Characterization of different plasma-treated cobalt oxide catalysts for oxygen reduction reaction in alkaline media

Plasma-synthesized cobalt oxide supported on carbon has been analyzed for its use for electrocatalytic oxygen reduction reaction (ORR) in alkaline anion exchange membrane fuel cells (AEMFC). This work presents the ORR activity in 0.1 mol L−1 KOH and 0.1 mol L−1 K2CO3 at 25 °C. Cyclic voltammetry (CV) was used to determine the potentials at which the ORR occurs and to evaluate the stability of catalyst. Moreover, a rotating ring-disk electrode (RRDE) was used to investigate the activity of the catalysts and the formation of the by-product hydroperoxide anion (HO2−) as well as to identify the preferred pathway of the ORR. Calculated kinetic parameters for the ORR for the cobalt catalysts are shown in this work together with a comparison to a commercial platinum catalyst. However, the cobalt oxide produced more by-products which could lead to damage of the membrane in a fuel cell through a radical attack of the polymer backbone.