0D-2D S-scheme CdS/WO3 catalyst for efficiently boosting CO2 photoreduction

Abstract

Improving the dispersion of active sites and photogenerated carriers’ separation efficiency are of significant for enhancing the CO2 photoreduction. In this research, Zero-dimensional/Two-dimensional (0D-2D) S-scheme CdS/WO3 photocatalysts have been successfully obtained via the simple hydrothermal method and successive ionic layer adsorption reaction. SEM and TEM images provide that CdS Quantum Dots (QDs) are uniformly dispersed on the surface of WO3 nanosheets. WO3 nanosheets can greatly improve the dispersion of the CdS QDs, which can enlarge the adsorption and reaction efficiency of CO2 at the photoreduction sites. CO2 photoreduction tests show that the CdS/WO3 (CW-2) composite expresses excellent CO2 photoreduction ability and great catalytic stability. The yields of CO and CH4 with the CW-2 as catalyst are 64.7 μmol/g·h and 2.3 μmol/g·h, which are about 4.0 and 2.7 times more potent than that of CdS QDs. 13C calibration experiment proves that the C-source of CO and CH4 are obtained by the CO2 photoreduction process. Density functional theory calculation and electron spin resource results confirm the formation of S-scheme heterojunction. A potential synergistic effect of highly dispersed active sites and the S-scheme heterojunction has been provided for enhanced CO2 photoreduction performance.