Boosting C2H6/C2H4 separation in scalable metal‐organic frameworks through pore engineering

The development of ethane (C2H6)‐selective adsorbents for ethylene (C2H4) purification, although challenging, is of prime industrial importance. Pillared‐layer metal‐organic frameworks (MOFs) possess facilely tunable pore structure and functionality, which means they have excellent potential for high‐performance C2H6/C2H4 separation applications. Herein, we report a family of isostructural pillared‐layer MOFs with various metal centers M and co‐ligands L, M2(D‐cam)4L2 (denoted M‐cam‐L; M = Cu, Co, Ni; L = pyz, apyz, dabco), with a variety of pore surface properties. All of the M‐cam‐L materials exhibit preferential adsorption for C2H6 over C2H4. In particular, Ni‐cam‐pyz exhibits the highest C2H6 capture capacity (68.75 cm3 g−1 at 1 bar and 298 K), Cu‐cam‐dabco possesses the greatest C2H6/C2H4 adsorption selectivity (2.3), and the lowest isosteric heat of adsorption is demonstrated for Cu‐cam‐pyz (20.1 kJ mol−1). Dynamic column breakthrough experiments also confirmed the excellent separation performance of M‐cam‐pyz and M‐cam‐dabco materials. The synthesis route of the M‐cam‐L materials is easily scaled‐up under laboratory conditions, and hence this class of MOFs is promising for practical C2H4 purification.