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1.
用溶胶-凝胶法制备了在可见光照射下具有光催化活性的掺杂P(t Ⅳ)离子的非晶态微孔TiO2,表面积为160~200 m2/g;含3.0%Pt(Ⅳ)的AMM-Ti具有最大的光催化活性. X射线精细结构分析(EXAFS)表明,单个的PtCl4分子均匀地分布在非晶态二氧化钛表面;用这种光催化剂降解2,4-二氯苯氧基乙酸时,2,4-二氯苯酚是主要的中间物,通过Langmuir-Hinshelwood 方程的线性形式估算了反应速率常数k 和吸附平衡常数K,研究了光催化起始反应速率和反应物起始浓度之间的关系,同时,提  相似文献   

2.
O6432006032784可见光激发下PtⅣClx/Ti O2的光诱导电子转移研究=Study on electrontransfer on PtⅣClx/Ti O2induced byirra-diation of visible light[刊,中]/陈亦琳(福州大学光催化研究所.福建,福州(350002)),李旦振…∥高等学校化学学报.—2006,27(2).—340-342利用表面光电压谱(SPS)和电场诱导表面光电压谱(EFISPS)对PtⅣClx/Ti O2进行了表面光伏特性的研究,揭示了催化剂光生载流子跃迁行为与其表面光伏特性之间的联系,这对于全面认识PtⅣClx/Ti O2可见光降解有机物的反应机理具有重大意义。图5参5(于晓光)O644.120060327…  相似文献   

3.
Ti(SO4)2水热法制纳米SO2-4/TiO2光催化剂的光谱研究   总被引:7,自引:0,他引:7  
以Ti(SO4) 2 水溶液为前驱物 ,尿素为沉淀剂 ,采用水热沉淀 加热分解 浸渍烧结法制备纳米SO2 -4/TiO2 固体超强酸光催化剂 ,并用XRD ,BET ,FTIR ,DRS和FS等对中间态粒子和产物进行表征 ,以光催化降解罗丹明B为模型反应 ,筛选制备SO2 -4/TiO2 光催化剂的优化条件。结果表明 ,用Ti(SO4) 2 为前驱物 ,水热法能在较低的温度、弱碱性介质中 ,得到纳米锐钛矿型TiO2 晶体 ;在 30 0℃下控制焙烧 4h ,基本能使水热反应副产物 (NH4) 2 SO4等分解 ,又避免H2 SO4大量的流失 ;SO2 -4负载量和烧结时间是影响SO2 -4/TiO2 光催化活性的主要因素 ,当SO2 -4负载量 11%、烧结温度 4 5 0℃时 ,制备的SO2 -4/TiO2 光催化剂活性较高 ,达P 2 5光催化剂的水平  相似文献   

4.
采用溶胶-凝胶法制备了金红石型TiO_2/ZnTiO_3复合光催化剂,对其进行650℃保温1 h的热处理;通过X射线衍射(XRD)、扫描电子显微镜(SEM)、X射线光电子能谱(XPS)、荧光光谱(PL)对样品进行表征,并以亚甲基蓝(MB)溶液为目标污染物,研究了样品的光催化性能。结果表明,TiO_2为金红石结构,随着Zn/Ti量比增加,TiO_2晶粒尺寸减小;当Zn/Ti的量比达到2%时,有新相ZnTiO_3生成。TiO_2/ZnTiO_3(Zn/Ti=8%)展现出最高的光催化活性,这归因于表面羟基含量增加以及形成的TiO_2/ZnTiO_3半导体复合结构加快了光生电子与空穴的转移。反应进行90 min后,对MB的降解率达到68.3%,反应速率常数k为0.012 min~(-1),分别为纯TiO_2的1.85倍和3倍。  相似文献   

5.
RuO2/TiO2复合光催化剂的制备及性能研究   总被引:4,自引:0,他引:4  
采用溶胶-凝胶-浸渍法制备了RuO2/TiO2复合光催化剂, 以紫外灯为光源, 直接耐晒黑G溶液的光催化降解为模型反应, 研究了RuO2/TiO2的光催化性能. 结果表明 掺杂量ω(RuO2)为0.16%、煅烧温度500 ℃、催化剂投加量为5.00 g·L-1时, RuO2/TiO2复合光催化剂催化活性最高. 直接耐晒黑G降解反应遵从Langmuir-Hinshelwood动力学模型, 测得反应速率常数为4.94×10-3 mmol(L·min)-1和吸附常数14.2 L·mmol-1.  相似文献   

6.
杨悦  赵翠真  于晨光  黄枭  吕威 《发光学报》2014,(12):1449-1454
制备了3种不同形貌的Ti O2结构:纳米杯、(001)纳米片、(100)纳米片,并进一步与Pt纳米粒子复合以去除污水中的有机染料。透射电镜结果证实了3种Ti O2纳米结构的形成,观察到了附着其上的Pt纳米粒子。使用XRD确定了3种Ti O2纳米结构均为锐钛矿相。以罗丹明B作为有机染料,检测了不同形貌Ti O2及其Pt复合物的光催化性能。结果表明:纳米杯状的Pt/Ti O2在罗丹明B溶液中表现出最高降解率,在1.5 h内降解率可达99.1%。同时讨论了Ti O2及其复合物的光降解机理。  相似文献   

7.
CdS/TiO2/漂珠复合光催化剂制备及其降解高效氯氰菊酯研究   总被引:2,自引:0,他引:2  
采用溶胶-凝胶-浸渍法制备了Cds/TiO2/漂珠复合光催化剂,通过SEM,XRD对其结构进行了表征.以高效氯氰菊酯(BEC)杀虫剂的光催化降解为模型反应,研究了CdS/TiO2/漂珠的光催化性能,探讨了影响催化剂活性的因素及采用太阳光作光源处理BEC的可行性.结果表明,CdS/TiO2/漂珠投加量为3 000mg·L-1,初始浓度为45 mg·L-1、初始pH为6.5,通气量为200 mL·min-1时间为60 min,BEC降解率分别为92.1%(125W高压汞灯)和79.3%(5 W紫外灯),采用太阳光照射300 min,BEC降解率可达93.4%.BEC的降解反应遵从L-H动力学模型,测得反应速率常数9.80 mg·(L·min)-1,吸附常数4.36×10-3 L·mg-1.  相似文献   

8.
镶嵌Pt的二氧化钛纳米管的合成及其光催化性能研究   总被引:1,自引:0,他引:1  
以金红石相二氧化钛(TiO2)粉体为原料,采用水热法合成了二氧化钛纳米管(Titania nanotubes,简写为TNTs),然后把H2PtCl6的无水乙醇溶液引入到TNTs中,得到镶嵌Pt的二氧化钛纳米管(Pt/TNTs).利用透射电镜(TEM)、X射线衍射(XRI))和紫外-可见光谱(UV-Vis)对产物进行了表征,并重点研究了Pt/TNTs的光催化性能.结果表明,有直径约为3 nm的Pt纳米粒子插入到了TNTs中,且Pt粒子以Pt单质的形式存在.Pt/TNTs在可见光区域表现出较强的吸收,并且其起始吸收带边发牛明显红移.紫外光催化降解甲基橙实验结果表明,金红石相TiO2,TNTs和Pt/TNTs对甲基橙溶液的降解率分别达到46.8%,57.2%和84.6%,Pt/TNTs的光催化活性较金红石相二氧化钛粉体和纯TNTs有显著的提高.  相似文献   

9.
研究了以自制掺铁的锐钛矿型TiO2(即A-TiO2)光催化降解对硝基苯酚的动力学过程。结果表明:在可见光照射下,对硝基苯酚溶液为20mg·L-1、溶液调节为酸性(pH=2)、自制的掺铁0.1%(摩尔分数)A-TiO2的投入量1.0g·L-1、室温下搅拌下反应200min的条件下,对硝基苯酚的光催化降解的表观反应速率常数k(0.0050min-1)和降解率(64.52%)最大,拟合可见光下铁掺杂TiO2降解对硝基苯酚为一级反应。  相似文献   

10.
用Ti片和H2O2在较低的温度下通过控制反应时间制备了不同形貌的纳米TiO2.在80℃下反应10 min得到了和Ti片黏附较好的多孔纳米结构,延长反应时间先后得到了类花状和类棒状纳米结构.在80℃下反应4 h得到的纳米结构样品为非晶态,而反应10 h制备出以锐钛矿相为主的结晶态纳米结构.通过300℃退火得到的几乎是纯锐钛矿相的纳米TiO2.用紫外光照射降解RhB溶液的方法研究了纳米TiO2的光催化性能.结果表明7 cm2的退火后的类花状纳米TiO2降解染料分子的光催化效率是仅用紫外光降解的29.8倍.  相似文献   

11.
Two-dimensional scanning of a 0.6328 mum guided-light beam has been realized using noncolinear acousto-optic (AO) coplanar Bragg diffraction together with colinear AO guided-mode to substrate radiation-mode conversion in a Z-cut Xpropagation LiNbO3 proton-exchanged (PE) waveguide. The two surface acoustic (SAW) waves utilized are at the center frequencies of 500 and 200 MHz, propagating in the Y and X axes, respectively. Two-dimensional scanning of approximately 720 resolvable light beam spots, namely, 18 40 (horizontal vertical) scanning, has been demonstrated using a light beam of 1.0 mm aperture. The total number of resolvable beam spots can be greatly increased from 720 by simply utilizing SAW transducers of larger bandwidth and a light beam of greater aperture. It should also be possible to significantly increase the diffraction efficiency from 3 % by optimizing the parameters of the PE waveguide and the SAWs.  相似文献   

12.
A simple technique of pulse compression, based on the linear chirp compensation of self-phase modulation (SPM) spectra in dispersion shifted fibers, is demonstrated. The optimization procedure is carried out, for a short span of a single-mode fiber, using a parabolic law, which describes the behavior of the squared output pulse width versus the pump peak power in the case of Gaussian pulses. The experimental results give a minimum pulse duration of 233 fs, which is in good agreement with the model. Shorter and coherent pulses, down to 90 fs, have been obtained by inserting an interference filter at the optical output.  相似文献   

13.
Results of a study of the effect of γ-radiation on the spectral luminescence properties of cadmium tungstate crystals doped with silver, bismuth, and molybdenum cations are presented. Spectral characteristics of the nondnnnoped crystals are briefly described. Absorption and photo and X-ray luminescence spectra of the crystals taken before and after exposure to γ-radiation (5.5·104 Gy) are compared. It is found that the spectral characteristics of the crystals doped with silver, bismuth, and molybdenum cations do not change markedly after the exposure. The relation between the type of impurity-induced defects, individual characteristics of the impurity cations, and the character of the effect of γ-radiation on the spectral luminescence properties of impure crystals is analyzed (preliminarily). Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 64, No. 1, pp. 55–60, January–February, 1997.  相似文献   

14.
The Shanghai Synchrotron Radiation Facility(SSRF)booster ring,a full energy injector for the storage ring,is deigned to accelerate the electron beam energy from 150MeV to 3.5GeV that demands high extraction efficiency at the extraction energy with low beam loss rate when electrons are ramping.Closed orbit distortion(COD)caused by bending magnet field uniformity errors which affects the machine performance harmfully could be effectively reduced by bending magnet location sorting.Considering the affections of random errors in measurement,both ideal sorting and realistic sorting are studied based on measured bending magnet field uniformity errors and one reasonable combination of bending magnets which can reduce the horizontal COD by a factor of 5is given as the final installation sequence of the booster bending magnets in this paper.  相似文献   

15.
A review of schemes for multiple access in fiber optic networks shows that a hybrid of wavelength and code division multiple access (WCDMA) combines the best features of both. In particular, the hybrid scheme retains the large information carrying capacity of wavelength division multiple access (WDMA) and flexibility of code division multiple access (CDMA). In this paper WDMA, optical CDMA (OCDMA), and WCDMA networks are discussed. In OCDMA networks, concept of incoherent and coherent coding including inverse decoding and matched filter is introduced. The delay performance of both WDMA and WCDMA networks, under the simple suboptimum access protocols based on cyclic search, is computed. It has been shown quantitatively that tuning delay significantly affects the delay performance of both WDMA and WCDMA networks. Futhermore, delay performance of WCDMA networks is always better than the WDMA networks for the same tuning delay, load, and number of users.  相似文献   

16.
17.
Resonance scattering of elastic spherical shell and cylindrical shell while the surrounding fluid medium has absorption is studied. The normal mode solution derived using exact elastic theory and the separation of variables is still applicable. However, the scattering form function has to be modified for the absorbing medium, otherwise the unreasonable result would be obtained. The backscattering form function in the absorbing medium is redefined, and the form function of elastic spherical and cylindrical shell with vacuum or solid matter filled is calculated in various absorption conditions. The results show that the absorption of surrounding fluid leads to notable attenuation of the coincidence resonances in the mid-frequency, but it has a little influence on the low-frequency resonance scattering induced by the filler inside the shell.  相似文献   

18.
A versatile and low-cost single-beam self-referenced phase-sensitive surface plasmon resonance(SPR)sensing system with ultra-high resolution performance is presented.The system exhibits a root-mean-square phase fluctuation of ±0.0028.over a period of 45 min.i.e.a resolution of±5.2×10-9 refractive index units.The enhanced performance has been achieved through the incorporation of three design elements:a true single-beam configuration enabling complete self-referencing so that only the phase change associated with SPR gets detected,a differential measurement scheme to eliminate spurious signals not related to the sensor response,and the elimination of retardation drifts by incorporating temperature stabilization in the liquid crystal phase modulato .Our design should bring the detection sensitivity of non-labeling SPR biosensing closer to that achievable by conventional fluorescence-based techniques.  相似文献   

19.
Ta2O5 films are prepared on BK7 substrates with conventional electron beam evaporation deposition.The effects of SiO2 protective layers and annealing on the laser-induced damage threshold (LIDT) of the films are investigated.The results show that SiO2 protective layers exert little influence on the electric field intensity(EFI)distribution,microstructure and microdefect density but increase the absorption slightly.Annealing iS effective on decreasing the microdefect density and the absorption of the films.Both SiO2 protective layers and annealing are beneficial to the damage resistance of the films and the latter is more effective to improve the LIDT.Moreover,the maximal LIDT of Ta2O5 films is achieved by the combination of SiO2 protective layers and annealing.  相似文献   

20.
Gray cross correlation matching technique is adopted to extract candidate matches with gray cross correla- tion coefficients less than some certain range of maximal correlation coefficient called multi-peak candidate matches. Multi-peak candidates are extracted corresponding to three closest feature points at first. The corresponding multi-peak candidate matches are used to construct the model polygon. Correspondence is determined based on the local geometric relations between the three feature points and the multi-peak candidates. The disparity test and the global consistency checkout are applied to eliminate the remaining ambiguous matches that are not removed by the local geometric relational test. Experimental results show that the proposed algorithm is feasible and accurate.  相似文献   

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