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.