Amorphous-crystalline transition-induced hollowing of covalent organic frameworks: a structural evolution boosting
Cuicui Shao1, Zhijian Li1, Yuxin Sun1
1Jiangxi Province Key Laboratory of Organic Functional Molecules, Institute of Organic Chemistry, Jiangxi Science and Technology Normal University, Nanchang, 330013, P. R. China. lizhijianhdd@163.com.
Materials Horizons
|December 2, 2025
Summary
A novel self-template method creates stable hollow covalent organic frameworks (COFs) using Ostwald ripening. These hollow COFs show enhanced uranium adsorption, offering a promising strategy for efficient removal.
Area of Science:
- Materials Science
- Nanotechnology
- Environmental Chemistry
Background:
- Hollow covalent organic frameworks (COFs) offer unique structural advantages for various applications.
- Controllable synthesis of uniform and stable hollow COFs presents a significant challenge in materials science.
Purpose of the Study:
- To develop a facile and effective self-template method for preparing hollow COFs.
- To investigate the morphological evolution and structural properties of the synthesized hollow COFs.
- To evaluate the uranium adsorption performance of hollow COFs functionalized with phosphate groups.
Main Methods:
- Utilized Ostwald ripening mechanism under environmental conditions for self-templating.
- Employed time-resolved structural analyses to track morphological changes from solid to hollow structures.
- Synthesized phosphorylated hollow COFs (PA-H-COF) for uranium adsorption studies.
Main Results:
- Achieved hierarchical hollow-flower COFs (H-COF) with high crystallinity and a specific surface area of 534.99 m² g⁻¹.
- Demonstrated superior uranium adsorption capacity (296.7 mg g⁻¹) for PA-H-COF compared to non-hollow counterparts.
- Observed significant uranium adsorption (7.38 mg g⁻¹) from actual seawater within 20 days.
Conclusions:
- The proposed self-template method provides a viable route to uniform and stable hollow COFs.
- The hierarchical structure of hollow COFs enhances active site exposure, leading to improved uranium adsorption.
- Hollow phosphate functionalized COFs show great potential for efficient uranium removal from aqueous solutions.
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