Constructing Precise Coordination of Nickel Active Sites on Hierarchical Porous Carbon Framework for Superior Oxygen Reduction

Single‐atom catalysts (SACs) with specific coordination environment are expected to be efficient electrocatalysts for oxygen reduction reaction (ORR). Herein, NiN4C10 coordination site is constructed through encapsulating Ni2+ into the cavity of ZIF‐8 as a self‐sacrificing precursor and anchoring it on 3D N‐doped carbon frameworks. The NiN4C10 catalyst shows excellent ORR activity and stability, with a high half‐wave potential (0.938 V vs RHE), which is currently the best performances in Ni‐based SACs. The remarkable performance with high ORR activity in alkaline solution is attributed to the single‐atom nickel active sites with faster electron transport and suitable electronic structure. Moreover, the power density of zinc‐air battery assembled by NiN4C10 as cathode is 47.1% higher than that of the commercial Pt/C. This work not only provides a facile method to prepare extremely active Ni‐based SACs, but also studies the intrinsic mechanism toward the oxygen reduction reaction under alkaline condition.