Fast Crystallization of Fluorinated Covalent Organic Frameworks via a Steam-Assisted Conversion for Xe/Kr Separation

Area of Science:

• Materials Science
• Nanotechnology
• Chemical Engineering

Background:

• Covalent organic frameworks (COFs) are crucial for catalysis and separation.
• Traditional solvothermal synthesis limits the development of novel COFs, especially fluorinated COFs (FCOFs).

Purpose of the Study:

• To develop an innovative steam-assisted conversion (SAC) strategy for synthesizing FCOFs.
• To overcome the limitations of conventional solvothermal methods for FCOF fabrication.

Main Methods:

• Synthesized a series of FCOFs using the SAC strategy.
• Utilized ultralow-dose high-resolution transmission electron microscopy for real-space imaging.
• Evaluated Xe/Kr separation performance and gamma-irradiation tolerance.

Main Results:

• Successfully synthesized novel FCOFs (4F-LZU-1-COF, 4F-SHTA-Pa-COF, 4F-DHTA-Pa-COF) with superior crystallinity.
• The SAC method proved to be mild, rapid, and environmentally friendly.
• FCOFs exhibited efficient Xe/Kr separation and high tolerance to gamma irradiation.

Conclusions:

• The SAC strategy is a viable and scalable route for synthesizing robust FCOFs.
• This approach broadens COF fabrication scope and opens new application avenues, particularly for radioactive effluent gas treatment.