Boosting C<sub>3</sub>H<sub>6</sub> Epoxidation via Tandem Photocatalytic H<sub>2</sub>O<sub>2</sub> Production over Nitrogen-Vacancy Carbon Nitride
Qinhua Zhang, Longjian Li, Qiang Zhou, Haonan Zhang, Hangkai Zhang, Bo An, Hui Ning, Tao Xing, Mingqing Wang, Mingbo Wu, Wenting Wu
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 .