Polarization‐π Strategy for Modulating Excited‐State Band Structures of Covalent Organic Frameworks to Enhance Photocatalytic Uranium Extraction

Abstract Covalent organic frameworks (COFs) have emerged as promising photocatalysts for uranium extraction due to their ordered porosity, tunable electronic structures, and abundant functional sites. However, achieving efficient exciton dissociation and optimized carrier dynamics remains challenging. This study presents a breakthrough polarization‐π strategy that simultaneously modulates both ground‐state and excited‐state bandgap structures of COFs. By ingeniously combining enhanced π‐conjugation with induced polarization through molecular engineering, the developed thiophene‐based COF BTT‐COF‐AO realizes remarkable electronic structure optimization. The synergistic effects not only regulate ground‐state energy levels but more importantly, significantly reduce excited‐state bandgap levels, a critical yet often overlooked factor in photocatalytic performance. This dual modulation leads to substantially decreased exciton binding energy while dramatically enhancing exciton dissociation and charge carrier transport. The resulting photocatalyst achieves an unprecedented uranium adsorption capacity of 650.60 mg g −1 in nuclear‐contaminated water containing competitive ions, setting a break‐recording value among the amidoxime group‐based materials. This work provides a novel approach for developing high‐performance photocatalytic materials, paving the way for future advancements in uranium resource recycling.