The role of silver in enhancing the electrochemical activity of lead and lead–silver alloy anodes

• Studied the role of silver in PbAg alloys in reducing the overpotential of the OER
• Ag2O2 was observed on Pb anodes in sulphuric acid containing silver ions.
• Evidence given for the presence of Ag2O2 on PbAg anodes in sulphuric acid
• The enhanced electrochemical activity of PbAg alloy anodes is attributed to Ag2O2.

The role of silver as an alloying additive to reduce the overpotential of the oxygen evolution reaction on lead anodes used in the electrowinning of zinc has not previously been established. This paper summarizes the results of a detailed study of the mechanism of the action of silver; both as an additive to the alloy and in solution. The presence of Ag2O2 in the oxide layer was confirmed on Pb electrodes anodised in sulphuric acid electrolytes containing silver ions. The enhanced electrochemical activity of PbAg alloy anodes over Pb is attributed to the presence of Ag2O2 in the corrosion layer.