Interfacial water modulation through Lewis acid-base pairs for efficient hydrogen evolution in seawater

To address cathode deactivation caused by Cl^- corrosion and Ca²⁺/Mg²⁺ hydroxide precipitation in seawater electrolysis, this study incorporate high valent Nb into Ni₅P₄ (Nb-Ni₅P₄) catalyst through Lewis acid-base synergistic regulation of interfacial water structure. High valent Nb (Lewis acid) and Ni (Lewis base) form dual active sites, among which Nb selectively adsorbs OH^- and Ni adsorbs H⁺ of water molecule, thus weakening hydrogen bond networks and accelerating water dissociation. In-situ characterization and density functional theory (DFT) calculations confirm Nb doping enhances OH^- affinity, suppress Cl^- adsorption, and shortens interfacial water hydrogen bond lifetime, and Ni sites optimize ΔG_H⁎ to balance H⁺ adsorption/desorption, synergistically enhancing hydrogen evolution reaction (HER) kinetics in seawater. Bubble dynamics visualization reveals the catalyst produces smaller, faster-desorbing bubbles that suppress Ca²⁺/Mg²⁺ hydroxide precipitation. Benefiting from above, Nb-Ni₅P₄ achieves 1000 mA cm^-2 at 333 mV in alkaline seawater and 500 mA cm^-2 at 459 mV in natural seawater, with stable operation exceeding 500 h in anion exchange membrane (AEM). This study proposes a Lewis acid-base dual-site and interfacial fluid dynamics regulation mechanism, establishing a new design paradigm for efficient, corrosion-resistant, and scale-resistant seawater hydrogen production catalysts in complex electrolyte environments.