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

Abstract

Metal–organic frameworks (MOFs) are promising materials for the efficient capture of CO₂. Nevertheless, the weak interaction between the MOFs and CO₂ molecules impede the equilibrium between the adsorption capacity and selectivity of CO₂. Furthermore, the lower CO₂ adsorption performance, lower selectivity, and lower synthesis yield of MOFs than those of other adsorbents and their inhomogeneity are major drawbacks. Herein, to improve the conventional Mg-based MOFs adsorbents, pore length of the Mg-MOF materials was shortened, while obtaining a more dispersible particle structure. By utilizing the macromolecular amine structure, amine molecules were vapor-deposited into the MOF pores. The CO₂ adsorption capacity was demonstrated to be as high as 203 mL g⁻¹ (273 K, 1 bar), and the IAST adsorption selectivity was as high as 304. GCMC and DFT simulations showed that the sequential construction of short-dispersed pores and the introduction of pore-matching amine structures improved the adsorption performance and selectivity of CO₂. This work offers insights into for the design and controllable preparation principles of the adsorption and screening of bi-functional Mg-based MOFs-based carbon capture materials and provides a fundamental basis for obtaining MOF-based carbon capture materials with improved efficiency.