Stuttgart 2012 – wissenschaftliches Programm
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A: Fachverband Atomphysik
A 46: Cluster
A 46.3: Vortrag
Freitag, 16. März 2012, 11:00–11:15, V38.02
Activation of oxygen on small cationic platinum clusters in the gas phase — •Christian Kerpal1, Dan Harding1, Alexander Hermes2, Suzanne Hamilton2, Robert Moffatt2, Stuart Mackenzie2, Gerard Meijer1, and André Fielicke1 — 1Fritz-Haber-Institut der Max-Planck-Gesellschaft, Faradayweg 4-6, 14195 Berlin — 2Department of Chemistry, University of Oxford, South Parks Road, Oxford, OX1 3QZ, UK
Small clusters of platinum represent model systems for potentially important industrial catalysts, e.g. for the activation of C-H bonds and for fuel cells. The long term goal of such cluster model studies is to understand the chemistry occurring at specific low coordinated metal sites in heterogeneous catalysis. However, the properties of metal clusters often differ dramatically with particle size. As most of the physical and chemical properties of clusters are directly related to their geometries, the determination of the precise structure is essential. The combination of infrared multiple photon dissociation (IR-MPD) spectroscopy and density functional theory (DFT) calculations provides a means to get detailed knowledge of the structures of both bare metal clusters and the adsorption geometries of small ligands on the clusters. Here we present IR-MPD spectra of PtnO2m+ clusters for n ≤ 6; m = 1, 2 and a comparison to DFT calculations, allowing structural determination for the cluster-ligand complexes. These structures give direct information on the activation of the oxygen, showing different types of molecular and dissociated binding and in some cases a mixture of both, depending on cluster size and oxygen coverage.