Porous MCo₂O₄(M = Zn, Cu, Fe, Mn) as high efficient bi-functional catalysts for oxygen reduction and oxygen evolution...

High-efficiency bi-functional electrocatalysts with long-term stability are critical to the development of many kinds of fuel cells, because that the performance of battery is limited by the slow kinetics of oxygen reduction reaction (ORR) and oxygen evolution reaction (OER). In this work, porous MCo₂O₄(M = Zn, Cu, Fe, Mn) were prepared by hydrothermal method with NH₄F and urea as surfactants. FeCo₂O₄with porous structure has more oxygen defects and the larger specific surface area than other MCo₂O₄(M = Zn, Cu, Mn), and it not onlysupplies more active sites but also avails the transmission of electrolyte and O₂in the process of ORR and OER in 0.1 M KOH aqueous solution. Porous FeCo₂O₄electrode material produces less intermediate H₂O₂, and its ORR is mainly controlled by a 4e^-reaction path. Compared with commercial Pt/C, the prepared FeCo₂O₄has comparable ORR activity and excellent OER activity. At the same time, the stability of FeCo₂O₄to ORR is significantly higher than that of commercial Pt/C. The porous FeCo₂O₄was prepared by facile synthesis procedure could be a potential promising bi-functional catalyst due to its high electrocatalytic activities and long-term stability for both the ORR and OER.