Implanting Hard Lewis‐Acid Sites Into NiFe Layered Double Hydroxide to Activate Lattice Oxygen and Inhibit Fe Dissolution for Efficient and Stable Oxygen Evolution

ABSTRACT The nickel‐iron layered double hydroxides (NiFe LDH) are promising catalysts for oxygen evolution reaction (OER), yet their practical application is constrained by unsatisfied activity and stability. Herein, a rational strategy based on hard‐soft‐acid‐base (HSAB) theory is proposed to facilitate the surface reconstruction of NiFe LDH into active metal oxyhydroxides by introducing hard Lewis‐acid (Zr ⁴⁺ ) sites. In situ characterizations and theoretical calculations elucidate that the incorporation of Zr ⁴⁺ can promote the adsorption of OH ⁻ and reduce the reconstruction barrier, thereby accelerating the surface reconstruction. The activated NiFeZr LDH (A‐NiFeZr LDH) with enhanced metal–oxygen covalency and more activated lattice oxygen demonstrates superb OER activity with ultralow overpotential (185 mV at 10 mA cm ⁻² ) and small Tafel slope (27.5 mV dec ⁻¹ ). Remarkably, owing to Zr‐mediated suppression of Fe dissolution, the anion exchange membrane water electrolyzer (AEMWE) based on A‐NiFeZr LDH exhibits impressive stability up to 1500 h at 1 A cm ⁻² in alkaline solution and 500 h at 1.5 A cm ⁻² in alkaline seawater at 60 °C. Furthermore, the AEMWE can also run stably for 3000 h in alkaline solution and 500 h in alkaline real seawater without decay under high‐frequency start‐stop fluctuations.