Plasmonically Enhanced Hydrogen Evolution on Anisotropic AuPt Nanowires with Submonolayer Pt Surface Coverage

The rational design of electrocatalysts that efficiently harness plasmonic excitation for electrocatalytic hydrogen production from water remains challenging. Here, guided by density functional theory (DFT) predictions, anisotropic AuPt nanowires are systematically synthesized with precise monolayer and submonolayer Pt surface coverage on Au nanowire templates. Under visible-light-driven plasmonic excitation, these catalysts exhibited high hydrogen evolution reaction (HER) activity, achieving mass activities up to 9.3 A mg^-1 _Pt at -0.05 V vs RHE, representing a ≈7-fold enhancement over commercial Pt/C catalysts and surpassing spherical AuPt nanoparticles. Detailed electron microscopy, spectroscopy, and electrochemical analyses indicated that the submonolayer Pt coverage provided more isolated catalytic sites, optimal electronic coupling, and preserved plasmonic properties. DFT calculations reveal pronounced electronic redistribution at Au-Pt interfaces, raise Pt d-band centers, and ideal Gibbs free energies for hydrogen adsorption. This synergistic combination of catalytic and plasmonic properties represents a promising strategy to substantially reduce precious metal usage without compromising catalytic performance, offering a robust framework for designing electrocatalysts for renewable energy conversion.