Oxygen reduction at chalcogenide model surfaces

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Carbon supported Ru-Se nanoparticles have been widely studied as catalysts for oxygen reduction, because of their insensitivity towards poisoning by methanol. However, completely missing are fundamental studies on well defined single crystalline surfaces of Se modified Ru, although the surface structure of these can be determined more accurately than that of nanoparticles. With the lack of knowledge about the surface structure of these catalysts, one can only speculate about their mechanism of action. In this project, it is therefore intended to prepare well defined surfaces of Ru (and also Rh) modified by Se (and also S, Te) through adsorption at different potentials, or from the gas phase at different temperatures, possibly followed by an annealing step. The different catalyst surfaces shall be characterised mainly by STM and XPS. The number of active Ru (Rh) sites shall be titrated by adsorption of CO and metal upd (e.g. of Gu). The catalytic activity shall be tested by DEMS and the rotating ring disc electrode assembly.