Dresden 2011 – wissenschaftliches Programm

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O: Fachverband Oberflächenphysik

O 86: Heterogeneous catalysis I

O 86.2: Vortrag

Donnerstag, 17. März 2011, 16:45–17:00, WIL B122

Au/TiO₂(110) model catalysts on stoichiometric supports: Size dependence of the Au nanoparticles and activation energy in the CO oxidation reaction — •Menhild Eyrich, Joachim Bansmann, and R. Jürgen Behm — Ulm University, Institute of Surface Chemistry and Catalysis, 89069 Ulm, Germany

Since the late 1980s numerous studies on Au nanoparticles on metal oxide supports were carried out. Due to the low conductivity of fully oxidized TiO₂(110) supports which hinders many surface science based methods such as STM, most investigations were carried out on reduced TiO₂(110) supports. The catalytic activity of planar Au/TiO₂(110) model catalysts depends, in analogy to the respective powder catalysts, strongly on the size of the Au nanoparticles and on the pretreatment of the catalyst or the catalyst support. Here, we report the experimental results from a study on fully oxidized planar Au/TiO₂ model catalysts with fully oxidized TiO₂(110) support materials performed at different Au coverages (i.e., different particle size) and different temperatures. The strong influence of the size of the Au nanoparticles on the catalytic activity was studied at different temperatures showing a less pronounced size dependence (but very high activity) at low temperatures (around room temperature). Then, the activation energy was determined for different particle sizes, in the size regime of the high catalytic activity (small Au nanoparticles) and for larger Au nanoparticles. The results will be compared to results for other (reduced) Au/TiO₂ model and for powder catalysts.