Substrate-adaptive sacrificial corrosion strategy enables 700 mV oxygen evolution window for enhanced seawater electrolysis

Seawater electrolysis for hydrogen production offers a sustainable solution to the energy crisis and freshwater scarcity. The presence of chloride ions triggers competitive chlorine oxidation at the anode, which rivals the oxygen evolution reaction and leads to pronounced reductions in overall efficiency and long-term stability. This challenge underscores the urgent need for highly efficient, durable, and scalable anode materials to accelerate the transition of seawater electrolysis from laboratory research to industrial application. In this work, we introduce a substrate-adaptive sacrificial corrosion strategy that enables the universal growth of highly active corrosion products on a wide range of conductive substrates, notably including stainless steel. The optimized electrode achieves an overpotential of 182 mV at 10 mA/cm², and sustains 500 mA/cm² for 1000 h in 10 M KOH seawater. To fill the gap in describing anode selectivity, an oxygen evolution window is proposed and measured. The measured value of 700 mV, far exceeding the thermodynamic limit of 480 mV, provides compelling experimental evidence that kinetic regulation can break the thermodynamic framework. This work provides a scalable synthesis platform and mechanistic insights for designing industrial seawater electrolyzers with extended durability and selectivity.