Kinetics and mechanism of PbSO₄ electroformation on Pb electrodes in H₂SO₄ aqueous solutions

Abstract

The electrochemical processes related to the passivation of Pb in 5 M H₂SO₄ at 25°C, have been investigated combining a rotating ring-disk electrode, linear potential sweep voltammetry and potentiostatic pulse techniques complemented with scanning electron microscopic imaging. The kinetics of PbSO₄ anodic layer growth can be explained through the initial formation of a barrier layer acting as an ionic conductor, and the transference of Pb²⁺ cations from the substrate the conducting layer yielding Pb²⁺ ion in the solution. These ions further contribute to passivation through the precipitation of a PbSO₄ passivating layer.