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Why is Gold such a Good Catalyst for Oxygen Reduction in Alkaline Media?

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  • Financial support by the Deutsche Forschungsgemeinschaft (Schm 344/34-1,2, SCHM 344/42-1,2, Sa 1770/1-1,2, and FOR 1376), by the European Union under ELCAT, and by CONICET (PIP 112-201001-00411), and by PICT-2008-0737 (ANPCyT) are gratefully acknowledged. We thank CONICET, Argentina, for continued support. A generous grant of computing time from the Baden-Württemberg grid is gratefully acknowledged.

Abstract

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The two faces of gold: The reduction of oxygen on gold electrodes in alkaline solutions has been investigated theoretically. The most favorable reaction leads directly to adsorbed O2, but the activation energy for a two-step pathway, in which the first step is an outer-sphere electron transfer to give solvated O2, is only slightly higher. d-band catalysis, which dominates oxygen reduction in acid media, plays no role. The reason why the reaction is slow in acid media is also explained.

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