Double‐Walled Covalent Organic Frameworks with High Stability

Abstract

AbstractDouble‐walled covalent organic frameworks, consisting of two same building blocks parallel to each other forming ladder‐shape linkers, could enhance the stability of the frameworks and increase the density of functional sites, thus making them suitable for various applications. In this study, two double‐walled covalent organic frameworks, namely DW‐COF‐1 and DW‐COF‐2, were successfully synthesized via imine condensation. The resulting DW‐COFs exhibited a honeycomb topology, high crystallinity and stability. Particularly, DW‐COF‐2 showed excellent resistance toward boiling water, strong acid, and strong base, due to its double‐walled structure, which limits the exposure of labile imine bonds to external chemical environments. The DW‐COFs showed high porosity near 900 m2/g, making them suitable for gas storage/separation. The selective gas adsorption experiments showed that at 273 K and 1 atm pressure, DW‐COF‐1 and DW‐COF‐2 exhibited a good IAST selectivity towards CO2/N2 (15/85) adsorption, with selectivity values of 121.3 and 56.4 for CO2 over N2, respectively.