A Highly Connected Trinuclear Cluster Based Metal–Organic\nFramework for Efficient Separation of C₂H₂/C₂H₄ and C₂H₂/CO₂

Abstract

One\nof the barriers for efficient gas separation is the trade-off between\nthe selectivity and adsorption capacity. To address this issue, we\nsynthesized an anionic trinuclear Co^II based 3D MOF (<b>NbU-8</b>), which is characterized by an ultramicroporous building\nunit (UBU) and Lewis basic binding sites on the pore surfaces. Remarkably,\nthe combination of the two strategies can synergistically enhance\nthe C₂H₂ adsorption capacity (182.9 cm³/g at 298 K) and simultaneously achieve a high separation performance\ntoward C₂H₂/C₂H₄ and C₂H₂/CO₂ mixtures. Besides theoretical\ncalculations, the separation efficiencies of C₂H₂/C₂H₄ and C₂H₂/CO₂ are also demonstrated using breakthrough experiments. Density\nfunctional theory calculations have further confirmed the −OH\ngroups and ultramicroporous building units play an important synergistic\neffect in efficiently capturing acetylene molecules.