Highly porous and chemically stable covalent organic frameworks with designable vertex skeletons for enhanced gas capture

Abstract

Covalent organic frameworks (COFs) represent a class of porous crystalline materials distinguished by their exceptionally high surface areas and well-defined ordered structures. Constructed from organic molecules interconnected through covalent bonds, COFs possess precisely tunable pore sizes, shapes, and functional groups, making them highly versatile candidates for gas capture applications. In this study, two vertex units were designed and incorporated into imine-based COF frameworks to construct highly conjugated structures, achieving exceptional porosity with a BET surface area of up to 1810 m2/g. Moreover, the synthesized COFs demonstrate remarkable chemical stability under extreme acidic and basic conditions. Notably, the resulting TB-COFs exhibit exceptional propane uptake of 197.2 cm3/g and iodine adsorption capacity of 5.6 g/g, positioning them among the top-performing COFs reported to date. These outstanding adsorption performances are attributed primarily to the large accessible surface area and strong affinity between the COF frameworks and iodine molecules.