Dresden 2011 – wissenschaftliches Programm

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O: Fachverband Oberflächenphysik

O 15: Nanostructures at surfaces: Dots, particles, clusters, arrays I

O 15.6: Vortrag

Montag, 14. März 2011, 16:15–16:30, WIL C107

Supported silver and copper clusters for photocatalysis — •Vladimir Popok, Ingo Barke, Antje Neubauer, Stefan Lochbrunner, and Karl-Heinz Meiwes-Broer — Institut für Physik, Universität Rostock, Universitätsplatz 3, 18051 Rostock, Germany

Nanometer-sized metal particles deposited onto surfaces are of significant interest for applications in catalysis. In the current study, nanoparticles of silver and copper in the size range from ca. 5 to 18 nm were formed using arc-discharge and magnetron sputtering cluster ion sources and deposited on silica glass substrates. The prepared cluster-assembled samples have been studied in order to increase the efficiency of existing catalytic schemes for hydrogen production, which is of high practical importance. In particular, Ir photosensitizers (PS) in combination with palladium, platinum or iron catalysts are known to be promising systems for reduction of aqueous protons to hydrogen. We deposited the PS on cluster-covered samples and studied their optical properties. It is found that in presence of metal clusters the ligand-centered optical transitions of the PS are significantly increased accompanied by a change of the photoluminescence. These findings indicate considerable effect of the metal nanoparticles on the electronic structure of the PS, a fact that might be of relevance for the improvement of photo-catalytic reactions.