Inverse CO2/C2H2 separation in a pillared-layer framework featuring a chlorine-modified channel by quadrupole-moment sieving

Selective isolation of CO2 from C2H2 using CO2 -selective adsorbent is a huge challenge due to their analogous physical properties as well as molecular sizes and shapes. In this work, utilizing an effective strategy of embedding electronegative Cl atoms in pore surface of MOF, a 3D pillared-layer ultramicroporous MOF, [Zn(atz) (BDC-Cl4)(0.5)](n), (1) (Hatz = 3-amino-1,2,4-triazole; BDC-Cl4 = tetrachlomterephthalic acid) for inverse CO2/C2H2 separation was successfully constructed. This MOF show a CO2/C2H2 (V:V = 1:1) adsorption selectivity of 2.4 at 285 K and 100 kPa. Computational studies further uncover CO2 recognition mechanism is due to the matching of the unique pore environment decorating by Cl atoms with quadrupole moment of CO2.

Automated summary

By embedding Cl atoms in MOF, a highly CO2-selective ultramicroporous MOF was constructed for successful inverse CO2/C2H2 separation. Computational studies revealed that the unique pore environment decorated with Cl atoms matches the quadrupole moment of CO2, leading to CO2 recognition mechanism.