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Three-dimensional hierarchical dendritic carbon structures with high densities of secondary carbon nanosheets have been fabricated using a solvothermal growth via reacting metal Na with tetrachloromethane in 200°C on Cu ribbon. Field-emission scanning electron microscopy and transmission electron microscopy images of the as-prepared sample shows that 3D hierarchical dendritic carbon structures are composed of carbon nanosheets with the thickness of about 20 nm. The powder X-ray diffraction and Raman spectra reveal the low graphitisation degree of the as-prepared sample. A possible formation mechanism has been proposed. [ABSTRACT FROM AUTHOR]

Abstract: Hollow CuO microspheres with diameters of 1–1.5 μm were synthesized on a large scale via a rational complexing-reagent assisted approach at low temperature, in which Cu(CH3COO)2⋅H2O served as copper source and (CH2)6N4 (HMTA) served as not only complexing reagent but also indirect soft template. The sample was characterized by XRD, FT-IR, TEM and FESEM. The effects of reaction temperature, solvent, and the ratio of HMTA/Cu(II) on the phase(s) of the resulting products were investigated. The possible formation mechanism of the hollow sphere-like CuO was also discussed. [Copyright &y& Elsevier]

Abstract: Rare-earth hexaborides (RB6, R=Ce, Pr, Nd) nanocrystals were prepared by a facile solid state reaction in an autoclave. Single-crystalline RB6 nanocubes were fabricated at 500°C starting from B2O3, RCl3·6H2O and Mg powder. RB6 nanoflakes and nanoparticles could be obtained around 400°C using NaBH4 as boron resource. XRD patterns show that all of the hexaborides are cubic phase with high crystallinity and high purity and have lattice parameters that are consistent with nearly stoichiometric products. Raman spectra elucidate the active vibrational modes of the hexaborides. The TEM and FESEM images clearly show that the nanocubes have an average size of 200nm and nanoparticles of 30nm. Our experiment developed an efficient, simple and low-cost route to prepare RB6, which could be extended further to the preparation of other rare-earth metal hexaborides. [Copyright &y& Elsevier]

Abstract: CuO shuttle-like nanocrystals were synthesized by the hydrolysis of cupric acetate (Cu(CH3COO)2·H2O) via a simple surfactant-assisted hydrothermal route at low temperature. It is found that the copper source, reaction temperature, reaction time, and surfactant cetyltrimethylammonium bromide (CTAB) are of importance to form the shuttle-like aggregates made by nanocrystals. A possible oriented-attachment mechanism for these aggregates is proposed based on their shape evolutions. [Copyright &y& Elsevier]

Abstract: Nanocrystalline ZrC has been prepared via a convenient route by the reaction of metallic magnesium powder with zirconium oxide and lithium carbonate in an autoclave at 600°C. X-ray powder diffraction pattern indicated that the product was cubic zirconium carbide, and the cell constant was a =4.693Å. Scanning electron microscopy (SEM) image showed particles with an average size of about 30nm. The product was also studied by thermogravimetric analysis (TGA). It had good oxidation resistance below 250°C in air. [Copyright &y& Elsevier]

Abstract: Nanocrystalline gallium nitride was synthesized by a solid-state reaction of metallic magnesium powder, gallium sesquioxide and sodium amide in a stainless steel autoclave at a relatively low temperature (400–550°C). The structures and morphologies of the obtained products were derived from X-ray powder diffraction (XRD) and transmission electron microscopy (TEM). XRD patterns indicated that the products were hexagonal GaN (JCPDS card no. 76-0703). The influence of reaction temperature on size of the products was studied by XRD and TEM. Furthermore, the thermal stability and oxidation resistance of the nanocrystalline GaN were also investigated. It had good thermal stability and oxidation resistance below 800°C in air. [Copyright &y& Elsevier]

Abstract: Niobium diboride (NbB2) nanorods have been successfully synthesized by the reaction of NbCl5 with NaBH4 in the temperature range of 550–650 °C in an autoclave. X-ray diffraction (XRD) and electron diffraction show that the as-prepared products are NbB2. Transmission electron micrographs shows that the average diameter of samples are in the range of 50–60 nm and the length is up to 600 nm. The mechanism for the formation of crystalline NbB2 is proposed. [Copyright &y& Elsevier]

Abstract: Nanocrystalline boron nitride (BN) was prepared by the reaction of BBr3 and Mg3N2 at 400 °C. X-ray powder diffraction (XRD) patterns can be indexed as hexagonal BN with the lattice constants of a=2.504 and c=6.671 Å. The transmission electron microscopy (TEM) images showed whisker-like and flake-like morphology. The product was also characterized by X-ray photoelectron spectrum (XPS) and Fourier transformation infrared spectroscopy (FTIR). [Copyright &y& Elsevier]