Structure‐Dependent Interfacial Electrostatic Regulation Enables Platinum‐Efficient Hydrogen Evolution in Pt‐Ag Bimetallic Nanowires

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.