Cl−-Driven Pathway Switching Enables Efficient Industrial-Current Seawater Oxidation on Dual-Atom Catalysts
Direct seawater electrolysis offers a promising route to green hydrogen production, circumventing freshwater scarcity. However, the presence of chloride ions (Cl−) poses severe challenges, including competing chlorine evolution reaction (CER) and corrosion of anode catalysts. Here, we report a dual-atom catalyst design, RuCr-Ni3P, where Ru atoms with strong chloride affinity and Cr atoms as Lewis acid centers are co-doped into a nickel phosphide matrix. This catalyst exhibits outstanding oxygen evolution reaction (OER) activity and selectivity in alkaline seawater, achieving stable operation for over 4000 hours at industrially relevant current densities. Mechanistic studies reveal that Cl− ions are selectively captured by Ru sites, forming a dynamic Ru–Cl coordination motif that electronically modulates adjacent Ni centers, promoting the formation of high-valent Ni>3+ species. This switches the OER pathway from the lattice oxygen mechanism (LOM) to the more efficient adsorbate evolution mechanism (AEM). Concurrently, Cr sites facilitate the formation of Cr–OH species, creating a localized alkaline microenvironment that further enhances OER kinetics. This dual-site synergistic mechanism transforms Cl− from a detrimental impurity into a beneficial chemical switch, concurrently enhancing both activity and stability. Our findings provide a paradigm shift in seawater electrolysis catalyst design, turning a longstanding challenge into an opportunity for efficient and durable hydrogen production.