Reaction and nucleation mechanisms of copper electrodeposition on disposable pencil graphite electrode

The reaction and nucleation mechanism of copper electrodeposition on disposable pencil graphite electrode (PGE) in acidic sulphate solution were investigated using cyclic voltammetry (CV) and chronoamperometry (CA) techniques, respectively. Electrochemical experiments were followed by morphological studies with scanning electron microscopy (SEM). The effect of some experimental parameters, namely copper concentration, pH, scan rate, background electrolyte, deposition potential, and conditioning surface of the electrode were described. At the surface of PGE, Cu2+ ions were reduced at −250 mV vs. SCE. It was found that electrodeposition of copper is affected by rough surface of PGE. The nucleation mechanisms were examined by fitting the experimental CA data into Scharifker–Hills nucleation models. The nuclei population densities were also determined by means of two common fitting models developed for three-dimensional nucleation and growth (Scharifker–Mostany and Mirkin–Nilov–Herrman–Tarallo). It was found that deposition potential and background electrolyte affect the distribution of the deposited copper. The morphology of the deposited copper is affected by background electrolyte.