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O: Fachverband Oberflächenphysik
O 60: Poster Session IV (Solid/liquid interfaces; Semiconductors; Oxides and insulators; Graphene; Plasmonics and nanooptics; Electronic Structure; Surface chemical reactions; Heterogeneous catalysis)
O 60.121: Poster
Mittwoch, 16. März 2011, 17:30–21:00, P4
Ceria promoted CO oxidation on Pt(111): Oxygen-spillover and active border concept — Stefan Becker1, •Kathleen Müller1, Rafal Wróbel1,2, and Helmut Weiss1 — 1Otto-von-Guericke-University Magdeburg, Institute of Chemistry, Universitätsplatz 2, D-39106 Magdeburg, Germany — 2West Pomeranian University of Technology, Institute of Chemical and Environmental Engineering, Pulaskiego 10, 70-322 Szczecin, Poland
The influence of CeOx nanoformations on the heterogeneously catalysed CO oxidation above the bistable region was investigated. A well-defined CeOx/Pt(111) model catalytic system with homogeneous 2D islands has been produced by evaporating Ce on Pt(111) in oxygen (5·10−8 mbar). The clean Pt(111) surface was characterised by XPS, LEED and STM and the inverted model catalysts CeOx/Pt(111) by XPS, STM and CO titration. The temperature and pressure dependency of the reaction rate was analysed via mass spectrometry. An enhanced reactivity was observed for a surface covered with CeOx islands as compared to clean Pt(111). The CeOx leads to a change in the adsorption characteristics for oxygen as well as for carbon monoxide (promotional effects). An active border concept for oxygen and carbon monoxide and a spillover mechanism for oxygen are suggested.