Tailoring Polyarylether‐Based Covalent Organic Frameworks Governs Charge Dynamics and Oxygen Activation for Enhanced Photocatalytic Water Decontamination

By virtue of their photocatalytic reactive oxygen species (ROS) generation ability, covalent organic frameworks (COFs) hold great potential for degrading emerging contaminants (ECs) in water. Nevertheless, their performance is often limited by insufficient and unsustainable ROS production, primarily due to sluggish charge dynamics, inadequate oxygen (O 2 ) activation, and poor structural stability. Herein, featuring highly stable and fully planar backbones, we developed two polyarylether‐linked COFs for enhanced water purification through functional group modulation, namely cyano‐modified PAE‐COF‐CN and carboxyl‐modified PAE‐COF‐COOH. Under visible light irradiation for 60 min, PAE‐COF‐CN achieved 94.1% removal (rate constant: 3.24 h −1 ) and 76.0% mineralization of an antibiotic EC, significantly outperforming PAE‐COF‐COOH (31.3%, 0.33 h −1 and 23.0%, respectively) and commonly reported organic photocatalysts. Combined experimental and theoretical investigations revealed that the superior photocatalytic degradation performance of PAE‐COF‐CN primarily stemmed from the cyano modification‐induced improvements in exciton dissociation, charge carrier transfer, and O 2 activation, thereby enhancing ROS generation (particularly superoxide radicals) that played a key role in the degradation process. Degradation pathway analysis and toxicity evaluation further confirmed effective detoxification in the PAE‐COF‐CN system. Moreover, this system exhibited excellent durability, broad applicability across diverse water matrices, and robust performance in natural sunlight‐driven scaled‐up and continuous‐flow experiments.