A series of MOFs optimized by pore environment engineering strategy for boosting acetylene-trapping performance

Pore environment engineering endows metal–organic frameworks (MOFs) excellent candidates in the industry gas separation, even for the challenging separation of C2H2/CO2. Here, we present two promising strategies in one MOF system by employed organic ligand [1,1′:3′,1″-terphenyl]-4,4′,4″,6′-tetracarboxylic acid (H4TPTA) and Zinc ions for efficiently separating C2H2 from mixed gases. Clipping the pore size through removement of bi-py, the ZnTPTA-2 possesses improved C2H2 capture capacity of 68.5 cm3 g−1. Furthermore, the ZnTPTA-3 with integrated O/N binding sites and size-adapted aperture is obtained by introducing a pore partition agent 1,2,4-triazole. Therefore, the sharply enhanced C2H2 uptake (35.1 cm3 g−1) at 0.1 bar and a higher IAST selectivity of 19.7 for C2H2/CO2 at 1 bar is further realized due to the multiple host–guest interactions for C2H2 over CO2 with ZnTPTA-3 cage structure, which has been verified by a density functional theory (DFT). Meanwhile, cycling dynamic breakthrough experiments show high-purity C2H2 (>99.8 %) capture capacities of ZnTPTA-3 maintains over 1.89 mmol g−1 from a binary mixture of C2H2/CO2. This work exhibits high-efficient C2H2 separation achieved by an optimal pore environment engineering of MOF adsorbents.