Efficient C₂H_n Hydrocarbons and VOC Adsorption and Separation in an MOF with Lewis Basic and Acidic Decorated Active Sites

To help address efficient separation of C2Hn light hydrocarbons and C2H2/CO2 in the chemical industry, the self-assembly via an azolate–carboxylate ligand and Co(II) ion gave rise to a new porous MOF material, [Co(btzip)(H2btzip)]·2DMF·2H2O (1) (H2btzip = 4,6-bis(triazol-1-yl)isophthalic acid). In the MOF, the pores are modified by rich uncoordinated triazolyl Lewis basic N atoms and acidic −COOH groups, which strengthen interactions with C2Hn hydrocarbons and CO2 molecules, leading to high adsorption amounts for C2H2, C2H4, C2H6, and CO2 and remarkable separation efficiency for C2Hn–CH4, CO2–CH4, and C2H2–CO2 mixtures, as confirmed by breakthrough experiments on the realistic gas mixtures. The MOF also reveals outstanding selective adsorption ability for benzene/toluene, methanol/1-propanol, methanol/2-propanol, and 2-propanol/1-propanol isomers. Molecular simulations disclose the different adsorption sites in the MOF for various adsorbates.