Heat-resistant, strong titania aerogels achieved by supercritical deposition

Zu, Guoqing; Shen, Jun; Wang, Wen-Qin; Lian, Yunsong; Zou, Li‐Ping; Zhang, Yewen; Liu, Bin; Zhang, Fan

doi:10.1016/j.supflu.2015.06.001

Cited by 17 publications

(9 citation statements)

References 23 publications

(32 reference statements)

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“…There are no significant differences between the curves. The broad absorption bands at ~ 3390 cm −1 and ~ 1633 cm −1 are attributed to the stretching vibrations of the hydroxyl (OH) groups on the surface and the bending vibrations of the adsorbed water molecules (H–O–H), respectively [ 38 , 39 , 40 , 41 ]. The peaks at 2970 and 2871 cm −1 of the TiO 2 aerogels belong to the CH 2 symmetric stretching and the CH 3 symmetric stretching of the remaining organic compounds (like dissociative n-hexane (nH) and EtOH) in the pores of the TiO 2 aerogels, respectively [ 38 , 40 , 42 ].…”

Section: Resultsmentioning

confidence: 99%

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Effect of Precursor Nature and Sol-Gel Synthesis Conditions on TiO2 Aerogel’s Structure

Donėlienė¹,

Fataraitė‐Urbonienė

Rudzikas³

et al. 2021

Molecules

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The aim of this investigation was to synthesize high porosity TiO2 aerogel by applying sol-gel and subcritical drying methods and to identify the influence of reagent’s nature and synthesis conditions on their structural and optical properties. Methods of XRD, FT-IR, BET, STA, SEM, and UV-vis were applied to investigate and compare the properties of synthesized TiO2 aerogels and to determine the most effective synthesis route. The structural parameters of the synthesized materials can be varied by changing the precursor type (titanium (IV), isopropoxide (TIP), or tetrabutylorthotitanate (TBOT)) and the nature of the solvent used for additional exchange (n-hexane (nH), cyclohexane (CH), or diethyl ether (DE)). All of the subcritical dried samples show the amorphous structure, which tends to crystallize into the anatase phase after calcination. The number of micro and mesopores and the specific surface area depends on the synthesis conditions. The pores with the highest diameter have been found for additionally nH exchanged and aged aerogel synthesized from precursor TIP. Despite the imperfections in the structure, the produced aerogels show structural and optical properties typical of the TiO2 structures mentioned in the literature.

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Section: Resultsmentioning

confidence: 99%

“…These bands also confirm the crystallization and the transition to the anatase phase. The absorption bands (at 2970, 2871, 1380, 1040–1120 cm −1 ), earlier attributed to the residual organic groups are significantly reduced or entirely disappear after calcination [ 32 , 39 , 41 ].…”

Section: Resultsmentioning

confidence: 99%

Effect of Precursor Nature and Sol-Gel Synthesis Conditions on TiO2 Aerogel’s Structure

Donėlienė¹,

Fataraitė‐Urbonienė

Rudzikas³

et al. 2021

Molecules

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“…Since Kistler suggested the manufacture of silica aerogels in the 1930s [16], great attention has been paid to new advancements in fillers with alumina (Al 2 O 3 ) [17,18] and multilayered fillers mainly from clays [19,20]. Their unique form impacts polyurethane foam, leading to extremely exceptional durability and stability.…”

Section: Introductionmentioning

confidence: 99%

Development and Characterization of Tailored Polyurethane Foams for Shock Absorption

et al. 2022

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In this paper, different types of polyurethane foams (PUR) having various chemical compositions have been produced with a specific density to monitor the microstructure as much as possible. The foam may have a preferential orientation in the cell structure. The cellular polyurethane tends to have stubborn, typical cellular systems with strong overlap reversibility. Free expansion under atmospheric pressure enables formulas to grow until they are refined. Moreover, the physicochemical characterization of the developed foams was carried out. They later are described by apparent density, Shore hardness, Raman spectroscopy analysis, X-Ray diffraction analysis, FTIR, TGA, DSC, and compression tests. The detailed structural characterization was used by scanning electron microscope (SEM) and an optical microscope (MO) to visualize the alveolar polymer’s semi-opened cells, highlighting the opened-cell morphology and chemical irregularities. Polyurethane foams with different structural variables have a spectrum characterization that influences the phase separation and topography of polyurethane foam areas because their bonding capability with hydrogen depends on chain extender nature. These studies may aid in shock absorption production; a methodology of elaboration and characterization of filled polyurethane foams is proposed.

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“…These broad peaks in the mentioned range could also be attributed to a combination of Ti-O-Ti and Ti-O-C bond stretching vibrations [11]. The weak absorption peaks at 1040-1120 cm −1 can be attributed to the stretching vibration of the C-C bonds [21,31]. The peak at 1380 cm −1 is due to the symmetric deformation vibration of CH3 [21].…”

Section: Ft-ir Analysismentioning

confidence: 94%

“…Aging changes the nature of the pore size distribution curves for these aerogels (Figure 2b). The pore distribution curves have been changed from polymodal to unimodal with a peak in the range from 1 to 4 nm for the aerogels without an additional exchange The weak absorption peaks at 1040-1120 cm −1 can be attributed to the stretching vibration of the C-C bonds [21,31]. The peak at 1380 cm −1 is due to the symmetric deformation vibration of CH 3 [21].…”

Section: Bet Analysismentioning

confidence: 99%

The Influence of the Precursor’s Nature and Drying Conditions on the Structure, Morphology, and Thermal Properties of TiO2 Aerogels

Donėlienė¹,

Fataraitė‐Urbonienė

Danchova

et al. 2022

Gels

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A cost-effective solution for the synthesis of high-porosity TiO2 aerogels, which can be used as a mesoporous perovskite network charge-carrier material during the manufacture of solar cells, is described. The effects of the synthesis parameters (precursor (titanium (IV) isopropoxide (TIP) and tetrabutyl orthotitanate (TBOT)), additional solvent exchange (n-hexane (nH), cyclohexane (CH), and diethyl ether (DE)), subcritical drying (800 mbar vacuum, 70 °C, 8 h), aging, and calcination on the aerogel’s structure have been investigated. Methods of XRD, FT-IR, BET, Raman, STA, SEM, UV–vis, and thermal conductivity measurements were applied to find out the relation between the synthesis conditions and the properties of the synthesized aerogels. Amorphous aerogels are polydispersed systems with the highest probability of pore diameter from 0.5 to 15 nm. An nH-exchanged, aged aerogel synthesized from the precursor TIP shows the highest diameter of pores. After calcination, the aerogels tend to crystallize into an anatase phase and the size of the crystallites depends on the precursor’s nature. Calcination leads to a significant increase in both the apparent and true density of the aerogels, and it also results in an increase in porosity and thermal conductivity.

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Heat-resistant, strong titania aerogels achieved by supercritical deposition

Cited by 17 publications

References 23 publications

Effect of Precursor Nature and Sol-Gel Synthesis Conditions on TiO2 Aerogel’s Structure

Effect of Precursor Nature and Sol-Gel Synthesis Conditions on TiO2 Aerogel’s Structure

Development and Characterization of Tailored Polyurethane Foams for Shock Absorption

The Influence of the Precursor’s Nature and Drying Conditions on the Structure, Morphology, and Thermal Properties of TiO2 Aerogels

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