3D qtz-Topology COFs With Bicarbazole-Centered Nodes for High-Performance Adsorption of C6 VOCs.

The periodic structure featuring ordered open nanopores and high porosity endows covalent organic frameworks (COFs), especially three-dimensional (3D) COFs, with remarkable potential for various applications. However, the precise construction of highly crystalline and functionalized 3D COFs remains a major challenge, due to the limited availability of suitable 3D building blocks and the inherent complexity of synthesis. Herein, by selecting a unique 3D precursor containing a bicarbazole motif, we successfully synthesized two 3D COFs (3D-BCZ-COF-1 and 3D-BCZ-COF-2) featuring threefold interpenetrated qtz topology. Notably, both COFs exhibit inherent porosity, high crystallinity, and large BET surface areas (2073 m2 g-1 for 3D-BCZ-COF-1, 1989 m2 g-1 for 3D-BCZ-COF-2). Benefiting from their excellent crystallinity and bicarbazole-derived pore environments, both COFs demonstrate highly efficient adsorption of C6 volatile organic compounds (VOCs). In particular, 3D-BCZ-COF-1 achieves adsorption capacities of 910.2 mg g-1 for benzene, 796.2 mg g-1 for cyclohexane, and 684.0 mg g-1 for n-hexane, outperforming most reported porous materials. This work indicates that the precise fabrication of highly crystalline 3D COFs with functional units offers a promising platform for addressing VOCs challenges.