Direct propylene epoxidation with oxygen using a photo-electro-heterogeneous catalytic system

Propylene oxide is a crucial feedstock in the plastic industry. The direct epoxidation of propylene using O2 is considered among the most promising means of producing propylene oxide. Here we report an integrated photo-electro-heterogeneous catalytic system for propylene epoxidation with O2. Bismuth vanadate (or TiO2) photocatalyst and a Co-based electrocatalyst produces H2O2. A titanium silicalite-1 heterogeneous catalyst subsequently epoxidizes propylene to propylene oxide with the in situ-generated H2O2. The proposed system enables propylene oxide production with O2 as the sole oxidizing agent under light irradiation without using H2, a sacrificial agent, or external bias. It stably produces propylene oxide for 24 h with high selectivity (≥98%) under ambient conditions. These results demonstrate the potential of this catalytic system to produce chemical compounds in an environmentally benign manner. Aerobic oxidation of propylene is a potential green route to propylene oxide production without the need for harmful oxidizing or wasteful sacrificial reagents. Here, a proof-of-concept integrated photo-electro-heterogeneous catalytic system performs this reaction using in situ-generated H2O2.