Berlin 2008 – wissenschaftliches Programm
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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.