The influence of deposition conditions and dopant ions on the structure, activity, and stability of lead dioxide anode coatings

beta-lead dioxide layers have been electroplated onto gold from nitric acid solutions and the influence of lead (II) concentration, dopant ions in the bath, pH, temperature, current density, and deposition time on the characteristics of the deposits and their properties as anode materials for synthesis and effluent treatment have been examined. The most adhesive, abrasion resistant and chemically stable deposits were prepared in 0.5 M Pb(NO3)(2)/1 M HNO3 at a temperature of 333 K and using a current density of 5 mA cm(-2); these deposits had a morphology consisting of angular crystallites but they were rather inactive as anode materials. In many other conditions, deposits were made up of overlapping hemispherical centers. Such layers were significantly less stable in open-circuit conditions and were both dissolved slowly in acids and reduced by dimethyl sulfoxide in acidic solutions. On the other hand, they supported the anodic oxidation of organic molecules. Bismuth (III) was a preferred dopant ions; it led to a preference for deposits consisting of hemispherical centers even in conditions where angular crystallites were formed in the absence of Bi (III). The Bi (III) doped coatings represent the best compromise between stability and the ability to support anodic oxidations