Integrating Uranyl-Affinity “Hooks” into Conjugated Polymers Achieving Giant Built-in Electric Field for Boosting Photocatalytic Uranium Extraction from Seawater

Insufficient charge separation and sluggish exciton transport seriously restrict the practical application of photocatalytic uranium extraction from seawater. In this study, a D-π-A conjugated microporous polymer is synthesized using perylene, phosphonate-containing fluorene, and benzothiadiazole as D, π-linker, and A units, respectively, as novel uranium extraction photocatalysts. Both experimental and theoretical studies have demonstrated that the D-π-A structure simultaneously expands π-electron delocalization and promotes intramolecular charge transfer, thus accelerating the photocatalytic reaction. More importantly, phosphate ester and benzothiadiazole together act as uranyl-affinity “hooks” in the skeleton, adding the asymmetry and expanding the built-in electric field, thereby enhancing the driving force of photogenerated charge separation and elevating the charge separation efficiency (84.8%). The results show that the photocatalytic uranium extraction capacity of CMP-D-π′-A reaches 11.68 ± 0.21 mg g –1, exceeding most reported photocatalysts. These findings provide a promising avenue for the development of uranium extraction materials through regulating the interfacial electric field.