Boosting Exciton\nDissociation and Charge Transfer\nin Fluorine-Substituted Covalent Organic Frameworks with Biomimetic\nElectron Pumps for Remarkable Photocatalytic Extraction of Uranium

Visible-light-driven photocatalytic uranium extraction\nbased covalent\norganic frameworks (COFs) are green and sustainable, but their performance\nis severely restricted by a strong exciton effect. Herein, inspired\nby the physiology of cardiac pacing, a novel fluorine-based COF (PyF-DaS-COF)\nwith a biomimetic electronic pump has been fabricated and used for\nthe photocatalytic extraction of uranium. Both experimental and theoretical\ncalculations confirm that strongly electronegative fluorine plays\na crucial role in exciton dissociation and charge transfer. The enhanced\nelectron push–pull effect increases the intrinsic separation\ndriving force of charge separation. Furthermore, fluorine substitution\nthermodynamically favors the generation of the crucial *OOH intermediate\nin the uranium reduction reaction. As a result, the PyF-DaS-COF achieves\na record <i>k</i> value (<i>T</i> = 293 K) of\n0.082 min<sup>–1</sup> with an extraction capacity of 991.5\nmg g<sup>–1</sup>. Importantly, PyF-DaS-COF achieves a removal\nrate of over 99% in real uranium-containing wastewater. The current\nwork provides unique insights into designing novel and effective COFs\nfor controlling radioactive contamination.