C2-phenyl-substituted benzimidazolium-based covalent organic framework as efficient catalyst for CO 2 conversion without solvents, metals, and cocatalysts

Covalent organic frameworks (COFs) are a potential platform for carbon dioxide (CO 2 ) conversion owing to their periodic permanent porosity, adjustable structure, and chemical stability. For good catalytic performance in CO 2 conversion, collaborative multifunctions should be strategically integrated into the catalytic system design and construction. In this study, a four-in-one high-efficiency catalyst was synthesized and tested for CO 2 cycloaddition to form cyclic carbonate. The obtained Tp-MPB-Br-COF had a high nitrogen content, which enhanced its CO 2 affinity through substantial Lewis acid-base or dipole-quadrupole interactions; moreover, the acid (protons transferring from oxygen (–OH) to nitrogen (–NH)), hydrogen bond donor (hydroxyl group), and Br − (nucleophile group) served as three active sites, further improving the catalyst activity. These results provide a basis for designing efficient and stable CO 2 -conversion catalysts.