Enhancement of CO2 Adsorption in Magnesium Alkoxide IRMOF-10

• Published in: Journal of physical chemistry. C 2015-09, Vol.119 (38), p.22001-22007
• Main Authors: Stergiannakos, Taxiarchis, Klontzas, Emmanuel, Tylianakis, Emmanuel, Froudakis, George E
• Format: Article
• Language: English
• ISSN: 1932-7447; 1932-7455
• DOI: 10.1021/acs.jpcc.5b05294

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.