Robust Fe₃ Mo₃ C Supported IrMn Clusters as Highly Efficient Bifunctional Air Electrode for Metal-Air Battery

Catalysts at the air cathode for oxygen reduction and evolution reactions are central to the stability of rechargeable metal-air batteries, an issue that is gaining increasing interest in recent years. Herein, a highly durable and efficient carbide-based bifunctional catalyst consisting of iron-molybdenum carbide (Fe₃ Mo₃ C) and IrMn nanoalloys is demonstratred. This carbide is chemically stable in alkaline media and over the potential range of an air cathode. More importantly, Fe₃ Mo₃ C is very active for oxygen reduction reaction (ORR) in alkaline media. Fe₃ Mo₃ C supported IrMn as a bifunictional catalysts exhibits superior catalytic performance than the state of the art ORR catalyst (Pt/C) and the oxygen evolution reaction catalyst (Ir/C). IrMn/Fe₃ Mo₃ C enables Zn-air batteries to achieve long-term cycling performance over 200 h with high efficiency. The extraordinarily high performance of IrMn/Fe₃ Mo₃ C bifunictional catalyst provides a very promising alternative to the conventional Pt/C and Ir/C catalyst for an air cathode in alkaline electrolyte.