Finite difference simulations of steady-state voltammetry at the wall-jet electrode. Effects of radial diffusion and working curves for common electrochemical mechanisms

Fully implicit steady-state finite difference simulations have been developed, which incorporate radial diffusion and either a one- or two-term convection approximation, and solved using an incomplete LU preconditioned multigrid-accelerated Krylov subspace method. The transport-limited current of a simple electron-transfer reaction was modeled to investigate the adequacy of the convection approximation. The current enhancement due to radial diffusion was then deduced as a sole function of the Peclet number. For the majority of experimental conditions, the effects of radial diffusion were found to be insignificant. Working curves and surfaces are presented for a number of common electrochemical mechanisms (E, ECE, EC2E, DISP1, DISP2, EC, EC2). These have been stored in electronic form and interfaced to mechanistic analysis software (freely available at http://physchem.ox.ac.uk:8000/wwwda)