On the theory of cyclic voltammetry for multiple nucleation and growth: Scan rate influence

The regularities of the formation and dissolution of independent new-phase nuclei on an indifferent electrode during a cyclic potential sweep were analyzed. Equations for cyclic voltammograms and nuclei sizes were derived for cases of simultaneous or progressive nucleation with diffusion-controlled growth or kinetically (charge transfer) controlled growth. Results of numerical simulation obtained at various values of the scan rate were presented. It was found that current extrema can be proportional to the scan rate raised to the power of -1/2, -3/2, -2, -3, depending on the nucleation type and the limiting growth stage. Criteria for identification of phase formation mechanism were verified by analyzing the experimental cyclic voltammograms for the electrodeposition/electrodissolution of silver nuclei on iridium in the KNO3-NaNO3-AgNO3 melt.

Automated summary

This study analyzed the regularities of formation and dissolution of independent new-phase nuclei on an indifferent electrode during a cyclic potential sweep, deriving equations for cyclic voltammograms and nuclei sizes for cases of simultaneous or progressive nucleation, diffusion-controlled growth, or kinetically controlled growth. Numerical simulation results showed that current extrema can be proportional to the scan rate raised to different powers, depending on the nucleation type and limiting growth stage. The experimental cyclic voltammograms for the electrodeposition/electrodissolution of silver nuclei on iridium in a KNO3-NaNO3-AgNO3 melt verified criteria for identification of phase formation mechanism.