Metal-organic framework-derived FeNi nanoparticles/3D N, S, F tri-doped porous carbon nanoflower for Zn-air batteries

Exploring highly active, cost-effective, and long-life non-precious metal-based catalysts for the oxygen reduction/evolution reaction (ORR/OER) is extremely important for renewable energy conversion devices. Herein, a facile approach is proposed to fabricate a FeNi nanoparticles decorated 3D N, S, F tri-doped porous carbon nanoflower/nanotubes electrocatalyst (FeNi@NSFC) by a self-assembly pyrolysis process. The ammonium sulfate not only acts as a N and S source but also facilitates the self-assembly of 2D ZnFeNi-ZIF nanosheets into 3D nanoflowers. Meanwhile, the potassium fluoride serves as a F source and regulates the crystal growth as well as pore structure. The 3D nanoflower/nanotube structure benefits the exposure of reactive species and mass/charge transport. The optimized FeNi@NSFC catalyst achieved outstanding bifunctional catalytic performance with an overpotential gap (0.655 V), which was lower than the Pt/C + RuO 2 catalyst (0.670 V). Theoretical findings also revealed that the introduction of N, S and F atoms could tailor the electronic structure of FeNi nanoparticles, thereby enhancing the catalytic activity for ORR. Therefore, the FeNi@NSFC-assembled Zinc-air batteries (ZABs) delivered a peak power density (156.2 mW cm −2 ), and long-term cycle durability (550 h), surpassing Pt/C + RuO 2 -assembled ZABs. This work demonstrates a promising avenue for developing MOF-derived catalysts with well-defined morphology and multi-atom doping.