Oxygen reduction catalysis of Mn–Co spinel oxides on a graphite electrode in alkaline solution

Abstract

Binary Mn–Co spinel oxides have been applied as catalysts for oxygen reduction on graphite electrodes in alkaline solution. Oxides with cation deficiencies were obtained by heating the homogeneous citrate and carbonate precursors with different atomic ratios of Mn/Co (0–1.5) at 400–600 °C in an O ₂ atmosphere. The oxygen reduction was studied by a rotating ring-disk electrode method, and these oxides loaded onto graphite showed catalytic activity for the direct four-electron reduction of oxygen. It is considered that cation deficiencies in the oxide catalysts contribute to the appearance of catalytic activity.