Kinetic study of the cobalt electrodeposition onto glassy carbon electrode from ammonium sulfate solutions

Abstract

We carried out an electrochemical study of the cobalt electrodeposition onto glassy carbon electrode from an aqueous solution containing 10-2 M of CoSO4 + 1 M (NH4)2SO4 at natural pH 4.5. The potentiostatic study indicated a progressive 3D nucleation and growth during the deposition process. The average diffusion coefficient calculated for this system was 2.65 × 10-6 cm2 s-1 while the ΔG for the formation of stable nucleus was 6.50 × 10-20 J/nuclei. The scanning electron microscopy images indicated the formation of small and homogeneous nucleus onto GCE of approximately 300 nm.