Theory of cyclic voltammetry at the mercury film electrode: Reversible case with substrate present initially in aqueous solution

Abstract

The theory of cyclic voltammetry has been extended to include the case of a reversible process proceeding at the mercury film electrode. The results of the solution of the diffusion equations were presented in the form of a simple equation coupled with a set of current function values. Such a presentation allows the entire cyclic curve to be drawn, when the difference between the switching potential and the peak potential is constant. Additionally, simple theoretical relationships were given for the ratio i p c/ i p a, for the differences E p a− E p c, and E p/2 c− E p c, and for the width of the anodic peak at half height. Experimental results obtained for the Pb(II)−Pb(Hg) couple at the silver-based and glassy carbon-based mercury film electrodes agreed excellently with the theory. On the other hand the results obtained at the platinum-based mercury film electrode deviated markedly from the theoretical predictions.