Advanced Materials Research Vols. 881-883

Abstract: Gold nanoflowers were simply produced in aqueous solution containing peptides (NH₂-Leu-Aib-Trp-Ome) and sodium dodecyl benzene sulfonate. HAuCl₄ was reduced by peptides. Scanning electron microscopy and transmission electron microscopy images show flower-like nanoparticles were about 50-100 nm. X-ray diffraction and electron diffraction patterns suggest face-centred cubic structures for these gold branched nanoparticles. There are three main stages in the growth of the gold nanoparticles: nanocrystal, aggregated nanoparticle, and flower-like nanostructure. The performance of the gold nanoflowers when used for surface enhanced Raman scattering was explored using crystal violet as the probe, which indicates that the these gold nanoflowers are promising for use as excellent surface enhanced Raman scattering substrates.

Abstract: nanoTiO2 has many excellent properties, showing increasingly broad application prospects, the application of nanometer titanium dioxide research thus became one of the hot spot of research. Mainly in the field of chemical, water treatment field, environmental protection, electrode and nanoTiO2 solar cell areas, the application of the research were summarized, the shortage of the current in the research are pointed out, looks forward to the main research direction in the future.

Abstract: The raspberry-like gold nanoparticles were synthesized with high yields following reduction with hydrochloroauric acid and peptide (Boc-Leu-Aib-Trp-OH) in methanol solution. Peptide acted as reducing agent. The prepared raspberry-like gold nanoparticles are effective application for surface-enhanced Raman scattering in ascorbic acid (Vc). Here, we also demonstrate the effective catalysts of raspberry-like gold nanoparticles for the activation and reduction of methylene blue in the presence of NaBH₄.

Abstract: Engineered nanoparticles have been extensively used in electronics, energy, materials and biomedical areas. Engineered nanoparticles with unique magnetic, luminescent, and catalytic properties can not only benefit human society, but also cause potentially harmful interactions with living systems. This study was aimed at assessing the cytotoxicity of CuO ENPs, TiO₂ ENPs, CeO₂ ENPs, SWCNTs in human lung epithelial cell line (A549). Herein, we performed a comprehensive study on the cytotoxicity of four different ENPs by examining the viability of A549 cells. The results showed that CuO ENPs could cause a highest dose-dependent cytotoxicity, SWCNTs were more toxic than TiO₂ ENPs and CeO₂ ENPs to A549 cells, TiO₂ ENPs induced a slight loss of cell viability at 100 mg/L and CeO₂ ENPs had no obvious cytotoxicity. These effects were dose related, and should be considered in the application of different areas of ENPs.

Abstract: A new process was developed for synthesizing tungsten-doped vanadium dioxide VO₂(M) from ammonium metavanadate. The process includes obtaining V₂O₅ by pyrolysing NH₄VO₃, doping tungsten in V₂O₅ by sol-gel method, and reducing V₂O₅ to VO₂(M) with hydrazine by hydrothermal method. X-ray diffraction (XRD), scanning electron microscopy (SEM) and differential scanning calorimetry (DSC) were applied to characterizing the product. The experimental results indicated that tungsten doped VO₂ (M) nanoparticles were successfully synthesized. The product VO₂ (M) presents mainly rod-like and block-like morphology. The phase transition temperature decreases with tungsten doped amount increasing, the phase transition takes place over the range from 36.23°C to 62.16°C and the largest enthalpy of the phase transition is 16.24J/g.

Abstract: Two different BaTiO₃ (160nm) nanopowders coated with Y and with Dy were fabricated by an aqueous chemical coating method, and their dielectric properties and microstructures were investigated with X-ray diffraction, Impedance analyzer, SEM and TEM. Y and Dy were coated on the BaTiO₃ powder using nitrates. Coated BaTiO₃ powders were pressed in a disk shape and sintered at 1150~1200°C for 2 hours in reduced atmosphere of 10%H₂ - 90%N₂. Coating layer of the BaTiO₃ particle was thin with a thickness of 3 ~ 5nm. Coated BaTiO₃ sintered sample exhibited a larger lattice parameter (a, c) and smaller tetragonality (c/a) than pure BaTiO₃ one. Y coated BaTiO₃ sample sintered at 1200°C showed good dielectric properties with a high dielectric constant of around 2000 and a stable temperature coefficient of capacitance (TCC).

Abstract: Cu (OH)₂@TiO₂ nanowire arrays (NWAs) on the Fluorine-doped tin oxide (FTO) substrates had been fabricated via an simple and facile deposition method. The as-prepared Cu (OH)₂@TiO₂ NWAs were subsequently characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-Ray diffraction (XRD), UVVis diffuse reflectance spectra (DRS), X-ray photoelectron spectrometer (XPS) and photoelectrochemical measurements. This results suggested that the Cu (OH)₂@TiO₂ NWAs efficiently impeded the recombination between photoelectrons and holes. Therefore, this approach would afford a simple, effective, facile and low-cost method for preparation photoanode, which would enhance the hydrogen generating capability of TiO₂ from water splitting.

Abstract: With more and more extensive use of copper oxide nanoparticles ( CuO ENPs), potential risks have emerged to draw public attention. While toxicity data is still in lack of CuO ENPs to maize as the main agricultural crops in soil-cultivated. This research have reported the phytotoxicity of CuO ENPs at 0, 500, 1000 mg/kg concentration to maize (Zea mays L.) during different aging times from 0 d to 90 d in soil. CuO ENPs at 500 mg/kg presented more toxicity to maize than at 1000 mg/kg while growth inhibition decreased with the aging time.

Abstract: Nanomaterials are touching almost every aspect of modern life in recent years and attract the attention of scientists, becoming a hot research in a short time. The extensively use of engineered nanopaticles (ENPs) has increased the risk of ENPs entering into aquatic environments. This study outlines nanotoxicity on large aquatic plants which plays important role in aquatic system. A series of concentrations of copper oxide engineered nanoparticles (CuO ENPs) were used to test the nanotoxicity to aquatic plant Eichhornia crassipes. Results showed that inhibition of plant growth was significant after exposed to CuO ENPs at the concentration of 50 mg/L. the inhibition to the root lengh was obvious. The leaf epidermis was severely damaged. All the results showed that CuO ENPs had nanotoxicity to Eichhornia crassipes and the water system.

Abstract: In this work, the Fe-6.5wt%Si alloy cores with core-shell structures were prepared by Mechanical Alloying and Spark Plasma Sintering methods. The microstructure and magnetic properties of the samples were investigated with differential scanning calorimetry, X-ray diffraction, scanning electron microscopy and vibrating sample magnetometer. The results show that the synthesis of the Fe-6.5wt%Si powder with core-shell structures can be completion during mechanical alloying process. And the coreshell structure, Fe-6.5wt%Si as core and SiO₂ as shell, apparently exists in the sinter cores. The relative densities of sintered cores would ascend with increasing the sintering temperature. The Ms offered upgrade tendency with increasing the sintering temperature, while the Hc curves evolve with almost opposite phases. For the core sintered at 1050 °C, the following magnetic data were observed: Ms = 167.84 emu/g, Mr = 2.26 emu/g, Hc = 11.77 Oe, ρ = 2 μΩm and P15/400 = 2.47 W/kg.