Ni3Fe nanoalloys embedded in N-doped carbon derived from dual-metal ZIF: Efficient bifunctional electrocatalyst for Zn-air battery

Developing non-noble oxygen electrocatalyst is of great importance in multiple energy conversion and storage technologies, for instance, metal-air battery , fuel cell and water electrolysis . Here, we report a bifunctional oxygen electrocatalyst derived from Ni–Fe dual-metal zeolitic imidazole frameworks, Ni 3 Fe nanoalloys embedded in N-doped carbon (Ni 3 Fe/N–C) containing carbon nanotube and porous carbon , which exhibits superior oxygen reduction and evolution reaction electrocatalytic performance. For oxygen reduction reaction , the onset potential and the half-wave potential of Ni 3 Fe/N–C are 0.92 V and 0.85 V, respectively, which are well consistent with those of commercial Pt/C. For oxygen evolution reaction , a low overpotential of 330 mV at 10 mA cm −2 is obtained for Ni 3 Fe/N–C, prominently better than that of commercial RuO 2 /C. Moreover, the oxygen reduction and evolution stability of Ni 3 Fe/N–C distinctly overmatches that of commercial Pt/C and RuO 2 /C. Benefiting from the favorable electrocatalytic activity and stability, the rechargeable Zn–air battery based on Ni 3 Fe/N–C exhibits smaller voltage gap (∼0.8 V) than the one based on commercial Pt/C and RuO 2 /C, and remarkable stability during 300-cycle discharge-charge test. The excellent performance can be attributed to the interaction between Ni 3 Fe nanoalloy and N-doped carbon, the unique nanostructure composed of carbon nanotube and porous carbons, and high graphitization degree.