Competitive Coadsorption of CO2 with H2O, NH3, SO2, NO, NO2, N2, O2, and CH4 in M-MOF-74 (M = Mg, Co, Ni): The Role of Hydrogen Bonding

By Kui‐Thong Tan, S. Zuluaga, Qihan Gong, Yuzhi Gao, Nour Nijem, Jing Li, T. Thonhauser, Y. Chabal. 2015

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The importance of coadsorption for applications of porous materials in gas separation has motivated fundamental studies, which have initially focused on the comparison of the binding energies of different gas molecules in the pores (i.e., energetics) and their overall transport. By examining the competitive coadsorption of several small molecules in M-MOF-74 (M = Mg, Co, Ni) with in situ infrared spectroscopy and ab initio simulations, we find that the binding energy at the most favorable (metal) site is not a sufficient indicator for prediction of molecular adsorption and stability in MOFs. Instead, the occupation of the open metal sites is governed by kinetics, whereby the interaction of the guest molecules with the MOF organic linkers controls the reaction barrier for molecular exchange. Specifically, the displacement of CO2 adsorbed at the metal center by other molecules such as H2O, NH3, SO2, NO, NO2, N2, O2, and CH4 is mainly observed for H2O and NH3, even though SO2, NO, and NO2 have higher binding...

Subfields: Inorganic Chemistry, Materials Chemistry

View Paper: https://www.semanticscholar.org/paper/c67d1bc351519d4d99ccc4f14d6d471a8a6c1ca6