Regensburg 2007 – wissenschaftliches Programm

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O: Fachverband Oberflächenphysik

O 57: Surface Chemical Reactions and Heterogeneous Catalysis II

O 57.1: Vortrag

Donnerstag, 29. März 2007, 15:45–16:00, H38

Determination of the CO adsorption energy on Au/TiO₂ model catalysts at elevated pressures — •Thomas Diemant, Joachim Bansmann, and Rolf Jürgen Behm — Institute of Surface Chemistry and Catalysis, Ulm University, D-89069 Ulm

The adsorption of CO on Au/TiO₂/Ru(0001) model catalysts has been studied by in-situ IR measurements at elevated pressures up to 50 mbar. From a quantitative analysis of the integrated IR intensities it is possible to calculate the CO adsorption energy on the Au particles of the model catalyst surface. We have determined the CO adsorption energy with this method for pure CO and for CO/O₂ mixtures using model catalysts with different Au coverages. Comparing the results for both gas compositions, we can quantify the influence of (co-adsorbed) oxygen on the CO adsorption. From the results for different Au coverages, the influence of the Au particle size on the CO binding strength is derived. The results of this study will be compared to results of UHV studies on the CO adsorption of Au model catalysts using either TPD measurements or a similar analysis of IR results.