Facile synthesis of well dispersed spinel cobalt manganese oxides microsphere as efficient bi-functional electrocatalysts for oxygen reduction reaction and oxygen evolution reaction

Developing catalysts with high bi-functional electrocatalytic activity for oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) is essential for the fuel cells and metal-air batteries because of the sluggish kinetics of oxygen electrochemical reaction. Herein, we prepared a porous and well dispersed spinel MnCo2O4 (MCO) catalyst through a facile solvothermal method followed by a calcination process. CH3COONH4 used in solvothermal process played an important role in control of the size and morphology of MCO. The as-prepared MCO submicrospheres feature a porous structure and a high specific surface area. Tested by the rotating ring disk electrode (RRDE) technique, the sample MCO-10 and MCO-5 shows best catalytic towards ORR and OER, respectively. In particular, MCO-10 exhibits a high diffusion limiting current density (5 mA cm−2) and a better stability comparable to commercial Pt/C (20 wt% Pt on carbon) catalyst.