共查询到20条相似文献,搜索用时 31 毫秒
1.
Wei Xie Xinyan Xiao Yichao Zhao Weiping Zhang 《Journal of Coatings Technology and Research》2017,14(5):1147-1158
TiO2/MoS2 composite was encapsulated by hydrophobic SiO2 nanoparticles using a sol–gel hydrothermal method with methyltriethoxysilane (MTES), titanium tetrachloride (TiCl4), and molybdenum disulfide (MoS2) as raw materials. Then, a novel dual functional composite film with hydrophobicity and photocatalytic activity was fabricated on a glass substrates via the combination of polydimethylsiloxane adhesives and hydrophobic SiO2@(TiO2/MoS2) composite particles. The influence of the mole ratios of MTES to TiO2/MoS2 (M:T) on the wettability and photocatalytic activity of the composite film was discussed. The surface morphology, chemical compositions, and hydrophobicity of the composite film on the glass substrate were investigated by scanning electron microscopy, transmission electron microscopy, X-ray powder diffraction, Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, and water contact angle (water CA) measurements. The results indicated that the composite film exhibited stable superhydrophobicity and excellent photocatalytic activity for degradation of methyl orange (MO) even after five continuous cycles of photocatalytic reaction when M/T was 7:1. The water CA and degradation efficiency for MO remained at 154° and 94%, respectively. Further, the composite film showed a good non-sticking characteristic with the water sliding angle (SA) at about 4°. The SiO2@(TiO2/MoS2) composite consisting of hydrophobic SiO2 nanoparticles and TiO2/MoS2 heterostructure could provide synergistic effects for maintaining long-term self-cleaning performance. 相似文献
2.
TiO2 thin and thick films promoted with platinum and organic sensitizers including novel perylene diimide dyes (PDI) were prepared
and tested for carbon dioxide reduction with water under visible light. TiO2 films were prepared by a dip coating sol–gel technique. Pt was incorporated on TiO2 surface by wet impregnation [Pt(on).TiO2], or in the TiO2 film [Pt(in).TiO2] by adding the precursor in the sol. When tris (2,2′-bipyridyl) ruthenium(II) chloride hexahydrate was used as sensitizer,
in addition to visible light activity towards methane production, H2 evolution was also observed. Perylene diimide derivatives used in this study have shown light harvesting capability similar
to the tris (2,2′-bipyridyl) ruthenium(II) chloride hexahydrate. 相似文献
3.
E. I. Papaioannou S. Souentie F. M. Sapountzi A. Hammad D. Labou S. Brosda C. G. Vayenas 《Journal of Applied Electrochemistry》2010,40(10):1859-1865
The electrochemical promotion of Pt/YSZ and Pt/TiO2/YSZ catalyst-electrodes has been investigated for the model reaction of C2H4 oxidation in an atmospheric pressure single chamber reactor, under oxygen excess between 280 and 375 °C. It has been found
that the presence of a dispersed TiO2 thin layer between the catalyst electrode and the solid electrolyte (YSZ), results in a significant increase of the magnitude
of the electrochemical promotion of catalysis (EPOC) effect. The rate enhancement ratio upon current application and the faradaic
efficiency values, were found to be a factor of 2.5 and 4 respectively, higher than those in absence of TiO2. This significantly enhanced EPOC effect via the addition of TiO2 suggests that the presence of the porous TiO2 layer enhances the transport of promoting O2− species onto the Pt catalyst surface. This enhancement may be partly due to morphological factors, such as increased Pt dispersion
and three-phase-boundary length in presence of the TiO2 porous layer, but appears to be mainly caused by the mixed ionic-electronic conductivity of the TiO2 layer which results to enhanced O2− transport to the Pt surface via a self-driven electrochemical promotion O2− transport mechanism. 相似文献
4.
Jae-Hyoung Park Yong-Su Seo Hyun-Seung Kim Il-Kyu Kim 《Korean Journal of Chemical Engineering》2011,28(8):1693-1697
The photodegradation of BTEX (benzene, toluene, ethylbenzene and xylene) in a photocatalytic fluidized bed reactor with TiO2/SiO2 was investigated. The TiO2 film was prepared using the sol-gel method and coated onto silica-gel powder. The effects of the superficial gas velocity
and SiO2 size on the photodegradation of BTEX were examined in a fluidized bed reactor. At steady-state operation, above 79, 79, 99,
98, and 98% removal efficiencies were achieved for benzene, toluene, ethylbenzene, m, p-xylene and o-xylene, respectively,
under optimal conditions (2.0 U
mf
of superficial gas velocity and 1.43 of height/diameter ratio). The reaction product such as CO2 was detected and intermediate products such as benzaldehyde, malonic acid, acetaldehyde, and formic acid were identified
from the photocatalytic reaction. Also, small amounts of benzoic acid and benzyl alcohol were found through analyzing the
intermediate species adsorbed on the photocatalysts. The experimental results can lead to the development of an efficient
photocatalytic treatment system that utilizes solar energy and TiO2/SiO2 photocatalysts. 相似文献
5.
C.-H. Lin C.-H. Lee J.-H. Chao C.-Y. Kuo Y.-C. Cheng W.-N. Huang H.-W. Chang Y.-M. Huang M.-K. Shih 《Catalysis Letters》2004,98(1):61-66
TiO2 nanotubes promoted with Pt metal were prepared and tested to be the photocatalytic dehydrogenation catalyst in neat ethanol for producing H2 gas (C2H5OHC3CHO +H2). It was found that the ability to produce H2, the liquid phase product distribution and the catlyst stability of these promoted nano catalysts all depended on the Pt loading and catalyst preparation procedure. These Pt/TiO2 catalysts with TiO2 nanotubes washed with diluted H2SO4 solution produced 1, 2-diethoxy ethane (acetal) as the major liquid phase product, while over those washed with diluted HCl solution or H2O, acetaldehyde was the major liquid phase product. 相似文献
6.
Sedigheh Vaezifar Hossein Faghihian Mahdi Kamali 《Korean Journal of Chemical Engineering》2011,28(2):370-377
Sn/Pt/Na-ZSM-5 was used as catalyst for the dehydrogenation of isobutane, and the effect of SiO2/Al2O3 ratio and the dispersion of Pt nanoparticles on the conversion and product selectivity were studied under atmospheric pressure
at 848 K. The catalysts were characterized by various techniques such as H2 chemisorption, TEM, SEM, EDX, XRD, FT-IR, TG/DTG, elemental analysis by XRF and ICP techniques. Higher dispersion of Pt nanoparticles
in the catalyst with SiO2/Al2O3 ratio of 40 resulted in higher selectivity for isobutene. 相似文献
7.
Ana M. Antolín Sandra Contreras Francesc Medina Didier Tichit 《Topics in Catalysis》2017,60(15-16):1156-1170
Denitration of water was investigated by non-photocatalytic and/or photocatalytic processes (UV-A irradiation at 365 nm) using a mixture of Ag/P25?+?Pt/P25 monometallic catalysts and Ag–Pt(Pt–Ag)/P25 bimetallic catalysts (2 wt% Ag; 4 wt% Pt) prepared by drop-wise wetness impregnation of TiO2 P25 support. In the bimetallic samples, the influences of the Pt precursor (H2PtCl6·6H2O; K2PtCl6) and of the impregnation order of the metallic salts were examined. The highest N2 yield (42.3%) in the non-photocatalytic process was achieved with the Ag/P25?+?Pt/P25 mixture but with ca. 12.6% NO2 ? yield. Photocatalytic activity was enhanced in presence of H2 in comparison to H2-free condition. Ag/P25 is the most active photocatalyst, however high NO2 ? yield is obtained (32.5%). The bimetallic samples exhibit high versatility, being active both in the non-photocatalytic and the photocatalytic processes. Low NO3 ? conversion and high NO2 ? selectivity results were obtained from impregnation of Ag first. In contrast, impregnation of Pt precursor from K2PtCl6 first effectively promoted NO3 ? reduction towards N2 yield of 36% and particularly low NO2 ? yield of 2.7%, due the presence of metallic nanoparticles of different sizes and interaction with TiO2 with a peculiar strong Pt and Ag interaction. Best results obtained in non-photocatalytic and photocatalytic processes are almost similar. 相似文献
8.
Xuejuan Zhao Wei Zhang Shuangjun Chen Jun Zhang Xiaolin Wang 《Journal of Polymer Research》2012,19(5):9862
Composites with enhanced hydrophilicity were prepared by adding TiO2 or SiO2 nanoparticles during the in situ polymerization of methyl methacrylate (MMA) in poly(vinylidene fluoride) (PVDF). The hydrophilicities
of the PVDF/PMMA/TiO2(SiO2) composites generated in this manner were characterized by contact angle measurements and atomic force microscopy (AFM).
The hydrophilicity was dependent on nanoparticle content; it gradually increased with increasing TiO2 (or SiO2) content when the TiO2 (or SiO2) content was no more than 4 wt% of PVDF. A homogeneous dispersion of the TiO2 (or SiO2) nanoparticles in the composite matrix was observed in scanning electron microscope (SEM) images. Based on Fourier transform
infrared (FTIR) spectra and wide angle X-ray diffraction (WAXD) analyses, the crystalline phase composition of PVDF was not
influenced by the addition of TiO2 (or SiO2); PVDF crystallized predominantly in the α phase after in situ polymerization. Nevertheless, the nanoparticles can promote
the formation of the β phase of PVDF in composites; the β-phase content increased with increasing TiO2 content, while it was almost independent of SiO2 content. 相似文献
9.
Woo-Hee Kim Hyungjun Kim Han-Bo-Ram Lee 《Journal of Coatings Technology and Research》2017,14(1):177-183
Thin film optics, based on light interference characteristics, are attracting increasing interest because of their ability to enable a functional color coating for various applications in optical, electronic, and solar industries. Here, we report on the dependence of coloring characteristics on single-layer TiO2 thicknesses and alternating TiO2/Al2O3 multilayer structures prepared by atomic layer deposition (ALD) at a low growth temperature. The ALD TiO2 and Al2O3 thin films were studied at a low growth temperature of 80°C. Then, the coloring features in the single-layer TiO2 and alternating TiO2/Al2O3 multilayers using both the ALD processes were experimentally examined on a TiN/cut stainless steel sheet. The Essential Macleod software was used to estimate and compare the color coating results. The simulation results revealed that five different colors of the single TiO2 layers were shown experimentally, depending on the film thickness. For the purpose of highly uniform pink color coating, the film structures of TiO2/Al2O3 multilayers were designed in advance. It was experimentally demonstrated that the evaluated colors corresponded well with the simulated color spectrum results, exhibiting a uniform pink color with wide incident angles ranging from 0° to 75°. This article advances practical applications requiring highly uniform color coatings of surfaces in a variety of optical coating areas with complex topographical structures. 相似文献
10.
Seung-Joon Yoo Se-Il Lee Dong-Heui Kwak Kwang-Gil Kim Kyung-Jun Hwang Jae-Wook Lee Un-Yeon Hwang Hyung-Sang Park Jong-Ok Kim 《Korean Journal of Chemical Engineering》2008,25(5):1232-1238
Nanosized TiO2 sol synthesized by sol-gel method was successfully coated on the porous red clay tile (PRC tile) with micrometer sized pores.
PRC tile was first coated with a low-firing glaze (glaze-coated PRC tile) and then TiO2 sol was coated on the glaze layer. A low-fired glaze was prepared at various blending ratios with frit and feldspar, and
a blending ratio glazed at 700 °C was selected as an optimum condition. Then TiO2 sol synthesized from TTIP was dip-coated on the glazed layer (TiO2/glaze-coated PRC tile), and it was calcined again at 500 °C. Here, these optimum calcination temperatures were selected to
derive a strong bonding by a partial sintering between TiO2 sol particles and glaze layer. Photocatalytic activity on the TiO2/glaze-coated PRC tile was evaluated by the extent of photocatalytic degradation of methylene blue and acetaldehyde. Methylene
blue with the high concentration of 150 mg/l on the surface of TiO2/glaze-coated PRC tile was almost photodegraded within 5 hours under the condition of average UV intensity of 0.275 mW/cm2, while no photodegradation reaction of methylene blue occurred on the glaze-coated PRC tile without TiO2. Another photocatalytic activity was also evaluated by measuring the extent of photocatalytic degradation of gaseous acetaldehyde.
The photodegradation efficiency in TiO2/glaze-coated PRC tile showed about 77% photocatalytic degradation of acetaldehyde from 45,480 mg/l to 10,536 mg/l after the UV irradiation of 14 hours, but only about 16% in the case of the glaze-coated PRC tile. 相似文献
11.
Junyeong Kim Jeong Yeon Do No-Kuk Park Seung Jong Lee Jin-Pyo Hong Misook Kang 《Korean Journal of Chemical Engineering》2018,35(5):1089-1098
Nano-sized bismuth sulfide (Bi2S3) and titanium dioxide (TiO2) with the orthorhombic and anatase tetragonal structures, respectively, were synthesized for application as catalysts for the reduction of carbon dioxide (CO2) to methane (CH4). Four double-layered dense films were fabricated with different coating sequences—TiO2 (bottom layer)/Bi2S3 (top layer), Bi2S3/TiO2, TiO2/Bi2S3: TiO2 (1 : 1) mix, and Bi2S3: TiO2 (1 : 1) mix/Bi2S3: TiO2 (1 : 1) mix—and applied to the photoreduction of CO2 to CH4; the catalytic activity of the fabricated films was compared to that of the pure TiO2/TiO2 and Bi2S3/Bi2S3 doubled-layered films. The TiO2/Bi2S3 double-layered film exhibited superior photocatalytic behavior, and higher CH4 production was obtained with the TiO2/Bi2S3 double-layered film than with the other films. A model of the mechanism underlying the enhanced photoactivity of the TiO2/Bi2S3 double-layered film was proposed, and it was attributed in effective charge separation. 相似文献
12.
Zhi-Yuan Yang Guang-Yu Shen Yun-Peng He Xiao-Xia Liu Shui-Jin Yang 《Journal of Porous Materials》2016,23(3):589-599
The composite semiconductor photocatalyst TiO2/SiO2 was prepared by template-hydrothermal method using carbon spheres as the template. The structural and optical properties of TiO2/SiO2 were characterized by XRD, SEM, BET, UV–Vis DRS, TG-DTA, PL techniques. The formation of hydroxyl radical on the surface of TiO2/SiO2 was studied with terephthalic acid as the probe molecule, combined with fluorescence technique. The results showed that the specific surface area of TiO2/SiO2 composite was 327.9 m2/g, and the specific surface area of TiO2/SiO2 was larger than that of pure TiO2. Photocatalytic degradation of rhodamine B showed that TiO2/SiO2 composite oxide under visible light illumination 40 min, the degradation rate was 98.6 % and the degradation rate of pure TiO2 was only 11.9 %. The apparent first-order rate constant of TiO2/SiO2 was 33 times that of pure TiO2 and more than 6 times that of P25 when the molar ratio of Ti to Si was 1:1 under visible light irradiation. Moreover, it’s also as much as 5 times that of pure TiO2 and is more than 1 times that of P25 under UV light irradiation 25 min. Based on the experimental results, ·O2 ? and h+ were suggested to be the major active species which was responsible for the degradation reaction. The increased photocatalytic activity of TiO2/SiO2 may be mainly attributed to effectively suppressing the recombination of hole/electron pairs. After the photocatalyst TiO2/SiO2 was reused 5 times, the degradation rate of rhodamine B could reach 89.2 % under visible light irradiation. Moreover, The composite semiconductor photocatalyst TiO2/SiO2 was selective towards the degradation of rhodamine B. 相似文献
13.
Tsuyoshi Ochiai Tomohiro Fukuda Kazuya Nakata Taketoshi Murakami Donald A. Tryk Yoshihiro Koide Akira Fujishima 《Journal of Applied Electrochemistry》2010,40(10):1737-1742
The capabilities of TiO2-coated materials for the inactivation and removal of algae were investigated. As supports for TiO2, non-woven fabric and Ni foam were chosen. To evaluate the ability of noble metal cocatalyst additions to facilitate the
photocatalytic algal inhibition of TiO2-coated materials, Pd nanoparticles were deposited on non-woven fabric-supported TiO2 by photoelectrochemical deposition. The fabric-supported Pd/TiO2 showed higher inhibition activity for algal growth compared to the fabric-supported TiO2 without Pd. In addition, Ni foam-supported TiO2 also showed high inhibition activity, both in laboratory-scale tests and open-air tests. Therefore, TiO2-coated materials with suitable coating methods such as the use of cocatalysts or large surface area can substantially inhibit
algal growth. The ability of the TiO2-coated materials to inhibit algae correlated well with their activity for the photocatalytic decolorization of methylene
blue, suggesting a nonspecific mechanism in the breakdown of cellular structures. 相似文献
14.
Rasoul Khosravi Ahmad Zarei Mohsen Heidari Ali Ahmadfazeli Mehdi Vosughi Mehdi Fazlzadeh 《Korean Journal of Chemical Engineering》2018,35(4):1000-1008
This study considers the feasibility of uptake of cephalexin, an emerging contaminant, from aqueous solutions by using green local montmorillonite (GLM), montmorillonite coated with ZnO (ZnO/GLM) and montmorillonite coated with TiO2 (TiO2/GLM) in the presence of H2O2. Batch adsorption experiments were carried out as a function of pH, initial concentration of the cephalexin, adsorbent dosage, contact time, and temperature. Finally, the adsorbents were characterized by XRD, SEM and FTIR analyses. XRD patterns showed dramatic changes in the adsorbents after loading with the nanoparticles, confirming successful placing of the nanoparticles onto GLM. The GLM mineral surface after nanoparticle loading appears to be fully exposed and more porous with irregular shapes in particles diameters of 1-50 microns. FTIR analyses also confirmed dramatic changes in surface functional groups after modification with these nanoparticles. The results showed that the removal efficiency of cephalexin was better at lower pH values. Totally, the removal efficiency increased with increase in adsorbent dosage and contact time and decreased with concentration and temperature increase. The thermodynamics values of ΔG o and ΔH o revealed that the adsorption process was spontaneous and exothermic. In isotherm study, the maximum adsorption capacities (qm) were obtained to be 7.82, 17.09 and 49.26 mg/g for GLM, ZnO/GLM and TiO2/GLM, respectively. Temkin constant (B T ) showed that adsorption of cephalexin from solution was exothermic for all three adsorbents. 相似文献
15.
Synthesis of High‐Temperature‐Stable TiO2 and its Application on Ag+‐Activated Ceramic Tile
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Mevlut Gurbuz Burcak Atay Aydin Dogan 《International Journal of Applied Ceramic Technology》2015,12(2):426-436
The main purpose of study was to provide a common synergy using Ag+‐doped calcium phosphate powder and high‐temperature‐stable TiO2 for antibacterial and photocatalytic tile applications. Thermally stable SiO2‐modified TiO2 active layer was deposited on Ag+‐activated ceramic tiles by spray coating. The results showed that a nearly 100% cleanability degree was detected for SiO2‐modified TiO2 (TS)‐coated antibacterial tiles when compared uncoated and unmodified TiO2‐coated tiles. Antibacterial tests and colorimetric analyses indicated that ceramic tiles provide both antibacterial and photocatalytic properties simultaneously. 相似文献
16.
Ga-doped ZnO [GZO] thin films were employed for the transparent electrodes in dye-sensitized solar cells [DSSCs]. The electrical
property of the deposited GZO films was as good as that of commercially used fluorine-doped tin oxide [FTO]. In order to protect
the GZO and enhance the photovoltaic properties, a TiO2 blocking layer was deposited on the GZO surface. Then, TiO2 nanoparticles were coated on the blocking layer, and dye was attached for the fabrication of DSSCs. The fabricated DSSCs
with the GZO/TiO2 glasses showed an enhanced conversion efficiency of 4.02% compared to the devices with the normal GZO glasses (3.36%). Furthermore,
they showed better characteristics even than those using the FTO glasses, which can be attributed to the reduced charge recombination
and series resistance. 相似文献
17.
In order to improve the photocatalytic decomposition activity of benzene, which has been regarded as a typical volatile organic
compound in air, TiO2 catalysts modified with metals (Pt, Cu, and Fe) were prepared and tested. Certain correlations between the photocatalytic
activities and the optical properties of those catalysts were also found and discussed by using UV-visible spectroscopy and
a photoluminescence spectroscopy. Among the metal impregnated TiO2, the Pt impregnated TiO2 showed the best activity and it was even better than that of P-25 which is widely used in commercial applications. For the
various metal impregnated TiO2 samples, certain proportional relationships were found between the observed photoluminescence values and photocatalytic activities.
On the other hand, in UV-visible spectra for metal impregnated TiO2 samples, the transmittance value was reduced depending upon the loading of metals. It was thought that photocatalytic activity
increases from initial reaction state because the number of photoexcited electrons, which exist at Pt surface augment due
to the band gap energy change of Pt and TiO2 by sintering and light energy-absorbed electrons excited easily to conduction. In conclusion, it was confirmed that the enhanced
photocatalytic activity for high metal loading on TiO2 is related with the high concentration of excited electrons, which could be monitored through UV-visible spectra. 相似文献
18.
D. Zare-Hossein-abadi A. Ershad-Langroudi A. Rahimi S. Afsar 《Journal of Inorganic and Organometallic Polymers and Materials》2010,20(2):250-257
Transparent nanocrystalline TiO2 thin films with high photocatalytic activity and photo-induced wettability were successfully deposited on a glass slide.
Crystal phase transformations and particle size of TiO2 were investigated. Structural and morphological properties of the films were investigated. The photocatalytic activity of
the TiO2 films was evaluated. It is found that the photocatalytic activity of TiO2 thin films is significantly decreased by increasing the annealing temperature, which results in a decrease in BET surface
area and an increase in crystal size. In addition, increasing film thickness within a certain range significantly improves
the photocatalytic activity without causing crack formation of the TiO2 films. Photocatalytic oxidation and photo-induced wettability conversion on the films were investigated. It is found that
photo-induced hydrophilic conversion is observed even on the samples annealed at high temperature. The best photo-generated
activities are obtained by optimization of dip-coating cycles and annealing temperatures. 相似文献
19.
Zhixiong Zhou Lihua Zhu Jing Li Heqing Tang 《Journal of Applied Electrochemistry》2009,39(10):1745-1753
Uniform TiO2/SiO2 composite films were prepared on ITO substrates by electrodeposition, and highly photoelectrocatalytic (PEC) activity of
the composite films was observed toward the degradation of methyl orange (MO) in aqueous solutions. It was further found that
their PEC activity was dependent on the electrodeposition parameters including deposition time, solution pH and SiO2 content. Under the optimized condition, the PEC degradation of MO on TiO2/SiO2 composite film electrode could be enhanced about 14 times relative to that on neat TiO2 film electrode. The high PEC activity of the TiO2/SiO2 composite film electrode was mainly attributed to the enhancement of the charge separation of photo-generated electron-hole
pairs by the dispersion of SiO2 nanoparticles in the TiO2 matrix with the aid of the applied electric field. 相似文献
20.
Nanoparticles of SiO2 or TiO2 have been added in the preparation of heat-resisting concretes of two types. The major technical and chemical characteristics
have been determined. Features have been found in some of the technological operations in making the concretes of both types,
and also aspects of the physicomechanical properties. Higher chemical stability has been found for heat-resisting concrete
containing TiO2 nanoparticles in an NaOH solution. 相似文献