Tandem photocatalytic production of H2O2 and propylene oxide on 5-Bromoisatin modified carbon nitride

Propylene oxide (PO) is an important raw material and synthetic intermediate for organic chemical synthesis. The direct in-situ synthesis of hydrogen peroxide (H2O2) using molecular oxygen to produce PO is considered as one of the most promising methods. Herein, we propose a photocatalytic multiphase system for the production of PO with oxygen. The ligand 5-bromoindoline-2,3-dione doped graphitic carbon nitride (CN/Bd) was employed as a photocatalyst for the in-situ production of H2O2, in tandem with epoxidation catalyst titanium silicalite-1 (TS-1) to achieve the epoxidation of propylene. This system achieved H2-free and efficient production of PO at room temperature with a high yield of 1.33 mmol·g−1·h−1, the selectivity of PO over 99% and H2O2 utilization efficiency over 95%. The combination of in-situ H2O2 generation and selective oxidation reaction realizes the efficient utilization of H2O2 and provides guidance for safer industrial production of PO.