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Abstract: Cubic phase silicon carbide (3C-SiC) nanowires (labeled as “Sample 1”) with diameters ranging from 10nm to 80nm and lengths up to several micrometers were obtained by using CHI3, Si powder, and metallic Na as reactants at 230°C. In addition, SiC polyhedra (labeled as “Sample 2”) with smooth surfaces and diameters of 2–5μm were obtained by using the different amounts of the same reactants at 500°C. The room-temperature photoluminescence (PL) spectra of Sample 1 and Sample 2 show strong ultraviolet emission peaks centered at 360nm and 354nm, respectively. Thermal gravimetric analysis (TGA) curves reveal that the thermal stability (against air oxidation) of Sample 2 is better than Sample 1. The possible formation mechanisms of the products with distinct dimensions were briefly discussed. [Copyright &y& Elsevier]

Abstract: Silicon carbide (3C-SiC) nanocrystals were prepared starting from SiO2, C2H5OH, and metallic Mg in an autoclave at 200°C. X-ray diffraction patterns of the sample can be indexed as the cubic phase of SiC with the lattice constant a =4.357Å, in good agreement with the reported value (JCPDS card no. 29-1129; a =4.359Å). Transmission electron microscopy images show that the product mainly composed of nanowires with diameters in the range of 10–30nm and lengths up to tens of micrometers; High-resolution transmission electron microscopy images reveal that these 3C-SiC nanowires grow along [111] direction; As polyvinylpyrrolidine was added into the above reactant system, the final products obtained at 180°C were mixed 3C and 2H-SiC flakes. Thermal gravimetric analysis curves reveal that these two samples have thermal stability below 800°C, and room-temperature photoluminescence spectrum of the 3C-SiC sample show a strong emission peak centered at 403nm. [Copyright &y& Elsevier]

Abstract: V2O3 and VN nanocrystals have been synthesized by the decomposition of the precursor NH4VO3 and following nitridation in an autoclave with metallic Na flux at 450–600°C. X-ray powder diffraction (XRD) recorded the evolution process of the reaction from precursor NH4VO3 to hexagonal V2O3 and then to NaCl-type VN. In addition, the products were characterized by X-ray photoelectron spectroscopy (XPS) and transmission electron microscopy (TEM). [Copyright &y& Elsevier]