从无序到有序ZnO纳米棒的制备

采用3种不同的方法在氧化铟锡玻璃衬底上沉积一层ZnO纳米晶薄膜,然后采用改进的水热法在制备有ZnO纳米晶薄膜的衬底上生长ZnO纳米棒,实现了纳米棒从无序到有序的生长.从XRD和SEM图可得,有序的纳米棒沿(002)择优取向,基本与衬底垂直,平均直径约为40nm.     

脉冲激光沉积制备ZnO纳米棒的研究进展

综述了脉冲激光沉积法制备ZnO纳米棒的研究进展.介绍了不同制备参数条件下ZnO纳米棒的形貌特征、性质及其生长机理,阐述了利用脉冲激光沉积制备高质量ZnO纳米棒及阵列的条件,为ZnO纳米棒的制备及性质的深入研究提供了有益的参考.     

ZnO纳米棒的制备及其气敏性研究现状

ZnO是一种多功能金属氧化物半导体材料,由于ZnO纳米棒尺寸小,比表面积大,使得ZnO纳米棒制作成气体传感器,可以提高气敏传感器的灵敏度和响应速度,降低工作温度.综述了近年来ZnO纳米棒的制备方法,展望了其在气敏性方面的应用前景.     

ZnO纳米棒水热法制备及其发光性能

采用水热法在玻璃基底上成功制备出了ZnO纳米棒.用x射线衍射仪(xRD)和扫描电子显微镜(SEM)对ZnO纳米棒的晶体结构和表面形貌进行了表征,初步探讨了ZnO纳米棒的生长机理;同时对ZnO纳米棒的光致发光性能进行测量,分析了水热温度和反应时间对ZnO纳米棒光致发光性能的影响.结果表明:ZnO纳米棒呈现六方纤锌矿结构,具有沿(002)晶面择优生长特征;随着水热反应温度的升高,ZnO纳米棒的发光强度逐渐增强;随着反应时间的延长,ZnO纳米棒发光强度在1～3 h内增强,而在3～10 h反而减弱.     

ZnO纳米棒阵列、纳米片及其发光和光催化特性

首先通过溶胶-凝胶法在Si片基底上制备1层ZnO纳米薄膜,作为纳米棒的晶种层,然后利用金属浴沉积法在ZnO纳米薄膜基础上制备择优取向的ZnO纳米棒阵列,最后通过水热法二次成核结晶形成纳米片。研究证明,ZnO纳米棒阵列和纳米片均沿着c轴取向。在Cu2+抑制极性面生长的作用下,形成的ZnO纳米片结构均匀,分布面积广,单片ZnO纳米片的厚度约为8 nm,面积呈平方微米级,较大的有40μm2左右。ZnO纳米结构的生长取向对其物理化学性能具有重要影响。高度沿c轴取向的ZnO纳米棒有利于紫外光发射和激光器的发展,但极性面的缩小不利于光催化反应。     

热蒸发法ZnO纳米棒阵列的研究

采用热蒸发的方法在ZnO薄膜缓冲层上成功制备了高密度的ZnO纳米棒阵列，其中ZnO薄膜缓冲层是通过PLD（Pulsed Laser Deposition）的方法制得。与已有的报道不同，该方法未使用任何金属催化剂。X射线衍射仪（XRD）以及场发射扫描电子显微镜（FE-SEM）的结果表明，实验得到的ZnO纳米棒阵列整齐垂直排列在衬底上．此外，在常温下测量得到的光致发光（PL）谱和透射电子显微镜显示该ZnO纳米棒阵列结晶较好，无明显的缺陷,研究结果表明纳米棒阵列的形成主要归因于ZnO纳米棒和薄膜之间完美的晶格匹配。     

ZnO:Cd纳米棒的制备及其光催化降解性能研究

采用水热法制备了ZnO和不同Cd掺杂浓度的ZnO:Cd纳米棒。通过x射线衍射仪、扫描电子显微镜、紫外-可见-近红外分光光度计和拉曼光谱对ZnO:Cd纳米棒的结构和光学特性进行了系统研究。结果显示,样品为一维纳米棒结构,Cd的掺杂可以减小ZnO纳米棒的晶粒尺寸和光学带隙。利用分光光度计检测ZnO:Cd纳米棒对偶氮结构染料(甲基橙溶液)的光催化降解效率,结果表明Cd掺杂可以改善ZnO的光催化性能,掺杂浓度为16%时ZnO:Cd纳米棒对甲基橙溶液的光催化降解效率最高。     

纵向多孔及实心ZnO微纳米棒的制备、表征及其光催化性能研究

以硝酸锌和六次甲基四胺为原料,水为溶剂,采用低温水热法制备出具有优异光催化性能的六方纤锌矿结构ZnO微纳米棒,并研究了合成过程中磁力搅拌及原料溶液浓度对制备产物形貌及光催化性能的影响,建立了其光催化降解甲基橙的动力学方程。结果表明,搅拌条件下制备的产物为纵向多孔的棒状ZnO,无搅拌条件下制备的产物为实心ZnO纳米棒.优选出的硝酸锌和六次甲基四胺浓度均为0.025mol/L。相比于实心ZnO纳米棒,纵向多孔的棒状ZnO具有更优异的光催化性能,在紫外光照射20min后,对甲基橙的降解率达到100%。通过动力学模型拟合发现,纵向多孔的棒状ZnO具有更大的催化速率常数(0.2942 min~(-1)),是实心ZnO纳米棒催化速率常数(0.1306min~(-1))的2.25倍。     

纳米金属颗粒的湿化学制备

纳米金属颗粒在光电子、磁性材料和器件上具有表面增强Raman效应,量子点效应和高密度存储等重要特性.综述了在光电子、磁性材料和器件有着应用前景的金、银、铜、钴、镍、铋等金属纳米颗粒的湿化学制备,探讨了金属纳米颗粒湿化学制备控制颗粒大小、形状的一些因素和一般性特点,为制备颗粒大小、形状可控的其它种类的金属纳米颗粒作参考.     

电沉积法制备ZnO纳米棒/管阵列及其机理研究

采用恒电位电沉积法在未经修饰的ITO导电玻璃基底上用一步法制备了ZnO纳米棒阵列结构,并经碱蚀制备了ZnO纳米管阵列结构.通过阴极线性扫描分析了通氧及添加剂六次甲基四铵(HMT)对沉积ZnO薄膜的电化学行为的影响.结果表明,电沉积体系中通入氧气对阴极还原反应起到了加速作用,而电沉积体系中的HMT通过水解作用对电沉积反应起到了稳定剂作用.在氧气和HMT的协同作用下可使ZnO更加充分地成核生长,得到结构清晰分明的六方棱柱ZnO晶种,进而形成规则均一的ZnO薄膜.     

Investigation of ZnO nanorods synthesized by a solvothermal method, using Al-doped ZnO seed films

ZnO nanorods were successfully grown on common glass substrates using a simple solvothermal method via the precursors of zinc acetate dihydrate (Zn(CH₃COO)₂·2H₂O) and Hexamethylenetetramine (C₆H₁₂N₄) with equal molar concentration at 0.01 mol/l, 0.025 mol/l, 0.05 mol/l, and 0.075 mol/l. The ZnO nanorods were characterized by X-ray diffraction (XRD), Scanning electron microscopy, UV-Vis absorption spectrophotometer and photoluminescence (PL) spectrometer. XRD results indicated that all the ZnO nanorods were preferentially grown along [0 0 0 1] direction (c-axis). With an increase of Zn(CH₃COO)₂·2H₂O and C₆H₁₂N₄ concentration, the diffraction intensity of ZnO nanorod along c-axis also increased. Scanning electron microscopy images showed that the well-faceted hexagonal ZnO nanorods were grown vertically from the common glass substrates. In addition, with the increase of Zn(CH₃COO)₂·2H₂O and C₆H₁₂N₄ concentration, the exciton band of ZnO nanorods determined by UV-Vis absorption spectra gradually became narrow and the intensity of exciton band also remarkably augmented. Photoluminescence spectra showed that with the increase of Zn(CH₃COO)₂·2H₂O and C₆H₁₂N₄ concentration, the position of emission peak of ZnO nanorod blue-shifts towards shorter wavelength in UV region and the luminescence intensity remarkably enhances in visible emission range (470-630 nm).     

表面活性剂辅助低温固相合成CuS纳米棒

用表面活性剂聚乙二醇400为形貌控制剂,通过低温固相反应成功制备出CuS纳米棒.纳米棒的直径为10～60 nm、长度为100～600 nm.研究结果表明,在反应过程中,表面活性剂所形成的结构对最终纳米晶的形貌起着决定性的作用.用X射线粉末衍射和透射显微镜技术对所制备纳米晶的成分、形状和尺寸进行了表征分析.对CuS纳米棒的形成机理作了深入的讨论,提出了CuS纳米棒的表面活性剂软模板诱导自组装生长机理.     

A facile low-cost synthesis of ZnO nanorods via a solid-state reaction at low temperature

ZnO nanorods have been prepared via a solid-state reaction between anhydrous zinc sulfate and sodium hydroxide in the absence of surfactant and template at relatively low temperature. The products were characterized by XRD, XPS and TEM. The influence of Zn²⁺/OH⁻ ratio on the size and morphology of the as-prepared ZnO samples has been studied, and the experimental results showed that when Zn²⁺/OH⁻ ratio was 1:4, good rod-like morphology with the diameter of 30–50 nm and length of ca. 600 nm can be obtained. Finally, the mechanism for the ZnO nanorods developed in the reaction system has been explained.     

氧化锌陶瓷铌掺杂效应的低温导电特性研究

研究了Nb2O5掺杂的ZnO陶瓷在低温下导电特性。结果表明：低温状态下．随着Nb2O5掺杂量的增加,ZnO电阻率降低,不同温度下烧结的ZnO样品,烧结温度越高,电阻率愈小;同一烧结温度下,不同烧结时间的ZnO样品,随着烧结时间的增加,电阻率愈小。     

Growth of compact arrays of optical quality single crystalline ZnO nanorods by low temperature method

We report the synthesis and optical properties of compact and aligned ZnO nanorod arrays (dia, ∼ 50–200 nm) grown on a glass substrate with varying seed particle density. The suspension of ZnO nanoparticles (size, ∼ 15 nm) of various concentrations are used as seed layer for the growth of nanorod arrays via selfassembly of ZnO from solution. We studied the effect of various growth parameters (such as seeding density, microstructure of the seed layer) as well as the growth time on the growth and alignment of the nanorods. We find that the growth, areal density and alignment of the nanorods depend on the density of seed particles which can be controlled. It is observed that there is a critical density of the seed particles at which nanorod arrays show maximum preferred orientation along [002] direction. The minimum and maximum radius of the aligned nanorods synthesized by this method lie in the range 50–220 nm which depend on the seeding density and time of growth. These nanorods have a bandgap of 3.3 eV as in the case of bulk crystals and show emission in the UV region of the spectrum (∼ 400 nm) due to excitonic recombination and defect related emission in the visible region.     

低温陈化法制备ZnO微晶及其形貌控制

以氯化锌(ZnCl2)和氢氧化钠(NaOH)为原料,十二烷基硫酸钠(SDS)作添加剂,采用简单的低温陈化法在85℃合成出了多种形貌的ZnO微晶.应用X射线粉末衍射仪(XRD)、扫描电子显微镜(SEM)和高分辨透射电子显微镜(HRTEM)对产品进行表征.所得粉体均为六方晶系纤锌矿ZnO,其中3-D花状ZnO由多个沿c轴方向生长的1-D结构单晶(花瓣)组成.通过跟踪反应过程中Zn(Ⅱ)浓度的变化趋势,对不同形貌ZnO微晶的生长机理进行了初步探讨.结果表明,ZnO微晶的成核生长速率是其形貌的主要控制因素;同时,花状ZnO的性能指标还受成核数目和生长物源数量的影响.     

A new approach for synthesis of ZnO nanorod flowerets and subsequent pure free-standing ZnO nanorods

Present work reports the synthesis of ZnO flowerets consisting of nanorod petals of ZnO having a mean aspect ratio ～9, supported on micron sized Ni-enriched particles of size in the range of ～1–4?μm and also free-standing pure ZnO nanorods from mechanically alloyed Ni-Zn powder particles via selective leaching in NaOH solution. Optimization of the composition of the initial alloy powder, the concentration of NaOH and time of exposure in the solution was carried out to get to the ZnO flowerets with an increment in the surface area of the order of 400%. The mechanism and reaction chemistry of ZnO nanorods formation and growth were explained based on the evidence of various characterization techniques including inductive coupled plasma mass spectroscopy (ICP-MS) and electrochemical measurements. Free-standing pure ZnO nanorods were also synthesized by ultrasonically breaking the rod petals of ZnO from the base of the flowerets. Free-standing ZnO nanorods have a mean aspect ratio of 8.5?±?4, where the length and average diameter are ～356?±?64?nm and 42?±?16?nm, respectively, and the specific surface area of 12.5?m²?g^?1 with an increment of ～650% as compared to the mechanically alloyed powder particle.     

纳米ZnO低温脱除H2S工艺条件的研究

采用均匀沉淀法制备纳米ZnO,以其作为低温脱除H2S的活性组分,考察了纳米ZnO粒径、空速、反应温度、氧分压等因素对纳米ZnO脱硫性能的影响,并对脱硫剂的结构进行了表征.结果表明:在常压、低温、氧分压较低的条件下,粒径越小脱硫性能越强,260℃焙烧制得的纳米ZnO脱硫剂具有高的脱硫活性,H2S可选择性地被氧化为单质S,转化率高达100%,脱硫活性时间是分析纯ZnO的40倍.尾气中未见SO2产生.     

Preparation of nanostructured ZnO nanorods in a hydrothermal-electrochemical process

An array of ZnO nanorods, each nanorod being covered with a shell of porous ZnO was prepared in two steps by hydrothermal-electrochemical processes. The growth of ZnO nanorods was achieved in a zinc nitrate and hexamethylenetetramine aqueous solution on fluorine-doped tin oxide film. The porous ZnO shell was grown from a similar solution in the presence of eosin Y as nanostructuring agent. A dye-sensitized solar cell was assembled using as photoanode an eosin Y sensitized ZnO nanorod/shell layer.