Cyclic voltammetry in weakly supported media: The reduction of the cobaltocenium cation in acetonitrile - Comparison between theory and experiment

Experimental cyclic voltammetry at a hemispherical mercury microelectrode in acetonitrile solution, containing 3 mM cobaltocenium hexafluorophosphate and different concentrations of supporting electrolyte, is compared with theoretical simulations using the Nernst-Planck-Poisson system of equations, without the assumption of electroneutrality, and is found in to be in good agreement. Deviations from diffusion-only theory are analyzed in terms of migration and potential drop in the solution as a function of the concentration of supporting electrolyte. We are unaware of previous reports in which non-steady-state cyclic voltammetry without supporting electrolyte has been quantitatively and fully simulated, so this work opens up a new area for voltammetry.