Self-driven propylene epoxidation on modified titanium silicalite-1 by in situ generated hydrogen peroxide

Propylene oxide (PO) is a key industrial chemical, often produced by epoxidizing propylene with H₂O₂ over titanium silicalite-1. However, current H₂O₂ production via the anthraquinone process relies on fossil-derived hydrogen, leading to substantial CO₂ emissions. Sustainable PO synthesis requires green H₂O₂ production. Here, we present a fully unassisted, solar- and bias-free system that generates H₂O₂. This platform enables modular, eco-friendly on-site PO synthesis by coupling formaldehyde oxidation with two-electron O₂ reduction under alkaline conditions. Efficient propylene epoxidation under these conditions is achieved using titanium silicalite-1 modified by introducing dinuclear titanium sites with Ti-O-Ti bonds, as revealed by density functional theory and instrumental analyses. The unassisted H₂O₂ production system is integrated with the modified titanium silicalite-1 to realize continuous PO production (1657 μmol_PO cm^-2 over 24 h), without electric or solar energy input. This unassisted PO production method can thus be energy-independent, offering a sustainable alternative to conventional processes.