A highly porous acylamide decorated MOF-505 analogue exhibiting high and selective CO2 gas uptake capability

Abstract

Porous metal–organic frameworks (MOFs) constructed from organic linkers and metal ions/clusters can provide special pore environments for selective CO₂ capture. In this work, we designed and synthesized a highly porous acylamide-functionalized MOF (HNUST-7) from a nanosized linear diisophthalate ligand with linking acylamide groups and Cu(II)-paddlewheel clusters. Structural analysis shows that HNUST-7 possesses a (4,4)-connected NbO-type 3D open framework incorporating two different types of metal–organic cages. After activation, HNUST-7 displays a high BET surface area of 2804 m² g⁻¹ and large CO₂ uptakes of 26.1 and 19.4 mmol g⁻¹ under 30 bar at 273 and 298 K, respectively. In addition, with the optimized pores and functional sites (open copper sites and Lewis basic acylamide groups) integrated within the framework, HNUST-7 exhibits highly selective adsorption of CO₂ over CH₄ and N₂ under ambient conditions, which have been verified by both single compound gas sorption measurements and dynamic column breakthrough experiments.