POTENTIODYNAMIC AND CYCLIC VOLTAMMETRIC BEHAVIOR OF A LEAD ELECTRODE IN NAOH SOLUTION

The electrochemical behaviour of lead in NaOH solution was studied by potentiodynamic and cyclic voltammetric techniques in combination with X-ray diffraction analysis. The active dissolution of lead involves a small shoulder A1' followed by a peak A1 prior to a passive region. T he shoulder A1' is assigned to the electroformation of a Pb(OH)(2) fil m, whereas peak A1 is due to the formation of PbO. Beyond the passive region, the current density increases again, forming a small shoulder A2' and a peak A2 prior to the oxygen evolution potential. The shoulde r A2' and the peak A2 are correlated to the electrooxidation of PbO to Pb3O4 and PbO2, respectively. The intensity of the anodic peaks incre ases with increasing alkali concentration, temperature and scan rate. In cyclic voltammetry, the reverse scan shows two cathodic peaks C1 an d C2 which are correlated to the electroreduction of PbO and PbO2 resp ectively, to Pb.