Improved performance of cobalt-based spinel by the simple solvothermal method as electrocatalyst for oxygen reduction reaction in alkaline solution

The performance of the cobalt-based spinel electrocatalysts (MCo 2 X 4 ) is improved for oxygen reduction reaction (ORR) by simply optimizing solvothermal conditions via the orthogonal experiment L 18 (2 × 3 7 ). Five conditions are investigated, and the order of significant factors for ORR efficiency is metal component > solvothermal temperature > calcining temperature > precipitant > solvent component. Mn, Ni, or S is considered as the factor of metal component or precipitant respectively and is introduced into the Co 3 O 4 to find the best MCo 2 X 4 for ORR. But, the pure Co 3 O 4 exhibits the best performance among these cobalt-based catalysts. The optimized product, 9.6 wt.% Co 3 O 4 supported on carbon (Co 3 O 4 /C), can reach 90 % of the 20 wt.% Pt/C in term of the limited diffusion current exhibiting the close efficiency of Co 3 O 4 /C to Pt/C. Methanol-poisoning tests performed by chronoamperometry show the Co 3 O 4 /C remained 95 % current after 6 h, exhibiting superior methanol resistance and long-time stability.