La/Cu比及分散剂对溶胶-凝胶法制备La2CuO4及光学性质的影响

采用溶胶-凝胶法,以硝酸镧和硝酸铜为原料,在不同La/Cu物质的量比条件下合成了La2CuO4粉体。利用X射线衍射仪(XRD)、扫描电子显微镜(SEM)和紫外-可见-近红外光谱(UV-Vis-Nir)对样品的物相组成、显微形貌以及光学性能进行了分析。结果表明,n(La)/n(Cu)比为化学计量比2∶1时,可以制备出单一相的La2CuO4;n(La)/n(Cu)<2∶1时,产物含有CuO杂质相;n(La)/n(Cu)>2∶1时,含有La2O3杂质相。根据UV-Vis-Nir光谱分析,n(La)/n(Cu)为2∶1,所得La2CuO4的光学带隙为1.37eV,杂质相的产生使光学带隙减小。以抗坏血酸、葡萄糖为分散剂,有较好的分散效果,聚乙二醇作为分散剂时,出现团聚现象,相应的光学带隙分别为1.39、1.41和1.33eV。     

LaNiO3凝胶薄膜微细图形的制备

采用溶胶-凝胶工艺,以Ni(Ac)_2、La(NO_3)_3为前驱原料,以乙醇和乙二醇甲醚为溶剂,以丙烯酸为稳定剂,乙酰丙酮(AcAc)为化学修饰剂制备了感光性LNO溶胶。通过其溶胶的紫外和红外吸收光谱研究了感光性LNO溶胶的紫外感光机理,并运用溶胶-凝胶直接感光法制备出LNO薄膜的微细图形。     

乙二醇溶剂热合成自组装SrTiO3片状纳米结构及其光催化性能

以钛酸四正丁酯((C4H9O)4Ti)水解沉淀的钛羟基氧化物和硝酸锶(Sr(NO3)2)为反应原料,以氢氧化钾(KOH)为矿化剂,以乙二醇((HOCH2)2)为溶剂,经200℃溶剂热反应得到了由纳米颗粒自组装形成的SrTiO3片状纳米结构。分别用XRD、SEM、TEM表征SrTiO3粉体的物相结构和微观形貌。通过光催化降解罗丹明B(RhB)对比研究了乙二醇溶剂热合成的纳米颗粒自组装SrTiO3片状纳米结构和水热合成的SrTiO3粉体的光催化性能,结果表明,乙二醇溶剂热合成的SrTiO3自组装片状纳米结构具有更加优异的光催化性能。     

溶剂体系对c轴择优取向ZnO薄膜结构和光学性质的影响

以无水乙醇、乙二醇甲醚、乙二醇甲醚/乙醇混合溶液(1∶1)为溶剂体系,采用溶胶-凝胶法制备了ZnO透明薄膜,并利用场发射扫描电镜、X射线衍射和反射光谱仪等研究了溶剂体系对薄膜组成、结构和光学性能的影响。结果表明,3种溶剂所制备的ZnO薄膜均为六方纤锌矿型结构,具有c轴择优取向;以乙二醇单甲醚/乙醇混合溶液(1∶1)为溶剂制备的ZnO薄膜平整、致密,在可见光区域透光率达到90%左右,禁带宽度为3.25eV,具备制作薄膜太阳能电池透明导电电极材料的应用价值。     

Na2O-B2O3-SiO2玻璃的制备及其三阶非线性的研究

以正硅酸乙酯、硼酸和乙醇钠为先驱体,分别以无水乙醇、乙二醇甲醚和无水乙醇为溶剂,采用溶胶-凝胶结合气氛控制的方法制备了Na2O-B2O3-SiO2玻璃。通过热重-差热分析、红外光谱、X射线粉末衍射等手段对凝胶的热分解机制、玻璃的形成过程和物相结构进行了表征。结果表明,在600℃时制得了透亮密实的玻璃。采用紫外-可见吸收光谱和Z-扫描技术对获得的玻璃的光学特性进行了研究,结果表明该玻璃具有良好的光透过率,且其三阶非线性极化率为1.49×10-19 m2/V2。     

纳米TiO2的制备及其性能研究

以钛酸丁酯(TBOT)为前驱物、乙醇(EtOH)为溶剂、水为反应剂、盐酸为催化剂,采用溶胶-凝胶技术制备了无色透明TiO2溶胶和纳米TiO2粉体.运用正交试验设计和极差分析,优化了制备无色透明TiO2溶胶的工艺.利用紫外-可见光谱(UV-Vis)分析了溶胶的光学性能,傅里叶变换红外光谱(FT-IR)表征了凝胶的分子结构...     

溶胶凝胶-自燃烧法合成La 9.33Si 6O26超细粉体

用柠檬酸和乙二醇做络合剂和燃料,硝酸盐做氧化剂,用氨水调节溶胶pH值,通过溶胶凝胶-自燃烧法一步合成了可用于固体氧化物燃料电池(SOFC)的新型固体电解质La9.33Si6O26.用XRD、TEM等分析方法对合成粉体进行了物相测定与形貌观察,并初步考察了粉体的烧结性能.结果表明:通过工艺参数的有效设计,溶胶-凝胶和自燃烧过程可以在短时间内达到合成所需要的高温,一步合成粒径约为150～300 nm的单相La9.33Si6O26超细粉体,其烧结温度比固相法制备的粉体的烧结温度约低200℃.     

花状CuInS_2微晶的溶剂热合成及表征

以CuCl2.2H2O为铜源,InCl3为铟源,硫脲(Tu)为硫源,分别以N,N二甲基甲酰胺(N,N-dimethylformamide,DMF)、乙二醇、乙醇、聚乙二醇-300为溶剂在200℃下反应12h合成花状CuInS2微晶。用X射线粉末衍射仪、X射线光电子能谱、场发射扫描电子显微镜对粉体的结构、形貌、相组分进行表征。研究表明:以DMF、乙二醇、乙醇、聚乙二醇-300为溶剂均能得到由厚度为100~200nm的纳米片组成的花状CuInS2微晶。并对其形成机理进行探讨。     

改进水热法合成ZnO的形貌调控及光学性质

以Zn(NO3)2·6H2O为初始原料,以乙二醇甲醚作溶剂,乙醇胺为沉淀剂,采用水热法制备了不同形貌的ZnO粉体。通过X射线衍射、扫描电镜、荧光光谱等测试手段对不同形貌的ZnO粒子进行了表征。SEM结果表明调节反应物浓度和反应温度能够控制ZnO的尺寸和形貌。荧光光谱测试表明ZnO的紫外发射峰位为399nm,随反应温度升高而发生宽化和红移,而绿光发射峰在453~493nm之间分裂为4个次级峰。     

La9(SiO4)6-x(VO4)xO1.5+0.5x的合成及其导电性能的研究

利用溶胶-凝胶法低温合成了钒掺杂硅酸盐氧基磷灰石La9(SiO4)6-x(VO4)xO1.5+0.5x(x=0、0.5和1),经XRD表征所得产品为磷灰石相.以电化学阻抗谱研究了其导电性能,V的掺杂使电导率大大提高,700℃时La9(SiO4)5(VO4)O2电导率为5.23×10-3S·cm-1,与未掺杂V的La9(SiO4)6O1.5相比提高了5倍.氧分压Po2=105～1Pa时,La9(SiO4)6O1.5的电导率不改变,而La9(SiO4)5(VO4)O2的电导率则随着氧分压的降低而稍有增加,表明钒的掺杂在体系中引入n型电子导电.     

Preparation of macroporous and mesoporous TiO2 film with various solvents

To investigate the effects of solvents on the microstructure, porous TiO₂ films have been prepared by sol-gel method using hydroxypropyl cellulose as the additive. Ethylene glycol monomethyl ether, propylene glycol monomethyl ether, ethanol, and the mixed solution of half ethylene glycol monomethyl ether and half ethanol were chosen as the solvents. Infrared spectra, scanning electron microscope micrographs, and X-ray diffraction patterns have been studied to characterize the microstructure of the sol and film samples. The results showed that mesoporous TiO₂ films with the pore size around 20 nm, 10 nm and 6 nm were obtained when propylene glycol monomethyl ether, the mixed solution of half ethylene glycol monomethyl ether and half ethanol, and ethanol were used as solvent, respectively. It was found that COC group in the solvent was beneficial to enlarge the pore size, because the oxygen bridge in the COC groups could be pulled out and act with titanoxane polymers. When ethylene glycol monomethyl ether was used as the solvent, macroporous TiO₂ film with pore size around 200 nm was obtained. This can be ascribed to the high enough concentration of effective COC groups of the solvent.     

液位沉降法制备AZO薄膜及其光电性能研究

以二水乙酸锌为原料,乙二醇甲醚和无水乙醇为溶剂,乙醇胺为稳定剂,六水合氯化铝为掺杂剂,合成AZO前驱液,采用自制的液位沉降装置在玻璃衬底上制备AZO薄膜,用XRD、UV—Vis、AFM、四探针、台阶仪等方法对薄膜进行表征,结果表明,应用液位沉降法制备AZO薄膜的优化条件为：溶胶浓度为0．5mol／L、Al3＋／Zn2＋浓度比为4at％、干燥温度100℃、干燥时间10min、预处理温度450℃、镀膜层数为20层、液位沉降速度为5cm／min、预处理时间为10min、550℃退火2h,得到薄膜透光率为88％,方块电阻为536Ω／□。     

Influence of Ethylene Glycol on the Formation of Calcium Phosphate Nanocrystals

A synthesis route of using calcium hydroxide Ca(OH)2 with ethylene glycol solvent and orthophosphoric acid (H3PO4) as reagents is described. Three ratios of ethylene glycol to distilled water 1:0, 1:1 and 0:1 are used as diluting media for Ca(OH)2. Crystals of different morphology and composition are formed under weak alkaline circumstance at pH 7.0～8.0. Acicular calcium phosphate nanocrystals are prepared in pure ethylene glycol while rod-like calcium phosphate nanocrystals form in pure distilled water. The nanograde size of the former is smaller than that of the latter. Calcium-deficient apatite (CDAP) is obtained with a Ca/P molar ratio of 1.66. Therefore, it was deduced that the usage of ethylene glycol solvent could influence the formation of calcium phosphate crystal lattice.     

Dip coated 12CaO·7Al2O3 thin films through sol-gel process using metal alkoxide

Transparent nanostructured 12CaO·7Al₂O₃ thin films with cubic structure have been prepared on soda lime glass substrates via the sol-gel dip coating using the precursor sol solution at low temperature. The structural, compositional, morphological and optical properties of the 12CaO·7Al₂O₃ films and powder were studied using X-ray diffractometry (XRD), X-ray photoelectron spectroscopy, scanning electron microscopy (SEM) and atomic force microscopy. Optical properties of 12CaO·7Al₂O₃ films have been investigated using UV-visible spectroscopy. Two different precursor sols were prepared using calcium-2-ethyl hexonate and aluminium isopropoxide as precursor materials in isopropanol and ethylene glycol monomethyl ether solvents. Dip coated gel like films were dried at 120 °C for 15 min and subsequently heat-treated at 450 °C for 1 h in air atmosphere. The influence of films thickness and optical transparency with use of different solvent and sol concentration on microstructure of the films were established. In addition, XRD patterns revealed that 12CaO·7Al₂O₃ films have been composed of cubic phase. SEM observations exhibited that the films structure becomes more homogeneous using isopropanol as compared to ethylene glycol monomethyl ether solvent. The 12CaO·7Al₂O₃ films prepared using 2 (wt.%) sol in isopropanol had high transparency nearly 88% in wide visible range with maximum of 90% at 600 nm wavelength.     

Synthesis of c-axis preferred orientation ZnO:Al transparent conductive thin films using a novel solvent method

Transparent aluminum doped zinc oxide (ZnO:Al, AZO) conducting thin films with a high-preferential c-axis orientation were synthesized using a new sol-gel formula. The films were deposited using a spin-coating route onto borosilicate glass substrates. We used propylene glycol methyl ether (PGME) as the solvent in place of ethylene glycol monomethyl ether (EGME), which is commonly used because it is easier to deposit onto the substrates. PGME is also superior in terms of health and safety. PGME solvent does not need to settle for several days before use and can be spin-coated as soon as the raw material and solvent are mixed. The effects of this novel solvent on the structural, morphological, electrical and optical properties are discussed using XRD, SEM, a four-point probe and UV-VIS spectrophotometry. It was found that the films produced with PGME showed a high-preferential c-axis orientation and compact microstructure in comparison films produced using EGME. The electrical resistivity of AZO thin films produced with PGME solvent was lowered to 3.474 × 10^− 3Ω cm after annealing in 95 N₂/5H₂ atmosphere. In addition, the optical transmittances of AZO thin films on glass plates were higher than 90% in the visible wavelength region.     

Effect of ethylene glycol monomethyl ether ratio in mixed solvent on surface morphology,wettability and photocatalytic properties of ZnO thin films

Zinc oxide (ZnO) thin films with different ethylene glycol monomethyl ether (EGME) ratio were prepared on Si substrates using a two-step process. The results show that they possess a polycrystalline hexagonal wurtzite crystal structure. The topography of the ZnO thin films evolves from nanoparticles to hexagonal nanorods with the decrease of EGME content. The photoluminescence spectra consist of a near-band-edge emission and two visible emissions. The optical band gap energy decreases first and then increases with the increase of EGME ratio in mixed solvent, the broadening of the optical band gap can be explained by Moss–Burstein effect. The wetting behavior of all the samples can switch from hydrophobicity to hydrophilicity through UV illumination. The degradation efficiency of the thin films increases with decreasing EGME content, photocatalytic reaction mechanism of the ZnO thin films is discussed in detail.     

增韧双马来酰亚胺树脂及其玻璃布层压板的制备与性能

以糠醇,六次甲基二异氰酸酯和二苯甲烷双马来酰亚胺通过Ｄｉｅｌｓ－Ａｌｄｅｒ反应合成了含有氨酯宾新型双马来酰亚胺ＢＭＵ－Ｈ．用ＢＭＵ－Ｈ作为二苯甲烷双马来酰亚胺ＢＭＩ的增韧改性剂,ＢＭＵ－Ｈ与二苯甲烷双马来酰亚胺不同比例简单混合得到增韧改性的新型双马来酰亚胺树脂。     

新型双马来酰亚胺基体树脂及其玻璃布层压板的制备与性能

以糠醇、甲苯二异氰酸酯（ＴＤＩ－２０／８０）和二苯甲烷双马来酰亚胺（ＢＭＩ）为原料,采用由Ｄｉｅｌｓ－Ａｌｄｅｒ加成反应合成的含有氨酯键的新型双马来酞亚胺ＢＭＵ－Ｔ作为二苯甲烷双马来酰亚肢的增韧改性剂．通过ＢＭＵ－Ｔ与二苯甲烷双马来酰亚胺以不同比例简单混合得到增韧改性的新型双马来酰亚胺基体树脂;用丙酮和乙二醇单甲醚作为混合溶剂制备了贮存稳定性能优良的树脂溶液和玻璃布预浸料。压制得到的玻璃布层压板具有良好的力学性能和电气性能．１５５℃下的弯曲强度保留率可以达到９０％以上,而且对甲苯、饱和氯化钠水溶液及１０％的盐酸具有很好的耐腐蚀性能。     

Structural,electrical, and rheological properties of palladium/silver bimetallic nanoparticles prepared by conventional and ultrasonic-assisted reduction methods

Polyvinylpyrrolidone stabilized Pd/Ag bimetallic nanoparticles (NPs) with average particle sizes of 9 and 6 nm were synthesized by simultaneous reduction in the presence and absence of ultrasound waves, respectively. The prepared NPs were characterized by six methods including X-ray diffraction (XRD), transmission electron microscopy (TEM), high resolution-TEM (HRTEM), UV–vis spectroscopy, scanning tunneling microscopy (STM), and energy dispersive X-ray (EDX) analysis. The rheological properties of Pd/Ag NPs in ethylene glycol as a base fluid with various mass fractions of NPs from 2% to 5% at different temperatures were studied experimentally and theoretically. The experimental results showed that viscosity of Pd/Ag NPs in ethylene glycol increases with increasing particle mass fraction and decreases with increasing temperature. A maximum of 31.58% increase in viscosity of ethylene glycol at 20 °C was observed when 5% Pd/Ag NPs was added. Measurement of the electrical conductivity of nanofluids of Pd/Ag bimetallic NPs in distilled water at different mass fractions and temperatures was performed. A 3841% increase in electrical conductivity of distilled water at 25 °C was observed when 1% Pd/Ag NPs was added. Both the rheological and electrical properties of Pd/Ag bimetallic NPs were measured in ethylene glycol and distilled water, respectively for the first time.     

Speeds of Sound and Isentropic Compressibilities of n-Alkoxyethanols and Polyethers with Propylamine at 298.15 K

The speeds of sound (u) have been measured at 298.15 K and atmospheric pressure, as a function of composition for seven binary liquid mixtures of propylamine (CH₃CH₂CH₂NH₂, PA) + ethylene glycol monomethyl ether (2-methoxyethenol, CH₃(OC₂H₄)OH, EGMME); + diethylene glycol monomethyl ether [{2-(2-methoxyethoxy)ethanol}, CH₃(OC₂H₄)₂OH, Di-EGMME]; + triethylene glycol monomethyl ether [{2-(2-(2-methoxyethoxy)ethoxy) ethanol}, CH₃(OC₂H₄)₃OH, Tri-EGMME]; + diethylene glycol monoethyl ether [{2-(2-ethoxyethoxy)ethanol}, C₂H₅(OC₂H₄)₂OH, Di-EGMEE]; + diethylene glycol monobutyl ether [{2-(2-butoxyethoxy) ethanol}, C₄H₉(OC₂H₄)₂OH, Di-EGMBE]; + diethylene glycol diethyl ether [bis(2-ethoxyethyl)ether, C₂H₅ (OC₂H₄)₂ OC₂H₅, DEGDEE]; and + diethylene glycol dibutyl ether [bis(2-butoxyethyl) ether, C₄H₉(OC₂H₄)₂OC₄ H₉; DEGDBE] using a Nusonic velocimeter based on the sing–around technique. These values have been combined with densities derived from excess molar volumes to obtain estimates of the molar isentropic compressibility K _S,m, and their excess values . The values are shown to be negative for all mixtures over the entire composition range. The deviations u ^D of the speeds of sound from the values calculated for ideal mixtures have been obtained for all estimated values of mole fraction x₁. The change of and u ^D with composition and the number of –OC₂H₄ – units in the alkoxyethanol are discussed with a view to understand some of the molecular interactions present in alkoxyethanol – propylamine mixtures.Also, theoretical values of the molar isentropic compressibility of K _S,m and of the speed of sound u ^D have been calculated using the Prigogine-Flory-Patterson (PFP) theory with the van der Waals (vdW) potential energy model, and the results have been compared with experimental values.