Search

Abstract: Spherical SiO2 particles have been successfully coated with zinc borate layers through a self-assembly process. The resulted SiO2–Zn5B4O11 core–shell nanospheres were characterized by X-ray diffraction (XRD), infrared spectra (IR), transmission electron microscopy (TEM) and scanning electron microscopy (SEM) equipped with an energy-dispersive X-ray spectrometer (EDS). The obtained SiO2–Zn5B4O11 core–shell nanospheres have perfect spherical shape with narrow size distribution (average diameters 50 nm), i.e., the cores with mean diameters of 40 nm and the shells with an average thickness of 5 nm, monodisperse and smooth surface. Moreover, the friction coefficient of the base oil was decreased by the addition of SiO2–Zn5B4O11 core–shell nanospheres. [Copyright &y& Elsevier]

Abstract: Anatase microspheres composed of close-packed TiO2 nanoparticles were obtained hydrothermally in the presence of the surfactant 1-hexadecanamine (C16H33NH2). A probable mechanism was proposed. The resulted composite material shows a novel room temperature photoluminescence, which confirms the fact that this process could be employed to produce nanoparticles exhibiting unique optical properties of theoretical as well as practical interest. [Copyright &y& Elsevier]

Abstract: Hydrophobic CaCO3 nanoparticles were prepared in aqueous solution via carbonation method by mimicking biomineralization. In this paper, C17H35COONa solution synthesized by C17H35COOH and NaOH was used as organic substrate and growth medium for CaCO3. This organic substrate not only could induce the nucleation and growth of CaCO3 but could also make the surface of CaCO3 hydrophobic. The spindle-like CaCO3 with a diameter of about 10 nm, the ratio of diameter to length about 1:4, was prepared. According to the floating ratio test, the active ratio of the products exceeded 99% at an appropriate condition. [Copyright &y& Elsevier]

Abstract: The MoS2 nanorods were successfully synthesized by redox reaction in the aqueous solution. The microstructures and chemical compositions of the as-obtained samples were studied by X-ray diffraction (XRD), transmission electron microscopy (TEM) equipped with EDS and differential thermal analysis (DTA) in air. It has been found that the as-prepared materials have a rod-like shape with lengths of 50–150 nm and diameters of 20–40 nm. The possible reaction route, the influences of surfactant on the formation of MoS2 nanorods and the growth mechanism of MoS2 nanorods were discussed. [Copyright &y& Elsevier]

Abstract: The hollow SiO2/Al2O3 spheres with uniform mesopores in the shell wall have been successfully synthesized by a sol–gel process in an oil/water/oil (O/W/O) microemulsion. The intact hollow spheres are obtained by washing the as-synthesized solid produces with boiling water to remove the organic components. A large amount of silanol groups are retained in the hollow spheres by this facile route without calcination, and the possible agglomeration of the spheres and collapse of hollow structures are effectively avoided. The diameter and shell thickness of the spheres are measured by scanning electron microscope (SEM) and transmission polarized light microscope, which are ca. 10 and 2 μm, respectively. TEM image and N2 adsorption–desorption isotherms suggest that uniform mesopores are present in the shell wall of hollow SiO2/Al2O3 spheres after treatment with boiling water. 27Al NMR spectrum indicates almost all of aluminium species of hollow SiO2/Al2O3 spheres are in the four-coordinated environment. [Copyright &y& Elsevier]

Nanocrystalline Li0.5Fe2.1Cr0.4O4 ferrites were prepared by using the polyethylene glycol (PEG) gel method. Their structure, morphology and magnetic properties were studied by X-ray diffraction (XRD), transmission electron microscopy (TEM), VSM and Mo¨ssbauer spectroscopy. The saturation magnetization decreases with decreasing particle size. The decrease in magnetization results from nonmagnetic layer, existing at the surface of the ferrite particles, the thickness of which is 1.1 nm. As the particle size becomes smaller, a superparamagnetic behaviour appears. [Copyright &y& Elsevier]

Abstract: CaCO3/polystyrene inorganic/organic composite nanoparticles (80 nm) with a core/shell structure were obtained by in situ emulsion polymerization of styrene (St) on the surface of modified CaCO3 nanoparticles. The nanometer CaCO3 slurry was prepared via carbonation of a Ca(OH)2 slurry in the presence of sodium oleate at room temperature in order to introduce polymerizable groups onto its surface. TEM photographs of composite particles with a well-defined core-shell structure gave direct evidence of encapsulation. In addition, TGA and FT-IR spectra of the products after extraction indicated tight encapsulation between PS and CaCO3. [Copyright &y& Elsevier]

Abstract: The amorphous MoS2 nanospheres were successfully synthesized through a facile and an inexpensive synthetic process. The microstructures and chemical compositions of the as-obtained samples were studied by X-ray diffraction (XRD), transmission electron microscopy (TEM) equipped with an energy-dispersive X-ray spectrometer (EDS). It has been found that the as-prepared materials display nanospheres morphology with mean diameters of 30 nm. The possible reaction route, the influence of surfactant on the formation of MoS2 morphology, the different pH values of the solution on synthesis of pure amorphous MoS2 and the reaction temperature on the size of MoS2 were discussed. [Copyright &y& Elsevier]