Pyrazine-cored covalent organic frameworks for efficient CO2 adsorption and removal of organic dyes

Abstract

The rational introduction of nitrogen heterocycles into a linker of covalent organic frameworks (COFs) can effectively capture CO₂ and remove dyes in sewage. Here, we report the designed synthesis of COF-H1 and COF-H2, starting from integration reactions between a novel tetratopic 2,3,5,6-tetrakis(4-aminophenyl)pyrazine and ditopic aromatic aldehydes. They crystallize as 2D microporous pore structures with high stability in different environments, exhibiting good CO₂ uptake capacities of 56.8 and 66.2 mg g⁻¹ at 273 K, respectively. COF-H1 and COF-H2 exhibit efficient adsorption performances for rhodamine B, methylene blue, Congo red and gentian violet, especially reaching the adsorption equilibrium for Congo red in 5 minutes together with an adsorption capacity of 470.3 and 362.9 mg g⁻¹, respectively.