Oxygen reduction on the Au (311) electrode surface in alkaline electrolyte

Abstract

Oxygen reduction was studied for the first time using a single crystal electrode in a rotating disc-ring arrangement. The Au (311) surface shows a complex behaviour, with a very high activity in certain potential regions. The first electron transfer is rate determining in the region of 4-electron reduction. As with Au (100), a 4 e- reduction changes into a 2 e- process, which reverts back to a 4 e-reaction at very negative potentials. Based on a general reaction scheme of O2 reduction, a map of the operating potential dependent reaction pathways was constructed. Nearly 60% of the mass flux of O2 undergoes a direct reduction to OH- in the region of mixed control. The high activity of Au (311) was ascribed to a high step density and AuOH present on its surface.