A study of the electrocatalytic behaviour of gold in base using ac voltammetry

Abstract

In-phase, faradaic ac responses were recorded for gold in base, under potential sweep conditions, at quite low potentials: the results support the view that premonolayer oxidation is a significant feature of this sytem. It was concluded that variations, with the degree of oxidation, of the activity of both the reduced and oxidized state of the low coverage interfacial couple caused major broadening of the reversible response for the adatom/incipient hydrous oxide transition in the double layer region of this system. A survey was carried out of a range of electrocatalytic processes, both oxidations and reductions, previously investigated by dc cyclic voltammetry. The observed ac responses support the view that incipient hydrous oxide species play an important role, both as mediators and inhibitors, in such reactions. In most cases the behaviour of gold in base is only explicable in terms of the premonolayer, hydrous oxide approach.