A comparison of the Butler–Volmer and asymmetric Marcus–Hush models of electrode kinetics at the channel electrode

We report a theoretical study of steady-state voltammetry at the channel electrode comparing the Butler–Volmer and Marcus–Hush (both symmetric and asymmetric) models of electrode kinetics. The latter model is shown, for small values of both reorganisation energy and standard rate constant, to exhibit a kinetically-limited steady-state current which is smaller than the mass-transport limiting current given by the Levich equation. However, the combination of parameters required to observe this kinetically-limited current is unlikely to occur in a ‘real’ system. We conclude that the Butler–Volmer model is sufficient to accurately model voltammetry under these conditions.