THE TIME-RESOLVED EQCM AND STUDY OF THE KINETICS OF SILVER(I) OXIDE FORMATION ON A POLYCRYSTALLINE SILVER ELECTRODE IN ALKALINE-SOLUTION

The time-resolved EQCM method is described and a theoretical analysis of the relation between the frequency resolution and the sampling rate (time resolution) is presented. It is shown that the time-resolved EQ CM can fulfil simultaneously good frequency resolution and time resolu tion. The kinetics of the oxidation of Ag to Ag2O are studied using th is method combined with the potentiostatic technique. The monolayer Ag 2O formed at the first stage shows a potential dependent coverage. In the first two stages, the Ag2O layer thickens layer by layer with a ra te-determining step of diffusion of Ag+ transients associated with the formation of the bulk phase Ag2O are well consistent with the current transients, and both indicate an instantaneous nucleation and 3D grow th mechanism. A relatively accurate method to estimate the mean height h of the cavities at the rough surface is also presented based on the frequency transient and charge density, and a linear increase of h wi th anodic charge is observed during the potentiostatic process. It has been demonstrated that the time-resolved EQCM can provide valuable in formation on the transient change of the morphology at the electrode/e lectrolyte interface.