Autocatalysis by the intermediate surface hydroxide formed during hydrogen peroxide reduction on silver electrodes

Recent electrochemical studies of the cathodic reduction of hydrogen peroxide (H2O2) on silver electrodes in acidic electrolyte (HClO4) revealed a novel autocatalytic reaction path. Adsorbed hydroxyl groups, OHad, were proposed to act as the catalyst. To gather further clarity about this mechanism, in particular about the presence and nature of the postulated adsorbate OHad, in the present work surface science experiments on Ag(1 1 1) electrodes are evaluated. It is concluded that the species OHad is identical with the surface AgOH formed in alkaline solution as a relatively stable intermediate in the anodic oxidation of OH− to surface-Ag2O.