Following Composition Changes in Gold Oxides Through Abnormal Peak Potential Shifts

Abstract Amorphous metal oxide surfaces play a key role in electrocatalysis. Yet at present we know very little about the atomic structure of these amorphous metal oxide surfaces and the precise phenomena occurring at the liquid solid interface of these materials. Here we show that under oxidative conditions Au3+ cations are constantly being formed within amorphous gold oxide, and that these are the main cause for previously not understood phenomena such as potential shifts of the oxide reduction peaks. The Au3+ cations play a crucial role in the chemistry of gold oxide, where these form bonds with nucleophiles present within the amorphous gold oxide layer and the electrolyte solution, thereby dominating the interactions at the solid-liquid interface. Moreover we show that these exposed cationic sites play a crucial role not only in the structure of the solid-liquid interface but also actively take part in the catalytic water oxidation reaction.