Salen–Mg‐doped NH 2 –MIL‐101(Cr) for effective CO 2 adsorption under ambient conditions

A novel metal‐doped metal–organic framework (MOF) was developed by incorporating salen–Mg into NH 2 –MIL‐101(Cr) structure under ambient conditions. The Schiff base complex was successfully prepared by condensing salicylaldehyde with a free amino group and then coordinating metal ions. Such a structure can endow the sample with higher CO 2 adsorption performance. At 0°C and 1 bar, the salen–Mg‐modified sample achieves the maximum adsorption capacity of 2.18 mmol g −1 for CO 2 , which was 5.8% higher than the pristine salen–MOF under the same conditions. Notably, the Freundlich model indicates that the CO 2 adsorption process of all samples conforms to reversible adsorption. However, the correlation coefficients ( R 2 ) of the Mg‐doped sample are lower than that of the pristine sample. Besides, the CO 2 /N 2 adsorption selectivity and isosteric heat also show a similar trend. These results indicate that the salen–Mg can enhance the interaction between the material and CO 2 molecules.