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O: Fachverband Oberflächenphysik
O 85: Poster Session - Supported Nanoclusters: Structure, Reactions, Catalysis
O 85.2: Poster
Mittwoch, 18. März 2020, 18:15–20:00, P2/EG
Hydrogenation of small organic molecules with size-selected Ptn clusters supported on thin-film SiO2 and MgO — •Tobias Hinke, Marian Rötzer, Maximilian Krause, Andrew Crampton, and Ueli Heiz — Technische Universität München, Ernst-Otto-Fischer Straße 1, D-85748 Garching bei München
To gain fundamental understanding in heterogeneous catalysis processes, model systems and associated reactions, e.g. in UHV, are useful tools. Transition metal clusters on a single crystal and metal oxide support constitute highly tunable systems. The high degree of surface uniformity of metal single crystals governs an epitaxial growth of metal oxide thin-films, forming a suitable support, which are capable of modeling bulk oxide supports. Transition metal clusters with up to 50 atoms show significant, non-scalable size-effects. Additional properties of the support, like acidity, reducibility, film thickness and interfacial support interactions, in conjunction with the crystal (local) work function affect the cluster polarization. This induces a change in surface charge density, an important quantity for metal cluster reactivity. The activity and the change of the structural sensitivity of size-selected Ptn-clusters (n=9, 10, 13) supported on SiO2 and MgO thin-films are studied. Activity and structure sensitivity towards the hydrogenation of small organic molecules (ethylene and acetylene) as a model reaction are evaluated. Activity is monitored by pulsed molecular beam reactive scattering and temperature programmed desorption experiments. Characterization is performed through electronic (AES, MIES, UPS) and vibrational (IRRAS) spectroscopy.