Formation of Nanosized TiO2 in Mesoporous Silica Thin Films

Hua, Zile; Shi, Jianlin; Zhang, Lingxia; Ruan, Meiling; Yan, Jianping

doi:10.1002/1521-4095(20020605)14:11<830::aid-adma830>3.0.co;2-w

Cited by 77 publications

(35 citation statements)

References 13 publications

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“…[40,41,42] Oxides, particularly transition-metal oxides are of special interests because of their catalytic function and electron storage function. The reaction rate of these functions depends on surface area and can be improved by the quantum size effect [43]. It is highly beneficial to fabricate nanosized transition-metal oxides on a suitable substrate in various applications.…”

Section: Wc-co Coatings Fabricated By Warm Sprayingmentioning

confidence: 99%

Warm spraying—a novel coating process based on high-velocity impact of solid particles

Katayama

Kawakita

Watanabe

et al. 2008

Science and Technology of Advanced Materials

154

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In recent years, coating processes based on the impact of high-velocity solid particles such as cold spraying and aerosol deposition have been developed and attracting much industrial attention. A novel coating process called 'warm spraying' has been developed, in which coatings are formed by the high-velocity impact of solid powder particles heated to appropriate temperatures below the melting point of the powder material. The advantages of such process are as follows: (1) the critical velocity needed to form a coating can be significantly lowered by heating, (2) the degradation of feedstock powder such as oxidation can be significantly controlled compared with conventional thermal spraying where powder is molten, and (3) various coating structures can be realized from porous to dense ones by controlling the temperature and velocity of the particles. The principles and characteristics of this new process are discussed in light of other existing spray processes such as high-velocity oxy-fuel spraying and cold spraying. The gas dynamics of particle heating and acceleration by the spraying apparatus as well as the high-velocity impact phenomena of powder particles are discussed in detail. Several examples of depositing heat sensitive materials such as titanium, metallic glass, WC-Co cermet and polymers are described with potential industrial applications.

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Section: Wc-co Coatings Fabricated By Warm Sprayingmentioning

confidence: 99%

Warm spraying—a novel coating process based on high-velocity impact of solid particles

Katayama

Kawakita

Watanabe

et al. 2008

Science and Technology of Advanced Materials

154

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“…The O 1s band appeared at 530.3 eV for the TiO 2 film and 530.5 eV for the TiO 2 /SiO 2 film (Fig. 4b), which is attributable to the Ti-O-Ti components (529.2 eV) [33]. The weak band at 103.4 eV was attributed to Si 2p (Fig.…”

Section: The Preparation and Characterization Of Tio 2 /Sio 2 Composimentioning

confidence: 99%

Electrochemical preparation of TiO2/SiO2 composite film and its high activity toward the photoelectrocatalytic degradation of methyl orange

Zhou

Zhu

et al. 2009

J Appl Electrochem

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Uniform TiO 2 /SiO 2 composite films were prepared on ITO substrates by electrodeposition, and highly photoelectrocatalytic (PEC) activity of the composite films was observed toward the degradation of methyl orange (MO) in aqueous solutions. It was further found that their PEC activity was dependent on the electrodeposition parameters including deposition time, solution pH and SiO 2 content. Under the optimized condition, the PEC degradation of MO on TiO 2 /SiO 2 composite film electrode could be enhanced about 14 times relative to that on neat TiO 2 film electrode. The high PEC activity of the TiO 2 / SiO 2 composite film electrode was mainly attributed to the enhancement of the charge separation of photo-generated electron-hole pairs by the dispersion of SiO 2 nanoparticles in the TiO 2 matrix with the aid of the applied electric field.

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“…Composites based on titanium and silicon dioxides have begun to be used relatively recently as catalysts and photocatalysts for various processes, protective coatings, components of glasses with low linear thermal expansion coefficient, and waveguide materials [1][2][3][4][5][6][7]. The method for obtaining the composite determines the nature and extent of interactions between components.…”

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confidence: 98%

Infrared absorption spectra and structure of TiO2-SiO2 composites

et al. 2008

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The composites xTiO 2 -(1-x)SiO 2 (x = 0.1, 0.5, 0.9) were obtained by coprecipitation from solutions of alkoxides: tetraethoxysilane (TEOS) and titanium tetraisopropoxide (TIPT). Intermolecular interaction of the components of the composite is apparent in the IR absorption spectra in the 928-952 cm -1 region, and is connected with bending vibrations of the Si-O-Ti bond.Introduction. Composites based on titanium and silicon dioxides have begun to be used relatively recently as catalysts and photocatalysts for various processes, protective coatings, components of glasses with low linear thermal expansion coefficient, and waveguide materials [1][2][3][4][5][6][7]. The method for obtaining the composite determines the nature and extent of interactions between components. For mechanical mixing of the individual phases, weak van der Waals interaction occurs. Thorough mixing of the components at the molecular level when obtaining the composite by sol-gel or coprecipitation methods leads to a substantial change in the properties of the end product: the appearance of new catalytically active centers, a shift in the onset of crystallization for the titanium-containing component toward higher temperatures, and accordingly an increase in the thermal stability of the structural and adsorption characteristics of the composite [7]. Formation of Si-O-Ti bonds at the TiO 2 -SiO 2 interface leads to an appreciable change in the electronic structure of the titanium atoms in the composite [8,9]. One possible method for estimating the interaction between components is IR spectroscopy. The absorption band observed in the 910-960 cm -1 region is due to characteristic vibrations of the Si-OH and Si-O-Ti bonds. Its position depends on the chemical composition of the sample and the resolution of the instrument [10,11]. We know that for exhaustive dehydration of SiO 2 , the band in the 940-950 cm -1 region, due to bending vibrations of the Si-OH bond, disappears in the absorption spectra. After appropriate heat treatment of the composite, absorption in this region will be due only to bending vibrations of the Si-O-Ti bond and thus it becomes possible to study the nature and extent of intermolecular interaction between titanium and silicon oxides by IR spectroscopy, which was the subject of this work.The Experiment. The composite was obtained by the coprecipitation method. For this purpose, the specified amounts of tetraethoxysilane (TEOS) and titanium tetraisopropoxide (TIPT) were mixed with isopropyl alcohol, then a solution of water (or ammonium hydroxide) in alcohol was added dropwise with vigorous stirring. The suspension was stirred for 1 h, the residue was separated by filtration and washed with water until the organic components were no longer present. The samples were dried at 120 o C for 5 h and calcined at 350 o C and 650 o C for 3 h. The individual titanium and silicon oxides were obtained under similar conditions. Table 1 gives the conditions for obtaining powders of the individual titanium and silicon oxides and the composit...

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Formation of Nanosized TiO2 in Mesoporous Silica Thin Films

Cited by 77 publications

References 13 publications

Warm spraying—a novel coating process based on high-velocity impact of solid particles

Warm spraying—a novel coating process based on high-velocity impact of solid particles

Electrochemical preparation of TiO2/SiO2 composite film and its high activity toward the photoelectrocatalytic degradation of methyl orange

Infrared absorption spectra and structure of TiO2-SiO2 composites

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