Faculty of Medical Sciences, Goce Delcev University, Stip, Macedonia
A peculiar feature of catalytic wave (or catalytic peak), appearing in voltammograms of a surface regenerative electrode mechanism (surface EC’ mechanism), in which an irreversible reduction of substrate “Y” to its final form “Z” is mediated by an adsorbed redox couple Ox/Red, is studied theoretically under conditions of square-wave voltammetry. This phenomenon, also known under the term ‘split-wave’ in cyclic voltammetry, appears when the rate of electron transfer step at the electrode surface is fast and comparable to the rate of chemical regenerative reaction. The effect of the kinetics of chemical regenerative step to the features of simulated square-wave voltammograms is studied for systems featuring quasi reversible and fast electron transfer steps. We present a relevant set of theoretical data, while we focus on conditions under which the two peaks in square-wave voltammetry can be resolved. An experimental observation of this phenomenon, which occurs in a very limited kinetic region, provides a basis to propose a simple methodology for assessing the rate constant of catalytic reaction.