Enhanced Selective CO2 Capture upon Incorporation of Dimethylformamide in the Cobalt Metal–Organic Framework [Co3(OH)2(btca)2]

As society’s demand for energy increases and more CO2 emissions are produced, it becomes imperative to selectively capture CO2 and decrease the amount emitted to the atmosphere. Here, we present a flexible and porous metal–organic framework (MOF), [Co3(OH)2(btca)2] (1) (where btca = benzotriazole-5-carboxylic acid), which exhibits excellent CO2 uptake (223.7 mg g–1 at 273 K and 104.7 mg g–1 at 298 K) and better selectivity for CO2/N2 (46.3 at 273 K) . During the sample preparation or after an exchange process, compound 1 could trap guest molecules [dimethylformamide (DMF)] into the channels and then yield an isostructural product [Co3(OH)2(btca)2]·0.5DMF (1·0.5DMF). 1·0.5DMF hardly adsorbs N2, O2, and H2 but favorably captures CO2 in the entire pressure range measured, responded by highly selective CO2/N2 gas separation with Henry’s law selectivity of 79.6.