Y.T. Qian

A nitrogen-doped graphene/carbon nanotube nanocomposite with synergistically enhanced electrochemical activity.

A new kind of nitrogen-doped graphene/carbon nanotube nanocomposite can be synthesized by a facile hydrothermal process under mild conditions, which exhibits synergistically enhanced electrochemical activity for the oxygen reduction reaction. This research provides a new route to access a metal-free electrocatalyst with high activity under mild conditions.

Hydrothermal Preparation and Characterization of Nanocrystalline Powder of β-Indium Sulfide

Abstract β-In 2 S 3 powders with particles having an average size of 13 nm and spherical shape have been successfully prepared through the hydrothermal treatment of a sol from indium trichloride and sodium sulfide at 140°C. The effects of temperature, time, and the pH value of the sol on the formation of the nanocrystalline β-In 2 S 3 powders were investigated. The products were characterized by powder X-ray diffraction (XRD), transmission electron micrography (TEM), and IR spectroscopy.

An aqueous approach to ZnSe and CdSe semiconductor nanocrystals

With the use of elemental metals and selenium as resource materials, ZnSe and CdSe nanocrystals have been prepared through an aqueous method at temperature as low as 80°C in alkaline medium. The products were characterized by powder X-ray diffraction pattern (XRD), transmission electron microscopy (TEM) and X-ray photoelectron spectrum (XPS). Two kinds of chemical mechanisms for the formation of the products and the influence of experimental conditions are discussed.

Benzene-thermal preparation of nanocrystalline chromium nitride

Abstract Nanocrystalline CrN was successfully prepared through the liquid–solid reaction of anhydrous CrCl 3 and Li 3 N, via a benzene–thermal method in the temperature range of 350–420°C, which is much lower than that used in conventional methods. This process is simple and easy to control. X-ray diffraction (XRD) indicated that the compound was cubic CrN phase with cell constant a = 4.13 A. Transmission electron microscopy (TEM) images showed that the average particle size was about 25 nm. X-ray photoelectron spectroscopy (XPS) indicated that the as-prepared products contained a small amount (less than 20%) of amorphous carbon.

Preparation and phase control of nanocrystalline silver indium sulfides via a hydrothermal route

A hydrothermal route was proposed to prepare and control nanocrystalline silver indium sulfides (orthorhombic AgInS 2 , tetragonal AgInS 2 , and cubic AgIn 5 S 8 ). The reaction was carried out in an autoclave in the temperature range of 100–280 °C with AgCl, InCl 3 , and thiourea as reactants. X-ray powder diffraction patterns and transmission electron microscopy images showed that the products were AgInS 2 and AgIn 5 S 8 phases and well crystallized with grain diameter in the range of 20–70 nm. X-ray photoelectron spectra of the single AgIn 5 S 8 phase revealed the surface stoichiometry (AgIn 5.05 S 8.11 ), and its room temperature Raman spectrum showed a strong peak at 130 cm −1 and a weak peak at around 290 cm −1 . The influence of reaction temperature on the phases in the final products was investigated. A possible reaction mechanism of the formation of silver indium sulfides was also briefly discussed.

Preparation of nanocrystalline nickel powders through hydrothermal-reduction method

Nanocrystalline nickel powders were prepared in aqueous solution through a thermal-reduction process. The reductive atmosphere was produced from the disproportionation of white phosphorus in basic solution at 100°C. X-ray diffraction (XRD), transmission electron microscopy (TEM), and chemical analysis were employed to characterize the products. XRD revealed that the nickel was single phase. TEM showed that the average particle size was about 26 nm. The purity of the as-prepared nickel was 99.6%, as determined from the spectrophotoscopy. The possible formation mechanism of nanocrystalline nickel is a reduction of nanocrystalline Ni(OH)2.

A solvothermal route to wurtzite ZnSe nanoparticles

Zinc powder reacts with equivalent elemental selenium in solvent ethylenediamine at 120 °C for 6 h to form a complex, which is converted to ZnSe nanoparticles by pyrolysis or protonization. X-ray diffraction results suggest that the as-formed products have wurtzite structure. Transmission electron microscopy observation show that particles with spherical and laminar morphology were produced by pyrolysis and protonization, respectively. The formation of ZnSe nanoparticles is also investigated by infrared and thermal analysis.

A convenient hydrothermal route to mineral Ag3CuS2 nanorods

Abstract A convenient hydrothermal route is proposed for synthesizing mineral Ag3CuS2 nanorods. X-ray powder diffraction (XRD) patterns indicated the formation of Ag3CuS2, and elemental analysis and X-ray photoelectron spectra (XPS) revealed the stoichiometric relation between Ag, Cu, and S. Transmission electron microscope (TEM) images demonstrated that the final product consisted of nanorods with diameters from 30 to 150 nm and lengths from 200 nm to 1 μm. A possible formation mechanism of Ag3CuS2 nanorods was proposed.

The preparation and phase transition of nanocrystalline iron sulfides via toluene-thermal process

A series of nanocrystalline iron sulfides have been successfully prepared via the reaction of FeSO4.7H2O and Na2S3 using the toluene-thermal method in the temperature range of 80–170°C. Two single phases of Fe3S4 and FeS2 were obtained. Transmission electron microscopy analyses indicate that Fe3S4 crystallite is about 25 nm and FeS2 is about 50 nm. The iron and sulfur contents are determined by spectrophotometric analysis. The ratios of Fe to S are Fe2.994S4 and Fe0.996S2, respectively. With the change of the reaction condition, the phase transition among iron sulfur was studied.

Ultrafine powder of silver sulfide semiconductor prepared in alcohol solution

Abstract Ultrafine powder of silver sulfide semiconductor was prepared at room temperature between 25 and 35°C in an absolute alcohol solution, with AgNO 3 and CS 2 as the reagents. The final products were characterized by X-ray diffraction and transmission electron microscopy. The average size of the crystallites was about 50 nm. The possible chemical formation process of Ag 2 S is discussed.