Oxidation Kinetics of a Lead Electrode Covered with an Anodic Pb(II) Film in Sulfuric Acid Solution

Anodic polarization of lead electrodes covered with a preformed anodic Pb(II) film in the PbO potential region in 4.5 mol dm - 3 H 2 SO 4 solution was studied using linear sweep voltammetry and electrochemical impedance spectroscopy. The experimental results show that the polarization is mainly due to the slow charge transfer. The mechanism of the formation of the anodic PbO film is suggested as follows: (i) Pb + OH - → Pb(OH) a d + e - ; (ii) Pb(OH) a d + OH - → PbOOH + H + + e - (rds); (iii) PbOOH - → PbO + OH - .