Formation and Characterization of High Surface Area Thermally Stabilized Titania/Silica Composite Materials via Hydrolysis of Titanium(IV) tetra-Isopropoxide in Sols of Spherical Silica Particles

Khalil, Kamal M.S.; El-Samahy, Ahmed A.; Elanany, Mohamed

doi:10.1006/jcis.2002.8268

Cited by 50 publications

(37 citation statements)

References 28 publications

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“…Significant research has focussed on methods of stabilising nano-sized TiO 2 particles on different supports to prevent agglommeration. TiO 2 particles have been immobilised on silica nanospheres [28] and thin films [26,[29][30][31], on Fe-filled carbon nanocapsules [32], within the interlayer spaces of pillared clays [4,33] and on the surface of exfoliated clay sheets, such as laponite .…”

Section: Introductionmentioning

confidence: 99%

Synthesis and characterisation of clay-supported titania photocatalysts

Daniel

Frost

Zhu

2007

Journal of Colloid and Interface Science

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This study examines the use of laponite, a synthetic smectite, which forms exfoliated silicate layers when dispersed in water, as an inorganic support for titania nanocrystals. Titania nanocrystals are prepared prior to addition to the clay dispersion, by a sol-gel synthesis incorporating a microwave hydrothermal step. The characteristics of the resultant structure such as titania phase, crystallite size and particulate size are examined via X-Ray Diffraction (XRD), Transmission Electron Spectroscopy (TEM) and Infrared Spectroscopy.

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Section: Introductionmentioning

confidence: 99%

Synthesis and characterisation of clay-supported titania photocatalysts

Daniel

Frost

Zhu

2007

Journal of Colloid and Interface Science

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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: 99%

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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“…Different precursors were used to synthesize titania, e.g., TiX 4 at X = Cl, OCH(CH 3 ) 2 and other OR [41][42][43][44][45][46][47] which could be transformed through oxidation, hydrolysis/dehydration, and thermal decomposition to form titania. Reactions at relatively low temperatures and subsequent calcination at T < 850 K give amorphous titania [48] or a mixture of anatase with the amorphous phase [25,28,33,35]. Elevating T r leads to the formation of a portion of rutile and its contribution increases with T r .…”

Section: Introductionmentioning

confidence: 99%

Titania deposits on nanosilicas

Gun'ko¹,

Богатырев²,

Лебода³

et al. 2009

Annales UMCS, Chemistry

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Titania (content C TiO2 = 2.7-20.0 wt%) was synthesized on different fumed silica substrates (A-50, A-100, A-380) using Ti[OCH(CH 3 ) 2 ] 4 as a precursor interacting with silica/adsorbed water in 2-propanol or CCl 4 medium, dried and then heated at 1073 K for 1 h. Initial and pretreated nanosilicas and titania/silicas were studied using XRD, adsorption, FTIR, TEM, AFM, and TPD-MS methods. The morphology of grafted titania (anatase/rutile/amorphous phase composition, particle size distribution, aggregation, textural porosity) depends on the types of a nanosilica matrix and a solvent, suspension treatments and reaction conditions.

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Formation and Characterization of High Surface Area Thermally Stabilized Titania/Silica Composite Materials via Hydrolysis of Titanium(IV) tetra-Isopropoxide in Sols of Spherical Silica Particles

Cited by 50 publications

References 28 publications

Synthesis and characterisation of clay-supported titania photocatalysts

Synthesis and characterisation of clay-supported titania photocatalysts

Infrared absorption spectra and structure of TiO2-SiO2 composites

Titania deposits on nanosilicas

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