Electrochemical Fabrication of Pd-Ag Alloy Nanowire Arrays in Anodic Alumina Oxide Template

The synthesis of Pd-Ag alloy nanowires in nanopores of porous anodic aluminum oxide （AAO） template by electrochemical deposition technique was reported. Pd-Ag alloy nanowires with 16%-25% Ag content are expected to serve as candidates of useful nanomaterials for the hydrogen sensors. Scanning electron microscopy （SEM） and energy dispersed X-ray spectroscopy （EDX） were employed to characterize the morphologies and compositions of the Pd-Ag nanowires. X-ray diffraction （XRD） was used to characterize the phase properties of the Pd-Ag nanowires. Pd-Ag alloy nanowire arrays with 17.28%-23.76% Ag content have been successfully fabricated by applying potentials ranging from -0.8 to -1.0 V （vs SCE）. The sizes of the alloy nanowires are in agreement with the diameter of AAO nanopores. The underpotential deposition of Ag＋ on Pd and Au plays an important role in producing an exceptionally high Ag content in the alloy. Alloy compositions can still be controlled by adjusting the ion concentration ratio of Pd^2＋ and Ag＋ and the electrodeposition processes. XRD shows that nanowires obtained are in the form of alloy of Pd and Ag.

Preparation of well-aligned carbon nanotubes/silicon nanowires core-sheath composite structure arrays in porous anodic aluminum oxide templates

The well-aligned carbon nanotubes (CNTs) arrays with opened ends were prepared in ordered pores of anodic aluminum oxide (AAO) template by the chemical vapor deposition (CVD) method. After then, silicon nanowires (SiNWs) were deposited in the hollow cavities of CNTs. By using this method, CNTs/SiNWs core-sheath composite structure arrays were synthesized successfully. Growing structures and physical properties of the CNTs/SiNWs composite structure arrays were analyzed and researched by the scanning electron microscopy (SEM), transmission electron microscopy (TEM) and X-ray diffraction spectrum (XRD), respectively. The field emission (FE) behavior of the CNTs/SiNWs composite structure arrays was studied based on Fowler-Nordheim tunneling mechanism and current-voltage (I-V) curve. And the photoluminescence (PL) was also characterized. Significantly, the CNTs/SiNWs core-sheath composite structure nanowire fabricated by AAO template method is characteristic of a metal/semiconductor (M/S) behavior and can be utilized to synthesize nanoscale PN junction or Schottky diode device. This process also could be useful for the fabrication of SiNWs and other nanoscale core-sheath composite structure nanowires with chemically inert interfaces for nanoscale electronic and device applications where surface oxidation is undesirable. The diameters and lengths of nanoscale composite structure arrays can be dominated easily, and the experimental result shows that the curling and twisting structures are fewer than those prepared by other synthesized methods.

Synthesis of ordered Si nanowire arrays in porous anodic aluminum oxide templates

Highly ordered poly crystalline Si nanowire arrays were synthesized in porous anodic aluminum oxide (AAO) templates by the chemical vapor deposition (CVD) method. The morphological structure, the crystal character of Si nanowire arrays and the individual nanowire were analyzed by the transmission electron microscopy (TEM), scanning electron microscopy (SEM), atom force microscopy (AFM) and the X-ray diffraction spectrum (XRD), respectively. It is shown that most fabricated silicon nanowires (SiNWs) tend to be assembled parallelly in bundles and constructed with highly orientated arrays. This method provides a simple and low cost fabricating craftwork and the diameters and lengths of SiNWs can be controlled, the large area Si nanowire arrays can be achieved easily under such a way. The curling and twisting SiNWs are fewer than those by other synthesis methods.

Magnetic nanowires fabricated by anodic aluminum oxide template—a brief review

Anodic aluminum oxide （AAO） with highly ordered nanoscale pores which are monodisperse and mutually parallel can be produced through a self-organized electrochemical process. Subsequent deposition of materials into the nanopores produces AA0 embedded nanowire arrays. Whilst the templates can be further removed to obtain free individual nanowires, the em- bedded nanowires form an interesting nanocomposite structure. Recent research activities on the fabrication and characteriza- tion of AAO template based magnetic nanowires are reviewed in this article. Studies of specific systems are given as an exam- ple of the research in the area.

Carbon nanotubes prepared by anodic aluminum oxide template method

One of the most unique structural characteristics of carbon nanotubes(CNTs) differentiating from other carbon materials is their hollow nanochannles,which can be utilized for encapsulating and loading foreign matters.The anodic aluminum oxide(AAO) template technique enables the diameter,length,and cap structure control of the replicated CNTs,and thus shows advantages in pore structure control over the traditional CNT growth approaches.This review details the synthesis of CNTs with tunable diameter,length,wall thickness,and crystalline by using the AAO template method.The doping of heteroatoms and filling of foreign matters into AAO-CNTs are also addressed.Moreover,the main challenges and developing trends of the AAO template method are discussed.

Highly ordered TiO_2 nano-pore arrays fabricated from a novel polymethylmethacrylate/polydimethylsiloxane soft template

A novel soft polymer template containing a double-layer structure,which includes a thin layer of polymethylmethacrylate(PMMA)used as a pattern layer and a thicker layer of polydimethylsiloxane(PDMS)used as a back layer,was fabricated from a replica molding process.Anodic aluminum oxide(AAO)template was used as the replica mold to be replicated to the polymethylmethacrylate layer by a thermal infiltration process under a vacuum condition.Results indicate that PMMA/PDMS soft templates with different sizes could be easily fabricated from the as-prepared AAO replica mold.The PMMA/PDMS soft templates were then employed to imprint a TiO_2 gel for achieving TiO_2 nano-pore arrays.After the imprinting process,the PDMS layer was firstly peeled off and the PMMA layer was then removed into acetonitrile,which can avoid any demolding problems like damages or distortions.The TiO_2 nano-pore arrays with the crystalline of anatase could be obtained at a heat treatment temperature of 450°C.

Controlled synthesis of highly ordered CuO nanowire arrays by template-based sol-gel route

The highly ordered CuO nanowire arrays of composite-oxides were synthesized within a porous anodic aluminum oxide(AAO) template by a citrate-based sol-gel route. A vacuum system was applied to draw the gel into the template pores, which conquers the only driving force of this technique—capillary action, then the gel was thermally treated to prepare desired CuO nanowires. The results of scanning electron microscopy(SEM) indicate that the CuO nanowires are very uniformly assembled and parallel to each other in the pores of the anodic aluminum oxide(AAO) template membranes. The results of X-ray diffraction(XRD) and the selected-area electron diffraction(SAED) indicate that the CuO nanowires are monoclinic-type crystalline structure. Furthermore, X-ray photoelectron spectroscopy (XPS) demonstrates that the stoichiometric CuO is formed.

Synthesis of carbon nanotube arrays using ethanol in porous anodic aluminum oxide template

Carbon nanotube (CNT) arrays confined by porous anodic aluminum oxide (AAO) template were synthe- sized using ethanol as reactant carbon source at low pressure. Images by scanning electron microscope (SEM) and low magnification transmission electron microscopy (TEM) show that these CNTs have highly uniform outer diameter and length, absolutely controlled by the diameter and depth of nano-channel arrays of the AAO. High resolution transmis- sion electron microscopy (HRTEM) imaging indicates that the graphitization of the CNT walls is better than the results reported on this kind of template-based CNT arrays, al- though it is not so good as that of multiwalled carbon nano- tubes (MWCNTs) synthesized by catalysis. CNTs synthesized using acetylene as reactant gas show much less graphitiza- tion than those prepared using ethanol by comparing the results of HRTEM and Raman spectroscopy. The etching effects of decomposed OH radicals on the amorphous carbon and the roughness of AAO nano-channel arrays on the CNTs growth were employed to explain the graphitization and growth of the CNTs.

Electroless Deposition of Nickel Nanowire and Nanotube Arrays as Supports for Pt-Pd Catalyst for Ethanol Electrooxidation

Nickel nanowire and nanotube arrays as supports for Pt-Pd catalyst were prepared by elec- troless deposition with anodic aluminum oxide template. Pt-Pd composite catalyst was de- posited on the arrays by displacement reaction. SEM images show that the nickel nanowires have an average diameter of I00 nm and the nickel nanotubes have an average inner diameter of 200 nm. EDS scanning reveals that elemental Pt and Pd disperse uniformly on the arrays. Cyclic voltammetry study indicates that the nickel nanotube array loaded with Pt-Pd pos- sesses a higher electrochemical activity for ethanol oxidation than the nickel nanowire array with Pt-Pd.

模板法制备枝状Pt纳米线

Porous anodic aluminum oxide（AAO） templates, obtained by anodization of aluminum sheets at relatively high voltages, were used for fabricating branched platinum nanowires which copy the three-dimensional branching structure of the nanochannels in the template. The formation of these branched nanochannels is the characteristic of AAO templates grown at 60 V in 0.15 mol/L H2C2O4 solution. When AAO templates are grown at 40 V or lower, straight channels and platinum nanowires are obtained. Platinum nanowires array was alter-current（AC）-electrodeposited in AAO at a lower frequency（20 Hz） and increasing voltage（5-15 V）. Compared with traditional AC electrodeposition condition, the deposition rate of platinum nanowires under this condition is slower and more controllable. Therefore, the platinum nanowires can perfectly copy the structure of the template. The as-obtained Al/AAO/Pt composite and branched platinum nanowires were characterized by X-ray diffraction（XRD） and transmission electron microscope（TEM）, respectively.

阳极氧化铝模板法制备纳米电子材料

阳极氧化铝模板具有容易制备、成本低、孔道分布均匀等特点,是制备形状高度均匀、有序纳米电子材料的理想无机模板。该模板法制得的金属、半导体和非金属纳米材料具有不同于母材的光、电、磁等特殊性能,在新型电子材料的开发方面具有广阔的应用前景。文中介绍了该模板的阳极氧化工艺、成膜机理以及不同的电解液、氧化电流、电压等因素对模板的纳米孔道生长的影响。分析了纳米材料的直流电沉积和交流电沉积的电化学机理和沉积速率的影响因素。

水热法制备TiO_2纳米管阵列

在(NH4)2TiF6的水溶液中,以铝基阳极氧化铝膜为模板,采用水热法制备了TiO2纳米管阵列.采用场发射扫描电镜、X射线能量色散谱及X射线光电子能谱对所得纳米管阵列进行了表征,并探讨了其形成机制.结果表明,控制水热处理时间对制备形貌规整的纳米管阵列至关重要,较佳的水热处理时间为90min.采用本方法制备的纳米管阵列具有特殊的形貌,即表面的连续多孔结构和断面的不连续、分离的管状特征.这种特殊形貌的形成是由于[TiF6]2-与阳极氧化铝模板的表面和断面具有不同的反应速率,水解产物优先在阳极氧化铝模板的表面沉积所致.

硫化镉纳米线的电沉积制备及表征(英文)

以不同孔径的多孔阳极氧化铝为模板，采用直流电沉积的方法，在含CdCl2和S的DMSO溶液中制备出了CdS纳米线．SEM、TEM表征的结果表明，在不同孔径的多孔阳极氧化铝模板中，通过沉积时间等条件的控制，制得直径不同、长度可达5μm的平行结构、均匀而连续的CdS纳米线阵列．电子衍射和能谱结果显示所得的纳米线属于六方晶系CdS，线中Cd和S原子比接近1：1．

模板法制备高度有序的聚苯胺纳米纤维阵列

近年来, 利用化学或物理方法制备多种材料的纳米有序阵列复合结构已成为学术界的研究热点. 用具有纳米孔洞的模板(多孔阳极氧化铝、多孔硅以及聚碳酸脂膜)制备的金属、半导体、碳纳米管等材料的纳米有序阵列复合结构已在润滑、微电极、单电子器件、传感器、垂直磁记录、场致电子发射等方面显示了诱人的应用前景[1～3]. 由于导电聚合物具有良好的电学、光学以及氧化还原特性, 因此在近20年里一直备受关注. 利用模板法制备的纳米结构的导电聚合物材料的电导率比常规法得到的粉体或薄膜结构的同类材料高几个数量级[4,5]. Martin研究小组先后用模板法合成了聚吡咯[6,7]、聚(3-甲基噻吩)[6]以及其它聚合物[8,9]纳米材料; Schultze等[10]研究了导电聚合物的微结构. 聚苯胺(PANI)作为一种高聚物材料, 具有稳定性好、易于合成等优点, 在化学传感器、显示器、光电池等光电器件上有许多潜在应用价值. 本文利用多孔阳极氧化铝(AAO)模板, 制备出高度有序的PANI纳米纤维阵列, 通过扫描电子显微镜(SEM)对PANI纳米纤维阵列进行形貌的观察, 利用X光电子能谱(XPS)对PANI/AAO复合结构进行元素分析, 为PANI纳米纤维的制备提供了较有力的证据.

阳极氧化铝模板上热扩散法制备MoO_x纳米阵列

采用简单的热扩散法,MoO3可在模板纳米孔道内有序生长,经还原后获得MoO2和金属Mo纳米管/线阵列.运用XRD、SEM、TEM、HRTEM等技术对产物进行了表征.结果表明:在70 nm孔径的阳极氧化铝模板上,H2/N2气氛下600℃时的还原产物为单晶MoO2;而在50 nm的模板上,同样条件的还原产物为MoO2微晶聚合体.乙醇的加入能够大大改善产物的形貌.H2气氛,650℃以上温度下进一步还原得到了金属Mo纳米管阵列.

氧化铝模板上定向纳米碳管的快速生长及超声切短

在阳极氧化铝(AAO)模板上电沉积催化剂,快速生长了定向纳米碳管,纳米碳管以顶部生长模式生长.采用了超声的方法来切短露头于AAO模板的纳米碳管,增加纳米碳管膜的定向性.结果显示随着超声时间的增加,纳米碳管的定向性增加.位于纳米碳管膜顶部的催化剂在碳管切短的同时被去除,得到了顶部开口的纳米碳管.解释了纳米碳管被超声切短的机理.

氧化铝多孔膜的制备及其应用研究新进展

全面归纳和分析了铝阳极氧化技术的机理、工艺、Al2O3多孔膜的生长规律及制备技术,详细介绍了Al2O3多孔膜在模板合成一维TiO2半导体光催化材料及零维纳米点阵列周期调制薄模等方面的最新研究成果,并对Al2O3多孔膜及模板合成TiO2光催化材料的发展前景进行了展望。

多孔阳极氧化铝膜在纳米功能材料制备中的应用

纳米材料具有一系列不同于块体材料的新异特性 ,在许多领域都有着广阔应用前景。阳极氧化铝膜具有独特的多孔结构 ,可作为制备各种纳米功能材料的模板 ,因而在纳米功能材料制备中占有重要地位。本文综述了多孔阳极氧化铝模板的结构特征、制作方法及由模板合成法制备的多种纳米功能材料的研究与应用现状 。

随机分布Fe纳米线复合材料的吸波性能

在具有纳米级孔洞的多孔氧化铝模板上, 用电沉积方法制备出α Fe纳米线有序阵列组装膜。用 10%NaOH将纳米线溶液解离, 并使之与树脂混合均匀, 制成随机分布Fe纳米线 /绝缘体复合吸波材料, 并对其吸波性能进行了研究。研究结果表明: 随铁纳米线体积分数的提高, 随机分布的Fe纳米线 /绝缘体复合吸波材料的电磁参数也随之增大; 用测试电磁参数计算了不同厚度的反射率, 体积分数为 25%随机分布的铁纳米线 /绝缘体的复合吸波材料最佳吸收厚度为 1 14mm; 在 9 7GHz时, 反射率达 -45dB, 小于 -5dB时, 反射率带宽达到9GHz; 随铁纳米线 /绝缘体的复合吸波材料厚度的增加, 吸收峰位向低频移动; 随铁纳米线体积分数的增加, 其吸收率明显增大, 同时最佳吸收厚度也减小。

阳极氧化工艺制备氧化铝模板

多孔氧化铝模板是一种用于制作纳米结构材料的模板.为了制作出理想的模板,采用不同的阳极氧化工艺制备多孔氧化铝模板,通过改变工艺参数研究了模板孔径的变化规律,结果表明,在适宜条件下,纳米级氧化铝模板具有六方紧密堆积柱状结构,在每个六棱柱的中心有一个与膜表面垂直的圆柱孔.在一定范围内,随着氧化电压、电流密度、反应温度、铝片纯度的增加氧化铝模板的孔径也随之增加.