Molecular Simulation Evaluation on C₂H₂/CO₂ Selective Adsorption in CoV-tcb Pacs-Type Metal-Organic Frameworks

Area of Science:

• Materials Science
• Chemical Engineering
• Computational Chemistry

Background:

• Separating acetylene (C₂H₂) from carbon dioxide (CO₂) is crucial for industrial processes.
• Existing metal-organic frameworks (MOFs) like CoV-bdc pacs-type MOFs, designed with pore space partition (PSP), show limitations in C₂H₂/CO₂ selectivity.
• The microscopic mechanisms behind MOF selectivity for C₂H₂/CO₂ require further investigation.

Purpose of the Study:

• To investigate the microscopic mechanism of enhanced C₂H₂/CO₂ separation selectivity in CoV-tcb pacs-type MOFs.
• To evaluate the effectiveness of the combined bioisosteric (BIS) and pore space partition (PSP) strategy in designing MOFs for gas separation.
• To computationally analyze the adsorption behavior of C₂H₂ and CO₂ in CoV-tcb and CoV-bdc pacs-type MOFs.

Main Methods:

• Employed grand canonical Monte Carlo (GCMC) simulations to calculate the C₂H₂/CO₂ separation selectivity.
• Analyzed gas adsorption density distributions within the pore structures of CoV-tcb and CoV-bdc pacs-type MOFs.
• Utilized the bioisosteric (BIS) strategy in conjunction with pore space partition (PSP) for MOF design.

Main Results:

• CoV-tcb pacs-type MOFs, incorporating the BIS-PSP strategy, demonstrated significantly higher C₂H₂/CO₂ selectivity compared to CoV-bdc pacs-type MOFs.
• CoV-tcb-tpt exhibited a C₂H₂/CO₂ selectivity of 6.72 (99/1 ratio).
• Density distributions revealed that the BIS strategy prevented gas absorption in the o-cages of CoV-tcb pacs-type MOFs, unlike in CoV-bdc pacs-type MOFs.

Conclusions:

• The combined BIS-PSP strategy effectively enhances C₂H₂/CO₂ selectivity in MOFs by controlling gas adsorption sites.
• Molecular simulations confirm the improved performance of CoV-tcb pacs-type MOFs due to the BIS strategy.
• This study provides a validated approach for designing novel MOFs with superior gas separation capabilities.