A Highly Connected Trinuclear Cluster Based Metal-Organic Framework for Efficient Separation of C₂H₂/C₂H₄ and...

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