Finding MOFs for highly selective CO2/N2 adsorption using materials screening based on efficient assignment of atomic...

Area of Science:

• Materials Science
• Computational Chemistry
• Chemical Engineering

Background:

• Electrostatic interactions significantly influence the adsorption of quadrupolar molecules like CO2 and N2 in nanoporous materials.
• Metal-organic frameworks (MOFs) are promising materials for gas adsorption applications.

Purpose of the Study:

• To develop and apply an efficient computational method for predicting CO2 and N2 adsorption in a large number of MOFs.
• To identify MOFs with high CO2/N2 selectivity and suitable diffusion properties for CO2 capture.

Main Methods:

• Utilized a semiempirical charge equilibration method adapted for periodic materials to assign atomic charges.
• Performed molecular simulations for CO2 and N2 adsorption in approximately 500 MOFs.
• Conducted detailed quantum chemistry calculations and molecular simulations for promising MOF candidates to assess diffusion and adsorption isotherms.

Main Results:

• Simulated CO2 and N2 adsorption in the largest reported dataset of MOFs (~500 structures).
• Identified two stable MOFs with predicted high CO2/N2 selectivity and no diffusion limitations.
• These MOFs are suitable for CO2 capture from dry air and flue gas mixtures.

Conclusions:

• The charge equilibration method is efficient for large-scale MOF screening for gas adsorption.
• Specific MOFs show exceptional potential for selective CO2 capture, addressing critical environmental challenges.
• Computational screening accelerates the discovery of advanced materials for carbon capture technologies.