Computational Screening of Alkali, Alkaline Earth, and Transition Metals Alkoxide-Functionalized Metal–Organic Frameworks for CO2 Capture

Abstract

Carbon dioxide capture from flue gas and natural gas are important industrial processes. As an energy-efficient alternative of the traditional cryogenic method, equilibrium-based CO2 capture by solid porous materials, that is, metal–organic frameworks (MOFs), has shown great potential for CO2 separation. In this work, the CO2 adsorption ability of a UiO-type MOFs, UiO-67, is dramatically tuned by incorporating various metal ions, including alkali metals (Li, Na, and K), alkaline earth metals (Be, Mg, and Ca), and first-row transition metals (Sc to Cu), into the framework. Specifically, the binding energies of CO2 on Be, Ca, Ti, V, Mn, and Fe alkoxide-functionalized ligands exceed that of Li alkoxide-functionalized ligand. Grand canonical Monte Carlo simulations show clear CO2 adsorption enhancements at 298 K and pressure up to 5000 kPa for the functionalized MOF, especially at a low pressure range. Ti alkoxide-functionalized MOFs show the highest uptake amount of CO2 at low pressures. Additionally, the ex...