The mechanism of the reduction of PbO2 to PbSO4 in the anodic film on Pb was investigated using rotating ring-disk electrode (RRDE), and linear sweep voltammetry (LSV) at a stationary electrode. The anodic film studied was formed on Pb in sulfuric acid solution The experimental results of RRDE method show that the Pb-7wt.% Sb ring current during the reduction of the PbO2 in the anodic film on the Pb disk is due to the reduction of oxygen having previously diffused into the film as well as into the PbO2 particles in the film. No evidences of soluble intermediates have been detected. The effects of scan rate on LSV for the reduction of PbO2 in the anodic film on Pb conform to the reduction of a thin oxidized film. The mechanism of the mentioned reduction was suggested.

Key words: REACTION MECHANISM, REDUCTION, MEMBRANE ELECTRODES, ROTATION ELECTRODES, LEAD OXIDE, LEAD ACID STORAGE BATTERIES, LEAD SULFATE