Structure and activity relations in the hydrogen peroxide reduction at silver electrodes in alkaline NaF/NaOH electrolytes

The electrochemical interface between polycrystalline silver and alkaline N aF/NaOH electrolytes at various pH values has been studied by means of cycl ic voltammetry and ac-impedance spectroscopy. Hydroxide electrochemisorptio n has been observed in a wide potential range (between -1.1 and 0 V SCE dep ending upon pH). Study of the hydrogen peroxide reduction at silver rotatin g-disc electrodes in alkaline NaF/NaOH electrolytes has proved the existenc e of a slow chemical step in the reaction mechanism, its rate being strongl y affected by the submonolayer surface oxidation. The reaction scheme is pr oposed for the hydrogen peroxide reduction, which takes into consideration the structure of the adsorbate layer at the electrode;electrolyte interface at the variable potential. (C) 1998 Elsevier Science Ltd. All rights reser ved.