Reversal and cyclic chronopotentiometry with exponential current-time functions at spherical electrodes. Reversibility effects and experimental verification

摘要

General analytical solutions for the potential - time curves corresponding to a slow charge transfer reaction in reversal and cyclic chronopotentiometry with exponential current - time functions, I(t) = I(0)e(wt), have been deduced. For obtaining these equations, the superposition principle can be applied. Our results are valid for planar and spherical electrodes of any size. We have evaluated the effects of electrode sphericity and of the reversibility of the process on the potential - time curves. The analysis of the successive potential - time responses allows to obtain accurate values of the thermodynamic and kinetic parameters of the process under study as well as to detect any possible kinetic complication. The validity of the theoretical solutions has been experimentally tested with the iron(III) trioxalate complex in aqueous solutions.