Bromate-Anion Electroreduction at Rotating Disc Electrode under Steady-State Conditions: Comparison of Numerical and Analytical Solutions for Convective Diffusion Equations in Excess of Protons

Resumo

The article contains results of numerical analysis of convective-diffusion transport equations for the components of the bromate anion electrochemical reduction process at rotating disk electrode via the redox-mediator autocatalysis (EC″) mechanism. The problem is solved taking into account the difference in the diffusion coefficients of the components. It is assumed that the concentration of protons inside the solution is constant, including the diffusion layer, due to its high value compared to the concentration of bromate-anions. Comparison of the obtained results with the predictions of an approximate analytical study of the same system (Vorotyntsev, M.A., Antipov, A.E., Electrochim. Acta, 2017, vol. 246, p. 1217) confirms the adequacy of the developed analytical approach to the calculating of both the concentration profiles of the system’s components (with the exception of the case of very thick diffusion layer) and the current density for a wide range of external parameters: the solution composition, rate of the comproportionation reaction, the convection intensity (the electrode rotation velocity) and the passing current.