Mass‐Production of Mesoporous MnCo₂O₄ Spinels with Manganese(IV)‐ and Cobalt(II)‐Rich Surfaces for Superior Bifunctional Oxygen Electrocatalysis

Abstract

A mesoporous MnCo₂ O₄ electrode material is made for bifunctional oxygen electrocatalysis. The MnCo₂ O₄ exhibits both Co₃ O₄ -like activity for oxygen evolution reaction (OER) and Mn₂ O₃ -like performance for oxygen reduction reaction (ORR). The potential difference between the ORR and OER of MnCo₂ O₄ is as low as 0.83 V. By XANES and XPS investigation, the notable activity results from the preferred Mn^IV - and Co^II -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 MnCo₂ O₄ could be used in metal-air batteries and/or other energy devices.