Abstract: Based on the mixed ligand strategy, a bromine-functionalized composite material was synthesized by the reaction of 5-bromoisophthalic acid, 4,4'-bipyridine, and zinc nitrate under solvothermal conditions. The material was characterized using X-ray diffraction, X-ray photoelectron spectroscopy, thermogravimetric analysis, and Fourier transform infrared spectroscopy. The results showed that the prepared material exhibited good hydrothermal stability and possessed a microporous structure with a most probable pore diameter of 0.35 nm. Compared to C₂H₂,CH₄,CO,N₂, it exhibited significantly better adsorption capacity for CO₂, enabling effective separation of CO₂ from other gases. At 273 K and 100 kPa, the adsorption capacity of the material for CO₂ was 48.901 cm³/g. Density functional theory calculations further revealed the mechanism of action of -Br on CO₂ and its synergistic effect with hydrogen bonding.

Key words: 5-bromoisophthalic acid, 4,4'-bipyridine, bromine-functionalized, microporous material, carbon dioxide, selective adsorption