Efficient and durable seawater electrolysis with a V₂O₃-protected catalyst

The ocean, a vast hydrogen reservoir, holds potential for sustainable energy and water development. Developing high-performance electrocatalysts for hydrogen production under harsh seawater conditions is challenging. Here, we propose incorporating a protective V₂O₃ layer to modulate the microcatalytic environment and create in situ dual-active sites consisting of low-loaded Pt and Ni₃N. This catalyst demonstrates an ultralow overpotential of 80 mV at 500 mA cm^-2, a mass activity 30.86 times higher than Pt-C and maintains at least 500 hours in seawater. Moreover, the assembled anion exchange membrane water electrolyzers (AEMWE) demonstrate superior activity and durability even under demanding industrial conditions. In situ localized pH analysis elucidates the microcatalytic environmental regulation mechanism of the V₂O₃ layer. Its role as a Lewis acid layer enables the sequestration of excess OH^- ions, mitigate Cl^- corrosion, and alkaline earth salt precipitation. Our catalyst protection strategy by using V₂O₃ presents a promising and cost-effective approach for large-scale sustainable green hydrogen production.