Improved Plasmonic Hot-Electron Capture in Au Nanoparticle/Polymeric Carbon Nitride by Pt Single Atoms for Broad-Spectrum Photocatalytic H₂ Evolution

Rationally designing broad-spectrum photocatalysts to harvest whole visible-light region photons and enhance solar energy conversion is a "holy grail" for researchers, but is still a challenging issue. Herein, based on the common polymeric carbon nitride (PCN), a hybrid co-catalysts system comprising plasmonic Au nanoparticles (NPs) and atomically dispersed Pt single atoms (PtSAs) with different functions was constructed to address this challenge. For the dual co-catalysts decorated PCN (PtSAs-Au_2.5/PCN), the PCN is photoexcited to generate electrons under UV and short-wavelength visible light, and the synergetic Au NPs and PtSAs not only accelerate charge separation and transfer though Schottky junctions and metal-support bond but also act as the co-catalysts for H₂ evolution. Furthermore, the Au NPs absorb long-wavelength visible light owing to its localized surface plasmon resonance, and the adjacent PtSAs trap the plasmonic hot-electrons for H₂ evolution via direct electron transfer effect. Consequently, the PtSAs-Au_2.5/PCN exhibits excellent broad-spectrum photocatalytic H₂ evolution activity with the H₂ evolution rate of 8.8 mmol g^-1 h^-1 at 420 nm and 264 μmol g^-1 h^-1 at 550 nm, much higher than that of Au_2.5/PCN and PtSAs-PCN, respectively. This work provides a new strategy to design broad-spectrum photocatalysts for energy conversion reaction.