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

Abstract

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.