Molecular encapsulation of 5, 10, 15, 20-tetrakis (4-methylphenyl) porphyrinato iron (III) chloride (FeTPP) into MIL-101(Cr) for superior CO2/N2 separation performance

The greenhouse effect associated with excessive CO 2 emission has led to a series of environmental issues, thus developing excellent adsorbents for CO 2 capture from flue gas offers a sustainable approach. To combine the merit of multiple functional components, novel FeTPP@MIL-101(Cr) was prepared by incorporation of 5,10,15,20-tetrakis(4-methylphenyl)porphyrinato iron (III) chloride (FeTPP) into MIL-101(Cr) cages via in-situ packaging strategy. The cage-confined FeTPP can both regulate the pore structures of MIL-101(Cr) and provide additional binding sites for CO 2 adsorption. Profiting from extra interactions for CO 2 component and the “sieving effect” for N 2 component induced by incorporation of FeTPP, the discrepancy of isosteric heat for CO 2 and N 2 was largely amplified. Notably, the CO 2 /N 2 selectivity (15/85, v / v ) calculated by ideal adsorbed solution theory (IAST) increased from 17.1 (MIL-101 (Cr)) to 41.8 (FeTPP@MIL-101 (Cr) with FeTPP loading of 4.98 wt%) at 273 K, 100 kPa, which is 2.44 times larger than that of pristine MIL-101 (Cr) and also exceeds most reported adsorbents.