Fe/Co Co‐Doping Engineering for Corrosion‐Resistant and Effective Seawater Electrolysis

Abstract Direct seawater electrolysis is a promising strategy for sustainable hydrogen production, yet it faces critical challenges in catalyst design, including scalability, chloride corrosion resistance, and cost efficiency. A one‐step interfacial redox strategy is reported to construct Fe/Co co‐doped Ru@Ni(OH) 2 electrodes (Ru@FeCo–Ni(OH) 2 ), enabling precise control of metal coordination environments while ensuring industrial‐scale manufacturability. This method enables the fabrication of 5000 cm 2 electrodes with no performance deviation, demonstrating compatibility with commercial electrolyzers. The Ru@FeCo‐Ni(OH) 2 electrodes exhibit remarkable durability (>3000 h) and achieve hydrogen production at $0.87 per kg using natural seawater from the South China Sea (unpurified, with KOH added), surpassing the U.S. Department of Energy's 2031 cost target of $1 per kg. Operando spectroscopy and DFT calculations reveal a synergistic co‐doping mechanism: 1) d‐band center downshifting (Δ E = 0.68 eV) optimizes hydrogen adsorption for superior hydrogen evolution reaction performance, while 2) accelerated surface reconstruction forms chloride‐resistant oxyhydroxide layers, improving oxygen evolution reaction efficiency. This work establishes a new paradigm in bifunctional catalyst design, providing mechanistic insights into active site evolution and a scalable pathway for cost‐effective green hydrogen production directly from seawater.