Efficient calculation of diffusion limitations in metal organic framework materials: a tool for identifying materials...

Area of Science:

• Materials Science
• Computational Chemistry
• Chemical Engineering

Background:

• The vast structural diversity of metal-organic frameworks (MOFs) presents challenges in identifying materials for specific applications.
• Efficiently screening MOFs for targeted properties like gas separation is crucial for materials discovery.

Purpose of the Study:

• To develop and demonstrate an efficient computational approach for evaluating large numbers of MOFs for kinetic gas separations.
• To identify MOFs with significant differences in diffusion coefficients for adsorbed gas species, optimizing separation performance.

Main Methods:

• Utilized a geometric approach to identify key pore structure features influencing molecular diffusion.
• Coupled geometric analysis with efficient molecular modeling to predict Henry's constant and diffusion activation energy for spherical adsorbates.
• Applied the methodology to screen over 500 MOFs and 160 silica zeolites.

Main Results:

• Demonstrated the efficacy of computational models in evaluating MOFs for kinetic separations of light gases.
• Found that many large-pore MOFs are less suitable for kinetic separations, contrary to initial expectations.
• Identified a substantial number of MOFs predicted to exhibit exceptional performance for separating CO2, CH4, and H2.

Conclusions:

• Efficient computational screening is a viable strategy for discovering MOFs with tailored separation properties.
• The study highlights specific MOF structures with high potential for industrial gas separation applications.
• Results guide future materials design and selection for enhanced kinetic separation processes.