Abstract
Propylene oxide (PO) is a key industrial chemical, often produced by epoxidizing propylene with H(2)O(2) over titanium silicalite-1. However, current H(2)O(2) production via the anthraquinone process relies on fossil-derived hydrogen, leading to substantial CO(2) emissions. Sustainable PO synthesis requires green H(2)O(2) production. Here, we present a fully unassisted, solar- and bias-free system that generates H(2)O(2). This platform enables modular, eco-friendly on-site PO synthesis by coupling formaldehyde oxidation with two-electron O(2) 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 H(2)O(2) 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.