Spatially Manipulating Polar Centers of Covalent Organic Frameworks for Boosting Hydrogen Peroxide Photosynthesis and Water Purification

Abstract

ABSTRACT Hydrogen peroxide (H 2 O 2 ) photosynthesis from H 2 O and O 2 using covalent organic frameworks (COFs) is a sustainable approach, yet its efficiency is restricted by a sluggish water oxidation reaction (WOR) due to insufficient water adsorption and charge separation. Herein, we propose a facile and universal polar center spatial‐manipulation strategy to enable efficient H 2 O 2 photosynthesis by COFs via converting high‐polarity C═N linkages into 4‐carboxyl‐quinolyl linkages with weakened‐polarity quinoline backbones and ultra‐polar carboxyl side chains (forming COF‐TBC). This polar‐center side‐shifting strategy concurrently enhances water adsorption (via the polar carboxyl side chain) and water activation (enabled by efficient exciton formation and separation along the low‐polarity quinoline backbone) by COF‐TBC, lowering the energy barrier of the rate‐determining WOR and achieving outstanding and stable H 2 O 2 photosynthesis from O 2 and H 2 O without sacrificial agents (5624 µmol g −1 h −1 , accumulating to 41 mM, solar‐to‐chemical efficiency of 0.72%). The polar‐center side‐shifting strategy can be extended to modify other COFs for enhancing H 2 O 2 photosynthesis, indicating its universality. COF‐TBC maintains high H 2 O 2 yield in complex real‐water matrices and can be integrated into membrane‐based and continuous‐flow reactors for successive H 2 O 2 generation under natural sunlight. COF‐TBC also exhibits efficient photocatalytic performance toward organic contaminant degradation and microorganism inactivation, highlighting its broad potential for water purification.