Hydrothermal synthesis of one-dimensional (1D) Na<Subscript>x</Subscript>TiO<Subscript>2</Subscript> nanostructures

Nanorods of sodium titanium dioxide bronze Na_xTiO₂ were synthesized by the hydrothermal treatment of the amorphous TiO₂·nH₂O gel with 10 M NaOH followed by ultrasonication in 0.1 M HCl and thermal treatment (500°C, 10 h). The thermal treatment of the nanorods does not change the morphology of the particles. According to the electron diffraction data, the Na_xTiO₂ nanorods grow along the c axis.__________Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 1, pp. 71–73, January, 2005.     

水热法制备Sb2S3纳米棒有序阵列

以Sb(S₂CNEt₂)₃为单源前驱体，通过改变时间、温度、表面活性剂等反应条件，用水热法成功合成了各种尺寸的Sb₂S₃纳米棒及其有序阵列。X-射线衍射(XRD)、能量分散光谱(EDS)以及选区电子衍射(SAED)研究表明纳米棒由正交晶系Sb₂S₃单晶构成。扫描电子显微镜(SEM)和透射电子显微镜(TEM)研究显示Sb₂S     

Two-step synthesis of high aspect ratio gold nanorods

We describe a very simple, two-step synthetic method to prepare gold nanorods with extremely high aspect ratios (> 20) and average lengths of more than 1000 nm. The method is based on a seed-mediated growth in presence of the surfactant cetyltrimethylammonium bromide. The length and aspect ratios of the nanorods can be manipulated by varying the surfactant concentration.     

Selective synthesis and characterization of single-crystal silver molybdate/tungstate nanowires by a hydrothermal process

Selective synthesis of uniform single crystalline silver molybdate/tungstate nanorods/nanowires in large scale can be easily realized by a facile hydrothermal recrystallization technique. The synthesis is strongly dependent on the pH conditions, temperature, and reaction time. The phase transformation was examined in details. Pure Ag(2)MoO(4) and Ag(6)Mo(10)O(33) can be easily obtained under neutral condition and pH 2, respectively, whereas other mixed phases of Mo(17)O(47), Ag(2)Mo(2)O(7,) Ag(6)Mo(10)O(33) were observed under different pH conditions. Ag(6)Mo(10)O(33) nanowires with uniform diameter 50-60 nm and length up to several hundred micrometers were synthesized in large scale for the first time at 140 degrees C. The melting point of Ag(6)Mo(10)O(33) nanowires were found to be about 238 degrees C. Similarly, Ag(2)WO(4), and Ag(2)W(2)O(7) nanorods/nanowires can be selectively synthesized by controlling pH value. The results demonstrated that this route could be a potential mild way to selectively synthesize various molybdate nanowires with various phases in large scale.     

水/油型微乳液中球形及棒状钛酸锶钡纳米粒子的控制合成

Barium strontium titanate nanoparticles with spherical and rod-like morphologies were synthesized in water/Triton X-100/n-hexanol/cyclohexane quaternary reverse microemulsion solution. The influences of the molar ratio of water to surfactant (ω₀) and the concentration of reactants on the morphology and size of barium strontium titanate nanoparticles were studied. The structure, compositions and morphology of the prepared products were characterized by XRD, SAED, ICP, EDS and TEM. The results show that the obtained Ba_0.7Sr_0.3TiO₃ spherical nanoparticles with diameters of 20～100 nm and the Ba_0.7Sr_0.3TiO₃ nanorods with diameters of 70～120 nm and lengths up to 600～800 nm are a single crystal, with a cubic phase. The molar ratio for barium, strontium and titanate in products is about 0.7:0.3:1.     

球磨-溶剂热诱导法合成WS2纳米棒及其摩擦性能

采用行星式高能球磨机，将WS₂与S粉末混合球磨，得到纳米片状结构的前驱体，然后添加分散剂聚乙二醇(PEG)用溶剂热诱导的方法使纳米片状前驱体发生结构转变，制备了棒状结构的WS₂纳米材料。用XRD、SEM、TEM等方法对WS₂纳米棒进行了形貌和结构表征，并对其作为润滑油添加剂的摩擦性能进行了初步的研究。     

Hydrothermal Synthesis and Optical Properties of ZnO Nanostructured Films Directly Grown from/on Zinc Substrates

Uniform ZnO nanorods arrays are grown directly from and on Zn foils in pure water under hydrothermal conditions at a relatively low temperature. The nanorods are 80–200 nm in diameter and ∼ 1 μm in length, which grow on the Zn foil along the [001] direction. By changing the pure water to a urea solution, a Zn compound ([Zn₅(OH)₆(CO₃)₂], a precursor of ZnO nanoflowers film, is created by self-assembly. The ZnO nanoflowers film can be easily obtained by heating the [Zn₅(OH)₆(CO₃)₂] compound in N₂ at 350∘C for 5–6 hours. Possible growth processes of the ZnO nanorods arrays and the [Zn₅(OH)₆(CO₃)₂] nanoflowers are discussed. Photoluminescence properties of the as-prepared ZnO nanostructures have been measured. The ZnO nanorods array synthesized using our method has minimal defects so that only band-gap emission is observed. However, the ZnO nanoflowers film, obtained by heating the [Zn₅(OH)₆(CO₃)₂] nanoflower precursor in N₂, is polycrystalline and displays strong defect-related emission.     

CdS nanocrystallites sensitized ZnO nanorods with plasmon enhanced photoelectrochemical performance

A sandwiched structure of CdS/Ag/ZnO nanorod photoanode exhibits greatly enhanced photoelectrochemical activity for solar hydrogen generation, due to synergistic effect of CdS nanocrystallites and plasmonic Ag nanoparticles for the enhanced optical absorption and the promoted charge carrier separation.     

Nanorods of Various Oxides and Hierarchically Structured Mesoporous Silica by Sol-Gel Electrophoresis

In this paper, we report the template-based growth of nanorods of oxides and hierarchically structured mesoporous silica, formed by means of a combination of sol-gel processing and electrophoretic deposition. Both single metal oxides (TiO₂) and complex oxides (Pb(Zr_0.52Ti_0.48)O₃) have been grown by this method. This method has also been applied to the growth of nanorods of mesoporous silica having an ordered pore structure, where the pores are aligned parallel to the long axis of the nanorod. Uniformly sized nanorods of about 125–200 nm in diameter and 10 m in length were grown over large areas with near unidirectional alignment. Appropriate sol preparation yielded the desired stoichiometric chemical composition and crystal structure of the oxide nanorods, with a heat treatment (500–700°C for 15–30 min) for crystallization, densification and any necessary pyrolysis.