ANODIC CHARACTERISTICS OF MASSIVE MANGANESE OXIDE ELECTRODE

The massive Mn oxides were synthesized and their anodic characteristics were investigated in aqueous solutions. The thermal treatment of the massive β-MnO2 at 480°C or above leads to the formation of α-Mn2O3, and the relatively high activity was observed for the anodic evolution of oxygen on the mixed oxide of ν-MnO2 and α-Mn2O3, compared with the pure oxide of β-MnO2. The active sites for the oxygen evolution reaction were regarded as the Mn(III) sites on the oxide surfaces. From the kinetic considerations for the oxygen and chlorine evolutions, it was suggested that the oxidation process of the electrode surface is a common rate-determining step in both reactions on the massive Mn oxide electrodes. © 1979.