Catalytic Conversion of Styrene to Benzaldehyde over S-Scheme Photocatalysts by Singlet Oxygen

Catalytic conversion of aromatic olefins into carbonyl compounds is a critical reaction in chemical industries. Herein, we constructed a series of pyrene-alt-dibenzothiophene-S,S-dioxide (P16PySO)/tungsten trioxide (WO3) composites to investigate the mechanism of photocatalytic styrene oxidation under anaerobic and aerobic conditions. The S-scheme charge transfer pathway within P16PySO/WO3 was systematically analyzed. Under anaerobic conditions, the optimized P16PySO/ WO3 photocatalyst exhibited a moderate styrene conversion rate with continuous H-2 evolution. Under aerobic conditions, the activity of styrene oxidation was promoted, but H-2 production was dramatically inhibited. The detection of reactive oxygen species and scavenger-assisted photocatalytic experiments revealed that triplet oxygen (O-3(2)) could efficiently trap the energy of triplet excited P16PySO through an energy transfer process and convert to singlet oxygen (O-1(2)). In situ diffuse reflectance infrared Fourier transform spectroscopy and density functional theory indicate that the highly reactive O-1(2) plays an important role in styrene oxidation to dioxetane intermediates, realizing selective cleavage of styrene.

Automated summary

This study constructed a series of pyrene-alt-dibenzothiophene-S,S-dioxide (P16PySO)/tungsten trioxide (WO3) composites to investigate the mechanism of photocatalytic styrene oxidation under anaerobic and aerobic conditions. The S-scheme charge transfer pathway within P16PySO/WO3 was systematically analyzed. The results revealed that triplet oxygen (O-3(2)) could efficiently trap the energy of triplet excited P16PySO through an energy transfer process and convert to singlet oxygen (O-1(2)), which played an important role in styrene oxidation.