A comparative analysis of square-wave voltammetry and multi-frequency electrochemical Faradaic spectroscopy for kinetic characterisation

Abstract

AbstractA rigorous comparison between square-wave voltammetry (SWV) and the recently proposed multi-frequency electrochemical Faradaic spectroscopy (MEFS) is presented for both a quasireversible electrode reaction of a dissolved redox couple at a planar macroscopic electrode and a catalytic regenerative electrode mechanism (EC′ reaction scheme) by means of numerical simulations. MEFS offers fast kinetic characterisation with a minimal set of experiments, as the system is interrogated with a range of SW frequencies in a single experiment. By changing the mid-potential Em, a critical parameter of MEFS, a broad range of standard rate constants for the heterogeneous interfacial electron transfer is accessible, ranging between 0.006 and 0.12 cm s−1. In the case of the EC′ mechanism, features of the current components in both SWV and MEFS reflect the involvement of the follow-up regenerative chemical reaction (i.e. C′ catalytic step). However, for the kinetic characterisation of the EC′ mechanism, the comparative analysis suggests that SWV should be the main operating technique.