Identification of Adsorption Sites for CO<sub>2</sub> in a Series of Rare-Earth and Zr-Based Metal-Organic Frameworks.

Abstract

The adsorption of CO2${{\rm{CO}}_2 }$ in MOF-808, NU-1000 and a series of rare-earth CU-10 analogues has been studied with first principles DFT and classical Monte-Carlo methods. DFT calculations describe the interaction of CO2${{\rm{CO}}_2 }$ with the different metal-organic frameworks (MOFs) as physisorption, but where we can distinguish several adsorption sites in the vicinity of the metal nodes. Beyond the identification of adsorption sites, the MOFs were synthesized, activated, and characterized to evaluate their experimental N2${{\rm{N}}_2 }$ and CO2${{\rm{CO}}_2 }$ adsorption capacity. Classical Grand Canonical Monte-Carlo (GCMC) simulations for the adsorption of CO2${{\rm{CO}}_2 }$ are in very good agreement with DFT results for identifying the most favored adsorption sites in the MOFs. In contrast, a rather mixed agreement between GCMC simulations and experimental results is found for the estimation of adsorption capacity of several MOFs studied toward N2${{\rm{N}}_2 }$ and CO2${{\rm{CO}}_2 }$ .