Nature-Inspired Pyrylium Cation-Based Vinylene-Linked Two-Dimensional Covalent Organic Framework for Efficient Sunlight-Driven Water Purification

Sunlight-driven photocatalytic water purification for the removal of persistent organic compounds and microorganisms has been widely regarded as a promising technology due to the low energy consumption and environmental friendliness; however, it calls for efficient and sustainable photocatalysts. Pyrylium cation is a photoactive component of many naturally occurring dyes in fruits, flowers, and leaves. Herein, we report the synthesis of a novel pyrylium cation contained vinylene-linked two-dimensional covalent organic framework (v-2D-COF-O1) via aldol-type polycondensation. The resultant v-2D-COF-O1 has a narrow band gap (1.15 eV) and wide-range light absorption up to ∼920 nm. More importantly, the v-2D-COF-O1 can activate molecular oxygen to generate highly reactive oxygen species including superoxide (•O2-) and hydroxyl radicals (•OH) under simulated sunlight (AM 1.5 G), which leads to remarkable photocatalytic activities in both organic waste decomposition and water disinfection. These results suggest the potential of v-2D-COFs as high-performance photocatalysts for water purification.