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, Ni3Fe nanoalloys embedded in N-doped carbon (Ni3Fe/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 Ni3Fe/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 Ni3Fe/N-C, prominently better than that of commercial RuO2/C. Moreover, the oxygen reduction and evolution stability of Ni3Fe/N-C distinctly overmatches that of commercial Pt/C and RuO2/C. Benefiting from the favorable electrocatalytic activity and stability, the rechargeable Zn-air battery based on Ni3Fe/N-C exhibits smaller voltage gap (-0.8 V) than the one based on commercial Pt/C and RuO2/C, and remarkable stability during 300-cycle discharge-charge test. The excellent performance can be attributed to the interaction between Ni3Fe nanoalloy and N-doped carbon, the unique nanostructure composed of carbon nanotube and porous carbons, and high graphitization degree. (C) 2020 Elsevier Ltd. All rights reserved.

Automated summary

The Ni3Fe/N-C oxygen electrocatalyst shows excellent performance in oxygen reduction and evolution reactions, with stability surpassing that of commercial Pt/C and RuO2/C.