AN ELECTROCHEMICAL STUDY OF THE COBALT ELECTRODEPOSITION ONTO A CARBON FIBER ULTRAMICROELECTRODE

Abstract

A kinetic study of the cobalt electrodeposition onto a carbon fiber ultramicroelectrode of 11 µm of diameter was conducted in overpotential conditions from an aqueous solution containing 0.01 M CoCl2 + 0.1 M NH4Cl. From the voltamperometric and chronoamperometric studies, it was found that the value of the diffusion coefficient is 1.2x10-5 cm2 s-1. The analysis of the current density transients suggests that cobalt electrodeposition onto a carbon fiber electrode follows an instantaneous nucleation process controlled by spherical diffusion mass transport. Also, the number of active nucleation sites increases as the applied potential decreases.