Study of homogeneous chemical reactions at spherical electrodes and microelectrodes in Additive Differential Pulse Voltammetry

Abstract

This is a theoretical work for the characterization of homogeneous chemical reactions coupled to a reversible electrode process and analyzed by Additive Differential Pulse Voltammetry at spherical electrodes or microelectrodes. Explicit analytical expressions are presented for the CE and EC mechanisms valid for spherical electrodes of any radius and fast chemical reactions. These enable us to easily and rapidly analyze the response of these mechanisms even under very strong kinetic conditions. The ADPV technique proves to be very useful in the identification of the reaction mechanism and the characterization of the coupled chemical reaction by means of the values of the peak currents and potentials and the crossing potential, which can be measured with good accuracy from several ADPV experiments with different pulse heights. Simple criteria are given for discrimination between different situations where the electrode process is coupled to a homogeneous chemical reaction and, what is more difficult, to distinguish between an EC mechanism and an irreversible charge transfer process. Moreover, direct procedures for quantitative determination of kinetic and thermodynamic information are established.