Electrochemical studies of Zn underpotential/overpotential deposition on a nickel electrode from non-cyanide alkaline solution containing glycine

In this work we present an electrochemical study of the underpotential deposition (UPD) and overpotential deposition (OPD) of zinc onto nickel electrode (NE) from a non-cyanide alkaline solution containing glycine. The studied parameters were zinc concentration, glycine concentration and scanning rate. The analysis of the experimental data clearly showed the presence of UPD and OPD processes that started at −0.8 V vs. SCE and −1.4 V vs. SCE, respectively. The voltammetric studies also indicate diffusion control of the zinc UPD and OPD processes onto the NE. From the potentiostatic transients we found instantaneous nucleation (2D) mechanisms, which agree to that observed in the AFM study. In order to compare the effect of zinc/glycine concentration, we calculate thermodynamic parameters for the OPD process.