Enhancement of CO2 Adsorption in Magnesium Alkoxide IRMOF-10
2015
Stergiannakos, Taxiarchis | Klontzas, Emmanuel | Tylianakis, Emmanuel | Froudakis, George E.
Ab initio calculations and GCMC simulations were performed in order to study the CO₂ adsorption from Mg modified IRMOF-10. The Mg cations were introduced in the linker of IRMOF-10 by creating Mg alkoxide groups. Accurate MP2 calculations on the Mg alkoxide linker showed that up to 4 CO₂ molecules can simultaneously interact with the Mg atom of the alkoxide group. The average interaction energy ranged from −14.2 to −8.9 kcal·mol–¹ for one to four interacting CO₂. GCMC simulations were also employed using a modified LJ potential in order to predict the excess CO₂ adsorption isotherms at 300 K and up to 40 bar. The predicted isotherms showed a clear enhancement of the CO₂ uptake when one or two Mg alkoxide groups were introduced per linker with respect to the unmodified IRMOF-10. This enhancement was more pronounced at low pressures. At 10 bar, the volumetric capacity became 5 or 7 times larger than in the case of the unmodified IRMOF-10 by introducing 1 or 2 Mg alkoxide groups, respectively. Based on this significant enhancement, we propose the Mg functionalization as a general strategy for improving the CO₂ storage capacity in MOFs and similar materials.
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