Y Zhou

A convenient ultraviolet irradiation technique for in situ synthesis of CdS nanocrystallites at room temperature

CdS nanocrystallites with cubic or hexagonal phase structures have been synthesised at room temperature via precipitation of Cd2+ ions with homogeneously released S2− ions, generated from the decomposition of thio-acetamide by ultraviolet irradiation reduction.

Preparation and studies of Ag–TiO2 hybrid nanoparticles of core-shell structure

Abstract Ag–TiO 2 hybrid nanoparticles of core-shell structure were synthesized by an ultraviolet irradiation reduction technique. Phase analysis of the product obtained was carried out by X-ray and electron diffraction patterns. The morphology of the hybrid particles was studied by TEM images. The variation of UV-Vis absorption spectra of the silver colloidal solution with incorporation of TiO 2 was observed. A strong surface-enhance Raman scattering (SERS) and Raman blue shift of TiO 2 was found in Ag–TiO 2 hybrid nanoparticles due to the amalgamation of Ag.

Synthesis of α-Fe ultrafine particles in a saturated salt solution/isopropanol/PVP microemulsion and their structural characterization

Abstract A new microemulsion system consisting of saturated Fe 2+ solution/isopropanol/PVP system was used to synthesize magnetic α-Fe ultrafine particles by reduction reaction. Samples were characterized by X-ray diffraction (XRD) and transmission electron microscopy (TEM). Results show that there is an important relationship between particle size, particle morphology, and the volume ratio of water to isopropanol. Due to the special surface properties of nanostructural α-Fe, there were iron oxides outside the α-Fe nanoparticles; these oxides may prevent the inner α-Fe from being oxidized further.

Synthesis and characterization of NiP-TiO2 ultrafine composite particles

Ultrafine particles TiO2-NiP were successfully synthesized by an electroless plating technique. TEM and XRD were used to characterize the particles’ morphology and composition.

A novel ultraviolet irradiation technique for fabrication of polyacrylamide-metal (M = Au, Pd) nanocomposites at room temperature

Polyacrylamide (PAM)–metal (M = gold, palladium) nanocomposites with metal nanoparticles homogeneously dispersed in the polymer matrix have been prepared via a novel ultraviolet irradiation technique at room temperature, which is based on the simultaneous occurrence of photo-reduction formation of the colloidal metal particles and photo-polymerization of the acrylamide (AM) monomer. The UV–vis absorption spectra and TEM were employed to characterize the M-PAM nanocomposites by different irradiation times. The average sizes of the colloidal gold and palladium particles dispersed in the nanocomposites were calculated by XRD patterns and TEM images. The present method may be extended to prepare other metal–polymer hybrid nanocomposite materials.

Preparation of metal or alloy sulfide nanoparticles by electrochemical deposition

ZnS and (PbSn)S nanoparticles were successfully fabricated by an electrochemical deposition with alternating current circuit (EDACC). The mechanism of product formation is presented in this paper. It is obvious that nanoparticles of many metal sulfides or alloy sulfides can be synthesized by this method.

Preparation of nanocrystalline silver by the method of liquid-solid arc discharge combined with hydrothermal treatment

Abstract A technique of liquid–solid arc discharge combined with hydrothermal treatment in the presence of surfactant has been successfully developed to prepare nanocrystalline noble metallic Ag with an average particle size of about 10 nm. The products were characterized by adsorption spectroscopy, X-ray diffraction (XRD), transmission electron microscopy (TEM), and microscope photodensitometer measurements. The influence of preparation conditions on the size of Ag particles was investigated. The appearance of Ag nanowires in the process was observed.

Synthesis of Fe3O4 powder by a novel arc discharge method

Abstract Magnetite Fe 3 O 4 ultrafine powder, a magnetic material, was synthesized by a novel arc discharge method of metallic iron filaments in NaCl electrolyte. The products were characterized by X-ray diffraction (XRD) and transmission electron microscopy (TEM). The size and the shape of the products were influenced by the voltage between the two metallic iron filaments.

Solvothermal synthesized LiMn1−xFexPO4@C nanopowders with excellent high rate and low temperature performances for lithium-ion batteries

Mixed-carbon coated LiMn1−xFexPO4 (x = 0, 0.2, 0.5, 1) nano-particles are synthesized by a novel solvothermal approach. All of these powders possess a uniform particle size distribution around 150 nm and a carbon coating layer of about 2 nm. The LiMn1−xFexPO4@C samples with a carbon content of 2 wt% have an optimal electrochemical performance. The average voltage platform of LiMn1−xFexPO4@C increases with the increased Mn/Fe ratio, but declines gradually during electrochemical cycling. The LiMn0.5Fe0.5PO4 sample shows a high energy density (568 W h kg−1), good cycleability (97.1%, 100 cycles) and excellent rate capability (120.2 mA h g−1, 20C) at room temperature. Simultaneously, the LiMn0.5Fe0.5PO4 and LiFePO4 samples also show excellent low temperature electrochemical performance with specific capacities of 109.4 and 138.8 mA h g−1 with average discharge voltages of 3.476 V and 3.385 V, respectively, at −12 °C. Even at −20 °C, their discharge specific capacities are 71.7 and 82.3 mA h g−1 at 3C, respectively.

A high energy density full lithium-ion cell based on specially matched coulombic efficiency

Nano-spherical Li-rich cathodes and MnxCo1−xO anodes are synthesized from as-solvothermal MnxCo1−xCO3 (x = 1, 0.8, and 0.5) precursors. Based on the half-cell studies of these materials, Li-rich 0.5Li2MnO3·0.5LiMn0.5Ni0.5O2 with a high reversible capacity of 247 mA h g−1 and binary transition metal oxide Mn0.8Co0.2O with a reversible capacity of 759 mA h g−1 are selected respectively as the optimal positive and negative electrodes to construct a full cell. Such an electrode match-up, i.e. Li-rich/Mn0.8Co0.2O full cell (“N-cell”), allows no need for pre-activation of the metal oxide anode. This “N-cell” can deliver a high reversible capacity of 205 mA h g−1 and particularly rather high volumetric energy density, which is about 31% higher than that of a Li-rich/graphite full cell (“T-cell”). The special coulombic efficiency match-up and tailored microstructures and compositions of the electrode materials are all crucial to achieve such a high energy density.