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 (WO 3 ) composites to investigate the mechanism of photocatalytic styrene oxidation under anaerobic and aerobic conditions. The S-scheme charge transfer pathway within P16PySO/WO 3 was systematically analyzed. Under anaerobic conditions, the optimized P16PySO/WO 3 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 ( 3 O 2 ) could efficiently trap the energy of triplet excited P16PySO through an energy transfer process and convert to singlet oxygen ( 1 O 2 ). In situ diffuse reflectance infrared Fourier transform spectroscopy and density functional theory indicate that the highly reactive 1 O 2 plays an important role in styrene oxidation to dioxetane intermediates, realizing selective cleavage of styrene.