Underpotential – Overpotential Phase Transformation Phenomena in Copper Deposition Processes on Glassy Carbon

Abstract

ABSTRACTThe initial stages of copper electrodeposition on glassy carbon were studied from a solution of 1 M CuSO4 in 0.5 M H2SO4 by the methods of potentiostatic current transients and pulse experiments. The experimental data were analyzed according to the theory of potentiostatic current transients for three-dimensional multiple nucleation with diffusion controlled growth. The theory was found to be in good agreement with experimental data for instantaneous copper nucleation in the cathodic overpotential range η = −0.18 – −0.40 V. It is shown that in case of progressive nucleation at η ≤ −0.16 V, this theory can be used only for trend analysis of copper nucleation process parameters. An important influence of the initial state of glassy carbon surface on the nucleation rate was found determined by the underpotential. It is shown that the dependence of nucleation rate on the underpotential is inadequate and is determined by cathodic overpotential.