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

Abstract

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.