Preparation of anodes for oxygen evolution by electrodeposition of composite Pb and Co oxides

Abstract

The simultaneous anodic oxidation of Pb 2+ and Co 2+ in a sulphamate bath containing suspended Co 3O 4 (or NiCo 2O 4) particles has been studied as a method for preparing composite oxides in which the particles are dispersed in a matrix consisting of PbO 2 and hydrous Co oxides, CoO x with x<2. The (PbO 2+CoO x )+Co 3O 4 composites thus prepared are very rough and their Co concentration, expressed as X Co= N Co/( N Co+ N Pb), where N represents the number of atoms, approaches 0.5. As a result, they are more active catalysts in the oxygen evolution reaction than either PbO 2+CoO x or PbO 2+Co 3O 4 prepared in the past by our group. For samples prepared in the presence of particles, the potential required to evolve oxygen at a fixed current density varies roughly linearly with X Co, irrespective of the fact that Co is present as Co 3O 4 or CoO x .