Synergistic Chalcogenate and Fluorine Engineering on Metal Oxyhydroxides Breaks the OER Scaling Relationship

Abstract

Abstract The oxygen evolution reaction (OER), a bottleneck in electrochemical water splitting, is fundamentally limited by a scaling relationship between the binding energies of key intermediates (OH* and OOH*), imposing a minimum theoretical overpotential of 0.37 eV. Breaking this scaling relationship is crucial for enhancing OER activity, yet effective strategies remain scarce. We demonstrate that the introduction of high‐electronegativity fluorion on chalcogenate‐adsorbed nickel‐iron oxyhydroxide (NiFeOOH) significantly shortens hydrogen bonds between the chalcogenate and OER intermediates (*OH and *OOH). This shortening promotes proton transfer kinetics and lowers the theoretical overpotential to 0.27 eV. Guided by these calculations, the co‐adsorption of chalcogenate and fluorion on metal oxyhydroxide (NiFeSF‐R) catalyst is synthesized, and it achieves 1.0 A cm −2 at an ultralow overpotential of 304 mV in 1.0 M KOH, a substantial improvement of 106 and 182 mV compared to NiFeS‐R and NiFe, respectively. Notably, NiFeSF‐R exhibits exceptional stability, sustaining 1.0 A cm −2 for over 500 h with negligible degradation. In an anion exchange membrane water electrolyzer, the NiFeSF‐R anode stably achieves 1.0 A cm −2 at 1.73 V for 700 h at 50 °C. This work highlights the potential of local coordination environment tuning to break scaling relationships for high‐performance OER catalysts.