The influence of electrolyte media on the deposition-dissolution behaviour of lead dioxide on glassy carbon electrode

Abstract

A comparative study of electrodeposition of PbO 2 from 1.0 M HClO 4, 1.0 HNO 3, 1.0 M acetic acid-1.0 M sodium acetate and 3.0 M KOH solutions containing 0.1 M Pb 2+ salts, on glassy carbon electrodes was carried out using cyclic voltammetric and chronoamperometric measurements. The oxidative formation of PbO 2 is found to follow 3-D nucleative growth with the same order of nucleation over voltage in these media involving pH variations between 0 and 14.5. Multisweep cyclic voltammetric studies indicate that the medium influence comes primarly through he chemical dissolution process following PbO 2 nuclei formation. In alkaline media, smaller nuclei undergo continuous chemical dissolution, leading to the growth of large-sized crystals. In acidic media, since chemical dissolution is less likely, a phase of different crystal sizes with a more compact structure evolves.