Guest-Induced Structural Torsion in Single Covalent Organic Frameworks for Enhanced Photocatalysis
Yang Liu1,2, Hongbing Chi1, Yifei Tan1
1School of Nuclear Science & Technology, Southwest University of Science and Technology, Mianyang 621010, P. R. China.
Nano Letters
|July 14, 2025
Summary
We discovered that twisting covalent organic framework (COF) structures by adding guests enhances their photocatalytic activity. This twist engineering strategy enables efficient removal of radioactive iodine at the picogram level.
Area of Science:
- Materials Science
- Chemistry
- Nanotechnology
Background:
- Understanding structure-activity relationships in covalent organic frameworks (COFs) is key for optimizing photocatalysis.
- Real-time monitoring of individual COF photocatalysts provides crucial mechanistic insights.
Purpose of the Study:
- To investigate guest-induced structural changes in COF-300 microcrystals.
- To enhance the photocatalytic performance of COF-300 through structural modification.
- To establish a general strategy for designing efficient COF photocatalysts.
Main Methods:
- In situ dark-field optical microscopy (DFM) for real-time imaging of single COF microcrystals.
- Host-guest encapsulation of ethyl acetate (EAC) into COF-300.
- Spectroscopic characterizations and theoretical calculations.
- Photocatalytic degradation experiments, including removal of radioactive 131I-.
Main Results:
- Ethyl acetate encapsulation induced structural torsion in COF-300, forming EAC@COF-300 microcrystals with twisted diimine linkers.
- This structural twist transformed COF-300 from an inert to an active photocatalyst.
- The twisted EAC@COF-300 exhibited enhanced intersystem crossing and spin-orbit coupling, improving photogenerated charge separation.
- Achieved highly efficient photocatalytic removal of radioactive 131I- at the picogram level.
Conclusions:
- Guest-induced structural torsion is a viable strategy for enhancing COF photocatalyst performance.
- Twist engineering of COFs offers a general approach for designing advanced photocatalytic materials.
- The developed method demonstrates potential for environmental remediation applications, such as radioactive waste treatment.
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