Highly-configured TiO_2 hollow spheres adorned with N-doped carbon dots as a high-performance photocatalyst for solar-induced CO_2 reduction to methane

摘要

Transforming CO2 into solar fuel using renewable solar energy and a catalyst is an effective approach that simultaneously addresses energy scarcity and climate deterioration. Therefore, it is necessary, albeit challenging, to design a catalyst that works effectively for this purpose. Herein, we have rationally developed a hybrid catalyst composed of highly-configured TiO2 hollow spheres (TOH) and N-doped carbon dots (CD), referred to as CD/TOH, and use this hybrid as a catalyst for photocatalytic CO2 reduction to produce CH4 under simulated sunlight. The electron microscopy results revealed that the CD/TOH hybrid possesses a porous hollow sphere structure uniformly adorned with N-doped carbon dots. Moreover, the CD/TOH hybrid demonstrates many beneficial properties for CO2 photoreduction reactions, including a large surface area, effective light-harvesting capability, high CO2 adsorption, and, most importantly, significantly enhanced separation of photoexcited charges. Consequently, the CD/TOH containing 2 wt% CD achieves an optimum CH4 formation rate of 26.8 mu mol h(-1) g(-1), corresponding to 98% CH4 selectivity against competitive H-2 production. Further, the hybrid also demonstrated stable CO2 reduction activity during consecutive test runs. Thus, the insights gained from this study may aid in the development of effective catalysts for CO2 photoreduction.