Effect of organic substituents on the adsorption of carbon dioxide on a metal–organic framework

Abstract

The adsorption of carbon dioxide on the MOF-5 metal–organic framework and modifications of it obtained by replacing the hydrogen atoms in the organic ligands with electron donor (–CH₃,–OCH₃) or electron acceptor groups (–CN,–NO₂) is investigated using the grand canonical Monte Carlo (GCMC) method and density functional theory (DFT). It is shown that the adsorption of carbon dioxide molecules on the structures of metal–organic frameworks is most likely on Zn₄O clusters, and that the adsorption of carbon dioxide is of a physical nature. The presence of substituents–CH₃,–OCH₃,–CN in metal–organic frameworks increases their capacity to adsorb carbon dioxide, while that of nitro groups (–NO₂) has the opposite effect.