Hierarchical hollow-microsphere cadmium sulfide-carbon dots composites with enhancing charge transfer efficiency for photocatalytic CO2 reduction

Construction of hierarchical heterostructure is considered as a promising approach to promote photocatalytic CO2 reduction, yet the report about CdS semiconductor for photocatalytic activity is still restricted caused by its rapid charge recombination. Herein, a novel carbon dots (CDs) modified CdS hollow sphere (CDs/CdS) has been successfully synthesized by multi-step including template-assembly, template-removal, and ultrasonic impregnation processes. This noble-metal-free heterostructure exhibits significantly improved solar-driven CO2 reduction performance, and the optimal CDs/CdS presents CO yield rate of 16.09 μmol g−1 h−1, which is nearly 4 times higher than that of pristine CdS hollow sphere under the same condition. The excellent performance and stability of CDs/CdS are due to the formed hollow sphere and seamless contact, which can possess large inner space, intimate interfacial contact for charge transport and improve concentration of sacrificial agent. Meanwhile, CDs as cocatalyst can boost the charge separation and stabilize the electrons. This study can afford a feasible perspective to design and fabricate high-efficient catalyst for CO2 photoreduction.