Hostname: page-component-7479d7b7d-m9pkr Total loading time: 0 Render date: 2024-07-14T21:35:31.388Z Has data issue: false hasContentIssue false

In situ high pressure XRD study on hydrogen uptake behavior of Pd-carbon systems

Published online by Cambridge University Press:  01 February 2011

Vinay V Bhat
Affiliation:, Oak Ridge National Laboratory, Oak Ridge, TN, 37830, United States
Nidia C Gallego
Affiliation:, Oak Ridge National Laboratory, Oak Ridge, TN, 37830, United States
Cristian I Contescu
Affiliation:, Oak Ridge National Laboratory, Oak Ridge, TN, 37830, United States
E Andrew Payzant
Affiliation:, Oak Ridge National Laboratory, Oak Ridge, TN, 37830, United States
Adam J Rondinone
Affiliation:, Oak Ridge National Laboratory, Oak Ridge, TN, 37830, United States
Halil Tekinalp
htekina@CLEMSON.EDU, Clemson University, Clemson, SC, 29634, United States
Dan D Edie
Affiliation:, Clemson University, Clemson, SC, 29634, United States
Get access


Efficient storage of hydrogen for use in fuel cell-powered vehicles is a challenge that is being addressed in different ways, including adsorptive, compressive, and liquid storage approaches. In this paper we report on adsorptive storage in nanoporous carbon fibers in which palladium is incorporated prior to spinning and carbonization/activation of the fibers. Nanoparticles of Pd, when dispersed in activated carbon fibers (ACF), enhance the hydrogen storage capacity of ACF. The adsorption capacity of Pd-ACF increases with increasing temperature below 0.4 bar, and the trend reverses when the pressure increases. To understand the cause for such behavior, hydrogen uptake properties of Pd with different degrees of Pd-carbon contact (Pd deposited on carbon surface and Pd embedded in carbon matrix) are compared with Pd-sponge using in situ XRD under various hydrogen partial pressures (<10 bar).

Rietveld refinement and profile analysis of diffraction patterns does not show any significant changes in carbon structure even under 10 bar H2. Pd forms β PdH0.67 under 10 bar H2, which transforms to α PdH0.02 as the hydrogen partial pressure is decreased. However, the equilibrium pressure of transition (corresponding to a 1:1 ratio of α and β phases) increases with increasing the extent of Pd-carbon contact. This pressure is higher for Pd embedded in carbon than for Pd deposited on carbon surface. Both these Pd-carbon materials have higher H2 desorption pressure than pure Pd, indicating that carbon “pumps out” hydrogen from PdHx and the pumping power depends on the extent of Pd-carbon contact. These results support the spillover mechanism (dissociative adsorption of H2 followed by surface diffusion of atomic H).

Research Article
Copyright © Materials Research Society 2008

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)


1. Schlapbach, L. and Züttel, A., Nature, 414, 353 (2001)Google Scholar
2. Rosi, N. L., Eckert, J., Eddaoudi, M., Vodak, D. T., Kim, J., O'Keeffe, M., Yaghi, O. M., Science, 300, 1127 (2003)Google Scholar
3. Wu, X., Gallego, N. C., Contescu, C. I., Tekinalp, H., Bhat, V. V., Baker, F. S., Thies, M. C., and Edie, D. D., Carbon (2007), Carbon, 46, 54 (2008)Google Scholar
4. Aga, R. S., Fu, C. L., mar, M. Kr, Morris, J. R., Phys. Rev. B. 76, 165401 (2007)Google Scholar
5. Robell, A. J., Ballou, E. V. and Boudart, M., J. Phys. Chem. 68, 2748 (1964)10.1021/j100792a003Google Scholar
6. Boudart, M., Aldag, A. W., Vannice, M. A., J. Catalysis, 18, 46 (1970)10.1016/0021-9517(70)90310-6Google Scholar
7. Lueking, A. and Yang, R. T., Appl. Cat. A: General, 265, 259 (2004)Google Scholar
8. Yang, F. H., Lachaweic, A. J., Yang, R. T., J. Phys. Chem. B, 110, 6236 (2006)Google Scholar
9. Zacharia, R., Kim, K. Y., Kibria, A. K. F. M., Nahm, K. S., Chem. Phys. Letters, 412, 369 (2005)Google Scholar
10. Basova, Y. V., Edie, D. D., Lee, Y. S., Reid, L. K., Ryu, S. K., Carbon, 42, 485 (2004)Google Scholar
11. Maeland, A. J. and Gibbs, T. R. P. Jr, J. Phys. Chem. 65, 1270 (1961)Google Scholar
12. Owen, E. A. amd Williams, E. St. J., Proc. Phys. Soc., 56, 52 (1944)Google Scholar
13. Lachaweic, A. J., Qi, G. and Yang, R. T., Langmuir, 21, 11418 (2005)10.1021/la051659rGoogle Scholar
14. Jain, P., Fonseca, D. A., Schaible, E. and Leuking, A. D., J. Phys. Chem. C., 111, 1788 (2007)Google Scholar
15. Jewell, L. L. and Davis, B. H., Appl. Cat. A: General, 310, 1 (2006)Google Scholar