共查询到20条相似文献,搜索用时 46 毫秒
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通过溶胶-凝胶(Sol-Gel)法制备了铁、镧共掺杂纳米TiO2,采用X线衍射仪(XRD)、X线光电子能谱(XPS)、紫外-可见分光光度计(UV-Vis)和荧光分光光度计(FL)等测试手段对样品进行表征。结果表明,500℃煅烧后的掺杂TiO2均呈锐钛矿型,平均粒径为6.1nm,掺杂抑制了TiO2粒径的长大,掺杂的Fe3+、La3+能有效进入TiO2晶格。掺杂使TiO2的吸收带边红移且在可见光区的光吸收增强,样品的荧光强度越小,催化效果越好。可见光光催化降解甲基橙实验结果表明,可见光照射5h,最佳共掺杂的0.01%Fe/0.6%La-TiO2对甲基橙的降解率达40.7%。 相似文献
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The effect of annealing on vertically aligned TiO2 NWs deposited by glancing angle deposition (GLAD) method on Si substrate using pressed and sintered TiO2 pellets as source material is studied.The FE-SEM images reveal the retention of vertically aligned NWs on Si substrate after annealing process.The EDS analysis of TiO2 NWs sample annealed at 600℃ in air for 1 h shows the higher weight percentage ratio of~2.6(i.e.,72.27% oxygen and 27.73% titanium).The XRD pattern reveals that the polycrystalline nature of anatase TiO2 dominates the annealed NWs sample.The electrical characteristics of Al/TiO2-NWs/TiO2-TF/p-Si (NW device) and Al/TiO2-TF/p-Si (TF device) based on annealed samples are compared.It is riveting to observe a lower leakage current of~1.32×10-7 A/cm2 at+1 V with interface trap density of~6.71×1011 eV-1cm-2 in NW device compared to~2.23×10-7 A/cm2 in TF device.The dominant leakage mechanism is investigated to be generally Schottky emission;however Poole-Frenkel emission also takes place during high reverse bias beyond 4 V for NWs and 3 V for TF device. 相似文献
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Bi_2O_3/TiO_2纳米复合物的微波合成及光催化性质 总被引:4,自引:2,他引:2
以硝酸铋和硫酸钛为原料,通过直接投料微波辐射水解合成法制备了掺铋TiO2纳米复合物,并用XRD、TEM进行了表征。结果表明,直接投料摩尔比为1∶10掺铋TiO2纳米复合物,经500℃热处理后晶型为锐钛矿型,粒径为6~10nm。以催化降解甲基橙来考察其光催化活性,结果表明所制备的纳米复合物是一个好的催化剂。研究了Bi3+的掺杂量、热处理温度、催化剂用量对掺铋TiO2纳米复合物光催化性能的影响。当催化剂用量为1g/L时,2mg/L的甲基橙溶液在紫外光辐射30min后,降解率达到97%。该复合物对甲基橙溶液的光催化降解符合一级动力学方程。 相似文献
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锑掺杂二氧化钛的制备及其可见光催化性能 总被引:1,自引:1,他引:0
用草酸氧钛酸分解法制备了锑掺杂的二氧化钛光催化剂粉体。用XRD和TEM测定了样品的晶型、粒度等表征参数。结果表明:所制备的掺杂TiO2光催化剂为金红石型TiO2和锐钛矿型TiO2的混晶,颗粒直径在100nm左右。在可见光下,用锑掺杂量为0.2%(摩尔分数)、900℃煅烧保温0.5h后的TiO2降解6h后,甲胺磷的无机磷回收率达到96.4%。 相似文献
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Fe3+掺杂TiO2纳米晶溶胶的制备及性能 总被引:1,自引:0,他引:1
采用sol-gel法制备了Fe3+掺杂锐钛矿型TiO2纳米晶溶胶。对溶胶的物相结构和粒度分布进行了分析,并考察了薄膜的UV-Vis吸收光谱及溶胶的光催化性能。结果表明:Fe3+掺杂可提供杂质能级抑制电子与空穴的复合,且对TiO2溶胶粒子具有细化作用,因此TiO2溶胶的光催化活性提高,比未掺杂时最大提高了近30%。但Fe3+掺杂过多可能成为电子与空穴复合的中心,导致TiO2溶胶的光催化活性降低。r(Fe:Ti)的最佳范围为0.25~0.50。 相似文献
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通过掺杂 ( Pb1-x Srx) Ti O3( PST)系铁电陶瓷的制备 ,初步研究了掺杂、烧结温度、测试频率等对 PST系陶瓷材料介电性能的影响。在相同的 Pb/ Sr配比下 ,La2 O3掺杂较同样份量的 Mn O2掺杂所制得的样片的温度系数要高 ,介电损耗要小 ,而适当高的烧结温度有利于其介电性能的改善。随着测试频率的增加 ,测得的材料介电常数略有下降 ,而居里温度与温度系数基本维持不变。 相似文献
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The present investigation describes that the iron (Fe) doped ZnSe hexagonal nanorods were successfully synthesized via chemical synthesis specifically galvanostatic mode of electrodeposition and addition of Fe in order to improve the PEC performance of ZnSe electrodes using a galvanostatic mode. These crystalline Fe doped ZnSe hexagonal nanorods electrodes are characterized by X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), and optical properties, such as UV–vis spectroscopy, photoluminescence spectroscopy, electrochemical impedance spectroscopy (EIS), Raman spectroscopy and photoelectrochemical properties. It is seen that at 5% Fe doped ZnSe hexagonal nanorods show the open circuit voltage (Voc) was 100 mV, and short circuit current (Isc) was 110 μA. The observed fill factor and efficiency were found to be 44% and 0.15%, respectively. 相似文献
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Gopal Sapkota Karol Gryczynski Roy Mcdougald Arup Neogi U. Philipose 《Journal of Electronic Materials》2012,41(8):2155-2161
We report on the synthesis Zn1?x Fe x O nanotubes with average tube diameter of 60?nm to 100?nm and wall thickness of about 20?nm. The nanotubes were synthesized by a low-temperature electrochemical process, and their morphology was found to be sensitive to the electrolyte concentration and growth time. The maximum Fe doping achieved by this process was estimated to be approximately 4?wt.%. High-resolution transmission electron microscopy and x-ray diffraction showed good crystalline quality of the doped and undoped nanotubes with preferential growth along the wurtzite c-axis. The Fe-doped nanotubes exhibit wurtzite crystal structure with an increase in the c-axis lattice constant when compared with the undoped nanotubes, indicative of the fact that Fe ions substitute for Zn as 2+ ions in the ZnO crystal lattice. Further evidence of Fe as a substitutional dopant is provided by Raman and photoluminescence spectroscopy. A comparison of the effective magnetic moment in the undoped and doped nanotubes reveals the presence of four unpaired electrons in the Fe-doped sample and zero unpaired electrons for the undoped sample. 相似文献
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In this study, vanadium oxide (V2O5) was doped with different percentages of fluorine (F) and deposited on glass substrates by using spray pyrolysis method. The substrate temperature during the film deposition was kept constant at 450 °C. The obtained nanostructured thin films were characterised by X-ray Diffraction (XRD), UV–visible spectroscopy, and Scanning Electron Microscopy (SEM). The XRD results showed that F doped films are polycrystalline with main phase of β-V2O5 and with preferred orientation along (200). Increasing dopant to 30% improved crystallinity, but for more doping, the structure of samples tended to be amorphous. VF2 phase was also observed when doping of F was increased to more than 10%. The incorporation of fluorine in nano-layers led to a decrease in optical absorption by 1.3 a.u. and an increase in band gap of energy from 2.23 to 2.83 eV. SEM images showed that the shape of grains was spherical with 10% doping and changed to bacilliform with 70% F concentration. The cyclic voltammetry results obtained for different samples showed expanded anodic and cathodic peaks for the undoped sample. The samples prepared with 20% and 40% F-doping level had milder anodic and cathodic peaks. However, by increasing the dopant to 70%, the peaks were expanded. The thin film with 40% F-doping showed the least resistance, but the resistance increased dramatically with 70% F dopant concentrations. 相似文献
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掺钛和锆改性的钙硼硅系微晶玻璃之性能 总被引:1,自引:0,他引:1
以TiO2、ZrO2为改性剂,制备CaO-B2O3-SiO2系微晶玻璃。对其烧结和介电性能进行了研究,并采用XRD,SEM对微观结构进行了探讨。结果表明:添加适量的TiO2或是混合添加TiO2、ZrO2均能改善CaBSi系微晶玻璃的性能。混合添加比单一添加TiO2更有效。结合材料的烧结性能、介电性能和微观结构,以840℃烧成的添加w(TiO2)为2%、w(ZrO2)为2%的试样性能最佳,其εr为7.1、tanδ为3×10–3,在20~400℃之间的热膨胀系数为7.8×10–6℃–1。 相似文献
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In this study, sol–gel spin coating route was carried out to prepare Scandium doped ZnO thin films with different controlled percentage (1–7%). Particularly, it has been demonstrated, through original conjoint morphological-structural and optical investigations, that some interesting physical properties were induced. Indeed, X-ray diffraction (XRD) analysis shows that (002) preferential crystalline plane for Sc doped ZnO films was kept along with ZnO hexagonal würtzite structure, although Sc doping seemed to cause a decrease in crystallinity. Except for 1 at% Sc doping ratio, optical band gap changes reversely with Urbach energy with a decrease in optical gap and a broadening of the absorption tail. Ab-initio calculations of lattice dynamical properties outlined additional strong hybridization between Sc and O atoms and show the stability of Scandium doped ZnO. 相似文献
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A novel, facile and cost-effective single step aqueous sol–gel method for the synthesis of anatase TiO2 nanorods without the assistance of structure-directing organic/inorganic templates is reported. We specifically demonstrate a pseudo-inorganic templating method using ammonium iron (III) sulfate. Highly thermal stable anatase TiO2 nanorods were obtained using titanium oxysulfate and ammonium iron (III) sulfate as precursors. The structural, microstructural and chemical analyses of the nanorods synthesized, strongly supported the pseudo inorganic templating role of ammonium iron (III) sulfate on the formation of nanorod morphology. The materials have been characterized using different techniques such as TEM, XRD, BET surface area measurement, diffuse reflectance spectra and XPS. TEM study confirmed the rod shape of nano-anatase TiO2, having a diameter in the range of 20–40 nm and a length of 100 nm. XPS investigation showed that along with Fe3+, nitrogen and sulfur were also been doped into the TiO2 lattice from the single source dopant precursor ammonium iron (III) sulfate. Moreover, UV/vis diffuse reflectance spectra of nanorods showed red-shifts towards visible light and a corresponding decrease in band-gap energies consistent with an n-type doping of the anatase TiO2 matrix. This aqueous sol–gel synthesis of anatase nanorod with pseudo inorganic templating explores the advantages of inexpensive precursors, control over the powder morphology and optical properties, and distribution of the dopants over TiO2 at nano level due to homogeneous mixing of the precursors. Finally the photocatalytic analysis showed that the TiO2 nanorod have two times higher activity than the commercially available Degussa P 25. 相似文献
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A photoactive compound extracted from a fungus (Hypocrella bambuase), named hypocrellins, was used as template to synthesize thermally stable mesoporous materials. The synthesized mesoporous titania samples were characterized using a combination of various physicochemical techniques, such as N2 adsorption/desorption measurement, X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), UV–vis diffuse reflectance spectroscopy (DRS) and Fourier transform infrared spectroscopy (FT-IR). The results of physicochemical characterizations showed that the as-synthesized sample was a composite of highly crystalline mesoporous anatase titania and graphitic carbon (gc–MTiO2), which implies the dual function of hypocrellins as template and “dopant”. The in situ doped graphitic carbon significantly increased the visible-light absorbance of TiO2. The gc–MTiO2 exhibited efficient photocatalytic activity under visible-light for photodegradation of acetaldehyde, a common indoor air pollutant. The photophysics and electron dynamics in this photocatalytic process were studied by time-resolved FT-IR spectra, in particular on the nano- to milli-second time scale. It is observed that electrons were injected into the conduction band of gc–MTiO2 and they were decayed to deep traps caused by graphitic carbon. The reported strategies could open up new uses for mesoporous titania self-doped with carbon in applications such as solar cells, photocatalysts, photoelectrical devices, and photo-induced sensors. 相似文献
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采用溶胶-凝胶结合氢气还原方法,制备了Fe与TiO2两相共存的纳米复合物。透射电子显微镜(TEM)图片显示,纳米复合物的颗粒大小为100~300nm,且具有明显的核/壳结构。X射线衍射结果表明,纳米复合物中存在a-Fe与金红石型TiO2结构,未发现其他杂相。振动样品磁强计(VSM)的测量结果表明,样品具有较高的比饱和磁化强度。研究表明,通过控制前驱物的用量,能有效改变样品的磁性。热重分析(TGA)结果表明,样品具备很好的抗氧化性。复合介电谱和磁谱表明,在测量的微波频率范围内,样品的介电损耗大于磁损耗。 相似文献