首页 | 官方网站   微博 | 高级检索  
相似文献
 共查询到18条相似文献,搜索用时 109 毫秒
1.
Co nanowire arrays were prepared by anodic alumina oxide template,which formed during DC superposed pulse source anodization process. The structure of porous alumina template and properties of optical polarization of Co nanowire arrays are studied with the help of the scanning electron microscope, X-ray diffraction and infrared spectroscopy. The results showed that Co nanowire arrays have an excellent polarization property in near infrared region in 2700nm. We also found that the properties of optical polarization can also be controlled by adulterating kinds of electrodepositing metal and its alloys, by controlling length of nanowire, and by changing incidence angle.  相似文献   

2.
离子液体中电沉积制备钴纳米线阵列   总被引:2,自引:2,他引:0  
Porous anodic alumina (PAA) was used as a template to prepare Co nanowires array from 1-ethyl-3-methylimidazolium chloride ionic liquid by direct current method. The surface morphology of porous anodic alumina template was observed by field emission-scanning tunneling microscopy (FE-SEM) before and after the electrodeposition of Co nanowires. The electrodeposition of Co nanowires was characterized by transmission electron microscopy (TEM) and X-ray powder diffraction (XRD). TEM results indicate that the Co nanowire surface is coarse and porous when aqueous solution was used as electrolyte, and the Co nanowire deposited from the ionic liquid is uniform and smooth. XRD results show that the electrodeposition of Co is a mixture of crystal and microcrystal phase.  相似文献   

3.
Two-dimensional arrays of Cu and Au nanowires have been fabricated by template synthesis method, using the anodic aluminum oxidation films as the template. The morphology of the nanowire array was monitored by atomic force microscope (AFM) in the dissolution processes of the alumina film. Based on the probe molecule strategy, the spectral feature of SCN- adsorbed at the Cu and Au nanowires with different diameters has been investigated by surface enhanced Raman spectroscopy (SERS). The results reveal that the intensity of the SERS bands depends on the length of the exposed nanowires. The C≡N stretching vibration frequency (νCN ) of SCN- up-shifted significantly with the increase of the diameter of the nanowires in the range of 15 nm to 50 nm. This interesting phenomenon is briefly discussed.  相似文献   

4.
Self-ordering of the cell arrangement of the anodic porous alumina was preared in oxalic acid solution at a constant porential of 40V and a temperature of 20℃. The honeycomb structure made by one step anodization method and two step anodization method is different. Pores in the alumina film prepared by two step anodization method were more ordered than those by one step anodization method.  相似文献   

5.
The composition and properties of the anodic films formed on Pb and Pb-3at.%Sb alloy at -0.10 V (vs. Hg/HgO) for 2.5 h in 0.1 mol.dm-3 NaOH solution (25℃) were investigated by cyclic voltammetry, linear sweep voltammetry, open circuit decay curve, photocurrent technique, X-ray diffraction (XRD) and scanning electron microscopy (SEM). It was found that the anodic film formed oh Pb mainly consists of t-PbO, while that on Pb-3at.%Sb consists of o-PbO, t-PbO and a small amount of orthorhombic Sb2O3. The dominant component of the film anodically grown on Pb-3at.%Sb for less than 5 min is o-PbO, however, t-PbO is the major component of the anodic film formed for 1 h or longer. It is established that Sb suppresses the growth of t-PbO. The anodic film formed on Pb-3at.%Sb is less porous than that on Pb. The bandgap energies of t-PbO and o-PbO in the films were determined by photocurrent measurements to be 1.83-1.84 eV and 2.60 eV, respectively.  相似文献   

6.
严学俭 《高分子科学》2009,27(4):479-485
The dependence of polarization fatigue on crystallinity of vinylidene fluoride and trifluoroethylene copolymer films was studied.Experimental data indicated that the higher the crystallinity of the film was,the slower the fatigue rate of the film became.A possible explanation was put forward,and it was regarded that the space charges,trapped at the boundaries of crystallites and/or captured by the defects lying both in amorphous and crystalline phases,should make the major contribution to polarization fa...  相似文献   

7.
Fe(II) was deposited into the bottom of the mesopores of highly ordered large caged cubic mesoporous silica by electrodeposition. And the deposited Fe mesoporous silica thin film was treated by 1%―4% HF to remove the SiO2 template and then calcined. It was found that nanowire bundles, dendritic plates of porous iron oxide, dense parallel backbones of porous iron oxide were obtained at 1.4―-1.6 V and 0.08―0.1 mol/L electrolyte concentration after calcinations; the dendritic pattern of porous iron oxide film ...  相似文献   

8.
Well ordered porous anodic alumina (PAA) film was prepared on pure Al substrate using sulfuric/oxalic acid mixture as electrolyte with different ratios, the best regular PAA film with an average diameter of 45 nm was obtained using 1∶1 sulfuric/oxalic (molar concentration) mixed acid at 26 V. Addition of oxalic acid into sulfuric acid electrolyte resulted in the increase of anodizing current density, indicating a faster formation rate of PAA film. In 1∶1 sulfuric/oxalic acid electrolyte, the current density was the biggest, which illustrated that the formed barrier layer was the thinnest. Besides, addition of oxalic acid increased the stress of oxide film, accordingly changed the self-organized process of PAA film. XPS results indicate that the PAA film is mainly composed of amorphous alumina independent of oxalic acid addition.  相似文献   

9.
孙秀玉 《高分子科学》2014,32(2):130-136
Poly(3-(2-methoxyphenyl)thiophene) (PMP-Th) nanowires were fabricated using porous anodic alumina (PAA) as template through electrochemical polymerization by cyclic voltammetry. The control on the size of nanowires was confirmed by electron microscopy. The results indicated that the luminescence spectra of PMP-Th nanowires in PAA nanochannels were blue-shifted and emission intensity was enhanced compared to the emission of the PMP-Th film. Moreover, the luminescent spectra of PMP-Th nanowires were size dependent, which may result from the change in the degree of confinement of nanowires in PAA. F6rster energy transfer from PAA to PMP-Th molecules is considered to be responsible for the enhancement of luminescence from PMP-Th nanowires in PAA. The results show that the emission properties of polymers with nanostructures can be tuned by controlling their size.  相似文献   

10.
循环伏安法制备Ag纳米线阵列   总被引:5,自引:0,他引:5       下载免费PDF全文
In this paper, highly ordered anodic aluminum oxide (AAO) template with hexagonal close-packed arrays was successfully fabricated through a two-step anodization process. Ag nanowire arrays with high aspect ratio were prepared using cyclic voltammetry within the confined nanochannels of AAO template. In addition, standing Ag nanowire arrays free-support of templates were also fabricated successfully by cyclic voltammetry method. The micrographs and crystal structures of Ag nanowires were studied by field emission scanning electron microscope (FESEM) and X-ray diffraction (XRD). FESEM observation showed that the Ag nanowire arrays with high aspect ratio lie orderly on the surface of the substrate. The diameter of the Ag nanowire is about 60 nm and the length up to 30 μm or more. While the controlled nanowire arrays exhibit highly ordered structure in large area and the standing Ag nanowire in the array has the length of 1 μm and good orientation. XRD results illustrated that the Ag nanowires in the arrays deposited by cyclic voltammetry method have a face centered cubic structure and are preferentially oriented in the (220) direction.  相似文献   

11.
Cu/PAA复合膜的偏振特性   总被引:1,自引:0,他引:1  
应用扩孔和增大阳极氧化电压的方法制备了不同孔径的多孔铝模板,并以交流电沉积法在该模板沉积铜纳米线.测量了铜/多孔铝复合膜的透射光谱和偏振光谱.实验表明,扩孔和增加阳极氧化电压都使样品的透射率下降,但扩孔不能提高它的偏振性能;提高模板氧化电压则可以提高样品的消光比,且消光比随纳米线直径的增加而增加.  相似文献   

12.
Copper metal is in theory a viable oxidative electrocatalyst based on surface oxidation to CuIII and/or CuIV, but its use in water oxidation has been impeded by anodic corrosion. The in situ formation of an efficient interfacial oxygen‐evolving Cu catalyst from CuII in concentrated carbonate solutions is presented. The catalyst necessitates use of dissolved CuII and accesses the higher oxidation states prior to decompostion to form an active surface film, which is limited by solution conditions. This observation and restriction led to the exploration of ways to use surface‐protected Cu metal as a robust electrocatalyst for water oxidation. Formation of a compact film of CuO on Cu surface prevents anodic corrosion and results in sustained catalytic water oxidation. The Cu/CuO surface stabilization was also applied to Cu nanowire films, which are transparent and flexible electrocatalysts for water oxidation and are an attractive alternative to ITO‐supported catalysts for photoelectrochemical applications.  相似文献   

13.
We report the assembly properties of high density and high aspect ratio metal nanowire arrays (Au, Cu and Ag with diameters ranging from 40 to 250 nm) after release from the anodic alumina oxide (AAO) templates. Individual Ag and Cu nanowires were observed following release from the template, however, in the case of gold nanowires, the dispersion was dependent on size and aspect ratio. 40-100 nm gold wires aggregated to form bundles or disordered mats. We show that a simple cyanide-mediated release from the AAO template, results in isolated dispersion of wires even for the smallest wire diameters. Possible stabilising mechanisms for observed tendency of nanowires dispersion are discussed.  相似文献   

14.
Porous anodic oxides generated on copper‐containing aluminium alloys are less regular than anodic oxides generated on pure aluminium. Specifically, a porous oxide morphology comprising layers of embryo pores, generated by a cyclic process of oxide film growth and oxygen evolution, is generally observed. In this work, the relation between the oxidation behaviour of copper during anodising and the specific porous oxide film morphology was investigated by electrochemical techniques, transmission electron microscopy and Rutherford backscattering spectroscopy (RBS). It was found that the anodising potential determines the oxidation behaviour of copper, and the latter determines the porous oxide morphology. At low voltage, relatively straight pores with continuous cell walls were obtained on Al? Cu alloys, but selective oxidation of aluminium atoms resulted in the occlusion of copper‐containing metallic nanoparticles in the anodic film. At higher potentials, copper oxidation promoted oxygen evolution within the barrier layer, and generation of a less regular film morphology. RBS, performed on Al? Cu alloy specimens, revealed a high volume fraction of copper atoms in the anodic films generated at low potentials and a reduced amount of copper atoms in the anodic oxide films generated at high potentials. Copyright © 2009 John Wiley & Sons, Ltd.  相似文献   

15.
We report that the morphologies of porous anodic alumina films are affected significantly by the presence of small amounts of copper impurity in the aluminium substrate, resulting in generation of defects during anodizing in phosphoric acid over a wide range of conditions. The copper is accumulated at the metal/film interface and transported preferentially to triple points of the alumina cells, where oxygen gas is generated leading to development of gas-filled voids.  相似文献   

16.
The effect of tungsten species on the incorporation and migration of phosphorus species within anodic alumina is investigated. The study employs barrier anodic films, formed on a sputtering‐deposited Al‐15at.%W alloy in phosphate electrolytes. The films consist of either an outer tungsten‐containing region and an inner tungsten‐free region, or a tungsten‐containing region only. Phosphorus species are shown to migrate inward in the tungsten‐containing alumina more slowly than in the tungsten‐free alumina. In contrast, the outward migration of tungsten species is relatively unaffected by the presence of phosphorus species. The relevance of the results to the use of tungsten tracers for the study of porous film growth is discussed. Copyright © 2010 John Wiley & Sons, Ltd.  相似文献   

17.
An effective procedure for the fabrication of patterned nanowire arrays with micron-sized features is presented. Photolithographic methods are utilized to form set patterns onto porous anodic alumina membranes (AAM), and these modified membranes can then be used in the electrochemical growth of nanowire arrays. This approach readily allows the formation of a variety of nanowire array patterns with line widths down to several microns.  相似文献   

18.
氧化铝纳米线的制备及其形成机理   总被引:10,自引:0,他引:10  
采用二次铝阳极氧化技术, 制备高度有序的铝阳极氧化膜(AAO模板). 经X射线衍射(XRD)分析, 模板为无定形结构. 将模板放入腐蚀液中, 可获得大量无定形结构的氧化铝纳米线. 模板在800 ℃下退火4 h后, 变为γ-Al2O3结构, 采用类似腐蚀液溶解模板, 得到大量γ-Al2O3纳米线. 研究了腐蚀液种类、腐蚀时间和模板晶体结构等因素对生成氧化铝纳米线的影响, 并利用扫描电子显微镜(SEM)、透射电子显微镜(TEM)和XRD对纳米线的形貌与结构进行了表征. 结果表明, 在多种腐蚀液中, 均可获得氧化铝纳米线; 随着腐蚀时间的增加, 纳米线的长度增加, 直径变小, 长径比增大; 氧化铝纳米线的晶体结构与所采用模板的晶体结构一致. 此外, 还采用原子力显微镜(AFM)和SEM对AAO膜的表面形貌及其结构特点进行了详细的观测, 并以此为基础讨论了氧化铝纳米线的形成机理, 认为AAO模板本身存在的花状微结构是形成纳米线的内因, 花瓣间的凹陷部位首先被腐蚀断裂, 形成氧化铝纳米线.  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司    京ICP备09084417号-23

京公网安备 11010802026262号