AVS 55th International Symposium & Exhibition
    Surface Science Tuesday Sessions
       Session SS-TuP

Paper SS-TuP1
A Study of a Hydrogen Atom on Pd-Ag Alloy Surfaces Via First Principles Calculation

Tuesday, October 21, 2008, 6:30 pm, Room Hall D

Session: Surface Science Poster Session
Presenter: N. Ozawa, Osaka University, Japan
Authors: N. Ozawa, Osaka University, Japan
T. Roman, Osaka University, Japan
H. Nakanishi, Osaka University, Japan
H. Kasai, Osaka University, Japan
Correspondent: Click to Email

Technology for extracting hydrogen gas with high purity from natural gases is necessary for the establishment of a hydrogen fuel system. At present, since materials used for permeable films such as Pd are rare and expensive, a fundamental understanding about reaction processes of hydrogen on metal surfaces is necessary for developing an alternative material replacing with them. On the time, we have studied the elementary reaction processes of a hydrogen atom on Pd surfaces and its subsurface1-4 using first principles calculations. In particular, we have given focus on quantum mechanical behaviors of the hydrogen atom motion, which appear due to the small mass of hydrogen. In this study, we investigate the quantum states of the hydrogen atom on the PdAg alloy surface and in its subsurface by calculating the wave functions and the eigen energies for the hydrogen atom motion within the framework of the variation method on an adiabatic potential energy surface (PES) obtained from the first principles calculations.5,6 From these researches, we discuss the behavior of the hydrogen atom such as adsorption and diffusion. We find that the adsorption energy of the hydrogen atom on the surface and activation energy for diffusion into the subsurface area are smaller than on pure Pd surfaces. In this conference, we also discuss the hydrogen atom behavior on the other kinds of Pd-based alloy surfaces.

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2K. Nobuhara, H. Kasai, W. A. Diño, H. Nakanishi and A. Okiji, Jpn. J. Appl. Phys. 42, 4630(2003).
3N. B. Arboleda Jr., H. Kasai, K. Nobuhara, W. A. Diño, and H. Nakanishi, J. Phys. Soc. Jpn. 73, 745 (2004).
4N. Ozawa, N. B. Arboleda Jr., K. Nobuhara, W. A. Dino, H. Nakanishi and H. Kasai, J. Appl. Phys. 101, 123530 (2007).
5N.Ozawa, N. B. Arboleda Jr., T. A. Roman, W. A. Diño, H. Nakanishi and H. Kasai, J. Phys.: Condens. Matter 19, 365214 (2007).
6N. Ozawa, N. B. Arboleda Jr., H. Nakanishi, S. Shimoji, and H. Kasai, Surf. Interface Anal. In print.