Boosting Exciton Dissociation and Charge Transfer in Fluorine-Substituted Covalent Organic Frameworks with Biomimetic Electron Pumps for Remarkable Photocatalytic Extraction of Uranium

Visible-light-driven photocatalytic uranium extraction based covalent organic frameworks (COFs) are green and sustainable, but their performance is severely restricted by a strong exciton effect. Herein, inspired by the physiology of cardiac pacing, a novel fluorine-based COF (PyF-DaS-COF) with a biomimetic electronic pump has been fabricated and used for the photocatalytic extraction of uranium. Both experimental and theoretical calculations confirm that strongly electronegative fluorine plays a crucial role in exciton dissociation and charge transfer. The enhanced electron push–pull effect increases the intrinsic separation driving force of charge separation. Furthermore, fluorine substitution thermodynamically favors the generation of the crucial *OOH intermediate in the uranium reduction reaction. As a result, the PyF-DaS-COF achieves a record k value (T = 293 K) of 0.082 min–1 with an extraction capacity of 991.5 mg g–1. Importantly, PyF-DaS-COF achieves a removal rate of over 99% in real uranium-containing wastewater. The current work provides unique insights into designing novel and effective COFs for controlling radioactive contamination.