Morphology Controlled Covalent Organic Framework Nano‐Trap for Synergetic Uranium Adsorption and Photoreduction

Abstract Covalent organic frameworks (COFs) without donor–acceptor pairs or inefficient separation of photogenerated electrons are usually considered unfavorable for photocatalysis due to electron‐hole recombination. However, the study demonstrates a nitrile (CN) functionalized covalent organic framework nano‐traps (COF‐nTs; COF‐nTS 1 , COF‐nTS 2 , and COF‐nTS 3 ), in which the CN groups act as electron‐withdrawing centers, surrounding electron and facilitating charge separation, transport, and adsorption process. To further enhance the efficiency of charge carriers, a special approach is introduced to integrate morphology control through acid regulation and defect engineering. These key strategies optimize the key structure and improve photocatalytic performance, achieving a maximum uranium extraction capacity of 3548.1 mg g −1 , which is significantly higher than previously reported COF‐based photocatalysts under visible light. A flexible 3 × 6 cm film of COF‐nTs 3 is prepared by the blade coating method, successfully extracting uranium from spiked seawater with a 7‐day capacity of 76 mg g −1 , a saturation capacity of 193 mg g −1 , and 0.2 day half saturation time. This demonstrates its potential for uranium extraction from aqueous solutions.