Novel amine-functionalized Mg-MOF CO2 adsorbents with a bi-functional adsorption-screening

Abstract

Metal-organic frameworks (MOFs), an auspicious material for the efficient capture of CO₂, nevertheless impede the equilibrium between adsorption capacity and selectivity of CO₂, attributable to the feeble interaction between the MOFs and CO₂ molecules. The lower CO2 adsorption performance of MOFs with respect to other adsorbents, their lower selectivity, lower synthesis yield and inhomogeneity are major drawbacks. Here, in order to improve the conventional Mg-based MOFs adsorbents, the pore length of Mg-MOF materials was shortened, while obtaining a more independent particle structure. By utilizing the macromolecular amine structure, amine molecules were vapor-deposited into the MOFs pores. The CO2 adsorption capacity was demonstrated to be as high as 203 mL/g (273 K, 1 bar), and the IAST adsorption selectivity was as high as 304. GCMC and DFT simulations show that the sequential construction of short dispersed pores and the introduction of pore matching amine structures are conclusive to improve the adsorption performance and selectivity of CO₂ and leads the way to the design and controllable preparation principles of adsorption and screening bi-functional Mg-based MOFs-based carbon capture materials, while providing a fundamental basis for an improved efficiency of MOF-based carbon capture materials.