A simple hydrothermal route to large-scale synthesis of uniform silver nanowires

This paper describes the preparation of uniform silver nanowires by reducing freshly prepared silver chloride with glucose at 180 degrees C for 18 hours in the absence of any surfactants or polymers. Scanning electron microscopy studies indicated that the silver nanowires are about 100 nm in diameter and up to 500 microm in length. High-resolution transmission electron microscopy analyses showed that the silver nanowires grow perpendicularly to the Ag(200) plane. The silver nanowires are believed to grow through a solid-solution-solid process. Some influential factors on the growth of silver nanowires are also discussed.     

Surfactant-free wet chemical synthesis of Co(OH)2 nanodisks and nanorings

In this paper, a facile, one-step hydrothermal method for synthesis of Co(OH)₂ nanodisks and nanorings without using any surfactants is reported. As-prepared samples were thoroughly characterized and analyzed by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), etc. The results showed that the size of as-prepared Co(OH)₂ nanodisks could be determined by controlling the concentration of NaOH (8?C16 mM) while maintaining other reaction conditions (such as temperature, reaction time, and solution compositions) unchanged. Furthermore, hexagonal nanorings could be obtained by changing the molar ratio between Ni and Co precursors.     

One-step template-free solution route for Cu(OH)<Subscript>2</Subscript> nanowires

Cu(OH)₂ nanowires with a diameter of 8–10 nm and lengths of tens of micrometers were fabricated in the basic solution by dropping simply NaOH solution into CuCl₂ solution at ambient temperature. The formation mechanism of nanowires was discussed. Scanning electron microscopy (SEM), transmission electron microscopy (TEM), and X-ray diffraction (XRD) were used to characterize the samples. This article was submitted by the authors in English.     

A simple large-scale synthesis of very long aligned silica nanowires

A simple method based on the thermal oxidation of Si wafers has been discovered to provide a large-scale synthesis of very long, aligned silica nanowires. The as-grown product was characterized by scanning electron microscopy, transmission electron microscopy, energy-dispersive X-ray spectroscopy, and photoluminescence. The obtained SiO₂ nanowires had no metal contaminations, ultralong lengths of millimeters, and most diameters of ∼50 nm. The PL spectra of the SiO₂ nanowires showed a strong and stable green emission at 540 nm. The nucleation and growth of the SiO₂ nanowires were investigated.     

A novel chemical route to SiO_2 nanowires

A white substance was got by directly heating TiSi powder on Ti foil, under Ar+O2 atmosphere. ED, EDX, SEM and HRTEM studies reveal that the white substance consists of amorphous SiO2nanowires of smooth surface and uniform diameter (40-90 nm). X-ray-induced luminescent emission experiment shows that two broad peaks are at 430 and 570 nm. A one-dimensional growth mechanism, on the basis of the one-dimensional thermal flow during nanowire formation, is discussed.     

A simple hydrothermal method for the large-scale synthesis of single-crystal potassium tungsten bronze nanowires

The large-scale synthesis of single-crystal K(x)WO(3) tungsten bronze nanowires has been successfully realized by a hydrothermal method under mild conditions. Uniform K(0.33)WO(3) nanowires with diameters of 5-25 nm and lengths of up to several micrometers are obtained. It is found that the morphology and crystallographic forms of the final products are strongly dependent on the sulfate and citric acid, which may act as structure-directing and soft-reducing agent, respectively. Some other influential factors on the growth of tungsten bronze nanowires, such as temperature and reaction time, are also discussed. It is worth noting that other alkali metal tungsten bronzes such as (NH(4))(x)WO(3), Rb(x)WO(3), and Cs(x)WO(3) could also be selectively synthesized by a similar route. Thus, this novel and efficient method could provide a potential mild route to selectively synthesize various tungsten bronze on-dimensional nanomaterials.     

A novel chemical route to SiO2 nanowires

A white substance was got by directly heating TiSi powder on Ti foil, under Ar+O ₂ atmosphere. ED, EDX, SEM and HRTEM studies reveal that the white substance consists of amorphous SiO ₂ nanowires of smooth surface and uniform diameter (40-90 nm). X-ray-induced luminescent emission experiment shows that two broad peaks are at 430 and 570 nm. A one-dimensional growth mechanism, on the basis of the one-dimensional thermal flow during nanowire formation, is discussed.     

A simple route to porous ZnO and ZnCdO nanowires

Porous ZnO nanowires were obtained in an inexpensive and simple way by thermally oxidizing ZnSe nanowires in air. The morphologies of the precursor and resulted nanowires are almost identical. X-ray diffraction and energy-dispersive X-ray spectroscopy reveal that the zinc blende ZnSe nanowires were transformed into wurtzite ZnO nanowires after oxidation. Transmission electron microscope measurements indicate that the ZnO nanowires are polycrystalline and are composed of nanoparticles and nanopores. ZnCdO nanowires, which were seldom reported previously, have also been prepared in this way. Just like the ZnO nanowires, the ZnCdO nanowires also show the porous structure. Photoluminescence studies on both ZnO and ZnCdO nanowires show intense near-band edge emissions at room temperature. The transition from one kind of nanowires to another by simple thermal oxidization described in this paper may be applicable to some other compound semiconductors and may open a practical route to yield nanowires.     

Shape-controlled synthesis of copper colloids with a simple chemical route

The new electrical and optical properties of nanomaterials depend sensitively on both size and shape, which are of both fundamental and technological interest. This paper introduces a simple chemical method to produce copper particles, which has the ability to shape the particle without using any capping agent or template. In our synthetic procedure, the reactant concentration and temperature exerted a strong influence on the shape of the copper particles. At low reactant concentrations, the particles were cubic; at high reactant concentrations, obtained particles were spherical. The number of hollow particles greatly increased when the synthesis was performed at low temperature. We also synthesized a copper cubic ring at lower temperature, and it has been rarely reported. The absorption spectrum of hollow particles showed obvious red shifts, which suggests the possible assembly of novel optical materials.     

Water-based wet chemical synthesis of (doped) ZnO nanostructures

Looking at its vast range of applications, nanostructured ZnO can be considered as a key technological material. Simple and ecological production techniques for this and other nanostructured materials can boost the detection of their unusual properties. In this context water-based wet chemical synthesis routes for nanostructured ZnO are explored in this study. The advantages and disadvantages of controlled double-jet precipitation, microemulsion preparation, hydrothermal synthesis and an aqueous solution-gel route are described for the formation of (doped) ZnO nanoparticles. The influence of the synthesis parameters on the particle size, size distribution and degree of agglomeration of the particles is reported. Thin films are prepared by chemical solution deposition from aqueous solution. The heat treatment profile and the precursor composition are seen to largely control the density, the grain size and the degree of preferential c-axis orientation.     

One-dimensional magnet basic copper(ii) dihydroxoborate Cu2{BO(OH)2}(OH)3: synthesis and properties

Russian Chemical Bulletin - Basic copper(ii) dihydroxoborate Cu2{BO(OH)2}(OH)3 contains infinite chains consisting of [CuO4] squares that are linked together by sharing opposite edges, due to which...     

A simple synthesis route and characterisation of Co(3)Mo(3)C

A simple, one-step thermal decomposition method for the preparation of Co(3)Mo(3)C is reported in this paper. In this novel synthesis route, a mixed-salt precursor, containing Co(CH(3)COO)(2) x 4H(2)O, (HMT)(2)(NH(4))(4)Mo(7)O(24) x 2H(2)O (HMT = hexamethylenetetramine), and excess HMT is directly decomposed to the bimetallic carbide under flowing argon at 1023 K. The role of HMT in the preparation process has been investigated and a detailed reaction mechanism is proposed based on the experimental results. The bimetallic carbide is characterised by X-ray diffraction, scanning electron microscopy, high-resolution transmission electron microscopy, BET surface area measurement and X-ray photoelectron spectroscopy. Furthermore, the activity of the as-prepared Co(3)Mo(3)C is evaluated by a 3-methylpyridine hydrodenitrogenation (HDN) reaction. The catalyst produced from this method provides better reactivity compared to the Co(3)Mo(3)C catalyst prepared by the conventional temperature-programmed reduction method.     

Room temperature electrodeposition of photoactive Cd(OH)2 nanowires

Cd(OH)₂ nanowires (NWs) were successfully prepared by room temperature electrogeneration of base using Cd(NO₃)₂ aqueous electrolyte and Anodic Alumina Membrane (AAM) as template. Cd(OH)₂ films have been also deposited on tin-doped indium oxide (ITO) for comparison. SEM analysis shows high quality deposits made of closely packed nanowires (NWs) into AAM and uniform flake-like surface on ITO. XRD analysis reveals that Cd(OH)₂ films on ITO are polycrystalline, while the nanowires grow along the preferential directions [1 0 0] and [1 1 0]. Photoelectrochemical measurements show that Cd(OH)₂ NWs are photoactive materials with indirect and direct band gap of 2.15 and 2.75 eV, respectively.     

Hydrothermal synthesis of ultralong and single-crystalline Cd(OH)2 nanowires using alkali salts as mineralizers

Ultralong and single-crystalline Cd(OH)(2) nanowires were fabricated by a hydrothermal method using alkali salts as mineralizers. The morphology and size of the final products strongly depend on the effects of the alkali salts (e.g., KCl, KNO(3), and K(2)SO(4) or NaCl, NaNO(3), and Na(2)SO(4)). When the salt is absent, only nanoparticles are observed in TEM images of the products. The 1D nanostructure growth method presented herein offers an excellent tool for the design of other advanced materials with anisotropic properties. In addition, the Cd(OH)(2) nanowires might act as a template or precursor that is potentially converted into 1D cadmium oxide through dehydration or into 1D nanostructures of other functional materials (e.g., CdS, CdSe).     

A simple and convenient route to prepare poly(vinylidene fluoride trifluoroethylene) copolymer nanowires and nanotubes

Poly(vinylidene fluoride trifluoroethylene) copolymer nanowires and nanotubes have been prepared for the first time via a high temperature (相似文献   

A new route for the fabrication of TiO2 ultrafiltration membranes with suspension derived from a wet chemical synthesis

Titania ultrafiltration membranes were successfully fabricated by a new route, which was directly derived from the nanoparticles suspension that was the intermediate product prior to dry and calcine in the synthesis of nanoparticle by a wet chemical method. The morphology and the crystal structure of the prepared membrane were analyzed by SEM and XRD. The effect of various dipping time on the membrane thickness was investigated. The rejection of the bovine serum albumin (BSA, 67,000 Da) was used to evaluate the separation characteristics of these membranes, and the relationship between the dipping time and the optimization thickness of the membrane was built on the base of the data of the pure water flux. SEM images showed that the surface of the membrane was defect-free and XRD revealed that the titania crystalline phase was pure anatase. The membrane thickness increased linearly with the square root of the dipping time and the dipping time of 30 s was necessary to form a defect-free titania layer on the top of supports. The titania layer derived from the dipping time of 30 s could be of thickness of 5.9 μm and an average pore size of 60 nm. The pure water permeability of the membrane was 860 × 10⁻⁵ L/(m² h Pa) (860 L/(m² h bar)), and the BSA rejections of the membranes prepared reached to 90% after 20 min running.     

Novel Janus Cu2(OH)2CO3/CuS microspheres prepared via a Pickering emulsion route

Janus Cu2(OH)2CO3/CuS microspheres were prepared via a Pickering emulsion route for the first time. By treating the Janus Cu2(OH)2CO3/CuS microspheres with dilute hydrochloric acid, ringent Cu2(OH)2CO3/CuS core/shell microspheres and ringent CuS shells were obtained. The hatch size of the ringent CuS shells increased with the increase of the hydrophobicity of the precursor Cu2(OH)2CO3 microspheres. Scanning electron microscopy, X-ray diffraction, energy dispersion spectra, and particle size analysis were used to characterize the products thus formed.     

A simple solution route to single-crystalline Sb2O3 nanowires with rectangular cross sections

We report a simple solution route to large-scale synthesis of uniform, single-crystalline, and well-faceted orthorhombic antimony trioxide (Sb(2)O(3)) nanowires with rectangular cross sections by direct air oxidation of bulk metal antimony (Sb) in a mixed solution made of ethylenediamine (EDA) and deionized water (DIW). The as-synthesized products were analyzed by range of methods, such as XRD, SEM, EDX, TEM, SAED, HRTEM, FTIR, Raman, UV-vis absorption, and photoluminescence (PL) spectra. The as-synthesized Sb(2)O(3) nanowires with rectangular cross sections are usually hundreds of micrometers in length, typically 80-100 nm in width, and 60-80 nm in thickness. The novel room temperature photoluminescence properties of Sb(2)O(3) nanowires with rectangular cross sections displayed a significant UV luminescence with a strong emission band at 374 nm, which was reported for the first time, indicating the as-synthesized products with an optical band gap E(g) = 3.3 eV. It is expected that as-synthesized Sb(2)O(3) nanowires would be a new member of functional materials and used in the manufacture of advanced nanodevices.     

Lithography inside Cu(OH)2 nanorods: a general route to controllable synthesis of the arrays of copper chalcogenide nanotubes with double walls

A series of well-aligned arrays of copper chalcogenide nanostructures, including Cu(7)S(4) and Cu(2-x)Se nanotubes with double walls have been successfully prepared by using Cu(OH)(2) nanorods as sacrificial templates. This new method is based on layer-by-layer chemical conversion and inward etching of the sacrificial templates, which is essentially a kind of lithography inside the Cu(OH)(2) nanorods. The key step of the process involves repeated formation of the copper chalcogenide wall and the dissolution of the Cu(OH)(2) core for two consecutive cycles. A large difference of the solubility product (Ksp) between the copper chalcogenide wall and the Cu(OH)(2) core materials is crucial for the direct replacement of one type of anions by the other. Our work provides a novel and general approach to the controllable synthesis of the arrays of copper chalcogenide nanotubes with double walls and complex hierarchies.     

New Cu(II) complexes based on the hydroxo-bridged dinuclear [Cu(OH)2Cu] units: step-like di- and trimerizations of [Cu(OH)2Cu] units

Four new Cu(II) complexes {[Cu(4)(bpy)(4)(OH)(4)(H(2)O)(2)]}(NO(3))(2)(C(7)H(5)O(2))(2)·6H(2)O 1, {[Cu(4)(bpy)(4)(OH)(4)(H(2)O)(2)]}(NO(3))(2)(C(5)H(6)O(4))·8H(2)O 2, {[Cu(4)(bpy)(4)(OH)(4)(H(2)O)(2)]}(C(5)H(6)O(4))(2)·16H(2)O 3 and {[Cu(6)(bpy)(6)(OH)(6)(H(2)O)(2)]}(C(8)H(7)O(2))(6)·12H(2)O 4 were synthesized (bpy = 2,2'-bipyridine, H(2)(C(5)H(6)O(4)) = glutaric acid, H(C(7)H(5)O(2)) = benzoic acid, H(C(8)H(7)O(2)) = phenyl acetic acid). The building units in 1-3 are the tetranuclear [Cu(4)(bpy)(4)(H(2)O)(2)(μ(2)-OH)(2)(μ(3)-OH)(2)](4+) complex cations, and in 4 the hexanuclear [Cu(6)(bpy)(6)(H(2)O)(2)(μ(2)-OH)(2)(μ(3)-OH)(4)](6+) complex cations, respectively. The tetra- and hexanuclear cluster cores [Cu(4)(μ(2)-OH)(2)(μ(3)-OH)(2)] and [Cu(6)(μ(2)-OH)(2)(μ(3)-OH)(4)] in the complex cations could be viewed as from step-like di- and trimerization of the well-known hydroxo-bridged dinuclear [Cu(2)(μ(2)-OH)(2)] entities via the out-of-plane Cu-O(H) bonds. The complex cations are supramolecularly assembled into (4,4) topological networks via intercationic ππ stacking interactions. The counteranions and lattice H(2)O molecules are sandwiched between the 2D cationic networks to form hydrogen-bonded networks in 1-3, while the phenyl acetate anions and the lattice H(2)O molecules generate 3D hydrogen-bonded anionic framework to interpenetrate with the (4,4) topological cationic networks with the hexanuclear complex cations in the channels. The ferromagnetic coupling between Cu(II) ions in the [Cu(4)(μ(2)-OH)(2)(μ(3)-OH)(2)] cores of 1-3 is significantly stronger via equatorial-equatorial OH(-) bridges than via equatorial-apical ones. The outer and the central [Cu(2)(OH)(2)] unit within the [Cu(6)(μ(2)-OH)(2)(μ(3)-OH)(4)] cluster cores in 4 exhibit weak ferromagnetic and antiferromagnetic interactions, respectively. Results about i.r. spectra, thermal and elemental analyses are presented.