A highly stable yttrium-based metal-organic framework with two-fold interpenetrated and cage-like pore structure for one-step purification of ethylene from ethylene/ethane mixture

Abstract

One-step purification of ethylene (C2H4) from C2H6/C2H4 mixture is of paramount significance, but it is still challenging for C2H6-selective adsorbents to balance the trade-off between C2H6 adsorption capacity and C2H6/C2H4 uptake ratio or selectivity. Herein, we reported a stable yttrium-based MOF, Y-TATB, constructed with two distinct Y(III) clusters, Y3 and Y9, and ligand 4,4′,4″-(1,3,5-triazine-2,4,6-triyl)benzoic acid (H3TATB). Y-TATB featured a two-fold interpenetrated structure, of which a cage-like pore formed out for better C2H6 recognition and storage. Y-TATB exhibited both high C2H6 uptake and C2H6/C2H4 uptake ratio of 4.33 mmol/g and 1.45 at 298 K and 1 bar, exceeding most C2H6-selective MOFs. GCMC simulations demonstrated that the N-rich and nonpolar pore surfaces of Y-TATB generated multiple C-H···π interactions between the framework and C2H6, rendering the discrimination between C2H6 and C2H4. Dynamic breakthrough experiments further validated its feasibility in one-step production of high-purity C2H4 (>99.95%), endowing Y-TATB a promising candidate for practical implementation in industry.