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O: Fachverband Oberflächenphysik

O 41: Poster Session I (Semiconductor Substrates: Epitaxy and growth; Semiconductor Substrates: Adsorbtion; Semiconductor Substrates: Solid-liquid interfaces; Semiconductor Substrates: Clean surfaces; Oxides and insulators: Epitaxy and growth; Oxides and insulators: Adsorption; Oxides and insulators: Clean surfaces; Organic, polymeric and biomolecular films - also with adsorbates; Organic electronics and photovoltaics, Surface chemical reactions; Heterogeneous catalysis; Phase transitions; Particles and clusters; Surface dynamics; Surface or interface magnetism; Electron and spin dynamics; Spin-Orbit Interaction at Surfaces; Electronic structure; Nanotribology; Solid/liquid interfaces; Graphene; Others)

O 41.66: Poster

Dienstag, 23. März 2010, 18:30–21:00, Poster B1

Rate oscillations in the O2 + H2 reaction on a Rh(111) surface alloyed with nickel — •Tim Smolinsky, Florian Lovis, and Ronald Imbihl — Institut für Physikalische Chemie und Elektrochemie, Leibniz-Universität Hannover, Callinstr. 3-3a, D-30167 Hannover, Germany

A Rh(111)/Ni surface with Ni in the submonolayer range was prepared by decomposing Ni(CO)4 at the Rh(111) surface. After characterization with low energy electron diffraction (LEED) and Auger electron spectroscopy the surface was subjected to the O2 + H2 reaction using photoemission electron microscopy (PEEM) as spatially resolving method. On a clean Rh(111) surface the O2 + H2 reaction is a bistable system. The alloying with nickel changes the system into an excitable medium. The reaction was studied in the 10-7 - 10-4 mbar range at temperatures between 300 and 700 °C. With PEEM chemical wave patterns involving simple reaction fronts have been observed. Under particular reaction conditions spiral waves and target patterns can be triggered. These spatiotemporal patterns were accompanied by rate oscillations observed with mass-spectrometry.