Yolk-Shelled Gold@Cuprous Oxide Nanostructures with Hot Carriers Boosting Photocatalytic Performance

Plasmonic Au nanoparticles (NPs) have been commonly used to enhance the photocatalytic activity of Cu₂O. Till now, core-shell Au NP@Cu₂O composites have been reported in previous studies. Yet, these Au@Cu₂O composites only exhibit visible light response. Other special Au nanostructures, such as Au nanorods (NRs) or Au nanobipyramids (NBPs), which possess near-infrared light absorption, were rarely used to endow the near-infrared light response for Cu₂O. In this work, for the first time, we used Au NPs, Au NRs, and Au NBPs and employed a handy and universal method to synthesize a series of yolk-shelled Au@Cu₂O composites. The results showed that the yolk-shelled Au@Cu₂O composites had much higher photocatalytic activity than their solid-shelled ones and pure Cu₂O. More importantly, yolk-shelled Au NR@Cu₂O and Au NBP@Cu₂O composites indeed presented excellent near-infrared light-driven photocatalytic activity, which were impossible for Au NP@Cu₂O and pure Cu₂O. This outstanding performance for yolk-shelled Au NR@Cu₂O and Au NBP@Cu₂O could be attributed to the transfer of abundant hot electrons from Au NRs or Au NBPs to Cu₂O, and the timely utilization of hot holes on Au through the rich pore channels on their yolk-shelled structure. Furthermore, yolk-shelled Au@Cu₂O also showed better stability than pure Cu₂O, owing to the migration of the oxidizing holes from Cu₂O to Au driven by the built-in electric field. This work may give a guide to fabricate controllable and effective photocatalysts based on plasmonic metals and semiconductors with full solar light-driven photocatalytic activities in the future.