Electrocrystallization of Pd-Ni Alloys on Glassy Carbon Electrode

Using the Scharifker and Hills model and Heerman and Tarallo model, cyclic voltammetry and chronoamperometry were used to study the nucleation mechanism upon the electrodeposition of a Pd-Ni alloy from an electrolyte. The results show that the electrodeposition of the Pd-Ni alloy onto glassy carbon electrode consisted of nucleation and growth, and the nucleation process according to the Scharifker and Hills model follows three dimension-progressive nucleation, which is controlled by the diffusion of the electroactive species. By applying the Heerman and Tarallo model, the kinetic parameters associated with the crystal nucleation and growth processes were obtained. The nucleation rate constant and the density of active nucleation sites increased from 0.83 to 7.71 s-1 and from 2.77×104 to 7.09×104 cm-2, respectively, as the step potential was changed from -0.85 to -0.92 V (vs SCE).