Regensburg 2010 – wissenschaftliches Programm
Bereiche | Tage | Auswahl | Suche | Downloads | Hilfe
O: Fachverband Oberflächenphysik
O 27: Metal subtrates: Adsorption of O and/or H
O 27.8: Vortrag
Dienstag, 23. März 2010, 12:15–12:30, H42
Effects of substituted palladium on hydrogen adsorption to stepped Au(111) surfaces — •Jonathan E. Mueller1,2, Sudha Venkatachalam1, and Timo Jacob1 — 1Ulm University, Albert-Einstein-Allee 47, D-89069 Ulm, Germany — 2Materials and Process Simulation Center, California Institute of Technology, Pasadena, California 91125, United States of America
Configurations of different Pd-containing Au(111) bimetallic surfaces with Pd substituents varying from one to three atoms have been studied using density functional theory. The stability of the so-formed Pd monomers, dimers or trimers in the surface and subsurface layers of a Au(111) terrace and their influence on the adsorption of hydrogen have been investigated [1]. We find that before hydrogen adsorption the surface prefers to form Pd monomers over dimers or trimers located in subsurface positions, which is in agreement with experimental observations. However, adsorption of atomic hydrogen reverses this trend, leading to a stabilization of Pd trimers over dimers or monomers all located in the surface layer. Since realistic surfaces usually contain step edges, we extended our studies to the (100) and (111) steps of Au(111), finding that Pd does prefer substituting Au at bulk sites over edge sites, a behavior again modified by the presence of surface hydrogen [2].
[1] S. Venkatachalam, T. Jacob, Phys. Chem. Chem. Phys., 11, 3263-3270 (2009) [2] J. E. Mueller, S. Venkatachalam, T. Jacob, in preparation.