Fluorine-doped induced crystal/amorphous heterojunctions in CoFe-based nanolayers for high-performance alkaline
Man-Man Li1, Li Yuan1, Kai-Xin Gan1
1State Key Laboratory of Heavy Oil Processing, College of Chemistry and Chemical Engineering, China University of Petroleum (East China), Qingdao 266580, PR China.
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Unlocking the full potential of CoFe-based oxygen evolution reaction (OER) electrocatalysts is currently impeded by the dual challenges of sluggish intrinsic kinetics and thermodynamic instability caused by severe iron leaching. Herein, we report a synergistic strategy combining molten salt synthesis and fluoride calcination to engineer F-doped CoFe-based nanosheets (Fe,F-CoNH). The optimized Fe,F-CoNH catalyst demonstrates superior OER performance, requiring an overpotential of only 241 mV to reach 100 mA cm-2. Notably, it exhibits exceptional stability for 100 h at an industrial-level current density of 1 A cm-2 in both three-electrode configurations and anion exchange membrane water electrolyzers (AEMWEs). Mechanistic investigations reveal that F-doping creates defect-rich crystalline-amorphous interfaces and modulates the electronic structure of Co/Fe sites via strong electronic interactions. This dual effect optimizes intermediate adsorption energies while the robust metal-fluoride (M-F) bonds significantly suppress Fe leaching. Consequently, this work presents a promising molten salt-fluoride strategy for constructing robust, high-performance OER electrocatalysts for practical applications.
