Construct an effective tandem reaction for epoxypropane production over 3D spherical C,O-In2S3 and TS-1 under visible light illumination

Traditional propylene oxide (PO) production processes consume large amounts of organic feedstock and release hazardous by-products. The synthesis of PO via the epoxidation of propylene using O 2 is an ideal route offering 100% atomic economy. However, achieving high selectivity and high efficiency under mild conditions remains a significant challenge. In this study, we have developed a visible-light-driven tandem reaction system combining a carbon- and oxygen-co-doped three-dimensional spherical indium sulfide (C,O-In 2 S 3 ) photocatalyst with titanium silicate molecular sieve (TS-1), thereby achieving the distinctly selective oxidation of propylene at ambient temperature. Assembled from ultra-thin nanosheets, the three-dimensional structure of C,O-In 2 S 3 provides abundant active sites and mass transfer space, with carbon‑oxygen co-doping narrowing the bandgap and enhancing visible light absorption. In a pure water system, the H 2 O 2 yield of C,O-In 2 S 3 reached 1450.40 μmol·g −1 ·h −1 , which is 17.8 times that of pristine In 2 S 3 . Utilizing the excellent compatibility of the methanol/water system, the photocatalytic generated H 2 O 2 was directly employed in the TS-1-catalysed epoxidation of propylene, achieving a PO yield of 2230.03 μmol·g −1 within 2 h with a selectivity of 99.1%. This work applies sulfide-based photocatalysts to a tandem reaction involving photocatalytic H 2 O 2 production and propylene epoxidation, providing a new strategy for the green, safe and efficient synthesis of PO.