共查询到20条相似文献,搜索用时 15 毫秒
1.
Juhong Zhu Dong Yang Jiaqing Geng Daimei Chen Zhongyi Jiang 《Journal of nanoparticle research》2008,10(5):729-736
In order to efficiently use the visible light in the photocatalytic reaction, a novel bamboo-like CdS/TiO2 nanotubes composite was prepared by a facile chemical reduction method, in which CdS nanoparticles located in the TiO2 nanotubes. The composition and structure of this nanocomposite were characterized by TEM, HRTEM, XRD, XPS, FTIR and UV-vis
spectroscopy. This CdS/TiO2 nanotubes composite exhibited much higher visible-light photocatalytic activity for the degradation of methylene blue than
pure TiO2 nanotubes and CdS nanoparticles, and the highest photodegradation efficiency after 6 h irradiation can reach 84.5%. It is
inferred that the unique structure of CdS/TiO2 nanotubes composites acts an important role for the improvement of their photocatalytic activity. 相似文献
2.
Synthesis,characterization of Cr-doped TiO<Subscript>2</Subscript> nanotubes with high photocatalytic activity 总被引:1,自引:0,他引:1
Shoumin Zhang Yanyan Chen Ying Yu Haihong Wu Shurong Wang Baolin Zhu Weiping Huang Shihua Wu 《Journal of nanoparticle research》2008,10(5):871-875
Cr-doped TiO2 nanotubes (Cr/TiO2 NTs) with high photocatalytic activity were prepared by the combination of sol–gel process with hydrothermal treatment. XRD,
TEM and UV–vis DRS techniques were employed for microstructural characterization. TEM images show that Cr/TiO2 NTs are in good tubular structure and have diameter of about 10 nm. The Cr doping induces the shift of the absorption edge
to the visible light range and the narrowing of the band gap. The photocatalytic experiment reveals that the photocatalytic
performance of TiO2 NTs can be improved by the doping of chromium ions. 相似文献
3.
A kind of novel ZnSnO3/SnO2 hollow urchin nanostructure was synthesized by a facile, eco-friendly two-step liquid-phase process. The structure, morphology, and composition of samples were characterized using X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), and nitrogen adsorption–desorption techniques. The results revealed that many tiny needle-like SnO2 nanowires with the average diameter of 5 nm uniformly grew on the surface of the ZnSnO3 hollow microspheres and the ZnSnO3/SnO2 hollow urchin nanostructures with different SnO2 content also were successfully prepared. In order to comprehend the evolution process of the ZnSnO3/SnO2 hollow urchin nanostructures, the possible growth mechanism of samples was illustrated via several experiments in different reaction conditions. Moreover, the gas-sensing performance of as-prepared samples was investigated. The results showed that ZnSnO3/SnO2 hollow urchin nanostructures with high response to various concentration levels of acetone enhanced selectivity, satisfying repeatability, and good long-term stability for acetone detection. Specially, the 10 wt% ZnSnO3/SnO2 hollow urchin nanostructure exhibited the best gas sensitivity (17.03 for 50 ppm acetone) may be a reliable biomarker for the diabetes patients, which could be ascribed to its large specific surface area, complete pore permeability, and increase of chemisorbed oxygen due to the doping of SnO2. 相似文献
4.
S. Pekárek 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2008,50(2):171-175
Non-thermal electrical discharges, such as corona discharge are apart of the
source of ozone, charged, and excited species and acoustic noise also the
source of electromagnetic radiation of different wavelengths. The important
component of this radiation from the standpoint of photocatalyst activation
is the ultraviolet radiation. We studied the role of UV radiation on corona
discharge ozone production by placing the titanium dioxide photocatalyst
into the discharge region. We used hollow needle to mesh DC corona discharge
at atmospheric pressure with TiO2 globules on the mesh. The discharge
was enhanced by the flow of air through the needle. We found that for the
needle biased negatively addition of TiO2 photocatalyst on the mesh
electrode drastically increases discharge ozone production as well as the
ozone production yield. These quantities are also influenced by the mass of
the used photocatalyst and its distribution in the discharge chamber. 相似文献
5.
6.
TiO2 Nano rods can be used as dye-sensitized solar cells, various sensors and photocatalysts. These nanorods are synthesized by
a hydrothermal corrosion process in NaOH solution at 200°C using TiO2 powder as the source material. In the present work, the synthesis of TiO2 nanorods in anatase, rutile and Ti7O13 phases and synthesis of TiO2 nanorods by incorporating SiO2 dopant, using the sol–gel method and alkaline corrosion are reported. The morphologies and crystal structures of the TiO2 nanorods are characterized using field emission scanning electron microscopy (FE-SEM), atomic force microscopy (AFM) and
X-ray diffraction (XRD) study. The obtained results show not only an aggregation structure at high calcination temperatures
with spherical particles but also Ti–O–Si bonds having four-fold coordination with oxygen in SiO4 − . 相似文献
7.
T. V. Sviridova L. Yu. Sadovskaya A. I. Kokorin E. A. Konstantinova V. E. Agabekov D. V. Sviridov 《Russian Journal of Physical Chemistry B, Focus on Physics》2017,11(2):348-353
The thin-film photocatalysts TiO2/MoO3 and TiO2/MoO3:V2O5 obtained by a combination of sol–gel and sintering techniques were studied using the photooxidation of probing dyes, EPR spectroscopy, X-ray diffraction analysis, and electron microscopy. It was shown that due to charge accumulation caused by UV irradiation, these photocatalysts retain their oxidative activity and ability for self-sterilization in the dark for a long time after irradiation was terminated (up to 5 h for TiO2/MoO3:V2O5). 相似文献
8.
Chun-Han Chen Chang-Ning Huang Shuei-Yuan Chen Pouyan Shen 《Journal of nanoparticle research》2011,13(9):3683-3692
TiO2 nanoparticles with enhanced solid solution of Cr up to 16 wt% in polymorphs of rutile, anatase, brookite, α-PbO2-type, and occasionally baddeleyite-type were synthesized via pulse laser ablation on ceramic TiO2 target dissolved with Cr2O3 or clamped Cr/Ti plates in air. Analytical electron microscopic observations indicated these nanocondensates have prevalent
crystallographic shear (CS) along specific planes to form superstructures. The rutile type typically shows (100) and (010)
CS besides the conventional ones rotating about the [111] zone axis as reported for ambient samples. The CS planes are parallel
to (001) for anatase, (001) and ([`1] \overline{1} 10) for brookite, whereas (001) and {1[`3] \overline{3} 1} for the α-PbO2-type TiO2 with varied extent of Cr dissolution. Surface modification, as a result of Cr dissolution and/or internal stress, was observed
for all the polymorphs. 相似文献
9.
Ni12P5 hollow microspheres were prepared by a simple mixed cetyltrimethyl ammonium bromide/sodium dodecyl sulfate surfactant-assisted hydrothermal route. The as-prepared Ni12P5 microstructures were characterized by X-ray powder diffraction (XRD), field emission scanning electron microscopy (FE-SEM), and transmission electron microscopy (TEM). It was interesting to find that cetyltrimethyl ammonium bromide/sodium dodecyl sulfate could form a micro-reactor by the mixed micelles in the aqueous solution, which served as a soft template for Ni12P5 hollow microspheres with a diameter of 2~6 μm. Moreover, the as-prepared Ni12P5 hollow microspheres exhibited a good photocatalytic degradation activity for some organic dyes (such as Rhodamine B, Methylene Blue, Pyronine B, and Safranine T), and the degradation ratio could achieve more than 80%. 相似文献
10.
Shuaiqi Gong Zhengjun Jiang Sheng Zhu Jinchen Fan Qunjie Xu Yulin Min 《Journal of nanoparticle research》2018,20(11):310
In this paper, an efficient strategy for the synthesis of graphene nanobelt-titanium dioxide/graphitic carbon nitride (graphene-TiO2/g-C3N4) heterostructure photocatalyst was applied to fabricate a kind of visible-light-driven photocatalyst. The heterostructure shows higher absorption edge towards harvesting more solar energy compared with pure TiO2 and pure g-C3N4 respectively. Furthermore, the as-prepared graphene-TiO2/g-C3N4 heterostructure can show enhanced photocatalytic activity under visible-light irradiation. These outstanding performances of photocatalytic activities for graphene-TiO2/g-C3N4 composites can be attributed to the heterojunction interfaces which can separate the electron-hole pairs and impede the recombination of electrons and holes more efficiently. This study conclusively demonstrates a facile and environmentally friendly new strategy to design highly efficient graphene-TiO2/g-C3N4 heterostructure photocatalytic materials for potential applications under visible-light irradiation. 相似文献
11.
Two sets of samples of SnO2/In2O3/TiO2 system have been fabricated with different concentrations of component materials. In the first set TiO2 with rutile structure was used, while in the second set it has the structure of anatase. Thin films (up to 50 nm) of obtained
mixtures were deposited. Their sensitivity and selectivity with respect to methane (CH4) were studied. Nanostructure on the
basis of 70%SnO2 — 10%In2O3 — 20%TiO2(anatase) exhibits sufficient sensitivity to methane. 相似文献
12.
Terry A. Egerton Lorna M. Kessell Ian R. Tooley Liwei Wang 《Journal of nanoparticle research》2007,9(2):251-260
Photogreying, the change in brightness on UV irradiation in the absence of oxygen, of TiO2 nanoparticulate dispersions is shown to depend on the nature of the liquid, consistent with a surface reaction. Measurements
on a series of TiO2 particles (mainly 75×10 nm) dispersed in, e.g., alkyl benzoate correlate well with those on the same TiO2’s dispersed in a second liquid (e.g. propan-2-ol). Photogreying in propan-2-ol is paralleled by photocatalytic-oxidation
activity, indicating a common origin – UV-generation of charge carriers. Further, photogreying parallels Ti3+ formation. Hence, although appearance and the visible spectra of photogreyed particles both differ from those of Ti3+ in ≤10 nm colloidal TiO2, we suggest that photogreying is caused by capture of UV excited electrons to form Ti3+. Surface treatment reduces photogreying, and we speculate that differences between uncoated samples reflect differences in
the number of potentially reducible Ti’s. 相似文献
13.
The controllable synthesis and characterization of novel thermally stable silver-based particles are described. The experimental approach involves the design of thermally stable nanostructures by the deposition of an interfacial thick, active titania layer between the primary substrate (SiO2 particles) and the metal nanoparticles (Ag NPs), as well as the doping of Ag nanoparticles with an organic molecule (Congo Red, CR). The nanostructured particles were composed of a 330-nm silica core capped by a granular titania layer (10 to 13 nm in thickness), along with monodisperse 5 to 30 nm CR-Ag NPs deposited on top. The titania-coated support (SiO2/TiO2 particles) was shown to be chemically and thermally stable and promoted the nucleation and anchoring of CR-Ag NPs, which prevented the sintering of CR-Ag NPs when the structure was exposed to high temperatures. The thermal stability of the silver composites was examined by scanning electron microscopy (SEM) and high-resolution transmission electron microscopy (HRTEM). Larger than 10 nm CR-Ag NPs were thermally stable up to 300 °C. Such temperature was high enough to destabilize the CR-Ag NPs due to the melting point of the CR. On the other hand, smaller than 10 nm Ag NPs were stable at temperatures up to 500 °C because of the strong metal-metal oxide binding energy. Energy dispersion X-ray spectroscopy (EDS) was carried out to qualitatively analyze the chemical stability of the structure at different temperatures which confirmed the stability of the structure and the existence of silver NPs at temperatures up to 500 °C. 相似文献
14.
Self-cleaning and anti-bacterial activities of the photo-catalyst titanium dioxide make it a superior compound for use in the ceramics and glass industry. In order to achieve high self-cleaning efficiency for building products, it is important that Titania is present as anatase phase. Moreover, it is desirable that the particle sizes are in Nano-range, so that a large enough surface area is available for enhanced catalytic performance. In the present paper, Cobalt and Nickel co-doped (4%mol Ni and 4%mol Co doped TiO2) and un-doped TiO2 Nano powders have been prepared by sol–gel technique. They were calcined at the temperatures in the range of 475–1075 °C. Ni/Co co-doped TiO2 postponed the anatase to rutile transformation of TiO2 by about 200–300°C, such that before calcination at 775°C, no rutile was detected for 4 mol% Ni/Co co-doped TiO2. A systematic decreasing on crystallite size and increasing on specific surface area of Ni/Co co-doped TiO2 were observed. Photo-catalytic activity of anatase polymorph was measured by the decomposition rate of methylene blue under visible light. The results showed enhanced catalysis under visible light for Ni/Co co-doped TiO2 as compared to pure TiO2. The enhanced performance was attributed to surface chemistry change associated with a slight shift in the band gap. Depending on the temperatures ranging from 475 to 1075 °C, band gap energy of Ni and Co doped TiO2 crystals decreased. For all samples there is a general reduction of the band gap energy from 3.00 to 2.96 eV. 相似文献
15.
Hierarchical Na2FeP2O7 spheres with nanoparticles were successfully fabricated by a facile spray drying method. A relatively low drying temperature was introduced in order to form a carbon layer on the surface. As a cathode material for sodium-ion batteries, it delivered a reversible capacity of 84.4 mAh g?1 at 0.1 C and showed excellent cycling and rate performance (64.7 mAh g?1 at 5 C). Furthermore, a full sodium battery was fabricated using SP-Na2FeP2O7 as the cathode and hard carbon as the anode, suffering almost no capacity loss after 400 cycles at 1 C. Due to its superior electrochemical property and the low materials cost, Na2FeP2O7 is becoming a promising cathode material for large-scale energy storage systems. 相似文献
16.
Luca Giacomo Bettini Maria Vittoria Diamanti Maurizio Sansotera Maria Pia Pedeferri Walter Navarrini Paolo Milani 《Journal of nanoparticle research》2016,18(8):238
Anatase/rutile mixed-phase titanium dioxide (TiO2) photocatalysts in the form of nanostructured powders with different primary particle size, specific surface area, and rutile content were produced from the gas-phase by flame spray pyrolysis (FSP) starting from an organic solution containing titanium (IV) isopropoxide as Ti precursor. Flame spray-produced TiO2 powders were characterized by means of X-ray diffraction, Raman spectroscopy, and BET measurements. As-prepared powders were mainly composed of anatase crystallites with size ranging from 7 to 15 nm according to the synthesis conditions. TiO2 powders were embedded in a multilayered fluoropolymeric matrix to immobilize the nanoparticles into freestanding photocatalytic membranes. The photocatalytic activity of the TiO2-embedded membranes toward the abatement of hydrosoluble organic pollutants was evaluated employing the photodegradation of rhodamine B in aqueous solution as test reaction. The photoabatement rate of best performing membranes significantly overcomes that of membranes produced by the same method and incorporating commercial P25-TiO2. 相似文献
17.
A fast and economical route based on an efficient microwave-induced solid-state process has been developed to synthesize metastable
TiO2(B) nanobelts with widths of 30–100 nm and lengths up to a few micrometers on a large scale. This new method reduces the synthesis
time for the preparation of TiO2(B) nanobelts to less than half an hour, allowing the screening of a wide range of reaction conditions for optimizing and
scaling up the production and facilitating the formation of metastable phase TiO2(B). The as-formed TiO2(B) nanobelts exhibit enhanced lithium-storage performances, compared with the TiO2(B) product obtained by the conventional heating. This study provides a new way for large-scale industrial production of high-quality
metastable TiO2(B) nanostructures. The products were characterized by X-ray diffraction, scanning electron microscopy, transmission electron
microscopy, and Raman spectroscopy. 相似文献
18.
Although Gd2O3 (gadolinia) nanoparticle is the subject of intense research interest due to its magnetic property as well as controllable
emission wavelengths by doping of various lanthanide ions, it is known to be difficult to prepare monodisperse crystalline
gadolinia nanoparticles because it requires high temperature thermal annealing process to enhance the crystallinity. In this
article, we demonstrate the synthesis of hollow nanoparticles of crystalline Gd2O3 by employing poly(N-vinylpyrrolidone) (PVP) to stabilize the surface of Gd(OH)CO3·H2O nanoparticles and to successively form SiO2 shell as a protecting layer to prevent aggregation during calcinations processes. Silica shells could be selectively removed
after calcinations by a treatment with basic solution to give hollow nanoparticles of crystalline Gd2O3. The formation mechanism of hollow nanoparticles could be suggested based on several characterization results of the size
and shape, and crystallinity of Gd2O3 nanoparticles by TEM, SEM, and XRD. 相似文献
19.
Xiaona Zhao Pei Wu Dingze Lu Pengfei Fang Min Liu Zhouhai Qian 《Journal of nanoparticle research》2017,19(9):325
CeO2 and Fe2O3 co-modified titanate nanosheet (Fe2O3/CeO2@TNS) was prepared by one-pot hydrothermal method; the photocatalyst exhibited large surface area with CeO2 and Fe2O3 particles well dispersed on the surface. The results of XRD, BET, and Raman proved that the CeO2 and Fe2O3 introduced in the TNS influenced its structure evolution from 3D to 2D. The modification resulted in a shift of the absorption edge toward a longer wavelength and the band gap reduced to 2.87 eV. The three-component systems performed excellent photocatalytic activity and cycle stability on phenol and methyl blue (MB) solution under sunlight; nearly total phenol and MB were degraded in dozens of minutes. And the reaction rate constant (K) of Fe2O3/CeO2@TNS on phenol degradation was 1.77, 3.25, 4.88, and 13-fold of Fe2O3@TNS, CeO2@TNS, bare TNS, and P25, respectively. The enhanced photocatalytic activity could be ascribed to the efficient separation of photogenerated pairs through the formation of tandem n-n-n heterojunction among the three-component systems. This work will be useful for the design of other tandem n-n-n heterojunction photocatalytic systems for application in energy conversion and environmental remediation. 相似文献
20.