The Internal‐External Synergy of Self‐Reconstructed C/NiFeOOH/SeO ₄ ²⁻ for Efficient and Stable Seawater Electrolysis

ABSTRACT Renewable energy driven seawater electrolysis represents a promising approach for generating hydrogen. However, the development of seawater electrolysis is hindered by Cl–induced corrosion and competitive reaction. Transition metal selenides (TMSes), as promising anode catalysts, is impeded by reconstruction phenomena during the oxygen evolution reaction (OER), which leads to inefficient adsorption of OER intermediates and poor stability. Herein, an internal‐external synergy strategy of self‐reconstructed C/NiFeOOH/SeO ₄ ²⁻ was proposed to construct efficient and stable seawater electrolysis. The introduction of C accelerates the reconstruction process of C@FeNi ₂ Se ₄ to C/NiFeOOH/SeO ₄ ²⁻ . Internal C and external SeO ₄ ²⁻ jointly supply electrons to NiFeOOH to stabilize the valence state, forming a bidirectional electron‐stable structure. The C/NiFeOOH/SeO ₄ ²⁻ exhibits a low overpotential of 223 and 310 mV at 10 and 100 mA cm ⁻² in 1 M KOH + 0.5 M NaCl, along with exceptional stability 150 h at 400 mA cm ⁻² . Experimental and density functional theory calculations reveal that the SeO ₄ ²⁻ layer enhances the resistance to Cl ⁻ through electrostatic repulsion, and C increases the dissolution potential of NiFeOOH through strong electronic interaction with NiFeOOH, inhibiting the dissolution of metal sites. Meanwhile, SeO ₄ ²⁻ weakens the oxygen affinity of NiFeOOH and reduces the reaction energy barrier, while C ensures the rapid supply of electrons.