Amino-functionalized Cu-IPA(-NH₂) MOFs for highly selective SF₆/N₂ separation via polar interactions

Sulfur hexafluoride (SF 6 ), a critical insulating gas with an exceptionally high global warming potential (~23,500 × CO 2 ), demands energy-efficient separation technologies due to its prevalent use in nitrogen-blended industrial mixtures. To address this challenge, we present the rational design of Cu-IPA(-NH 2 ), an amine-functionalized kagome metal-organic framework synthesized via solvothermal methods. Comprehensive structural characterization (XRD, SEM) confirms its highly crystalline nature and hierarchical pore architecture featuring complementary adsorption sites. The material exhibits exceptional SF 6 /N 2 selectivity with a record SF 6 uptake capacity of 46.3 cm 3 g ‐1 at 1 bar (vs. 1.8 cm 3 g ‐1 for N 2 ), outperforming most reported adsorbents. Dynamic breakthrough tests reveal a notable SF 6 /N 2 separation selectivity with a 12 min g-1 retention time difference, demonstrating practical feasibility for flow-through processes. Mechanistic studies through density functional theory (DFT) calculations unveil that the exceptional selectivity originates from cooperative host-guest interactions: SF 6 shows a substantially stronger binding energy (-58.39 kJ mol ‐1 ) compared to N 2 (-2.44 kJ mol ‐1 ), facilitated by multipoint contacts with amine groups and confined pore windows. This work advances the development of pore-environment-engineered MOFs for high-value gas separations while providing fundamental insights into the design of cooperative adsorption sites for greenhouse gas capture.