氧化钕纳米线的制备与表征

以硝酸钕和尿素为主要原料,多孔阳极氧化铝膜(AAO)为模板,分别采用普通浸渗和压力浸渗法制备了氧化钕纳米线.采用扫描电子显微镜(SEM)、透射电子显微镜(TEM),X射线衍射仪(XRD)和能量仪(EDS)对纳米线的形貌,结构及组成进行了表征.结果表明:两种浸渗方法均可得到氧化钕纳米线,压力溶胶浸渗有利于模板纳米孔填充度的提高,可以得到高长径比的氧化钕纳米线.     

阳极氧化铝模板为基底可控制备碳纳米棒

以不负载任何活性组分的阳极氧化铝模板为基底,采用化学气相沉积法在700℃下催化裂解乙炔可控制备纳米碳材料,反应气氛分别为氩气和氢气;产物通过扫描电镜和高分辨透射电镜进行表征.结果表明:当反应气氛为氩气时,阳极氧化铝模板表面沉积了棒体较直的碳纳米棒,这些碳纳米棒形貌规整,平铺在阳极氧化铝模板表面;当反应气氛为氢气时,碳纳米棒的生长方向变成了规整地直立状态;所制备的碳纳米棒为实心的,结构为断断续续的石墨片层组成的波纹状结构.     

溶胶-凝胶法在多孔氧化铝模板中生长纳米氧化锌

以醋酸锌为前驱体,乙醇为溶剂,二乙醇胺为稳定剂,采用溶胶-凝胶法在多孔氧化铝模板中制备纳米氧化锌.实验结果表明,氧化锌首先吸附在模板孔洞的边壁,形核生长,随着反应时间的延长,逐渐填充孔洞,形成密实的氧化锌纳米线.其发光光谱显示出较好的紫外区发光性能.     

糖葫芦状氧化钛纳米线阵列的溶胶-电泳沉积及其形成机理

采用二次阳极氧化工艺制备了高度规则排列的多孔氧化铝(PAA)模板,并利用溶胶-电泳法在PAA模板中制备了糖葫芦状氧化钛纳米线阵列,对纳米线及PAA模板进行了SEM分析.结果表明,纳米线直径在75 nm左右,线间距约为100nm,每根纳米线都具有周期性凹凸,形状与糖葫芦相似.结合胶体颗粒间的相互作用、胶体颗粒在电场作用下的运动、胶体聚沉理论及胶体颗粒的扩散行为等因素,建立了溶胶-电泳沉积的物理模型,阐明了糖葫芦状纳米线阵列的形成机理.     

溶胶一凝胶模板法制备氧化镍纳米线

采用二次阳极氧化的方法,以5%磷酸为电解液,制得具有一定厚度有序性较高的阳极氧化铝模板(AAO),结合溶胶-凝胶法在模板微孔内合成氧化镍纳米线.利用扫描电镜(SEM)对模板和纳米线材料的形貌进行了表征,结果表明:采用该方法成功制得线状的氧化镍,长度可达亚微米级,直径约为100nm,与AAO模板的孔径大小基本一致,因此可以通过调节AAO模板的孔径大小来实现氧化镍纳米线的可控生长.     

溶胶剂对纳米氧化铝粉体特性的影响

以异丙醇铝为原料,分别选用HNO3,NH4OH和NH4HF2作为溶胶剂,采用溶胶凝胶技术制各纳米氧化铝粉体.利用SEM,TEM和XRD等粉体分析和表征手段研究了几种胶溶剂对纳米氧化铝粉体特性的影响规律.结果表明,异丙醇铝水解时加入不同种类和不同量的溶胶剂将大大影响着纳米氧化铝粉体的形貌、粒径和分散性.粒度分析表明异丙醇铝水解时加入HNO3,NH4HF2或NH4OH时所制备的纳米氧化铝粉体的粒径大小与溶胶剂的关系曲线为具有一个最大值点的抛物线.XRD分析表明溶胶剂对粉体的晶型没有影响.扫描电镜和透射电镜分析表明,不同溶胶剂对纳米氧化铝粉体的形貌以及分散性有较大的影响,其中以氨水为溶胶剂时,粉体为絮状,且团聚现象严重;以硝酸为溶胶剂,粉体的分散性有较大提高,大块团聚现象不明显,不过粉体形貌不规则;以氟化氢铵为溶胶剂,颗粒性明显,分散性很好,无大块团聚出现.     

氧化钨纳米颗粒和纳米线的选择合成及光致发光研究

采用无机盐辅助水热法选择调控合成了WO3纳米颗粒和纳米线.通过SEM,TEM,EDX和XRD等手段对产物进行了表征.研究了形貌和尺寸对WO3的光致发光性能的影响,并探讨了形貌和尺寸对WO3光致发光性能影响的机制.     

基于氧化铝模板直接电沉积法镍纳米线的制备与表征

在未氧化铝和氧化铝之间经过降压剪薄阻挡层直接进行电沉积,采用不同电压进行电沉积制备了镍纳米线,并采用SEM,TEM和X射线衍射对所制备的镍纳米线进行了表征,研究了电沉积电压对纳米线结构的影响。结果表明：镍纳米线的外形决定于氧化铝模板的形貌,其直径和最大长度分别依赖于模板孔洞的直径和长度,当电沉积电压为1,1.5和2V时制备的镍纳米线为多晶结构,随着电沉积电压的升高,镍纳米线为沿[220]择优取向的单晶结构（电沉积电压分别为3V和4V）,当电沉积电压进一步升高时,择优取向由[220]转为[111]方向（电沉积电压5V）。     

制备金属离子掺杂二氧化钛纳米线及其可见光催化

采用二次阳极氧化工艺制备了高度有序的多孔氧化铝模板,通过模板法与溶胶.电泳沉积法结合的组装技术,合成了具有高比表面积的糖葫芦状M/TiO2(M=La3 ,Fe3 )纳米线阵列体系.采用SEM对样品进行了表征,测试结果表明Ti02纳米线阵列保持了模板的有序性,直径分布均匀一致,为70 nm左右,长为15μm左右,取向性很好.以甲基橙为目标降解物,在可见光下考察该金属离子掺杂纳米线的催化活性,结果显示此纳米线阵列体系具有非常优良的可见光催化性能,与同条件下制备的薄膜试样相比可见光催化活性可以提高4倍以上.     

阳极氧化铝样模法制备纳米线阵列的发展趋势

在具有纳米孔洞的阳极氧化铝(AAO)模板上，电沉积金属和半导体微粒，可制备出高度有序的一维金属半导体纳米线阵列。样模法制备纳米材料是国内外竞相研究的热点，阳极氧化铝膜以其良好的高密度纳米孔径正逐渐引起人们的关注。     

Synthesis and characterization ofsingle-crystalline alumina nanowires

Alumina nanowires were synthesized on large-area silicon substrate via simple thermal evaporation method of heating a mixture of aluminum and alumina powders without using any catalyst or template. The phase structure and the surface morphology of the as-grown sample were analyzed by X-ray diffractometry(XRD) and scanning electron microscopy (SEM), respectively. The chemical composition and the microstructure of the as-grown alumina nanowires were characterized using transmission electron microscope(TEM). The nanowires are usually straight and the single crystalline has average diameter of 40 nm and length of 3 - 5μm. The growth direction is along the [002] direction. Well aligned alumina nanowire arrays were observed on the surface of many large particles. The catalyst-free growth of the alumina nanowires was explained under the framework of a vapor-solid(VS) growth mechanism. This as-synthesized alumina nanowires could find potential applications in the fabrication of nanodevices.     

Controllable Synthesis of WO3 Nanowires by Electrospinning and Their Photocatalytic Properties Under Visible Light Irradiation

Large amounts of WO3 nanowires were prepared on silicon substrates by electrospinning followed by appropriate calcinations in air using ammonium metatungstate(AMT) as WO3 source. Tunable densities and diameters of WO3 nanowires were achieved by changing the electrospinning time and the concentration of AMT in precursor solution.TG/DSC analysis was used to direct the heating process. The effects of both solvent ratio and heating process on the morphology of the obtained nanowires were investigated. The morphology, structure, and chemical compositions of the tungsten oxide were characterized by SEM, XRD, and EDX, respectively. Results showed that monoclinic phase WO3 nanowires with diameters ranging from 100 to 200 nm were obtained after the appropriate heating process when the AMT concentration of the precursor solution increased from 10 to 20 wt%. The photocatalytic performance of the obtained WO3 nanowires under visible light irradiation([420 nm) was investigated in the degradation of Rhodamine B at room temperature in air.     

Electrochemical synthesis of polypyrrole nanowires in the presence of gelatin

Biotemplating is an emerging, unique approach for the synthesis and organization of the organic or inorganic materials into well-defined nanostructures. In this article, conducting polymer polypyrrole (PPy) nanowires were electrochemically synthesized using a protein molecule, gelatin, as a template. The morphologies, microstructures, chemical compositions, and electrochemical performances of the obtained nanowires were investigated in detail. It was found that the gelatin played an important role in the formation of the PPy nanowires and the morphologies of the nanowires were closely related to the electrodes used. This work not only extended the application of gelatin to the synthesis of the conducting polymer nanowires, but also presented a simple and useful route to the fabrication of PPy nanowires with different length, from normal size to superlong size.     

Alumina nanostructures prepared by two-step anodization process

Alumina nanostructures were obtained by two-step anodization process.The porous anodic aluminum oxide(AAO)membranes were anodized in oxalic acid,which was subsequently treated with chemical etching process with 1.0 mol/L sodiumhydroxide solution,or mixed solution of phosphoric acid(6.0%)and chromic acid(1.8%),respectively.Field emission scanningelectron microscopy(FE-SEM)and transmission electron microscopy(TEM)were employed to character the morphology andstructure of the obtained alumina nanostructure.It is found that alumina nanowires are generated in the acidic chemical etchingsolution,while nanotube structures are formed in the alkaline solution.The influence of acid and alkaline solution on aluminamorphologies in the chemical etching process was discussed.     

Doped and de-doped polypyrrole nanowires by using a BMIMPF6 ionic liquid

We electrochemically synthesized π-conjugated polypyrrole (PPy) nanowires by using an environmentally stable and recyclable ionic liquid, 1-butyl-3-methylimidazolium hexafluorophosphate (BMIMPF₆), as a dopant, based on an anodic alumina oxide (Al₂O₃) nanoporous template. The de-doped states of the PPy nanowires were obtained from doped PPy nanowires through cyclic voltammetry (CV) using a solution of the catalyst in the BMIMPF₆ ionic liquid. We confirmed the de-doped states of PPy nanowires based on a decrease of the bipolaron peak of the ultraviolet and visible (UV–vis) absorbance spectra. The formation of PPy nanowires was visualized by using scanning electron microscopy and transmission electron microscopy. We studied the optical and structural properties of the doped and de-doped PPy nanowires by UV–vis absorbance and Fourier transform-infrared spectra. Our work included obtaining a laser confocal microscope Raman spectra for a single strand of the PPy nanowires.     

Fabrication of cobalt nanostructures with different shapes in alumina template

Two different morphologies of Co nanostructures, such as hollow nanotubes and nanowires composed of nanowhiskers, have been prepared in a controllable fashion by using a pore-wall modified alumina membrane and adjusting electrodeposition parameters. The mechanism of formation of the Co nanostructures was also discussed.     

Nanowire Array of Rare-Earth Simple Substance Neodymium by DC Electrodeposition with Barrier-Layer-Free Template

A two-step anodization method was adopted to prepare the porous anode alumina (PAA) template through the oxalic acid solution. By adjusting the parameters (such as current density, oxidation time, electrolyte concentration and other factors), the PAA template was obtained, which has the evenly distributed pores with similar diameters and hexagonal-shaped mouth. Meanwhile, by removing the barrier layer without peeling off the film, the residual aluminum becomes the base and acts as electrode. In the non-aqueous system, the nanowire of RE simple-substance (SS) Nd has been prepared with the template DC electrodeposition. The aperture diameter of PAA template is approximately 60 nm, and there is little change before and after the barrier layer is removed. The Nd nanowire given is orderly and in similar size. EDS shows that the nanowires contain simple-substance (SS) Nd and a tiny of Nd2O3, while the content of SS Nd is 92.73 wt%. Both the SS Nd and Nd2O3 nanowire are possessed of hexagonal structure     

High energy ion irradiation effect on light-emitting poly(3-methylthiophene) (P3MT) nanowires

Light-emitting poly(3-methylthiophene) (P3MT) nanowires with a diameter of ∼200 nm were fabricated using an electrochemical polymerization method based on an anodic alumina oxide (Al₂O₃) nanoporous template. The relatively high energy (3 MeV) Cl²⁺ ions were irradiated onto the P3MT nanowires with dosages from 1 × 10¹³ to 1 × 10¹⁵ ions/cm². To study the effect of high energy ion irradiation on P3MT nanowires, we measured UV/vis absorbance, Raman spectra, and laser confocal microscope photoluminescence (PL) on the nanometer scale. The relative atomic concentrations of carbon elements in the pristine and the 3 MeV Cl²⁺ ion-irradiated P3MT nanowires were investigated through XPS experiments. As the dosage of the 3 MeV Cl²⁺ ion irradiation increased, we observed that the P3MT nanowires changed to a partially carbonized form, and that the PL efficiency of the systems decreased.     

Effects of Atmosphere and Temperature on the Preparation of Tungsten Carbide via a One-Step Method

介绍了一种一步法制备碳化钨(WC)的新方法,以钨酸钠为原料,通过碳纳米管模板和载体制备小颗粒钨酸,制备出钨酸和碳黑的混合物作为反应前驱体,分别以H2和N2作为还原及保护气体合成WC,当合成温度高于800℃,反应前反应管内抽成真空,并在反应管内通入氢气和氮气流时,WO3首先被还原为W,接下来W被还原为W2C,最后,W2C被还原为最终产物WC。实验过程中通过调节气氛和温度2个重要反应条件,探索出了控制WC形貌及大量制备的方法,为WC的低成本及可控制备提供了新的途径。