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.