共查询到20条相似文献，搜索用时 640 毫秒
1.
In this study, supported nonmetal (boron) doping TiO2 coating photocatalysts were prepared by chemical vapor deposition (CVD) to enhance the activity under visible light irradiation and avoid the recovering of TiO2. Boron atoms were successfully doped into the lattice of TiO2 through CVD, as evidenced from XPS analysis. B-doped TiO2 coating catalysts showed drastic and strong absorption in the visible light range with a red shift in the band gap transition. This novel B-TiO2 coating photocatalyst showed higher photocatalytic activity in methyl orange degradation under visible light irradiation than that of the pure TiO2 photocatalyst. 相似文献
2.
The structural characteristics and optical and electrical properties of molecular-beam-epitaxy (MBE) grown ZnS0.8Se0.2 thin films on indium-tin-oxide(ITO) glas substrates were investigated in this work. TheX-ray diffraction (XRD) results indicated that high quality polycrystalline ZnS0.8Se0.2 thin film grown at the optimized temperature had a prefered orientation along the (111) planes. The transmission electron
microscopy (TEM) cross-sectional micrograph of the sample showed a well defined columnar structure with lateral crystal dimension
in the order of a few hundred angstroms. Ultraviolet (UV) photoresponsivity as high as 0.01 A/W had been demonstrated and
for wavelengths longer than 450 nm, the response was down from the peak response by more than 3 orders of magnitude. The thin
ZnS0.8Se0.2 photosensor layer, with a wide energy gap and anisotropic electrical property, makes a transmission UV liquid crystal light
valve (LCLV) with high resolution feasible.
Project supported by the National Natural Science Foundation of China (No. 59910161981) and RGC grant from the Hong Kong Government
Grant (No. NSFC/HKUST 35), China 相似文献
3.
A skutterudite-related antimonide, CoFe3Sb12, was prepared with vacuum melting. XRD analysis showed the material contained Sb, FeSb2, CoSb2 and CoSb3 phases. The electrochemical properties of the ball-milled CoFe3Sb12−10 wt% graphite composite were studied using pure lithium as the reference electrode. A maximal lithium inserting capacity
of about 860 mAh/g was obtained in the first cycle. The reversible capacity of the material was about 560 mAh/g in the first
cycle and decreased toca. 320 mAh/g and 250 mAh/g after 10 and 20 cycles respectively.Ex-situ XRD analyses showed that the antimonides in the pristine material were decomposed after the first discharge and that antimony
was the active element for lithium to insert into the host material.
Project supported by the National Natural Foundation of China (No. 59771032) and the RFDP of the Education Ministry of China
(No. 20010335045) 相似文献
4.
Discovery of ultrahigh-T spinel-garnet granulite with pure CO<Subscript>2</Subscript> fluid inclusions from the Altay orogenic belt,NW China 总被引：1，自引：0，他引：1
We first report discovery of the spinel-garnet-orthopyroxene granulite with pure CO2 fluid inclusions from the Fuyun region of the late Paleozoic Altay orogenic belt in Central Asia, NW China. The rock is characterized
by an assemblage of garnet, orthopyroxene spinel, cordierite, biotite, plagioclase and quartz. Symplectites of orthopyroxene
and spinel, and orthopyroxene and cordierite indicate decompression under UHT conditions. Mineral chemistry shows that the
orthopyroxenes have high XMg and Al2O3 contents (up to 9.23 wt%). Biotites are enriched in TiO2 and XMg and are stable under granulite facies conditions. The garnet and quartz from the rock carry monophase fluid inclusions which
show peak melting temperatures of around-56.7°C, indicating a pure CO2 species being presented during the ultrahigh-T metamorphism in the Altay orogenic belt. The inclusions homogenize into a
liquid phase at temperatures around 15.3–23.8°C translating into CO2 of the order of 0.86–0.88 g/cm3. Based on preliminary minerals paragenesis, reaction textures and petrogenetic grid considerations, we infer that the rock
was subjected to UHT conditions. The CO2-rich fluids were trapped during exhumation along a clockwise P-T path following isothermal decompression under UHT conditions.
Project supported by the National Basic Research Program (973) of China (No. 2001CB409801), the Exemplary Young Teacher Education
and Scientific Research Award Plan of China University, and Postdoctoral Fund of China (No. 2003033033), Postdoctoral Fund
of Zhejiang Province, and Starting Fund of Education Ministry, China 相似文献
5.
An efficient visible-light-responsive BiOBr/TiO2 heterojunction nanocomposite was fabricated successfully using in-situ depositing technique at room temperature by introducing BiOBr onto the surface of TiO2 nanobelts pre-prepared by hydrothermal reaction and etched with H2SO4. The obtained particles were characterized by XRD, SEM, TEM, XPS, UV-Vis DRS and PL techniques. BiOBr/TiO2 heterojunction nanocomposites with different mass ratios of m(BiOBr)/m(TiO2) were discussed in order to get the best photocatalytic activity, and BiOBr/TiO2-1.0 was proved to be the optimal mass ratio. BiOBr/TiO2-1.0 exhibited excellent photocatalytic activity in the degradation of RhB compared with TiO2 nanobelts, pure BiOBr and the mechanical mixture of TiO2 nanobelts and BiOBr. At last, a possible mechanism of photocatalytic enhancement was proposed. 相似文献
6.
Study of the SISO mixedH
2/l1 problem for discrete time systems showed that there exists a unique optimal solution which can be approximated within any
prescribed missing error bound inl
2 norm with solvable suboptimal solutions and solvable superoptimal solutions.
Project supported by the National Natural Science Foundation of China (No. 60174026) and the Scientific Research Foundation
for Returned Overseas Chinese Scholars of Zhejiang Province (No. J20020546) 相似文献
7.
A novel metallo-organic chemical vapor deposition (MOCVD) technique has been applied to the preparation of the photocatalytic
titanium dioxide supported on activated carbon. The effects of various condition parameters such as carrier gas flow rate,
source temperature and deposition temperature on the deposition rate were investigated. The maximum deposition rate of 8.2
mg/(g·h) was obtained under conditions of carrier gas flow rate of 400 ml/min, source temperature of 423 K and deposition
temperature of 913 K. The deposition rate followed Arrhenius behavior at temperature of 753 K to 913 K, corresponding to activation
energy E
a of 51.09 kJ/mol. TiO2 existed only in anatase phase when the deposition temperature was 773 K to 973 K. With increase of deposition temperature
from 1073 K to 1273 K, the rutile content sharply increased from 7% to 70%. It was found that a deposition temperature of
773 K and a higher source temperature of 448 K resulted in finely dispersed TiO2 particles, which were mainly in the range of 10–20 nm.
Project (No. 90206007) supported by the National Natural Science Foundation of China 相似文献
8.
α-diketones and β-diketones react with Grignard reagents in the presence of a catalytic amount of Cp2TiCl2 to yield α-ketols and corresponding ketones respectively. Sulfoxides can be deoxygenated by Cp2TiCl2/Al system. The possible mechanisms are also discussed.
Project (No. 20072033) supported by the National Natural Science Foundation of China and the Specialized Research Fund for
the Doctoral Program of Higher Education Ministry, China 相似文献
9.
以Ti（SO4）2为原料,采用氨水水解法制备氮掺杂二氧化钛前驱体,煅烧得到氮掺杂二氧化钛纳米粉体,作为功能活性组分．利用FT-IR红外光谱和激光粒度等方法对所制备的活性组分进行表征．将功能活性组分分散到水性乳胶涂料体系中,通过高速搅拌使其均匀分散,制得改性乳胶涂料．以30w日光灯管为光源,用甲醛降解反应考察了复合乳胶涂料的光催化活性．结果表明,复合了该活性组分的乳胶涂料具有优良的光催化净化空气的性能．N掺杂量对其光催化活性有较大的影响,当氮的掺杂量为0．7wt％,七天后光催化甲醛降解率达到最高92％． 相似文献
10.
This paper describes the preparation and properties of TiNx-SiO2 double-layered antireflective(AR) coatings that were applied with print process. The coating material was analyzed and TiNx was used instead of TiO2 as high refractive material. The influence of solution concentration on AR property was studied. The testing result shows that the coatings using print process are featured with excellent mechanical property and the AR property is comparable to American Southwall AR product. It is expected that the study would promote the industrialization progress in AR coatings. 相似文献
11.
TiO2 nanoparticles(NPs)were prepared via the hydrothermal route of TiO2 xerogel in nitric acid, hydrochloric acid and acetic acid. The physico-chemical properties of the powders were characterized by X-ray diffraction(XRD)and N2 adsorption desorption techniques. The effects of the different acids on the structure(crystal phase)and texture(primary particle size and porosity)of the TiO2 powders were explored. Results indicated that acetic acid facilitated the formation and stability of pure anatase phase. On the other hand, nitric acid and hydrochloric acid led to the transformation from anatase to rutile. The catalyst synthesized via the hydrothermal route of TiO2 xerogel in the low concentration hydrochloric acid solution(Ti-HCl-0.15)had the highest photocatalytic activity than the catalysts obtained in the other two acid solutions. The effects of the different acids were discussed in terms of acid strength, chelating effect and the thermal stability of the adsorbed acidic anions. 相似文献
12.
MBE growth of ZnSxSe1−x thin films on ITO coated glass substrates were carried out using ZnS and Se sources with the substrate temperature ranging
from 270°C to 330°C. The XRD σ/2σ spectra resulted from these films indicated that the as-grown polycrystalline ZnSxSe1−x thin films had a preferred orientation along the (111) planes. The evaluated crystal sizes as deduced from the FWHM of the
XRD layer peaks showed strong growth temperature dependence, with the optimized temperature being about 290 °C. Both AFM and
TEM measurements of these thin films also indicated a similar growth temperature dependence. High quality ZnSxSe1−x thin film grown at the optimized temperature had the smoothest surface with lowest RMS value of 1.2 nm and TEM cross-sectional
micrograph showing a well defined columnar structure.
Project supported by the National Science Council of PRC (No. 59910161981) and RGC grant from the Hong Kong Government under
Grant (No. NS-FC/HKUST 35) 相似文献
13.
A Pr-doped TiO2-NTs/SnO2-Sb electrode was prepared by a simple method, cyclic voltammetry(CV). The methyl orange(MO)aqueous solution was selected as a simulated wastewater. The ordered microstructural TiO2-NTs substrate was synthesized by an electrochemical method to obtain large specific surface area and high space utilization. The phase structure, electrode surface morphology and electrochemical properties of electrodes were characterized by XRD, SEM and electrochemical technology, respectively. The results showed that praseodymium oxide was successfully doped into the SnO2-Sb film by CV method. Due to the doped Pr, the oxygen evolution potential increased from 2.25 V to 2.40 V. The degradation of MO was investigated by UV-vis. The C t /C 0 (φ) was studied as a function to obtain the optimal parameters, such as the amount of doped Pr, current density and initial dye concentration. In addition, the degradation process followed pseudo-first-order reaction kinetics and the rate constant was 0.099 3 min-1. The result indicated that the introduction of Pr reduced the formation of oxygen vacancies or enhanced the formation of adsorbed hydroxyl radical groups on the surface, thus leading to better activity and stability. 相似文献
14.
The crystal form of TiO2 is a crucial focus of research on the photocatalytic degradation of gaseous pollutants by TiO2-based composite photocatalysts. To explore the synergistic effect of mixed crystalline TiO2 on gaseous organic-pollutant photocatalytic degradation, we synthesized a series of TiO2 nanoparticles with controllable phase ratios. We explored the role of the TiO2 phase ratio on the photocatalytic activity and degradation pathway in the photodegradation of 2-propanol (IPA). We estimated the crystallite size and crystal proportions of anatase and rutile by X-ray diffraction. We used the Brunauer–Emmett–Teller method to calculate the specific surface area and Fourier transform infrared spectroscopy to characterize the surface chemistry of the samples. Our results show the photocatalytic activities of pure anatase and the sample with 8.6% rutile to be much better than those of the samples with a phase junction and pure rutile. As such, anatase is the better option for the study of photodegradation design and preparation of gas-phase organic pollutants. 相似文献
15.
Thermodynamic Optimization of DyCl3 -NaCl System 总被引：2，自引：0，他引：2
In this paper, the phase diagram of the DyCl3 -NaCl system is optimized and calculated with CALPHAD ( calculation of phase diagram ) technology. A set of thermodynamic functions of compounds Na3 DyCl6, NaDyCl4, and NaDY2 Cl7 have been optimized and calculated based on an interactive computer-assisted analysis. The optimized thermodynamic parameters, calculated phase diagram and experimental phase diagram are thermodynamically serf-consistent. 相似文献
16.
The chemisorption properties of N18O adsorption on TiO2(110) surface were investigated by experimental and theoretical methods. The results of temperature programmed desorption
(TPD) indicated that the temperatures of the three desorption peaks of the main N2 molecules were at (low) temperature of 230 K, 450 K and (high) temperature of 980 K. This meant that N18O decomposed and recombined during the process of N2 desorption after N18O was exposed. Analysis of the stable combination and orbital theory calculation of the surface reaction of NO adsorption
on the TiO2(110) cluster model showed that there was clear preference for the Ti-NO orientation. 相似文献
17.
Well-cubic perovskite lanthanum aluminate (LaAlO3) film on (110) silicon substrate was fabricated by sol-gel method with corresponding inorganic salts. Lanthanum acetate and
aluminum acetate glacial acetic acid solutions were prepared via ligand exchange starting from lanthanum nitrate hexahydrate
and aluminum nitrate hexahydrate after being refluxed. (CH3CO)2O removed nitrates and the crystallized H2O completely, acetylacetone (AcAc) was partially bidentated with metallic ion of the metallic acetates and formed La(OAc)3−x
(AcAc)
x
which were hydrolyzed into La(AcAc)3−x(OH)
x
by adding 10 ml 0.4% methyl cellulose (MCL) solution. The La(AcAc)3−x
(OH)
x
, polymerizing and combining with MCL, formed the LaAlO3 sol precursor with heteropolymeric structure and formed film easily. The epitaxial LaAlO3 film on Si(110) substrate was crystallized after being annealed in thermal annealing furnace for 650–750 °C/30 min. The morphologies
and microstructures were characterized. The refractive index of the LAO film was 1.942 to 2.007; the dielectric constant and
the dissipation factors were estimated to be 23–26 and 2.1×10−4−2.4×10−4 respectively.
Project (No. 2002CB613305) supported by the National Basic Research Program (973) of China 相似文献
18.
A part of the heavy metals in estuary and coastal zone occurs naturally in the environment; the other part is due to human activity; so the directly measured concentration of heavy metal does not automatically indicate anthropogenic enrichment. Fe2O3 was used in this study as conservative tracer to distinguish natural components from anthropogenic components of heavy metal sediment concentration in the Zhujiang estuary. Compared with clay and Al2O3, Fe2O3 is more suitable as reference element. The final results showed that two zones in the Zhujiang estuary were seriously contaminated by heavy metals. One nearby the Humen mouth; the other around the west coast of the estuary. The horizontal distribution of heavy metals indicates that Zn, Ni and Cu have wider contaminating areas than TiO2, V and Cr in the estuary. 相似文献
19.
以铁尾矿砂为原料,用NaOH,HNO3调节pH值,采用熔融-水热两步法制备了铁尾矿砂光催化剂。利用X射线衍射仪、紫外/可见/近红外光谱仪等对铁尾矿砂光催化剂的结构性能进行表征;以罗丹明B溶液为标准降解物,汞灯为光源,探讨在不同pH条件下合成的铁尾矿砂光催化剂的光催化活性。结果表明,铁尾矿砂光催化剂的主要成分为Fe2.35Si0.65O4和NaNO3,且具有良好的光催化效果;在pH 8.5条件下制备的样品具有多孔结构,光催化性能最强;光照120 min时此样品可降解95.1%的罗丹明B溶液;·O2-是光催化反应过程中最主要的氧化活性自由基。 相似文献
20.
This paper proposes a new approach for multi-objective robust control. The approach extends the standard generalizedl
2 (Gl
2) and generalizedH
2 (GH
2) conditions to a set of new linear matrix inequality (LMI) constraints based on a new stability condition. A technique for
variable parameterization is introduced to the multi-objective control problem to preserve the linearity of the synthesis
variables. Consequently, the multi-channel multi-objective mixed Gl
2/GH
2 control problem can be solved less conservatively using computationally tractable algorithms developed in the paper.
Project supported by the National Natural Science Foundation of China (No. 60374028), and the Scientific Research Foundation
for Returned Overseas Chinese Scholars, Ministry of Education (No. [2004]176) 相似文献