Integration of [Cr3O(HCOO)6(H2O)3]NO3 into MIL-101(Cr) for enhanced separation of CO2/N2 mixture

Developing novel adsorbents for CO 2 capture and separation offers an efficient approach to relieving global environmental problems. To promote CO 2 capture from flue gas, novel Cr 3 O@MIL-101(Cr) composites was synthesized through packing [Cr 3 O(HCOO) 6 (H 2 O) 3 ]NO 3 into MIL-101(Cr) cages. The resultant composite Cr 3 O@MIL-101(Cr) presents higher CO 2 uptakes at lower pressure ranges, benefiting from the increased content of unsaturated Cr(III) ions and micropores relative to MIL-101(Cr). Meanwhile, IAST selectivity for CO 2 /N 2 mixture reached 50.2 under standard temperature and pressure, outperforming most of the reported materials. Further GCMC simulations reveal that the synergistic effect of [Cr 3 O(HCOO) 6 (H 2 O) 3 ] + , NO 3 − and MIL-101 (Cr) could effectively facilitate the interactions with CO 2 molecules and hinder N 2 molecules from approaching the optimal adsorption sites. Thus the [Cr 3 O(HCOO) 6 (H 2 O) 3 ]NO 3 encapsulated MIL-101(Cr) can be recommended as a promising adsorbent for superior CO 2 /N 2 separation.