共查询到20条相似文献,搜索用时 15 毫秒
1.
Li Chen Haixia Shen Zhen Lu Cang Feng Su Chen Yanru Wang 《Colloid and polymer science》2007,285(13):1515-1520
TiO2–SiO2 composite nanoparticles were prepared by a sol–gel process. To obtain the assembly of TiO2–SiO2 composite nanoparticles, different molar ratios of Ti/Si were investigated. Polyurethane (PU)/(TiO2–SiO2) hybrid films were synthesized using the “grafting from” technique by incorporation of modified TiO2–SiO2 composite nanoparticles building blocks into PU matrix. Firstly, 3-aminopropyltriethysilane was employed to encapsulate TiO2–SiO2 composite nanoparticles’ surface. Secondly, the PU shell was tethered to the TiO2–SiO2 core surface via surface functionalized reaction. The particle size of TiO2–SiO2 composite sol was performed on dynamic light scattering, and the microstructure was characterized by X-ray diffraction and
Fourier transform infrared. Thermogravimetric analysis and transmission electron microscopy (TEM) employed to study the hybrid
films. The average particle size of the TiO2–SiO2 composite particles is about 38 nm when the molar ratio of Ti/Si reaches to1:1. The TEM image indicates that TiO2–SiO2 composite nanoparticles are well dispersed in the PU matrix. 相似文献
2.
Uraiwan Sirimahachai Nicholas Ndiege Ramesh Chandrasekharan Sumpun Wongnawa Mark A. Shannon 《Journal of Sol-Gel Science and Technology》2010,56(1):53-60
Nanosized TiO2 and nano-anatase TiO2 decorated on SiO2 spherical core shells were synthesized by using a sol–gel method. The synthesized pure TiO2 nano particle and TiO2 grafted on SiO2 sphere with various ratios have been characterized for their structure and morphologies by X-ray diffraction (XRD), X-ray
photoelectron spectroscopy (XPS), Fourier transform infrared spectrophotometry (FTIR) and transmission electron microscopy
(TEM). Their surface areas were measured using the BET method. The photocatalytic activity of all nanocomposites was investigated
using methylene blue as a model pollutant. The synthesized TiO2/SiO2 particles appeared to be more efficient in the degradation of methylene blue pollutant, as compared to pure TiO2 particles. 相似文献
3.
Yanhuai Ding Ping Zhang Zhilin Long Yong Jiang Fu Xu Jianguang Lei 《Journal of Sol-Gel Science and Technology》2008,46(2):176-179
TiO2 nanofibers were prepared from tetrabutyl titanate sol precursors by using electrospun method. X-ray diffraction (XRD) and
atomic force microscope (AFM) were used to characterize their crystal structure and morphology feature. The results demonstrated
that TiO2 nanofibers possessed anatase phase and the average diameter of TiO2 nanofibers was about 150 nm. The photocatalytic property of TiO2 nanofibers was evaluated for the photodecomposition of methyl orange solution. And TiO2 nanofibers exhibited high photocatalytic activities with transfer efficiency about 100% after 20 min. 相似文献
4.
J. A. León-Ramos D. Kibanova P. Santiago-Jacinto Y. Mar-Santiago M. Trejo-Valdez 《Journal of Sol-Gel Science and Technology》2011,57(1):43-50
Crystalline anatase phase TiO2 with photocatalytic properties was obtained through a sol–gel low-temperature hydrothermal process. TiO2 samples doped with tungsten oxide were also obtained by using this synthetic approach. The photocatalytic oxidation of methylene
blue in water was monitored to study the influence of the tungsten doping degree on the photocatalytic degradation performance
of TiO2. The degradation rate constant was further increased by adjusting the tungsten doping degree of hydrothermal TiO2. Also, a much faster photodegradation of methylene blue was achieved using tungsten doped samples baked at 450°C. The results
were compared with those obtained with Degussa P25 used as photocatalyst. The structure and optical properties of tungsten-doped
TiO2 were studied by SEM, X-ray diffraction, UV–vis and DRIFT spectroscopy techniques. 相似文献
5.
Lixue Deng Yinglei Chen Meiyu Yao Shurong Wang Baolin Zhu Weiping Huang Shoumin Zhang 《Journal of Sol-Gel Science and Technology》2010,53(3):535-541
B-doped TiO2 nanotubes (B/TiO2 NTs) were prepared by the combination of sol–gel process with hydrothermal treatment. The prepared catalysts were characterized
by XRD, TEM and XPS. The photocatalytic activity of B/TiO2 NTs was evaluated through the photodegradation of aqueous methyl orange. The results demonstrated that the 1.5% B/TiO2 NTs calcined at 300 °C possessed the best photocatalytic activity. Compared with pure TiO2 nanotubes, the doping with B significantly enhanced the photocatalytic efficiency. 相似文献
6.
M. G. Demidova N. O. Shaparenko T. Yu. Podlipskaya A. I. Bulavchenko 《Russian Journal of Inorganic Chemistry》2017,62(6):715-722
Stable SiO2 and TiO2 organosols were prepared by hydrolyzing tetraethyl orthosilicate (TEOS) in the presence of 6–12 M NH3 and titanium(IV) isopropylate (TTIP) in reverse microemulsions of 0.12–0.25 M bis(2-ethylhexyl) sulfosuccinate (Aerosol OT, AOT) in n-decane with the aqueous pseudophase content of 2–3 vol %, 0.018–0.090 M TEOS, and 0.15–0.55 vol %, 0.003–0.025 M TTIP. The degree of hydrolysis was monitored by IR spectroscopy (for TEOS) and spectrophotometry (for TTIP). Oxide nanoparticles were characterized by photon-correlation spectroscopy (PCS) (D h = 8–100 nm) and laser electrophoresis (ζ-potential = 7.4–11.6 mV). The occurrence of surface potential made it possible to separate the oxides from the excess of surfactant by nonaqueous electrophoresis and to determine particle sizes (7–40 nm) by means of transmission electron microscopy (TEM). 相似文献
7.
Mariusz Walkowiak Monika Osińska Teofil Jesionowski Katarzyna Siwińska-Stefańska 《Central European Journal of Chemistry》2010,8(6):1311-1317
This paper describes the synthesis and properties of a new type of ceramic fillers for composite polymer gel electrolytes.
Hybrid TiO2-SiO2 ceramic powders have been obtained by co-precipitation from titanium(IV) sulfate solution using sodium silicate as the precipitating
agent. The resulting submicron-size powders have been applied as fillers for composite polymer gel electrolytes for Li-ion
batteries based on poly(vinylidene fluoride-co-hexafluoropropylene) (PVdF/HFP) copolymeric membranes. The powders, dry membranes
and gel electrolytes have been examined structurally and electrochemically, showing favorable properties in terms of electrolyte
uptake and electrochemical characteristics in Li-ion cells. 相似文献
8.
Silica and core–shell structured titania/silica (TiO2/SiO2) nanoparticles with particles size ranging from tens to hundreds of nanometers were prepared and deposited onto cotton fabric
substrates by sol–gel process. The morphologies of the nanoparticles were characterized by field-emission scanning electron
microscope (FE-SEM). The photocatalytic decomposition properties as well as UV-blocking properties of the fabrics treated
with SiO2 and TiO2/SiO2 nanoparticles were investigated. 相似文献
9.
Synthesis and characterization of TiO<Subscript>2</Subscript>-montmorillonite nanocomposites and their photocatalytic activity 总被引:1,自引:0,他引:1
Aiqin Zhang Rongbin Zhang Ning Zhang Sanguo Hong Ming Zhang 《Kinetics and Catalysis》2010,51(4):529-533
TiO2 nanoparticles have been synthesized on the surface of exfoliated montmorillonite at a low temperature in benzyl alcohol medium.
According to X-ray diffraction (XRD), N2 adsorption-desorption isotherm and transmisson electron microscopy (TEM), it was found that the intercalation of TiO2 nanoparticles destroyed the ordered structure of montmorillonite to some extent, and the crystallites of the nanocomposites
are assembled to form a house-of-cards structure. The size of the nanoparticles in the interlamellar space is about 4 nm.
The nanocomposites exhibited excellent photocatalytic activity in methylene blue degradation due to the synergetic effect
of the adsorptive ability to organic compound of cetyl trimethylammonium bromide—montmorillonite and the catalytic ability
of TiO2 nanoparticles in it. 相似文献
10.
Jia-Yin Gui Bin Zhou Yan-Hong Zhong Ai Du Jun Shen 《Journal of Sol-Gel Science and Technology》2011,58(2):470-475
With tetraethoxysilane as the organic precursor, gradient density aerogels were fabricated by three different methods: layer-by-layer
gelation, sol-co-gelation and continuous formation technics. Through layer-by-layer method, a 5-layer graded density silica
aerogel whose density ranges from 50 to 200 mg/cm3 was obtained, but it existed a dense skin between adjacent layers which could result in density mutation in the interface.
In order to optimize its interface character, sol-co-gelation technique was created to improve the interdiffusion and smooth
out the density mutation via a self-built device. Finally, on the base of the device and sol-co-gelation technics, a continuous
formation process was developed to fabricate the completely gradient density silica aerogel. Optical microscope and X-ray
phase contrast method were used to characterize the samples prepared by three different technics and comparatively research
their interface feature. 相似文献
11.
Tieping Cao Yuejun Li Changhua Wang Liming Wei Changlu Shao Yichun Liu 《Journal of Sol-Gel Science and Technology》2010,55(1):105-110
Combining the versatility of electrospinning technique and hydrothermal growth of nanostructures enabled the fabrication of
hierarchical CeO2/TiO2 nanofibrous mat. The as-prepared hierarchical heterostructure consisted of CeO2 nanowalls growing on the primary TiO2 nanofibers. Interestingly, not only were secondary CeO2 nanowalls successfully grown on TiO2 nanofibers substrates, but also the CeO2 nanowalls were uniformly distributed without aggregation on TiO2 nanofibers. The photocatalytic studies suggested that the CeO2/TiO2 heterostructures showed enhanced photocatalytic efficiency compared with bare TiO2 nanofibers under UV light irradiation. 相似文献
12.
Junseo Choi Ji-Young Ban Suk-Jin Choung Jinsoo Kim Haznan Abimanyu Kye Sang Yoo 《Journal of Sol-Gel Science and Technology》2007,44(1):21-28
Mesoporous TiO2/γ-Al2O3 composite granules were prepared by combining sol–gel/oil-drop method, using various titania solution. The product granules
can be used as a photocatalyst or adsorbent in moving, fluidized bed reactors. The phase composition and pore structure of
the granules can be controlled by calcination temperature and using different titania solution. In the photocatalysis of NH3 decomposition, TiO2/γ-Al2O3 granules using Degussa P25 powder treated thermally at 450 °C showed the highest catalytic ability. However, TiO2/γ-Al2O3 granules using titania made by hydrothermal method had comparable performance in NH3 decomposition. 相似文献
13.
14.
SiO2/TiO2 hybrid nanofibers were prepared by electrospinning and applied for photocatalytic degradation of methylene blue (MB). The phase structure, specific surface area, and surface morphologies of the SiO2/TiO2 hybrid nanofibers were characterized through thermogravimetry (TG), X-ray diffraction (XRD) analysis, Brunauer–Emmett–Teller (BET) analysis, scanning electron microscopy (SEM), etc. XRD measurements indicated that doping of silica into TiO2 nanofibers can delay the phase transition from anatase to rutile and decrease the grain size. SEM and BET characterization proved that silica doping can remarkably enhance the porosity of the SiO2/TiO2 hybrid nanofibers. The MB adsorption capacity and photocatalytic activity of the SiO2/TiO2 hybrid nanofibers were distinguished experimentally. It was found that, although increased silica doping content could enhance the MB adsorption capacity, the intrinsic photocatalytic activity gradually dropped. The SiO2 (10 %)/TiO2 composite nanofibers exhibited the highest MB degradation rate, being superior to SiO2 (20 %)/TiO2 or pure TiO2. 相似文献
15.
Shuai Yuan Shinichi Kawasaki Kohsuke Mori Hiromi Yamashita 《Research on Chemical Intermediates》2008,34(4):331-337
Fluorine-modified TiO2 nan oparticles were synthesized by introducing TiF4 as a fluorine source either before or after the sufficient hydrolysis and condensation of Ti(OEt)4. The photocatalytic activity of the fluorine-modified catalysts was found to be greatly affected by the fluorine position
in TiO2 nanoparticles. When TiF4 and Ti(OEt)4 hydrolyzed with synchronization, the fluorine tended to be doped in the lattice. The formation of Ti3+ defects could result in charge recombination in bulk and bring down the photocatalytic activity. In contrast, if TiF4 was introduced after the sufficient hydrolysis and condensation of Ti(OEt)4. Ti−F bonds could exist mainly on the TiO2 particles surface, which not only prevented the growth of anatase crystals but also facilitated the transfer of organic compounds
from solution to catalyst surface by reducing the hydrophilic properties. 相似文献
16.
Radina Kralchevska Maria Milanova Petya Kovacheva Jovo Kolev Georgi Avdeev Dimitar Todorovsky 《Central European Journal of Chemistry》2011,9(6):1027-1038
Microcomposites consisting of TiO2 (or Ce-doped TiO2) and ThO2 (0.5–2% of the TiO2 mass) are produced by sol-gel synthesis of TiO2 in presence of ThO2. X-ray diffraction study reveals the effects of ThO2 (compared to the ThO2-free TiO2, obtained by the same method) on the anatase interplanar distances, crystallites size and phase composition. The photocatalytic
tests in presence of the composites under UV irradiation reveal an increase of the Malachite Green degradation rate constant.
The effect depends on the Th relative content, temperature of annealing of the catalyst and addition of other doping agent.
The highest photocatalytic activity is observed for TiO2 obtained at 550°C and containing 1% ThO2. The composite exhibits activity in dark, also. The presence of Ce4+ ions is not an obligatory requirement for the realization of the ThO2 effect. The reported results suggest that the radioactivity of the Th and/or its decay products is one of the main factors
responsible for the increased photocatalytic activity of TiO2.
相似文献
17.
E. Ramírez-Meneses A. García-Murillo F. de J. Carrillo-Romo R. García-Alamilla P. Del Angel-Vicente J. Ramírez-Salgado P. Bartolo Pérez 《Journal of Sol-Gel Science and Technology》2009,52(2):267-275
Titania thin films were synthesized by sol–gel dip-coating method with metallic Ni nanoparticles synthesized separately from
an organometallic precursor Ni(COD)2 (COD = cycloocta-1,5-diene) in presence of 1,3-diaminopropane as a stabilizer. Titania was obtained from a titanium isopropoxide
precursor solution in presence of acetic acid. A Ni/TiO2 sol system was used to coat glass substrate spheres (6, 4 and 3 mm diameter sizes), and further heat treatment at 400 °C
was carried out to promote the crystallization of titania. XRD analysis of the TiO2 films revealed the crystallization of the anatase phase. Transmission Electron Microscopy (TEM) and High Resolution TEM studies
of Ni nanoparticles before mixing with the TiO2 solution revealed the formation of Ni nanostructures with an average size of 5–10 nm. High-angle annular dark-field images
of the Ni/TiO2 system revealed well-dispersed Ni nanoparticles supported on TiO2 and confirmed by AFM analysis. The photocatalytic activity of the Ni/TiO2 films was evaluated in hydrogen evolution from the decomposition of ethanol using a mercury lamp for UV light irradiation.
Titania films in presence of Ni nanoparticles show higher efficiency in their photocatalytic properties in comparison with
TiO2. 相似文献
18.
H. Y. He 《Research on Chemical Intermediates》2010,36(2):155-161
The photocatalytic activity of S-doped TiO2 powder depends on the S content. To synthesize S-doped TiO2 powders with high S content, solvothermal processes were used in this work. The S-doped TiO2 powder contains 2.0 M% sulfur and has an absorption edge of 460 nm (2.7 eV). The pure TiS2 powder also synthesized by a solvothermal process has an absorption edge of 595 nm (2.08 eV) and broad absorption above 595 nm.
The photocatalysis experiments indicate that the degradation of methyl orange is associated with the light adsorption edge.
The photocatalytic activity is much larger for the pure TiS2 powder than for partially S-doped TiO2 powder. 相似文献
19.
Visible-light-driven photocatalytic degradation of microcystin-LR by Bi-doped TiO<Subscript>2</Subscript> 总被引:1,自引:0,他引:1
Jing Yang Deng-Xia Chen An-Ping Deng Ying-Ping Huang Chun-Cheng Chen 《Research on Chemical Intermediates》2011,37(1):47-60
Bi-doped nano-crystalline TiO2 (Bi–TiO2) has been synthesized by sonocrystallization at low temperature. The Bi–TiO2 materials have narrower bandgaps than pristine TiO2, which endow them with significant visible light absorption. Accordingly, these materials had enhanced photocatalytic activity
in the degradation of organic dye pollutants and the cyanotoxin microcystin-LR (MC-LR) under visible irradiation. It was found
that degradation of MC-LR is rather efficient. After irradiation with visible light for 12 h the original MC-LR was removed
completely, and 78% of the organic carbon was mineralized into CO2 after irradiation for 20 h. The hydroxyl radical (·OH) is the major active species responsible for the degradation reaction.
Identified intermediates primarily originate from attack of ·OH radicals on the double bonds between C4 and C5 (C6 and C7)
of Adda and the ethylenic bond of Mdha in MC-LR. Some peptide bonds are also broken with longer irradiation time. 相似文献
20.
Yu. V. Mikushina A. B. Shishmakov V. V. Matskevich N. A. Zhuravlev O. V. Koryakova V. G. Kharchuk L. A. Petrov 《Russian Journal of Inorganic Chemistry》2008,53(10):1557-1560
Silica/titania binary xerogels were prepared by joint hydrolysis of the ingredients. Gels of various compositions were characterized by 1H NMR spectroscopy, IR spectroscopy, and thermogravimetry. The spectral characteristics of binary systems differ considerably from mere superposition of the spectra of the two constituent compounds and the spectrum of a mechanical mixture. A feasibility was demonstrated for controlling the acid properties of binary oxide gels via varying the component mole ratio. 相似文献