Near-Infrared-Driven Photoelectrochemical Hydrogen Evolution Reaction Enabled by Plasmonic Gold Nanocone Arrays with High Curvatures

Harvesting a wide range of light is essential for photo-driven reactions. In this study, the near-infrared (NIR, λ ≥ 800 nm) driven photoelectrochemical (PEC) hydrogen evolution enabled by the design of gold nanocone (AuNC) arrays with high curvature is reported. It is found that the synergistic interplay between static geometric fields (tip curvature-derived) and spectrally responsive localized surface plasmon resonance dynamic fields drives reactant enrichment at nanocone surfaces and that the array structure enhances the light absorption of AuNC due to the plasmonic collective effect, together promoting the efficiency of PEC hydrogen evolution under visible light and enabling the NIR-driven PEC hydrogen evolution, which otherwise cannot be achieved by the Au nanoparticle photocathode. As a prototype electrocatalyst, RuO₂ is further loaded onto AuNC to create a plasmonic antenna-reactor (AuNC-Ru), which exhibits substantially higher PEC performance than the AuNP-Ru, achieving an overpotential of 25 and 27 mV at 10 mA cm⁻² for the hydrogen evolution reaction in alkaline under visible light and NIR irradiation, respectively. In addition, the stability of AuNC-Ru exceeds 500 h at 10 mA cm⁻² and 120 h at 100 mA cm⁻².