Cobalt electrodeposition onto HOPG electrode from ammonium sulfate solutions. Luis Humberto Mendoza-Huizar, Clara Hilda Rios-Reyes and Margarita Rivera. Quim. Nova, ISSN . 0100-4042. Vol. 33 No.5 2010.. DOI: http://dx.doi.org/10.1590/S0100-40422010000500019
It was carried out an electrochemical study of the cobalt electrodeposition onto HOPG electrode from an aqueous solution containing 10-2 M of CoSO4 + 1M (NH4)2SO4. Nucleation parameters such as nucleation rate, density of active nucleation sites, saturation nucleus and the rate constant of the proton reduction reaction (kPR) were determined from potentiostatic studies. An increase in kPR values with the decrease in the applied potential suggested a competition between H+ and Co2+ by the active sites on the surface. The ?G energy calculated for the formation of stable nucleus was 8.21x10-21 J/nuclei. The AFM study indicated the formation of small clusters of 50-400 nm in diameter and 2-120 nm in height.