共查询到20条相似文献,搜索用时 15 毫秒
1.
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
2.
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
3.
Nanostructures TiO2–SiO2 photocatalysts were successfully synthesized using the sol-gel method, hydro-calcination, co-precipitation and room-temperature solid-phase synthesis technology. X-ray powder diffraction pattern (XRD), Fourier transform infrared spectrum (FTIR), photoluminescence (PL) spectra, thermal analyses (TG–DTA), scanning electron micrographs (SEM), X-ray photoelectron spectroscopy (XPS), and UV-Vis diffuse reflectance spectroscopy (UV-Vis DRS) were used to characterize the as-synthesized catalysts. Photocatalytic performances of the catalysts were evaluated by the degradation of methyl orange (MO) under s imulated natural light and the degradation rate of MO is 97.2%. The composites showed a good stability: after five recycling runs there are no significant decreases in the photocatalytic activity. The photodegradation of methylene blue, rhodamine B, methyl violet, naphthol green B, basic fuchsin, malachite green, and methyl red were also tested, and the degradation rate of dyes could reach over 94.2 %. A possible mechanism for the photocatalysis with the TiO2–SiO2 was proposed. 相似文献
4.
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
5.
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
6.
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
7.
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
8.
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
9.
10.
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
11.
Feng Tao Yingzhong Shen Yanyu Liang Hulin Li 《Journal of Solid State Electrochemistry》2007,11(6):853-858
A novel composite of Co(OH)2 and TiO2 nanotubes was synthesized by a chemical precipitation method. Co(OH)2/TiO2 nanotube composites and its microstructure were characterized by transmission electron microscopy (TEM), X-ray diffraction
pattern (XRD). The electrochemical capacitance performance of this composite was investigated by cyclic voltammetry and charge–discharge
tests with a three-electrode system in 6 M KOH solution. We synthesized different weight ratios of Co(OH)2/TiO2 nanotubes, a maximum specific capacitance of 229 F/g was obtained for the composite. Based on these tests, we propose that
TiO2 nanotubes provide the three-dimensional nanotube network structure for the composite and make the Co(OH)2 dispersed. For these reasons, the TiO2 nanotubes used as a framework for Co(OH)2 improve the utilization of Co(OH)2 greatly. 相似文献
12.
C. T. Yu C. F. Wang T. Y. Chen Y. T. Chang 《Journal of Radioanalytical and Nuclear Chemistry》2008,277(2):337-345
A TiO2/monazite photocatalyst was prepared by embedding TiO2 nanoparticles into a monazite substrate surface. TiCl4 hydrolysis/citric acid chelating procedure under acidic conditions were used to synthesize the nanophase TiO2 particles. The anatase TiO2/monazite photocatalyst surface area, morphology, crystalline and elemental concentrations were characterized using Brunauer-Emmett-Teller
(BET) method, scanning electron microscopy (SEM), X-ray diffraction (XRD), and inductively coupled plasma-atomic emission
spectrometry (ICP-AES). Monazite contains a large amount of Ce-, La-, Nd- and Th-PO4 compounds; it has been known as a natural mineral material with minor radioactivity. TiO2-CeO2 composite is a kind of radiation sensitive photocatalyst in which the radiations of thorium nuclides give energy to trigger
TiO2 and cerium ions which play an energy absorber with charge separator. The result showed that methylene blue and phenol were
spontaneously photocatalytic decomposed by TiO2/monazite composite even in a dark environment. A synergistic effect was also examined with applied exterior UV or 60Co irradiation. A hybrid mechanism is proposed; according by the radioluminescence (RL) from excited Ce ion by γ-radiation
soliciting CeO2/TiO2 heterojunction (HJ). This seems to be a possible mechanism to explain this self-activated photo-catalytic behavior. 相似文献
13.
Nemat Tahmasbi Somayeh Madmoli Parisa Farahnak Shahram Barzegar Hamze Moayeri 《Russian Journal of Applied Chemistry》2017,90(9):1488-1493
In the paper cesium tungstate nanofibers for the first time have been fabricated successfully by a simple electrospinning technique followed by heat treatment. The cesium tungstate nanofibers have been characterized by XRD, SEM, and FTIR techniques. The results indicated the morphology and quality of the annealed electrospun samples are strongly dependent on the citric acid content within electrospinning solution. It is found with increasing the citric acid content from 7 to 22% the samples morphology changed from a particle structure to a fibrous structure. The average diameter of nanofibers was ~350 nm. XRD analysis reveals that all of the samples have good crystallinity with the same diffraction peaks that can be indexed to the tetragonal phase of Cs2W3O10. Furthermore, the photocatalyst properties of cesium tungstate has not been reported to date. In the work the synthesized Cs2W3O10 nanofibers were found to exhibit photocatalytic performance in the photodegradation of RhB aqueous solution used as a pollutant model. 相似文献
14.
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
15.
Jingfei Luan Hongling Cai Xiping Hao Jibiao Zhang Guoyou Luan Xiaoshan Wu Zhigang Zou 《Research on Chemical Intermediates》2007,33(6):487-500
Bi2FeVO7 was prepared by a solid-state reaction technique for the first time and the structural and photocatalytic properties of Bi2FeVO7 were studied. The results shows that this compound crystallized in the tetragonal crystal system with space group I4/mmm.
Moreover, the band gap of Bi2FeVO7 was estimated to be about 2.22(6) eV. For the photocatalytic water splitting reaction, H2 or O2 evolution was observed from pure water with Bi2FeVO7 as the photocatalyst by ultraviolet light irradiation. Degradation of aqueous methylene blue (MB) dye by photocatalytic way
over this compound was further studied under visible light irradiation. Bi2FeVO7 shows higher catalytic activity compared to TiO2 (P-25) for MB photocatalytic degradation under visible light irradiation. Complete removal of aqueous MB was realized after
visible light irradiation for 170 min with Bi2FeVO7 as the photocatalyst. The reduction of the total organic carbon (TOC) and the formation of inorganic products, SO
4
2−
and NO
3
−
revealed the continuous mineralization of aqueous MB during the photocatalytic course. 相似文献
16.
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
17.
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
18.
So-Eun Kim Youngjong Kang Shiao-Wei Kuo Changwoon Nah Kwang-Un Jeong 《Journal of Sol-Gel Science and Technology》2011,60(2):206-213
Epitaxially grown titanium dioxide (TiO2) nanofibers embedding single crystalline TiO2 nanowires (NWs) were successfully fabricated by electropinning poly(vinyl pyrrolidone)/ethanol solutions mixed with hydrothermally
synthesized TiO2 NWs and titanium isopropoxide precursors and subsequently calcinating the electrospun nanofibers. Utilizing scanning electron
microscopy (SEM) and transmission electron microscopy (TEM), the morphologies of TiO2 NWs and nanofibers were investigated. High resolution TEM (HR-TEM) and selected area electron diffraction (SAED) allowed
us to indentify the fact that, during the calcination process under the optimized condition, titanium isopropoxide precursors
were epitaxially crystallized on the surface of single crystalline TiO2 NWs. Based on the X-ray diffraction (XRD) experiments, it was also realized that the crystalline structure of hydrothermally
synthesized TiO2 NWs and epitaxially crystallized TiO2 nanofibers is anatase and that TiO2 composite nanofibers embedding TiO2 NWs exhibited a higher crystallinity than the pristine TiO2 nanofibers. Additionally, ultraviolet visible (UV–Vis) spectra of nanofibers indicated that optical properties of TiO2 nanofibers can be tuned by introducing the single crystalline TiO2 NWs. 相似文献
19.
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
20.
María Luisa Ojeda Monserrat Bizarro Antonio Campero 《Journal of Sol-Gel Science and Technology》2011,60(2):108-115
Nanostructured TiO2 films were synthesized by a modified sol–gel method using Pluronics P-123 (EO20PO70EO20) as templating agent, titanium n-butoxide [Ti(OC4H9)4] as inorganic precursor, and ammonium fluoride (NH4F) as the source of N and F dopant atoms in order to prepare sols of x(NF) TiO2 (x=2, 5, 10, 20 wt%). The thin film preparation was made by spin coating, followed by calcination at 400 °C. The as-prepared
TiO2 and xNF-TiO2 films were characterized by XRD, Raman spectroscopy, FTIR, TGA-DTA, SEM, UV–Vis diffuse reflectance spectroscopy and EPR.
XRD and Raman spectroscopy show that the crystalline structure of these samples consists exclusively of the anatase phase.
The band gap (E
g
) values for the doped 10 and 20 NF-TiO2 film systems were found to be significantly smaller than those corresponding to the rest of the other TiO2 films. The photocatalytic properties of these films are investigated by following the degradation of methyl orange in aqueous
solution under UV irradiation. The photodecomposition is mainly a direct function of the amount of NF present in the TiO2 matrix. The 20NF-TiO2 sample shows the highest activity of all the samples studied. 相似文献