Quasi-reversible EC reactions at spherical microelectrodes analysed by square-wave voltammetry

Fourier transform large amplitude alternating current voltammetry investigations of the split wave phenomenon in electrocatalytic mechanisms

Fourier transform large amplitude alternating current voltammetry (FTACV) studies are reported on an electrocatalytic (EC') mechanistic system which exhibits split wave behavior on both macro- and micro-size working electrodes. The electrochemical characteristics of the EC' mechanism were analysed using the fundamental to fourth harmonic components deduced by the Fourier transform algorithm. The effects of the sinusoidal frequencies of the applied potential, electrode geometry and substrate concentrations are investigated. The split wave phenomenon was observed and explored particularly.

A mechanistic study of the EC′ mechanism – the split wave in cyclic voltammetry and square wave voltammetry

In this paper, a detailed investigation of electrochemical reactions coupled with homogenous chemical steps using cyclic voltammetry (CV) and square wave voltammetry (SWV) was carried out to study the electrocatalytic (EC′) mechanism.

A new rapid and simple method to determine the kinetics of electrode reactions of biologically relevant compounds from the half-peak width of the square-wave voltammograms

A new method is introduced to determine the kinetic parameters of electron transfer reactions of biologically important compounds, based on the measurements of the half-peak width (DeltaE(p/2)) of the square-wave voltammograms. A simple surface (diffusionless) redox reaction, and a simple electrode reaction occurring from dissolved state are considered as model systems. In the region of quasireversible electron transfer, the half-peak widths of theoretical square-wave voltammograms are linear functions of the logarithm of the dimensionless kinetic parameter ln(K) that characterizes the rate of the electron transfer reaction. The dimensionless kinetic parameter K is defined as K=k(s)(fD)(-0.5) for the redox reaction taking place from dissolved state, whereas for the surface redox reaction K is defined as K=k(s)/f (k(s) is the standard rate constant of electron transfer, f is the SW frequency, and D is the diffusion coefficient). A set of linear regression equations for the dependences DeltaE(p/2)vs. ln(K) are derived, which can be used for rapid and precise determination of the charge-transfer kinetic parameters. The estimated values for the standard rate constants of various biologically relevant redox systems using this approach are in very good agreement with the experimental values determined by other square-wave voltammetric methods. The square-wave voltammetric half-peak width method can be used as a simple and reliable alternative to other voltammetric methods developed for the kinetic characterization of electron transfer rates.