Marcus–Hush–Chidsey theory of electron transfer to and from species bound at a non-uniform electrode surface: Theory and experiment

Two simple models of electrode surface inhomogeneity based on Marcus–Hush theory are considered; a distribution in formal potentials and a distribution in electron tunnelling distances. Cyclic voltammetry simulated using these models is compared with that simulated using Marcus–Hush theory for a flat, uniform and homogeneous electrode surface, with the two models of surface inhomogeneity yielding broadened peaks with decreased peak-currents. An edge-plane pyrolytic graphite electrode is covalently modified with ferrocene via ‘click’ chemistry and the resulting voltammetry compared with each of the three previously considered models. The distribution of formal potentials is seen to fit the experimental data most closely.