Substrate-Adaptive Sacrificial Corrosion Strategy Enables 700 mV Oxygen Evolution Window for Chloride-Resistant Seawater Electrolysis

Seawater electrolysis for hydrogen generation offers a sustainable solution to the energy crisis and freshwater scarcity, holding significant importance for the green hydrogen industry. The primary challenges in seawater electrolysis lie in the efficiency reduction and stability attenuation caused by the presence of Cl⁻ species in seawater. In this work, we propose a substrate-adaptive sacrificial corrosion strategy to universally synthesize highly active nickel-iron layered double hydroxide (NiFe-LDH) nanoarrays on diverse conductive substrates including carbon cloth and Ti mesh. The optimized electrode achieves an ultralow overpotential of 182 mV at 10 mA/cm², sustains 500 mA/cm² for 1000 h in 10 m KOH seawater, and retains performance after 3.5-year coastal storage. A quantitative protocol uncovers a 700 mV OER-only potential window (vs. 480 mV for IrO₂), attributed to oxygen vacancy-rich NiFeOOH active phase where Fe sites enhance OH* adsorption (0.19 eV overpotential) and Ni sites suppress Cl* interaction. This work provides a scalable synthesis platform and mechanistic insights for designing industrial seawater electrolyzers with extended durability and selectivity.