Synergetic enhancement of plasmonic hot-electron injection in Au cluster-nanoparticle/C3N4 for photocatalytic hydrogen evolution

Abstract

Photocatalytic hydrogen evolution driven by abundant sunlight is critical for the effective conversion of renewable energy. Here, we present a combination of Au clusters and nanoparticles (NPs) on a graphitic carbon nitride (g-C₃N₄) semiconductor to achieve efficient plasmonic hot electron injection for realizing high visible and near-infrared photocatalytic hydrogen evolution activity. Ultraviolet photoelectron and transient photovoltage spectroscopy demonstrate that the synergetic electron coupling between Au clusters and NPs via strong sp² hybridization with the C₃N₄ host could effectively tune the semiconductor work function for reducing the metal/semiconductor interfacial Schottky barrier by 0.6 eV, which greatly shortens the injection time and prolongs the average lifetime of energetic hot electrons in C₃N₄ by one order of magnitude under visible and near-infrared irradiation. Hence, the as-obtained Au cluster-NP/C₃N₄ photocatalyst achieves a prominent photocatalytic H₂ production rate of 230 μmol g⁻¹ h⁻¹ in the light absorption range of 400–900 nm, which is 6–20 times those of its Au NP/C₃N₄ and Au cluster/C₃N₄ counterparts.