Influence of bismuth on hydrogen and oxygen evolution on lead-calcium-tin-aluminium grid alloys

Hydrogen and oxygen evolution on lead-calcium-tin-aluminium alloys with different bismuth additions, in the range 0.002 to 0.073 wt.%, in sulfuric acid solutions at room temperature have been investigated. Hydrogen evolution rates are measured by linear sweep voltammetry. Kinetic parameters of the hydrogen evolution reaction on electrodes show that the incorporation of bismuth in the alloys decreases the hydrogen overpotential and increases the hydrogen evolution rate. Oxygen evolution rates are measured by a step-potentiostatic method, together with gas collection. The results show that oxygen evolution rates are enhanced by the bismuth additions and also influenced by the quantity of lead dioxide on the electrode surface. The effect of structure of the alloy surface on hydrogen evolution rate is also discussed.