ELECTRODEPOSITION OF ZINC ON GLASSY CARBON FROM ZnCl2 AND ZnBr2 ELECTROLYTES.

Article abstract of DOI:10.1149/1.2120059

The initial stages of the electrocrystallization of zinc from 3M ZnCl//2 and 3M ZnBr//2 on glassy carbon has been investigated using cyclic voltammerty, the potential step method, and scanning electron microscopy. Particular care was taken to ensure electrolyte purity and to eliminate resistance effects in the measurements. The nucleation overvoltage in 3M ZnCl//2 was approximately equals 17 and approximately equals 12 m v in 3M MZnBr//2. In 3MZnCl//2, the current transients from the potential step measurements could be fitted to a simple mechanism is operative for 3M ZnBr//2 at low overvoltages. At higher overvoltages, the current transient is governed by mixed kinetic and diffusion control and cannot be fitted to a simple model. The lower nucleation overvoltage and the faster kinetics in 3M ZnBr//2 is correlated with lower stability constants for the zinc bromide complexes. Erroneous results are obtained when resistance effects are not accounted for.