6533b861fe1ef96bd12c4d97
RESEARCH PRODUCT
Mechanism of water adsorption in the large pore form of the gallium-based MIL-53 metal-organic framework
François-xavier CoudertGuillaume OrtizJoël PatarinGuy WeberAlain H. FuchsAnne BoutinAnne BoutinIgor BezverkhyyJean-pierre BellatAnthony BallandrasGérald Chaplaissubject
Phase transitionchemistry.chemical_elementMineralogy02 engineering and technology010402 general chemistry01 natural sciencesAdsorptionPhase (matter)AtomMolecule[CHIM]Chemical SciencesGeneral Materials ScienceGalliumFourier transform infrared spectroscopyComputingMilieux_MISCELLANEOUSGeneral Chemistry[CHIM.MATE]Chemical Sciences/Material chemistry021001 nanoscience & nanotechnologyCondensed Matter Physics0104 chemical sciences[CHIM.THEO]Chemical Sciences/Theoretical and/or physical chemistrychemistryChemical engineeringMechanics of MaterialsMetal-organic framework0210 nano-technologydescription
Abstract Water adsorption in the large pore ( lp_empty ) form of Ga-MIL-53 was studied by TGA, DSC and in situ XRD and FTIR at 298 K. The large pore form can be stabilized at room temperature after activation under vacuum at 553 K. The isotherm of water adsorption in this large pore form (pore dimensions: 1.67 × 1.33 nm) is very similar to that measured on the narrow pore ( np_empty ) form (pore dimensions: 1.97 × 0.76 nm). Such a similarity is rather unusual given that the pore sizes of these two phases are very different. In order to understand the origin of this effect in situ XRD and FTIR measurements were particularly helpful. It was found that the adsorption of even small amount of water (0.05 mol per Ga atom at 0.2 hPa) in the large pore form of Ga-MIL-53 transforms ca. 50% of the solid into a narrow pore int phase, which is assumed to be present as a shell around the lp_empty core. Additional water molecules adsorbed at higher pressures do not interact with the parent lp_empty phase but with the narrow pore int phase. The phase transformations were confirmed by FTIR revealing significant band displacements in the corresponding pressure ranges. Such easy pore shrinking which occurs at very low water pressure (
| year | journal | country | edition | language |
|---|---|---|---|---|
| 2016-03-01 |