Tailoring atomic-level electron redistribution of metal phosphides/oxides heterostructural catalyst for efficient alkaline freshwater/seawater hydrogen evolution

Developing efficient and durable electrocatalysts for the alkaline hydrogen evolution reaction (HER) is crucial for sustainable hydrogen production. Although heterointerfaces between transition metal phosphides (TMPs) and metal (hydro)oxides (MOs) offer promise, their performance is fundamentally limited by inherent bottlenecks: strong hydroxyl (OH*) binding poisons the water-dissociation sites, while suboptimal hydrogen (H) adsorption persists on the TMP regions. Herein, we report a universal dual-phase boron doping strategy to simultaneously modulate the electronic structures of both components in a model Ni₂P/V₂O₃ heterostructure. Experimental and theoretical analyses reveal that boron doping induces localized electron enrichment at V and P sites, achieving three synergistic effects: weakened OH* binding on V sites to prevent poisoning, near-ideal H* adsorption strength on P sites, and enhanced interfacial electric fields that accelerate water dissociation. The resulting Ni₂B_xP_1−x/V₂B_yO_3−y catalyst requires ultralow overpotentials of 16 mV (alkaline freshwater) and 17 mV (alkaline seawater) at 10 mA cm⁻², with exceptional durability over 100 h at 1000 mA cm⁻² in corrosive seawater. The universality of this strategy is demonstrated across diverse TMP/MO systems, establishing a generalizable paradigm for designing high-performance, industry-relevant electrocatalysts.