Ga–O–Pt Electronic Bridges Bypass Single‐Site Constraints for pH‐Universal Hydrogen Evolution

ABSTRACT

Single‐site descriptors often fail to capture hydrogen evolution on heterometallic interfaces, where hydrogen adsorption, interfacial charge redistribution, and reaction kinetics are strongly modulated by potential and pH. Here, we engineer oxygen‐bridged Ga–O–Pt motifs, in which Ga–O moieties function as potential‐responsive charge‐buffering motifs that accommodate interfacial electron redistribution, while adjacent Pt ensembles mediate H ^* adsorption, migration, and recombination. Ga–O–Pt exhibits low overpotentials across 0.5

H ₂ SO ₄ , 1.0 KOH, and 1.0 PBS ( η ₁₀ = 7 mV in 0.5 H ₂ SO ₄ , 19 mV in 1.0 KOH, and 48 mV in 1.0 PBS). Combined isotope‐sensitive kinetics and operando X‐ray absorption spectroscopy support a Tafel‐recombination‐favored pathway in the acidic low‐overpotential region, enabled by rapid hydrogen redistribution rather than a proton‐coupled‐electron‐transfer‐limited step. In situ XAS further reveals potential‐dependent Pt/Ga electronic responses consistent with interfacial polarization across the Ga–O–Pt interface. Density functional theory supports electronically differentiated neighboring Pt sites, low‐barrier hydrogen migration, and a favorable Volmer–Tafel pathway on the representative Ga–O–Pt motif. Collectively, these results establish electronic‐bridge engineering as an effective strategy to transcend single‐site constraints and enable the rational design of pH‐universal HER catalysts under realistic electrochemical conditions.