Regensburg 2013 – scientific programme

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O: Fachverband Oberflächenphysik

O 46: Nanostructures and Clusters

O 46.3: Talk

Wednesday, March 13, 2013, 11:00–11:15, H45

First-principles study of the interaction and charge transfer between gold clusters and TiO₂ nano-structures — •Chunsheng Liu, Ran Jia, Harald Oberhofer, and Karsten Reuter — TU München, Germany

Recent experimental studies of catalysis on small (TiO₂)_m-Au_n hetero-clusters [J. Phys. Chem. A 115, 11479 (2011)] have opened up a new direction in the search for efficient, yet stable (photo-)catalysts for reactions such as CO oxidation or water splitting. They have shown a strong dependence of the reactivity on the atomic stoichiometry of the catalyst clusters, including an especially pronounced even/odd behavior with respect to the number of Au atoms. In our contribution we discuss our findings - gained from ab initio global geometry optimization - leading to a theoretical understanding of the observed properties of nano-scale (TiO₂)_m-Au_n hetero-clusters. Analogous to experiment, we find an even/odd behavior of the coated clusters’ HOMO-LUMO gap and charge transfer from the coating Au atoms, which in turn influences the clusters’ reactivities. Finally, we compare these properties of the (TiO₂)_m-Au_n hetero-clusters to those of small gold Au_n particles adsorbed on extended TiO₂ surfaces, in order to gauge how much of the observed behavior is due to the limited size of the TiO₂ substrate cluster.