showing 4 related works from this author
Temperature-Induced Structural Transitions in the Gallium-Based MIL-53 Metal–Organic Framework
2013
We report a structural and thermodynamic investigation of the phase behavior of Ga(OH,F)-MIL-53, a gallium-based metal–organic framework (MOF) having the MIL-53 topology containing 0.7 wt % fluorine bonded to the metal. Despite some small structural differences, especially for the hydrated form, the overall physical chemistry behavior of Ga(OH,F)-MIL-53 is very similar to standard fluorine free Ga-MIL-53 material. A combination of in situ X-ray diffraction, in situ Fourier transform infrared spectroscopy, differential scanning calorimetry, and heat capacity measurements allowed us to establish that Ga(OH,F)-MIL-53 under vacuum (i.e., the empty material) exhibits two stable phases: a nonporo…
MIL-53(Al) under reflux in water: Formation of γ-AlO(OH) shell and H2BDC molecules intercalated into the pores
2014
Abstract It is shown that treatment of MIL-53(Al) (Al(OH)BDC·H2O, BDC = 1,4-benzene dicarboxylate) under reflux in water results in a progressive transformation of the solid into a new well crystallized phase. After reflux for 10 h or more the new phase is obtained in a pure form and its XRD pattern was indexed in a monoclinic system with the following cell parameters: a = 19.47 A, b = 8.98 A, c = 6.60 A, β = 107.7°. Characterization of the obtained solid by TGA, FT-IR, NMR, TEM and XRD has revealed that its composition is [0.8Al(OH)BDC·0.2H2BDC] + 0.2γ-AlO(OH). Formation of this material indicates that under reflux in water a partial hydrolysis of the MOF network occurs producing H2BDC mol…
Mechanism of water adsorption in the large pore form of the gallium-based MIL-53 metal-organic framework
2016
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 wa…
Water Adsorption in Flexible Gallium-Based MIL-53 Metal–Organic Framework
2014
Understanding the adsorption of water in metal–organic frameworks (MOF), and particularly in soft porous crystals, is a crucial prerequisite before considering MOFs for industrial applications. We report here a joint experimental and theoretical study on the behavior of a gallium-based breathing MOF, Ga-MIL-53, upon water adsorption. By looking at the energetics and thermodynamics of Ga-MIL-53, we demonstrate why it behaves differently from its sibling Al-MIL-53, showing a different phase at room temperature (a nonporous phase) and the presence of a hydrated narrow-pore structure at gas saturation pressure. Moreover, we present a complete water vapor pressure vs temperature phase diagram of…