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First principles Monte Carlo simulations of unary and binary adsorption: CO₂, N₂, and H₂O in Mg-MOF-74
- Fetisov, Evgenii O., Shah, Mansi S., Long, Jeffrey R., Tsapatsis, Michael, Siepmann, J. Ilja
- Chemical communications 2018 v.54 no.77 pp. 10816-10819
- Monte Carlo method, adsorption, carbon dioxide, chemical reactions, coordination compounds, nitrogen, prediction
- Dative bonding of adsorbate molecules onto coordinatively-unsaturated metal sites in metal–organic frameworks can lead to unique adsorption selectivities. However, the distortion of the electron density during dative bonding poses a challenge for force-field-based simulations. Here, we report first principles Monte Carlo simulations with the PBE-D3 functional for the adsorption of CO₂, N₂, and H₂O in Mg-MOF-74, and obtain accurate predictions of the unary isotherms without any of the adjustments or fitting often required for systems with strong adsorption sites. Simulations of binary CO₂/N₂ and H₂O/CO₂ mixtures yield selectivities of 200 and 160, respectively, and indicate that predictions from ideal adsorbed solution theory need to be viewed with caution.