Mathematical description of the diffusional “all-in-one” CrevE1CirrE2C’ mechanism under Butler-Volmer kinetics in Square-wave voltammetry

This work defines for the first time the reaction scheme, initial conditions, diffusion-reaction equations, electrode boundary conditions, and current expression for the diffusional CrevE1CirrE2C’ mechanism. All species are considered dissolved in solution; electron transfer occurs only at the electrode surface and is described by Butler-Volmer kinetics. This mathematical model provides a unified platform for studying complex diffusional electrochemical mechanisms involving chemical pre-equilibria, two electrode reactions, irreversible intermediate transformation, and catalytic regeneration. By adjusting selected kinetic constants, the model may reproduce simpler limiting mechanisms such as E, CE, EC, ECE, EC’, EE, and other more complex mechanisms evaluated out of the simples one.