Exploring the determination of the standard rate constant in electrochemical metal deposition: theory and experiment

Abstract

A detailed investigation of the electrochemical metal deposition was carried out using both simulation and experimental cyclic voltammetry (CV). Kinetic curves were developed to relate peak-to-peak potential separation (ΔEp) to the cathodic charge transfer coefficient (α) and the standard rate constant (k0). From these curves, interpolation equations were derived to estimate k0, taking into account the effect of the transfer coefficients sum (α + β), whether equals to or different from 1. The validity of the equations was confirmed through the reduction of silver, copper and rhenium ions in various electrolytes, yielding k0 values of 14.51 × 10−6 m s−1 for Ag+/Ag, 5.98 × 10−7 m s−1 for Cu+/Cu and 10.59 × 10−8 m s−1 for Re6+/Re. According to the Matsuda–Ayabe criteria for assessing electron-transfer reversibility, the Ag+/Ag and Cu+/Cu redox couples are regarded as quasi-reversible, while the Re6+/Re couple is classified as irreversible. The simulated CVs showed strong agreement with experimental results.