Further investigation of the equivalence of staircase and linear scan voltammograms. III-Averaged-current staircase voltammetry applied to electrochemical reactions involving adsorbed species

Abstract

Three voltammetric techniques are dealt with and compared in this work: first the linear scan voltammetry and next the staircase voltammetry used together with current sampling or current averaging on each step of the staircase signal. First, it can be stated that the averaged-current staircase voltammetry provides the same current data as a linear potential ramp, at the same potential scan rate, for any linear and time-invariant electrical/electrochemical dipole/system. Next, most electrochemical systems being nonlinear, the second aim is to show, through numerical simulation, that averaged-current staircase voltammograms well match linear scan voltammograms, taking the example of electrochemical reactions involving adsorbed species. Based on the relevant voltammetric models, theoretical investigation is carried out taking into account the Langmuir or Frumkin isotherm for adsorption, the reaction kinetics, the uncompensated resistance of the electrolyte, and the interfacial double-layer charging.