Electrocatalysis of Anodic Oxygen‐Transfer Reactions: Chronoamperometric and Voltammetric Studies of the Nucleation and Electrodeposition of β‐Lead Dioxide at a Rotated Gold Disk Electrode in Acidic Media

Abstract

The electrodeposition of from solutions of Pb(II) at an Au rotated disk electrode (RDE) was studied as a function of applied potential, rotational velocity, and the concentrations of and Pb(II). A long induction period (i.e., ) is associated with high acidity, low concentration of Pb(II), and high rotational velocity. Following the induction period, the current rises to a steady‐state value which is significantly lower than the mass transport‐limited value for Pb(II). The steady‐state value of electrode current decreases as rotational velocity is increased, contrary to expectations for a mass transport‐controlled process at a RDE. The generation of a soluble intermediate species is proposed to account for these observations. Repeated cycles of deposition and stripping of at the Au RDE results in a decreasing induction period for subsequent deposition. This is concluded to result because a Pb(II) ad‐layer (possibly ) is formed which is stabilized by interaction with the Au substrate and is not dissolved following the negative potential scan to 0.3V. The original state of the clean Au surface is regenerated by cathodic evolution, chemical stripping with or , or by mechanical abrasion.