Effect of the doping agent nature on the characteristic and catalytic properties of aerogel zirconia catalysts doped with sulfate groups or heteropolytungstic acid

Chakhari, Samir; Younes, Mohamed Kadri; Rives, Alain; Ghorbel, Abdelhamid

doi:10.1016/j.materresbull.2015.07.012

Cited by 10 publications

(4 citation statements)

References 60 publications

(55 reference statements)

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“…3). The morphology was similar to those prepared from "alkoxide hydrolysis" 39 and "epoxide adding" 40 methods, in which the aerogel was composed of porous networks. The insert image in Fig.…”

Section: Resultsmentioning

confidence: 60%

“…6. 39 In the third stage, there was about 5% (xerogel) and 1% (aerogel) weight loss from 450 to 700 C, attributing to the complete decomposition of LAA and further crystalline phase transferring of ZrO 2 . The weight loss of aerogels was much less than that of its corresponding xerogel samples, which was consistent with the former FTIR and XPS results.…”

Section: Resultsmentioning

confidence: 93%

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The investigation of an organic acid assisted sol–gel method for preparing monolithic zirconia aerogels

Wang

Shi

et al. 2018

RSC Adv.

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Section: Resultsmentioning

confidence: 60%

Section: Resultsmentioning

confidence: 93%

The investigation of an organic acid assisted sol–gel method for preparing monolithic zirconia aerogels

Wang

Shi

et al. 2018

RSC Adv.

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“…From the spectra shown in Figure 3B it is evident that for all sulfated UiO-66 samples no significant changes in the spectral profiles can be observed. If very small ZrO2 crystallites (<1 nm) were present they should produce intense signals around 210-230 nm, which are typical of the octa-coordinated zirconium in the oxide due to O 2-Zr 4+ charge transfer transitions and a broad peak at 280-300 nm due to defects such as oxygen vacancies [41,42]. An UV-VIS DRS analysis of a sulfated zirconia sample (Figure S6a) clearly shows how this solid has intense signals below 228 nm, added to a quite strong and broad signal extended from 250 up to 400 nm.…”

Section: Interaction Of Sox Species With the Structure Of The Mofmentioning

confidence: 99%

Direct sulfation of a Zr-based metal-organic framework to attain strong acid catalysts

Fernández-Morales

Lozano

Castillejos

et al. 2019

Microporous and Mesoporous Materials

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The application of Metal-Organic Frameworks (MOFs) in gas phase heterogeneous catalysis is still not widely spread because of their limited stability under reaction conditions. Obtaining stable acidic MOFs to be used in reactions that demand strong acid sites remains a challenge up to the present time. In this work, it is shown that nanocrystals of Zirconium MOF UiO-66 can be conveniently and easily functionalized through a simple one-pot synthetic approach, i.e. the direct treatment of UiO-66 with ammonium sulfate followed by an adequate thermal treatment, giving rise to a highly acidic and thermally stable material (named as S-UiO-66). This material can act as catalyst in the gas phase isobutene dimerization demonstrating high catalytic activity at moderate temperatures while maintaining the structural integrity of the MOF after several catalytic evaluations and/or after reuse cycles. The S-UiO-66 material represents a novel alternative in the search of robust MOF-based catalysts to be applied in gas phase heterogeneous catalytic reactions that demand strong acid sites.

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“…11 Among them, the ZrO 2 aerogel is interesting and important because of its high melting point, lowest intrinsic thermal conductivity among metal oxides, and both acid and base active centers. 12 Later, ZrO 2 aerogels were found to be efficient in catalyzing various chemical reactions, including hydrogenation, 13 dehydrogenation, 14 isomerization, 15 and esterification. 16 Hrubesh et al theoretically predicted that ZrO 2 aerogels would be the best inorganic aerogels for uses at the lowest achievable thermal conductivity.…”

Section: Introductionmentioning

confidence: 99%

Thermally Stable Nanoporous ZrO₂/SiO₂ Hybrid Aerogels for Thermal Insulation

Liu

Gao

Liu

et al. 2019

ACS Appl. Nano Mater.

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Compared with single-component aerogels, hybrid aerogels with multiple components possess enhanced properties, especially high thermal stabilities. Thermal stability improvement depends on the mixing between the various components. In the present research, a ZrO2/SiO2 hybrid aerogel was representatively chosen to study the mixing behaviors and resultant thermal stabilities. A series of ZrO2/SiO2 hybrid aerogels were synthesized by using different sol–gel parameters to study shrinkage, nanopore collapse, and crystallization behavior upon heat treatment. The sol–gel hybridization of weakly branched ZrO2 and SiO2 clusters was found to provide maximum mixing of ZrO2/SiO2. The highly mixed hybrid aerogel, with a ratio of 86/14 w/w ZrO2/SiO2, showed the best thermal stability. The thermally stable ZrO2/SiO2 hybrid aerogel, after incorporation into a mullite fiber blanket, showed very low thermal conductivities of 0.026 ± 0.001, 0.037 ± 0.001, and 0.058 ± 0.002 W/(m K) at 600, 800, and 1000 °C, respectively. It was suggested that weakly branched ZrO2 and SiO2 clusters preferred to freely tangle with each other during the preparation procedure, achieving the most highly mixed ZrO2/SiO2 hybrid with the maximum synergistic effect. This hybrid strategy may provide pathways in designing other multiple-component hybrid aerogels.

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Effect of the doping agent nature on the characteristic and catalytic properties of aerogel zirconia catalysts doped with sulfate groups or heteropolytungstic acid

Cited by 10 publications

References 60 publications

The investigation of an organic acid assisted sol–gel method for preparing monolithic zirconia aerogels

The investigation of an organic acid assisted sol–gel method for preparing monolithic zirconia aerogels

Direct sulfation of a Zr-based metal-organic framework to attain strong acid catalysts

Thermally Stable Nanoporous ZrO₂/SiO₂ Hybrid Aerogels for Thermal Insulation

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Effect of the doping agent nature on the characteristic and catalytic properties of aerogel zirconia catalysts doped with sulfate groups or heteropolytungstic acid

Cited by 10 publications

References 60 publications

The investigation of an organic acid assisted sol–gel method for preparing monolithic zirconia aerogels

The investigation of an organic acid assisted sol–gel method for preparing monolithic zirconia aerogels

Direct sulfation of a Zr-based metal-organic framework to attain strong acid catalysts

Thermally Stable Nanoporous ZrO2/SiO2 Hybrid Aerogels for Thermal Insulation

Contact Info

Product

Resources

About

Thermally Stable Nanoporous ZrO₂/SiO₂ Hybrid Aerogels for Thermal Insulation