Optimizing\nMultivariate Metal–Organic Frameworks\nfor Efficient C₂H₂/CO₂ Separation

Abstract

Adsorptive separation\nof acetylene (C₂H₂)\nfrom carbon dioxide (CO₂) promises a practical way to produce\nhigh-purity C₂H₂ required for industrial applications.\nHowever, challenges exist in the pore environment engineering of porous\nmaterials to recognize two molecules due to their similar molecular\nsizes and physical properties. Herein, we report a strategy to optimize\npore environments of multivariate metal–organic frameworks\n(MOFs) for efficient C₂H₂/CO₂ separation\nby tuning metal components, functionalized linkers, and terminal ligands.\nThe optimized material UPC-200­(Al)-F-BIM, constructed from Al³⁺ clusters, fluorine-functionalized organic linkers, and benzimidazole\nterminal ligands, demonstrated the highest separation efficiency (C₂H₂/CO₂ uptake ratio of 2.6) and highest\nC₂H₂ productivity among UPC-200 systems. Experimental\nand computational studies revealed the contribution of small pore\nsize and polar functional groups on the C₂H₂/CO₂ selectivity and indicated the practical C₂H₂/CO₂ separation of UPC-200­(Al)-F-BIM.