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

Abstract

Propylene oxide (PO) is an important raw material in the plastics industry. The propylene epoxidation using O 2 without H 2 and noble metals is considered a fantasy reaction. Here we constructed a tandem system for photocatalytic in situ H 2 O 2 production and propylene epoxidation. In this tandem transformation system, we prepared carbon nitride containing N 3C vacancies in one step by the synergistic action of argon pyrolysis and a supramolecular self-assembly precursor. The introduction of N 3C vacancies significantly promoted the photogenerated electron–hole separation and enhanced the adsorption of H + and O 2 for excellent photocatalytic H 2 O 2 performance (5775 μmol/g/h) via the dual paths involving · O 2 – and 1 O 2 . To avoid the separation and purification of H 2 O 2, a compatible solvent system consisting of methanol and water was utilized to promote the production of both H 2 O 2 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 O 2 but also provided a reference for creating more propylene epoxidation systems in series with photosynthetic H 2 O 2 .