Zirconia-based alumina compound aerogels with enhanced mesopore structure

Jung, Hae Noo Ree; Kim, Tae-Hee; Cho, Hyung Hee; Park, Hyung Ho

doi:10.1016/j.ceramint.2018.03.081

Cited by 13 publications

(6 citation statements)

References 45 publications

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“…Metal alkoxides are generally used as non-silica-based precursors in the synthesis of aerogels [41,42,43], but they are costly and their reactivity is hard to control [44]. In this study, cost effective tin chloride was selected as the precursor and propylene oxide was used to initialize the sol–gel process for the synthesis of the SnO 2 aerogel/rGO nanocomposites.…”

Section: Resultsmentioning

confidence: 99%

Facile Synthesis of SnO2 Aerogel/Reduced Graphene Oxide Nanocomposites via in Situ Annealing for the Photocatalytic Degradation of Methyl Orange

et al. 2019

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SnO2 aerogel/reduced graphene oxide (rGO) nanocomposites were synthesized using the sol–gel method. A homogeneous dispersion of graphene oxide (GO) flakes in a tin precursor solution was captured in a three-dimensional network SnO2 aerogel matrix and successively underwent supercritical alcohol drying followed by the in situ thermal reduction of GO, resulting in SnO2 aerogel/rGO nanocomposites. The chemical interaction between aerogel matrix and GO functional groups was confirmed by a peak shift in the Fourier transform infrared spectra and a change in the optical bandgap of the diffuse reflectance spectra. The role of rGO in 3D aerogel structure was studied in terms of photocatalytic activity with detailed mechanism of the enhancement such as electron transfer between the GO and SnO2. In addition, the photocatalytic activity of these nanocomposites in the methyl orange degradation varied depending on the amount of rGO loading in the SnO2 aerogel matrix; an appropriate amount of rGO was required for the highest enhancement in the photocatalytic activity of the SnO2 aerogel. The proposed nanocomposites could be a useful solution against water pollutants.

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Section: Resultsmentioning

confidence: 99%

Facile Synthesis of SnO2 Aerogel/Reduced Graphene Oxide Nanocomposites via in Situ Annealing for the Photocatalytic Degradation of Methyl Orange

et al. 2019

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“…Hrubesh et al theoretically predicted that ZrO 2 aerogels would be the best inorganic aerogels for uses at the lowest achievable thermal conductivity . Many other studies have researched ZrO 2 aerogels. − However, upon heating, pristine ZrO 2 aerogels can shrink in its longest dimension up to 50% of its original size . Also, when the temperature is high enough, tetragonal crystallized domains appear in amorphous ZrO 2 aerogels followed by a phase transformation to a monoclinic structure .…”

Section: Introductionmentioning

confidence: 99%

“…However, postgelation involves mass and heat transfer through tortuous and space-confined nanopores, where efficiency is lowered, thereby affecting the system costs . In another aspect, secondary phases, for instance, Y 2 O 3 , Al 2 O 3 , and SiO 2 , are designed for incorporation into ZrO 2 aerogels via cogelation for thermal stability improvement. In ceramic science, heterovalent metal oxides, e.g., Y 2 O 3 , produce oxygen vacancies that stabilize tetragonal ZrO 2 , so that phase transformation and monolithic cracks are avoided .…”

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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“…Nanomaterials are a new type of highly effective thermal insulation materials. Numerous studies, both domestic and international, have been conducted on the thermal insulation performance of aerogel nanomaterials [8][9][10][11][12][13][14]. Since hypersonic vehicles entail strict limits on the weight and thickness of the thermal insulation materials used, not only must the latter meet the design requirements of light weight and efficient thermal insulation but its outer surface must also be able to withstand thermal erosion by hot air.…”

Section: Introductionmentioning

confidence: 99%

Experimental and numerical research on high‐temperature thermal insulation performance of lightweight porous ceramic/nanomaterial composite structure

Ren

Wu³

et al. 2019

Materialwissenschaft Werkst

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The thermal protection structure of hypersonic vehicles must meet the design requirements of high efficiency and light weight, and its heating surface must also be able to withstand thermal erosion by high‐speed and high‐temperature airflow. In this paper, a light‐weight porous ceramic material and a lightweight nanoscale thermal insulation material with excellent thermal insulation performance are combined to form an integrated thermal protection structure. Experimental study and numerical simulation of the structure's high‐temperature thermal insulation performance are carried out. The experimental results show that a composite sheet made from a 20 mm‐thick lightweight porous ceramic material and a 10 mm‐thick nanomaterial exhibit a temperature drop of 85 % between its back surface and front surface in four thermal environments (1200, 1000, 800 and 600 °C) at 1800 s. This indicates excellent thermal insulation performance of the composite sheet. In addition, the operating temperature limit (<1000 °C) is obtained through high‐temperature thermal performance tests on single‐layer nanomaterial sheets and scanning electron microscopy results. This provides an important basis for determining and optimizing the thickness ratio of the two materials in composite structure.

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Zirconia-based alumina compound aerogels with enhanced mesopore structure

Cited by 13 publications

References 45 publications

Facile Synthesis of SnO2 Aerogel/Reduced Graphene Oxide Nanocomposites via in Situ Annealing for the Photocatalytic Degradation of Methyl Orange

Facile Synthesis of SnO2 Aerogel/Reduced Graphene Oxide Nanocomposites via in Situ Annealing for the Photocatalytic Degradation of Methyl Orange

Thermally Stable Nanoporous ZrO₂/SiO₂ Hybrid Aerogels for Thermal Insulation

Experimental and numerical research on high‐temperature thermal insulation performance of lightweight porous ceramic/nanomaterial composite structure

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Zirconia-based alumina compound aerogels with enhanced mesopore structure

Cited by 13 publications

References 45 publications

Facile Synthesis of SnO2 Aerogel/Reduced Graphene Oxide Nanocomposites via in Situ Annealing for the Photocatalytic Degradation of Methyl Orange

Facile Synthesis of SnO2 Aerogel/Reduced Graphene Oxide Nanocomposites via in Situ Annealing for the Photocatalytic Degradation of Methyl Orange

Thermally Stable Nanoporous ZrO2/SiO2 Hybrid Aerogels for Thermal Insulation

Experimental and numerical research on high‐temperature thermal insulation performance of lightweight porous ceramic/nanomaterial composite structure

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Product

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Thermally Stable Nanoporous ZrO₂/SiO₂ Hybrid Aerogels for Thermal Insulation