Dresden 2009 – wissenschaftliches Programm
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O: Fachverband Oberflächenphysik
O 45: Heterogeneous catalysis
O 45.10: Vortrag
Donnerstag, 26. März 2009, 12:45–13:00, SCH A215
Similarities and Differences of the Reactivity of Pt/Au(111) and Pd/Au(111) towards HER/HOR, ORR and MOR — •Holger Wolfschmidt1, Rainer Bußar1,2, and Ulrich Stimming1,2 — 1TU München, Garching, Deutschland — 2ZAE Bayern, Garching, Deutschland
Nanoparticles and nanostructures often show a different behavior compared to the bulk material. Especially in the field of catalysis high reactivity and low amounts of catalyst are required. Thereby, well known noble metal catalysts such as Pt and Pd were electrochemically deposited onto inert Au(111) supports. These nanostructured model surfaces allow investigating the effects of particle dispersion, particle size and the influence of the substrate material. The following reactions were investigated: I.) hydrogen evolution reaction (HER), II.) hydrogen oxidation reaction (HOR), III.) oxygen reduction reaction (ORR) and IV.) methanol oxidation reaction (MOR). Electrochemical methods such as pulse techniques and cyclic voltammetry were used to determine the electrocatalytic properties. The morphology of the model electrodes and the amount of noble metal was obtained with EC-STM. It was found that with decreasing amount of Pd and Pt deposited onto Au(111) the specific activity towards hydrogen related reactions increases by up to three orders of magnitude. In contrast to the strong enhancement for the hydrogen reactions the ORR shows an increasing electrocatalytic activity with increasing amount of noble metal as one would expect. The specific reactivity of Pt on Au(111) for the MOR seems to behave also in an expected way.