Synthesis of carbon microspheres loaded with manganese oxide as air cathode in alkaline media

Carbon microspheres with large surface have been synthesized from sucrose in H2SO4 solution by reflux-calcinations method. The catalyst of the manganese oxide loaded on carbon microspheres surface demonstrates significant catalytic activity for the oxygen reduction reaction in alkaline media and the mechanism of oxygen reduction is a 2e pathway. It shows an enhanced efficiency for electrochemical properties on active surface and apparent exchange current density 0.649 mA cm−2 (comes from the Tafel plots) for oxygen reduction reaction. This enhancement results from the large reaction area of the 7.32 wt.% manganese oxide loaded on carbon microspheres as well as the porous structures between this composite, which can significantly promote the efficient diffusion.