Abstract

In this work, FeCoNi alloys embedded in carbon shell is synthesized by pyrolyzing ZIF-L with FeCl3 and NiCl2 as the additives. The study demonstrates that the catalyst ZIF-L-0.45Fe 0.15Ni-800, obtained with a Fe/Ni ion ratio of 3:1, exhibits superior oxygen reduction reaction (ORR) performance. In comparison to the direct pyrolysis of ZIF-L, the ZIF-L-0.45Fe0.15Ni-800 catalyst displays increased nitrogen content, enhanced degree of graphitization, larger specific surface area, and a hierarchical porous structure with FeCoNi alloys, all contributing to its improved ORR performance. The ZIF-L-0.45Fe0.15Ni-800 catalyst demonstrates comparable on-set potential and half-wave potential to commercial Pt/C (1.04 V and 0.86 V, respectively), with values of 0.98 V and 0.84 V, respectively. Following 7500 CV tests, the half-wave potential of ZIF-L-0.45Fe0.15Ni-800 only is decreased by 10 mV, outperforming commercial Pt/C which experiences a decrease of 31 mV. In addition, ZIF-L-0.45Fe0.15Ni-800 exhibits much higher methanol tolerance than commercial Pt/C. The maximum power density of the zinc air battery with ZIF-L-0.45Fe0.15Ni-800 as the cathode catalyst (120 mW cm−2) is equivalent to that with commercial Pt/C as the cathode catalyst (126 mW cm−2).