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The anodic oxidation of Ag2O to AgO in normal aqueous potassium hydroxide solution was investigated quantitatively under both galvanostatic and potentiostatic conditions at 25 °C. A few results for similar experiments in N/40 KOH are also reported. Tafel slopes and other parameters were determined. The experimental results show the dependence of current density as a hyperbolic function of overpotential, i.e. i = 2i0sinh (λFη/2RT). The electron number λ was found to be 2 and the symmetry factor β was confirmed to be 1/2. It is proposed that the rate-determining step for the formation of AgO from Ag2O occurs at the Ag2O/AgO interface and involves the transfer of O−2ions.

An experimental study of the kinetics for the electrochemical formation of AgO from Ag2O in aqueous alkaline solutions was reported in an earlier paper (1). The proposed mechanism for the rate-determining step was suggested to be the transfer of oxide ions across the mixed oxide interface. Further theoretical possibilities under Langmuir and Temkin conditions of surface coverages are considered here in the light of the previously obtained experimental data. In particular we examine the possibilities of the rate-determining step involving adsorbed ionic intermediates on the AgO/Ag2O electrode at the oxide/electrolyte interface. For the Temkin conditions, the intrinsic and induced heterogeneity models of Conway and his co-workers have been applied to our calculation of Tafel slopes. None of the mechanisms at the oxide/electrolyte interface were found to be rate-controlling.