Structure-Dependent Interfacial Electrostatic Regulation Enables Platinum-Efficient Hydrogen Evolution in Pt-Ag...

The electrocatalytic hydrogen evolution reaction (HER) is central to sustainable hydrogen production. Platinum (Pt) is widely regarded as the benchmark HER catalyst due to its near-optimal catalytic properties. However, its scarcity and high cost severely constrain scalable deployment. Here, we demonstrate that structure-induced interfacial electrostatic regulation enables platinum-efficient HER while minimizing Pt loading. A one-dimensional nanoensemble composed of Ag nanowires decorated with Pt nanoparticles integrates electronic hybridization, facet-dependent charge accumulation, and directional charge transport to boost HER. The solid PtAgNW (S-PtAgNW) nanoarchitecture containing only 15 wt.% Pt achieves the lowest overpotential of 290 mV at an ECSA-normalized current density of 500 mA cm^-2 with a Tafel slope of 42 mV dec^-1. It delivers a Pt-normalized hydrogen production rate of ∼50 mol g_Pt ^-1 h^-1 at ∼93% Faradaic efficiency, representing a >6-fold enhancement over its hollow counterpart despite the latter possessing higher Pt loading and similar interfacial chemistry. Mechanistic analysis reveals that Ag-to-Pt electronic coupling and facet redistribution toward Ag(111) enhance electron accumulation under bias, strengthening the interfacial electrostatic environment that governs proton-electron coupling. These findings establish interfacial electrostatic regulation, rather than Pt loading or intrinsic catalyst chemistry alone, as an important determinant of efficient HER.