A Hierarchical CdS Quantum Dot/Polymeric Carbon Nitride Nanosheet Heterostructure with Close Contact Interfaces for Enhanced Photocatalytic CO2 Reduction

Polymeric carbon nitride (PCN)-based materials have gained increasing attention as visible-light-responsive photocatalysts for solar energy conversion, but their limited light absorption ability and low photocatalytic performance are far from satisfactory. Herein, we reported a hierarchical CdS quantum dot/polymeric carbon nitride nanosheet heterojunction for notably enhanced CO2 conversion under visible light. Through a solvothermal process, the CdS quantum dots were uniformly distributed and tightly anchored over the surface of hierarchical PCN nanosheets, which are conducive for the formation of a close contact interface and the efficient transfer of the charge carriers across the interface. Furthermore, the optimal heterostructure owns a larger specific surface area, an enhanced light-harvesting capacity, a shortened charge transfer distance, and adequately exposed reaction sites. In consequence, the CO generation rate of the heterojunction reached 2810 mu mol g(-1) h(-1), which is nearly two times of that of the pure CdS photocatalysts and four times of that of the PCN nanosheets. This work provides an opportunity to get insight into the heterostructure between PCN and narrow-bandgap metal sulfide, which demonstrates a type I band alignment.