Advanced Materials Research Vol. 624

Abstract: A kind of SiO₂ hollow spheres with a layer of copper cladding have been prepared using the electroless copper plating metal processing technology on the surface of core material. We Study the effects of the process parameters on the properties of materials, and measure spectral reflectance for the SiO₂ hollow spheres with the surface modification. The results show that the reflectance is about 4% for the wavelength of 1.06μm and is about 0.44% for 10.6μm wavelength. This compound hollow sphere structures can be act as laser camouflage materials.

Abstract: The single-phase Υ-AlON powders were synthesized from three different precursors: Υ-Al₂O₃+C, Al(OH)₃+C, NH₄Al(OH)₂CO₃+C at 1750°C by carbothermal reduction and nitridation . The effects of aluminium source and synthetic process conditions on the characteristic of Υ-AlON powders were investigated in order to optimize the preparation method. It was revealed that the wet chemical processing was helpful to reduce partical size. The median particle sizes (d₅₀) of AlON powders synthesized from different precusors were 15.33 μm, 2.886 μm, 405.6 nm, respectively.

Abstract: In this paper, KMnO₄ was used as raw material, nano-MnO₂ with different morphologies such as flowers globular, hollow tubular and rodlike were obtained by the microwave assisted hydrothermal synthesis under the acidic condition. The crystal structure and morphology of the resultant MnO₂ were characterized by X-ray Diffraction (XRD) and Scanning Electron Microscope (SEM), respectively. The elements and content of samples were tested by Energy Dispersive Spectrometer (EDS). The influence of reaction temperature and holding time on crystal forms and morphologies of the MnO₂ was analyzed.

Abstract: In this work, nano-sized zinc molybdate (ZnMoO4) with several morphologies were prepared through introducing different template agents into hydrothermal system, in which ZnCl2 and Na2MoO4 were used as raw materials. Their structures and morphologies were characterized by XRD, FTIR and SEM techniques. Results showed that after constant temperature of 150°C for 4h, ZnMoO4 nanoparticles (~ 200 nm) were obtained in water medium. While in citric acid, CTAB and EDTA reaction templates, corresponding products were needle-like (400 nm *4000 nm), plate-like(350 nm*1500 nm*2000 nm) and microflower-like assembled by nanorods (300 nm*600 nm), respectively. All of them were monoclinic wolframite-type structure, and their photoluminescent (PL) spectra were also observed.

Abstract: In this work, water-soluble Fe₃O₄ nanopowder with mesoporous structure was prepared by the thermal decomposition of Fe-urea complex ([Fe(NH₂CONH₂)₆](NO₃)₃) in triethylene glycol (TEG), and the effects of reflux time and the concentration of precursor on the properties of Fe₃O₄ nanopowder were investigated. In addition, the adsorptive properties of the material were studied using Cr(VI) as a target pollutant. Prolonging reflux time and increase in concentration of [Fe(NH₂CONH₂)₆](NO₃)₃ in TEG can effectively improve the crystallinity and magnetic properties of the Fe₃O₄ nanopowder. The saturation magnetization (Ms) increases from 21.4 to 48.5 emu/g when the reflux time increases from 2 to 20 h. The maximum adsorption capacity of the Fe₃O₄ nanopowder for Cr(VI) is estimated to be 21.6 mg/g.

Abstract: In this paper, employing Cu(AC)2•H2O, SnCl2•2H2O and thiourea as raw materials, the composites of graphene/Cu2SnS3 quantum dots (QDs) were prepared simply and quickly using the hydrothermal method. Meanwhile, the separate Cu2SnS3 QDs were also synthesized in the same way. The as-obtained Cu2SnS3 QDs and composites’ phase structures were analyzed and characterized by powder X-ray diffraction (XRD), and the results indicated that the size of the Cu2SnS3 QDs in the composites were less than that of the separate Cu2SnS3 QDs. At the same time, their morphologies were also observed and cross-confirmed by Transmission Electron Microscopy (TEM), and the measurements manifested that Cu2SnS3 QDs were uniformly dispersed on the surface of the graphene, while the separate Cu2SnS3 QDs have obvious glomeration. In addition to this, elemental analysis was also made to verify the existence of Cu2SnS3 on the surface of graphene.

Abstract: Highly Ordered arrays of TiO₂ nanotubes on Ti wire were prepared by anodic oxidation with ethylene glycol solution of NH4F electrolyte. The phase compositions of the samples were characterized using X-ray diffraction (XRD) analysis using Cu-Kα radiation. The microstructure was observed using scanning electron microscopy (SEM). Experimental results show that at the anode condition of 95V, 50°C, and then themal treatment at 550°C, the highly ordered anatase TiO₂ nanotubes arrays arranged on the surface of Ti wire. The length of the nanotube achieved was about 31μm, the internal diameter and outer diameter of the nanotube was 127nm and 170nm, respectively.

Abstract: Nanowires of sodium titanate, TiO₂ and Eu³⁺/TiO₂ were synthesized by hydrothermal method, and their microstructure, optical properties and valence states of exterior elements were characterized by X-ray powder diffraction (XRD), scanning electron microscopy(SEM), X-ray photoelectron spectroscopy (XPS) and UV-Vis diffuse reflectance spectroscopy techniques. At the same time, the photocatalytic activities of the materials for degradation of methyl orange under visible-light irradiation were also investigated. The results showed the formation of nanowires of sodium titanate with average crystallite sizes of 50-200 nm and in lengths from several microns to several dozens microns, and its chemical formula was determined to be Na₂Ti₃O₇. TiO₂ and Eu³⁺ /TiO₂nanowires were prepared from the Na₂Ti₃O₇ nanowires via ion exchange (i.e., with H⁺ and Eu³⁺ ions) and high temperature sintering processes. These three kinds of nanowires showed different photocatalytic activities for degradation of methyl orange. Na₂Ti₃O₇ nanowire did not show any photocatalytic activity for methyl orange degradation, while TiO₂ nanowire was superior to Na₂Ti₃O₇ nanowire; and, Eu³⁺/ TiO₂ nanowire possessed the highest photocatalytic activity.

Abstract: In this work, plasma combined with maleic anhydride induced-graft polymerization method was employed to fabricate highly-functionalized carbon nanotubes, whose surface was coated by uniform polymaleic anhydride thin film. Their compositions and structures were characterized by FTIR, SEM and XPS techniques. In order to evaluate the modification effect, they were further used as modifier to improve the tensile and surface properties of fluorinated polyurethane elastomers.

Abstract: A novel solution-phase method is developed for preparation of amorphous carbon nanoparticles with high specific surface area under ambient atmosphere by the reaction of ferrocene and ammonium chloride in polyethylene glycol 400 (PEG 400) at 200 oC. Samples are characterized by X-ray diffraction (XRD), field-emission scanning electron microscopy (SEM), transmission electron microscopy (TEM) and N2 adsorption-desorption isotherms. It is found that the nanoparticles are complete amorphous and agglomerate together due to the strong surface tension. The amorphous carbon nanoparticles with a diameter of 40-100 nm have a wide size distribution of mesopores with a Brunauer-Emmett-Teller (BET) surface area of 402.28m2•g-1. It is proposed that the dissolved reactants uniformly dispersing in the solutions could react at a molecular level to form uniform carbon nanoparticles.