Dresden 2011 – wissenschaftliches Programm

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

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 60.118: Poster

Mittwoch, 16. März 2011, 17:30–21:00, P4

Gold-containing model catalysts studied with in-situ XPS — •Martina Pistor, Karifala Dumbuya, Ole Lytken, Lorenz Ringel, Jörg Michael Gottfried, and Hans-Peter Steinrück — Universität Erlangen-Nürnberg, Lehrstuhl für Physikalische Chemie II

The noble metal gold, if supported as nanoparticles on oxides such as TiO₂, is a promising catalyst for many oxidation reactions. Up to now, it is still debated why gold, which is not active as a bulk material, becomes active in the dispersed state (with optimum particle sizes 2-5 nm). Explanations include quantum size effects, low-coordinated gold atoms, the substrate/gold perimeter interface and anionic as well as cationic gold species. Using in-situ X-ray photoelectron spectroscopy (XPS), we have studied various gold-based powder catalysts and model catalysts, both in the presence of CO, O₂ and propene and under ultrahigh vacuum conditions. The studied systems include gold nanoparticles supported on TiO₂(110) and titania nanoparticles supported on Au(111) as well as reference powder catalysts. Depending on the experimental conditions, especially the oxygen partial pressure, the intrinsic catalytic activity of the system is superimposed by X-ray-induced effects such as the formation of gold oxide. On the basis of these beam damage effects, we will discuss possible limitations of in-situ XPS. This work is supported by the DFG through grant GO 1812/1 and by the Cluster of Excellence “Engineering of Advanced Materials” granted to the Universität Erlangen-Nürnberg.