Study on kinetics of oxygen evolution on lead alloy anodes

A study was carried out on kinetics of oxygen evolution on lead alloy anodes in sulphuric acidic electrolyte. The influence of alloy elements Ca, Ag and Sn on the overpotential of oxygen evolution was investigated. All anodes had been subjected to a pre-polarisation before the measurement of potential-current curves for oxygen evolution. The overpotential of oxygen evolution was found to be decreased when the alloy anode contained Ca and Ag, whereas it remained unchanged when the alloy anode contained Sn. For oxygen evolution on lead alloy anodes the TAFEL equation was valid. The b vulue for Pb and Pb-Ca anodes was approx. 100, for Pb-Ag, Pb-Ag-Ca anodes it was approx. 140. The a value for Pb-Ca, Pb-Ag, Pb-Ag-Ca anodes decreased with the increase of Ca or/and Ag content. The a and b value was not influenced by Sn in the anodes.