Kinetic and Morphological Study of Zn Electrodeposition onto HOPG from Alkaline Aqueous Solutions

In this study, we conducted an electrochemical analysis of the electrodeposition of Zn onto a highly oriented pyrolytic graphite (HOPG) electrode from an aqueous solution containing 0.01 M ZnSO and 1 M (NH)SO at pH 8 and 25 C.Voltammetric studies indicate that, under our experimental conditions, Zn electrodeposition is an irreversible diffusion-controlled process.Potentiostatic study was used to determine kinetic parameters such as the number of active nucleation sites (N), and the nucleation rate (A), which exhibited a dependence on the applied potential.The morphology of the Zn deposits was examined using scanning electron microscopy (SEM).The results show that electrodeposition at lower potentials leads to rougher surfaces, likely due to increased hydrogen evolution, which interferes with the uniformity of Zn growth.In contrast, at more positive potentials, Zn deposits appeared more homogeneous, suggesting a more controlled nucleation and growth process with reduced proton reduction process.