Mass-production of mesoporous MnCo₂O₄ spinels with manganese(IV)- and cobalt(II)-rich surfaces for superior bifunctional oxygen electrocatalysis

Abstract A mesoporous MnCo₂O₄ electrode material is made for bifunctional oxygen electrocatalysis. The MnCo₂O₄ exhibits both Co₃O₄-like activity for oxygen evolution reaction (OER) and Mn₂O₃-like performance for oxygen reduction reaction (ORR). The potential difference between the ORR and OER of MnCo₂O₄ is as low as 0.83 V. By XANES and XPS investigation, the notable activity results from the preferred MnIV- and CoII-rich surface. The electrode material can be obtained on large-scale with the precise chemical control of the components at relatively low temperature. The surface state engineering may open a new avenue to optimize the electrocatalysis performance of electrode materials. The prominent bifunctional activity shows that MnCo₂O₄ could be used in metal–air batteries and/or other energy devices