Conjugated organic polymer enables external-sacrificial-agent-free photocatalytic uranium extraction with efficiency...

Efficient extraction of uranium from seawater is critical for sustainable nuclear energy. Photocatalysis offers a promising route, while the reliance on sacrificial agents and the limited extraction capacity necessitate the development of new photocatalysts. Here, we report the first conjugated organic polymer (COP), BB-COP-AO, that enables external-sacrificial-agent-free photocatalytic uranium extraction from natural seawater. Rational incorporation of benzothiadiazole and pyridine units optimizes the band structure, enhances intramolecular donor-acceptor interactions, and facilitates charge separation, endowing it with high photocatalytic activity. Pyridine nitrogen atoms benefit dissolved oxygen adsorption and pre-activation to promote ·O₂^- generation, boosting the uranium recovery efficiency. Furthermore, the suitable valence band enables photogenerated holes to oxidize H₂O to H₂O₂, thereby eliminating the need for external sacrificial agents. Concurrently, amidoxime functionalities ensure selective uranyl binding. Consequently, BB-COP-AO drives selective conversion of the uranyl ions into highly stable metastudtite via a dual-pathway mechanism coupling dissolved oxygen activation and water oxidation. Benefiting from these synergistic effects, BB-COP-AO exhibits an outstanding uranium extraction capacity of 19.80 mg g^-1 in natural seawater within 7 d, along with excellent selectivity and recyclability. This work expands the application scope of COP-based materials and offers a generalizable molecular design strategy for developing multifunctional photocatalysts toward sustainable uranium recovery from seawater.