Biomimetic Hydrophobic-Polar Metal-Organic Frameworks for Record-Breaking Separation and Capture of Xenon and Krypton.

The separation and capture of xenon (Xe) and krypton (Kr) pose critical industrial and environmental challenges. We report two isostructural MOFs (NKMOF-8-Br and NKMOF-8-Me) with ultra-micropores (∼6 Å) integrating bromine/methyl and cyano groups, creating biomimetic hydrophobic-polar microenvironments for efficient Xe/Kr separation and nuclear off-gas capture. These MOFs exhibit record low-pressure Xe uptake and Xe packing density. Breakthrough tests under two industrial scenarios-air-separation byproduct purification and trace gas capture-demonstrate unprecedented Kr productivity (12.26 mmol g-1) and Xe/Kr capture capacity (Xe: 32.13 mmol kg-1; Kr: 9.35 mmol kg-1), with retained performance after 500 kGy β-irradiation. Single-crystal X-ray diffraction confirms gas molecules preferentially occupying channel centers, stabilized by hydrophobic van der Waals interactions and cyano polarization effects, while theoretical simulations establish a clear structure-property relationship. These results highlight NKMOF-8-Br and NKMOF-8-Me as leading candidates for energy-efficient noble gas separation and nuclear waste management, and demonstrate a generalizable strategy for engineering adsorption through hydrophobic-polar synergy.