Abstract Hydrogen production via water electrolysis has garnered significant attention as a promising clean energy solution, but the limited availability of pure water presents a major barrier to large‐scale implementation. Efficiently utilizing seawater for the hydrogen evolution reaction (HER) remains challenging, primarily due to sluggish water dissociation kinetics and catalyst degradation in complex ionic environments. Here, Pt nanoclusters doping are integrated with phosphorus (P) vacancy engineering to modulate electron redistribution and optimize active sites. A Pt‐doped Ni 2 P catalyst with P vacancies (Pt@Ni 2 P v ) is synthesized on nickel foam, exhibiting exceptional HER activity in alkaline seawater electrolysis. Pt@Ni 2 P v achieves the industrially required current density of 1000 mA cm −2 at a low overpotential of 89 mV. Combined experimental and theoretical analyses reveal that P vacancies facilitate charge transfer to Pt nanoclusters, while Pt nanoclusters doping enhances hydrogen spillover to adjacent Ni sites. This dual modulation generates electron‐rich Pt sites that accelerate water dissociation to adsorbed hydrogen intermediates and promote hydrogen desorption, collectively boosting HER kinetics. These findings establish an effective strategy for enhancing seawater HER performance and offer new insights into the design of catalysts for scalable hydrogen energy technologies.
He et al. (Mon,) studied this question.