超细掺锑SnO2制备工艺中前驱体洗涤分离的研究

Sb-doped SnO₂ ultrafine powders were prepared via oxidation-coprecipitation. Also the relation between surface characteristic (i.e. charged status and solvation) and precursor separation was studied. The results showed that the filter washing speed of precursor can be improved by reduced Precursor |ζ| values or lessen Precursor solvation. For example, adding to little organic solvents (such as ethanol )in Washing liquid morely accelerates to separation speed of precursor. This method and principle of washing and separation precursor can be used by other nona powders preparation with precipitation method, also sb doped SnO₂ ultrafine powders will be prepared easily in industry with it.     

电化学法制备高热稳定性锐钛矿型纳米TiO2

Titanium alkoxides were prepared by anodic dissolution of metallic titanium in absolute ethanol in the presence of HN(C₂H₅)₂*HCl (electro－conductive additives).The solution was directly hydrolyzed to prepare nanocrystalline of TiO₂ (about 10nm)by a sol－gel process.The precursor gels was calcined at T=450 ℃ and 720 ℃for 30 min,and nanocrystalline of TiO₂ (anatase) with high textural and thermal stability was obtained.FTIR,XRD,TEM,were used to characterize the structure of titanium alkoxides and nanocrystalline of TiO₂.The characteristics of nanocrystalline of TiO₂ was depended on the properties of titanium alkoxides.The Ti(OEt)₄ as a source of titanium yielded the best textural and thermal stability nanocrystalline of TiO₂.     

锂离子电池正极材料LiMn2O4的合成与晶体结构（英）

Spinel LiMn₂O₄ powders were prepared using two-step synthesis method consisting of solid-state reaction method and citrate modified sol-gel method. The effects of the calcination temperature and the Li/Mn ratio of raw materials were studied on the physicochemical and electrochemical properties of the spinel LiMn₂O₄ powders, such as crystallinity, lattice constant and density. The title compound was characterized by powder X-ray diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Polycrystalline LiMn₂O₄ powers calcined at 750 ℃ were found to be composed of very uniformly-sized microcrystal with an average particle size of 300 nm. The improvement in electrochemical properties was mainly attributed to the process of re-grinding by absolute alcohol.     

非晶态羧酸盐法合成NTC热敏陶瓷用Ni1.0Co0.2Mn1.8O4纳米粉体的研究

Nano-crystalline Ni_1.0Co_0.2Mn_1.8O₄ powders were synthesized via non-crystalloid precursor method. The results on the precursor by XRD and IR techniques show that the stable non-crystalloid precursor could be formed by adding oleic acide and adjusting the pH values. The dried precursor exhibited auto-catalytic combustion behavior. After being calcined at 800 ℃, the Ni_1.0Co_0.2Mn_1.8O₄ powders with spinel structure were obtained. It has been demonstrated that the synthesized powder is well dispersed and with higher sintering activity. The Model of non-crystalloid precursor has been suggested. The reaction mechanism has also been proposed.     

纳米二氧化钛粉末的溶胶-凝胶法合成及晶相转化

Nanosized TiO₂ powder with anatase and rutile structures was synthesized by a sol-gel method using TiCl₄ ethanol solution as a precursor.The grain size of TiO₂ powder was about 63nm after the precursor was calcined at 600℃ for 2 hours .The experimental techniques of XRD,TEM and Particle Distribution were used to characterize the synthesized specimens. Various special effects were investigated for their contribution to crystal structure and the size of TiO₂ powder .The formation of anatase as well as the rutile phase of TiO₂ was indicted from the XRD when the reaction temperature was above 30℃ and when the sol was irradiated by infrared rays .However, an anatase TiO₂ powder formed after the heat treatment of the dried gel in a temperature range from 300℃ to 500℃.Under the vacuum drying and with the calcined time below 3hours ,the anatase phase was gained .As well as with the increase of gelatinizing time, the anatase TiO₂ powder was obtained.     

溶剂热制备氧化锌纳米线

ZnO nanowires were synthesized mildly through an absolute alcohol solvothermal process at 120 ℃ for 12 h using ZnAc₂·2H₂O and NaOH as raw materials and PEG400 as a soft template. The cyrstal structure and morphology of the nanowires were characterized by XRD, SEM, TEM and HRTEM. The results indicate that the diameter of ZnO nanowires is 40 nm, the length can reach 2 μm and the nanowires are of high purity, homogeneity and well crystallinty. The influence of the various factors on the formation of ZnO nanowires and formation mechanism were also discussed.     

纳米晶氧化镍的制备及表征

Nano-NiO powder was prepared by thermal decomposition of the precursor of NiC₂O₄·2H₂O obtained via Ni(NO₃)₂·6H₂O and H₂C₂O₄·2H₂O reacting in ethanol solvent. IR and TGA-DTA indicate physisorption and chem- isorption ethanol co-exist in the precursor. XRD suggests the obtained cubic NiO is stable below 700 ℃. TEM shows the as-calcined NiO at 400 ℃ for 2 hours was of narrow distribution, weak agglomeration and small particle size (average 8 nm). The reason for weak agglomeration was explained.     

铟锡氧化物纳米网的微波法制备及其光催化特性研究

By using ultrasonic and chemical liquid coprecipitation, the precursor was prepared with high purity In, SnCl₄·5H₂O and urea. The In₂O₃·SnO₂ nanonets were obtained from precursor by heating in microwave oven. The powders were characterized by XRD, TEM. The analyzed results show the sample is In₂O₃·SnO₂, and In₂O₃is rhombohedral system while SnO₂ is tetragonal system. The sample is in spherical grain shape, with average granularity of 35 nm, and the mesh diameter of 10～80 nm. The sample was with fluorescence and good photocatalytic performance for degradation of organic dyestuff.     

溶剂热合成具有纳米孔结构的γ -Al2O3

Nanoporous gamma aluminum oxide (γ-Al₂O₃) was synthesized by solvothermal method in the presence of AlCl₃·6H₂O, urea and alcohol. The calcined sample was characterized by XRD, FTIR, TEM, and Nitrogen adsorption-desorption measurement. Results show that the obtained γ-Al₂O₃ is well-dispersed nanoparticles with particle size of 4～7 nm and the product has nano-pore structure with a narrow pore size distribution of 5～20 nm.     

有机溶液中电化学制备纳米MgTiO3

In a cell without separating the cathode and anode spaces, the precursor MgTi(OCH₂CH₃)_(6-y)(acac)_y of the mixed oxide MgTiO₃ was directly synthesized by electrochemical dissolution of titanium for 4 hours and then of magnesium for 1 hour 40 minutes at the current of 0.2 A in ethanol and acetyl-acetone solution. The nano- MgTiO₃ powder was prepared by a direct sol-gel process of the electrolyte solution under pH≈8.5 followed by washing, drying in vacuum for 24 h, and calcination at 500 ℃ for 2 h. IR and Raman spectroscopy, XRD, and TEM were used to investigate the structure of nano-MgTiO₃ and its precursor. The result suggested that it was more appropriate to control the temperature between 35～40 ℃ and the concentration of conductive additive (Bu₄N)Br at 0.04 mol·L^-1. The xerogel with an average particle size of 12 nm and the nano-MgTiO₃ of 20 nm was thus obtained in a high purity.