In-situ heating study on the structural change of surfactant-templated germanium oxide mesostructure

Mesostructured germanium oxide has been well-synthesized by using a surfactant-templated approach under basic hydrothermal conditions. The cationic surfactant cetyltrimethylammonium bromide (CTAB) has formed nanotubes with uniform diameter of about 3.2 nm. Blanket-like morphology of the as-prepared sample has been observed with transmission electron microscopy (TEM). High-resolution TEM image reveals that the nanotubes are connected with inorganic germanium oxide and have self-assembled into periodic mesostructure. In-situ heating X-ray diffraction (XRD) patterns confirm that the germanium oxide is in amorphous phase in the temperature range from room temperature (RT) to 700 degrees C. In-situ heating small-angle X-ray scattering (SAXS) presents the mesostructural change with temperature. The local atomic structures around germanium atom have been obtained with in-situ heating X-ray adsorption fine structure (XAFS) techniques. The stability of this mesostructure has been determined to be correlated with the cationic surfactant CTAB. The structural evolution from the GeO 2/NaOH aqueous solution, the as-prepared sample to the sample heated at 700 degrees C, has been described, and the formation mechanism of mesostructured germanium oxide has been discussed.     

一种新的WO3纳米管的制备方法

一维纳米材料因可用来构造高性能纳米器件的结构单元而成为纳米材料研究的热点．目前的研究重点集中在材料的制备和结构性能表征方面,已发展了多种制备方法,主要有模板法、V-L-S法、L-L-S法和V-S法等,其中阳极氧化铝(AAO)模板法是制备一维材料的好方法．AAO模板的制备工艺已相当成熟,     

Preparation of Polyelectrolyte Nanotubes by a Pressure filter-template Technique Using Microporous Anodic Aluminum Oxide (AAO) as the Template

Polyelectrolyte nanotubes of poly(sodium 4‐styrene‐sulfonate) (PSS) with cationic poly(diallyl dimethyl ammonium chloride) (PDDA) (PSS/PDDA) were fabricated by a pressure‐filter‐template technique using microporous anodic aluminum oxide (AAO) as the template. UV‐Vis spectroscopy, scanning electron microscopy (SEM), transmission electron microscopy (TEM), X‐ray diffraction (XRD) and infrared spectroscopy (FT‐IR) were applied to characterize the obtained PSS/PDDA nanotubes. The results have shown that the PSS/PDDA nanotubes exhibit an amorphous structure and have the outer diameter of 200 nm and length of 25 µm respectively, which are in good agreement with the dimensions of the AAO template pores. The wall thickness of the nanotubes may be controlled by the number of the self‐assembled layers. Formation of the nanotubes follows a layer‐by‐layer (LbL) mechanism due to the electrostatic interactions, where the SO^?₃ groups of PSS are first adsorbed on the Lewis acid sites of AAO template pores.     

Pt纳米线阵列的氧还原催化性能

采用阳极氧化铝(AAO)模板法电化学沉积制备了Pt纳米线阵列(Pt NWs)氧还原催化剂, 通过扫描电子显微镜(SEM)、透射电子显微镜(TEM)和电化学测试对Pt纳米线阵列催化剂的形貌和电催化性能进行了表征. 循环伏安法(CV)研究表明Pt纳米线阵列催化剂的电化学活性面积大于其几何面积; 旋转圆盘电极(RDE)测试研究发现, 制备的Pt纳米线阵列催化剂的氧还原反应(ORR)曲线的半波电势相对Pt/C的有正移, 并且Pt纳米线阵列催化剂的极限扩散电流比Pt/C大.     

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 (/-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     

N,N-双(α-萘基-苯基)-4,4′-联苯二胺纳米管的制备及其光谱行为

利用多孔氧化铝作模板采用熔融法成功制备了一种定向有序排列的有机小分子 (NPB)纳米管 ,并用场发射扫描电镜 (FESEM)、X射线能量损失谱 (EDX)、透射电子显微镜 (TEM)和荧光显微镜对其进行了表征 .发现该纳米管具有整齐的形貌和规整的尺寸 .进一步的研究表明 ,多孔氧化铝模板的亲油亲水处理对能否成功地大量获得纳米管起到非常重要的作用 .值得注意的是 ,在对不同尺寸纳米管材荧光光谱的测定中 ,可明确观察到材料光学性质的尺寸依赖性 .     

Template Synthesis and Characterization of Cu2O/TiO2 Coaxial Nanocable for Photocatalysis

Coaxial nanocable consisted of p-type Cu₂O nanowires and n-type TiO₂ nanotubes arrays was prepared in the porous anodic aluminum oxide(AAO) template via the sol-gel method and subsequent electrodeposition method. X-ray diffraction analysis identified an anatase structure of the TiO₂ nanotubes and cubic structure of the Cu₂O nanowires. The obtained samples were also characterized by scanning electron microscopy(SEM), transmission electron microscopy(TEM) and energy dispersive X-ray spectroscopy(EDS). The diffrence of open circuit potential of the coaxial nanocable electrode was larger than that of the TiO₂ nanotubes electrode under ultraviolet illumination, which means doping with Cu₂O could improve the photovoltage effectively. Meanwhile, nanocable arrays exhibited a high activity for photodegrading Rhodamine B under Xe lamp irradiation and the photocatalysis degradation efficiency was up to 98.69% after degradation for 7 h. The enhanced photocatalytic activity could be attributed to the high migration efficiency of photoinduced electrons, which may suppress the charge recombination effectively.     

大面积Bi单晶纳米线阵列的制备

在有序的氧化铝模板(AAO)的孔洞中, 采用电化学沉积工艺成功地制备了准金属Bi纳米线有序阵列. 使用X射线衍射仪(XRD)、场发射扫描电子显微镜(FE-SEM)、透射电子显微镜(TEM)及高分辨电子显微镜(HRTEM)对样品的结构和形貌进行了表征. XRD结果表明, 所制备的铋样品为六方相, 且沿[110]方向有很好的生长取向; FE-SEM图片清晰地说明铋纳米线阵列是大面积、填充率高和高度有序的; TEM的结果显示纳米线直径均匀、表面光滑且长径比大; HRTEM图片中清晰的晶格条纹和选区电子衍射(SAED)结果表明纳米线是单晶.     

ZnO纳米线阵列的电沉积法制备及表征(英文)

利用直流电沉积方法在多孔氧化铝模板的孔洞中生成锌纳米线,在氧气氛围中,于800°C下氧化2h,将氧化铝中的锌氧化成氧化锌.本研究利用氧气氛围进行锌的氧化,大大提高了传统方法的氧化锌纳米线的制备效率.用场发射扫描电子显微镜(FE-SEM)、透射电子显微镜(TEM)和X射线衍射仪(XRD)对其形貌及成分进行表征和分析,结果表明,氧化铝模板的有序孔洞中填充了大尺寸、均匀连续的多晶态氧化锌纳米线.纳米线具有约1000:1的高纵横比,其长度等于氧化铝模板的厚度,直径约为80nm.光致发光(PL)光谱表明,氧化锌纳米线在504nm处有由于氧空位引起的较强蓝绿光发射.这为进一步研究ZnO/AAO组装体发学性质和开发新型功能器件提供了基础.     

Large-scale synthesis of silver nanowires and platinum nanotubes

Silver nanowires have been synthesized by ethylene glycol reduction of silver nitrate with the assistance of polyvinyl pyrrolidone and sodium sulfide in a large scale. By adjusting the reaction temperature and Na₂S content, silver nanowires with lengths up to 3?4 μm can be achieved in high yield. Scanning electron microscopy, transmission electron microscopy (TEM), high-resolution transmission electron microscopy (HRTEM), selected areas electron diffraction (SAED), and X-ray diffraction (XRD) have been employed to characterize silver nanowires. Platinum nanotubes with length about 3 μm can be prepared using as-prepared silver nanowires as sacrificial templates. Platinum nanotubes were characterized by TEM, SAED, and HRTEM.     

Nanoparticle films as a conducting layer for anodic aluminum oxide template-assisted nanorod synthesis

A simple, inexpensive, and robust methodology was developed to fabricate conductive film substrates by mechanically packing nanoparticles (NPs) on one side of anodic aluminum oxide (AAO). Gold, silver NPs, and carbon nanotubes were used as building blocks in the synthesis of conductive film substrates, upon which perpendicular nanorod arrays and colloidal free-standing nanorods were easily constructed. Characterizations by field emission scanning electron microscopy (FE-SEM) and optical dark-field microscopy confirmed the validity of the conductive NP film substrates on the AAO template. This contribution could provide a convenient and low-cost means for the fabrication of various conductive substrates on AAO.     

Template-directed synthesis of ordered iron pyrite (FeS2) nanowires and nanotubes arrays

Highly ordered iron pyrite (FeS₂) nanowires and nanotubes arrays have been fabricated by using sol–gel method with AAO templates. The prepared nanowires and nanotubes have uniform lengths and 200 nm diameters. Their crystal phase was identified as cubic FeS₂ by using X-ray diffraction, Raman spectroscopy, high-resolution transmission electron microscopy and selected-area electron diffraction pattern. The direct optical band gaps of the as-prepared FeS₂ nanowires were 0.98 and 1.23 eV, respectively, indicating their suitability for photovoltaic application.     

Generation of hydrophilic, bamboo-shaped multiwalled carbon nanotubes by solid-state pyrolysis and its electrochemical studies

A simple, efficient, and novel method was developed for the direct preparation of hydrophilic, bamboo-shaped carbon nanotubes by the pyrolysis of ruthenium(III) acetylacetonate in a Swagelock cell is reported. The obtained product exhibits mostly bamboo-shaped, straight, periodic twisted, multiwalled carbon nanotubes possessing diameters of 50-80 nm and lengths of around 10 microm. The pyrolyzed product was characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), high resolution TEM (HRTEM), Fourier transform infrared (FT-IR), X-ray photoelectron spectroscopy (XPS), micro-Raman, and cyclic voltammetric techniques. HRTEM studies showed that the walls of bamboo-shaped carbon nanotubes consisted of oblique grapheme planes with respect to the tube axis. The interlayer spacing between two graphitic layers was found to be 0.342 nm. XPS measurements have suggested that as-prepared carbon nanotubes consist the surface functional groups on the surface of carbon nanotubes. The electrochemical properties of synthesized carbon nanotubes have been evaluated. Thermogravimetric analysis (TGA), IR, and cyclic voltammetric studies showed the presence of oxygen functionalities. Raman studies revealed the presence of disorder in the graphitic carbon and the presence of exposed edge plane defects in the generated carbon nanotubes for influencing the surface behavior and electrochemical properties. The electrochemical behavior of electrodes made of bamboo-shaped carbon nanotubes served for an oxygen reduction reaction.     

基于层层自组装的CuTsPc/DPDCH纳米管的制备

在阳极多孔氧化铝模板中利用层层自组装技术制备出了高度有序的聚电解质磺化酞菁铜(CuTsPc)/4,4′-联吡啶盐酸盐(DPDCH)纳米管, 并对其组装过程用UV-Vis, XRD和FT-IR进行了分析, 纳米管的微观形貌通过SEM和TEM进行表征. 结果表明, 第一层 CuTsPc和第二层DPDCH在AAO模板上的沉积平衡时间均约为60 min, 沉积过程主要有三个阶段: 模板孔外的吸附过程、孔内扩散控制的沉积过程和孔内表面沉积控制过程. CuTsPc主要以磺酸根吸附于AAO模板上. CuTsPc/DPDCH纳米管为非晶态体系. CuTsPc/DPDCH纳米管的外径和壁厚分别为200和20 nm, 外径受控于AAO模板的孔径, 壁厚与组装的层数有关, 利用此方法还可以制备其他带有相反电荷的有机小分子对纳米管或纳米线.     

WO3纳米管的模板法制备及表征

0引言 WO3纳米材料具有光致变色、电致变色、气致变色等特性,可用于光学信息和储存显示器、pH值探测器、气敏传感器、灵敏窗口等[1,2];并且在太阳能的储存与利用、光电转换、光催化降解大气和水中的污染物等方面有着广阔的应用前景[3,4],成为近几年重点研究的半导体材料之一.以前纳米WO3的制备主要集中在薄膜上,其薄膜的制备工艺已经相当成熟,主要包括蒸发法、溅射法、CVD法、喷涂法、阳极氧化法、溶胶-凝胶法等[3].     

Ni(OH)2纳米管的制备、表征及电化学性能

以多孔氧化铝为模板, 在不同溶液浓度下, 用化学沉积法制备了氢氧化镍纳米管. 采用XRD, SEM, TEM和HRTEM等手段, 对产物的物相、表面形貌及微结构进行了表征. 结果表明所得产物是高纯度的氢氧化镍纳米管, 外径约为180～220 nm, 管壁厚20～30 nm. 将所制备的氢氧化镍纳米管制成电极, 其电化学性能测试表明, Ni(OH)₂纳米管的中空结构特点, 能够有效地提高镍电极的充电效率、放电比容量、高倍率及高温放电性能. 机理分析表明中空结构的Ni(OH)₂纳米管对于提高碱性二次电池的综合性能有着极为重要的意义.     

Self-assembling vanadium oxide nanotubes by organic molecular templates

Vanadium oxide nanotubes were synthesized as the main product by hydrothermal self-assembling from ammonium metavanadate (NH(4)VO(3)) and organic molecules as structure-directing templates. Several kinds of templates including primary amines (C(n)H(2n+1)NH(2)), alpha,omega-diamines (H(2)N[CH(2)](n)NH(2)), and quaternary ammonium salt (CTAB) were demonstrated to be appropriate for the formation of nanotubes. The morphologies and structures of the nanotubes were characterized by X-ray powder diffraction (XRD), transmission electron microscopy (TEM), high-resolution transmission electron microscopy (HRTEM), and thermal gravimetric analysis (TGA). The nanotubes were found forming together with the layered structures and the sheetlike structures. On the basis of the growth mechanism of WS(2) nanotubes proposed by our group, a possible rolling mechanism was proposed, which might be a suitable general formation mechanism for types of nanotubes from lamellar structures.     

铅纳米线阵列的制备

使用电化学沉积方法,在有序的氧化铝模板(AAO)孔洞中制备了铅纳米线有序阵列。用X射线衍射仪(XRD)、场发射扫描电子显微镜(FE-SEM)、透射电子显微镜(TEM)对样品的结构、形貌、进行表征和观测。XRD的结果表明所制备的样品为纯的立方面心铅,且纳米线生长沿<220>有很好的取向。FE-SEM的图片清晰地说明铅纳米线阵列是大面积、高填充率和高度有序的。TEM的结果显示纳米线直径均匀、表面光滑且长径比大。     

Template-directed synthesis of ordered single-crystalline nanowires arrays of Cu2ZnSnS4 and Cu2ZnSnSe4

Highly ordered quaternary semiconductor Cu(2)ZnSnS(4) nanowires array have been prepared via a facile solvothermal approach using anodic aluminum oxide (AAO) as a hard template. The as-prepared nanowires are uniform and single crystalline. They grow along either the crystalline [110] or [111] direction. The structure, morphology, composition, and optical absorption properties of the as-prepared Cu(2)ZnSnS(4) samples were characterized using X-ray powder diffraction, transmission electron microscopy, energy dispersive X-ray spectrometry, scanning electron microscopy, and UV-vis spectrometry. A possible formation mechanism of the nanowire arrays is proposed. Governed by similar mechanism, we show that Cu(2)ZnSnSe(4) nanowire array with similar structural characteristics can also be obtained.     

New nanotube synthesis strategy--application of sodium nanotubes formed inside anodic aluminium oxide as a reactive template

Formation of Na nanotubes inside the channels of anodic aluminium oxide (AAO) membranes has been achieved by decomposing NaH thermally on AAO. The as-produced material, Na@AAO, is applied as a reactive template to prepare other tubular materials. Reacting Na@AAO with gaseous C6Cl6 generates carbon nanotubes (ca. 250 nm, wall thickness of 20 nm, tube length of 60 microm) inside the AAO channels. Highly aligned bundles of nearly amorphous carbon nanotubes are isolated after AAO is removed.