Regensburg 2010 – scientific programme

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O: Fachverband Oberflächenphysik

O 41: Poster Session I (Semiconductor Substrates: Epitaxy and growth; Semiconductor Substrates: Adsorbtion; Semiconductor Substrates: Solid-liquid interfaces; Semiconductor Substrates: Clean surfaces; Oxides and insulators: Epitaxy and growth; Oxides and insulators: Adsorption; Oxides and insulators: Clean surfaces; Organic, polymeric and biomolecular films - also with adsorbates; Organic electronics and photovoltaics, Surface chemical reactions; Heterogeneous catalysis; Phase transitions; Particles and clusters; Surface dynamics; Surface or interface magnetism; Electron and spin dynamics; Spin-Orbit Interaction at Surfaces; Electronic structure; Nanotribology; Solid/liquid interfaces; Graphene; Others)

O 41.50: Poster

Tuesday, March 23, 2010, 18:30–21:00, Poster B1

In-situ XPS and reactivity studies on different Au/TiO2 catalyst systems — •Martina Hank, Karif Dumbuya, Ole Lytken, Piotr Bobrowski, Bernhard Arnold, J. Michael Gottfried, and Hans-Peter Steinrück — Universität Erlangen-Nürnberg, Lehrstuhl für Physikalische Chemie II, Egerlandstr. 3, 91058 Erlangen, Germany

Nano-sized gold on oxidic substrates shows a high activity in heterogeneous catalysis which sharply contrasts the inertness of bulk gold. The origin of the catalytic activity and the nature of the active sites are still discussed controversially: Quantum size effects, low coordinated gold atoms, the substrate/gold perimeter interface or anionic as well as cationic gold species have been considered as possible candidates. We have studied surfaces of different gold-based catalysts using X-ray photoelectron spectroscopy (XPS) under ultra high vacuum conditions as well as with in-situ XPS in the presence of reactive gases (CO, O₂, propene and mixtures thereof) at pressures of up to 1mbar. These model systems include a Au/TiO₂ reference powder catalyst, a Au/TiO₂(110) planar model catalyst and a TiO₂/Au(111) inverse model catalyst. Comparison of the latter systems enables us to discriminate between cluster-size and interface related effects. Furthermore, we will discuss a novel reaction cell, which is used to study the activity of different model catalysts under ambient pressure conditions.

This work is supported by the DFG through grant GO 1812/1-1 and by the Cluster of Excellence "Engineering of Advanced Materials"