Generation of active surface states of gold and the role of such states inelectrocatalysis

The cyclic voltammetry behaviour of gold in aqueous media is often regarded in very simple terms as a combination of two distinct processes, double la yer charging/discharging and monolayer oxide formation/removal. This view i s questioned here on the basis of both the present results and earlier inde pendent data by other authors. It was demonstrated in the present case that both severe cathodization or thermal pretreatment of polycrystalline gold in acid solution resulted in the appearance of substantial Faradaic respons es in the double layer region. Such anamolous behaviour, as outlined recent ly also for other metals, is rationalized in terms of the presence of activ e metal atoms (which undergo premonolayer oxidation) at the electrode surfa ce. Such behaviour, which is also assumed to correspond to that of active s ites on conventional gold surfaces, is assumed to be of vital importance in electrocatalysis; in many instances the latter process is also quite marke d in the double layer region.