Boosting molecular recognition of acetylene in UiO-66 framework through pore environment functionalization

Abstract

The potential of metal–organic frameworks (MOFs) for application in gas separation processes has been widely recognized. Nonetheless, due to their structural instability and high cost, few MOFs have been utilized in the industry. Among them, UiO-66 is one of the most promising materials which displays good structural stability and its preparation is considered economical. Notably, it also provides a valuable platform for the construction of other robust MOFs for various applications. Herein, trifluoromethyl ligands were introduced into the UiO-66 framework to optimize pore environment also to improve its C2H2 recognition ability. Single component adsorption and the corresponding IAST calculation confirmed that compared to UiO-66, UiO-66-(CF3)2 exhibited 2 ~ 3 times higher selectivity for C2H2/C2H4 and C2H2/CO2 separation. Enhanced selectivity resulted in a significantly improved C2H4 separation productivity (56 compared to 36 cm3/cm3) and a reduction in the co-adsorption time. Importantly, the modified UiO-66 framework could be prepared using a simple method and inherited a highly stable structure and good cycling performance of the original material.