Synthesis of visible light responsive ultrafine K_4Ce_2Nb_(10)O_(30) by a stearic acid method

K4Ce2Nb10O30 ultrafine powders were prepared by stearic acid method (SAM). The obtained products were analyzed by X-ray diffraction, transmission electron microscopy, energy dispersive X-ray spectrometry, scanning electron microscopy and UV-visible absorption spectra. XRD patterns revealed that K4Ce2Nb10O30 powders treated at 900 oC for 2 h presented tetragonal structure without the presence of deleterious phases. Furthermore, the K4Ce2Nb10O30 prepared by SAM had considerable activity under visible light irradiation.

Synthesis of CaCu_3Ti_4O_(12)powders and ceramics by sol-gel method using decanedioic acid and its dielectric properties

The CaCu3Ti4O12 xerogels, powders and ceramics were prepared through the sol-gel method using two kinds of organic acid （decanoic acid and decanedioic acid）. The xerogels, powders and ceramics were characterized by the methods of TG-DTG, FT-IR, XRD, SEM and TEM. The dielectric properties of the ceramics were also measured. The results indicated that the powders calcined at 850 ℃ for 2 h are both nanometer scale particles. After sintering, the ceramics mainly consist of the CaCu3Ti4O12 phase. Compared with the powders prepared using monoacid, the particle size of the powders prepared using diacid obviously increases, and the grain size, the relative density and the whole permittivity of the ceramics increase as well. Specially, the ceramic prepared using decanedioic acid has higher relative density （97.3%）, dielectric constant （316 808） and lower dielectric loss （0.242 5） at 30 ℃ （10 kIaz）

Synthesis of piezoelectric nanocrystalline PZT powder by stearic acid gel method

PZT nanocrystalline powder was prepared by a stearic acid gel method. Thecrystallization process from the precursor was monitored by infrared spectroscopy, differentialthermal analysis, and thermogravimetric analysis. The nano-sized PZT powder was characterized byX-ray diffraction and transmission electron microscopy. It shows that pure single-phase PZT powdercould be obtained at 450 deg C for 1 h, and the particle size is about 20 nm. With an increase inthe calcination temperature, the PZT crystallite size increased.

Research on the High-Strength Coating Preparation Methodology based on Acid Catalytic and Sol-Gel Method

In this paper, we conduct research on the high-strength coating preparation methodology based on acid catalytic and Sol-Gel method. This method has been widely used in the preparation of various functional thin film, film and protective film structure, etc. As a result of sol gel process continuously broaden the application field, this method has been more and more get the favor of people. Compared with other traditional preparation methods of inorganic material, sol-gel process has many characteristics. To adjust the solution acidity and add a small amount of acid or alkali can have the effect of＂ catalyst, its reaction process on sol to get and gel structure may also be affected. Our research analyze the topic theoretically and numerically which is meaningful.

Preparation and optical characteristics of ZnO films by chelating sol-gel method

The effect of different annealing temperatures on the structure, morphology,and optical properties of ZnO thin films prepared by the chelating sol-gel method was investigated.Zinc-oxide thin films were coated on quartz glass substrates by dip coating. Zinc nitrate, absoluteethanol, and citric acid were used as precursor, solvent, and chelating agent, respectively. Theresults show that ZnO films derived from zinc-citrate have lower crystallization temperature (below400℃), and that the crystal structure is wurtzite. The films, treated over 500℃, consist ofnano-particles and show to be porous at 600℃. The particle size of the film increases with theincrease of the annealing temperature. The largest particle size is 60 nm at 600℃. The opticaltransmittances related to the annealing temperatures become 90% higher in the visible range. Thefilm shows a starting absorption at 380 nm, and the optical band-gap of the thin film (fired at500℃) is 3.25 eV and close to the intrinsic band-gap of ZnO (3.2 eV).

Improved activity of Ni-Mo/SiO_(2) bimetallic catalyst synthesized via sol-gel method for methylcyclohexane cracking

To improve the cracking behavior of hydrocarbon,Ni-Mo/SiO_(2) bimetallic catalysts were synthesized by different preparation methods(sol-gel,co-impregnation and single-impregnation) and added the additives(citric acid,polyethylene glycol and cetyltrimethylammonium bromide) based on the most suitable method above.The cracking reaction of methylcyclohexane under supercritical conditions was performed as the probe reaction to estimate the catalytic performance,and the properties of Ni-Mo/SiO_(2) catalyst were characterized by N_(2) absorption-desorption,XRD,XPS,H_(2)-TPR,NH_(3)-TPD,in-situ IR of NH_(3) desorption,HRTEM and STEM-mapping so as to study the structure-activity relationship.The catalyst synthesized via sol-gel method showed the best conversion and heat sink,being 81.8% and 3.81 MJ/kg,which was closely related to strong mutual effect between active components and SiO_(2) as well as strong acid sites.Besides,the introduction of additives by sol-gel method has an affirmative influence on properties of Ni-Mo/SiO_(2) catalysts,being that the acidity(more L and B acid sites) was modulated and organic groups interact with metal to suppress the aggregation of metal species(Ni and Mo),thereby enhancing the catalytic activity.At 750℃,the conversion(89.3%) as well as heat sink(3.99 MJ/kg) of MCH cracking obtained an optimum over Ni-Mo/SiO_(2) catalyst with addition of citric acid.

Preparation and electrochemical performance of Li_2Mn_(0.5)Fe_(0.5)SiO_4 cathode material with sol-gel method for lithium ion batteries

Li2Fe0.5Mn0.5SiO4 material was synthesized by a citric acid-assisted sol-gel method. The influence of the stoichiometric ratio value of n(citric acid) to n(Fe2+-Mn2+) on the electrochemical properties of Li2Fe0.5Mn0.5SiO4 was studied. The final sample was identified as Li2Fe0.5Mn0.5SiO4 with a Pmn21 monoclinic structure by X-ray diffraction analysis. The crystal phases components and crystal phase structure of the Li2Fe0.5Mn0.4SiO4 material were improved as the increase of the stoichiometric ratio value of n(citric acid) to n(Fe2+-Mn2+). Field-emission scanning electron microscopy verified that the Li2Fe0.5Mn0.5SiO4 particles are agglomerates of Li2Fe0.5Mn0.5SiO4 primary particles with a geometric mean diameter of 220 nm. The Li2Fe0.5Mn0.5SiO4 sample was used as an electrode material for rechargeable lithium ion batteries, and the electrochemical measurements were carried out at room temperature. The Li2Fe0.5Mn0.5SiO4 electrode delivered a first discharge capacity of 230.1 mAh/g at the current density of 10 mA/g in first cycle and about 162 mAh/g after 20 cycles at the current density of 20 mA/g.

LA-SA\MMA相变微胶囊的制备及其性能研究

通过原位聚合法,制备了以甲基丙烯酸甲酯为壁材,月桂酸、硬脂酸共熔物为芯材的相变微胶囊LASA\MMA相变微胶囊。利用SEM扫描电镜、差示扫描量热仪、马尔文粒径分析仪、傅里叶红外光谱分析仪和TG热重分析仪观察并检测不同芯壁比的微胶囊,结果显示:芯壁比为4:5微胶囊呈圆球状、表面光滑平整,但是略微存在团聚粘着现象。囊壁对芯材起到了一定的保护作用,有效地提高微胶囊的热稳定性。微胶囊耐久性十分优异,可以多次重复使用。然后,使用干法涂层技术把不同质量分数的相变微胶囊涂覆到SMS织物上,产生相变温控织物。通过热成像,讨论经过相变微胶囊涂层整理后的织物,其蓄热控温性能是否受到影响。结果显示:经过涂层整理后的织物,其降温速率下降变慢,能够应对外界环境温度的变化。

A new solid acid SO_4^(2-)/TiO_2 catalyst modified with tin to synthesize 1,6-hexanediol diacrylate

A new solid acid catalyst,SO4^2-/TiO2 modified with tin,was prepared using a sol-gel method and its physicochemical properties were revealed by nitrogen adsorption-desorption,X-ray powder diffraction,scanning electron microscopy,Fourier transform infrared spectroscopy,infrared spectroscopy of adsorbed pyridine,temperature-programmed desorption of ammonia and thermal gravimetric analysis.The structure,acidity and thermal stability of the SO4^2-/TiO2-SnO2 catalyst were studied.Incorporating tin enlarged the specific surface area and decreased crystallite size of the SO4^2-/TiO2 catalyst.The total acid sites of the modified catalyst increased and Bronsted acid strength remarkably increased with increasing tin content.The decomposition temperature of sulfate radical in the modified catalyst was 100 ℃ greater and its mass loss was more than twice that of the SO4^2-/TiO2 catalyst.The SO4^2-/TiO2-SnO2 catalyst was designed to synthesize 1,6-hexanediol diacrylate by esterification of 1,6-hexanediol with crylic acid.The yield of 1,6-hexanediol diacrylate exceeded 87% under the optimal reaction conditions：crylic acid to 1,6-hexanediol molar ratio = 3.5,catalyst loading = 7%,reaction temperature = 130 ℃ and reaction time = 3 h.The modified catalyst exhibited excellent reusability and after 10 cycles the conversion of 1,6-hexanediol was above 81%.

Sol-Gel Synthesis Using Novel Chelating Agent and Electrochemical Characterization of Binary Doped LiMn2O4 Spinel as Cathode Material for Lithium Rechargeable Batteries

LiMn2O4 and LiCuxCryMn2-x-yO4 (x = 0.50;y = 0.05 - 0.50) powders have been synthesized via sol-gel method for the first time using Myristic acid as chelating agent. The synthesized samples have been taken to physical and electrochemical characterization such as thermo gravimetric analysis (TG/DTA), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), field-emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM) and electrochemical characterization viz., electrochemical galvanostatic cycling studies, electrochemical impedance spectroscopy (EIS) and differential capacity curves (dQ/dE). XRD patterns of LiMn2O4 and LiCuxCryMn2-x-yO4 confirm high degree of crystallinity with good phase purity. FESEM image of undoped pristine spinel lucidly depicts cauliflower morphology with good agglomerated particle size of 50 nm while 0.5-Cu doped samples depict the pebbles morphology. TEM images of the spinel LiMn2O4 and LiCu0.5Cr0.05Mn1.45O4 authenticate that all the synthesized particles via sol-gel method are nano-sized (100 nm) with spherical surface and cloudy particles morphology. The LiMn2O4 samples calcined at 850℃ deliver the high discharge capacity of 130 mA·h/g with cathodic efficiency of 88% corresponds to 94% columbic efficiency in the first cycle. Among all four compositions studied, LiCu0.5Cr0.05Mn1.45O4 delivers 124 mA·h/g during the first cycle and shows stable performance with a low capacity fade of 1.1 mA·h/g cycle over the investigated 10 cycles.

Synthesis of rod-like ultrafine K_4Ce_2Nb_(10)O_(30) via a salt-assistant stearic acid method

A salt-assistant stearic acid method （SAM） capable of forming ultrafine K4Ce2Nb10O30 products was described. XRD pattern re-vealed that tetragonal K4Ce2Nb10O30 products could be obtained by heat treatment at 900 ℃ for 2 h. Transmission electron microscopy （TEM） observations indicated the introduction of KCl could lead to the formation of rod-like K4Ce2Nb10O30 products. The species of salts played a crucial role in fine tuning the shapes and sizes of K4Ce2Nb10O30 products. Furthermore, the K4Ce2Nb10O30 prepared by salt-assistant SAM had considerable activity under visible light irradiation.

硬脂酸复合铝粉的制备表征及声光性能研究

雾化铝粉是一种高能金属燃料,广泛应用于推进剂、可燃剂、发光剂等领域。为防止雾化铝粉氧化及吸水团聚,本研究以硬脂酸(Stearic Acid,SA)为包覆剂,通过溶液共混法对雾化铝粉进行表面包覆处理,制备了复合铝粉(SA/Al),并对复合铝粉的耐腐蚀及抗吸湿性能进行了测试。在此基础上,采用复合铝粉制备了声光剂,并测试了其安定性及声光性能。结果表明,硬脂酸可对铝粉实现有效包覆,所得复合铝粉的耐腐蚀性、抗吸湿性均有显著提高;以复合铝粉制备的声光剂声光性能有所提高,安定性良好,其中8%SA/Al的综合性能最优,其吸湿性的数值为0.0219%,仅为原料铝粉的1/60;1.5 m处声压级为179.27 dB,较原料铝粉提高了1.7 dB;发光强度为0.95×10^(7)Cd,与原料铝粉持平。

硬脂酸法制备纳米TiO_2及微结构控制

采用硬脂酸法制备了不同掺杂量的ＴｉＯ２纳米晶．通过ＦＴＩＲ、ＸＲＤ和ＴＥＭ等实验手段对所得纳米ＴｉＯ２进行分析和表征，并对反应历程进行了初步探讨．实验结果表明，利用硬脂酸法，金红石型ＴｉＯ２能在５００℃获得，掺杂Ｎａ＋和Ｋ＋后则得到锐钛矿型ＴｉＯ２，且随着掺杂量的增加，ＴｉＯ２的粒径减小．

硬脂酸溶胶—凝胶法制备超细LaCoO_3及对硝胺改性双基推进剂燃烧性能的影响研究

以硬脂酸为络合剂，采用溶胶-凝胶法制备了钙钛矿型超细复合氧化物LaCoO3．运用差热-热重（DTA-TG）、傅立叶变换红外（FT-IR）光谱、X射线衍射（XRD）、透射电镜（TEM）对生成LaCoO3的超细粉末进行了表征。比较了湿凝胶的两种干燥方法对产品团聚程度的影响。初步测试了超细LaCoO3粉体对硝胺改性双基推进剂的燃速和压力指数的影响。结果表明：干燥湿凝胶时加入干燥剂无水硫酸钠脱水比真空干燥所得粉体具有团聚程度轻，粒径小的特点；将所得的超细粉体LaCoO3按1．7％（质量百分比）比例加入硝胺改性双基推进剂中，在3～18MPa范围内，显示了提高燃速，降低压强指数的作用，且在14～16MPa压强范围内产生了平台燃烧效应。

纳米晶铁酸锌和铁酸镧的合成与表征

用硬脂酸凝胶法制备了尖晶石型ZnFe2O4和钙钛矿型LaFeO3纳米晶，通过热重差热（TG-DTA）、X射线粉末衍射（XRD）、透射电镜（TEM）和BET比表面吸附，对纳米粒子的组成、结构、形貌、粒径进行了分析和表征．

硬脂酸法制备超细K_2La_2Ti_3O_(10)及其酸交换性质研究

A new stearic acid method(SAM) has been used to prepare ultrafine K2La2Ti3O10 nanocrystalline. Each state of synthesis process was followed by the use of FT IR analysis. The resulting materials have been characterized by means of XRD, TEM, BET surface area analysis. The acid exchanging property of the obtained product was also studied. The experimental results showed that comparing with the product of traditional solid state reaction, the particle size of the K2La2Ti3O10 synthesized by SAM is greatly reduced, BET surface area is high(more than 11.83m2· g- 1) and has different acid exchanging properties. It can be easily exfoliated in 2mol· L- 1 HNO3 solution.

BaTiO_3纳米晶的合成与表征

以硬脂酸、硬脂酸钡和钛酸丁酯为原料合成了ＢａＴｉＯ３纳米晶，粒度为１０～２０ｎｍ，烧成温度为６５０℃，低于传统的合成温度。用红外光谱、差热分析、热重分析和Ｘ射线衍射对合成过程进行了研究，用透射电镜考察纳米晶的粒度和形貌。用发射光谱和Ｘ射线荧光光谱对样品纯度进行了分析。结果表明，此法合成的纳米晶ＢａＴｉＯ３纯度高、粒度小且较均匀，在常温下属立方钙钛矿型。

Y_2O_3纳米晶的制备和表征

采用硬脂酸凝胶法制备了 Y2 O3纳米晶 ,用傅立叶变换红外光谱 ( FTIR) ,热重 -差热 ( TG- DTA)对制备过程进行了表征。用 X射线粉末衍射 ( XRD) ,透射电子显微镜 ( TEM)及 BET比表面吸附对 Y2 O3纳米晶的粒径和形貌进行了表征。在 60 0℃以上热处理得到立方晶系 Y2 O3纳米晶 ,其粒径随热处理温度的上升而增大 ,形貌由球形变为立方形。粒径分布窄 ,无硬团聚现象产生。用傅立叶变换红外光谱 ( FTIR)对其谱学特性进行了研究 ,发现了表面效应驱动的吸收峰蓝移现象。

硬脂酸溶胶凝胶法-共沸蒸馏法制备钙钛矿型纳米LaCoO3

用硬脂酸溶胶凝胶-共沸蒸馏法制备了纳米LaCoO3,用差热-热重、透射电镜及红外等手段对粉体进行了表征,并对配合物溶胶-共沸蒸馏脱水的干燥机制进行了探讨。实验结果表明:硬脂酸溶胶凝胶法制备纳米粉体时,配合物溶胶的干燥脱水是不可缺少的一步。共沸蒸馏所用的溶剂苯是通过物理吸附作用替代了配合物溶胶中的水,其机理是靠降低粒子间毛细管力来减少聚集作用的,从而防止了干燥及后续煅烧阶段的粉体团聚。

硬脂酸溶胶凝胶法制备氧化镁纳米微粒的研究

以硬脂酸为分散剂 ,采用溶胶凝胶法研究了制备氧化镁纳米微粒的条件。探讨了分散剂用量、反应时间、反应温度、烧结温度和时间对产物粒径与转化率的影响 ,取得了最佳工艺条件。分别用红外光谱 (IR)、X射线粉末衍射 (XRD)、透射电镜(TEM)和比表面积 (BET)测定 ,对该纳米微粒的结构与性能进行了表征。结果表明 :Mg(NO3) 2 与CH3(CH2 ) 1 6 COOH的摩尔配比控制在 1∶4,于 90℃反应 2 0min ,在 470℃热处理 3h ,得到立方相氧化镁纳米微粒 ,形貌为椭球体 ,分散性好 ,平均粒径约为3 6nm。