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

ABSTRACT

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.