Spatially Decoupled Capture-Conversion Architectures for Photocatalytic Uranium Extraction from Dilute Wastewater

Integrating adsorption motifs with photocatalytic units into capture-conversion architectures can, in principle, enhance photocatalytic uranium extraction from dilute wastewater. However, whether their spatial relationship promotes synergy or causes mutual interference remains unclear. Here, we employ a family of isomeric covalent organic frameworks (TpBpy4, TpBpy5, and TpBpy6) as a model platform to program site-overlapped/proximate (TpBpy4 and TpBpy5) and site-decoupled (TpBpy6) relationships between UO 2 2+ adsorption motifs and photocatalytic oxygen reduction sites. The site-decoupled TpBpy6 suppresses mutual interference between UO 2 2+ capture and oxygen reduction, sustaining in situ photocatalytic H 2 O 2 generation and enabling continuous conversion of captured UO 2 2+ into insoluble studtite ((UO 2 )(O 2 )·4H 2 O), whereas TpBpy4 and TpBpy5 suffer from UO 2 2+ -induced suppression of photocatalytic activity that interrupts the capture-conversion cycle. Under low-ppm UO 2 2+ concentrations, TpBpy6 delivers a 1.83-fold higher extraction efficiency than the site-overlapped analogue TpBpy5 and achieves a capacity of 51.7 mg g –1 from actual dilute mining wastewater. This work reveals that overall performance is governed by the interplay between adsorption and photocatalytic sites and establishes a spatial decoupling design principle for minimizing mutual interference while preserving functional synergy in photocatalytic extraction systems for valuable resource recovery from dilute effluents.