversible hydrogenation/dehydrogenation as well as very
long absorption and desorption times. Prominent examples are borohydrides like LiBH4.
Another crucial parameter for the use of light weight metal hydrides as hydrogen
absorbing alloys for hydrogen storage applications is their reaction enthalpy. Most of the
past attempts to alter and tailor the hydrogen reaction enthalpy of light weight metal
hydrides like Mg either failed or led to dramatically reduced gravimetric hydrogen
storage capacities. This demonstrates the demand for novel approaches to enhance the
kinetics and alter the reaction enthalpies of lightweight hydrides. One very exciting,
successful and promising novel approach is the concept of the Reactive Hydride
Composites (RHC) [3]. Such systems show reduced total reaction enthalpies as well as
significantly improved ab- and desorption kinetics compared to the pure hydrides while a
high hydrogen storage capacity is maintained. Furthermore, in RHC reversibility is
demonstrated for hydrides, which have to be considered as irreversible using moderate
hydrogen pressures and temperatures.
        In this talk, we present recent detailed results on the sorption behaviour of doped
nanocrystalline Reactive Hydride Composites 2LiBH4+MgH2, 2NaBH4+MgH2 and
Ca(BH4)2+MgH2.

[1]        M. Dornheim et al., Advanced Engineering Materials 8 (2006) 377.
[2]        N. Eigen et al., Scripta Materialia 56(2007) 847.
[3]        G. Barkhordarian et al., Journal of Alloys and Compounds 440 (2007) L18.
                                         O – 37




    Single- and Double-Cations Borohydrides for Hydrogen Storage
                            Applications
      Shin-ichi Orimo1, Yuko Nakamori1, Haiwen Li1, M. Matsuo1, Toyoto Sato1,
                  Nobuko Ohba2, Kazutoshi Miwa2, Shin-ichi Towata2
                  1
                    Institute for Materials Research, Tohoku University,
                                   Sendai 980-8577, Japan
             2
               Toyota Central R&D Labs., Nagakute, Aichi 480-1192, Japan
                               E-mail: orimo@imr.tohoku.ac.jp


We have systematically investigated the thermodynamical stabilities of single cation
borohydrides M(BH4)n (M = Li, Na, K, Mg, Ca~Mn, Cu, Zn, Al, Y, Gd, Dy, Zr and Hf; n
= 1-4) and their intermediate phases by both first-principles studies and thermal
desorption measurements [1-5]. Recently, new series of double-cation borohydrides
MLim-n(BH4)m (M = Zn, n = 2; M = Al, n = 3; M = Zr, n = 4; n m) were also studied [6].
Thermal desorption measurements indicate that both ZnLi(BH4)3 and AlLi(BH4)4
disproportionate into Zn(BH4)2- (or Al(BH4)3-) and LiBH4-based phases upon heating,
respectively. However, no disproportionation reaction is observed in the case of ZrLim-
4(BH4)m. The hydrogen desorption temperature Td of ZrLim-4(BH4)m increases from 440 K
(m = 4) to 650 K (m = 6), and continuously approaches to 740 K (Td of LiBH4). That is,
Td of ZrLim-4(BH4)m, namely MM’(BH4)n, is closely related to the averaged
electronegativity of M and M’, as what have observed in M(BH4)n. Consequently, the
above-mentioned results indicate that the appropriate combination of cations is an
effective method to precisely adjust the thermodynamical stability of metal borohydrides,
similar to the conventional “alloying” method for hydrogen storage alloys. Microwave
irradiation effects on selected metal borohydrides and their composites were also
investigated experimentally [7, 8].


[1] Y. Nakamori et al., PRB 74 (2006) 045126.
[2] S. Orimo et al., APL 89 (2006) 021920.
[3] N. Ohba et al., PRB 74 (2006) 075110.
[4] K. Miwa et al., PRB 74 (2006) 155122.
[5] T. Sato et al., to be submitted.
[6] H.-W. Li et al., JALCOM, in press.
[7] Y. Nakamori et al., APL 88 (2006) 112104.
[8] M. Matsuo et al., APL 90 (2007) 232907.
                                         O – 38




       Tetrahydroboranates: The New Hydrogen Storage Materials

                    Andreas Züttel and Andreas Borgschulte
 EMPA Materials Sciences and Technology, Dept. Environment, Energy and Mobility,
Abt. 138 "Hydrogen & Energy", Überlandstrasse 129, CH-8600 Dübendorf, Switzerland


     Complex transition-metal hydrides provide new opportunities for hydrogen storage.
Their hydrogen-to-metal ratios reach values of up to H/M = 4.5 (BaReH9) and thus
surpass the hydrogen-to-carbon ratios of hydrocarbons (methane: H/C = 4); their
hydrogen-volume efficiencies exceed that of liquid hydrogen by a factor of up to two
(Mg2FeH6), their weight efficiencies exceed 5% (Mg3MnH7), and their hydrogen
dissociation temperatures under 1 bar hydrogen pressure range from ca. 100°C
(NaKReH9) to 400°C (CaMgNiH4). Their crystal chemistry is extremely rich and shows a
large inventory of transition-metal hydrido complexes that often conform to the 18-
electron rule. New synthetic methods are likely to yield further members of this class of
materials. Concepts, to find new synthetic routes, and to understand the factors that
govern hydride formation, hydrogen contents and thermal stability. In the review article
by Klaus Yvon1, the basics of complex-transition-metal hydrides are outlined.
     The group one two and three light elements (p-elements), e.g. Li, Mg, B, Al, build a
large variety of metal-hydrogen complexes. They are especially interesting because of
their light weight and the number of hydrogen atoms per metal atom which is in many
cases2. The hydrogen in the complex hydrides is often located in the corners of a
tetrahedron with boron or aluminum in the center. The negative charge of the anion,
[BH4]- and [AlH4]- is compensated by a cation e.g. Li or Na. The hydride complexes of
borane, the tetra-hydro-borates M[BH4], and of alane the tetrahydroaluminate M[AlH4]
are interesting storage materials, however, they were known to be stable and decompose
only at elevated temperatures and often above the melting point of the complex. The
hydrogen desorption from a complex hydride is a decomposition reaction. Very little is
know about the decomposition process. However, the compound does not decompose
into a metal lattice and hydrogen, it decomposes often into a alkali hydride, a metal and
hydrogen gas. In the bandstructure of the complex hydride often an almost complete
transfer of the electron from the cation to the [BH4] or [AlH4] –anion is found. Therefore,
in the decomposition reaction2 of a tetra-hydro-borate M(BH4) an H- is transferred from
the [BH4]- to the M+ and 3 hydrogen can be desorbed as 1.5 H2. Borohydrides e.g.
Li[BH4], Na[BH4], K[BH4] and Mg[BH4]2, Ca[BH4]2 form at elevated pressure and
temperature from the elements3. The enthalpy of formation of the complex hydrides can
be deduced from chemical reaction (indirect measurements of the stability)4. Due to the
formation of the MH, the desorption reaction takes place at a lower temperature (lower
energy) than the temperature deduced from the formation energy of M[BH4]. The
mechanisms of the hydrogen desorption and absorption as well as the hydrogen mobility
in the lattice will be discussed in detail.
                                O – 38 (contd.)



1
  Klaus Yvon, “Complex transition-metal hydrides”, Chimia 52:10 (OCT 1998), pp.
  613-619
2
  Andreas Züttel, Andreas Borgschulte and Shin-Ichi Orimo, “Tetrahydroborates as
  new hydrogen storage materials”, Scripta Materialia 56:10, (2007), pp. 823-828
3
  Goerrig D (1958), „Verfahren zur Herstellung von Boranaten“, Ger. Pat.
  1,077,644, 1-4
4
  William D. Davis, L.S. Mason and G. Stegeman, “The heats of formation of
  Sodium borohydride, Lithium borohydride and Lithium Aluminium Hydride”, J.
  Am. chem. Soc. 71 (1949), pp. 2775-2781
                                         O – 39




       Storage of Compressed Hydrogen in Multi-Capillary Arrays
                                   N. K. Zhevago
        Russian Research Centre “Kurchatov Institute”, Moscow 123182, Russia
                              nick_zhevago@tochka.ru

                                     Dan Eliezer
              Ben Gurion University of the Negev Beer Sheva 84105, Israel
                                  deliezer@bgu.ac.il


     Hydrogen storage is a key issue in the success and realization of hydrogen
technology and economy. Since the conventional hydrogen fuel storage methods of
pressuring H2 gas and cryogenic liquid H2 pose safety and permeation problem along
with high cost, they do not meet future on-board applications goals set for hydrogen
economy. Solid state hydrogen fuel storage either absorption in the interstices of metals
and metallic alloys or adsorption on high surface area materials such as activated carbon
gain the attention for possible future hydrogen applications. There is no perfect choice of
hydrogen store material to meet the set US DOE goals for transport application. The
success and realization of hydrogen economy using hydrogen stored solid fuel
technology will be dependent on the meeting of above goals.
     The present paper describes a novel method of hydrogen storage in the array of
sealed capillaries made of various materials. The suggested method ensures more safety
compared to usual tanks. Theoretical estimates show that using thin enough capillaries of
quartz, aramids or other materials with low specific weight to tensile strength ratio it is
possible to achieve or even surpass the DOE 2010 demands for the gravimetric and
volumetric capacity of the storage medium [1,2]. The different ways of refilling
capillaries with compressed hydrogen: permeation through the walls of primarily sealed
capillaries at elevated temperature and sealing of capillaries with metal alloys after
pumping hydrogen inside through the open end will be discussed in details. The
theoretical analysis of the resistance of the capillary arrays of the hydrogen pressure of
hydrogen loading and releasing will be presented.


 [1] V. G. Gnedenko, I. V.Goryachev, N. K. Zhevago "Apparatus for storage of
compressed hydrogen gas", U.S. Provisional Patent Application No 60/752,379
[2] N.K. Zhevago, V.I. Glebov, Energy Conversion and Management 48 (2007) 1554–
1559
                                         O – 40




   Structural-Metals Considerations for Hydrogen Gas Containment
                        Chris San Marchi and Brian Somerday
                   Sandia National Laboratories, Livermore, CA, USA
                             E-mail: cwsanma@sandia.gov


Two important safety considerations for the containment of hydrogen gas involve
interactions between hydrogen and the structural metals that contain the gas: (1)
hydrogen can permeate through metals creating an effective leak, and (2) hydrogen
dissolved in the metal can promote embrittlement. Both hydrogen-material interactions
are related to the propensity for molecular hydrogen to dissociate on the surfaces of metal
structures, producing atomic hydrogen that diffuses into these metals. All structural
metals can be vulnerable to hydrogen embrittlement under some intersection of
microstructural, mechanical, and environmental conditions, thus it is important to
develop a comprehensive understanding of the service conditions for a given application.
Important service variables include gas pressure, temperature, and mechanical loading
mode. In this presentation, we describe hydrogen embrittlement and its relationship to
service variables that can be expected in hydrogen containment applications.
Furthermore, we use data from the literature and data generated in our own laboratory to
demonstrate these general trends. Our continuing work is motivated by the needs of the
engineering community for material properties that can be used to define safety margins
for components exposed to hydrogen gas. As part of this work we emphasize appropriate
materials testing and structural design protocols that enable the construction of safe and
efficient high-pressure hydrogen components.
                                          O – 41




          A National Agenda for Hydrogen Codes and Standards
                                      Chad Blake
                         National Renewable Energy Laboratory
                             E-mail: Chad_Blake@nrel.gov


     For the past decade, the Office of Hydrogen, Fuel Cells and Infrastructure
Technologies in the U.S. Department of Energy (DOE) has sponsored a collaborative
national effort by government and industry to prepare, review, and promulgate codes and
standards needed to expedite hydrogen infrastructure development and to help enable the
emergence of hydrogen as a significant energy carrier. In addition, DOE has worked to
harmonize national and international standards, codes, and regulations that are essential
for the safe use of hydrogen by consumers in the U.S. and throughout the world. The
National Renewable Energy Laboratory (NREL) supports DOE in these efforts.
     A key to the emerging national agenda for hydrogen and fuel cell codes and
standards is the creation and on-going implementation of national templates through
which DOE, NREL, and key standards and model code development organizations
coordinate the preparation of critical standards and codes for hydrogen and fuel cell
technologies and applications. The national templates are accepted by the major standards
and model code development organizations in the U.S., the FreedomCAR and Fuel
Partnership, key industry associations, and many state and local governments as
guideposts for the coordinated development of standards and model codes. The National
Hydrogen and Fuel Cells Codes and Standards Coordinating Committee, formed to help
manage implementation of the templates, has created a “virtual national forum” for
standards and model code development organizations, industry, government, and
interested parties to address codes and standards issues, both immediate and long-term.
     DOE has also launched a comprehensive research, development, and demonstration
(RD&D) effort to obtain data needed to establish a scientific basis for requirements
incorporated in hydrogen codes and standards. This RD&D is planned, supported, and
evaluated by DOE in collaboration with the Codes and Standards Technical Team
(CSTT) of the U.S. FreedomCAR and Fuel Partnership. The CSTT has adopted a
Roadmap that identifies RD&D needs, gaps, and priorities related to the development of
codes and standards for a hydrogen-based transportation system. DOE implements the
Roadmap by supporting priority RD&D at its national laboratories, universities, and
industry.
     With the help and cooperation of standards and model code development
organizations, industry, and other interested parties, DOE has established a coordinated
national agenda for hydrogen and fuel cell codes and standards. With the adoption of the
RD&D Roadmap and with its implementation through the CSTT, DOE helps strengthen
the scientific basis for requirements incorporated in codes and standards that, in turn, will
facilitate international market receptivity for hydrogen and fuel cell technologies.
                                              O – 42




    Educating Key Audiences about Hydrogen and Fuel Cell Technologies
                                      Robert Remick
                           National Renewable Energy Laboratory
                             E-mail: Robert_Remick@nrel.gov


     Expanding the use of hydrogen as an energy carrier requires a sustained education
effort to lay the foundation for future commercial market introduction. Although
hydrogen and fuel cells are considered longer-term technologies, hydrogen fueling
stations and fuel cell vehicles are entering the public space today through demonstration
projects in certain regions of the country, and stationary fuel cells have already reached
the commercial market in some niche applications. Current knowledge and awareness
levels of hydrogen and fuel cells are low, however, and prevalent misunderstandings of
hydrogen properties have affected negative opinions about the safe use of hydrogen as an
energy carrier. Given the current and anticipated public visibility of hydrogen
demonstration projects – and the correlation between knowledge and opinion – a
carefully planned education program is needed.
     The U.S. Department of Energy (DOE) Hydrogen Program seeks to facilitate
hydrogen and fuel cell demonstration, deployment, and market transformation by
providing technically accurate and objective information to key target audiences both
directly and indirectly involved in the use of hydrogen and fuels cells today. These
audiences, identified in the National Hydrogen Energy Roadmap1, include safety and
code officials, state and local government representatives, local communities and the
public and potential end users. Undergraduate and graduate students, professors, and
middle and high school teachers, and students comprise another important audience, as
they are our Nation’s future researchers, scientists, engineers, technicians, and technology
users.
     A 2004 national Hydrogen Knowledge Survey serves as a baseline for measuring
changes in knowledge over time; program plans include repeating the survey in out-
years. The baseline results also provide important information about current knowledge
gaps, information needs, and opinions of hydrogen technologies that helps to inform the
ongoing development of DOE’s hydrogen education efforts.
     Developing hydrogen as a major energy carrier will require a combination of
technological breakthroughs, market acceptance, and large investments in infrastructure.
Success will not happen overnight; it will require an evolutionary process that phases
hydrogen in as the technologies and their markets are ready. The coinciding education
efforts must also assume phased a focused approach that considers technology readiness
and the DOE Hydrogen Program’s overall market transformation strategy.

1
 “National Hydrogen Energy Roadmap”
http://www1.eere.energy.gov/hydrogenandfuelcells/pdfs/national_h2_roadmap.pdf
                                         O – 43




 Hydrogen behavior and coloration of tungsten oxide films prepared by
          magnetron sputtering and pulsed laser deposition
           S. Nagata1), A. Inouye2), S. Yamamoto2), B. Tsuchiya1), T. Shikama1)
     1)
        Institute for Materials Research, Tohoku University, Sendai 980-8577, Japan
                 2)
                   Japan Atomic Energy Agency, Takasaki 370-1292, Japan
                                  nagata@imr.tohoku.ac.jp


     Hydrogen fuel is considered to be a clean energy resource for the future. Because
the hydrogen gas has a relatively low explosive limit in the atmosphere, development of a
sensor of hydrogen gas is very important to handle hydrogen safely. Tungsten tri-oxide
films covered with a thin catalyst layer is one of the candidates for hydrogen sensing
devices that show a reversible coloration phenomenon under hydrogen exposure.
Meanwhile, the mechanism of the gasochromic phenomenon is not fully understood. In
the present study, the relation between the hydrogen and gasochromic property was
investigated by measuring simultaneously hydrogen concentration depth profiles and
optical absorption in tungsten oxide films.
     The tungsten oxide layer with thickness of 100-400 nm was prepared on C, Si and
SiO2 substrates at a temperature between 300 and 600 K by RF magnetron sputtering
with a pure metal W target in a mixture of argon and oxygen gas, and by pulsed laser
deposition with WO3 target. The structure and morphology of the films were examined
by X-ray diffraction and scanning electron microscope. The hydrogen concentration in
the film was determined by ion beam analysis techniques. The colorating and bleaching
effects were observed in amorphous and oriented crystalline films with relatively large
amount of hydrogen; the excellent gasochromic properties were found in the HxWO3
films with value of x about 0.8, while poorer coloration was observed in the films with
less hydrogen. Under hydrogen exposure, the hydrogen concentration in the film
increased with increasing the optical absorption in the wavelengths of 600 – 1000 nm.
                                         O – 44




           Hydrogen Storage and Delivery Using Liquid Carriers
      Guido Pez, Alan Cooper, Aaron Scott, Michael Ford, Bernard Toseland, and
                                  Hansong Cheng;
       Materials Research Center, Air Products and Chemicals Inc., Allentown,
                                      Pa 18195
                          E-mail: pezgp@airproducts.com


In our concept of a “non gaseous hydrogen” infrastructure the carrier is an organic liquid
which can undergo a reversible catalytic addition of hydrogen. The thus “loaded” liquid
can be catalytically dehydrogenated at the point of use for providing hydrogen at either a
stationary or mobile location. The concept will be illustrated by the performance of N-
and O-heterocyclic molecule carriers. The catalytic dehydrogenation reaction with
present carriers requires an input of heat at temperatures of 150 – 200 °C which may be
difficult to realize with PEM fuel cells. To address this we’ve developed the concept of
autothermal liquid carriers, compositions that in appropriate dehydrogenation reactor
systems could provide both the stored hydrogen and the thermal energy that is required to
liberate it.
                                          O – 45




               Hydrogen Storage Materials - Playing the Odds

      W I F Davida,b, M O Jonesb, M Sommarivaa, S R Johnsonb and P P Edwardsb
      ISIS Facility, Rutherford Appleton Laboratory, Chilton, OX11 0QX, UK and
         Inorganic Chemistry Laboratory, South Parks , Oxford, OX1 3QR, UK
                               e-mail: bill.david@rl.ac.uk


     This talk focuses on our recent studies of novel lightweight hydrides drawn from a
combination of the first four “odd” elements, H, Li, B and N. There is an enormous
variety of hydrides formed solely from a combination of these four elements. This talk
will highlight the strategies that we have adopted to undertake a combinatorial search of
lightweight hydrides with a particular focus on high resolution X-ray and neutron powder
diffraction that play a central role in both the discovery and characterisation of these new
materials.
     High resolution synchrotron X-ray diffraction has been performed on the ID31
diffractometer at the ESRF, Grenoble. Our experiments fall into two different classes: (i)
rapid combinatorial screening of hydride phase diagrams and (ii) in-situ studies of both
the synthesis and decomposition of novel hydrides. Examples will be presented that
illustrate both these approaches and show how both structural and microstructural
information may be extracted that reveal the atomic nature of hydrogen absorption and
desorption.
     Our neutron diffraction studies have been performed on the GEM and HRPD
diffractometers at the spallation neutron source, ISIS, at the Rutherford Appleton
Laboratory. Again our experiments fall into two categories: firstly, the detailed structural
characterisation of novel hydrides, including the accurate determination of hydrogen
positions and secondly simultaneous neutron diffraction and gravimetric analysis using a
specially adapted HIDEN IGA apparatus in-situ on both the GEM and HRPD beamlines.
Preliminary results from experiments will be presented that highlight the power of these
combined measurements.
                                         O – 46




    Probing Structure, Bonding, and Dynamics in Hydrogen-Storage
             Materials by Neutron-Scattering Techniques
                               Terrence J. Udovic
NIST Center for Neutron Research, National Institute of Standards and Technology, 100
             Bureau Dr., MS 6102, Gaithersburg, MD 20899-6102 USA


The novel properties of the neutron, such as its large scattering cross section for
hydrogen, can be routinely exploited by a variety of experimental neutron methods in
order to probe the amount, location, bonding states, and motion of hydrogen in any
promising hydrogen-storage material. For example, neutron powder diffraction (NPD) is
critical for probing the structural details of hydrogen-storage materials and locating the
positions of the absorbed hydrogen atoms and/or molecules. Neutron vibrational
spectroscopy (NVS) complements NPD structural studies by revealing the local bonding
potentials of the absorbed hydrogen. Quasielastic neutron scattering (QENS) provides
molecular-scale spatial and temporal (10-8-10-14s) information simultaneously on
diffusive motions of hydrogen in hydrogen-storage materials, and as such, provides
valuable insights about the molecular-scale geometry and timescale of the diffusion
mechanism. The results of various neutron-scattering measurements can, in turn, be used
to validate the fundamental physical description resulting from first-principles
computational methods and thus deepen our overall understanding of the technologically
important materials properties. This talk will provide recent examples of combined
neutron and computational studies of new hydrogen-storage materials performed at the
NIST Center for Neutron Research, including destabilized light-metal hydrides and
metal-organic-framework structures.
                                         O – 47



                Thermodynamics of Doped Complex Metal Hydrides

          J. Karl Johnson1,2, Sudhakar V. Alapati3, Bing Dai1, David S. Sholl2,3
             1
               Department. of Chemical Engineering, University of Pittsburgh,
                               Pittsburgh, PA 15261, USA
                        2
                          National Energy Technology Laboratory
                                   Pittsburgh, PA 15236
          3
            Department. of Chemical Engineering, Carnegie Mellon University,
                               Pittsburgh, PA 15213, USA
                                  E-mail: karlj@pitt.edu


     Several complex metal hydrides have been proposed as hydrogen storage materials
because of their high gravimetric and volumetric densities. One of the main problems
with these materials is that they are either too stable, requiring unacceptably high
temperatures to release the hydrogen, or not stable enough, releasing hydrogen at low
temperatures or being difficult to rehydride. The reaction enthalpy of metal hydrides may
be tuned by doping the materials with elements that can form compounds in both the
hydrided and dehydrogenated states. A properly chosen dopant can either decrease the
reaction enthalpy, making the dehydrogenated state more favorable, or increase the
enthalpy, favoring the hydrogenated state. We have used first principles density
functional theory to estimate the free energies of various doped metal hydride systems.
We have evaluated the zero temperature enthalpies, without inclusion of zero point
energies, for 18 different doped systems. Most systems are found to be unstable with
respect to phase separation at 0 K. We have included configurational entropy to estimate
the temperature at which the doped systems become stable. Most doped compounds are
estimated to remain unstable with respect to phase segregation up to temperatures that are
too high to be of practical interest. We have identified one system that is stable with
respect to phase segregation at T > 435 K when phonon density of states are included in
the calculations. We have computed the van’t Hoff plot for Sc7H16Ti + 16 LiBH4
Sc7B16Ti + 16 LiH + 32 H2 and compared this to the undoped reaction. Doping increases
the vapor pressure at a given temperature, but only by a factor of 2 to 4. We have also
computed several different candidate structures for Mg(BH4)2 and have compared the
energies and computed XRD structures to the complex structure recently identified
experimentally. We examine the possibility of doping this material and discuss
limitations of using density functional theory for computing the thermodynamics of
doping of such complex structures.
   ABSTRACTS OF
CONTRIBUTED PAPERS




  POSTER SESSION – I

MONDAY, NOVEMBER 12

    8:00 – 10:00 PM
                                          M–1




     Nanostructuring Impact on the Enthalpy of Formation of Metal Hydrides

             Vincent Bérubé, Gregg Radtke, Millie Dresselhaus, Gang Chen
                        Massachusetts Institute of Technology
                                  vberube@mit.edu


Metal and complex hydrides offer very promising prospects for hydrogen storage that
reach the DOE targets for 2015. However, slow sorption kinetics and high release
temperature must be addressed to make automotive applications feasible. Reducing the
enthalpy of formation by destabilizing the hydride reduces the heat released during the
hydrogenation phase and conversely allows desorption at a lower temperature. High-
energy ball milling has been shown to decrease the release temperature, increase reaction
kinetics and lower the enthalpy of formation in certain cases. Increased surface and grain
boundary energy could play a role in reducing the enthalpy of formation, but the
predicted magnitude is too small to account for experimental observations. As the
particle and grain sizes are reduced considerably under high-energy treatments, structural
defects and deformations are introduced. These regions can be characterized by an
excess volume due to deformations in the lattice structure, and have a significant effect
on the material properties of the hydride. We propose the use of two thermodynamic
models to characterize the excess energy present in the deformed regions. The equations
of state (EOS) provided by the models are used to explain the change in physical
properties of metal hydrides. Particularly, the EOSs can predict which hydrides will be
the most destabilized (if destabilized at all) by the introduction of excess volume regions.
The EOSs is compared to density functional theory calculations at zero temperature for
Mg and MgH2 to determine the range of excess volume over which they accurately
predict the energy change. We also investigated the effect of lattice defects on the
dehydrogenation temperature of MgH2 using a TEM equipped with a heating holder. The
TEM allows for real-time imaging of the phase transition accompanying the hydrogen
release as the temperature is increased from room temperature to the hydrogen release
temperature.
                                         M–2




In-situ structural investigation on Pd-assisted hydrogen uptake on activated carbon
                      fibers: Effect of pressure and temperature

               Vinay V. Bhat, Nidia C. Gallego and Cristian I. Contescu
                     Materials Science and Technology Division
              Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA


     In an ongoing DOE Basic Energy Sciences project, ORNL, in collaboration with
Clemson University, is investigating the atomistic mechanisms of metal-assisted
hydrogen storage in nanostructured carbons near ambient temperatures. Our recent
studies on Pd-d activated carbon fibers (Pd-ACF) demonstrate a notable enhancement in
hydrogen storage capacity compared to pure ACF. In addition, Pd-ACF show a peculiar
adsorption behavior, where the adsorption capacity increases with increasing temperature
below 0.4 bar, and the trend reverses when the pressure increases. In order to understand
the role of Pd in this phenomenon, in-situ XRD studies were performed under variable H2
pressure (up to 10 bar) and temperatures (20 to 80 oC), which mimic Pressure-
Composition-Isotherm experiments.
     In this presentation, structural and phase changes in Pd-ACF, ACF and Pd-sponge
will be compared as a function of H2 pressure and temperature. The equilibrium H2 partial
pressure (PEqm) for decomposition of PdHx was determined by calculating the individual
phase concentrations from the diffraction pattern. An enhancement of PEqm in Pd-ACF
compared to Pd-sponge was found, which was correlated to changes in structural
parameters and environment of Pd. The results appear to indicate that destabilization of
PdHx occurred in the ACF environment.
                                         M–3




 Multi-Layered Polymer and Polymer/Metal Structures for Large- and Small-Scale
                        Hydrogen Delivery and Storage

                       James G. Blencoe and Simon L. Marshall
                             Hydrogen Discoveries, Inc.
                          1133-C Oak Ridge Turnpike, #116
                             Oak Ridge, TN 37830, USA

Compressed hydrogen gas can be transferred safely and stored indefinitely in lightweight,
cylindrical or “semi-conformable” structures (narrow-diameter tubes, hoses, pipes and
compartments) furnished/manufactured/built with multi-layered polymer or
polymer/metal walls. Enhanced hydrogen-containment performance arises from two
phenomena that tend to impede diffusive hydrogen flux.

   1. A multi-layered barrier (hydrogen permeation-blocking) material composed of
      one or more materials will have a lower overall hydrogen permeation rate due to a
      phenomenon known as “contact resistance,” a term that refers to a slowing of the
      overall rate of gas permeation at the boundaries between the layers/interlayers of
      the composite material. It is hypothesized that hydrogen diffusive flux at such
      boundaries is slowed by the microstructural discontinuities that occur at the
      interface between each layer in the composite solid material, even when all of the
      layers are composed of the same solid material.
   2. A multi-layered barrier material consisting of one or more layers of one or more
      polymers, and one or more layers of one or more metals or metal alloys with low
      hydrogen permeability, will typically exhibit a much lower overall hydrogen
      permeation rate than single or multi-layered barrier materials that do not contain
      one or more layers of such metal(s) or metal alloy(s). This is due not only to the
      superior performance of the metal(s) or metal alloy(s) in slowing diffusive
      hydrogen flux, but also to a greater contact resistance that results from the
      differences between the atomic states of hydrogen in polymeric and metallic
      materials. In the former, dissolved hydrogen exists in the diatomic state, whereas
      in metals and metal alloys, diatomic hydrogen splits into individual hydrogen
      atoms upon its dissolution in the metal or metal alloy. These different
      mechanisms of dissolution lead to higher contact resistance at the boundaries
      between contiguous polymeric and metallic layers in a composite structure
      because, in addition to encountering microstructural discontinuities at each sharp,
      polymer/metal interface, hydrogen is also forced to switch atomic states in
      passing from the polymer into the metal or metal alloy and vice versa.

Rigorous theoretical modeling of hydrogen permeation through multi-layered polymer
(e.g., HDPE) and polymer/metal tubes indicates that a thin layer of aluminum, copper or
stainless steel will be highly effective in decreasing overall diffusive hydrogen flux.
                                        M–4




               Initiation of Hydrogen Release from Ammonia Borane

  Mark Bowden1, Nancy Hess2, Wendy Shaw2, David Heldebrant2, Scot Rassat2, Tom
                          Autrey2, Tim Kemmitt1, Ian Brown1
         1
           Industrial Research Ltd, PO Box 31-310, Lower Hutt, New Zealand
    2
      Pacific Northwest National Laboratory, P.O. Box 999, Richland, WA 99352
                              E-mail: m.bowden@irl.cri.nz


Ammonia borane (H3NBH3) has been highlighted [1] as one of the leading candidates for
chemical hydrogen storage, partly on account of its high gravimetric hydrogen content
(19.6 wt% H2). A mole equivalent of hydrogen gas may released by heating ammonia
borane to 70-110°C. The kinetics appear to follow a typical solid-state nucleation and
growth mechanism but with a more prolonged induction period than predicted by theory.
We have examined this induction period using a combination of techniques including
solid-state nmr spectroscopy [2], X-ray powder diffraction, optical microscopy and
Raman spectroscopy, all under high temperature conditions. These point to a complex
mechanism involving a mobile, isotropic form of H3NBH3 and the ionic compound
[H3NBH2NH3]+[BH4]- as precursors to hydrogen generation. Activation energies for the
induction process and for the generation of hydrogen have been estimated from Arrhenius
relationships.     Seeding ammonia borane with ionic compounds including
               +
[H3NBH2NH3] [BH4]- eliminates the induction period, consistent with the proposed
mechanism.


   1. F.H. Stephens, V. Pons, R.T. Baker, Dalton Trans., 2007, 2613–2626.
   2. A.C. Stowe, W.J. Shaw, J.C. Linehan, B. Schmid, T. Autrey. Phys. Chem. Chem.
      Phys., 2007, 9, 1831.
                                           M–5




             Dynamical, Structural and Electronic Properties of Li[BH4]

   F. Buchter, Z. Lodziana, A. Remhof, Ph. Mauron, A. Borgshulte, and A. Züttel
 EMPA Materials Sciences and Technology, Überlandstrasse 129, CH-8600 Dübendorf,
                                    Switzerland
                         E-mail: florian.buchter@empa.ch


     Li[BH4] has a gravimetric hydrogen density of 18 mass% and volumetric hydrogen
density of 121 kg m-3 making this compound an interesting candidate for hydrogen
storage. Li[BH4] and most of the alkali complex hydrides only desorb hydrogen after
melting due to either the thermodynamical stability or a kinetic barrier. The key issue, in
order to taylor the temperature and pressure level needed for a reversible storage of
hydrogen to suitable conditions, is to understand the mechanism involved in the
formation/decomposition of these compounds.
     The hydrogen dynamics involves the rearrangement of the Li+ and [BH4]- ions during
the structural transition of the compound at 110°C and the breaking of the ionic bond
between Li+ and [BH4]- ions at the melting of the compound at 280°C. Finally, the
breaking of the covalent B-H bonds within the [BH4]- tetrahedron during the hydrogen
release above 320°C depends on the thermal motion of hydrogen. The disorder of the
structure and the dynamics of hydrogen in both low and high temperature phases of
Li[BH4]/Li[BD4] have been studied. Incoherent inelastic neutron diffraction provides the
phonon density of state of the hydrogen atoms and shows a weakening of the bond
between the Li+ and [BH4]- ions in the transition from low to high temperature phase. The
temperature dependence of the crystal density determined from coherent elastic neutron
diffraction, undergoes a jump at the phase transition, due to increased disorder in the high
temperature phase. Structural properties of Li[BH4] from accurate coherent elastic
neutron diffraction data are compared with the results from ab-initio calculations. In
particular the [BH4]/[BD4] tetrahedral geometry and the thermal motion of the atoms are
compared, with excellent agreement. The experimental determination of the charge
density of the Li[BD4] is done in order to study the charge transfer between the different
atoms within the compounds and compare it with theoretical results. The method
combines neutron diffraction, X-ray diffraction, and maximum entropy method in order
to determine the most probable charge density.
     In conclusion, we found an excellent agreement between our results from ab-initio
calculation and experimental data. In particular, for the description of the disorder, ab-
initio calculation of the rotational energy barriers of a [BH4]- ion within the structure give
a very interesting picture of our experimental observations and a good model for the
disorder observed experimentally. The combination of experimental and theoretical result
provide a better understanding of mechanisms involved in the phase transition and
stability of the Li[BH4]/Li[BD4].
                                          M–6




                   Analysis and Modelling of the Burst Pressure of
                           High Pressure Hydrogen Tanks

                D. Chapelle, F. Thiébaud, D. Perreux, P. Robinet
         LMARC-FEMTO-ST, Université de Franche-Comté, Besançon, France
                        Email : contact@mahytec.com

      The development of hydrogen for energy is depending on several issues. Among
them, performance and safety of hydrogen storage are the most relevant. The high
pressure hydrogen storage HPHS (700 bars) is currently the more efficient technology1.
Then for storage, one of the main breakthrough regards the safety of HPHS.
      To improve the safety, the understanding of the behaviour of tanks under pressure
(static or fatigue loading) is crucial. As a consequence, the development and the
validation of numerical tool to predict the burst pressure is also crucial to design tanks.
The paper is devoted to one of this kind of tools.
      The present paper aims to study the cylindrical section of a high-pressure hydrogen
storage vessel, combining a liner which prevents gas diffusion and an over wrapped
composite devoted to reinforce the structure. Today, this technique is widely used but
still requires consistent time investments whenever a competitive solution, involving to
definitely increase weight efficiency, is needed. The laminate composite is assumed to be
an elasto-damage material whereas the liner behaves as an elasto-plastic material.
      Based on the structural analysis and on Hill’s criterion to take into account the
anisotropic plastic flow of the liner, the model provides an exact solution for stresses and
strains on the cylindrical section of the vessel under thermomechanical static loading.
      The paper is focuses on the theoretical background2. The effect of the stacking
sequence on the gap occurrence, on the residual stress magnitude and on the structure
stiffness may then be investigated. This will be done and be compared with results of
experiments which are carried out on prototypes before a further optimization is
performed.

1 Arindam Sarkar, Rangan Banerjee, Net energy analysis of hydrogen storage options,
International Journal of Hydrogen Energy 30 (2005) 867 – 877
2 David Chapelle, Dominique. Perreux, International Journal of Hydrogen Energy 31
(2006) 627 – 638 Optimal design of a Type 3 hydrogen vessel: PartI—Analytic
modelling of the cylindrical section

Keywords: Material Behaviour, Modelling, Failure criteria, burst test
                                           M–7




  Modeling of Evolution of Temperature inside LaNi 4.78Sn0 .22 storage tank during
                             absorption of Hydrogen

         Nivas Babu. S1,2, D. Chapelle1, D. Perreux1, H. Figiel2, A. Paja2
    1
    LMARC- FEMTO-ST, Universite de Franche Comte- 25000 Besancon, France
2
  AGH – University of Science and Technology Al. Mickiewicza 30, 30-059 Kraków,
                                      Poland
                         E-mail: nivasbabus@yahoo.co.in


     Metal-hydride systems have become a secure and effective way to store hydrogen for
fuel cells and to produce thermodynamic or electrochemical work for stationary and
mobile applications. One of the main advantages of metal hydride system is its
compatibility compared to other storage systems. The main draw back of metal
hydride storage systems could be the kinetics of hydrogen absorption/desorption process,
which is slow in most of the cases, this is because of the dependence of kinetics on
temperature of the material, as temperature inside the material exceeds the limit, the
reaction stops. Lots of efforts had been done to control this disadvantage, one of the way
is to provide a better heat exchanger, another way is to optimize the structure of the
container to improve heat exchange.
     In the second solution modelling of the temperature inside the hydride and the
container is a powerful tool to understand the problem and to improve the knowledge of
the temperature profile in the tank during absorption.
     This work presents a systematic approach for modelling the temperature of tank
during filling. A detailed mathematical model is developed, based on the amount of
temperature generated during hydrogen absorption by metal hydride and on an assumed
profile in time to describe kinetics. This profile is mainly depending on the heat capacity
of the material (Intermetallic+hydride+hydrogen) during the reaction. This model is
implemented in a finite difference software. This software provides the way to optimise
the dimension of the container. . In application we especially discuss the case of
LaNi4.78Sn0 .22
     This model provides significant insight into the problem of heat exchange and a first
hand information about the temperature at the surface of the tank at different time, which
allows to design the container.

[1] Momirlan M, Veziroglu TN. Current status of hydrogen energy. Renewable Sustainable
Energy Rev 2002; 6:141–79.
[2] Mohanty KK. The near-term energy challenge. AIChE J 2003;49(10):2454–60.
[3] Kaplan Y, Veziroglou TN. Mathematical modelling of hydrogen storage in LaNi5 hydride
bed. Int J Hydrogen Energy2003; 27:1027–38.
[4] Sandrock G, Bowman Jr. RC. Gas-based hydride applications: recent progress and future
needs. J Alloys Compd 2003; 356–357:794–9.
[5] Eberle U, Arnold G, von Helmolt R. Hydrogen storage in metal-hydrogen systems and their
derivatives. J Power Sources 2006; 154:456–60.
                                               M–8




   Modification of Hydrogen Desorption from Amide–Borohydrides and Related
                                  Materials

                Philip A. Chater, Ian C. Evans and Paul A. Anderson
School of Chemistry, The University of Birmingham, Edgbaston, Birmingham UK B15 2TT.
                         E-mail: p.a.anderson@bham.ac.uk.


In the search for hydrogen storage materials containing a large percentage of hydrogen by
weight, systems based on amides, borohydrides and ammonia-borane are amongst the
most intensively researched [1]. We have synthesized a number of new light metal
complex hydrides (Ref. [2] and Fig. 1) with some of the largest hydrogen capacities
known. Thermally induced hydrogen desorption has been demonstrated from all of these
compounds, with temperatures of desorption that vary widely from below 100°C to above
250°C [3]. Here we report an investigation into the effect of alkali and alkaline earth
metal hydrides on hydrogen desorption in these systems. Reductions in the
decomposition temperature of up to 40°C (Fig. 2) were observed and in at least one case
the hydrogen desorption was found to be partly reversible. The complex chemistry of the
processes involved will be discussed.




  Fig. 1. Crystal structure of a new lithium    Fig. 2. Hydrogen desorption from a lithium
       amide–borohydride compound.             amide-borohydride compound (a) with and (b)
                                                 without the presence of a metal hydride.

[1] P. Chen et al., Nature, 2002, 420, 302; A. Züttel et al., J. Power Sources, 2003, 118,
1; F. Baitalow et al., Thermochim. Acta, 2002, 391, 159.
[2] P. A. Chater, W. I. F. David, S. R. Johnson, P. P. Edwards and P. A. Anderson,
Chem. Commun., 2006, 23, 2439.
[3] P. A. Chater, P. A. Anderson, J. W. Prendergast, A. Walton, V. S. J. Mann, D. Book,
W. I. F. David, S. R. Johnson and P. P. Edwards, J. Alloys Compd., 2007,
doi:10.1016/j.jallcom.2007.01.114.
                                      M–9




              Role of catalysts in the regeneration of LiBH4-MgH2
                 1*
                   Santanu Chaudhuri, 2Alex Ignatov, 3Jason Graetz
 1
     Applied Sciences Laboratory, Washington State University, WA 99210-1405,
       2
         Chemistry Department, Louisiana State University, Baton Rouge, LA
                3
                  Brookhaven National Laboratory, Upton, NY 11973
                           *
                             E-mail:chaudhuri@wsu.edu


The LiBH4-MgH2 mixture can demonstrate hydrogen storage capacity of 11.4 wt%
H2.1, 2 The LiBH4 and MgH2 are both well studied as H2 storage material, and have
their respective hurdles in effective regeneration. Although this material showed
certain thermodynamic advantage through destabilization, the regeneration process
takes as long as 2 h at 300oC and hydrogen pressure of 100 bar.1 Improvement of
regeneration kinetics is thus of prime importance for this material to satisfy system
targets set by DOE. The current work explores the possible role played by Ti as a
catalyst using first principles techniques and combines experimental data from FT-
EXAFS. The regeneration process requires efficient chemisorption of hydrogen in the
MgB2 formed when LiBH4-MgB2 is dehydrided. We have explored the role of
catalytic chemisorption of molecular hydrogen in MgB2. The chemistry of MgB2 is
similar to the other layered-structure materials. Their reactions are often dominated
by intercalations, inter-layer hopping and diffusion of adsorbed gases (such as H2)
through these honeycomb pores and interlayer spaces. We will present results that
show that the MgB2 is similar to other members of this family. The interlayer spacing
and the doping of catalysts in the cationic (Mg2+) and anionic layers (B-layers) holds
lot of importance in improving the kinetics of hydrogen storage reactions. We will
discuss: (a) H2 chemisorption barriers on both doped and undoped Mg-and B-
terminated terminated MgB2 surfaces, and (b) use Ti as a model catalyst to
demonstrate the role it plays by means of changing inter-layers spacing and the
chemisorption barriers. The thermodynamic and kinetic models presented for this
reaction combined with the role of borane clusters opens up a range of possibilities
that can make LiBH4-MgH2 a strong contender for a practical use.


1. Vajo, J. J.; Skeith, S. L.; Mertens, F., Reversible storage of hydrogen in
destabilized LiBH4. Journal of Physical Chemistry B 2005, 109, (9), 3719-3722.
2. Vajo, J. J.; Skeith, S. L.; Mertens, F.; Jorgensen, S. W., Hydrogen-generating
solid-state hydride/hydroxide reactions. Journal of Alloys and Compounds 2005, 390,
(1-2), 55-61.
                                        M - 10




First Principles Study of Interaction of Molecular Hydrogen with Li Doped Carbon
                                    Nano Peapod

               L. Chen1, Y. Zhang1, N. Koratkar2, P. Jena3, and S. K. Nayak1
    1
      Department of Physics, Applied Physics and Astronomy, Rensselaer Polytechnic
                                Institute, Troy, NY 12180
         2
           Mechanical Engineering Department, Rensselaer Polytechnic Institute,
                                     Troy, NY 12180
            3
              Physics Department, Virginia Commonwealth University, Richmond,
                                         VA 23284
                                      chenl@rpi.edu


Using first principles density functional theory based on gradient corrected approach we
have studied interaction of H2 molecule with Li doped carbon nanotube and nanotube
based peapod structures. In agreement with earlier study we find that H2 physisorbs on
pure carbon nanotube while the binding increases when H2 binds to Li atoms decorated
on carbon nanotube surfaces: the binding is further enhanced with Li atoms deposited on
C60 doped nanotube peapod structures. The increase in binding in the latter structures
arises due to charge transfer between the nanotube and C60 which further facilitates
charge transfer from Li to the nanotube. Encapsulating fullerene molecule inside the
nanotube provides a new way of increasing charge concentration on Li atom adsorbed
outside the nanotube. The increase in H2 binding energy due to C60 encapsulation,
compared to recently engineered metal doped nanotube structures, may lead to new
carbon based materials for hydrogen storage at room temperature.
                                          M – 11




Study on the Structure and Electrochemical Properties of Novel Nd-Mg-Ni-Co Hydrogen
                                    Storage Alloys

                              Pan Chongchao, Yu Ronghai
Department of Materials Science & Engineering, Tsinghua University, Beijing 100084, China




    Nd0.75Mg0.25 Ni0.8Co0.2 x (x=3.8 4.5) hydrogen storage alloys have been
prepared by mid-frequency induction melting furnace. The structure analyses and
electrochemical properties of the alloys were investigated by means of XRD, TEM and
electrochemical workstation, the results showed that the alloy consists of Ce2Ni7 type
Nd2Ni7 super-structure and CaCu5 type NdNi5 structure. The main phase of alloy
belongs to Ce2Ni7 type Nd2Ni7 super-structure when x is 3.8, Mg atoms are located only
at the Laves unit of Ce2Ni7 type unit cell, while Co atoms are located only at the CaCu5
unit. What is more, magnetization treatment improves the high-rate discharge capacity
and cycling life of the alloys. Electrochemical analyses showed that all the alloys have a
large discharge capacity and can be easily activated.
The Nd0.75Mg0.25 Ni0.8Co0.2 3.8 alloy exhibits better electrochemical properties.

Keywords: Hydrogen storage alloys; Super-structure; Electrochemical properties

Corresponding author. Tel.:+86-010-62772620
E-mail address: pcc05@mails.tsinghua.edu.cn
                                         M – 12




  A Thin-Film Nanocalorimetry Approach to the Evaluation of Hydrogen Storage
                  Materials, with Combinatorial Possibilities

   L. P. Cook, R. E. Cavicchi, M. L. Green, W. F. Egelhoff, C. B. Montgomery, and
                                      P. K. Schenck,
       National Institute of Standards and Technology, Gaithersburg, MD 20899
                             E-mail: lawrence.cook@nist.gov


Both thermodynamic ( Hr) and kinetic (Eactivation) parameters are an important part of
evaluating the absorption/desorption properties of hydrogen storage materials.
Nanocalorimetry provides a rapid, relatively low-cost means of screening materials for
their hydrogen storage potential, by enabling measurement of Hr and Eactivation. For this
purpose, we apply a MEMS-type differential scanning nanocalorimeter with sensor area
of 66 m x 100 m, and a demonstrated sensitivity of < 100 nJ. In the current design,
chips are fabricated with six DSC (differential scanning calorimeter) sensors per chip,
giving multiple measurement capability. Each DSC sensor is positioned on a back-
etched platform which is suspended only by thin supports, resulting in minimal
conductive loss to the chip. Maximum temperature of the sensors is 540 °C, which we
have attained in H2 ambients ranging from 6E-4 Pa to 1E+5 Pa. A typical experimental
sequence includes: 1) charging the sample at 25 °C under a fixed hydrogen pressure
(1E+5 Pa to 5E+5 Pa); 2) evacuating and backfilling with inert gas; 3) ramping the DSC
temperature to observe Hr of hydrogen desorption; 4) optical observation of sample
during the ramp; 5) repeating the experiments to verify reproducibility; 6) repeating the
experiments at different scan rates to determine Eactivation. Many other experiments can be
designed, including isothermal hydrogen absorption experiments to obtain additional
kinetic information, and ramping at various hydrogen pressures to determine Kequilibrium.
We are currently evaluating the thin-film nanocalorimetric approach with known
materials, including LaNi5, FeTi, and Pd. A goal for future research is the design and
construction of dense arrays of small nanocalorimeter devices that would enable
combinatorial applications.
                                               M – 13




    Calcium Ammonia-borane, Ca(NH2BH3)2: A Promising Hydrogen Storage
                                Material

 Himashinie V. K. Diyabalanage, Roshan P. Shrestha, Troy A. Semelsberger, Brian L.
                  Scott, Benjamin L. Davis and Anthony K. Burrell
Materials Chemistry, Materials Physics and Applications Division Los Alamos National
              Laboratory Mail Stop J514, Los Alamos NM 87545, USA
                                himashinie@lanl.gov


Among the potential candidates for effective chemical hydrogen storage ammonia-borane
(NH3BH3) garnered much interest due to it’s high hydrogen storage capacity of 19.6 wt%
and low molecular weight, which are ideal features for hydrogen storage material. Even
though ammonia-borane has a high molecular hydrogen storage capacity, only 2/3 of this
hydrogen is readily accessible. The modification of ammonia-borane is desirable to
improve many of the properties of this promising hydrogen storage material. We have
undertaken a systematic study of ammonia-borane derivatives that can quickly release the
hydrogen and be reprocessed using hydrogen pressure. The materials we have prepared
are derivatives of ammonia-borane where a new covalent bond between the nitrogen and
a metal or main group element, has been formed. For instance, the reaction of NH3BH3
and calcium hydride in THF leads to the corresponding calcium(II)ammonia-borane
derivative as a bis-THF adduct, in excellent yield which loses THF once removed from
solution giving Ca(NH2BH3)2.




             X-ray crystal structure & the packing diagram of bis-THF adduct of Ca(NH2BH3)2

This material has significantly different thermal properties than ammonia-borane. It
undergoes loss of H2 without significant foaming, a common problem associated with
solid NH3BH3 and offers several advantages over NH3BH3 including better thermal
stability and more controlled hydrogen release over a wider temperature range.
                                         M – 14




            Mechanochemistry of the MNH2-MgH2 Systems (M=Li or Na)

                      O. Dolotko, H. Zhang, V.K. Pecharsky,
  Ames Laboratory and Department of Materials Science and Engineering, Iowa State
          University, Ames, IA 50011-3020, USA, dolotko@ameslab.gov


     Mechanochemical reactions between alkali metal amides and magnesium hydride
taken in 2:3 and 1:1 molar ratios have been investigated. High levels of hydrogen release
have been observed during the high energy ball milling of the mixtures at room
temperature without adding any catalysts or solvents.
     Analysis of the products showed formation of magnesium nitride, alkali metal
hydrides and pure hydrogen during the high energy ball milling of the mixtures taken in
2:3 molar ratio of components. Amount of released hydrogen is 6.5 wt.% for 2LiNH2-
3MgH2 system (18h ball milling) and 5.1 wt.% for 2NaNH2-3MgH2 system (9h ball
milling). An intermediate phase with the cubic face-centered structure and lattice constant
a=4.407(4)Å forms in both systems after 3h of ball milling. This compound can not be
assigned to any known phase composed of Mg, Li, N, H or any combination of these
elements. Likely formula of this new intermediate phase is MgNH. Thus, the reaction that
occurs during the ball milling of 2 moles MNH2 with 3 moles MgH2, where M is Li or
Na, proceeds in two steps. In the first step, MNH2 reacts with MgH2 to form “MgNH”
with hydrogen release. The intermediate “MgNH” then reacts with excess MgH2 to yield
Mg3N2, releasing more gaseous hydrogen. The overall reaction can be presented as R1:

2MNH2(s) + 3MgH2(s)        Mg3N2(s) + 2MH + 4H2(g)↑                        (R1)

A detailed examination of the solid state mechanochemical transformation of LiNH2 and
MgH2 taken in a 1:1 molar ratio shows formation of known Li2Mg(NH2) and Mg3N2
compounds as a final products. A total of 6.1 wt.% of hydrogen is released by this system
after 6h of ball milling. The overall mechanochemical transformation during the ball
milling of the 1LiNH2-1MgH2 system proceeds according to R2:

4LiNH2(s) + 4MgH2(s)       Li2Mg(NH2)(s) + Mg3N2(s) + 2LiH + 3H2(g)↑ (R2)

Acknowledgement: This work has been supported by the Office of Basic Energy
Sciences, Materials Sciences Division of the US Department of Energy under Contract
No. DE-AC02-07CH11358 with Iowa State University.
                                         M – 15




Chemical Hydrogen Storage beyond NBHx: Improving Thermodynamics, Exploring
                            Hierarchical Storage

           Michael J. Edie,a Alexander V. Abramov, a Jun Li ,b Maciej Gutowskia
    a
      Heriot-Watt Unviersity, Chemistry-School of Engineering and Physical Sciences,
                          Edinburgh EH14 4AS, United Kingdom
b
  W. R. Wiley Environmental Molecular Sciences Laboratory, Pacific Northwest National
                          Laboratory, Richland, WA 99352, USA


     Boron-nitrogen hydride (BNHx) materials display promising gravimetric and
volumetric densities of hydrogen. Hydrogen release from various forms of (BNHx)
compounds is typically slightly exothermic and regeneration of the spent materials is
challenging. Different approaches aiming at improved thermodynamics are being
pursued. We recognize that the BN unit is isoelectronic with the CC unit and
dehydrogenation of hydrocarbons is typically endothermic. Thus we propose that (BN)(1-
y)C2yHx compounds might display thermodynamics for dehydrogenation intermediate
between this for carbon-based and that for BN-based hydrides. We will present promising
computational results for molecular and extended (BN)(1-y)C2yHx compounds.
     The following effort aims at improving gravimetric density of hydrogen and kinetics
of hydrogen release. We envision clathrates loaded with molecular hydrogen, in which
the clathrate cages are built from a material that is a hydrogen storage medium per se.
These loaded clathrates would have hydrogen stored at two levels: (i) molecular
hydrogen weakly bound in clathrates, thus kinetically easily accessible, and (ii) hydrogen
chemically stored in the clathrate framework, thus kinetically less accessible but critical
for the total gravimetric density of hydrogen. The proposed concept is an improvement
over clathrate hydrates loaded with molecular hydrogen, as the latter are stable only at
relatively low temperatures/high pressures, and the gravimetric density of accessible
hydrogen is low. We propose to replace water with a material, which (i) forms stronger
hydrogen bonds than water, (ii) binds H2 stronger than H2O, and (iii) may be viewed as
thermodynamically and kinetically viable hydrogen storage medium. We will report
computational results on clathrate structures based on ammonia borane, NH3BH3, in
which intermolecular dihydrogen bonds stabilize the framework. The effect of loading
with molecular hydrogen will be discussed.
                                         M – 16




  Indirect, Reversible High-Density Hydrogen Storage in Compact Metal Ammine
                                      Salts

Jens Strabo Hummelshøja, Rasmus Zink Sørensenb, Asbjørn Klerkeb, Jacob Birke Revesb,
            Tejs Veggec, Jens Kehlet Nørskova and Claus Hviid Christensenb
   a
      Center for Atomic-scale Materials Design, Department of Physics, Building 310,
            Technical University of Denmark, DK-2800 Kgs. Lyngby, Denmark.
 b
    Center for Sustainable and Green Chemistry, Department of Chemistry, Building 206,
            Technical University of Denmark, DK-2800 Kgs. Lyngby, Denmark.
  c
    Materials Research Department, Risø National Laboratory, NanoDTU, Building 228,
              Technical University of Denmark, DK-4000 Roskilde, Denmark.
                                    strabo@fysik.dtu.dk


     The indirect hydrogen storage capabilities of Mg(NH3)6Cl2, Mn(NH3)6Cl2,
Ni(NH3)6Cl2 and Ca(NH3)8Cl2 are investigated. All four metal ammine chlorides can be
compacted to solid tablets with densities at least 95% of the crystal density giving very
high indirect hydrogen densities both gravimetrically and volumetrically. Upon heating,
NH3 is released from the salts and by employing an appropriate catalyst, H2 can be
released corresponding to up to 9.78 wt%H and 0.116 kgH/L for the Ca(NH3)8Cl2 salt.
The NH3 release from all four salts is investigated using different heating rates and
desorption is found to be limited mainly by heat transfer. During desorption from solid
tablets of Mg(NH3)6Cl2, Mn(NH3)6Cl2 and Ni(NH3)6Cl2, a nano-porous structure
develops, which facilitates desorption from the interior of large compact tablets.
     Density functional theory calculations are used to calculate desorption enthalpies for
ammonia release from Mg(NH3)6Cl2, Mn(NH3)6Cl2, Ni(NH3)6Cl2 and Ca(NH3)8Cl2, and
to understand the details underlying the fast ab/desorption processes. The calculated
desorption enthalpies agree qualitatively with the experimental results in a model which
compares stable structure energies, and quantitatively in a model where chains of the
material are ripped from the surface and emptied from ammonia. The latter model also
explains the fast ab/desorption processes.
                                         M – 17




            Storage of Compressed Hydrogen in Multi-Capillary Arrays

                                   N. K. Zhevago
        Russian Research Centre “Kurchatov Institute”, Moscow 123182, Russia
                              nick_zhevago@tochka.ru

                                      Dan Eliezer
              Ben Gurion University of the Negev Beer Sheva 84105, Israel
                                  deliezer@bgu.ac.il


     Hydrogen storage is a key issue in the success and realization of hydrogen
technology and economy. Since the conventional hydrogen fuel storage methods of
pressuring H2 gas and cryogenic liquid H2 pose safety and permeation problem along
with high cost, they do not meet future on-board applications goals set for hydrogen
economy. Solid state hydrogen fuel storage either absorption in the interstices of metals
and metallic alloys or adsorption on high surface area materials such as activated carbon
gain the attention for possible future hydrogen applications. There is no perfect choice of
hydrogen store material to meet the set US DOE goals for transport application. The
success and realization of hydrogen economy using hydrogen stored solid fuel
technology will be dependent on the meeting of above goals.
     The present paper describes a novel method of hydrogen storage in the array of
sealed capillaries made of various materials. The suggested method ensures more safety
compared to usual tanks. Theoretical estimates show that using thin enough capillaries of
quartz, aramids or other materials with low specific weight to tensile strength ratio it is
possible to achieve or even surpass the DOE 2010 demands for the gravimetric and
volumetric capacity of the storage medium [1,2]. The different ways of refilling
capillaries with compressed hydrogen: permeation through the walls of primarily sealed
capillaries at elevated temperature and sealing of capillaries with metal alloys after
pumping hydrogen inside through the open end will be discussed in details. The
theoretical analysis of the resistance of the capillary arrays of the hydrogen pressure of
hydrogen loading and releasing will be presented.


 [1] V. G. Gnedenko, I. V.Goryachev, N. K. Zhevago "Apparatus for storage of
compressed hydrogen gas", U.S. Provisional Patent Application No 60/752,379
[2] N.K. Zhevago, V.I. Glebov, Energy Conversion and Management 48 (2007) 1554–
1559
                                        M – 18




   Properties of Novel Deuterides Synthesized in Gas-Solid Reaction under High
                               Deuterium Pressure
  *
    S. M. Filipek1, V. Paul-Boncour2, R. S. Liu3, A. Balaprasad3, H. Sugiura4, H. D.
                                    Yang5, R. Wierzbicki1
      1
        Institute of Physical Chemistry, Polish Academy of Sciences, Warsaw, Poland.
   2
     Institut des Sciences Chimiques Seine-Amont, Laboratory, CNRS, Thiais, France.
       3
         Department of Chemistry, National Taiwan Univ., Taipei, Taiwan 106, ROC.
         4
           Graduate School of Integrated Sci., Yokohama City Univ.,Yokohama Japan
   5
     Dept. of Physics, National Sun Yat-Sen University, Kaoshiung 804, Taiwan, ROC
                                   E-mail: smf@ichf.edu.pl


High temperature treatment of Laves phases under high deuterium pressure resulted in
syntheses of number of interesting novel hydrides (deuterides) [1-4]. The ErFe2D5 or
YFe2D5 [1-3] derived from C15 Laves and YMn2D6 or ErMn2D6 [4] formed from C15
type YMn2 or C14 type ErMn2 belong to these novel deuterides. It was revealed that
some of these compounds have unexpectedly good stability. Structures of ErFe2D5 and
YFe2D5 [1,3] were refined in a centered orthorhombic Imm2 space group while YMn2D6,
ErMn2D6 [4] and some other RMn2D6 (R – rare earth) have cubic Fm-3m structure.
Following these findings we started a systematic investigation of pseudobinary Laves
alloys R(MnxFe1-x)2 under high deuterium pressure. Structural and magnetic properties of
resulted R(MnxFe1-x)2Dx deuterides are reported, including their behaviour under high
hydrostatic pressures. Studies of distribution of iron and manganese in the R(MnxFe1-
x)2D6 lattice can help to understand the mechanism responsible for transitions of C14 or
C15 RMn2 Laves into the Fm-3m RMn2D6 stimulated by high deuterium (or hydrogen)
pressure.


[1] V. Paul-Boncour, S.M. Filipek, A. Percheron-Guegan, I. Marchuk, J. Pielaszek,
Journ. Alloys Comp., 317-318 (2001) 83-87.
[2] S.M. Filipek, V. Paul-Boncour, A. Percheron Guegan, I. Jacob, I. Marchuk, M.
Dorogova, T. Hirata, Z. Kaszkur, J.Phys, Cond.Matter, 14 (44) 11261 (2002).
[3] V. Paul-Boncour, S.M. Filipek, I. Marchuk, G. Andre, F. Bouree, G. Wiesinger, A.
Percheron-Guegan, J.Phys.; Condens. Matter 15 (2003) 4349-4359.
[4] V Paul-Boncour, S M Filipek, G André, F Bourée, M Guillot, R Wierzbicki, I
Marchuk, R S Liu, B Villeroy, A Percheron-Guégan, H.D. Yang, S. C. Pin, J.Phys.:
Condens. Matter 18 (2006), 6409.
                                            M – 19




     A First Principles Study of Transition Metal Interaction with NaAlH4 (001)

                            Jianjun Liu and Qingfeng Ge
 Department of Chemistry and Biochemistry, Southern Illinois University, 1245 Lincoln
                          Drive, Carbondale, Illinois 62901
                              Email: qge@chem.siu.edu


Periodic density function theory calculations with PAW potentials and plane-wave basis set
have been carried out to investigate the stability and hydrogen desorption energies of 3d
transition metal-doped NaAlH4 (001) surfaces. A TMAl3H12 complex structure in which the
transition metal atom occupies interstitial position of three AlH4- units has been identified to
be the most stable structure for all 3d transition metal elements except for Ni. According to
18-electron rule, the TMAl3H12 complex formed with transition metal elements Sc to V, Cr,
and Mn to Ni can be classified as electron-deficient, electron-neutral, and electron-rich,
respectively. Correlation of the binding energy of TM in the complex as well as the hydrogen
desorption energies from the complex to 18-electron rule has been explored. In the electron-
deficient TMAl3Hx complexes, the central TM atom is a strong attractive center for the
surrounding Al-H and H—H. Once enough Al-H and H—H bonds were attached to the TM
center in the TMAl3Hx complex, an electron-rich state can be achieved. On the other hand, the
TM center will return to the electron-deficient state by releasing the Al—H and H—H from
the complex, i.e. desorbing hydrogen. We speculate that the cycle between electron-deficient
and electron-rich state makes the TM centered TMAl3Hx an active species in
dehydrogenation and re-hydrogenation of NaAlH4.
                                         M – 20




  Photoelectron Spectroscopy of AlmHn-: From borane-resembling closo-alanes to
             shell-model obeying hydrogen-doped aluminum clusters

                    A. Grubisic, X. Li, S. T. Stokes, K. H. Bowen
      Johns Hopkins University, Baltimore MD, USA (Email: agrubisic@jhu.edu)
                                    G. F. Ganteför
                    University of Konstanz, Konstanz, Germany
                                  B. Kiran, P. Jena
              Virginia Commonwealth University, Richmond VA, USA
                            R. Burgert, H.-G. Schnöckel
                    University of Karlsruhe, Karlsruhe, Germany


     A combination of photoelectron spectroscopic studies and DFT calculations has been
conducted on aluminum hydride cluster anions, AlmHn- (4 m 13, 0 n 10). Large
HOMO-LUMO gaps (0.5 – 1.9 eV) of species with stoichiometry AlnHn+2- indicate
enhanced stability of their corresponding neutrals, AlnHn+2, relative to those of their
stoichiometric neighbors and have been shown to adopt structures similar to those of
closo-boranes. Similarly to boranes, hydrogen in these alanes is observed to bond either
via a localized terminal bond to a single aluminum atom (Al-H) or via a delocalized 3c-
2e (three-centered-two-electron) bond to two neighboring aluminum atoms (Al/H\Al).
For electron counting purposes, an electron is effectively removed from the aluminum
core in the former case, but donated to the cage by hydrogen in the latter case. The choice
of the site is observed to generally follow Wade-Mingos rules in the hydrogen-rich
species (m < n) and the Jellium shell model in the aluminum-rich species (m > n). The
variety of bonds hydrogen can form with the aluminum cluster may allow for tunability
of hydrogen detachment energies with cluster composition via hydrogen atom’s choice of
different binding sites in the cluster.
     With currently limited sources of materials with sufficiently high gravimetric
hydrogen content (i.e. LiAlH4) that would simultaneously show satisfactory near-ambient
hydrogen desorption kinetics and great degree of reversibility, several in our work
identified, promising building blocks for potential hydrogen storage cluster-assembled
materials may offer a much needed compromise between the mutually exclusive demands
of industry for feasibility of the hydrogen economy.
                                             M – 21




    Hydriding behaviour of Mg-x wt% ZrCrMn composites prepared by high energy
                                   ball milling

               Ankur Jaina,b,*, P. Gislona, A. Mascia, I.P. Jainb, P. P. Prosinia,*
a
    Centre for Non-Conventional Energy Resources, University of Rajasthan, Jaipur, India.
 b
     ENEA-IDROCOMB, C.R. Casaccia, Via Anguillarese 301, 00060 S. Maria di Galeria,
                                  Rome, Italy
                             *E-mail: ankurjainankur@sify.com


Mg hydride has a high reversible storage capacity, which amounts to 7.6 wt%
theoretically. It is therefore a promising candidate for hydrogen storage applications.
However, its major drawback is its high desorption temperature of well over 300oC,
which is related to the high stability of the Mg–H bonds and expressed in the high
enthalpy of hydride formation. To make composite of Mg with other hydrogen storage
compounds is an effective method to improve the hydrogen storage properties of Mg so
keeping this fact in mind we prepared Mg-x wt% ZrCrMn composites by high energy ball
milling under argon atmosphere. Structural and hydriding / dehydriding properties of the
Mg–x wt% ZrCrMn composites are investigated by XRD, SEM and PCT measurements.
The amount of hydrogen desorbed at lower temperatures (<300oC) was found to be
increased with the increasing fraction of ZrCrMn. The thermodynamic parameters are
also calculated for different composites. Different reasons have to be considered to
explain the increase in hydrogen desorption amount at relatively lower temperature.

Keywords: Hydrogen           storage;    Magnesium;      ball   milling;    X-ray     diffraction;
microstructures.
                                          M – 22




         Transmission IR Studies of Sodium Borohydride Dehydrogenation

                       Panchatapa Jash and Michael Trenary
    Department of Chemistry, University of Illinois at Chicago, 845 W Taylor Street,
                                Chicago, IL 60607
                       Submitting author: mtrenary@uic.edu


Metal borohydrides of the general formula M(BH4)x are attractive materials for hydrogen
storage applications. In order to realize the potential of these compounds for hydrogen
storage, more information is needed on the temperature-dependent hydrogen-loss
mechanism. We have constructed an apparatus that permits infrared spectra to be
obtained under dynamic vacuum as a function of temperature for hydrogen storage
materials. Small amounts of the borohydride salt is mixed with potassium bromide and
the mixture is pressed into a high transparency tungsten grid. The tungsten grid is in
good thermal contact with a liquid nitrogen cooled reservoir for cooling the sample to
low temperature. By passing current through the grid, the sample can be heated to high
temperatures. The sample temperature is reliably measured with a thermocouple spot
welded to the tungsten grid. In this way, transmission IR spectra can be obtained on
hydrogen storage materials over a wide range of temperatures. The capabilities of this
method are demonstrated with spectra obtained on NaBH4 at room temperature and after
heating to a series of temperatures to just below the melting point. This compound yields
strong IR absorption peaks at room temperature in the B-H stretch region at 2222, 2291,
and 2387 cm-1 and in the BH4 deformation region at 1126 cm-1. Heating the sample to
120, 206, and 303 º C has negligible effect on the spectra indicating that the structure and
composition of the NaBH4 is largely unchanged. However, after heating to 390 ºC, strong
changes appear in the spectra including the appearance of new peaks at 1237, 1264, and
1467 cm-1. These changes are presumably due to a combination of structural
transformations and formation of intermediates that accompany the loss of hydrogen
from the sample.
                                         M – 23




   Metal-Organic Frameworks: Structural, Energetic, Electronic and Mechanical
                                 Properties

        Agnieszka Kuc, Andrey Enyashin, Jan-Ole Joswig, and Gotthard Seifert
    Physical Chemistry, Technical University Dresden, Bergstr. 66b, 01062 Dresden,
                                       Germany
                    E-mail: jan-ole.joswig@chemie.tu-dresden.de


     Metal-organic frameworks (MOFs) recently have appeared as an important class of
porous materials with a low density and a high surface area. These make them ideal
candidates for gas storage and separation, e.g., for H2, N2, CH4.
     By linking together organic and inorganic molecular building blocks a large number
of flexible materials can be obtained (Fig. 1). The optimization of these materials with
respect to, e.g., hydrogen storage capacities needs also an optimization of the 3D
nanopore network. Thus, systematic theoretical investigations of these materials may be
very helpful in designing synthetic pathways.
     In this study we present results from density-functional based tight-binding
calculations of periodic MOF crystals. The investigated systems consist of a cubic array
of Zn4O(CO2)6 building blocks which are connected by different types of organic linkers
(polycyclic aromatic hydrocarbons, carbon cages, etc.). We systematically have studied
the MOF structures and their stabilities as well as their electronic properties.
     The calculated MOF structures agree well with the available experimental structures
and were found to be very stable considering the energies of formation. Several
hypothetical structures have been investigated as well. These systems were found to be
flexible exhibiting decreasing bulk moduli with increasing the length of the organic linker
(0.5–24 GPa). Moreover, our results show that all compounds have band gaps in the
range of 0.5–4 eV, and the states near the Fermi level are dominated by the carbon 2p
states of the organic parts.




                    Fig. 1: A hypothetical metal-organic framework.
                                          M – 24




              Organometallic Complexes as Hydrogen Storage Compounds

                         Anil K. Kandalam1, B. Kiran2, and Puru Jena1
    1
        Physics Department, Virginia Commonwealth University, Richmond, VA 23284
        2
          Department of Chemistry, McNeese State University, Lake Charles, LA 70609
                                 Email: akkandalam@vcu.edu


     The rising population and standard of living around the world combined with limited
supply of fossil fuels and their adverse effect on the environment have made it necessary
to look for alternate clean energy sources. Hydrogen is considered to be an ideal energy
resource if the problems associated with its production and storage can be overcome. For
application of hydrogen in the transportation sector of the economy, the key problem is
its storage. Thus, developing potential hydrogen storage systems with large gravimetric
and volumetric density has become a topic of great current interest.
      Recent studies have demonstrated that atomic clusters not only provide a wealth of
fundamental understanding of the basic interaction between hydrogen and materials but
also how this can be manipulated for the synthesis of ideal hydrogen storage materials.
Of particular importance is the trapping of hydrogen in nearly molecular form with
binding energies intermediate between physisorption and chemisorption. We will focus
on our recent work on the interaction of molecular hydrogen with organo-metallic
clusters and their assemblies. We will address the nature of interaction of hydrogen with
organic molecules and how they can be modified when they are functionalized with
transition metal atoms. Extensive theoretical results based on density functional theory
and optimized geometries of organic molecules (C5H5, C2H4, and C3B2H5) functionalized
with transition metals atoms such as Ti and the mode of hydrogen bonding (associative
versus dissociative) will be presented. The feasibility of using these organo-metallic
clusters as building blocks of bulk hydrogen storage materials are studied by examining
their stability, electronic structure, and ability to store hydrogen with the same density as
in the isolated clusters.


    This work is supported by US Department of Energy (DOE)
                                         M – 25




        Hydrogen Release from Ammonia Borane on Mesoporous Scaffolds

            Abhi Karkamkar, Ashley Stowe, Wendy Shaw and Tom Autrey
       Fundamental Science Directorate, Chemical and Material Science Division,
             Pacific Northwest National Laboratory, Richland, WA 99354
                          E-mail: abhi.karkamkar@pnl.gov


Chemical hydrogen storage materials that release H2 by thermolysis without generating
CO2 offer an attractive option. The ammonia borane is an attractive compound containing
more than 18 wt% hydrogen. However, the kinetics of hydrogen release in not favorable
in bulk materials where H2 is released at 114 oC. We recently reported use of SBA-15 as
scaffold material to form a nanophase ammonia borane species which liberated H2 at
significantly lower temperatures. Here we report the use of MCM-41 and other
mesoporous materials as a scaffold material and investigate the effects on the kinetics of
H2 release. The materials will be carried extensively by 11B NMR, DSC, TGA-MS and
PCT measurements. We further intend to demonstrate the effect of surface modification
and loading capacity of ammonia borane in the scaffold materials on the kinetics and
thermodynamics of H2 evolution.



                                   NH3BH3


                                  Add saturated
                                   solution of
                                   NH3BH3 to
                                   mesoporous
                                    substrate
                                         M – 26




  Structural Characterization of Sodium Borohydrides: Theory and Experiments

     Eunja Kim1, Ravhi Kumar1, Andrew Cornelius1, Malcolm Nicol1, Sven Vogel2,
        Jianzhong Zhang2, Monika Hartl2, Ashley C. Stowe3, Luke Daemen2, and
                                     Yusheng Zhao2
  1
    Department of Physics and Astronomy, and High Pressure Science and Engineering
                        Center, University of Nevada, Las Vegas,
            2
              Los Alamos Neutron Science Center (LANSCE), Los Alamos,
                     3
                       Savannah River National Laboratory, Aiken.
                                 kimej@physics.unlv.edu


Structural changes in sodium borohydride have been observed under pressure in x-ray
diffraction [Kumar et al., Appl. Phys. Lett. 87, 261916 (2005).] and Raman scattering
[Araujo et al., Phys. Rev. B 72, 054125 (2005).] experiments. We report here the results
of theoretical analyses to characterize the crystalline structures observed experimentally.
Density-functional theory calculations were performed for sodium borohydride and
directly compared to the x-ray diffraction and neutron scattering experiments. Our calcu-
lations confirm that the cubic phase is stable up to 5 GPa and an orthorhombic phase
appears above 9 GPa, as observed in x-ray diffraction experiments. Both density-
functional calculations and x-ray diffraction measurements identify a tetragonal
intermediate phase occurring at pressures between 5 and 9 GPa. Neutron diffraction
experiments have been performed for the first time on NaBD4 at high pressures and
confirm the existence of the tetragonal phase. Our density-functional calculations
characterize the space group of the high pressure orthorhombic phase as Pnma. The
calculated equation of state also indicates that the orthorhombic phase is stable up to 30
GPa, which agrees well with experiment.

          This work is supported in part by the U.S. Department of Energy (DOE) under
Award Number DE-FG36-05GO85028 and Cooperative Agreement Number DE-FC52-
06NA27684. This work has benefited from the use of the Lujan Neutron Scattering
Center at LANSCE, which is funded by the DOEs Office of Basic Energy Sciences. Los
Alamos National Laboratory is operated by Los Alamos National Security LLC and DOE
contract DE-AC52-06NA25396. Portions of this work are done at HPCAT (Sector 16 of
the Advanced Photon Source, Argonne National Laboratory). HPCAT is supported by
DOE-BES, DOE-NNSA, NSF, and the W.M. Keck Foundation. The APS is supported by
DOE-BES, under Contract No. W-31-109-ENG-38.
                                         M – 27




      High Density H2 storage on Nanoengineered Scaffolds of Carbon Nanotubes

Carter Kittrell, A. D. Leonard, S. Chakraborty, H. Fan, W. E. Billups, R. H. Hauge, H. K.
                            Schmidt, M. Pasquali, J. M. Tour,
            Department of Chemistry, Rice University, Houston, Texas, 77005
                                 E-mail: kittrell@rice.edu


     An ideal media for hydrogen storage by physisorption should inherently be a multi-
functional material, which addresses at least six major criteria: gravimetric and
volumetric capacity, kinetics, heat transfer, energy efficiency, and reversibility [1]. A
fibrous nanoengineered framework of carbon nanotubes could have well-controlled pore
sizes so that there is little wasted volume of oversized pores, and super-packing of H2
provide high density uptake. The linear structure minimizes tortuosity compared to
granular media, and no activation barrier for adsorption is ideal for the fastest kinetics
and maximum energy efficiency. Physisorption of 1 kg/min of hydrogen at room
temperature (RT) will liberate ca. 250 kW, and single wall carbon nanotubes (SWNTs)
are unsurpassed in thermal conductivity. This scaffold accommodates metal atoms or
nanoparticles, which are predicted to bind H2 at RT, and provides a heat sink for each. A
rigid nanoscale structure will not distort with total H2 removal, for unlimited cycling.
     We have recently suggested such a nanoengineered material, constructed from
carbon nanotubes that are spun as aligned fibrous media [2]. The fiber is expanded and
bonded with cross-linkers which determine the tube-tube spacing. As the DoE 2015
target volumetric capacity exceeds the density of liquid hydrogen, it is not possible to
meet this criterion unless the uptake of the pore is enhanced. Surrounding the H2 with sp2
electron clouds yields a highly favorable equilibrium constant that packs the pore, as
theoretically predicted for graphene [3]. We will show experimental confirmation for
this prediction of super-packed hydrogen pores whereby a number of our 3D
nanoengineered scaffold samples have been tested [4] and we have consistently fit these
data to a ~2x steeper slope for Chahine’s rule whereby the H2 uptake per unit area is
essentially double that of amorphous carbon adsorbents. Progress on alkali metal
functionalization of CNT for hydrogen uptake will also be presented. This work is
supported by DoE DE-FC36-05GO15073 in partnership with the NREL Hydrogen
Storage Center of Excellence.


[1]   From a presentation by M. Dresselhaus, UCSB H2 Symposium (8/28/06)
[2]   Ericson, Lars M., et al., Science, 2004, 305, 1447-1450
[3]   S. Patchkovskii, G. Seifert, et al., PNAS 2005;102;10439-10444 (2005)
[4]   H2 uptake measurement: National Renewable Energy Laboratory, Golden, CO
                                                                       M – 28




                                      Novel Hydrogen Storage System with Ammonia
                        a
                            Yoshitsugu Kojima , bSatoshi Hino, bKyoichi Tange, aTakayuki Ichikawa
                              a
                                Institute for Advanced Materials Research, Hiroshima University
                                    1-3-1, Kagamiyama, Higashi-Hiroshima 739-8530 Japan
                               b
                                 Department of Quantum Matter, ADSM, Hiroshima University,
                                               Higashi-Hiroshima 739-8530 Japan
                                               E-mail: kojimay@hiroshima-u.ac.jp


     Ammonia NH3 has a high hydrogen H2 storage capacity of 18 mass% and a similar
standard enthalpy change (heat of formation) of -31 kJ/molH2 compared with hydrogen-
absorbing alloy (Ti-Cr-V: -34kJ/molH2, LaNi5: -31kJ/molH2). However, the high H2
decomposition temperature (1073 K) due to slow reaction kinetics (high activation
energy) limits the practical application of NH3 as a hydrogen storage material.
     In this study, lithium hydride LiH was mechanically milled in the NH3 atmosphere of
0.9 MPa for 24 h at room temperature. H2 was desorbed from LiH exothermic reaction
( H:-40 kJ/molH2). X-ray diffraction and thermogravimetry indicated that LiNH2 was
formed by the reaction of NH3 and LiH (Fig.1). After H2 desorption, H2 was absorbed in
LiNH2 at 573 K to form LiH and NH3 under the high pressure H2 flow of 0.5 MPa, while
LiNH2 could not absorb H2 in a closed vessel at the pressure and the temperature due to
the low equilibrium NH3 pressure. Thus, we found that the H2 absorption and desorption
of the LiH-NH3 system takes the following reaction path.

             LiH + NH3 ↔ LiNH2 + H2                              (1)

H2 of 8.1 mass% [H2/LiH+NH3] can be reversibly stored in this reaction. The High
pressure H2 flow accelerated the H2 absorption reaction. The Formation enthalpy of H2
absorption was endothermic (positive) and different from the conventional hydrogen
storage materials. It can be understood that the Gibbs free energy difference was
changed from positive to negative with the pressure of H2 flow.

                                   Ball-milled LiH in NH3
                                   at room temperature
Intensity /a.u.




                                                                  Fig.1. Ball-milled LiH in NH3 together with
                                                                  the data of LiH (JCPDS file No. 09-0189) and
                  LiNH2                                           LiNH2 (JCPDS file No. 06-0418).
                  LiH


            15              25    35    45       55         65
                                  θ
                                 2θ /degree
                                        M – 29




Structural Changes in RbBH4 under Pressure Investigated by Synchrotron Powder
                    X-ray Diffraction and Theoretical Studies

                  Ravhi S. Kumar, Eunja Kim and Andrew Cornelius
                  HiPSEC and Department of Physics and Astronomy
                 University of Nevada Las Vegas, Nevada 89154 USA
                           E-mail: ravhi@physics.unlv.edu


     The crystal structure of RbBH4 a potential hydrogen storage compound has been
investigated by high pressure x-ray diffraction up to 26 GPa using angle dispersive x-ray
diffraction technique with a diamond anvil high pressure cell at sector 16, HPCAT,
Advanced Photon Source. Analysis of the high pressure x-ray diffraction data shows
pressure induced structural changes at 2.9 GPa from cubic Fm-3m phase to an
orthorhombic Pnma and a second transition around 8 GPa from the orthorhombic (Pnma)
to monoclinic (P2/c) phase. Our experimental results show a different phase transition
sequence for this material even though the ambient crystal structure is similar to NaBH4
which exhibits cubic --- tetragonal --- orthorhombic transitions under pressure [1].
Detailed experimental results and density functional theoretical (DFT) calculations will
be presented.
     This work is supported in part by the U.S. Department of Energy (DOE) under
Award Number DE-FG36-05GO85028 and Cooperative Agreement Number DEFC52-
06NA27684. HPCAT is supported by DOE-BES, DOE-NNSA, NSF, and the W.M. Keck
Foundation. The APS is supported by DOE-BES, under Contract No. W-31-109-ENG-
38.


[1]. Ravhi S. Kumar etal., App.Phys.Lett. 87, 261916 (2005)
                                         M – 30




  A Molecular Dynamics Study of Hydrogen Adsorption and Diffusion in Zeolites

                       Zeynep Kurban1,*, Neal Skipper1, Steve Bennington2
    1
        Department of Physics & Astronomy, University College London, Gower Street,
                                    London WC1E 6BT, UK
        2
          ISIS Facility, Rutherford Appleton Laboratory, Didcot, Oxon OX11 0QX, UK
                   *Contributing Author; e-mail address: z.kurban@ucl.ac.uk


Microporous crystalline solids such as zeolites have recently attracted attention as
potential hydrogen storage materials. Understanding how molecular hydrogen interacts
with these materials and the material characteristics that influence the adsorption
mechanism are of particular importance in the rational development of hydrogen storage
materials. In this work we report a molecular dynamics study of the diffusion of
molecular hydrogen in zeolites NaX, CaX, MgX and ZSM5; allowing full flexibility of
the host framework, in the temperature range 100-300K. From the simulations the self-
diffusion coefficient of hydrogen is determined as a function of temperature and loading.
The average diffusivity of hydrogen in the zeolites studied is found to decrease in the
order of NaX > ZSM5 > MgX > CaX. The diffusivity of hydrogen in NaX was found to
increase with loading, in agreement with experimental data [1], suggesting that there is
no “gas-like” diffusion and that the molecules are interacting with the Na+ ions. The
adsorption energy per hydrogen molecule at 100 K is found to decrease in the order of
MgX > ZSM5 > CaX > NaX, which is in reverse order of charge to radius ratio (e/r) and
hence the polarising power of the extra-framework cations. These results suggest that the
polarisability of the cations, which is thought to enhance the interaction of hydrogen
molecules with the zeolite surface [2,3], is not the dominating factor determining the
hydrogen adsorption characteristics of zeolite-X and that other factors play a more
important role.


[1] H. Jobic, J. Kärger, and M. Bée, Physical Review Letters, 82, No.21 (1999)
[2] G. Turnes Palomino, M. R. Llop Carayol and C. Otero Areán, J. Mater. Chem., 16,
(2006) 2884-2885
[3] Andrew Yu. Khadokov, Leonid M. Kustov, Vladimir B. Kazansky and Carol
Williams, J. Chem Soc. Fraday Trans., 88 (1992) 3251-3253
                                        M – 31




 Synthesis, Characterization, And Permeation Properties of LaxSr1-xCo1-yMnyO3-
Oxygen Separation Membranes for Use in the Sulfur-Iodide Thermochemical Cycle
                            for Hydrogen Production

          Andrea Ambrosini, Fred Gelbard, Terry Garino, and Tina M. Nenoff
               Sandia National Laboratories, Albuquerque, NM 87185
                           E-mail: aambros@sandia.gov


     Efficient and environmentally sound methods of producing hydrogen are of great
importance as the world explores the use of hydrogen as a clean fuel. Currently studies
are in progress to investigate the use of high temperature thermochemical cycles, driven
by nuclear and/or solar energy, for H2 production. The use of such cycles would reduce
the demand on hydrocarbons which are currently used to produce hydrogen. One
promising candidate for thermochemical hydrogen production is the Sulfur-Iodine (S-I)
cycle, in which the decomposition of H2SO4 into O2, SO2, and H2O at 850°C is a
necessary step. In-situ removal of O2 from this reaction pushes the equilibrium towards
dissociation, thereby increasing the overall efficiency. Any potential membrane for the
separation of oxygen in this step must withstand the high temperatures and corrosive
conditions inherent in this process.
        Perovskites (formula unit ABO3) and perovskite-related structures are promising
materials for such membranes due to their stability at high temperatures, mixed
ionic/electronic conductivities, and ability to stabilize relatively large oxygen
nonstoichiometries. To this end, ceramics based on the double-substituted perovskites
were investigated, in particular the family LaxSr1-xCo1-yMnyO3- (LSCM). LSCM powders
were synthesized by solid state methods and characterized using powder X-ray
diffraction and thermogravimetric analysis. Thermogravimetric analysis data imply that
the materials can reversibly adsorb and desorb oxygen versus temperature and partial
oxygen pressure, an indication of oxygen separation potential, while maintaining the
perovskite structure.
        Circular, 12 mm-diameter self-supported membranes of LSCM were synthesized
by isostatic pressing and sintering of the powders. The resulting pellets were
characterized by X-ray diffraction, four-probe conductivity, and scanning electron
microscopy. Four probe measurements indicate that the materials are mixed ionic-
electronic conductors. Oxygen permeation measurements were performed at temperatures
between 800 – 950 ºC. These results, plus preliminary stability tests under H2SO4
decomposition conditions will be discussed.

Sandia is a multiprogram laboratory operated by Sandia Corporation, a Lockheed Martin
Company, for the US DOE’s NNSA, contract DE-AC04-94-Al85000.
                                         M – 32




Hydrogen Production by Reforming of Natural Gas via Water Splitting Using Dense
                            Ceramic Membranes

          U. (Balu) Balachandran, T. H. Lee, L. Chen, J. J. Picciolo, and S. E. Dorris
         Energy Systems Division, Argonne National Laboratory, Argonne, IL 60439
                                E-mail: balu@anl.gov


Our research is focused on developing dense ceramic membranes that will enable the
efficient and cost-effective production of hydrogen by reforming natural gas (NG) using
oxygen that is formed by water splitting and transported by the membrane. In our
approach, hydrogen is produced on the steam side of the membrane while synthesis gas is
produced on the NG side. Steam dissociates into oxygen and hydrogen at high
temperatures; however, due to small equilibrium constant, only very small concentrations
of hydrogen and oxygen are generated, even at very high temperatures. Significant
amounts of hydrogen or oxygen can be generated at moderate temperatures, however, if
the equilibrium is shifted toward dissociation by using a mixed-conducting membrane to
remove either oxygen or hydrogen.
As a first step to demonstrate our concept, we have studied hydrogen production via
water splitting at moderate temperatures (500- 900°C) with novel mixed-conducting
membranes. We have measured a maximum hydrogen production rate,
  11 cm3(STP)/min-cm2, with a 0.25-mm-thick membrane at 900°C using 50 vol.% water
vapor on one side of the membrane and 80% hydrogen (balance helium) on the other
side. In these experiments, hydrogen was used only as a model gas to establish a high
oxygen potential gradient. The pure oxygen that is generated can be used to reform NG.
To demonstrate this concept, we used methane on one side and steam on the other side of
the membrane. With methane as the feed gas, hydrogen was produced on both sides of
the membrane. The oxygen produced by water dissociation was transported across the
membrane and reacted with methane to form synthesis gas. The synthesis gas can be
subjected to a water-gas shift reaction to produce more hydrogen and a stream enriched in
CO2 for sequestration.


Work supported by U.S. Department of Energy (DOE), Energy Efficiency and
Renewable Energy, Office of Hydrogen, Fuel Cells, and Infrastructure Technologies
Program and Office of Fossil Energy, National Energy Technology Laboratory’s
Hydrogen and Syngas Technology Program, under Contract DE-AC02-06CH11357.
                                          M – 33




  Direct Production of Pressurized Hydrogen from Waste Aluminum without Gas
                                   Compressor

                  T. Hirakia, N. Okinakaa, H. Uesugib and T. Akiyamaa
 a
   Center for Advanced Research of Energy Conversion Materials, Hokkaido University,
                   Kita 13 Nishi 8, Kita-ku, Sapporo 060-8628, Japan
 b
   Waseda University, Wasedatsurumaki-cho 513, Shinjuku-ku, Tokyo 162-0041, Japan


An innovative environment-friendly hydrolysis process for generating high-pressure
hydrogen with recycling waste Al has been proposed and experimentally validated [1].
The effect of the concentration of NaOH solution on H2 generation rate was mainly
examined. In the experiments, distilled water and Al powder were placed in the pressure-
resistance reactor made of Hastelloy, and was compressed to a desired constant water
pressure using a liquid pump. The NaOH solution was supplied by liquid pump with
different concentrations (from 1.0 to 5.0 mol/dm3) at a constant flow rate into the reactor
by replacing the distilled water and the rate of H2 generated was measured
simultaneously. The liquid temperature in the reactor increased due to the exothermic
reaction given by Al + OH– + 3H2O = 1.5H2 + Al(OH)4– + 415.6 kJ. Therefore, a high-
pressure H2 was generated at room temperature by mixing waste Al and NaOH solution.
As the H2 compressor used in this process consumes less energy than the conventional
one, the generation of H2 having a pressure of almost 30 MPa was experimentally
validated together with Al(OH)3—a useful by-product. The exergy losses in the proposed
system (150.9 MJ) is 55% less than that in the conventional system (337.7 MJ) in which
the gas compressor and production of Al(OH)3 consume significantly more energy.


[1] T. Hiraki, et. al., Environ. Sci. Technol., 41, 4454-4457, 2007
                                        M – 34




 A Cu/Pt Near-Surface Alloy for Water-Gas Shift Catalysis Studied by STM, XPS,
                                TPD, and DFT

      Ronnie T. Vang, Jan Knudsen, Joachim Schnadt, and Flemming Besenbacher
     Interdisciplinary Nanoscience Center (iNANO) and Department of Physics and
                       Astronomy, University of Aarhus, Denmark.
                                 E-mail: rtv@inano.dk

     Hydrogen produced from steam reforming of fossil fuels accounts for the majority of
the present hydrogen consumption and is expected to play a key role for the short term
introduction of a hydrogen-based economy. The water-gas shift (WGS) reaction, in
which carbon monoxide (CO) and water (H2O) react to form carbon dioxide (CO2) and
hydrogen (H2), is a crucial step in the production of clean (CO free) hydrogen, and as
such it is important to optimize the WGS process to achieve an overall effective hydrogen
production. In particular, efficient WGS catalysis is needed for onboard reforming of,
e.g., methanol in vehicles powered by low temperature fuel cells. Clean hydrogen (CO
free) is needed to run the low temperature fuel cells, and at the same time the weight of
the fueling system, including the WGS reactor, should be as low as possible to preserve
fuel efficiency.
     In this study we use a combination of scanning tunneling microscopy (STM), x-ray
photoelectron spectroscopy (XPS), temperature programmed desorption (TPD), and
density functional theory (DFT) to study a bimetallic Cu/Pt model catalyst for the WGS
reaction.1 From STM, XPS, and DFT we find that when Cu is evaporated onto Pt(111) at
high temperature (800 K) a thermodynamically stable surface alloy is formed. The
topmost atomic layer in this surface alloy consists purely of Pt, and the Cu atoms are
embedded in the subsurface layer with the highest Cu concentration in the first
subsurface layer. The TPD measurements show that the subsurface Cu atoms weaken the
binding of CO to the topmost Pt layer, thus minimizing the risk of CO poisoning of the
catalyst. This observation is confirmed by the DFT calculations. Furthermore, the
calculations show that the Cu/Pt(111) surface alloy effectively activates water, which is
the rate limiting step in the WGS reaction on several metal surfaces, while at the same
binding the reaction products (CO) and reaction intermediates (formate) weakly, whereby
poisoning of the catalyst surface is reduced. The results thus show that the bimetallic
Cu/Pt catalyst is a promising candidate for an improved WGS catalyst.


1.     J. Knudsen, A. U. Nilekar, R. T. Vang, J. Schnadt, E. L. Kunkes, J. A. Dumesic,
       M. Mavrikakis and F. Besenbacher, J. Am. Chem. Soc., 2007, 129, 6485-6490.
                                         M – 35




     Soft X-ray and Electron Spectroscopy Studies of Oxide Semiconductors for
                    Photoelectrochemical Hydrogen Production

                 Lothar Weinhardt, Marcus Bär, and Clemens Heske
 Department of Chemistry, University of Nevada Las Vegas, Box 4003, 4505 Maryland
                       Parkway, Las Vegas, NV 89154-4003
                    Submitting author: heske@unlv.nevada.edu


     For an efficient photoelectrochemical (PEC) water splitting device, the
photoelectrode material needs to fulfill several primary requirements. For example, the
band gap needs to be optimized to allow maximum absorption of the solar spectrum,
while simultaneously reaching a sufficiently high voltage for electrolysis. Furthermore,
the conduction and valence band edges need to have optimized electronic positions in
order to minimize or eliminate the need for a bias voltage. Finally, the material needs to
be stable in an electrolyte environment with either very high or very low pH value.

      It is the purpose of the presentation to demonstrate how a spectroscopic “tool chest”
that includes UV- and X-ray photoelectron spectroscopy, inverse photoemission, and
synchrotron-based high-brilliance soft X-ray absorption and emission spectroscopy can
aid in the development of suitable electrode materials. In particular, they can shed light
on the electronic surface properties such as surface band gap and band edge positions.
Furthermore, they can probe chemical and electronic alterations induced by electrolytes
and photon excitation. And, finally, they lend themselves to in-situ spectroscopic
investigations at the liquid-solid interface. Using selected metal oxide films as examples,
first experimental steps will be presented and discussed in view of their potential to help
in the development of efficient and stable photoelectrode materials for solar hydrogen
production.
                                           M – 36




         Contamination of Complex Metal Hydrides with O2, H2O, and CO2

             Daniel E. Dedrick, Rich Behrens, Jr., Robert W. Bradshaw, and
                                 Christopher D. Moen
                     Sandia National Laboratories, Livermore, CA,
                             E-mail: dededri@sandia.gov


     Safe and efficient hydrogen storage is a significant challenge inhibiting the use of
hydrogen as a primary energy carrier. Although energy storage performance properties
are critical to the success of solid-state hydrogen storage systems, operator and user
safety is of highest importance when designing and implementing consumer products. As
researchers are now integrating high energy density solid materials into hydrogen storage
systems, quantification of the hazards associated with the operation and handling of these
materials becomes imperative. The experimental effort presented in this paper focuses on
identifying the hazards associated with producing, storing, and handling sodium alanates,
and thus allowing for the development and implementation of hazard mitigation
procedures. The chemical changes of sodium alanates associated with exposure to oxygen
and water vapor have been characterized by thermal decomposition analysis using
simultaneous thermogravimetric modulated beam mass spectrometry (STMBMS) and X-
ray diffraction methods. Partial oxidation of sodium alanates, an alkali metal complex
hydride, results in destabilization of the remaining hydrogen-containing material. At
temperatures below 70°C, reaction of sodium alanate with water generates potentially
combustible mixtures of H2 and O2. In addition to identifying the reaction hazards
associated with the oxidation of alkali-metal containing complex hydrides, potential
treatment methods are identified that chemically stabilize the oxidized material and
reduce the hazard associated with handling the contaminated metal hydrides.
                                            M – 37




          Preliminary Performance Assessment of Commercially-Available
                               Hydrogen Sensors

                       Nathan D. Marsh and Thomas G. Cleary
        Fire Research Division, National Institute of Standards and Technology,
                           Gaithersburg, MD 20899, USA
                           E-Mail: nathan.marsh@nist.gov


     The hydrogen economy envisions wide application of energy delivery solutions
based on hydrogen fuel cells or combustion systems. The public’s acceptance of these
new energy delivery systems will rely to some extent on the perceived and actual safe
application of the technologies. To this end, reliable detection of an accidental hydrogen
gas release and mitigation of the hazard through designed safety systems is a key
component of hydrogen powered systems in commercial, residential, and transportation
uses. In anticipation of this emerging market, inexpensive hydrogen gas sensors based on
a range of sensing technologies are becoming increasingly available. There is a need to
characterize sensors in conditions relevant to their end-use application.
     As part of an effort to develop standard test methods for the performance of these
sensors, we employed the Fire Emulator/Detector Evaluator, an instrumented flow system
designed to study the response of fire detectors (smoke, heat, gas), in a preliminary study
to evaluate the performance of a representative selection of commercially-available
hydrogen sensors. These sensors depend on a variety of sensing technologies including
metal-oxide semiconductors, electrochemical cells, catalytic bead pellistors, thermal
conductivity sensors, and sensors employing a combination of technologies. They were
evaluated both for their response to hydrogen concentrations up to half the lower
flammability limit, as well as their response to nuisance gases (CO, CO2, NOx,
hydrocarbon gas and vapor—all potentially present in hydrogen dispensing and storage
areas) as well as dynamic changes in environmental conditions by varying temperature,
humidity, and flow velocity. These performance evaluations provide guidance for the
development of a test method designed to assess real-world performance of hydrogen gas
sensors. The ultimate goal is to develop standard test methods to be employed by product
certification agencies.
                                           M – 38




 Hydrogen behavior and coloration of tungsten oxide films prepared by magnetron
                     sputtering and pulsed laser deposition

           S. Nagata1), A. Inouye2), S. Yamamoto2), B. Tsuchiya1), T. Shikama1)
     1)
        Institute for Materials Research, Tohoku University, Sendai 980-8577, Japan
                 2)
                   Japan Atomic Energy Agency, Takasaki 370-1292, Japan
                                  nagata@imr.tohoku.ac.jp


     Hydrogen fuel is considered to be a clean energy resource for the future. Because
the hydrogen gas has a relatively low explosive limit in the atmosphere, development of a
sensor of hydrogen gas is very important to handle hydrogen safely. Tungsten tri-oxide
films covered with a thin catalyst layer is one of the candidates for hydrogen sensing
devices that show a reversible coloration phenomenon under hydrogen exposure.
Meanwhile, the mechanism of the gasochromic phenomenon is not fully understood. In
the present study, the relation between the hydrogen and gasochromic property was
investigated by measuring simultaneously hydrogen concentration depth profiles and
optical absorption in tungsten oxide films.
     The tungsten oxide layer with thickness of 100-400 nm was prepared on C, Si and
SiO2 substrates at a temperature between 300 and 600 K by RF magnetron sputtering
with a pure metal W target in a mixture of argon and oxygen gas, and by pulsed laser
deposition with WO3 target. The structure and morphology of the films were examined
by X-ray diffraction and scanning electron microscope. The hydrogen concentration in
the film was determined by ion beam analysis techniques. The colorating and bleaching
effects were observed in amorphous and oriented crystalline films with relatively large
amount of hydrogen; the excellent gasochromic properties were found in the HxWO3
films with value of x about 0.8, while poorer coloration was observed in the films with
less hydrogen. Under hydrogen exposure, the hydrogen concentration in the film
increased with increasing the optical absorption in the wavelengths of 600 – 1000 nm.
                                             M – 39




            Review of Codes and Standards For Hydrogen Refueling Stations

                  Shantanu Mahajana, Donald Edwardsa, Dr. John Shewchunb
      a
          Graduate student, Alternative Energy Technology, Wayne State University,
                                  Detroit, MI 48202, USA
           b
               Adjunct Professor, Wayne State University, Detroit, MI 48202, USA
                                    shewchun@wayne.edu



Hydrogen has been promoted as an energy carrier to replace fossil fuels such as oil in
transportation systems. It is claimed to be a very clean form of energy. Fuel cell
technology for utilizing hydrogen is still in an embryonic stage and most of the future
development of the so-called Hydrogen Economy will depend on a suitable hydrogen
refueling infrastructure. The lack of suitable, properly agreed upon Codes and Standards
is a major barrier for such infrastructural development. This paper focuses on procedures
and precautions that need to be standardized so that safe, user-friendly operations will
emerge. We use examples of existing refueling stations to argue our case.
                                           M – 40




             High Power TeraHertz Source for Studies of Hydrogen in Materials#

                 G. Myneni1,2, A. Hutton2, G. Kraaft2, and B.S. Shivaram1*
     1
         Department of Physics, University of Virginia, Charlottesville, Virginia 22901
                       2
                        Jefferson Lab, Newport News, Virginia 23606
                                *E-mail: bss2d@virginia.edu


Recent progress in the development of Superconducting Radio Frequency (SRF)
accelerating cavities has enabled reliable support, without field emission, of continuous
wave (CW) accelerating gradients of order 10 MV/m and higher. This development
means that, CW accelerators with beam energies of several tens of MeV are possible
from accelerators of roughly the size of a large room. We will present preliminary design
considerations of such a device as a driver for a compact Tera-Hertz source. Such a
source is capable of delivering THz in the 10 Watt range thus opening up a wide range of
studies of hydrogen in materials.

#Supported by Jefferson Science Associates, LLC under U.S. DOE Contract No. DE-
AC05-06OR23177
                                          M - 41




   A New Solar Thermochemical Water Splitting Cycle for Hydrogen Production

                     Ali T-Raissi, Cunping Huang, Nazim Muradov
      University of Central Florida, Florida Solar Energy Center, Cocoa, FL 32922
                                Email : ali@fsec.ucf.edu


Hydrogen production via water splitting using solar energy is the “Holy Grail” of the
hydrogen economy. At the Florida Solar Energy Center (FSEC), we have developed a
hybrid photo/thermo-chemical water splitting cycle that employs the quantum portion of
the solar spectrum for the production of hydrogen and the thermal energy (i.e. IR) portion
of solar radiation for generating oxygen. FSEC’s sulfur-ammonia (S-NH3) hybrid
photo/thermochemical water splitting cycle is represented by the following reactions:

SO2(g) + 2NH3(g) + H2O(l) (NH4)2SO3(aq)              (chemical absorption, 300 K) (1)
(NH4)2SO3(aq) + H2O (NH4)2 SO4(aq) + H2(g)           (solar photocatalytic, 350 K) (2)
(NH4)2SO4(aq) 2NH3(g) + H2SO4 (l)                    (solar thermocatalytic, 525 K) (3)
H2SO4(l) SO2(g) + H2O(g) + 1/2O2(g)                  (solar thermocatalytic, 1125 K) (4)

High temperature decomposition of sulfuric acid step of the sulfur-family TCWSCs
presents serious materials and catalyst deactivation challenges. Platinum based catalysts
are currently the most active ones used for the H2SO4 decomposition, but they lose their
activity very rapidly. To overcome this difficulty, metal sulfate sub-cycles have been
developed. Here, we describe a new family of solar thermochemical water splitting
cycles based on the modified version of S-NH3 cycle that includes a metal oxide/metal
sulfate sub-cycle as follows:

SO2(g) + 2NH3(g) + H2O(l) (NH4)2SO3(aq)               (chemical absorption, 300 K) (5)
(NH4)2SO3(aq) + H2O (NH4)2 SO4(aq) + H2(g)            (solar photocatalytic, 350 K ) (6)
x(NH4)2SO4 + M2Ox 2xNH3 + M2(SO4)x + xH2O             (solar thermocatalytic, 673 K) (7)
M2(SO4)x(s) xSO2(g) + 2MO(s) + (x-1)O2(g)             (solar thermocatalytic, 1373 K) (8)


Where, M = Zn, Mg, Ca, Ba, Fe, Co, Ni, Mn, Cu.

Kinetic data obtained for the reactions 6-8 from a series of light and dark experiments
using a thermogravimetric/differential thermal analyses/mass spectrometer (TG/DTA/
MS) and the zinc oxide/zinc sulfate sub-cycle will be presented and discussed.
                                                           M – 42




                          Crystal Structure of Unsolvated Ca[BD4]2 Phases

             F. Buchter1, D. Sheptyakov2, Z. Łodziana1, A. Remhof1, and A. Züttel1
 1
     EMPA Materials Sciences and Technology, Überlandstrasse 129, CH-8600 Dübendorf,
                             Switzerland. florian.buchter@empa.ch
      2
        Laboratory for Neutron Scattering, ETH Zurich & Paul Scherrer Institute, CH-5232
                                   Villigen PSI, Switzerland.


     Ca[BH4]2 with a high gravimetric hydrogen density of 11.5 mass% is among the
most promising hydrides for hydrogen storage. Ca[BH4]2 decomposes at 320°C. It was
recently reported that the use of MgB2 instead of B as starting material can significantly
reduce the kinetic barriers for the formation of Ca[BH4]2, increasing the interest for this
compound [1]. The crystal structure of Ca[BH4]2 is to a large extent still unknown, with a
variety of structures found depending on the synthesis process and temperature of the
samples. A room temperature crystal structure of Ca[BH4]2 obtained by drying a
commercially available complex Ca[BH4]2 2THF was recently determined and called -
phase [2]. In sample synthesized from MgB2 by solid gas mechanochemical reaction [1],
the room temperature -phase of Ca[BH4]2 phase was found to transform to a unsolved -
phase of Ca[BH4]2 at about 130°C [1]. In sample synthesized by wet chemical method
[3], coexistence of a unsolved -phase with the -phase from room temperature up to
330ºC [4]. We have investigated and solved the crystal structure of the -phase of
Ca[BD4]2 by combined X-Ray and neutron diffraction on a sample synthesized from
MgB2 by mechanochemical reaction [5]. Investigation of the structural model parameters
of eight space group candidates, combined with a detailed ab-initio calculation of the
formation and vibrational energy, have shown the structural model with space group
P42/m (# 84) to be the best candidate combining the lowest energy and highest symmetry
[5]. in the diffraction pattern of this sample we observed small peaks coming from small
amount of -phase at both temperature were the main part of the sample is in the -phase
(< 130ºC) or in the -phase (> 130ºC). A structural model of the -phase was introduced
in the fit of the diffraction pattern. A preliminary investigation and solution of the crystal
structure of the -phase of Ca[BD4]2 by combined X-Ray and neutron diffraction on a
sample synthesized from the wet chemical method was done. A first structural candidate
with orthorombic space group Pca21 (# 29) has been found [5]. Ab-initio calculation has
shown this model to be stable with similar energy compared to the the -phase,
explaining the coexistence of -phase and -phase in the range 20ºC to 290ºC.
[1] G. Barkhordarian et al., accepted in Journal of Physical Chemistry.
[2] K. Miwa, M. Aoki, T. Noritake, N. Ohba, Y. Nakamori, S. Towata, A. Züttel, Phys. Rev. B 74, 155122 (2006).
[3] K. Chlopek, C. Frommen, A. Lèon, O. Zabara and M. Fichtner, J. Mat. Chem., 17, 3496-3503 (2007).
[4] M. D. Riktor et al. In preparation
[5] F. Buchter et al. In preparation
     ABSTRACTS OF
  CONTRIBUTED PAPERS




   POSTER SESSION – II

WEDNESDAY, NOVEMBER 14

     8:00 – 10:00 PM
                                          W–1




                        Low Temperature Solid Oxide Fuel Cell

Beycan Ibrahimo lu 1, Mahmut D. Mat2, Rafig Alibeyli3, Yuksel Kaplan2, Sadig Kuliyev3
                         1-Gazi University/Ankara/Turkey
                            2-Ni de University/Turkey
               3-Vestel Defense Industry R&D group/Ankara/Turkey
                         E-mail: rafig.alibeyli@yahoo.com

 SOFCs in different power ranges have been developed which are constructed from
yttrium stabilized zirconium (YSZ) membranes having activities in high temperatures
(750-1000 oC). Some of them were tested and are being used nowadays. YSZ SOFCs are
very expensive for their high temperature applications. One of the reasons is that, it is
very difficult to choose the current collector materials with electronic conductivity and
having the same temperature expansion coefficient as YSZ membrane. For this reason, it
is important to develop low temperature SOFC (600 - 650 0C) with high performances. It
is possible to use some stainless steel types as current collectors in these systems and the
membranes need to have high ionic conductivity at low temperatures. In the presented
work, for planar SOFC systems, a special technology has been developed for the
production of membranes on the base of cerium and gadolinium oxides and the surfaces
of membranes were covered with anodic and cathode catalysts forming the membrane
electrode group (MEG).The performance tests for MEG were conducted for single,
double, ternary and quarter cell stacks. Membranes were designed circular shape with
active surface diameter 55 and 85 mm. The current collectors were designed by different
shape of heliozoan flow channels from stainless steels. The thickness of current collector
plates were 7 -12 mm. Experiments were conducted in the temperature range 450-680 oC
and atmospheric pressure. Pure hydrogen or hydrogen produced by direct catalytic
decomposition of natural gas and LPG was used as fuel. For the achievement of working
condition of membranes heating rate was t0                 = 100C /min. The electrical
characteristics of produced membranes were tested in different H2 molar relations:
n(H2) n(Air). Membrane tests were conducted in direct introduction of the hydrogen and
air to the stack or the gases were introduced each cells separately by parallel channels. In
order to establish stable active state of membranes, operating time should be about 45-60
minutes in each temperature stages. For the most active membranes, the open circuit
voltage values were between 0,8-0,9 V. These potential values were at V(H2)/V(air) =1:5,
at 650 oC. It has been observed that, at constant temperatures and in definite gas velocity
ratios for different MEGs, on the base of U/I- curves, that maximum activity were650oC.
                                          W–2




         Alternative Materials to Pd Membranes for Hydrogen Purification

                           Thad Adams and Paul S. Korinko
                          Savannah River National Laboratory,
                              Thad.Adams@srnl.doe.gov


The cost effective production of high purity hydrogen is required to move hydrogen fuel
cell technology from limited application to more widely accepted use. Current hydrogen
purification routes commonly use high value precious metals for purification. For
instance, hydrogen is often purified using palladium-silver membranes in systems
referred to as diffusers. These diffusers are often expensive and may be variable
reliability. Consequently, alternative materials for the Pd-Ag membranes are of interest.

To address this niche market, SRNL has been developing a “common metallic alloy” for
use as a replacement membrane material for hydrogen diffusers. The alloys of interest
contain nickel, vanadium, and titanium. Like the Pd alloys they are susceptible to
hydriding under certain temperature conditions and experience brittle fracture if cooled in
the presence of hydrogen. This presentation will describe the attributes of the alloys that
have been tested and will show relative permeation rates using both electrochemical cell
measurement and gas permeation techniques.

WSRC-STI-2007-00379
Prepared for the U.S. Department of Energy under Contract DE-AC09-96SR185
                                          W–3




  Understanding Channel Connectivity and Catalyst Loading in PEM Fuel Cells:
  Nanoscale Current Imaging Using Conducting AFM and Electrodeposition of Pt
                    Particles Using a Nafion® as a Template

Steven K. Buratto, Asanga D. Ranasinghe, David A. Bussian, James R. O’Dea and Horia
                                       Metiu
         Department of Chemistry and Biochemistry, University of California,
                              Santa Barbara, CA 93106


     Nafion® membranes are commonly used as electrolytes in proton exchange
membrane fuel cells (PEMFCs). Under the operating conditions the membrane absorbs
water and phase separates into nanoscale hydrophobic and hydrophilic domains. Proton
transport from the anode to the cathode takes place through the hydrophilic channels.
The overall efficiency of electricity production through these channels is dependent on a
continuous pathway from the anode to the cathode, and the presence of a catalyst particle
at both ends. Our research group has been interested in understanding these two
conditions and we have approached this problem on two fronts: We have developed
techniques to measure the overall efficiency of the aqueous channels in commercial fuel
cells; and we have developed new methods for improving the efficiency of catalyst
loading in fuel cells.
     The electrochemically active area of a PEMFC is investigated using conductive
probe atomic force microscopy (CP-AFM). A platinum coated AFM tip is used as a
nanoscale cathode in an operating PEMFC. We present results that show highly
inhomogeneous distributions of conductive surface domains at several length scales. In
addition, we have developed a new characterization technique, phase current correlation
microscopy (PCCM), which provides a direct measure of the electrochemical activity for
each aqueous domain. Our results show that a large number (~60%) of the aqueous
domains present at the surface of an operating fuel cell membrane are inactive. We
attribute this to a combination of limited aqueous domain connectivity and catalyst
accessibility.
     In order to improve the catalyst accessibility we have developed a procedure to
deposit Pt particles electrochemically on an electrode covered with a Nafion® membrane.
Platinum ions travel through the hydrophilic channels of the membrane and the platinum
deposits are formed at the place where the channels make contact with the planar
electrode. This procedure deposits the catalyst only at the end of the hydrophilic channels
that cross the membrane; no catalyst is placed under the hydrophobic domains. We have
used our electrodeposition method to construct a working fuel cell with nearly a 100-fold
decrease in the platinum catalyst material.
                                           W–4




  A Study on Nafion/ZrO2-TiO2 Composite Membrane for High Temperature and
                           Low Humidity PEMFCs

      Dong Woong Choi, Ki Tae Park, Un Ho Jung, Hyang Mee Lee, Kook Chun,
                             and Sung Hyun Kim*
                       E-mail: apolon7908@hanmail.net


     ZrO2-TiO2 mixed oxides with various Zr:Ti molar ratios were prepared by sol-gel
method. Nafion composite membranes with 1 wt% ZrO2-TiO2 mixed oxides were
                 




fabricated from a recast procedure using Doctor Blade technique. The membranes were
characterized by water uptake, ion exchange capacity (IEC), proton conductivity, x-ray
diffraction (XRD), scanning electron microscopy (SEM) and, thermogravimetric analyzer
(TGA).
        These membranes were tested in a single cell at temperatures of 80    and 120
with various H2/Air humidity conditions. The test results were compared to a commercial
Nafion 112 and a recast Nafion membrane. A nafion/ZrO2-TiO2 composite membrane
                                 




using 3:1 of Zr:Ti molar ratio showed the highest performance, and the maximum power
density of this modified membrane was of 154mW/cm-2(0.461 V) at 80             with R.H.
conditions of 10%. The composite membrane with 1:3 of Zr:Ti molor ratio was better
than any other membrane and, the performance showed 108 mW/cm-2(0.488 V) at 120
with 10% R.H. condition.




Key word : PEMFC, Nafion, ZrO2, TiO2, composite membrane
                                          W–5




New Mesoporous Transition Metal Oxides for the Photocatalytic Splitting of Water

                    Ying Y. Cui, Martin O. Jones, Peter P. Edwards
                 Inorganic Chemistry Laboratory, University of Oxford,
                             South Parks Road, OX1 3QR
                            E-mail: ying.cui@chem.ox.ac.uk


The increasing consumption of fossil fuels has the potential to cause both an energy crisis
and environmental problems. Hydrogen is believed to be one possible option to help
solve these issues. Currently, the major source of hydrogen comes from fossil fuels,
whose production is energy costly, polluting and not sustainable. On the other hand, solar
energy is both abundant and renewable, but rather difficult to store effectively.
Converting solar energy into hydrogen, by using a water splitting photocatalyst to
generate hydrogen is a possible route to a renewable, “carbon-free” future.




                              Photoreaction of water

Currently most of the photocatalysts available are active only under ultraviolet
irradiation, which accounts for about 5% of solar energy. In our work, we are attempting
to develop new methods to prepare visible-light-active catalysts. A series of compounds
based on mesoporous WO3, promoted with different transition metals has been
investigated. It is found that the catalysts and supports synthesized by this route are much
finer, with higher surface areas, than conventional routes. Under green LED irradiation
(representative of visible light) and Xe lamp irradiation, hydrogen and oxygen have been
produced via water splitting.
                                          W–6




 Molecular-Dynamics Simulations of Proton Transport in Liquid Phosphonic Acid
                       and Polyvinyl Phosphonic Acid

                         Jan-Ole Joswig and Gotthard Seifert
    Physical Chemistry, Technical University Dresden, Bergstr. 66b, 01062 Dresden,
                                       Germany
                    E-mail: jan-ole.joswig@chemie.tu-dresden.de


     Polyphosphonic acids are promising candidates for solvent-free proton conductors in
proton-exchange membrane fuel cells. These membranes operate without water as a
solvent and, thus, allow a higher operating temperature. However, the proton conduction
mechanism in these systems is only poorly understood. Atomistic molecular-dynamics
(MD) simulations can considerably contribute to the understanding of the conduction
process and the transport mechanisms.
     Currently, we are focussing on the proton transport in liquid phosphonic acid and in
polyvinyl phosphonic acid – a simple model polymer (Fig. 1). We utilize density-
functional based MD simulations of these model systems to obtain, e.g., the speed of the
proton transfer (hopping rates), pair-distribution functions, and diffusion coefficients in
the liquid. Also the proton transfers along and between polymer chains is investigated.




                   Fig. 1: A model structure of poly-vinyl phosphonic acid.

     In all studies, special attention is paid to the geometrical constraints for proton-
transfer reactions and the role of additional water molecules in both the liquid and the
model polymer structures. This may help in designing new proton-conducting polymers
based on polyphosphonic acids.
                                                 W–7




                    Nanowire-based Catalyst Support for PEM Fuel Cells

                 Madhu S. Saha1, Ruying Li1, and Andy X. Sun1*, Mei Cai2*
 1
     Department of Mechanical and Materials Engineering, University of Western Ontario,
                              London, ON. N6A 5B9, Canada
     2
       General Motors Research and Development Center, Warren, MI 48090-9055, USA
              *corresponding Authors: mei.cai@gm.com and xsun@eng.uwo.ca


        The proton exchange membrane fuel cell (PEMFC) is one of the most promising
power sources for mobile and stationary applications due to its high energy conversion
efficiency, high power density, low operating temperature, and zero emissions. For
vehicle applications, the challenges remain in the development of a durable and ultra-low
noble metal loading electrocatalyst to reduce the system weight, volume, and cost as
compared to internal combustion engine. Materials developed based on the applications
of nanotechnology, such as nanoparticles, nanotubes, and nanowires, are currently being
studied extensively as one of the potential solutions to address the above challenges [1].

        Compare to nanoparticles and nanotubes, nanowires (NWs) are prominent
nanomaterials that exhibit unique material properties. These properties make them
suitable for applications in certain technology areas including nanoelectronics and
nanoelectrodes [2]. Among various classes of NWs being studied, certain metal oxide
NWs have the advantages to be used as catalyst supports for the dispersion of noble metal
nanoparticles in practical applications. Our approach in this work is to grow metal oxide
NWs directly onto carbon fibers of commercially available carbon
paper (Fig.1), followed by deposition of Pt nanoparticles onto the
NWs (insert) as low cost and durable fuel cell electrodes. Fig. 1
shows the typical TEM images of the SnO2 NWs grown directly on                      20 nm

carbon paper and electrodeposition of Pt nanoparticles on one
nanowire.

     In this talk, we will present some of the results obtained with
Pt metal catalysts supported on metal oxide NWs, an alternative
catalyst supports, for PEMFC applications [3].
                                                                            Fig. 1: SEM image of SnO2 NWs grown on
References:                                                                 carbon paper. Inset is TEM image of Pt
1.    H.A. Gasteiger, S.S. Kocha, B. Sompalli, F.T. Wagner, Appl. Catal. B: nanoparticles deposited on a single SnO2 NW.
      Environ., 6 (2005) 9.
2. A.S. Edelstein, R.C. Cammarata, Eds. Nanomaterials: Synthesis, Properties and
   Applications, 1996.
3. M. Saha, R. Li, X. Sun and M. Cai. “High Electrocatalytic Activities of Platinum
   Nanoparticles on SnO2 Nanowire-based Electrodes”. Electrochemical Solid-State
   Lett. (2007), 10 (8), B130-133.
                                         W–8




        Enhancement of Protonic Conductivity in the Near Surface Regions
             of Radiation Induced Polymer Electrolyte Membranes

                      B. Tsuchiya, S. Nagata, K. Saito, T. Shikama
                  Institute for Materials Research, Tohoku University,
                   2-1-1, Katahira, Aoba-ku, Sendai 980-8577, Japan
                            E-mail: tsuchiya@imr.tohoku.ac.jp


New protonic conduction processes of the perfluorosulfonic acid polymer electrolyte
membranes by gamma-ray irradiation at the dose up to 173 kGy and room temperature in
air have been found by direct current (DC) resistance and alternating current (AC)
impedance measurements. The conductivities between the polymer electrolyte and the
electrode, made of platinum, at 300 and 373 K in vacuum were enhanced to be about two
and one, respectively, order magnitude higher than that the unirradiated one. The new and
original activation energies of the conductivities in the temperature range below and
above 343 K were distinguished to be 0.12±0.05 and 0.84±0.03 eV, respectively, which
corresponded to potential energy of hydrogen diffusion due to the radiation induced
defects and the existing sulfonate group. It was also revealed by means of ultraviolet,
visible and infrared optical absorption and hydrogen ion-exchange capacity
measurements that the radiation induced defects such as fluorocarbon and peroxy
radicals, and C=O including in carbonyl groups were related to the new proton
conduction processes. The modification of the hydrogen absorption characteristics due to
the radiation induced defects in the near surface regions induces to the enhancement of
the proton conductivity.
                                         W–9




Degradation of Pt catalysts in polymer electrolyte fuel cells: A new perspective from
                           molecular dynamic simulation

                                   Xiangyang Zhou
                 Department of Mechanical and Aerospace Engineering
                   University of Miami, Coral Gables, Florida 33128
                               Email: xzhou@miami.edu

With steady advancement of polymer electrolyte fuel cell (PEFC) technology and a
feasible technical roadmap toward meeting the stringent performance and cost targets,
catalyst durability during PEFC operation becomes one of the major remaining
challenges to commercialization of the PEFC based power sources. Almost all theories,
hypotheses, and models in literature invoke electrochemical dissolution/re-crystallization
mechanisms to explain the loss of the electrochemical active area (ECA) of the Pt and Pt
based nano-crystalline catalysts with significant discrepancies to experimental
observations. Herein we report our recent findings in molecular dynamic (MD)
simulations of Pt nano-crystals in a polymer electrolyte environment. The MD
simulations reveal that the Pt nano-crystals can undergo instantaneous disintegration
under the interaction between charged Pt nano-crystals and polarized polymer electrolyte.
The simulation results also indicate that the instantaneous disintegration releases high
density heat that could result in further ripening of the catalyst and damages in the
polymer electrolyte.
                                         W – 10




        Nanoporous Biocarbon as High-Capacity Storage Material for Hydrogen

   Jacob Burress1, Mikael Wood1, Sarah Barker1, Jeffrey Pobst1, Raina Cepel1, Galen
  Suppes2, Parag Shah2, Phil Buckley3, Mike Benham4, Michael Roth5, Carlos Wexler1,
                                     Peter Pfeifer1
            1
             Department of Physics, University of Missouri, Columbia, MO, USA.
  2
      Department of Chemical Engineering, University of Missouri, Columbia, MO, USA.
                    3
                      Midwest Research Institute, Kansas City, MO, USA.
                    4
                      Hiden Isochema Ltd., Warrington, United Kingdom.
         5
           Department of Physics, University of Northern Iowa, Cedar Falls, IA, USA.
                                  JacobBurress@mizzou.edu


The Alliance for Collaborative Research in Alternative Fuel Technology (http://all-
craft.missouri.edu) is developing nanoporous biocarbon for vehicular storage of methane
and molecular hydrogen by physisorption. We have optimized carbon made from
corncob for high-capacity methane storage. The best materials for methane storage also
exhibit exceptional capacity for hydrogen storage. We have obtained storage capacities
of 73-91 g H2/kg carbon at 77 K and 47 bar, and 1.0-1.6 g H2/kg carbon at 293 K and 47
bar, validated in three separate laboratories. Excess adsorption and total amount stored
have been measured on gravimetric and volumetric instruments (Sievert apparatus).
Using experimental nanopore volumes, we convert excess adsorption into absolute
adsorption isotherms and obtain experimental binding energies of hydrogen in nanopores.
Pore structure analyses are obtained from small-angle x-ray scattering, scanning electron
microscopy, nitrogen adsorption (subcritical adsorption), and methane adsorption
(supercritical adsorption). Experimental hydrogen storage capacities and binding
energies will be compared with molecular dynamics simulations of hydrogen carried out
in our group on carbon substrates with various geometries.



Research support: NSF (EEC-0438469), University of Missouri, Midwest Research
Institute, U.S. Department of Education (GAANN), U.S. Department of Energy (W-31-
109-Eng-38), U.S. Department of Energy (DE-FG-07ER46411), and U.S. Department of
Defense (NSWC-BAA-N0016407R6967).
                                         W – 11




     Neutron Scattering Approaches to the Chemical and Physical Properties of
                               Ammonia-Borane

 Nancy Hess, Abhi Karkamkar, Venci Parvanov, Greg Schenter, Chris Mundy, Shawn
Kathmann, Ashley Stowe, Monika Hartl, Luke Daemen, Thomas Proffen, Craig Brown,
                 Eugene Mamontov, Mike Hartman, Tom Autrey

  Pacific Northwest National Laboratory, Los Alamos National Laboratory (LANSCE),
                National Institute of Standards and Technology (NCNR)

Ammonia borane NH3BH3 has received a great deal of interest recently as a solid state
hydrogen storage material since it was discovered to release hydrogen under mild thermal
conditions. The unique di-hydrogen bonding interactions between the adjacent protic NH
and hydridic BH groups control the dynamics of hydrogen motion and formation. In
order to understand the fundamental interactions of the hydrogen in ammonia borane,
quasielastic and inelastic neutron scattering techniques have been used to study the
structure, phase transitions, vibrational spectroscopy, and rotational dynamics. The low
frequency region of the neutron vibrational spectrum has been probed to investigate the
nature of dihydrogen bonding in the ammonia borane solid and assignments have been
made based on isotopic labeling and theory. The structural phase transitions have been
explored with powder samples to gain insight into proton disorder in the tetragonal phase.
Further, the proton rotational dynamics have been probed throughout the temperature
range 10-300K to determine the nature of the proton motion as well as the rotational
energy barrier. This work was supported by the Office of Basic Energy Sciences of the
Department of Energy by the Chemical Sciences program. The Pacific Northwest
National Laboratory is operated by Battelle for the US Department of Energy.
                                         W – 12




                Thermodynamics of Doped Complex Metal Hydrides

          J. Karl Johnson1,2, Sudhakar V. Alapati3, Bing Dai1, David S. Sholl2,3
              1
                Department. of Chemical Engineering, University of Pittsburgh,
                                Pittsburgh, PA 15261, USA
                         2
                           National Energy Technology Laboratory
                                    Pittsburgh, PA 15236
           3
             Department. of Chemical Engineering, Carnegie Mellon University,
                                Pittsburgh, PA 15213, USA
                                   E-mail: karlj@pitt.edu


Several complex metal hydrides have been proposed as hydrogen storage materials
because of their high gravimetric and volumetric densities. One of the main problems
with these materials is that they are either too stable, requiring unacceptably high
temperatures to release the hydrogen, or not stable enough, releasing hydrogen at low
temperatures or being difficult to rehydride. The reaction enthalpy of metal hydrides may
be tuned by doping the materials with elements that can form compounds in both the
hydrided and dehydrogenated states. A properly chosen dopant can either decrease the
reaction enthalpy, making the dehydrogenated state more favorable, or increase the
enthalpy, favoring the hydrogenated state. We have used first principles density
functional theory to estimate the free energies of various doped metal hydride systems.
We have evaluated the zero temperature enthalpies, without inclusion of zero point
energies, for 18 different doped systems. Most systems are found to be unstable with
respect to phase separation at 0 K. We have included configurational entropy to estimate
the temperature at which the doped systems become stable. Most doped compounds are
estimated to remain unstable with respect to phase segregation up to temperatures that are
too high to be of practical interest. We have identified one system that is stable with
respect to phase segregation at T > 435 K when phonon density of states are included in
the calculations. We have computed the van’t Hoff plot for Sc7H16Ti + 16 LiBH4
Sc7B16Ti + 16 LiH + 32 H2 and compared this to the undoped reaction. Doping increases
the vapor pressure at a given temperature, but only by a factor of 2 to 4. We have also
computed several different candidate structures for Mg(BH4)2 and have compared the
energies and computed XRD structures to the complex structure recently identified
experimentally. We examine the possibility of doping this material and discuss
limitations of using density functional theory for computing the thermodynamics of
doping of such complex structures.
                                         W – 13




           Synthesis of Hydrides by High-Pressure Ball Milling (HP-BM)

                     I. Llamas-Jansa, C. Rongeat, and O. Gutfleisch
     Institute for Metallic Materials, P.O. Box 270016, D-01171 Dresden, Germany
                          E-mail: i.llamas.jansa@ifw-dresden.de


High-pressure ball milling (HP-BM) is an effective method for the synthesis of novel
light metal hydrides and complex hydrides under reactive atmospheres (up to 150 bar
H2). The combination of HP-BM with an especially designed vial (produced by Evico
Magnetics) allows the in-situ monitoring of the hydrogen pressure and vial temperature
variations taking place during the synthesis process. Thus, information about the
efficiency of the reactions can be obtained before removing the powder from the vial. At
the IFW Dresden, a variety of light metal hydrides (e.g. MgH2), complex hydrides (e.g.
NaAlH4) and Reactive Hydride Composites (RHC; e.g. LiBH4/MgH2) are being
synthesised by changing the initial mixture of reactants and catalyst (e.g. Ni, Ti, TiCl3,
Ti-isopropoxide, and ScCl3), and the HP-BM conditions (e.g. H2 pressure, ball-to-powder
ratio, and milling time). The thermodynamic and kinetic properties of the materials are
analysed by high-pressure differential scanning calorimetry (HP-DSC, at pressures
between 1 and 140 bar H2 in a dynamic mode), intelligent gravimetric analysis (IGA),
and a Siervert’s type apparatus. Additional structural characterisation of the powder is
carried out by X-ray diffraction (XRD) and Raman spectroscopy. The results have shown
the effect of the synthesis conditions on the hydride formation and the thermodynamic
and kinetic properties of the powders. For instance, the use of different catalysts and H2
pressures was found to modify the reaction efficiencies during the synthesis of doped
NaAlH4 from a mixture of NaH + Al + (4% mol) catalyst. In particular, the monitoring
of the reactions during milling showed that TiCl3 and ScCl3 are more efficient catalysts
than Ti, which led to the incomplete transformation of the reactants into NaAlH4. The
reaction was improved by increasing the reactive milling pressure from 50 to 100 bar H2.
Different milling pressures (10, 40 and 90 bar H2) were also found to change the
reactivity of the Mg99Ni1 alloy during the synthesis of MgH2. The reaction was observed
to be incomplete in the case of a 10 bar atmosphere, whereas higher milling pressures led
to the complete transformation of Mg into the hydride. The synthesis of Mg(BH4)2 by
HP-BM of LiBH4 and MgCl2 was proved by Raman spectroscopy.
                                         W – 14




Time-resolved Uptake and Structure of Hydrogen in the Graphite Intercalate KC24

   Arthur Lovell1,*, Steve Bennington2, Neal Skipper1, Ron Smith2, Felix Fernandez-
                                        Alonso2

1. Dept. of Physics and Astronomy, UCL, Gower St., London WC1E 6BT, UK
2. ISIS Facility, Rutherford Appleton Laboratory, Chilton, Didcot OX11 0QX, UK
                   *Contributing author’s email: arthur.lovell@ucl.ac.uk


Graphite intercalation compounds (GICs) show promise as candidate materials for a
hydrogen storage system [1, 2], possessing excellent physisorptive reversibility. Their
study has benefits for understanding the dynamics of sorption and locating hydrogen
intercalation sites, undertaken with a view to designing a new generation of GICs
optimised for storage. The second-stage potassium-GIC KC24 has a known saturation
uptake of 2 H2 per K ion at 77 K [3] but the structure of the hydrogenated compound was
never satisfactorily confirmed. Revisiting this system, we conducted, in conjunction with
neutron spectroscopy studies [4], in situ neutron diffraction experiments on KC24(D2)x for
0 < x < 2, at 50, 20 and 2 K, to provide unprecedented time-resolved structural
information from the GIC as it adsorbed and desorbed deuterium. A self-consistent model
of the c-axis structure of the deuterated compound was obtained with the aid of Rietveld
refinement. This was combined with novel insights into the greater challenge of
modelling the in-plane structure, which is the focus of ongoing work.

[1] Solin, S. A., Zabel, H., Advances in Physics, 37 (1988) 87-254

[2] Deng, W., Xu, X., Goddard, W. A., Phys. Rev. Lett. 92 (2004) 166103

[3] Watanabe, K., Soma, M., Onishi, T., Tamaru, K., Nature, Phys. Sci. 233 (1971) 160

[4] Lovell, A., Bennington, S. M., Skipper, N. T., Gejke, C., Thompson, H., Adams, M.
A., Physica B, 385-386 (2006) 163-165
                                                     W – 15




       Synthesis and Structural Investigation of Li3Na(NH2)4 and LiNa2(NH2)3.

 Rebecca L. Lowton,a William I . F. David,a,b Martin O. Jones a, Simon R. Johnsona and
                                  Peter. P. Edwardsa
            a Inorganic Chemistry Laboratory, University of Oxford, b ISIS Facility, Rutherford Appleton
                                                 Laboratory, UK
                                     E-mail: rebecca.lowton@chem.ox.ac.uk

The synthesis and characterization of new hydrogen-containing compounds is a rapidly
growing area of research. We present here two new phases formed from the reactions of
LiNH2 with NaNH2.
       Synchrotron X-Ray powder diffraction patterns of the products formed show the
presence of varying proportions of two new mixed metal amide phases, identified as
Li3Na(NH2)4 and LiNa2(NH2)3, (see figure). Li3Na(NH2)4 was found to be a considerably
non-stoichiometric material whereas LiNa2(NH2)3 was only formed as a single line phase.
These differences are discussed in terms of the differing crystal structures of these phases
and the ionic mobility (or lack thereof) of the metal ions within these structures.

       Li      Na      N     H




   a                                 b                                 c
 Figure: Crystal structures of a) LiNH2, b) Li3Na(NH2)4 and c) LiNa2(NH2)3. Note the structural
 similarities between the LiNH2 and Li3Na(NH2)4 structures.
                                           W – 16




 Influence of Heat Transfer Mechanisms on the Performance of Complex Hydride
                                    Tanks

    Gustavo Lozano, Nico Eigen, Claude Keller, Martin Dornheim, Rüdiger Bormann
               Institute for Materials Research, GKSS Research Centre,
                             D-21502 Geesthacht, Germany
                        E-mail address: gustavo.lozano@gkss.de


     Achieving a successful integration of complex hydrides into a hydrogen storage
system e.g. for a fuel cell car, requires to understand the influence of heat transfer
mechanisms on charging and discharging kinetics. In complex hydrides low temperatures
as well as high temperatures close to the thermodynamic equilibrium lead to slow
kinetics, resulting in small temperature window of operation. Therefore, heat
management presents a high challenge and requires a detailed understanding of the
materials behavior under realistic conditions.

     In this work, the effect of the powder bed size on reaction kinetics of NaAlH4
catalyzed with TiCl4 is studied experimentally for the first time. For this purpose, titration
measurements were performed using different cell diameters. The temperature was
measured during the process at different positions inside the bed of material, providing
detailed information about the influence of heat conduction. Experimental results show
that under the applied conditions up to a critical size larger diameters can lead to faster
kinetics for the first and second absorption reactions. However, at larger cell diameters
temperatures up to 200°C were measured during the first absorption step in the sample
bed. This leads to a drastic delay in the start of the second one, reducing the overall rate
of the process. The reasons for the unexpected behavior are discussed and measures for
optimization are proposed.
                                                        W – 17




                   Development of Metal Hydrides for High-Pressure MH Tank

                 T. Matsunaga*, T. Shinozawa, K. Washio, D. Mori, M. Ishikiriyama
           Higashifuji Technical Center, Toyota Motor Corporation, 1200, Mishuku, Susono,
                                    Shizuoka, 410-1193, JAPAN
                            *E-mail: tomoya@matsunaga.tec.toyota.co.jp


          Hydrogen storage method is one of the most important issues to introduce fuel cell
     vehicles. Although compressed hydrogen gas tank is convenient in charge and discharge
     process of hydrogen, its volumetric storage density is limited to less than 20kg/m3 and it
     is not sufficient. High pressure metal hydride(MH) tank (Fig.1) can holds more than
     twice the amount of hydrogen as compared to the same volume of 35MPa compressed
     hydrogen gas tank. This system has a potential to be used as conveniently as a
     compressed hydrogen gas tank.
          The merit of the high pressure MH tank system is improved by the use of a metal
     hydride with high desorption pressure. In this study, TiCrV and TiCrVMo alloy with
     BCC structure has been developed for this system and it shows 2.5 mass% of effective
     hydrogen capacity (Fig.2). Generally, the plateau pressure of metal hydrides increases
     with the decrease of the lattice size. This was also observed for TiCrV ternary alloy.
     However, for TiCrVMo alloy, the desorption pressure is sensitive not only to the lattice
     size but also to the content of Mo, and it turned out that Mo has the special effect to
     increase the desorption pressure of the hydride. Besides the results as a material,
     hydrogen charging/discharging properties as a high pressure MH tank with the developed
     materials will be also presented.

                                                                        100
                                                                                  298 K
Aluminum fin of hot exchanger CFRP Aluminum liner
                                                           Pressure [MPa]




      H2                                      Coolant                         1

                                                                                                        TiCrVMo
        Valve                                                               0.1
                                                                                                        TiCrV
                  MH            tubes      Sealing
                  powder                                                                                TiCrMn
                                                                    0.01
                                                                        0.0                1.0        2.0         3.0
      Fig 1.Schematic view of high-pressure MH                                            hydrogen [mass%]
                         tank
                                                                 Fig 2.PC isotherms of the developed MHs
                                       W – 18




 Toward the Direct Synthesis of Alane: Hydrogenation Studies of Aluminum in
                         Supercritical Fluid Media

                      G. Sean McGrady and Terry Humphries,
     University of New Brunswick, Fredericton, NB, Canada; smcgrady@unb.ca;
                         Craig M. Jensen and Reyna Ayabe,
                       University of Hawaii, Manoa, HI, USA.




Alane, (AlH3)x has a hydrogen content of 10 wt%, fast H2 release kinetics at modest
temperatures, and good kinetic stability. However, its marginal thermodynamic stability
has thwarted its direct preparation from Al and H2 (Eq. 1), except under conditions of
extreme temperature and pressure [1]. The remarkably high solubility of hydrogen gas
in supercritical fluids (SCFs) prompted us to explore H2/SCF mixtures as media for the
hydrogenation of alminum. Initial studies using supercritical CO2 and Al metal resulted
in partial hydrogenation, giving around 0.5 wt% H2 [2]. We are currently exploring the
utility of alternative SCF media and mixtures with donor solvent capability, along with
the use of hydrogen transfer catalysts, with the aim of stabilizing the ephemeral
molecular AlH3 intermediate, followed by removal of the donor and transformation to
the polymeric binary hydride (Eq. 2).



     Al (s) + 1.5 H2 (g)       (AlH3 )x (s)                             Eq. 1

                           L
     Al (s) + 1.5 H2 (g)       L·AlH3 (s)          (AlH3 )x (s)         Eq. 2
                                              –L



 1. S. K. Konovalov and B. M. Bulychev, Inorg. Chem. 1995, 34, 172.
 2. T. Humphries, G. S. McGrady, R. Ayabe and C. M. Jensen, APS Annual Meeting,
    Denver, CO, 2007; GRC on Hydrogen-Metal Systems, Waterville, ME, 2007.
                                          W – 19




  H-induced Structural Changes in Metal Membranes for Hydrogen Purification:
                   Model Predictions vs Neutron Diffraction

      Diana E. Nanu(1), Amarante J. Böttger(1), Wim G. Haije(2), Jaap F. Vente(2), Bas B.
                                 van Aken(2), Matt G. Tucker(3)
(1)
     Dept. Materials Science & Engineering, Delft University of Technology, Mekelweg 2,
                               2628 CD Delft, The Netherlands,
                                      d.e.nanu@tudelft.nl
   (2)
        Energy research Centre of the Netherlands, Westerduinweg 3, 1755 LE Petten, The
                                          Netherlands
  (3)
       ISIS Facility, Rutherford Appleton Laboratory, Chilton, Didcot, OX11 0QX, United
                                           Kingdom


     A technical challenge associated with the production of high-purity hydrogen is the
development of highly selective membranes that can withstand elevated temperatures and
pressures in gas atmosphere. Dense metal membranes are most suitable for this purpose.
Nevertheless, the lifetime of existing metalmembranes in thermal cycles from operational
conditions to room temperature is quite short, as often failure occurs due to deformation
and fracture caused by the large specific volume change during the hydride formation and
decomposition. The design of suitable membrane materials requires knowledge of the
stability of phases and structural changes that occur during H absorption/desorption. This
can be achieved by combining statistical thermodynamics, computational methods, and
experimental structural analysis.
     Recently, we have developed a computational method that describes the possible
structural changes during H absorption/desorption in noble metal alloys. The method
takes into account the possible ordering of H atoms and/or the correlations between the
atomic positions in the metal lattice and the occupation of interstitial sites with H atoms.
The method is based on the cluster variation method (CVM) and allows to predict the
phase stability as function of composition and temperature. Thus, multicomponent alloys
with specific phases and structures suitable for predetermined process conditions can be
designed.
     This paper presents our latest model and experimental results on the stability of
phases and the H-induced structural changes in Pd-alloys. Alloy systems expected to
have various order-disorder transitions on both metal and interstitial sublattices were
chosen for this purpose. Neutron diffraction measurements were performed to determine
the H (D)-site occupancies and the correlations with the occupancies of the metal atoms.
Rietveld refinement and Reverse Monte Carlo methods were used for the analysis of
long- and short-range order, respectively. The atomic configurations determined from
experimental information are discussed in comparison with those assessed by our CVM
approach and by first principles calculations.
                                          W – 20




                 The Synthesis and Crystal Structure of LiK(BH4)2

   E. Anne. Nickels a, Martin Owen Jones a, William I. F. Davida,b , Simon R. Johnson a,
                Rebecca L. Lowtona, M. Sommarivab and Peter P. Edwards a
a
  Inorganic Chemistry Laboratory, University of Oxford, South Parks Road, Oxford, UK
                                       OX1 3QR,
b
  ISIS Facility, Rutherford Appleton Laboratory, Chilton, Didcot, Oxon., UK OX11 0QX
                              Anne.Nickels@chem.ox.ac.uk


     Borohydrides are considered an important hydrogen storage material because they
are light weight materials that contain a large amount of hydrogen. Lithium borohydride
for example, contains 18.5 wt% hydrogen.
     Here we report the synthesis and characterization by synchrotron X-ray diffraction
and intelligent gravimetric analysis of the first mixed alkali metal borohydride,
LiK(BH4)2.




Figure 1. A schematic diagram of (a) the proposed LiK(BH4)2 structure and
(b) orthorhombic LiBH4
                                          W – 21




         Electron Microscopy Study of MgH2 Powder for Hydrogen Storage

    Biswajit Paik, Allan Walton, David Book, Vicky Mann, I. P. Jones, I. R. Harris
 Department of Metallurgy and Materials Science, School of Engineering, University of
                        Birmingham, Edgbaston, UK, B15 2TT.
                                 bxp202@bham.ac.uk



Magnesium Hydride (MgH2) acts as an important base material for a number of Mg
based hydrogen storage material. We here report electron microscopy study of MgH2
powder in relation to improve the hydrogen storage kinetics. The report includes the
study of microstructure, crystal structure and the electronic structure of MgH2.
Microstructure study in the ball milled MgH2 powder has been viewed in terms of the
evolution of grain and particle size and their distributions under the high energy ball
milling (up to 60 hours) and hydrogen cycles (up to 6 cycles). The images of grains
before and after ball milling enable us to estimate the decrease in the grain size with
milling. These results are compared with the XRD measurements. Kikuchi diffraction
pattern has been found sensitive to the lattice strain introduced into the powder hydride
materials by ball milling. With H-cycling, this strain disappears and grain growth takes
place. The average grain size before and after the first cycle indicates: smaller the grain
before cycling, larger is the growth after the cycling. In order to determine the hydrogen
sorption mechanism in terms of the crystallography, we have made several attempts
where MgH2 is transformed into Mg under the influence of the beam electron of the
TEM. Determination of the orientation relation between the structures of MgH2 and
magnesium under the phase transformation MgH2 Mg has been the prime interest in the
study of the crystal structure using electron diffraction. This orientation relation has been
used to propose a scheme to describe possible movements of the Mg atoms under the
hydrogen sorption mechanism. Electron Energy-Loss Spectroscopy has been used to
estimate the plasmon energy and the band gap energy of MgH2 using the dielectric
function derived from the low-loss spectrum obtained from the EELS.
                                          W – 22




     Correlated Rotational Motions of Ammonia Borane in Orthorhombic Molecular
                                       Crystal

  Vencislav Parvanov1, Gregory Schenter1, Donald Camaioni1, Nancy Hess1, Thomas
Proffen2, Luke Daemen2, Monika Hartl2, Wendy Shaw1, Herman Cho1 and Tom Autrey1
 1
     Fundamental Science Division, Pacific Northwest National Laboratory, Richland WA;
      2
        Manuel Lujan, Jr. Neutron Scattering Center, Los Alamos National Laboratory, Los
                                          Alamos NM
                             E-mail: vencislav.parvanov@pnl.gov


     Ammonia borane is a solid powder and shows structure with NH---HB dihydrogen
bonds forming a network near perpendicular to the BN dative bond. Because of this
specific molecular arrangement, early studies suggested rotational dynamic behavior for
such molecular crystals. Later experimental studies considered independent rotations of
ammonia and borane parts of the molecule in the crystal. Measured activation energies
for these motions in orthorhombic phase (bellow 225K) show much higher barrier for
BH3 rotation of 21-25 kJ/mol than NH3 rotation of 8-13 kJ/mol [1]. Recent theoretical
models [2] suggest intra molecular rotations as initial step of the first dehydrogenation
stage of ammonia borane. Thus description and explanation of the rotational behavior and
barriers is vital for further development of strategy for use of this material as hydrogen
carrier.
     We will present the structure of ammonia borane at 175K from Neutron Diffraction
measurements and Pair Distribution refinement technique, as well as results for rotational
activation energies from fitting of Quasi-Elastic Neutron Scattering and 2H NMR data.
These energies agree with previously published barriers and confirm the higher barrier of
BH3 compared to NH3 rotation. We also used electronic structure methods to simulate the
rotations and calculate the barriers in cluster model build from the refined structure at
175K. These calculations clearly show the different barriers for ammonia and borane
rotations about the BN bond. Furthermore, the model reveals correlation in these motions
and suggests that the barrier measured for BH3 does not represent independent rotation.
We will conclude with an explanation of the difference in barrier heights based on energy
decomposition analysis of the intermolecular interactions at barrier geometries of BH3
and NH3 rotations.


[1] Penner et al. Inorg. Chem. 1999, 38, 2868
[2] Nguyen et al. J. Phys. Chem. A 2007, 111, 679
                                          W – 23




     Reaction Mechanisms of Formation of NaBH4+MgH2 by Hydrogenation of
                                 NaH+MgB2

  Claudio Pistidda, Gagik Barkhordarian, Torben Jensen, Matthias Podeyn, Christopher
           Nwakwuo, Thomas Klassen, Martin Dornheim, Rüdiger Bormann
                           E-mail: Claudio.Pistidda@gkss.de


     The recent discovery of the unique kinetic property of MgB2 [1, 2, 3, 4] in facilitating
the hydrogenation of light metal complex borohydrides at moderate conditions has
created new prospects to develop high capacity low enthalpy hydrogen storage materials.
These new composite materials which consist of a binary light metal hydride (like LiH,
NaH and CaH2) and MgB2 can be hydrogenated at much more moderate conditions
compared to the usual route of hydrogenating the mixture of the corresponding binary
hydride and pure Boron [1, 2]. This suggests that MgB2 is kinetically superior to pure
Boron in these reactions, however the corresponding mechanisms are not yet understood.
With the aim of clarifying the mechanisms through which MgB2 functions, we
investigated the hydrogenation of NaH+MgB2 by in-situ Synchrotron X-ray diffraction,
high pressure DSC and high pressure titration. The results indicate that contrary to what
was expected, formation of NaBH4 does not occur directly, but follows the formation of
MgNaH3. Further experimental results will be presented to discuss the role of NaMgH3 in
these reactions.


[1] G. Barkhordarian, T. Klassen, R. Bormann, International patent pending, publication
number: WO 2006/063627 A1
[2] G. Barkhordarian, T. Klassen, R. Bormann, accepted by J. Alloys Comp., 440 (2007),
L18.
[3] J. J. Vajo, S. L. Skeith, F. Mertens, J. Phys. Chem. B; 109 (2005), 3719.
[4] J. J. Vajo, F. O. Mertenz, S. L. Skeith, M. P. Balogh, International patent pending,
International publication number WO 2005/097671.
                                        W – 24




               Hydrogen in nano-metals: clusters, wires and thin films

 Astrid Pundt, Mohammed Suleiman, Kai Nörthemann, Diana Marcano, Eugen Nikitin,
  Stefan Wagner, Ryota Gemma, Helmut Uchida, Felix Schlenkrich, Stefan Schneider

    Universität Göttingen, Institut für Materialphysik, Friedrich Hund Platz 1, 37077
                                   Göttingen, Germany

     Nano-sized M-H systems offer several properties that differ from bulk. Main
advantage is the fast kinetic that results from the large surface faction. But also the
thermodynamics is modified [1]: First, by new surface related sorption sites coming into
play and changing the over-all solubility of the metal. They affect the phase boundaries
of the nano-M-H system. Second, by stabilizer effects, both electronical and mechanical
in nature, which modify the physical properties. This is especially visible in the two
phase region where sloped plateaus are reported for M-H clusters and thin films.
Additionally, new structures occur that strongly influence the hydrogen uptake behaviour
of the M-H system. In this paper, different perspectives on M-H nano-metals will be
discussed pointing out the knowledge of the nano-system lattice structure as a basic
necessity.

[1] Pundt A., Kirchheim R., Hydrogen in metals: microstructural aspects, Annual Review
Materials Research 36 (2006) 555-608.
                                         W – 25




 Inelastic Neutron Scattering in the study of molecular hydrogen storage materials

                                 AJ Ramirez-Cuesta
  ISIS Facility, STFC, Rutherford Appleton Laboratory, OX11 0QX United Kingdom


INTRODUCTION
Inelastic Neutron Scattering (INS) spectroscopy is an ideal tool to study hydrogen
containing materials, since the incoherent scattering cross section of hydrogen is almost
20 times larger than any other element [1]. It is also very easy to establish comparison
between experimental data and theoretical calculations, allowing a straightforward
comparison and interpretation of the data when DFT calculations are available [2]. The
rotational spectra of molecular hydrogen, does also fall within the range of the TOSCA
spectrometer at ISIS. Therefore, it can also be used to study adsorption of molecular
hydrogen in porous materials [1,3].

EXPERIMENTAL
The TOSCA spectrometer, at the ISIS Facility, is an indirect geometry INS machine. It
measures the scattering function along a well defined trajectory, which has been
optimized to study hydrogen containing materials. The resulting spectra look like an IR
spectra. The resolution of TOSCA is 1.5% ∆E/E and the range is from 32 to 8000 cm-1.
The spectra are collected at 13K in order to minimize thermal effects.

THE ROTATIONAL DYNAMICS OF MOLECULAR HYDROGEN IN
CONFINEMENT
The rotational energy levels of the hydrogen molecule, in solid hydrogen (when
exhibiting very weak interactions), are given by:
E JM = J ( J + 1)B
where J and M are the angular quantum numbers. For hydrogen, the value of B is
7.35 meV. INS spectroscopy can measure the sharp para → ortho hydrogen transition, in
particular the J 1←0 transition, that corresponds to an energy transfer of 2B. The value of
the constant B is determined by the moment of inertia of the hydrogen molecule. When
the hydrogen molecule interacts with a surface the energy spectrum is more complex, and
the nature of the spectrum will depend on the intensity and, in particular, characteristics
of the interaction with the surface.
     The results show that the interaction of molecular hydrogen with carbons is very low
and gives rise to a small shift of the rotational levels. On the other hand zeolites, MOFs
and aluminophosphates show very large interactions between the hydrogen molecule and
the substrate. See figure 1. The rotational dynamics of molecular hydrogen in clathrates
will also be presented and discussed.
                                0     4      8        12           16   20   24
                                                 Energy Loss/meV



Figure 1. Top, spectrum of solid hydrogen (no interactions); bottom hydrogen on CoALPO (strong
interaction)

 REFERENCES
 1.- PCH Mitchell, SF Parker, AJ Ramirez-Cuesta and J Tomkinson in “Vibrational
 Spectroscopy with Neutrons” World Scientific, London, (2005).
 2.- A J Ramirez-Cuesta, Comp Phys Commun 157 226-238 (2004).
 3.- A J Ramirez-Cuesta, P C H Mitchell, S F Parker, P A Barrett Chem Commun 1257
 (2000)

  *E-mail: a.j.ramirez-cuesta@rl.ac.uk
                                         W – 26




          Reversible Hydrogen Storage in Catalyzed Calcium Borohydride

                           Ewa Rönnebro, Eric Majzoub,
     Sandia National Laboratories, 7011 East Avenue, Livermore, CA 94551 USA.
                            E-mail: ecronne@sandia.gov


Hydrogen storage is a key technology for realizing the hydrogen economy. It is a grand
challenge to find new materials for onboard hydrogen storage that meets the performance
targets of USA’s DOE i.e. 6wt% hydrogen, 1.5kWh/liter, 2.0kWh/kg and 1000 cycles.
However, with a future perspective, the solid state H-storage materials are more likely to
be selected as appropriate candidates. We will here present recent results on synthesis and
characterization of calcium borohydride. At Sandia, we are using solid-state routes
including ball milling and high-H2 pressure sintering in autoclaves. In order to get clues
to better understand the hydrogen diffusion process, we are using X-ray diffraction
techniques to determine the crystal structures by the Rietveld method. We have recently
shown that by using a theoretically predicted enthalpy favored reaction, i.e. CaB6 +2CaH2
+ 10H2         3Ca(BH4)2, we can partially re-hydride calcium borohydride from its
decomposition products at 700 bar and 400ºC. We have thoroughly characterized this
product and also a sample of more high-purity made by removing the solvent from an
Ca(BH4)2(THF)2 (Aldrich). According to synchrotron in-situ data from ESRF and
Brookhaven, the desorption reaction mechanism is more complex than anticipated. It
crystallizes in an orthorhombic space group, F2dd, slightly different than proposed by
Miwa et al (PRB, 2006) and also appears in at least two other structural forms, depending
on temperature and preparation methods. We are continuing exploring the intriguing
reaction mechanism and its potential for application as a 9.6wt% reversible hydrogen
storage material.
                                         W – 27




    An Overview of the Structural, Energetic and Thermodynamic Properties of
              Li-Mg-N-H Systems from Density-functional Theory

         C. Moysés Araújo1, Ralph H. Scheicher1, Puru Jena2, and Rajeev Ahuja1,3
1
  Condensed Matter Theory Group, Department of Physics, Uppsala University, Box 530,
                                S-751 21 Uppsala, Sweden.
     2
       Department of Physics, Virginia Commonwealth University, Richmond, Virginia
                                       23284, USA.
   3
     Applied Materials Physics Group, Department of Materials and Engineering, Royal
              Institute of Technology (KTH), S-100 44 Stockholm, Sweden.
                                moyses.araujo@fysik.uu.se


An ideal hydrogen storage material should possess high capacity, and absorb and release
hydrogen at ambient operating conditions. A very promising prospective approach
towards the achievement of these goals considers the storage of hydrogen in Li-Mg-N-H
systems. However, a clear understanding of the structural and physical properties of
intermediate phases that form during destabilization reactions in these materials is still
lacking. By means of density functional theory calculations and ab initio molecular
dynamics simulations, we provide a detailed analysis [1] of the ground-state structure of
the novel hydrogen absorber Li2Mg(NH)2. We found the N-H bonds to be slightly
stronger in Li2Mg(NH)2 than in Li2NH, which can be understood from the electrostatic
interaction between hydrogen and cationic sub-lattices. Despite this, the hydrogen release
from the Li2Mg(NH)2–LiH mixture is found to display more favorable thermodynamics
than that from the Li2NH–LiH mixture. This counterintuitive result has its root cause in
the formation of a magnesium nitride phase. Furthermore, we have evaluated the free
energies (at 0 K) of all possible compounds that are formed as hydrogen is released from
xLiH–yMg(NH)2 mixtures. We will present a detailed analysis of the thermodynamics of
the reactions involving the composition ratios (x=2, y=1), (x=8, y=3) and (x=12, y=3),
with emphasis on the effect of the different intermediate steps.


[1] C. Moysés Araújo, Ralph H. Scheicher, Puru Jena, and Rajeev Ahuja, “On the
structural and energetic properties of the hydrogen absorber Li2Mg(NH)2”, Applied
Physics Letters (in press).
                                        W – 28




         Molecular Simulation of Structural Changes of Ammonia Borane

 Gregory K Schenter, Chris Mundy, Shawn M Kathmann, Vencislav Parvanov, Nancy J
             Hess, Wendy J Shaw, Herman M Cho and Thomas Autrey,
            Pacific Northwest National Laboratory, Richland, WA 99352
                           E-mail: greg.schenter@pnl.gov


We will report studies of the structural changes of Ammonia Borane as a function of
temperature using molecular simulation techniques, relating them to neutron diffraction
and NMR measurements. A series of molecular simulations were performed at
temperatures of 15, 120, 175, 220, 230, 240, 250, 275, and 330K, spanning the structural
phase transition from an orthorhombic to a tetragonal phase at 225K. It is believed that
this transition is related to the rotational dynamics of the NH3 and BH3 moieties, and a
better understanding of the details these motions will provide insight into the hydrogen
release mechanism for this class of materials. Calculations were performed combining
Density Functional Theory electronic structure calculations of molecular interaction with
statistical sampling of the canonical ensemble using the CP2K simulation code. A 16-
molecule cell was sampled using the PBE functional with a TZVP basis set. The
progression of the average structure and fluctuations across the phase transition will be
presented and their consequences in the interpretation of NMR lineshape analysis and
neutron powder diffraction pair distribution function. This work was supported by the
                              s
U.S. Department of Energy' (DOE) Office of Basic Energy Sciences, Chemical Sciences
program and the Hydrogen Fuel Initiative. The Pacific Northwest National Laboratory is
operated by Battelle for DOE.
                                      W – 29




           Investigation of MgH2 and LiBH4 Mixtures with Potential for
                               Hydrogen Storage

                     Uncharat Setthanan and G. Sean McGrady,
               University of New Brunswick, Fredericton, NB, Canada
                              E-mail:uncharat@unb.ca


Activation of MgH2 with small amounts of LiBH4 results in superior H2 uptake and
release behaviour compared with the pure binary hydride [1]. We have explored a range
of mixtures of MgH2 and LiBH4 at various mole ratios; these showed no reduction below
the desorption temperature of MgH2. A 3:1 mixture prepared by ball milling gives the
best performance, releasing 5.6 wt. % H2 around 350 °C, as shown in Figure 1. Doping
this mixture with small amounts of TiCl3 reduces the desorption temperature by around
50 °C, and produces a system with high reversibility and fast kinetics. The doped 3:1
mixture is fully rechargeable at H2 pressures less than 5 bar.




Figure 1. Hydrogen desorption behaviour of MgH2 and LiBH4 mixtures



1. S.R. Johnson, P.A. Anderson, P.P. Edwards, I. Gameson, J.W. Prendergast, M. Al-
Mamouri, D. Book, I.R. Harris, J.D. Speight and A. Walton, Chem. Commun. 2005,
2823.
                                       W – 30




      Hydrogen Absorption Studies In Transition Metal Ethylene Complexes

                         A.B. Phillips and B.S. Shivaram*
       Department of Physics, University of Virginia, Charlottesville, VA 22901
                           *E-mail: bss2d@virginia.edu


Transition metals(TM) ethylene complexes were created by ablating various TM in an
ethylene atmosphere in a pulsed laser deposition chamber. The ability of such complexes
to absorb hydrogen was investigated through surface acoustic wave based techniques.
We find evidence that the Ti-ethylene complex does indeed have the potential to absorb
the predicted 14 weight % hydrogen when ultra high purity gas (UHP 99.999% pure H2)
is used. However, we also find evidence for a reduction of this percentage when the UHP
hydrogen passed through a cryogenic trap is employed. Studies on hydrogen absorption
depending on gas purity in such TM-ethylene complexes will be reported.
                                        W – 31




           Ammonia Borane Derivatives for Chemical Hydrogen Storage

  Roshan P. Shrestha, Himashinie V. K. Diyabalanage, Troy A. Semelsberger, Mark E.
                          Bowden and Anthony K. Burrell*
               Materials Physics and Applications- Materials Chemistry
   Los Alamos National Laboratory Mail Stop J514, Los Alamos NM 87545 (USA)
          rshrestha@lanl.gov, Phone: (505) 667-3588, Fax: (505) 667-9905.


The derivatives of Ammonia Borane (AB) have been explored as potential chemical
hydrogen storage materials. These derivatives were chosen to address the current
challenges facing the use of AB for hydrogen storage-which include the formation of
thermodynamically stable products such as Boron Nitride, and release of volatile
compounds such as borazine during thermal treatment. Composites of AB with a range of
metal salt additives have been prepared and characterized using X-ray powder diffraction,
thermal analyses, and 11B NMR and IR spectroscopies. Hydrogen release in the order of
7.5-10 wt % per AB molecule was measured.
                                               W – 32




       Mixed Borohydride-Alanates as potential Hydrogen Storage Materials

 Christopher I. Smitha, Martin O. Jonesa, Simon R. Johnsona, William I. F. Davidb, Peter
                                       P. Edwardsa.
  a
    Inorganic Chemistry Laboratory, University of Oxford, South Parks Road, Oxford,
                                      OX1 3QR, UK.
       b
         ISIS Facility, Rutherford Appleton Laboratory, Chilton, OX11 0QX, UK.
                             christopher.smith@chem.ox.ac.uk


The lack of a suitable hydrogen storage material is a major technological barrier to a
future hydrogen economy. Sodium Alanate (NaAlH4) is a promising solid state hydrogen
store as it doesn’t require complex chemical reactions to recharge its hydrogen content.
                                       o
                                  C
                        6NaAlH 4 180→ 2Na 3 AlH 6 + 4Al + 6H 2
                                           o
                        2Na 3 AlH 6 > 200→ 6NaH + 2Al + 3H 2
                                      C
                                   o
                        6NaH > 400→ 6Na + 3H 2
                               C

The decomposition temperature of NaAlH4 (>200oC)[1] is considered too high for
practical applications but it may be possible to lower this decomposition temperature
through the formation of new structures based on that of NaAlH4. To that end we present
results of our studies on the reactions of NaAlH4 with NaBH4.

We report a new phase, of composition Na4Al3BH16, formed
on reacting a 1:1 ratio of NaAlH4 and NaBH4 in a sealed capillary.
Modelling synchrotron x-ray data indicates this new phase to be a
2x2x2 superstructure of NaBH4, in the Pa-3 space group with
a = b = c = 13.38Å.


 [1] B. Bogdanovic and M. Schwickardi, Journal of Alloys and
 Compounds 1997, 253-254, 1-9.




                                                                             Figure 1: NaAlH4
                                         W – 33




      IGAn: In-situ Gravimetric Neutron Diffraction Studies of Hydrogen Storage
                                     Materials

     W.I.F. David,a,b M. Sommariva,a R.M. Ibberson,a M.O. Jones,b S.R. Johnson,b P.P.
    Edwards,b G. F. Duffy,c M.G. Roper,c M.E. Jackson,c A.P. Woodhead,c M.J. Benhamc
a
    ISIS Facility, Rutherford Appleton Laboratory, Chilton, Didcot, Oxon., UK OX11 0QX
b
    Inorganic Chemistry Laboratory, University of Oxford, South Parks Road, Oxford, UK
                                          OX3 3QR
          c
            Hiden Isochema Ltd, 231 Europa Boulevard, Warrington, UK WA5 7TN
                                email: m.sommariva@rl.ac.uk


Hydrogen storage is one of the key technological barriers in the transition to a hydrogen-
based economy. Solid state storage, for instance by metal hydrides, offers the potential
for safe and efficient storage. However, no material currently exists that fulfils all the
stringent requirements of an ideal solid hydrogen store. Simultaneously combining high
storage capacity (>6 wt% hydrogen) with a relatively low release-temperature (<150oC),
complete reversibility of the thermal absorption/desorption cycle and finally low toxicity
/ low cost is a difficult conundrum. All these scientific factors are intimately linked to
the crystal structure of the hydrogen store and thus understanding hydrogenation requires
a full structural description coupled with a detailed study of the physical-chemical
properties of the absorption/desorption process of the system. To achieve this, we have
recently developed a system that allows us to perform structural and gravimetric
measurements simultaneously on the GEM and HRPD diffractometers at ISIS. The
system, named IGAn (Intelligent Gravimetric Analyzer for Neutrons) was constructed by
Hiden Isochema Ltd. We report here our initial commissioning measurements on the
benchmark system Mg/MgD2 along with detailed absorption and desorption studies of
Li3N - Li2ND - LiND2.
                                         W – 34




The Role of Vibrational Coupling in Understanding the Thermodynamics of
                           Hydride Formation

    Ashley C. Stowe1, Monika Hartl2, Alice Acatrinci2, Luke Daemen2, Donald
                              Anton1, Ragaiy Zidan1
       1
         Energy Security Directorate, Savannah River National Laboratory,
                                Aiken, SC 29808;
 2
   Manuel Lujan, Jr. Neutron Scattering Center, Los Alamos National Laboratory,
                             Los Alamos, NM 87545
                       E-mail: Ragaiy.Zidan@srnl.doe.gov


The search for materials with ever higher hydrogen storage capacities has utilized the
Edisonian approach of alloying or combining various known hydrogen storage materials
in the hopes of identifying new high capacity compounds. There have been some notable
successes over the years. These new materials are categorized as AxBy compounds, in
which a very stable hydride, A type, is alloyed with an unstable, B type, hydride, forming
a novel material with intermediate thermodynamics. LaNi5H6, TiFeH2 and Mg2NiH6 are
notable examples of AB5, AB, and A2B compounds respectively. This general
phenomenon can be applied to complex metal hydrides as well. For instance, NaAlH4 can
be thought of as a combination of very stable NaH and unstable AlH3, which indeed
results in thermodynamics which are intermediate to its progenitors’, resulting in a
metasable phase having useful hydrogen storage thermodynamics. Similarly, NaMgH3 is
the result of combining NaH and MgH2 and should have properties intermediate to these
well known species. Incoherent inelastic neutron scattering has been conducted to
understand the phonon vibrations of these complex metal hydrides, as they relate to
altering the hydrogenation thermodynamics. Comparison has been made with the
neutron vibrational spectrum both reagents (NaH and MgH2 in the case of NaMgH3) in
order to further understand the nature of hydrogen bonding in the ternary material. The
incoherent inelastic neutron scattering (IINS) measurements of NaMgH3 have also
revealed that the structure is rhombohedral rather than the published orthorhombic
structure. These two unit cells are mathematically identical; however, the rhombohedral
structure yields vibrations which reflect the observed IINS spectrum within an
experimental error. Vibrational spectroscopy is a useful tool to probe the nature of the
interaction of hydrogen in these metastable hydrides which may guide future synthetic
endeavors in the search for novel hydrogen storage materials.
                                            W – 35




               Design of materials for storing hydrogen in quasi-molecular form

                         Qiang Sun 1, 2, Qian Wang 1, and Puru Jena 1
         1
         Physics Department, Virginia Commonwealth University, Richmond, VA 23284
 2
   Department of Advanced Materials and Nanotechnology, Peking University, Beijing 1000871,
                                             China


Synthesis of materials capable of storing hydrogen with large gravimetric and volumetric
density and operating at near ambient thermodynamic conditions is critical to the success of
a hydrogen economy. Carbon based materials due to their light weight have been regarded
as possible candidates for hydrogen storage. Recent works suggested that carbon
nanostructures such as fullerenes, organic molecules, and nanotubes suitably functionalized
with transition metal atoms can meet the hydrogen storage requirements. These materials
store hydrogen in quasi-molecular form with binding energies intermediate between
physisorbed and chemisorbed states. However, the stability of these materials has been a
problem to deal with since transition metal atoms have a tendency to cluster and hence
adversely affect the hydrogen storage capability. We have considered two classes of
materials where this limitation can be avoided. These include coating of carbon
nanostructures with Li where the low cohesive energy of Li does not induce clustering.
Unfortunately, the binding energy of hydrogen on Li coated fullerenes is very small and
cryogenic temperatures are needed. A second class of materials where metal atoms can be
prevented from clustering and yet store hydrogen with a binding energy around 0.5 eV/H2
molcule involves silsesquioxanes (SQ) nano complex [RSiO3/2]n with R= -C5H5. Grafting
of cyclopentadienyl on this complex totally changes its electronic structure and chemistry.
Cyclopentadienyl becomes a reactive site where a transition-metal atom (e.g., Sc) can be
doped and the metal atoms serve as an effective adsorption site for hydrogen molecules.
Because of the strong bonding of transition metal atoms to the SQ complex, they are
prevented from clustering. This nano complex has the following advantages: (1) Storage
capacity in the fully grafted case is 5 wt% where hydrogen is bound quasi-molecularly with
a binding energy of about 0.6 eV /H2 molecule. (2) The structure of SQ itself is stable, and
the synthesis is very flexible. These results are obtained using density functional theory and
generalized gradient approximation for exchange and correlation. We hope that our
prediction of the effectiveness of functionalized SQ complex as a hydrogen storage
material will encourage experimental investigation.

1. Q. Sun, Q. Wang , and P. Jena, Nano Letters 5 (2005) 1273
2. Q. Sun , Q. Wang, P. Jena, and Y. Kawazoe, J. Am. Chem. Soc.127, (2005)14582
3. Q. Sun, P. Jena, Q. Wang, and M. Marquez, J. Am. Chem. Soc. 128, (2006) 9742
  4. Q. Sun, Q. Wang, P. Jena, B. V. Reddy, and M. Marquez , Chem. Mater., 19, 3074 (
  2007)
                                          W – 36




           Catalytic Dehydrogenation of Carborane on a Platinum Surface

                     Aashani Tillekaratne and Michael Trenary
    Department of Chemistry, University of Illinois at Chicago, 845 W Taylor Street,
                                Chicago, IL 60607
                       Submitting author: mtrenary@uic.edu


The techniques of reflection absorption infrared spectroscopy (RAIRS) and temperature
programmed desorption (TPD) have been used to explore the dehydrogenation on a
Pt(111) surface of 1,2-dicarba-closo-dodecaborane, C2B10H12, also known simply as
carborane. Complex hydrides, such as the boranes and carboranes, are of interest as
possible hydrogen storage materials because of their high hydrogen content. Many
hydrides are quite stable and catalysts are needed to promote the release of hydrogen at
low temperatures. The carbon and boron atoms of the C2B10H12 carboranes occupy the
vertices of a slightly distorted icosahedron and have a hydrogen weight percentage of 8.3.
There are three isomers of these icosahedral carboranes, of which the ortho form (the 1,2
isomer) is the most readily available. The icosahedral structure of the boron-carbon cage
structure of carborane is also adopted by the boron-rich solid boron carbide. The
similarity in the structures of carborane and boron carbide has led to the successful use of
carborane as a precursor gas for the growth of boron carbide thin films. However, the
detailed mechanism by which carborane dehydrogenates to form boron carbide has not
been previously investigated. At submonolayer coverages at 85 K the RAIRS spectrum of
carborane displays strong B-H stretching vibrations near 2600 cm-1, and a weak C-H
stretch at 3090 cm-1 that indicate molecular adsorption at low temperature. The molecule
is stable on the surface up to 250 K, where it is transformed into a new intermediate with
a strongly red-shifted B-H stretch vibration at 2507 cm-1. This intermediate is stable up to
400 K, above which no B-H stretch vibrations are observed. Hydrogen is released in
stages as the carborane monolayer is heated from 85 to 800 K, which is also indicative of
the formation of partially hydrogenated surface intermediates. Further analysis of the data
may permit definitive identification of the surface intermediates formed during the course
of carborane dehydrogenation on the Pt(111) surface.
                                         W – 37




   Lithium-Decorated Carbon Nanoframeworks Tailored for Hydrogen Storage

Philippe F. Weck1, Eunja Kim2, Naduvalath Balakrishnan1, Hansong Cheng3, and Boris I.
                                           Yakobson4
                    1
                      Dept. of Chemistry, University of Nevada Las Vegas,
            2
              Dept. of Physics and Astronomy, University of Nevada Las Vegas,
                               3
                                 Air Products and Chemicals, Inc.,
 4
   Dept. of Mechanical Engineering and Materials Science and Dept. of Chemistry, Rice
                                           University.
                                     weckp@unlv.nevada.edu


Based on first-principles calculations, we propose a novel class of 3-D materials
consisting of small diameter single-walled carbon nanotubes (SWCNTs) functionalized
by organic ligands as potential hydrogen storage media. Specifically, we have carried out
density functional theory calculations to determine the stable structures and properties of
nanoframeworks consisting of (5,0) and (3,3) SWCNTs constrained by phenyl spacers.
Valence and conduction properties, as well as normal modes, of pristine nanotubes are
found to change significantly upon functionalization, in a way that can serve as
experimental diagnostics of the successful synthesis of the proposed framework
structures. Ab initio molecular dynamics simulations indicate that such systems are
thermodynamically stable for on-board hydrogen storage. In order to increase the
hydrogen uptake in the interstitial cavity of such nanoframeworks, we are currently
investigating the possibility of Li deposition on these nanostructures.




                                                  Figure: Electronic charge density of a
                                                  framework consisting of (5,0) SWCNTs
                                                  constrained by phenyl spacers. The value
                                                  of the isosurface corresponds to 0.2
                                                  electrons/Å3 [Weck et al., Chem. Phys.
                                                  Lett. 439, 354 (2007)].




This work was supported by DOE grant DE-FG36-05G085028.
                                          .W – 38




     A Novel Organometallic Fe-C60 Complex for Vehicular Hydrogen Storage

E. Whitney, A. C. Dillon, C. Engtrakul, C. J. Curtis, K. J. O’Neill, P. A. Parilla, K. Jones,
           L. J. Simpson, M. J. Heben, Y. Zhao, Y.-H. Kim, and S. B. Zhang
               National Renewable Energy Laboratory, Golden, Colorado
                                erin_whitney@nrel.gov


A hydrogen-based energy economy could supply a pollution-free closed cycle that relies
entirely on renewable resources. However, one of the biggest challenges in the
development of a hydrogen economy is that of onboard vehicular hydrogen storage. To
this end, new fullerene coordination chemistry and synthetic techniques have been
demonstrated for a Fe-C60 complex as a potential hydrogen storage material. This work
is based on theoretical studies of a Sc-C60 structure that is predicted to have a reversible
hydrogen capacity of ~7 wt%. This new complex has been characterized with solid state
nuclear magnetic resonance (NMR) spectroscopy, Raman spectroscopy, X-ray diffraction
(XRD), transmission electron microscopy (TEM), and temperature-programmed
hydrogen desorption (TPD). Analysis of the iron-fullerene complex indicates the
formation of C60-Fe-C60-Fe-C60 chain structures of an undetermined length, with a
reversible hydrogen capacity of ~0.5 wt% at 77 K and 2 bar after degassing to 200 °C.
For the as-synthesized sample, the BET surface area is ~10 m2/g. Interestingly, the BET
surface area increases to ~50 m2/g after degassing, which is still an order of magnitude
less than expected given the measured experimental hydrogen capacity. Nitrogen and
hydrogen isotherms performed at 75 K also show a marked selectivity for hydrogen over
nitrogen for this complex.
                                          W – 39




     Energetics and Kinetics of Ti Clustering on Neutral and Charged C60 Surfaces

                 Shenyuan Yang1,2, Mina Yoon2,3, Enge Wang1, Zhenyu Zhang3,2
1
    International Center for Quantum Structures and Institute of Physics, Chinese Academy
                                   of Sciences, Beijing, China
     2
       Department of Physics and Astronomy, The University of Tennessee, Knoxville, TN
                                             37996
       3
         Materials Science and Technology Division, Oak Ridge National Laboratory, Oak
                                        Ridge, TN 37831


Recent theoretical studies have shown that Ti decorated carbon nanotubes and fullerenes
may serve as promising media for hydrogen storage. However, how to prevent the
clustering of metal adsorbents remains a big challenge. In this talk, we investigate the
energetics and kinetics of Ti clustering on both neutral and charged C60 surfaces, based
on first-principles calculations. We find that there exists a critical size of five below
which Ti two-dimensional (2D) layer structures are preferred to three-dimensional (3D)
clusters. Hole- and B- doping greatly enhance Ti binding to fullerene surfaces and lead to
stronger dispersion of Ti atoms. But the critical size remains unchanged at moderate
charge states or just slightly increases by B-doping. However, the formation of 3D cluster
is hindered by a high kinetic energy barrier in the process of a single Ti atom climbing up
a single Ti layer. The energy barrier is even higher on B-doped fullerene and will
stabilize larger 2D structures at low temperatures.
                                              W – 40




              Charged Fullerenes as High Capacity Hydrogen Storage Media1

                 Mina Yoon1,2, Shenyuan Yang3,2, Enge Wang3, Zhenyu Zhang1,2
  1
    Materials Science & Technology Division, Oak Ridge National Laboratory, Oak Ridge, TN
  37831 2Department of Physics and Astronomy, The University of Tennessee, Knoxville, TN
 37996 3International Center for Quantum Structures and Institute of Physics, Chinese Academy
                               of Sciences, Beijing 100080, China


     Using first-principles calculations within density functional theory, we study hydrogen
storage in carbon fullerenes by functionalizing such structures with tunable charge states. The
tunability is achieved via chemical or electron doping. Our study shows that with the proper
method of charge doping, the hydrogen binding strength can be substantially increased for
potential room-temperature, near ambient applications. The enhanced binding is delocalized in
nature, surrounding the whole surface of a charged fullerene, and is attributed to the polarization
of the hydrogen molecules by the high electric field generated near the surface of the charged
fullerene. At full hydrogen coverage, these charged fullerenes can gain storage capacities of up
to ~8.0wt%. We also find that, contrary to intuitive expectation, fullerenes containing
encapsulated metal atoms only exhibit negligible enhancement in the hydrogen binding strength,
because the charge donated by the metal atoms is primarily confined inside the fullerene cages.
These predictions may prove to be instrumental in searching for a new class of high capacity
hydrogen storage media.


[1] Mina Yoon, Shenyuan Yang, Enge Wang, and Zhenyu Zhang, Nano Lett. (in press, 2007).
AUTHOR INDEX
A
Abramov, A.V.        M-15                Böttger, A.J.       W-19
Acatrinci, A.        W-34                Bowden, M.          M-4
Adams, T.            O-15, W-2           Bowden, M.E.        W-31
Ahn, C.              O-8                 Bowen, K.H.         M-20
Ahuja, R.            W-27                Bowman, Jr., R.C.   O-28
Aieta, N.V.          O-13                Bradshaw, R.W.      M-36
Aken, B.B. van       W-19                Brown, C.           W-11
Akiyama, T.          O-23, M-33          Brown, I.           M-4
Alapati, S.V.        O-47, W-12          Buchter, F.         M-5, M-42
Alibeyli, R.         W-1                 Buckley, P.         W-10
Ambrosini, A.        O-35, M-31          Buratto, S.K.       W-3
Anderson, P.A.       M-8                 Burgert, R.         M-20
Anton, D.            W-34                Burrell, A.K.       M-13, W-31
Araújo, C.M.         W-27                Burress, J.         W-10
Atta, S.L.V.         O-18                Bussian, D.A.       W-3
Autrey, T.           O-26, O-27, M-4,
                     M-25, W-11, W-22,   C
                     W-28                Cai, M.             W-7
                                         Camaioni, D.        W-22
B                                        Cavicchi, R.E.      M-12
Babu. S, N.          M-7                 Cepel, R.           W-10
Balachandran, U.B.   M-32                Chakraborty, S.     O-19, M-27
Balakrishnan, N.     W-37                Chapelle, D.        M-6, M-7
Balaprasad, A.       M-18                Chater, P.A.        M-8
Bär, M.              M-35                Chaudhuri, S.       M-9
Barker, S.           W-10                Chen, G.            M-1
Barkhordarian, G.    O-36, W-23          Chen, L.            M-10, M-32
Barton, K.           O-12                Chen, P.            O-25
Behrens, Jr., R.     M-36                Cheng, H.S.         O-44, W-37
Benham, M.           W-10                Cho, H.             W-22
Benham, M.J.         W-33                Cho, H.M.           O-27, W-28
Bennington, S.       M-30, W-14          Choi, D.W.          W-4
Bérubé, V.           M-1                 Choudhury, B.       O-12
Besenbacher, F.      O-6, M-34           Christensen, C.H.   O-24, M-16
Bhat, V.V.           M-2                 Chun, K.            W-4
Billups, W.E.        O-19, M-27          Cleary, T.G.        M-37
Blake, C.            O-41                Colbe, J.B.v.       O-36
Blencoe, J.G.        M-3                 Contescu, C.I.      M-2
Book, D.             W-21                Cook, L.P.          M-12
Borgschulte, A.      O-38                Cooper, A.          O-44
Borgshulte, A.       M-5                 Cornelius, A.       M-26, M-29
Bormann, R.          O-36, W-16, W-23    Cornelius, C.J.     O-35
Bösenberg, U.        O-36                Cui, Y.Y.           W-5
Curtin, D.             O-12                Ford, M.             O-44
Curtis, C.J.           O-9, W-38           Fujimoto, C.H.       O-35

D                                          G
Daemen, L.             M-26, W-11, W-22,   Gallego, N.C.        M-2
                       W-34                Ganteför, G.F.       M-20
Dai, B.                O-47, W-12          Garino, T.           M-31
Dam, B.                O-29                Ge, Q.F.             M-19
Dash, R.K.             O-16                Gelbard, F.          M-31
David, W.I.F.          O-45, W-15, W-20,   Gemma, R.            W-24
                       W-32, W-33          Gislon, P.           M-21
Davis, B.L.            M-13                Goddard, III, W.A.   O-14
Dec, S.F.              O-13                Gogotsi, Y.          O-16
Dedrick, D.E.          M-36                Gorte, R.J.          O-33
Dillon, A.C.           O-9, W-38           Graetz, J.           M-9
Diyabalanage, H.V.K.   M-13, W-31          Green, M.L.          M-12
Dolotko, O.            M-14                Gross, A.F.          O-18
Doppiu, S.             O-36                Grubisic, A.         M-20
Dornheim, M.           O-36, W-16, W-23    Gutfleisch, O.       O-36, W-13
Dorris, S.E.           M-32                Gutowski, M.         M-15
Dresselhaus, M.        M-1
Dresselhaus, M.S.      O-1                 H
Duffy, G.F.            W-33                Haije, W.G.          W-19
Duin, A. van           O-14                Harris, I.R.         W-21
                                           Hartl, M.            M-26, W-11, W-22,
E
                                                                W-34
Edie, M.J.             M-15                Hartman, M.          W-11
Edwards, D.            M-39                Hauge, R.H.          O-19, M-27
Edwards, P.P.          O-45, W-5, W-15,    Heben, M.J.          O-9, W-38
                       W-20, W-32, W-33    Heldebrant, D.       M-4
Egelhoff, W.F.         M-12                Herring, A.M.        O-13
Eigen, N.              O-36, W-16          Heske, C.            M-35
Eliezer, D.            O-39, M-17          Hess, N.             M-4, W-11, W-22
Engtrakul, C.          O-9, W-38           Hess, N.J.           O-27, W-28
Enyashin, A.           M-23                Hino, S.             M-28
Escobedo, G.           O-12                Hiraki, T.           O-23, M-33
Evans, I.C.            M-8                 Horan, J.L.          O-13
                                           Huang, C. P.         M-41
F                                          Hummelshøj, J.S.     M-16
Fan, H.                O-19, M-27          Humphries, T.        W-18
Fernandez-Alonso, F.   W-14                Hutton, A.           M-40
Figiel, H.             M-7                 Hwang, S.-J.         O-28
Filipek, S.M.          M-18
Fischer, J.E.          O-16
                                       Klerke, A.             M-16
I                                      Knudsen, J.            O-6, M-34
Ibberson, R.M.     W-33                Kojima, Y.             M-28
Ibrahimo lu, B.    W-1                 Konstandopoulos, AG.   O-4
Ichikawa, T.       M-28                Koratkar, N.           M-10
Ignatov, A.        M-9                 Korinko, P.S.          O-15, W-2
Inouye, A.         O-43, M-38          Kraaft, G.             M-40
Ishikiriyama, M.   O-31, W-17          Kubas, G.J.            O-20
                                       Kuc, A.                M-23
J                                      Kudo, A.               O-5
                                       Kuliyev, S.            W-1
Jackson, M.E.      W-33
                                       Kumar, R.              M-26
Jain, A.           M-21
                                       Kumar, R.S.            M-29
Jain, I.P.         M-21
                                       Kuo, M.-C.             O-13
Jang, S.S.         O-14
                                       Kurban, Z.             M-30
Jash, P.           M-22
Jena, P.           O-11, O-17, M-10,   L
                   M-20, M-24, W-27,
                   W-35                Laudisio, G.           O-16
Jensen, T.         O-36, W-23          Lee, H.M.              W-4
Johnson, J.K.      O-47, W-12          Lee, T.H.              M-32
Johnson, S.R.      O-45, W-15, W-20,   Leonard, A.D.          O-19, M-27
                   W-32, W-33          Li, H.W.               O-37
Jones, I.P.        W-21                Li, J.                 M-15
Jones, K.          W-38                Li, R.Y.               W-7
Jones, M.O.        O-45, W-5, W-15,    Li, S.                 O-17
                   W-20, W-32, W-33    Li, X.                 M-20
Joswig, J.-O.      M-23, W-6           Liu, J.J.              M-19
Jung, U.H.         W-4                 Liu, P.                O-18
                                       Liu, R.S.              M-18
K                                      Llamas-Jansa, I.       W-13
Kabbour, H.        O-8                 Łodziana, Z.           M-5, M-42
Kandalam, A.K.     M-24                Lovell, A.             W-14
Kaplan, Y.         W-1                 Lowton, R.L.           W-15, W-20
Karkamkar, A.      M-25, W-11          Lozano, G.             O-36, W-16
Kathmann, S.       W-11
Kathmann, S.M.     O-27, W-28
                                       M
Keller, C.         W-16                Mahajan, S.            M-39
Kemmitt, T.        M-4                 Majzoub, E.            W-26
Kim, E.            M-26, M-29, W-37    Mamontov, E.           W-11
Kim, S.H.          W-4                 Mann, V.               W-21
Kim, Y.-H.         O-9, W-38           Marcano, D.            W-24
Kiran, B.          M-20, M-24          Marchi, C.S.           O-40
Kittrell, C.       O-19, M-27          Marsh, N.D.            M-37
Klassen, T.        O-36, W-23          Marshall, S.L.         M-3
Masci, A.          M-21               Pan, C.C.              M-11
Mat, M.D.          W-1                Parilla, P.A.          O-9, W-38
Matsunaga, T.      O-31, W-17         Park, K.T.             W-4
Matsuo, M.         O-37               Parvanov, V.           O-27, W-11, W-22,
Mauron, Ph.        M-5                                       W-28
Mavrikakis, M.     O-34               Pasquali, M.           O-19, M-27
McGrady, G.S.      W-18, W-29         Paster, M.             O-2
Melis, A.          O-21               Paul-Boncour, V.       M-18
Merinov, B.        O-14               Pecharsky, V.K.        M-14
Metiu, H.          W-3                Perreux, D.            M-6, M-7
Metz, O.           O-36               Perry, R.              O-12
Miwa, K.           O-37               Pez, G.                O-44
Moen, C.D.         M-36               Pfeifer, P.            W-10
Montgomery, C.B.   M-12               Phillips, A.B.         W-30
Mori, D.           O-31, W-17         Picciolo, J.J.         M-32
Mundy, C.          O-27, W-11, W-28   Pistidda, C.           O-36, W-23
Muradov, N.        M-41               Pobst, J.              W-10
Myneni, G.         M-40               Podeyn, M.             O-36, W-23
                                      Portet, C.             O-16
N                                     Proffen, T.            W-11, W-22
Nagata, S.         O-43, M-38, W-8    Prosini, P.P.          M-21
Nakamori, Y.       O-37               Pundt, A.              W-24
Nanu, D.E.         W-19
Nayak, S.K.        M-10
                                      R
Nenoff, T.M.       M-31               Radtke, G.             M-1
Nickels, E.A.      W-20               Raissi-T, A.           M-41
Nicol, M.          M-26               Ramirez-Cuesta, A.J.   W-25
Nikitin, E.        W-24               Ranasinghe, A.D.       W-3
Nørskov, J.K.      M-16               Rassat, S.             M-4
Nörthemann, K.     W-24               Remhof, A.             M-5, M-42
Nwakwuo, C.        O-36, W-23         Remick, R.             O-42
                                      Reves, J.B.            M-16
O                                     Robinet, P.            M-6
O'ea, J.R.
 D                 W-3                Rongeat, C.            W-13
Ohba, N.           O-37               Rönnebro, E.           W-26
Okinaka, N.        O-23, M-33         Roper, M.G.            W-33
O'eill, K.J.
 N                 O-9, W-38          Roth, M.               W-10
Orimo, S.-I.       O-37
Osswald, S.        O-16
                                      S
Ozolins, V.        O-30               Saha, M.S.             W-7
                                      Saito, K.              W-8
P                                     Salguero, T.T.         O-18
Paik, B.           W-21               Sato, T.               O-37
Paja, A.           M-7                Sattler, C.            O-4
                                      Scheicher, R.H.        W-27
Schenck, P.K.        M-12
Schenter, G.         W-11, W-22         T
Schenter, G.K.       O-27, W-28         Takamura, H.       O-22
Schlenkrich, F.      W-24               Tange, K.          M-28
Schmidt, H.K.        O-19, M-27         Thiébaud, F.       M-6
Schnadt, J.          O-6, M-34          Tillekaratne, A.   W-36
Schneider, S.        W-24               Toseland, B.       O-44
Schnöckel, H.-G.     M-20               Tour, J.M.         O-19, M-27
Scott, A.            O-44               Towata, S.-I.      O-37
Scott, B.L.          M-13               Trenary, M.        M-22, W-36
Seifert, G.          M-23, W-6          Tsuchiya, B.       O-43, M-38, W-8
Semelsberger, T.A.   M-13, W-31         Tucker, M.G.       W-19
Seok, H.             O-16               Turner, J.A.       O-3
Setthanan, U.        W-29
Sha, Y.              O-14               U
Shah, P.             W-10
                                        Uchida, H.         W-24
Shaw, W.             M-25, W-22, M-4
                                        Udovic, T.J.       O-46
Shaw, W.J.           O-27, W-28
                                        Uesugi, H.         O-23, M-33
Sheptyakov, D.       M-42
Shewchun, Dr. J.     M-39               V
Shikama, T.          O-43, M-38, W-8
Shinozawa, T.        O-31, W-17         Vajo, J.J.         O-18
Shivaram, B.S.       M-40, W-30         Vang, R.T.         O-6, M-34
Sholl, D.S.          O-47, W-12         Vegge, T.          M-16
Shrestha, R.P.       M-13, W-31         Vente, J.F.        W-19
Simpson, L.J.        O-9, W-38          Voecks, G.         O-14
Singer, J.P.         O-16               Vogel, S.          M-26
Singhal, S.C.        O-32
Skipper, N.          M-30, W-14         W
Smith, C.I.          W-32               Wagner, S.         W-24
Smith, R.            W-14               Walton, A.         W-21
Somerday, B.         O-40               Wang, E.G.         W-39, W-40
Sommariva, M.        O-45, W-20, W-33   Wang, Q.           O-11, W-35
Sørensen, R.Z.       M-16               Washio, K.         O-31, W-17
Steele, A.M.         O-4                Weck, P.F.         W-37
Stephens, R.D.       O-18               Weinhardt, L.      M-35
Stobbe, P.           O-4                Wexler, C.         W-10
Stokes, S.T.         M-20               Whitney, E.        O-9, W-38
Stowe, A.            M-25, W-11         Wierzbicki, R.     M-18
Stowe, A.C.          M-26, W-34         Wood, M.           W-10
Sugiura, H.          M-18               Woodhead, A.P.     W-33
Suleiman, M.         W-24
Sun, A.X.            W-7                Y
Sun, Q.              O-11, W-35         Yaghi, O.M.        O-7
Suppes, G.           W-10               Yakobson, B.I.     W-37
Yamamoto, S.    O-43, M-38
Yang, H.D.      M-18
Yang, S.Y.      W-39, W-40
Yildirim, T.    O-10, O-16
Yoon, M.        W-39, W-40
Yu, R.H.        M-11
Yu, T.          O-14
Yushin, G.      O-16

Z
Zhang, H.       M-14
Zhang, J.Z.     M-26
Zhang, S.B.     O-9, W-38
Zhang, Y.       M-10
Zhang, Z.Y.     W-39, W-40
Zhao, Y.        O-9, W-38
Zhao, Y.S.      M-26
Zhevago, N.K.   O-39, M-17
Zhou, X.Y.      W-9
Zhou, Y.        O-36
Zidan, R.       W-34
Züttel, A.      O-38, M-5, M-42
ORGANIZATION

Chairman: Puru Jena (U.S.A)

INTERNATIONAL ADVISORY BOARD

Frank DiSalvo (Cornell University, USA)
Mildred Dresselhaus (M.I.T, USA)
Peter Edwards (University of Oxford, U.K)
Constantina Filiou (JRC, Netherlands)
Ronald Griessen (Vrije Universiteit, Netherlands)
Maciej Gutowski (Heriot-Watt University, U.K)
Craig Jensen (University of Hawaii, USA)
Thomas Klassen (Helmut-Schmidt-University, Germany)
Nathan Lewis (California Institute of Technology, USA)
Laurie Mets (University of Chicago, USA)
Jens Norskov (CAMP, Denmark )
Shin-ichi Orimo, (Tohoku University, Japan)
Louis Schlapbach (EMPA, Switzerland)
Omar Yaghi (University of California at LA, USA)

NATIONAL PROGRAM COMMITTEE

Michelle Buchanan (Oak Ridge National Laboratory)
Anne Dillon (National Renewable Energy Laboratory)
Peter Eklund (Pennsylvania State University)
Karl Johnson (University of Pittsburgh)
Scott Jorgensen (General Motors)
Vitalij Pecharsky (Ames Laboratory)

LOCAL ORGANIZING COMMITTEE

Gang Chen (Virginia Commonwealth University)
Anil K. Kandalam (Virginia Commonwealth University)
Sa Li (Virginia Commonwealth University)
Qiang Sun (Virginia Commonwealth University)
Qian Wang (Virginia Commonwealth University)
Mary Willis (Virginia Commonwealth University)
Kiran Boggavarapu (McNeese State University)