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Abstract: W/WS2 inorganic fullerene-like (IF) nanoparticles with core–shell structure are synthesized by the reaction of tungsten nanospheres and sulfur at relatively low temperatures (380–600°C) under hydrogen atmosphere, in which tungsten nanospheres were prepared by wire electrical explosion method. Images of transmission electron microscopy and high-resolution transmission electron microscopy show that the composite particles are of core–shell structure with spherical shape and the shell thickness is about 10nm. X-ray powder diffraction results indicate that the interlayer spacing of IF-WS2 shell decreases and approaches that of 2H-WS2 with increasing annealing temperatures, representing an expansion of 3.3–1.6%. A mechanism of IF-WS2 formation via sulfur diffusion into fullerene nanoparticles is discussed. Thermal analysis shows that the nanoparticles obtained at different temperatures exhibit similar thermal stability and the onset temperature of oxidization is about 410°C. Encapsulating hard tungsten core into IF-WS2 and the spherical shape of the core–shell structures may enhance their performance in tribological applications. [Copyright &y& Elsevier]

Abstract: A novel core–shell structure material, Cu–Zn/ZnO, was prepared by a surface modification precipitation process in aqueous solution at low temperature. A nucleation and crystal growth model for this structure was proposed. The resultant nanocomposites were characterized by X-ray diffraction, transmission electron microscope, field emission scanning electron microscope and photoluminescence spectroscope. Results showed that 20–50nm thick ZnO shell was obtained on the surface of Cu–Zn nanopowders directly in the aqueous solution at 40°C during the precipitation process and as-synthesized materials have a strong ultraviolet luminescence peak around 379–390nm, but no usual defect-related emissions in visible range. The quantum confinement effect of ZnO nanocrystals, the presence of Cu and Zn atoms and absence of defects in ZnO layer are believed responsible for the characteristics of the photoluminescence spectra. [Copyright &y& Elsevier]