简捷水热前驱物技术制备钛酸钡纳米棒与纳米球

A facile synthesis route has been developed to prepare barium titanate nanoparitcles via a low temperature (120 ℃) hydrothermal decomposition of single-source metal-organic precursor. A mixture of tetramethylammonium hydroxide (TMAH) and distilled water was used as reaction media, and Barium titanium ethyl-hexano- isoproxide [BaTi(O₂CC₇H₁₅)(OC₃H₇)₅] was used as precursor. The architecture of products can be selectively controlled from nanorods to nanospheres by adjusting the precursor′s concentration in the reaction system. Powder X-ray diffraction (XRD) analysis indicated that the products were in cubic phase. Transmission electronic microscopy (TEM) observation showed that the nanospheres were 30～50 nm in diameter, and the nanorods were 5～10 nm in diameter and 100～600 nm in length, respectively. Phase transformation behavior of the as-prepared products was also investigated.     

储氧材料制备过程中的结构及织构变化

Ce_0.65Zr_0.35O₂ solid solution was prepared by co-precipitation method and characterized by X-ray diffraction (XRD), Raman spectra, BET, oxygen storage capacity (OSC) and temperature-programmed reduction measurements (H₂-TPR) after calcination at 100 ℃, 300 ℃, 600 ℃, and 1 000 ℃. The results showed that the precipitation was a crystalline of fluorite structure, and in the process of the precipitation transformation into Ce_0.65Zr_0.35O₂ solid solution, the fluorite structure of the precipitation kept unchanged. The samples had different BET surface areas and OSC at different temperatures, but they held the performance of stable structure. After 1 000 ℃, there didn′t appear the other crystalline phase. So the samples prepared by co-precipitation method had excellent texture and higher thermal stability.     

反相微乳液法合成SrTiO3纳米棒

SrTiO₃ nanorods were synthesized in cetanyl trimethyl ammonium bromide (CTAB) reverse microemulsion containing CTAB, n-hexanol, n-octane and water with Ba(OH)₂ as reactants. The effects of different conditions such as ω₀ [ω₀=n_H2O/ n_CTAB], aging time and the concentration of reactants on the formation of the nanorods were studied. Transmission electron microscope (TEM), electron diffraction (ED) and X-ray diffraction(XRD)were used to characterize the morphology and the structure of the synthesized nanorods. The results show that SrTiO₃ nanorods with a length of 260～2 000 nm and a diameter of 50～100 nm belonging to single crystal are single cubic system. The molar ratio of Sr to Ti of products is 1.0 as determinded by ICP.     

氧化锌纳米棒的制备和生长机理研究

ZnO nanorods are prepared by different assistants (cetyltrimethylammonium bromide，trisodium citrate and ethylene diamine anhydrous) favored hydrothermal synthesis with Zn(OH)₂ colloid as the precursor. The samples are characterized by transmission electron microscopy (TEM) and X-ray diffraction (XRD). The results show that the as-synthesized ZnO nanorods are of uniform size with 25 nm in diameter and 200～300 nm in length. The effects of the different assistants to the morphology, size and mechanism of nano-ZnO are discussed.     

微波辐照方式对CdS和Bi2S3纳米粒子结晶度的影响

The effect of traveling microwave irradiation on the crystallinities of CdS nanoparticles and Bi₂S₃ nanorods was studied. Results showed that as compared with stationary microwave irradiation the crystallinities and the crystal growth of sulfide nanoparticles were improved. Traveling microwave irradiation can supply narrower frequency distribution and stronger power density of irradiation， CdS nanoparticles and Bi₂S₃ nanorods obtained are better in crystallinities and larger in size than under stationary microwave irradiation.     

水菱钇型碳酸钕的形成及聚甘油脂肪酸酯对结晶的影响

Amorphous Neodymium carbonate was prepared by the precipitation reaction of neodymium chloride with ammonium bicarbonate in solution, and then aged at 60 ℃ to form crystalline neodymium carbonate. The feed molar ratio of n_(NH4HCO3)/n_(NdCl3 was 2.5, and the precipitation was carried out with or without addition of polyglyceryl fatty acid ester (PGFAE). The phase type and morphology of crystalline neodymium carbonates were examined by XRD and SEM, and the effect of PGFAE on the crystallization speed was investigated by volume change in deposit layer and in situ pH determination. The content of neodymium and chloride in crystals was analyzed, and the crystallization reaction or crystal growth characteristics were discussed. It was found that all the crystalline neodymium carbonates were tengerite type, and contained less crystalline water and chloride than that of lanthanite type neodymium carbonate crystallized at room temperature, which is beneficial to the production of neodymium carbonate with higher neodymium and lower chloride content. The addition of PGFAE not only could eliminate the foam formed during precipitation, but also could shorten crystallization time, and form large radiative-like shape conglomeration by the irregulative linkage of one dimension needle crystals. It is also suggested that the morphology and the chloride content of neodymium carbonate were dependent on the structure and crystal growth characteristics.     

羟基功能化离子液体中Ag纳米材料的制备及结构表征

Ag nanoparticles were prepared using hydroxyl-functionalized ionic liquids as reductant and reaction medium. Nanoparticles with different particle sizes were obtained by using ionic liquids with different structures, while nanorods were harvested when the reaction temperature was increased. The materials obtained were investigated by XRD and TEM. The results indicate that the crystal is in face-centred cubic structure for both of Ag nanoparticles and nanorods, and the diameter of Ag nanoparticles prepared in 1-ethoxyl-3-methyl imidazolium tetrafluoroborate ([C₂OHmim]BF₄), 1-(4′-hydroxyl)butyl-3-methyl imidazolium tetrafluoroborate ([C₄OHmim]BF₄) and 1-(6′-hydroxyl)hexyl-3-methyl imidazolium tetrafluoroborate ([C₆OHmim]BF₄) ionic liquid is about 25, 15 and 10 nm, respectively. And the diameter of Ag nanorods is about 200 nm and 2 μm in length. Finally, the formation mechanism of Ag nanoparticles and nanorods is proposed.     

离子层气相反应法(ILGAR)制备CuInS2薄膜的研究

CuInS₂ thin films have been prepared by ion layer gas reaction (ILGAR) using C₂H₅OH as solvent, CuCl and InCl₃ as reagents and H₂S gas as sulfuration source. The effects of cationic concentrations and numbers of cycle on the properties of CuInS₂ film were investigated. The chemical composition, crystalline structure, surface topography, deposited rate, optical and electronic properties of the films were characterized by X-ray diffractrometry (XRD), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), ultraviolet-visible spectrometry (UV-Vis) and Hall System. The results show that the crystalline of CuInS₂ thin films and the deposition rate have been improved with the increase of cationic concentration, while CuxS segregation phases appear with further increasing cationic concentration. The deposition rate is close to constant as cationic concentration is fixed. CuInS₂ thin film derived form lower cationic concentration is uniform, compact and good in adhesion to the substrates. The absorption coefficient of CuInS₂ thin films is larger than 10⁴ cm^-1, and the band gap E_g is in the range of 1.30～1.40 eV. The dark resisitivity of the thin film decreases from 50 to 10 Ω·cm and the carrier concentration ranges are over 10¹⁶ cm^-3.     

Si5P6O25∶Tb3+的结构与荧光性质

Tb³⁺ ions were incorporated in P-Si matrix material through a sol-gel process. Luminescence properties of Tb³⁺ as a function of dopant， firing temperature， composition and structure of matrices were investigated. The gels synthesized by the reaction of P₂O₅ or H₃PO₄ with tetraethoxy silane and TbCl₃ as dopant were fired in air from the temperature 25～1000℃ to form P-Si crystalline phase. The crystal structure was determined by powder X-ray diffraction. Si₅O(PO₄)₆ were the only crystalline phase and belong to hexagonal crystal system. The emission of ⁵D₄-⁷F₅(～545nm) transition of Tb³⁺ in the P-Si system is composed of two peaks. The amount of doping Tb³⁺ varied from 0.664% to 1.644%， and no obvious concentration quenching was observed in this doping concentra-tion range. The intensity of Tb³⁺ emission increased with firing temperature increasing and becomes stable at 800～1000℃.     

SnO2/ 石墨复合材料作为锂离子电池负极材料研究

Nano-scale SnO₂ powders were prepared by hydrolyzation. Graphite was poured into the SnCl₄ solution during hydrolyzation. After drying and calcining at 360 ℃, the negative electrode composite material of nanosized SnO₂ and graphite was obtained. The composite materials were characterized by X-ray diffraction (XRD) and transmission electron microscopy (TEM). The average crystallite size was in the range of 15～20 nm. Electrochemical lithium insertion/extraction was studied preliminarily on the obtained composite. The discharge capacity of nanosized SnO₂ / graphite composite was found to have a high electrochemical reversible capacity for Li-ion insertion and extraction, which possessed the advantages of both higher discharge capacity of SnO₂ and lower discharge potential of graphite. In addition, the cycle capability was also improved due to the inhibiting effect of the composite against pulverization and agglomeration to a certain extent during Li-ion insertion and extraction.