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O: Fachverband Oberflächenphysik

O 13: Heterogeneous Catalysis

O 13.9: Vortrag

Montag, 25. Februar 2008, 16:00–16:15, HE 101

Interaction of CO, CO₂, O₂ and H₂O with Au/Rutile TiO₂(011)-(2x1)/Re(1010) model catalysts — •Wilhelmine Kudernatsch¹, Karifala Dumbuya², J. Michael Gottfried², Hans-Peter Steinrück², and Klaus Christmann¹ — ¹Physikalische und Theoretische Chemie, Freie Universität Berlin, Germany — ²Lehrstuhl für Physikalische Chemie II, Friedrich-Alexander-Universität Erlangen-Nürnberg, Germany

During the last decade, the peculiar activity of Au/titania catalysts for low-temperature CO oxidation has stimulated a wealth of studies using TiO₂ model catalyst systems. In a first step, we have studied the epitaxy and chemical properties of titanium dioxide films grown on rhenium surfaces under ultra-high vacuum (UHV) conditions. Titania films were prepared by co-deposition of Ti vapor in an O₂ atmosphere of 1x10⁻⁶ mbar at 900 K. On Re(1010), this procedure results in the growth of rutile films terminated by a (2x1)-reconstructed (011) surface. Au-containing model catalyst systems were then prepared by controlled vapor deposition of Au onto these films.

In order to characterize the structural and chemical properties of our model catalyst surfaces, we have studied the adsorption of CO, CO₂, and H₂O on the clean and Au-covered TiO₂(011)-(2x1) films by means of temperature-programmed desorption (TPD) and low-energy electron diffraction (LEED). To obtain information about the chemical composition of the model catalysts in the presence of the reactants, CO and O₂, we performed in-situ measurements with high-pressure X-ray photoelectron spectroscopy (XPS) at pressures up to 1 mbar.