An ethane-trapping Zn (II) cluster-based metal-organic framework with suitable pockets for efficient ethane/ethylene separation

Efficient separation of ethane (C 2 H 6 ) from ethylene (C 2 H 4 ) using C 2 H 6 -selective adsorbents is more efficient but challenging due to their similar physical and chemical properties. Herein, we report a Zn (II) cluster-based metal-organic framework, Zn 4 O(NTB) 2 , with suitable cavity pockets and favorable adsorption sites for the reverse capture of C 2 H 6 from C 2 H 6 /C 2 H 4 mixtures. Both high C 2 H 6 uptake (2.83 mmol g −1 ) and C 2 H 6 /C 2 H 4 selectivity (2.06) at 273 K and 1 bar was achieved, outperforming many top-ranking C 2 H 6 -selective adsorbents. Moreover, dispersion-corrected density functional theory (DFT) and grand canonical Monte Carlo (GCMC) simulation revealed that C H···O and C H···π interactions are formed with C 2 H 6 in the suitable pockets with saturated Zn clusters and nonpolar pore surfaces. Dynamic breakthrough experiments demonstrated its practical separation performances with various gas-mixture compositions and those containing water vapor.