Influence of diffusion coefficient ratio [formula omitted] on potential-step chronoamperometric and linear voltammetric current at stationary planar electrodes in the case of a pseudo-first-order EC catalytic reaction scheme

Abstract

Equations for limiting potential-step chronoamperometric and linear voltammetric currents at stationary planar electrodes for the case D O ≠ D R have been derived for a pseudo-first-order EC catalytic reaction scheme with reversible electrochemical and irreversible chemical reactions. The limiting potential-step chronoamperometric and linear voltammetric current curves have been calculated for various values of the diffusion coefficient ratio D O D R . The influence of the ratio D O D R on the theoretical currents has been examined. Theoretical possibilities to deduce both the kinetic parameter of the homogeneous chemical catalytic reaction and the ratio D O D R from the experimental limiting potential-step current—time curves or linear voltammetric current—potential curves have been discussed. A simple diagnostic criterion for linear voltammetry allowing evaluation of the chemical reaction rate constant and the ratio D O D R , has been proposed.