Titania–silica as catalysts: molecular structural characteristics and physico-chemical properties

Gao, Xueqing; Wachs, Israel E.

doi:10.1016/s0920-5861(99)00048-6

Cited by 643 publications

(485 citation statements)

References 120 publications

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“…Raman analysis showed for both Ti-SiO 2 supports the appearance of a band at 950 cm -1 which is characteristic of Ti-O-Si vibrations. 33 A band at 144 cm -1 , characteristic of TiO 2 crystallites, 33 was not present.…”

Section: Catalyst Preparation and Characterizationmentioning

confidence: 94%

Mechanistic Study into the Direct Epoxidation of Propene over Gold/Titania Catalysts

2005

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The epoxidation of propene over gold/titania based catalysts was investigated using different techniques. Infrared spectroscopic information showed that one key step in the reaction mechanism is a reaction catalyzed by gold between titania surface groups and propene. In this reaction step, a bidentate propoxy species is formed on titania. This species adsorbs strongly on the catalyst, and it is the same species which is formed when propene oxide adsorbs on titania. Gravimetrical adsorption experiments and catalytic tests show that product adsorption and desorption are important factors determining the catalytic activity and the catalyst stability. By combining the information from different techniques, a kinetic mechanism is proposed.

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Section: Catalyst Preparation and Characterizationmentioning

confidence: 94%

Mechanistic Study into the Direct Epoxidation of Propene over Gold/Titania Catalysts

2005

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“…Among the various photocatalytic materials that have been used, most attention has focused on titanium dioxide (TiO 2 ) as a photocatalystin diverse areas ranging from water and air treatment to self-cleaning surfaces.Nanoparticles have been prepared by many methods such as Langmuir-Blodgett filmsYi et al [7], vesiclesYoun et al [8]and reverse microemulsionsFendler et al [8].The chemical and physical properties exhibited by these materials depend,amongothers,on both the composition and the degree of homogeneity.Therefore, different synthesis strategies have been developed Toba et al [9], Gao et al [10].such as co-precipitation,flame hydrolysis, impregnation,chemicalvapourdeposition,etc.The sol-gel route has demonstrated a high potential for controlling the bulk and surface properties of the oxides (Ward et al [11],Liu et al [12], Schraml-Marth et al [13]). Depending on the drying conditions the binary oxides could be obtained as aerogels, either by supercritical drying Pajonk et al [14], Dusi et al [15],or by silanization of the material previously to a conventional drying Sotelo et al [16].Additionally, non-hydrolytic sol-gel routes have been also reported in the literatureHay et al [17].…”

Section: Introductionmentioning

confidence: 99%

Synthesis of Titanium Dioxide Nanoparticles by Sol-Gel Technique

Devi¹,

Venckatesh²,

Sivaraj³

2014

IJIRSET

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Nanosized Titanium dioxide (TiO 2 ) powder was synthesized via sol-gel method using titanium tetraisopropoxide (TTIP) as the precursor. The as prepared nano powder was used for further characterization. The phase transformation was investigated by an X-ray diffractometer (XRD). The anatase structure of titanium dioxide was obtained after calcination. The microstructure was characterized by a Scanning Electron Microscope (SEM).

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“…The . [29] On the other hand, small intensive peaks connected with free reactive groups of chitosan can be attributed to a possible interaction between the polymer and other components. [3] FTIR spectra of synthesized hybrid materials showed that the obtained structures are characterized with stable silica network with existig chitosan and TiO 2 components.…”

Section: ¡1mentioning

confidence: 99%

Structure and properties of innovative silica hybrid materials synthesized for environmental applications

Todorova

Chernev

Okolie

et al. 2015

Biotechnology & Biotechnological Equipment

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Today, environmental protection is one of the main goals in the strive to preserve the human existence. Development in this area requires invention of new materials, which can reduce the levels of pollution. Hybrid materials are suitable for this purpose, because they combine different desirable properties existing in separate sources into one unique and accessible structure. Most of the commonly used materials for the degradation of different kind of pollutants are based on titanium dioxide, because of its photocatalytic activity under UV irradiation. Innovative silica hybrid materials, containing an organic component (chitosan) and titanium nanoparticles, were successfully synthesized via the solÀgel method and tetraethyl orthosilicate was used as a silica source and network former. Interaction between the chitosan and titanium units, and their influence on the structure of final material, were observed and discussed. A homogeneous structure with an even distribution of titanium and chitosan particles was visible from scanning electron microscopy (SEM) micrographs and the particle size varied between 50 and 150 nm. The formed silica network, characteristic peaks of chitosan and titanium groups and possible interactions between them are observed from Fourier transform infrared (FTIR) spectroscopy spectra and nuclear magnetic resonance (NMR) spectroscopy results. The behaviour of the synthesized silica hybrids after thermal treatment was investigated via differential thermal/thermo-gravimetric analysis (DTA/TG) analysis and the sorption and degradation activities of the obtained hybrid materials were investigated using a solution of methyl orange as model pollutant. The structure and properties of the synthesized silica hybrid materials assert their potential application in environmental remediation due to their photocatalytic degradation and sorption activities against pollutants.

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Titania–silica as catalysts: molecular structural characteristics and physico-chemical properties

Cited by 643 publications

References 120 publications

Mechanistic Study into the Direct Epoxidation of Propene over Gold/Titania Catalysts

Mechanistic Study into the Direct Epoxidation of Propene over Gold/Titania Catalysts

Synthesis of Titanium Dioxide Nanoparticles by Sol-Gel Technique

Structure and properties of innovative silica hybrid materials synthesized for environmental applications

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