HYDROGEN EVOLUTION IN ALKALINE WATER ON COBALT ELECTRODEPOSITS PREPARED FROM BATHS CONTAINING DIFFERENT ANIONS

Electrolytic cobalt deposits, as electrocatalytic materials, were prepared from baths containing chloride, sulphate or acetate. Electrodeposition was conducted at 200 A m-2 with or without oxygen bubbling at the cathode. The hydrogen evolution reaction (h.e.r.) on the cobalt electrodes was performed in 30 wt % KOH at 25, 40, 50, 60 and 70-degrees-C. Without oxygen bubbling during deposition, the cobalt electrodes prepared from the acetate bath gave superior performance for h.e.r. than electrodes deposited from the other baths. With oxygen bubbling, however, the lowest h.e.r. overpotential was obtained on the cobalt prepared from the chloride bath.