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 cm 2 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.

Electrodeposition of Cobalt on the Carbon Surface from Cobalt Sulfate Solution by Cyclic and Linear Voltammetry in Developing Selective Electrodes for Phosphate Ion

“…This result was in-line with Kiruba & Jeyabharathi (2020) which the reduction of cobalt was electrodeposited by diffusion-controlled reduction reaction − 870 mV[12]. Meanwhile, other researchers also showed a potential in the − 800 mV region on the voltammogram for electrodeposition of cobalt with cobalt chloride material and ammonium chloride electrolyte solution which was carried out with a carbon ultramicroelectrode and a scan rate of 30 mV/s[13].Figure2is a voltammogram of cobalt electrodeposition on the surface of a carbon rod by linear sweep voltammetry. The results obtained indicate that there has been a reduction reaction of the cobalt.…”

“…[12]. Meanwhile, other researchers also showed a potential in the − 800 mV region on the voltammogram for electrodeposition of cobalt with cobalt chloride material and ammonium chloride electrolyte solution which was carried out with a carbon ultramicroelectrode and a scan rate of 30 mV/s [13].…”