Tuning the Ionic Liquid-Derived Doped Heteroatoms of Metallic Ferric–Nickel Fluoride Electrocatalyst for Enhanced Oxygen Evolution

The oxygen evolution reaction (OER) catalytic electrodes with enhanced activity and cost-effectiveness have been the key material to obtain clean hydrogen energy through water splitting on a large scale. Herein, the novel N, P-codoped carbon-encapsulated ferric–nickel fluoride (Fe–Ni–F@N, P–C) catalyst with abundant ionic liquid-derived doped heteroatoms is constructed via a facile annealing strategy. The optimized catalyst of Fe–Ni–F@N, P–C-300 yields an overpotential of 259 mV at a current density of 10 mA cm–2 in a 1.0 mol L–1 alkaline solution, affording a Tafel slope of 37 mV dec–1, as well as a robust stability for 12 h with only 0.73% degradation at 10 mA cm–2 and for 50 h with merely 2.80% degradation at a higher current density of 100 mA cm–2. In addition, the incorporation of heteroatoms (i.e., fluorine, nitrogen, and phosphorus) that originated from ionic liquids can obviously accelerate the formation of metal oxy/hydroxide and improve the electronic conductivity, resulting in the elevated *OH adsorption. Furthermore, the bimetallic synergistic effect also obviously increases the abundance of catalytic sites, leading to the enhanced OER property. Therefore, our work provides a viable approach for the design of high-performance fluoride-based OER catalysts with the assistance of ionic liquids.