Journal of Electroanalytical Chemistry 303 (1991) 27-44

Theory of the effect of migration current exaltation taking into account dissociation-recombination reactions

Yu I. Kharkats and A. V. Sokirko

A.N. Frumkin Institute of Electrochemistry, Academy of Sciences of the USSR, Leninsky Prospect, 31, 11 7071, Moscow V-71 (USSR

(Received 14 May 1990; in revised form 11 October 1990)


The influence of the recombination process of OH- and H+ ions on the migration current exaltation effect, which has been observed during the parallel reduction of cations and the neutral substance [1,2], is considered here. It is shown that qualitatively different types of behavior of the system studied are possible depending on the ratio of concentrations of discharging cations and H+ ions in the solution. It is found that under certain conditions in acid solutions an unusual limiting diffusion-migration current of cation discharge may be observed due to the falling off to zero of the cation concentration within the diffusion layer. For neutral solutions, approximate analytical solutions and numerical solutions of the corresponding system of electrodiffusion equations are obtained. It is shown that for real values of the water dissociation-recombination equilibrium constant, due account of the recombination process leads to a relatively small correction in the theory of the migration current exaltation effect developed in refs.3-6.