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Wet-chemistry processing of powdery raw material for high-tech ceramics.

Trusova EA, Vokhmintcev KV, Zagainov IV - Nanoscale Res Lett (2012)

Bottom Line: The purpose of this study was to develop wet-chemistry approaches for the synthesis of ultradispersed and mesoporous metal oxide powders and powdery composites intended for usage in the production of ceramic materials with desired properties.It was found that morphological parameters of the metal oxide obtained by the modified sol-gel technique depend nonlinearly on the initial molar ratio value of the sol stabilizer and metal in the reaction medium as well as the nature of the stabilizer.The developed laboratory technology corresponds to the conception of soft chemistry and may be adapted to the manufacture of ultradispersed materials for catalysis, solar cells, fuel cells, semiconductors, sensors, low-sized electronic devices of new generation, etc.

View Article: PubMed Central - HTML - PubMed

Affiliation: Laboratory of Functional Ceramics, A,A, Baikov Institute of Metallurgy and Materials Science, Russian Academy of Sciences, Leninsky pr, 49, Moscow, 119991, Russia. vokirill@gmail.com.

ABSTRACT
The purpose of this study was to develop wet-chemistry approaches for the synthesis of ultradispersed and mesoporous metal oxide powders and powdery composites intended for usage in the production of ceramic materials with desired properties. The focus is on the development of template synthesis of mesoporous metal silicates as well as obtaining nano- and subnanopowders by a modified sol-gel technique and template methods. Families of mesoporous (2 to 300 nm) metal silicates and nano-oxides and subnanopowders (4 to 300 nm) were synthesized by the template method and modified sol-gel technique, respectively. Texture and morphology of the obtained objects have been studied by X-ray diffraction, scanning electron microscopy, transmission electron microscopy, Fourier transform infrared spectroscopy, Brunauer-Emmett-Teller analysis, and N2 adsorption-desorption. It was found that morphological parameters of the metal oxide obtained by the modified sol-gel technique depend nonlinearly on the initial molar ratio value of the sol stabilizer and metal in the reaction medium as well as the nature of the stabilizer. It has been shown that the nature of structure-directing components determines the morphology of the silicate obtained by the template method: dispersion and shape of its particles. The developed laboratory technology corresponds to the conception of soft chemistry and may be adapted to the manufacture of ultradispersed materials for catalysis, solar cells, fuel cells, semiconductors, sensors, low-sized electronic devices of new generation, etc.

No MeSH data available.


Related in: MedlinePlus

FTIR spectra of Ti (a), Ge (b), and Fe (c) silicates calcined at 500°C.
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Figure 2: FTIR spectra of Ti (a), Ge (b), and Fe (c) silicates calcined at 500°C.

Mentions: The key point of the template method is the interaction between globules formed around the metal and silicium ions in the 3D template. It has been shown that in the presence of the OH- or H+ groups as catalysts, 3D oligomeric organic-inorganic gels can be formed by different means. As a result of these differences, the formation of silicates with a different morphology was realized. We compared the structures of silica samples obtained by base and acid catalyses. Mesoporous structures consisting of hexagonal nanocrystals with a side size of about 50 to 70 nm were obtained by base catalysis (Figure 1a). In the case of acid catalysis, calcined silica has a mesoporous structure and consists of spheres with diameters of about 20 to 40 nm (Figure 1b). The titanium silicate Ti0.03Si0.97O2 obtained by base hydrolysis consisted of granules with sizes of 30 to 50 μm (Figure 1c) which consist of nanotubes with outside diameters of 40 to 60 nm (Figure 1d). In obtained metal silicates, some silicium ions were isomorphically substituted by metal ions. This fact was confirmed by FTIR measurement (Figure 2), which shows a shift of characteristic bands that corresponded to the asymmetric silanol group (region 1,000 to 1,200 cm-1) Si-OH in the greater wave number region with an increase of the metal atom size. The comparison of microphotos in Figure 3 shows that substitution of a template by another one leads to changes in the architecture of formed globules in the metal-silicium gel and eventually to changes in the morphology of obtained aluminum silicates.


Wet-chemistry processing of powdery raw material for high-tech ceramics.

Trusova EA, Vokhmintcev KV, Zagainov IV - Nanoscale Res Lett (2012)

FTIR spectra of Ti (a), Ge (b), and Fe (c) silicates calcined at 500°C.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3275523&req=5

Figure 2: FTIR spectra of Ti (a), Ge (b), and Fe (c) silicates calcined at 500°C.
Mentions: The key point of the template method is the interaction between globules formed around the metal and silicium ions in the 3D template. It has been shown that in the presence of the OH- or H+ groups as catalysts, 3D oligomeric organic-inorganic gels can be formed by different means. As a result of these differences, the formation of silicates with a different morphology was realized. We compared the structures of silica samples obtained by base and acid catalyses. Mesoporous structures consisting of hexagonal nanocrystals with a side size of about 50 to 70 nm were obtained by base catalysis (Figure 1a). In the case of acid catalysis, calcined silica has a mesoporous structure and consists of spheres with diameters of about 20 to 40 nm (Figure 1b). The titanium silicate Ti0.03Si0.97O2 obtained by base hydrolysis consisted of granules with sizes of 30 to 50 μm (Figure 1c) which consist of nanotubes with outside diameters of 40 to 60 nm (Figure 1d). In obtained metal silicates, some silicium ions were isomorphically substituted by metal ions. This fact was confirmed by FTIR measurement (Figure 2), which shows a shift of characteristic bands that corresponded to the asymmetric silanol group (region 1,000 to 1,200 cm-1) Si-OH in the greater wave number region with an increase of the metal atom size. The comparison of microphotos in Figure 3 shows that substitution of a template by another one leads to changes in the architecture of formed globules in the metal-silicium gel and eventually to changes in the morphology of obtained aluminum silicates.

Bottom Line: The purpose of this study was to develop wet-chemistry approaches for the synthesis of ultradispersed and mesoporous metal oxide powders and powdery composites intended for usage in the production of ceramic materials with desired properties.It was found that morphological parameters of the metal oxide obtained by the modified sol-gel technique depend nonlinearly on the initial molar ratio value of the sol stabilizer and metal in the reaction medium as well as the nature of the stabilizer.The developed laboratory technology corresponds to the conception of soft chemistry and may be adapted to the manufacture of ultradispersed materials for catalysis, solar cells, fuel cells, semiconductors, sensors, low-sized electronic devices of new generation, etc.

View Article: PubMed Central - HTML - PubMed

Affiliation: Laboratory of Functional Ceramics, A,A, Baikov Institute of Metallurgy and Materials Science, Russian Academy of Sciences, Leninsky pr, 49, Moscow, 119991, Russia. vokirill@gmail.com.

ABSTRACT
The purpose of this study was to develop wet-chemistry approaches for the synthesis of ultradispersed and mesoporous metal oxide powders and powdery composites intended for usage in the production of ceramic materials with desired properties. The focus is on the development of template synthesis of mesoporous metal silicates as well as obtaining nano- and subnanopowders by a modified sol-gel technique and template methods. Families of mesoporous (2 to 300 nm) metal silicates and nano-oxides and subnanopowders (4 to 300 nm) were synthesized by the template method and modified sol-gel technique, respectively. Texture and morphology of the obtained objects have been studied by X-ray diffraction, scanning electron microscopy, transmission electron microscopy, Fourier transform infrared spectroscopy, Brunauer-Emmett-Teller analysis, and N2 adsorption-desorption. It was found that morphological parameters of the metal oxide obtained by the modified sol-gel technique depend nonlinearly on the initial molar ratio value of the sol stabilizer and metal in the reaction medium as well as the nature of the stabilizer. It has been shown that the nature of structure-directing components determines the morphology of the silicate obtained by the template method: dispersion and shape of its particles. The developed laboratory technology corresponds to the conception of soft chemistry and may be adapted to the manufacture of ultradispersed materials for catalysis, solar cells, fuel cells, semiconductors, sensors, low-sized electronic devices of new generation, etc.

No MeSH data available.


Related in: MedlinePlus