Bismuth Doped PbO 2 Coatings: Morphology and Electrocatalytic Properties

Abstract

The influence of bismuth ions on kinetics of lead dioxide electrodeposition from methanesulfonate elec-trolytes and physico-chemical properties of obtained coatings were studied. Experimental results areconsistent with a mechanism previously proposed in the literature for lead dioxide electrodeposition.The presence of bismuth ions in the electrodeposition solution causes a decrease of rate constants oflead dioxide formation due to co-adsorption phenomena. Deposits from solutions containing bismuthions appear shiny dark grey, and show good adhesion to metal support. SEM images reveal a compactstructure with spindle-shaped submicron and nanosized crystals and X-ray diffractograms demonstratedthat incorporation of bismuth diminishes the size of crystal particles. Oxygen evolution was investigatedto test electrocatalytic activity. It is shown, that oxygen overpotential on modified electrodes is signifi-cantly higher than on non-modified PbO2-electrode, which depends on bismuth content in deposit andsegregation of bismuth that induces surface heterogeneity due to sites with different electroactivity forwater oxidation. © 2013 Elsevier Ltd.