FeNi co-doped electrocatalyst synthesized via binary ligand strategy as a bifunctional catalyst for Zn-air flow battery

Abstract Developing low-cost and excellent performance bifunctional catalysts for Oxygen Reduction Reaction (ORR) and Oxygen Evolution Reaction (OER) in rechargeable Zn-air batteries is of great significance. Recently, metal organic frameworks (MOFs)-derived electrocatalysts have been widely studied in ORR and OER due to their large specific surface area and tunable pore structure. However, it is still a challenge to prepare hierarchical porous structure catalysts via facile approach, which is desired in the device manner. Herein, we synthesized a MOF-derived FeNi co-doped catalyst (termed as B-FeNi-N/C-1000) using the binary ligand strategy with a large specific area and suitable hierarchical pore structures which efficiently improves mass transfer to boost the high device performance. As a result, the B-FeNi-N/C-1000 exhibits an outstanding ORR performance with a half potential of 0.9 V vs. RHE and a low potential of 1.62 V vs. RHE at 10 mA cm−2 in alkaline media, which exceeds FeNi catalyst (i.e., FeNi-N/C-1000) via single ligand method and commercial Pt/C + IrO2. Additionally, the B-FeNi-N/C-1000 presents a higher power density of 102 mW cm−2 and a long-term stability that only losses 2% after 95 h in the self-assembly Zn-air battery. Accordingly, this work can provide a facile method to synthesize efficient bifunctional catalyst for, but not limit to Zn-air flow batteries.