Tungsten bronze Cs0.33WO3 nanorods modified by molybdenum for improved photocatalytic CO2 reduction directly from air

Abstract

Photocatalytic CO2 reduction is thought to be a promising strategy in mitigating the energy crisis and several other environmental problems. Hence, modifying or developing suitable semiconductors with high efficiency of photocatalytic CO2 reduction property has become a topic of interest to scientists. In this study, a series of Mo-modified Cs0.33WO3 tungsten bronze were prepared using a “water-controllable releasing” solvothermal method to produce effective photocatalytic CO2 reduction performance. Interestingly, Mo atoms replaced W partially within the hexagonal crystal structure, leading to a significant increase in photocatalytic CO2 reduction activity of Cs0.33WO3. The 5% Modoped compound displayed the best performance, with the production yield rates of 7.5 µmol g−1 h−1 for CO and 3.0 µmol g−1 h−1 for CH3OH under low concentration of CO2 under anaerobic conditions, which is greatly higher than those of pure Cs0.33WO3 (3.2 µmol g−1 h−1 for CO and 1.2 µmol g−1h−1 for CH3OH) and Mo-doped W18O49 (1.5 µmol g−1 h−1 for CO and 0 µmol g−1 h−1 for CH3OH). More importantly, the as-prepared Mo-doped Cs0.33WO3 series could also induce the photocatalytic reduction of CO2 directly from the air in the presence of oxygen, which is beneficial for practical applications. The superior photocatalytic performance of Mo-doped Cs0.33WO3 series over the popular reduced WO3 may be due to the increase in light absorption induced by the localized surface plasmon resonance (LSPR) effect of Mo5+, large improved charge separation ability, and the co-effect of Mo and Cs in crystal. This study provides a simple strategy for designing highly efficient photocatalysts in low concentration of CO2 reduction.