Metal Node Guided Pore Engineering in Carborane-Based MOFs for Efficient C₂H₂/CO₂ and C₂H₂/C₂H₄ Separations.

Area of Science:

• Materials Science
• Chemical Engineering
• Separation Science

Background:

• Efficient separation of acetylene (C2H2) from CO2 and C2H4 is crucial for producing high-purity C2H2 and C2H4.
• Existing methods face challenges balancing adsorption capacity and selectivity.

Purpose of the Study:

• To develop a node-guided pore engineering strategy in carborane-based metal-organic frameworks (MOFs).
• To create a partitioned dual cage system for enhanced gas separation.
• To investigate the separation performance and mechanism of the engineered MOF.

Main Methods:

• Synthesis of carborane-based metal-organic frameworks (MOFs) with engineered pore structures (Co-CB-HPBTA).
• Gas adsorption and selectivity measurements for C2H2/CO2 and C2H2/C2H4 mixtures.
• Breakthrough experiments to evaluate real-world separation performance.
• Density Functional Theory (DFT) calculations and in situ single-crystal X-ray diffraction for mechanism elucidation.

Main Results:

• Co-CB-HPBTA exhibits a high C2H2 adsorption capacity (103.2 cm3/g) and superior selectivity for C2H2/CO2 (10.6) and C2H2/C2H4 (13.3).
• Breakthrough experiments confirmed excellent separation performance, yielding high-purity C2H2 and C2H4.
• The material demonstrated remarkable cyclic stability and humidity tolerance.
• DFT calculations and X-ray diffraction revealed enhanced binding interactions within partitioned cages, explaining the high selectivity.

Conclusions:

• The node-guided pore engineering strategy effectively creates a partitioned dual cage system in MOFs for superior gas separation.
• Co-CB-HPBTA is a promising material for the efficient and selective separation of acetylene from CO2 and C2H4.
• The study provides insights into the mechanism of enhanced gas binding and separation in engineered MOFs.