Digital simulation of cyclic voltammetry in a two-electrode system and its application to the kinetics of bis(biphenyl) chromium(I) in N,N-dimethylformamide

Abstract

Abstract Standard apparent rate constants for the reduction of bis(biphenyl)chromium(I) tetraphenylborate on hanging mercury electrodes in N , N -dimethylformamide were determined from cyclic voltammetry in a two-electrode system. The kinetic data were extracted from multicyclic voltammograms with the help of digital simulation. The numerical simulation procedure accounts for the uncompensated potential drops due to the faradaic and double layer charging currents, allows the incorporation of constant or potential-dependent (experimental) double layer capacitance data and permits the selection of linear or spherical diffusion geometry. Simulations show the importance of the rigorous calculation of capacitive current for the precise determination of rate constants of fast electrode processes. Error limits in the k s app -values due to uncertainties in measured resistances and double layer capacitances can be assessed. The apparent standard rate constants for bis(biphenyl)chromium(I) couple obtained from this procedure proved that the increase in the reaction rate constants with the concentration of the supproting electrolyte is an electrochemical characteristic of this system and not due to an uncompensated resistance.