Iron-Promoted Dynamic Reconstruction of Perovskite Fluorides Toward Oxygen Evolution Reaction

Rationally controlling the dynamic reconstruction of catalysts and elucidating catalytic reaction mechanisms are significant for the development of superior oxygen evolution reaction (OER) electrocatalysts. Herein, we construct a series of KCo_xFe_1-xF₃/NF perovskite fluoride precatalysts characterized by excellent reconstructability and high tunability via a facile solvothermal method. Relevant characterization results indicate that moderate Fe doping not only optimizes the crystal and electronic structure of perovskite fluoride precatalysts but also significantly promotes their structural reconstruction into Co/Fe oxyhydroxide active species. Electrochemical and theoretical analyses reveal that the catalysts primarily follow the adsorbate evolution mechanism during the OER. Furthermore, the introduction of Fe optimizes the adsorption of oxygen-containing intermediates at Co active sites, thereby lowering the energy barrier of the rate-determining step and enhancing the intrinsic OER catalytic activity. Among them, KCo_0.8Fe_0.2F₃/NF exhibits the optimal OER performance, with overpotentials of 230 and 267 mV at current densities of 10 and 100 mA cm^-2, respectively, and a stability exceeding 700 h. This work highlights the unique advantages of fluoride precursors in constructing high-performance OER catalysts and provides new insights into identifying the actual reaction pathway.