A Microporous Hydrogen‐Bonded Organic Framework with Open Pyrene Sites Isolated by Hydrogen‐Bonded Helical Chains for Efficient Separation of Xenon and Krypton

Abstract

Achieving efficient xenon/krypton (Xe/Kr) separation in emerging hydrogen‐bonded organic frameworks (HOFs) is highly challenging because of the lack of gas‐binding sites on their pore surfaces. Herein, we report the first microporous HOF (HOF‐FJU‐168) based on hydrogen‐bonded helical chains, which prevent self‐aggregation of the pyrene core, thereby preserving open pyrene sites on the pore surfaces. Its activated form, HOF‐FJU‐168a is capable of separating Xe/Kr under ambient conditions while achieving an excellent balance between adsorption capacity and selectivity. At 296 K and 1 bar, the Xe adsorption capacity of HOF‐FJU‐168a reached 78.31 cm³/g, with an Xe/Kr IAST selectivity of 22.0; both values surpass those of currently known top‐performing HOFs. Breakthrough experiments confirmed its superior separation performance with a separation factor of 8.6 and a yield of high‐purity Kr (> 99.5%) of 184 mL/g. Furthermore HOF‐FJU‐168 exhibits excellent thermal and chemical stability, as well as renewability. Single‐crystal X‐ray diffraction and molecular modeling revealed that the unique electrostatic surface potential around the open pyrene sites creates a micro‐electric field, exerting a stronger polarizing effect on Xe than on Kr, thereby enhancing host‐Xe interactions.