Comparison of the reduction behaviour of anodic PbO2 films on Pb-As and Pb-Bi alloys in sulfuric acid

Abstract

The reduction behaviour of the anodic PbO2 films on Pb-3at% As and Pb-3at% Bi has been investigated using in situ photocurrent spectroscopy, impedance methods, chronoamperometry and linear sweep voltammetry. The experimental results show that most of the PbO2 in the film can be converted to PbSO4 in about 2s at 1.0V (vs Hg/Hg2SO4). Alloying with both As and Bi slightly retards this reduction process. The remaining PbO2 can only be reduced at a lower potential, (e.g., 0.60 V vs Hg/Hg2SO4) to t-PbO. Alloying with As slows down this second reduction process, while alloying with Bi accelerates it markedly.