A quartz crystal microbalance study on oxidation of a cobalt electrode in an alkaline solution

The electrochemical behaviour of an electrodeposited cobalt was studied in an aqueous 1 M KOH solution at potentials below −700 mV vs. saturated calomel electrode. An Electrochemical Quartz Crystal Microbalance and a Rotating Ring Disk Electrode were used in the studies. Formation of a hardly reducible passive layer is responsible for time evolution of cyclic voltammetry curves. This layer can be reduced only by holding potential below −900 mV. The role of active Co dissolution in the evolution of CV profiles is of minor importance.