Vertically Grown Face‐To‐Face Nano‐Assembly of In(OH) 3 and NiFe‐LDH Enables Interfacial Charge Separation for Enhanced Alkaline and Seawater Electrolysis

Abstract NiFe‐layer double hydroxide (LDH) serves as a promising electrocatalyst toward alkaline oxygen evolution reaction (OER) and hydrogen evolution reaction (HER) owing to its superior activity among LDHs. However, its long‐term operational stability remains a critical issue due to structural degradation over prolonged electrolysis. Herein, a NiFe‐LDH/In(OH) 3 heterostructure is designed to simultaneously enhance both activity and durability. The face‐to‐face overlap between NiFe‐LDH and In(OH) 3 induces interfacial spatial separation, which mitigates structural collapse and increases the density of active sites. The strong in‐built interfacial electron transfer supported by experimental and theoretical studies shows a promotion of rapid charge transport, preventing charge accumulation at the interface to maintain optimum adsorption‐desorption of the reaction intermediates. Temperature‐dependent and in situ electrochemical impedance spectroscopy (EIS) analysis reveals the kinetic enhancement imparted by In(OH) 3 . The pH‐dependent study and density functional theory (DFT) calculation highlight the adsorbate evolution mechanism (AEM) pathway of OER with Fe as the active center. This strategy not only enhances the active site density for enhanced catalysis but also endows structural stability of over 200 hours of stable performance toward overall water electrolysis (OWE) with negligible degradation. Further, the heterostructure sustains similar performance in alkaline seawater for efficient hydrogen production from direct seawater.