Regensburg 2013 – wissenschaftliches Programm

Bereiche | Tage | Auswahl | Suche | Aktualisierungen | Downloads | Hilfe

O: Fachverband Oberflächenphysik

O 20: Surface Chemical Reactions and Heterogeneous Catalysis II

O 20.7: Vortrag

Montag, 11. März 2013, 17:30–17:45, H33

Addressing structural and catalytic properties of bimetallic surface alloys using kinetic Monte Carlo — •Luis Mancera and Axel Groß — Institute of Theoretical Chemistry, University of Ulm, D-89069 Ulm, Germany

Using CO as a probe of the local reactivity, it has been experimentally shown that catalytic activity in PdAg/Pd(111) bimetallic surface alloys is mainly driven by the configuration of Pd adsorption sites.[1] Based on density functional theory (DFT) calculations, these ensemble effects have been theoretically confirmed for the same surface alloy, whereas a mutual cancellation of ligand and strain effects has been obtained from the analysis of local density of d-states.[2] Since an unexpected dependence of the local reactivity and the formation enthalpy on the subsurface layers has been also found from the DFT calculations, in particular for the case of low silver concentrations at the surface combined with complete silver layers at the subsurface, we address here the effect of diffusion of silver atoms to the sublayers. In order to obtain a more detailed understanding of the catalytic properties by including a wider set of structural configurations, we present in this contribution first steps towards DFT-based kinetic Monte Carlo calculations of bimetallic surface alloys, using PdAg/Pd(111) as a model system.

[1] Y. Ma et al. Phys. Chem. Chem. Phys. 13, 10741 (2011)

[2] L. A. Mancera et al. Phys. Chem. Chem. Phys., accepted for publ., DOI:10.1039/C2CP42914D, (2012)