Regensburg 2007 – wissenschaftliches Programm
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O: Fachverband Oberflächenphysik
O 44: Poster Session II (Semiconductors; Oxides and Insulators: Adsorption, Clean Surfaces, Epitaxy and Growth; Surface Chemical Reactions and Heterogeneous Catalysis; Surface or Interface Magnetism; Solid-Liquid Interfaces; Organic, Polymeric, Biomolecular Films; Particles and Clusters; Methods: Atomic and Electronic Structure; Time-resolved Spectroscopies)
O 44.74: Poster
Mittwoch, 28. März 2007, 17:00–19:30, Poster C
Adsorption of Au on Rutile TiO2(011)-(2x1) and (110) films grown on Rhenium Host Surfaces — •Susanne Roth, Wilhelmine Kudernatsch, Dirk Rosenthal, and Klaus Christmann — Institut für Chemie und Biochemie, FU-Berlin, Germany
In order to bridge the materials gap in heterogeneous catalysis and to mimic catalyst supports with increasing complexity, we have studied the epitaxy and chemical properties of titanium dioxide films grown with different surface termination on Re(1010) and Re(0001) host surfaces, respectively. Titania films with a defined stoichiometry and long-range order were prepared by co-deposition of Ti vapor in an O2 atmosphere at elevated temperatures (T ≥ 830 K). Thus, a unique pg(2x2) LEED phase with a characteristic glide mirror plane is formed on Re(1010), with intermediate faceting. XRD and LEED reveal that the films consist of rutile terminated by a (2x1)-reconstructed (011) phase. On Re(0001), deposition of TiO2 leads to hexagonal LEED patterns indicating the growth of three domains of rutile(110) rotated by 120∘ against each other. In a finite coverage range, faceting is observed (as with the Re(1010) surface) pointing to a Stranski-Krastanov type of growth for both Re surfaces. Model catalyst systems were then prepared by vapor deposition of Au onto the rutile films. Results on the growth and properties of the Au crystallites on TiO2(110)/Re(0001) using LEIS, XPS and TPD will be presented. Furthermore, we will compare the adsorption of CO, CO2 and H2O on the Au-titania surfaces with the respective adsorption on the bare TiO2(011)-(2x1) films.