Tuning Local Charge Distribution in Multicomponent Covalent Organic Frameworks for Dramatically Enhanced Photocatalytic Uranium Extraction

Optimizing the electronic structure of covalent organic framework (COF) photocatalysts is essential for maximizing photocatalytic activity. Herein, we report an isoreticular family of multivariate COFs containing chromenoquinoline rings in the COF structure and electron-donating or withdrawing groups in the pores. Intramolecular donor-acceptor (D-A) interactions in the COFs allowed tuning of local charge distributions and charge carrier separation under visible light irradiation, resulting in enhanced photocatalytic performance. By optimizing the optoelectronic properties of the COFs, a photocatalytic uranium extraction efficiency of 8.02 mg/g/day was achieved using a nitro-functionalized multicomponent COF in natural seawater, exceeding the performance of all COFs reported to date. Results demonstrate an effective design strategy towards high-activity COF photocatalysts with intramolecular D-A structures not easily accessible using traditional synthetic approaches.

Automated summary

In this study, an isoreticular family of multivariate COFs with chromenoquinoline rings and electron-donating or withdrawing groups were synthesized and used as photocatalysts. The intramolecular donor-acceptor interactions in the COFs enabled tuning of charge distribution and carrier separation, leading to improved photocatalytic performance. By optimizing the optoelectronic properties, a nitro-functionalized multicomponent COF achieved a photocatalytic uranium extraction efficiency of 8.02 mg/g/day in natural seawater, surpassing all previously reported COFs. These findings demonstrate an effective design strategy for high-activity COF photocatalysts with intramolecular D-A structures not easily accessible through traditional synthetic methods.