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1.
《Fluid Phase Equilibria》2002,193(1-2):229-243
A thermodynamic model was established to determine ion-exchange conditions for the synthesis of potassium hexatitanate (K2O·6TiO2) and titanium dioxide (TiO2) from potassium tetratitanate (K2O·4TiO2) fiber. In the proposed model equilibrium species in the solid phase and corresponding ion-exchange equilibrium constants at 298.15 K were determined from the experimental data of Sasaki et al. [Inorg. Chem. 24 (1985) 2265]. In order to verify the proposed model, prediction results were compared with experimental data determined in literature and those measured in this work. The comparison shows a good agreement. Based on this, the proposed model was also used to predict more extensive suitable conditions for the synthesis of K2O·6TiO2 and TiO2. 相似文献
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Nanoporous TiO2 photocatalysts were prepared by use of controlled drying method with surfactants. The surface area and porous properties are dependent on the chain length of incorporated surfactant cation. The TiO2 materials prepared in the presence of surfactant molecules during the gel formation exhibit much higher photocatalytic activity than that prepared in the absence of surfactants. 相似文献
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Marina Teixeira Laranjo Natalia Carminati Ricardi Leliz Ticona Arenas Edilson Valmir Benvenutti Matheus Costa de Oliveira Marcos José Leite Santos Tania Maria Haas Costa 《Journal of Sol-Gel Science and Technology》2014,72(2):273-281
In this work we show the synthesis and characterization of TiO2 and TiO2/SiO2 nanoparticles synthesized by sol–gel method using HF and HCl as catalysts. The obtained nanoparticles were analyzed by N2 adsorption–desorption isotherms, transmission electronic microscopy, Ultraviolet–visible spectroscopy and X-ray diffractometry. Mesoporous, homogeneously polycondensed TiO2/SiO2 materials, containing nanocrystalline anatase phase with band gap similar to pure titania were obtained. Films of the powdered oxides were applied to assemble dye sensitized solar cells that presented electrical parameters, Fill Factor and efficiencies similar to devices obtained by only TiO2. The sol–gel route arises as an alternative way to prepare TiO2/SiO2 materials for solar cells. 相似文献
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Ingo G. M. Riccucci C. Bultrini G. Dirè S. Chiozzini G. 《Journal of Thermal Analysis and Calorimetry》2001,66(1):37-46
Amorphous SiO2, TiO2 and xSiO2–(1–x)TiO2 ceramic materials with selected values of x 0.5, 0.7 and 0.9, have been prepared via sol-gel process using silicon tetraethoxysilane (TEOS) and titanium tetraisopropoxide
Ti(OPri)4. By means of the combined use of differential thermal analysis (DTA),thermogravimetry (TG), X-ray diffraction (XRD), scanning
electron microscopy (SEM),X-ray photoelectron spectroscopy (XPS) and X-ray induced Auger electron spectroscopy(XAES), the
surface microchemical structure and morphology of the sol-gel materials have been studied as a function of thermal treatments
carried out in air up to 1200°C. In the range of temperature from 50 to 450°C, DTA-TG results evidence a remarkable mass loss
due to the evaporation of organic solvents entrapped in the sol-gel materials and of the remnant organic components of the
precursor metal alkoxides. In the range of temperature from 400 to about 1000°C, by means of the combined use of DTA, XRD,
XPS and XAES techniques as a function of temperature and of chemical composition, it is possible to evidence the formation
of crystalline phases such as quartz, anatase and rutile. Furthermore, line shape analysis of O1s XPS peak allows to distinguish
between single O–Ti and O–Si bonds and also to disclose the presence of cross linking Si–O–Ti bonds, that act as bridges between
SiO2and TiO2 moieties. As a function of temperature, Si–O–Ti bonds are broken and the formation of new Ti–O and Si–O bonds as in TiO2 and SiO2takes place as well as a silica segregation phenomenon.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
5.
Hui Zhang Duowang Fan Tianzhi Yu Chenglong Wang 《Journal of Sol-Gel Science and Technology》2013,66(2):274-279
Sol–gel dip-coating technique can be used to fabricate SiO2–TiO2 composite film with self-cleaning and anti-reflectance properties from low-cost SiO2 colloid solution and Ti(OC4H9)4. The physical and structural properties have been investigated by UV–visible spectrophotometer, contact angle meter, XRD, FT-IR, FESEM. UV–vis spectra and methyl orange photodegradation experiments showed that the SiO2–TiO2 composite film had high light transmittance and photocatalytic activity. 相似文献
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The nano-ZnFe2O4/TiO2 films possess the functions of desulfurization and degradation for organic pollutants. The sols of ZnFe2O4/TiO2 were prepared by sol-gel method and coated on glass and porous ceramic by vertical coating and dipping-lift processes, respectively, and the samples were obtained after drying and sintering. The composition, appearance, absorption spectrum of the films, and the influence of the film on porous ceramic performances were analyzed using SEM, AFM, UV-Vis spectrometer, and mercury porosimeter, respectively, to determine the operation parameters of the multifunction porous ceramic elements for gas-purification. 相似文献
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This paper reviews acid–base bifunctional catalysis and surface properties (morphology, composition, specific area, acidity/basicity, site density) on TiO2–ZrO2 (abbreviated as TZ) mixed oxides. The phase change from crystalline single oxides (TiO2 and ZrO2) to amorphous TZ mixed oxide results in decreasing grain size and site density, increasing surface area, acid/base amount and strength, and better activity/selectivity. Different acid–base bifunctional mechanisms (concerted, go-together, stepwise) were proposed to interpret the reaction behavior of various reactions (esterification, dehydration, dehydrogenation, isomerization, dehydrocyclization) over the acid–base bifunctional TZ catalysts. 相似文献
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Natalie Smirnova Anna Eremenko Vladimir Gayvoronskij Irina Petrik Yuriy Gnatyuk Galina Krylova Andrey Korchev Alexej Chuiko 《Journal of Sol-Gel Science and Technology》2004,32(1-3):357-362
Titania and silica-based porous coatings have been produced via sol–gel route in the presence of pore-creating agents PEG and viscous solvent -terpineol, or template agents CTAB, as well as triblock copolimer Pluronic P123. Porous titania films were characterised by HR TEM, UV-Vis, XRD, ellipsometry, ARS methods. The dispersion of the refractive index, the porosity (32–39%) and the thickness of the samples were estimated by integrating sphere transmission and reflection spectra with 3D angular resolved light scattering. The catalytic activity of mesoporous TiO2 and TiO2/ZrO2 as well as SiO2-benzophenone films in the process of CrVI to CrIII and Ag+ to Ag0 photoreduction have been studied. 相似文献
11.
Preparation and Characterization of TiO2-pillared Layered HNb3O8 总被引:1,自引:0,他引:1
IntroductionThelayeredcompoundssuchassmectiteclays,me-tallicphosphatesandtransitionmetaloxidespillaredwithinorganicoxideshavebeenattractingmoreandmoreattentionfrombothacademicandindustrialfieldsduetotheirpotentialapplicationsinadsorption,separa-tion,conductionandparticularlycatalysis.1-7NiobatessuchasKNb3O8andK4Nb6O17,andthecorrespondingprotonicoxides,HNb3O8andH4Nb6O17,aremembersofthefamilyoflayeredtransitionmetaloxidesbasedonoctahedralframeworkstructure,inwhichK+orH+liesbetweenlayersbuil… 相似文献
12.
《Solid State Sciences》2001,3(3):291-299
Preparation of core-shell structured TiO2–BaCO3 particles as precursor of BaTiO3 genesis, proceeds using a two step procedure, by first coating the TiO2 core by Ba(OH)2 shell followed by conversion of the shell region with CO2 gas by the formation of BaCO3. Straightforward experimental results reveal environmental scanning electron microscopy (ESEM) and scanning transmission electron microscopy (STEM) as suitable methods for analytical characterization of the core and shell regions from individual TiO2–BaCO3 grains. Evidence of coating the whole ensemble of TiO2 particles is possible using Photo Electro Motive Force (Photo EMF, PEMF) measurements. This method is able to indicate very sensitively changes of surface properties of TiO2 after coating with Ba(OH)2 and BaCO3, respectively. PEMF measurements were used for the first time with concern to this topic. 相似文献
13.
Bing Han Yalin Guo Yike Huang Dr. Wei Xi Jie Xu Prof. Jun Luo Haifeng Qi Yujing Ren Xiaoyan Liu Prof. Botao Qiao Prof. Tao Zhang 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2020,132(29):11922-11927
Strong metal–support interaction (SMSI) has gained great attention in the field of heterogeneous catalysis. However, whether single-atom catalysts can exhibit SMSI remains unknown. Here, we demonstrate that SMSI can occur on TiO2-supported Pt single atoms but at a much higher reduction temperature than that for Pt nanoparticles (NPs). Pt single atoms involved in SMSI are not covered by the TiO2 support nor do they sink into its subsurface. The suppression of CO adsorption on Pt single atoms stems from coordination saturation (18-electron rule) rather than the physical coverage of Pt atoms by the support. Based on the new finding it is revealed that single atoms are the true active sites in the hydrogenation of 3-nitrostyrene, while Pt NPs barely contribute to the activity since the NP sites are selectively encapsulated. The findings in this work provide a new approach to study the active sites by tuning SMSI. 相似文献
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M. Shabir Mahr T. Hübert B. Schartel H. Bahr M. Sabel H. Militz 《Journal of Sol-Gel Science and Technology》2012,64(2):452-464
Sol–gel derived TiO2 and SiO2-wood inorganic composites are prepared by direct vacuum infiltration of silicon and titanium alkoxide based precursors in pine sapwood in one or two cycles followed by a controlled thermal curing process. The resulting flame retardancy effect is investigated under two different fire scenarios using cone calorimetry and oxygen index (LOI). Heat release rates (HRR) especially the values for the second peak, are reduced moderately for all single layered composites. This effect is more pronounced for double layered composites where HRR was reduced up to 40 % showing flame retardancy potential in developing fires. Beside this, smoke release was lowered up to 72 % indicating that these systems had less fire hazards compared to untreated wood, whereas no meaningful improvement is realized in terms of fire load (total heat evolved) and initial HRR increase. However impressively, the LOI of the composites were increased up to 41 vol% in comparison to 23 vol% for untreated wood displaying a remarkable flame retardancy against reaction to a small flame. An approximate linear interdependence among the fire properties and the material loading as well as fire residue was observed. A residual protection layer mechanism is proposed improving the residue properties for the investigated composites. 相似文献
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Bergamonti L. Alfieri I. Lorenzi A. Montenero A. Predieri G. Di Maggio R. Girardi F. Lazzarini L. Lottici P. P. 《Journal of Sol-Gel Science and Technology》2015,73(1):91-102
Journal of Sol-Gel Science and Technology - The sol–gel synthesis of water-based sols of nanocrystalline TiO2 in a large pH range (1.3–10.6) was carried out by acid hydrolysis of... 相似文献
18.
《Journal of solid state chemistry》1987,71(1):103-108
A systematic study of compound and solid-solution formation in the system Li2ONb2O5TiO2 has been made. Several solid-solution series, based on LiNbO3, LiNb3O8, Li2Nb28O71, Li2TiO3, phase M, Li2Ti3O7, and TiO2, have been characterized. In all cases, the principal solid-solution mechanism appears to involve stoichiometric formulae with constant overall cation content. One new phase, of approximate formula Li13TiNb5O21, has been prepared. A subsolidus phase diagram for the ternary system is presented. 相似文献
19.
In this paper, TiO2 loaded on activated carbon fibers (ACF) was prepared by a coating treatment, followed by calcination at different temperatures in air atmosphere. The photocatalyst developed was characterized by SEM, XRD, XPS and UV-Vis adsorption spectroscopy. It was observed from SEM images that TiO2 loaded on ACF was in the form of small clusters with nanometer size. As confirmed by XRD and XPS determinations, the crystalline pattern of immobilized TiO2 was still anatase-form after calcination, and the micrographic structure and surface properties of ACF have not been damaged by the deposition process and calcination at different temperatures. Photocatalytic degradation of methylene blue (MB) in aqueous .solution was investigated using TiOE/ACF as photocatalyst. The comparison of photolysis, absorption and photocatalysis was carded out. The results indicated that the photocatalysis process of combined photocatalyst showed much higher degradation rate than that of photolysis and absorption processes. In addition, the possibility of cyclic usage of the photocatalyst was also confirmed. 相似文献
20.
Yoichi Ishibai Takashi Nishikawa Shigeyoshi Miyagishi 《Journal of Dispersion Science and Technology》2013,34(8):1093-1098
Nano‐sized TiO2 sol was prepared through a wet synthesis process. The synthesis procedure involved hydrolysis of TiCl4, acid treatment, and a SiO2 surface‐modifying process. Before surface modification, the TiO2 suspension was treated with acid to remove Na ions, soluble TiO2, and other impurities. The acid treatment of a TiO2 suspension at a higher temperature was proved to be useful for effective SiO2 modification. The colloidal sol provided high transparency in visible light as well as excellent UV‐shielding properties. Surface modification of TiO2 particles with SiO2 greatly improved both the dispersing stability in neutral pH and the photostability of TiO2 colloidal sol. 相似文献