Boosting C3H6 Epoxidation via Tandem Photocatalytic H2O2 Production over Nitrogen-Vacancy Carbon Nitride

Propylene oxide (PO) is an important raw material in the plastics industry. The propylene epoxidation using O2 without H2 and noble metals is considered a fantasy reaction. Here we constructed a tandem system for photocatalytic in situ H2O2 production and propylene epoxidation. In this tandem transformation system, we prepared carbon nitride containing N3C vacancies in one step by the synergistic action of argon pyrolysis and a supramolecular self-assembly precursor. The introduction of N3C vacancies significantly promoted the photogenerated electron–hole separation and enhanced the adsorption of H+ and O2 for excellent photocatalytic H2O2 performance (5775 μmol/g/h) via the dual paths involving ·O2– and 1O2. To avoid the separation and purification of H2O2, a compatible solvent system consisting of methanol and water was utilized to promote the production of both H2O2 and PO. Benefiting from them, the PO production efficiency came to 5515 μmol/g/h with a selectivity of 99.1%. This work not only opened up an idea for propylene epoxidation using O2 but also provided a reference for creating more propylene epoxidation systems in series with photosynthetic H2O2.