Electrode kinetics from a single square-wave voltammogram

Abstract

A novel methodological approach for processing electrochemical data measured under conditions of square-wave voltammetry (SWV) is proposed. The methodology takes advantage of the chronoamperometric characteristics of the electrochemical system observed in the course of the voltammetric experiment, which are commonly not considered in conventional SWV. The method requires processing of a single voltammogram only, measured under given set of the potential modulation parameters (i.e. SW frequency and height of the potential pulses). The core idea is to analyze the variation of the current with time, considering the last quarter time period of each potential pulse of the potential modulation, instead of measuring the single current value from the very end of the pulses. Hence, a single point current measurement is replaced with a multisampling current procedure, leading to a series of new SW voltammograms measured at different time increments of each potential pulse. The novel method is illustrated by the theoretical analysis of a quasireversible electrode reaction of a dissolved and surface confined redox couple, as well as a reversible electrode reaction preceded by a chemical equilibrium reaction (C<sub>r</sub>E<sub>r</sub> mechanism).