The modulation of ethane‐selective adsorption performance in series of bimetal PCN‐250 metal–organic frameworks: Impact of metal composition

Abstract The developments of high‐performance adsorbents have attracted ever‐increasing attention in the separation of ethane/ethylene (C 2 H 6 /C 2 H 4 ) mixtures. In this work, a series of ultra‐stable C 2 H 6 ‐selective metal–organic frameworks (MOFs), PCN‐250, and its bimetal version PCN‐250(Fe 2 M 2+ , M 2+ = Ni 2+ , Co 2+ , Zn 2+ , Mn 2+ ), were synthesized to investigate the influence of metal compositions on the C 2 H 6 ‐selective performance. Among the five materials, at 298 K and 100 kPa, PCN‐250(Fe 2 Co) showed the largest C 2 H 6 uptake (6.21 mmol/g) while PCN‐250(Fe 2 Zn) exhibited the highest C 2 H 6 /C 2 H 4 ideal adsorption solution theory (IAST) selectivity (1.70). The molecular simulation revealed that the introduced metal ions have different influences on the atomic partial charge within the framework which varied the framework adsorption affinities toward C 2 H 6 /C 2 H 4 molecules. Moreover, the research on PCN‐250(Fe 2 Zn) suggested that the increased positive partial charge of metal sites together with a decreased charge density of benzene ring (BR) sites from the organic ligands will be beneficial to improve the desired C 2 H 6 selectivity.