Structure and photoluminescence properties of sol–gel TiO2–SiO2 films

Song, Chun; Lü, Meng Kai; Yang, Ping; Xü, Dong; Yuan, Duorong

doi:10.1016/s0040-6090(02)00440-6

Cited by 82 publications

(54 citation statements)

References 23 publications

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“…It has been reported that the radius of Si 4+ ions is 0.41 Å while it is 0.68 Å for Ti 4+ ions, Table 1 BET surface areas and total pore volumes of pure silica and SiO 2 -TiO 2 mixed oxides so the substitution of Si 4+ by larger tetrahedra of Ti 4+ can cause some distortion in the SiO 2 -TiO 2 network or in the silica-rich matrix. This change in crystal structure is therefore reflected in shifts in the diffraction peak positions [27]. In the case of mixed oxides with Si/Ti\1, diffraction peaks corresponding to anatase crystals can be observed and increase slightly with an increase in titanium content, revealing the formation of crystalline titania.…”

Section: Crystal Structurementioning

confidence: 99%

Silica–Titania mixed Oxides: Si–O–Ti Connectivity, Coordination of Titanium, and Surface Acidic Properties

et al. 2008

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A series of SiO 2 -TiO 2 mixed oxides was prepared by the sol-gel route, and the influence of several important preparation parameters (Ti precursors, content, and calcination temperature) on the Si-O-Ti connectivity, coordination of titanium and surface acidity has been studied using various analytical techniques. The solids obtained were largely amorphous and characterized by Ti enrichment on surfaces with low titanium content; however, the addition of titanium greater than 50 mol% into the SiO 2 matrix led to significant phase separation of crystalline anatase. The Ti atoms are tetrahedrally coordinated with Si/Ti ratios higher than 10 and gradually enter into octahedral positions in the silica matrix with further increase in the titanium content. High-temperature treatment can break Si-O-Ti linkages and eliminate hydroxyl groups, resulting in a decrease in acid site density.

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Section: Crystal Structurementioning

confidence: 99%

Silica–Titania mixed Oxides: Si–O–Ti Connectivity, Coordination of Titanium, and Surface Acidic Properties

et al. 2008

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“…In addition to the blue shift, the Hf containing samples are distinguished by a broad absorption band from 850-1150 cm À1 . Significant peaks from M-O-Si bonds in the cross-linked polymer state are known to fall in the 900-1000 cm À1 range, where M = Ti, 16,17 Nb, 18 Ta, 19 V, 20 Zr, 21 Hf. [22][23][24] The broad absorption supports the concept that Hf-O-Si bonds form in the cross-linked polymer state.…”

mentioning

confidence: 99%

Ab inito and FTIR Studies of HfSiCNO Processed from the Polymer Route

2014

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The reactions between polysilazane and hafnium-butoxide precursors are followed from the liquid, to the cross-linked, and finally to the ceramic state by infrared spectroscopy. We find evidence of formation of Hf-N bonds in the liquid state, and Hf-O-Si bonds in the cross-linked polymer state. Results from ab inito calculations for the ceramic state are presented. They show that Hf behaves like Si, forming bonds with C, N, and O in proportion of the Hf/Si ratio in the compounds. The average values of such bonds formed by Hf, relative to silicon, are 11.2, 17.8, and 24.4%, which is in reasonable agreement with the overall Hf/Si ratio in the samples (8%, 15% and 22%). It is concluded that it is appropriate to express the composition of these compounds in terms of the Hf/Si ratio. The X-ray data that show the emergence of weak diffraction peaks for monoclinic HfO 2 when the Hf/Si ratio is 0.22, but not at lower concentrations of Hf [K. Terauds and R. Raj, J. Am. Ceram. Soc., 96, 2117-2123(2013].

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“…• (101) using the Debye-Scherrer equation [29]. The average sizes of the anatase TiO 2 in hydrophobic TiO 2 pillared clay and TiO 2 pillared clay were calculated as 19.9 nm and 14.2 nm, respectively.…”

Section: X-ray Diffraction (Xrd) Patternsmentioning

confidence: 99%

Photocatalytic degradation of dimethyl phthalate ester using novel hydrophobic TiO2 pillared montmorillonite photocatalyst

Ding

et al. 2008

Res. Chem. Intermed.

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Abstract-TiO 2 pillared montmorillonites were prepared by introducing Ti 4+ into a layer of montmorillonite modified with or without cetyltrimethylammonium bromide. The components and texture of the prepared composites were characterized by thermogravimetric analysis, X-ray powder diffraction and scanning electron microscopy. The adsorption and photocatalytic degradation performance of a model environmental endocrine disruptor, dimethyl phthalate ester, were investigated using this newly prepared hydrophobic TiO 2 pillared montmorillonite photocatalyst. The adsorption of dimethyl phthalate ester from water varied from 9% to 28% on the prepared hydrophobic photocatalyst. Although the experimental results showed that the photocatalytic activity of the hydrophobic photocatalyst was slightly lower than that of hydrophilic one, electron spin resonance verified that hydroxyl radicals were also generated in hydrophobic TiO 2 pillared montmorillonite photocatalyst under UV irradiation. To elucidate the decomposition mechanism of dimethyl phthalate ester, 12 main photocatalytic intermediates were identified during the photocatalytic degradation process, and a plausible degradation mechanism was also proposed.

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Structure and photoluminescence properties of sol–gel TiO2–SiO2 films

Cited by 82 publications

References 23 publications

Silica–Titania mixed Oxides: Si–O–Ti Connectivity, Coordination of Titanium, and Surface Acidic Properties

Silica–Titania mixed Oxides: Si–O–Ti Connectivity, Coordination of Titanium, and Surface Acidic Properties

Ab inito and FTIR Studies of HfSiCNO Processed from the Polymer Route

Photocatalytic degradation of dimethyl phthalate ester using novel hydrophobic TiO2 pillared montmorillonite photocatalyst

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