Metal–Organic-Framework-Derived Trimetallic Nitrogen-Doped Nanoflowers as Bifunctional Oxygen Electrocatalyst for Rechargeable Zn–Air Battery

Low-cost, highly active and durable bifunctional oxygen electrocatalysts are critical for the commercial development of rechargeable zinc–air batteries (ZABs). Here, we report a trimetallic Fe/Co/Zn codoped nitrogen carbon catalyst (Fe 1 -CoZnNC-800) derived from a bud-like zeolitic imidazolate framework (ZIF-12@ZIF-11) obtained via the incorporation of Fe 2+ into the parent MOF. Pyrolysis at 800°C transforms the precursor into an open, flower-like carbon architecture that exposes abundant M–N x (M = Fe, Co) active sites while retaining a hierarchical meso-/macropore network (Brunauer–Emmett–Teller, BET ≈320 m 2 g − 1 ). In 0.1 M KOH, Fe 1 –CoZnNC-800 delivers a half-wave potential of 0.81 V for the oxygen reduction reaction (ORR) and an oxygen evolution reaction (OER) overpotential of 360 mV at 10 mA cm −2 , outperforming most nonprecious benchmarks with robust stability and good methanol tolerance. When integrated into a ZAB air cathode, Fe 1 –CoZnNC-800 affords a peak power density of 394 mW cm −2 and sustains stable charge/discharge cycling for 275 h at 10 mA cm −2 without obvious voltage fade, demonstrating its potential as a platinum-free bifunctional cathode for next-generation metal–air batteries.