Enhanced isosteric heat, selectivity, and uptake capacity of CO₂adsorption in a metal-organic framework by impregnated metal ions

Abstract

We demonstrate by experimental and theoretical studies that the impregnation of various metal ions such as Li+, Mg2+, Ca2+, Co2+, and Ni2+ in the pores of an anionic MOF, [Zn3(TCPT)2(HCOO)][NH2(CH3)2] (SNU-100′) significantly enhances isosteric heat, selectivity, and uptake capacity of the CO2 adsorption in the MOF. Due to the electrostatic interactions between CO2 and the extra-framework metal ions, the isosteric heats of CO2 adsorption are increased to 37.4–34.5 kJ mol−1 and the adsorption selectivities of CO2 over N2 at room temperature are increased to 40.4–31.0, compared with those (29.3 kJ mol−1 and 25.5, respectively) of the parent MOF (SNU-100′) containing [NH2(CH3)2]+ cations.