Cyclic voltammetric wave-shapes for microdisk electrodes: Coupled effects of solution resistance, double-layer capacitance, and finite electrochemical kinetics

Cyclic voltammograms at microdisk electrodes that account for the effects of solution resistivity rho(Omega), double layer capacitance, C(dl), and electrochemical kinetics were simulated by using the explicit Hopscotch algorithm and a conformally mapped space-grid. The latter procedure, in particular, provides an efficient means of simulating voltammograms at slower potential scan rates where radial, rather than linear, diffusion predominates. Simulated voltammetric waveshapes as a function of scan rate are reported for systematic variations in rho(Omega), C(dl), and the standard electrochemical rate constant ks, both separately and together. The waveshape description utilizes both the anodic-cathodic potential peak separation, Delta E(p), and the halfwave potential for the forward scan in relation to the voltammograms where the influence of radial diffusion is sufficient to yield largely sigmoidal, rather than peaked, waveshapes.