Chloride-blocking MnOx/NiFe architectures enabling robust oxygen evolution in alkaline seawater

Seawater electrolysis offers a promising route to green hydrogen but is hindered by chloride-induced electrode corrosion and parasitic chlorine evolution. Herein, a chloride-blocking MnO x -coated NiFe layered-double-hydroxide nanosheet array on carbon cloth (MnO x /NiFe@CC) is developed. The porous NiFe scaffold provides abundant OER-active sites, while the surface-deposited MnO x coating limits Cl − access while maintaining rapid H 2 O/OH − transport. MnO x /NiFe@CC requires overpotentials of 255 mV in 1 M KOH + 0.6 M NaCl and 233 mV in 1 M KOH + saturated NaCl to reach 10 mA cm −2 , outperforming unprotected NiFe counterparts. Stable OER operation is maintained for 50 h under saturated NaCl-containing alkaline conditions. Molecular-dynamics simulations further suggest a Cl − -depleted interfacial region at the MnO x surface, providing a molecular-level explanation for suppressed chlorine-related side reactions and enhanced electrochemical stability. This work establishes an electrode-level strategy for chloride-resistant alkaline OER.