Fluorinated porous organic frameworks for improved CO₂ and CH₄ capture

Area of Science:

• Materials Science
• Chemical Engineering
• Environmental Science

Background:

• Porous organic frameworks (POFs) are advanced materials for gas separation.
• Tailoring framework properties is crucial for enhancing adsorption selectivity.
• Fluorination offers a strategy to modify material polarity and interaction potential.

Purpose of the Study:

• To synthesize novel fluorinated porous organic frameworks (F-POFs).
• To investigate the impact of C-F dipole incorporation on CO2 adsorption properties.
• To evaluate the CO2/N2 selectivity and methane interaction energies of F-POFs.

Main Methods:

• Condensation polymerization of fluorinated tetraphenylmethane (TPM) monomers.
• Synthesis of F-POFs with controlled C-F dipole distribution and density.
• Gas adsorption isotherms and selectivity measurements (CO2/N2).

Main Results:

• A robust and flexible F-POF (F-PAF1) with a surface area of 2050 m2 g-1 was synthesized.
• Moderate C-F dipole insertion increased the isosteric heat of CO2 adsorption by 53%.
• CO2/N2 selectivity reached up to 50 with difluoro-containing comonomers; methane interaction energies were optimal at 24 kJ mol-1.

Conclusions:

• Selective fluorination of POFs is an effective strategy to enhance CO2 capture performance.
• The controlled insertion of C-F dipoles significantly improves CO2 adsorption thermodynamics and selectivity.
• These F-POFs show promise for selective CO2 separation and methane storage applications.