| Autor: |
Cavallo, Margherita, Atzori, Cesare, Signorile, Matteo, Costantino, Ferdinando, Venturi, Diletta Morelli, Koutsianos, Athanasios, Lomachenko, Kirill A., Calucci, Lucia, Martini, Francesca, Giovanelli, Andrea, Geppi, Marco, Crocellà, Valentina, Taddei, Marco |
| Zdroj: |
Journal of Materials Chemistry A; 3/21/2023, Vol. 11 Issue 11, p5568-5583, 16p |
| Abstrakt: |
Adsorbents able to uptake large amounts of gases within a narrow range of pressure, i.e., phase-change adsorbents, are emerging as highly interesting systems to achieve excellent gas separation performances with little energy input for regeneration. A recently discovered phase-change metal–organic framework (MOF) adsorbent is F4_MIL-140A(Ce), based on CeIV and tetrafluoroterephthalate. This MOF displays a non-hysteretic step-shaped CO2 adsorption isotherm, reaching saturation in conditions of temperature and pressure compatible with real life application in post-combustion carbon capture, biogas upgrading and acetylene purification. Such peculiar behaviour is responsible for the exceptional CO2/N2 selectivity and reverse CO2/C2H2 selectivity of F4_MIL-140A(Ce). Here, we combine data obtained from a wide pool of characterisation techniques – namely gas sorption analysis, in situ infrared spectroscopy, in situ powder X-ray diffraction, in situ X-ray absorption spectroscopy, multinuclear solid state nuclear magnetic resonance spectroscopy and adsorption microcalorimetry – with periodic density functional theory simulations to provide evidence for the existence of a unique cooperative CO2 adsorption mechanism in F4_MIL-140A(Ce). Such mechanism involves the concerted rotation of perfluorinated aromatic rings when a threshold partial pressure of CO2 is reached, opening the gate towards an adsorption site where CO2 interacts with both open metal sites and the fluorine atoms of the linker. [ABSTRACT FROM AUTHOR] |
| Databáze: |
Complementary Index |
| Externí odkaz: |
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