Facile one-step synthesis of Cu2O@Cu sub-microspheres composites as anode materials for lithium ion batteries

Cu_2O@Cu sub-microspheres composites with a narrow particle size distribution from 300 to 500 nm was successfully fabricated by one-step synthesis through the direct thermal decomposition of copper nitrate(Cu(NO_3)_2) in octadecylamine(ODA) solvent. As anode materials for lithium ion batteries, the Cu_2 O@Cu composites obviously possess high specific capacity, excellent cyclic stability and rate capability. The coulombic efficiency is about 84% in the 1 st cycle and increases significantly up to 97.8% during successive cycles at various current densities. Even under a high current density of 500 m A g~(-1), the discharge capacity of Cu_2 O@Cu composites remains up to 200 m Ah g~(-1). The excellent electrochemical properties are ascribed to the synergistic effect between high electronic conductivity and volume-buffering capacity of metallic copper composited with Cu_2 O.     

A Novel one-step synthesis of Ag-doped ZnO nanoparticles for high performance photo-catalytic applications

In this report, pure and silver (Ag) doped zinc oxide (ZnO) nanoparticles with various concentrations of silver (5 and 10 wt%) was successfully synthesized by a novel and one step microwave irradiation method. Powder X-ray diffraction results indicates that all of the as-synthesized samples including the highest Ag (10 wt%) doping have a hexagonal wurtzite type structure and average crystalline size was found to be 28, 21 and 16 nm for pure and Ag doped ZnO respectively. Spherical shaped morphology with an average diameter of around 32–13 nm was observed by Transmission electron microscope analysis. UV–Vis spectra revealed that, Ag doped samples exhibits a red shift in the absorption band edge with increasing Ag dopant concentration. The photocatalytic degradation of methyl violet (MV), phenol and rhodamine B (RHB) was investigated by using Ag-ZnO catalyst under UV light irradiation. The result showed that the photocatalytic property was significantly improved by Ag doping. The improved photocatalytic mechanism by Ag doping was also discussed. The samples were further characterized by photoluminescence spectra and Fourier Transform Infrared Spectra (FTIR) analysis.     

Potato extract as reducing agent and stabiliser in a facile green one-step synthesis of ZnO nanoparticles

A facile green recipe was developed to synthesise highly pure, safe and durable zinc oxide nanoparticles (ZnO Nps) using homemade starch-rich potato extract. The ZnO Nps were synthesised using zinc nitrate and potato extract, and the whole reaction is carried out for 30 min at 80 °C. In the synthesis, starch-rich potato extract acted as the reducing agent and as a stabilising layer on freshly formed ZnO Nps. Hexagonal (wurtzite) shaped ZnO Nps with size about 20 ± 1.2 nm were synthesised and characterised using X-ray diffraction, transition electron microscope and scanning microscopy analyses. Fourier transform infrared spectral analysis indicated that highly pure ZnO nanopowders were obtained at higher temperatures. The use of environmentally benign and renewable material as the respective reducing and protecting agents, starch-rich potato extract, as well as a gentle solvent medium (H₂O), offered a simple and quite efficient procedure for the synthesis of ZnO Nps in neutral medium with promising potential for biological and biomedical applications.     

A simple microwave-assisted decomposing route for synthesis of ZnO nanorods in the presence of PEG400

In the paper, a simple microwave-assisted decomposing reaction in the presence of PEG400 has been successfully developed to synthesize ZnO nanorods with 10-25 nm of diameter and 60-200 nm of length. The product was analyzed and characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and HRTEM. Ultraviolet-visible (UV-vis) absorption peak of ZnO nanorods shows a distinct blue shift from that of the bulk and the Photoluminescence (PL) spectrum exhibits a strong near-band-edge emission at 385 nm. Further experiments have also been designed, and the results show that microwave radiation and surfactant PEG400 all played an important role on the formation of ZnO nanorods.     

A simple one-step solvothermal synthesis of hierarchically structured ZnO hollow spheres for enhanced selective ethanol sensing properties

A simple one-step solvothermal method, using ethanolamine as solvent without any additives except zinc source, has been employed to synthesize hierarchically structured ZnO hollow spheres consisting of numerous orderly and radical nanorods with diameter of several tens nanometers and length of 2–3 μm. The ethanolamine and the solvothermal process play the critical role in the synthesis of the ZnO hollow spheres by the primary formation of ZnO crystal nucleus and subsequent transformation into nanorods, which self-assemble into hollow spheres. The morphology and structure of the spheres have been characterized by transmission electron microscopy, field emission scanning electron microscopy, X-ray powder diffraction, high-resolution transmission electron microscopy, and Brunauer–Emmett–Teller N₂ adsorption–desorption analyses. The results also indicate that the sensor based on the prepared ZnO hollow spheres exhibit good ethanol sensing performance, which can be attributed to its structural defects and high surface-to-volume ratio that significantly facilitate the absorption of oxygen species and diffusion of target gas. Besides, the sensor shows high selectivity to ethanol because ZnO as a basic oxide is favored for dehydrogenation of ethanol.     

Fast synthesis of nanostructured ZnO particles from an ionic liquid precursor tetrabutylammonium hydroxide

Microwave irradiation could allow a more efficient and homogeneous heating of the reaction mixture to result in a fast synthesis. We propose a facile route for the synthesis of ZnO particles from an ionic liquid precursor with the assistance of microwave heating in which the ionic liquid has multifunctions (adsorbing microwave and acting as solvent, reactant, template) in the particle formation process. It demonstrates that ZnO particles with uniform size and morphology could be synthesized from tetrabutylammonium hydroxide ionic liquid precursor by the microwave heating method. Room temperature photoluminescence spectroscopy is measured to reveal the optical property of the as-obtained products. Moreover, the photocatalytic activity of the synthesized ZnO particles for the degradation of Rhodamine B is investigated.     

Cross-linking regulators in one-step synthesis of macronet ion-exchangers

Hydrophillic macronet resins were prepared via a route which includes simultaneous sulphonation and cross-linking of styrene-acrylonitrile copolymer and polystyrene foam. Chlorosulphonic acid was employed as both the sulphonating reagent for the introduction of the sulphonic acid group on styrene units and the medium for the formation of sulphone-type cross-links. Controlled cross-linked structures were achieved by the parallel participation of acetic acid or acetic anhydride as sulphone cross-bridging regulators. The reaction yield, as well as the properties of the formed gels, were studied in respect to the cross-linking regulator concentration and the chlorosulphonic acid flow rate. Both strongly and weakly acidic ion-exchangers on the same substrate were achieved when styrene-acrylonitrile copolymer was used as a raw material. The synthesized macronet ion-exchangers were found to exhibit high swelling abilities and intermediate ion-exchange capacities while scanning electron microscopy (SEM) revealed their morphology.     

A one-step method to fabricate lotus leaves-like ZnO film

Superhydrophobic surface is commonly fabricated by a combination of micro- and nano-scale structure and low surface energy materials. In this paper we fabricated a lotus leaves-like ZnO nano-forest surface by alkaline hydrothermal method, and the formation of micro- and nano-scale structured surface is controlled by the growth of the ZnO nanoseed layer. The growing ZnO nano-forest exhibits a perfect superhydrophilicity with a low water droplet CA about 1°. After modification with Teflon AF, the surface exhibits a superhydrophobicity with a water CA above 170°. The method is simply controllable, cost-effective, and has a wide range of potential applications such as self-cleaning superhydrophobic coating on large areas of different substrates.     

模板法制备氧化锌片状晶体

介绍一种制备在001轴方向高度取向生长的纳米片状氧化锌(ZnO)晶体的方法.在一定量的模板剂PEG600存在下,用氢氧化钠溶液调节硫酸锌溶液至一定pH值制得溶胶,然后在180℃下处理此溶胶7h,即可得结晶形态完好的纳米六方片状ZnO.同时讨论了低温近中性水溶液中ZnO晶体在有模板剂存在下的生长习性.     

Templated one-step synthesis of compositionally encoded nanowire tags

Multimetal nanowire tags, with distinct encoding patterns, have been prepared using a one-step templated electrodeposition from solutions containing different concentrations of various metal ions. Such synthesis of compositionally encoded nanowire tags is substantially faster and simpler than the preparation of striped nanowires based on sequential plating steps from different metal solutions and leads to high identification accuracy. The alloy nanowire preparation route leads to a high coding capacity with a large number of distinguishable voltammetric signatures, reflecting the predetermined composition of the metal mixture plating solution (and hence the nanowire composition). Factors influencing the identification accuracy are evaluated using three-metal (In, Pb, Bi) alloy nanowires, and the relative advantages and disadvantages of the new route are discussed.     

Properties of PEDOT:PEG/ZnO/p-Si heterojunction diode

The zinc oxide (ZnO) and poly(3,4-ethylenedioxythiophene) bis-poly(ethyleneglycol) (PEDOT:PEG) films were deposited on p-Si substrate by sputter and spin coating methods, respectively. An organic/inorganic heterojunction diode having PEDOT:PEG/ZnO on p-Si substrate was fabricated. The barrier height (BH) and the ideality factor values for the device were found to be 0.82 ± 0.01 eV and 1.9 ± 0.01, respectively. It has been seen that the value of BH is significantly larger than those of conventional Au/p-Si metal–semiconductor contacts. The PEDOT:PEG/ZnO/p-Si heterostructure exhibits a non-ideal I–V behavior with the ideality factor greater than unity that could be ascribed to the interfacial layer, interface states and series resistance. The modified Norde's function combined with conventional forward I–V method was used to extract the parameters including the barrier height and series resistance. At the same time, the physical properties of ZnO and PEDOT:PEG films deposited by sputter and spin coating technique, respectively, were investigated at room temperature. The obtained results indicate that the electrical parameters of the diode are affected by structural properties of ZnO film and PEDOT:PEG organic film.     

Functions of surfactants in the one-step synthesis of surfactant-intercalated LDHs

Surfactant-intercalated Zn and Al layered double hydroxides (ZnAl-LDHs) were synthesized via spontaneous self-assembly of the surfactants (sodium dodecyl sulfate and sodium dodecyl benzene sulfonate) and the LDH salt precursors. To understand the function of the surfactants in the synthesis, the surfactant-modified ZnAl-LDHs and their intermediates before aging were characterized via X-ray diffraction, Fourier transform infrared spectroscopy, Field emission scanning electron microscopy, and thermogravimetric analysis. In addition, fluorescence spectroscopy was used to in situ trace the microenvironmental variations of the reactants in the synthesis. It was found that the anionic surfactants can interact with the LDH precursors to form cooperative micellar assemblies, which increase the concentration of cationic counter ions around the micelles leading to enhanced growth of the LDH sheets along their lamellar surface direction and the stacking of LDH sheets into nanoparticles as the surfactant possesses longer molecular length. Because of the hydrophobicity of the intermediate sheets coated with surfactants, the reaction between the dissolved CO₃ ^2? and the LDH intermediate sheets can be greatly reduced, and thus no strict N₂ protection was necessary in this method. This mechanistic understanding of the effects of the surfactants on the formation of LDHs is critical in successful synthesis of organic-intercalated LDHs in complicated system by void the interruption of competitive ions.     

聚乙二醇辅助电沉积ZnO纳米棒阵列的研究

以聚乙二醇（PEG-400）为添加剂,采用恒电位方法直接在ITO导电玻璃上制备了ZnO纳米棒阵列膜,用扫描电子显微镜（SEM）、X射线衍射仪（XRD）等分析手段对ZnO纳米棒阵列的形貌和结构进行了表征。结果表明所得ZnO纳米棒为六方纤锌矿型单晶结构,沿着垂直于基底的c轴极性生长,呈现出均匀的六方棒状形貌;在电沉积初期,PEG-400通过其大分子链的空间位阻作用及包覆作用对ZnO成核粒子的形貌和分散性产生显著影响,进而可以有效调整进一步生长所得ZnO纳米棒阵列的密度和垂直度,当PEG-400在电沉积液中的体积分数为2%时,可以得到取向良好垂直度高的纳米棒阵列;光电性能测试表明,ZnO纳米棒阵列膜电极的光电流随着阵列规整度提高而增大。     

Microfluidic one-step synthesis of alginate microspheres immobilized with antibodies

Micrometre- and submicrometre-size functionalized beads are frequently used to capture targets of interest from a biological sample for biological characterizations and disease diagnosis. The main challenge of the microbead-based assay is in the immobilization of probe molecules onto the microbead surfaces. In this paper, we report a versatile droplet microfluidics method to fabricate alginate microspheres while simultaneously immobilizing anti-Mycobacterium tuberculosis complex IgY and anti-Escherichia coli IgG antibodies primarily on the porous alginate carriers for specific binding and binding affinity tests. The binding affinity of antibodies is directly measured by fluorescence intensity of stained target bacteria on the microspheres. We demonstrate that the functionalized alginate microspheres yield specificity comparable with an enzyme-linked immunosorbent assay. The high surface area-to-volume ratio of the functionalized porous alginate microspheres improves the detection limit. By using the droplet microfluidics, we can easily modify the size and shape of alginate microspheres, and increase the concentration of functionalized alginate microspheres to further enhance binding kinetics and enable multiplexing.     

Template-directed one-step synthesis of flowerlike porous carbonated hydroxyapatite spheres

Flowerlike porous carbonated hydroxyapatite (CHAp) spheres were first synthesized by the template-directed self-assembly method in a high-pressure system. The product was characterized via Fourier transform infrared (FT-IR), X-ray diffraction (XRD) and scanning electron microscopy (SEM). The results showed that flowerlike porous CHAp spheres were obtained, that the average granularity of porous CHAp spheres is about 20 μm, that the average aperture is about 1 μm, and that the average thickness of flakes is about 50 nm. Great amounts of OH channels, high special surface area and regular spherical shape imply potential applications.     

Solvothermal synthesis of nanorods of ZnO, N-doped ZnO and CdO

ZnO nanorods with diameters in the 80-800 nm range are readily synthesized by the reaction of zinc acetate, ethanol and ethylenediamine under solvothermal conditions. The best products are obtained at 330 °C with a slow heating rate. Addition of the surfactant Triton^®-X 100 gave nanorods of uniform (300 nm) diameter. By adding a small amount of liquid NH₃ to the reaction mixture, N-doped ZnO nanorods, with distinct spectroscopic features are obtained. CdO nanorods of 80 nm diameter have been prepared under solvothermal conditions using a mixture of cadmium cupferronate, ethylenediamine and ethanol at 330 °C. Similarly, Zn_1−xCd_xO nanorods of a 70 nm diameter are obtained under solvothermal conditions starting with a mixture of zinc acetate, cadmium cupferronate, ethanol and ethylenediamine.     

Rapid synthesis of flower-like ZnO nanostructures

Flower-like ZnO nanostructures were prepared via microwave assisted heating in the presence and absence of ionic liquid (IL). X-ray diffraction analysis (XRD), Scanning electron microscopy SEM and room temperature photoluminescence (PL) spectra have been employed for characterization of the products. The SEM image illustrates the surface of flower-like ZnO prepared in the presence of IL is not smooth and consists of nanoparticles with grain size of about 48 nm. PL spectra of flower-like ZnO in absence and presence IL reveal similar photoluminescence features: a strong UV, weak blue and green-yellow emissions peak at a bout 393 nm, 448 nm and 583 nm respectively. The strong UV photoluminescence and the weak green emission indicate the good crystallization quality of the flower-like nanostructure. The results show that imidazolium-based IL can be used as template for achieving very high level control over the size and shape of nanostructures. The approach developed in this work can potentially be used as a viable method for making various other uniform nanostructures in the presence of IL. This method is simple, fast, low-cost and suitable for large-scale production of ZnO nanostructures.     

Hydrothermal synthesis of phosphate-mediated ZnO nanosheets

ZnO nanosheets were obtained via a simple hydrothermal synthesis in the presence of sodium tripolyphosphate. The formation mechanism and effect of sodium tripolyphosphate concentration on the morphology of ZnO nanosheets have also been reported. Field emission scanning electron microscopy, transmission electron microscopy and fourier transform infrared spectroscopy were used to characterize the structure features and chemical compositions. The results show that the replacement of OH^? dangling bond on ZnO positive polar faces (0001) by PO₄^3? hinders splicing growth of [Zn(OH)₄]^2? growth units along the [0001] direction, which results in the formation of ZnO nanosheets.     

Vapor phase synthesis of ZnO structures

We observed zinc oxide structures formed in an oxygen-containing atmosphere as a result of oxidation of the surface of zinc droplets. The gas-phase oxidation leads to the formation of hollow ZnO whiskers on the metal surface, which grow due to the transport of zinc vapor through their channels. It was found that high partial pressures of zinc and atomic oxygen give rise to fractal structures, which appear in a cascade process involving the sequential formation of zinc oxide vapor, ZnO clusters, and cluster aggregates as a result of the cluster-cluster interaction. A deposit of ZnO synthesized on the cathode surface exhibits a columnar structure.     

Hydrothermal synthesis of hexagonal ZnO clusters

Hydrothermal process was applied to synthesize zinc oxide nanocrystals. X-ray powder diffraction and scanning electron microscopy were used to analyze the crystal structure and surface morphology. XRD pattern analysis showed that the ZnO clusters are single hexagonal phase of wurtzite structure (space group P63 mc) with no impurity of Zn and Zn(OH)₂. Also, SEM images revealed that the size of a single ZnO crystal is between 200-500 nm in diameter and 2-5 μm in length. The influence of potassium iodide (KI) as a surfactant on the crystallinity of ZnO has been investigated.