微波辅助sol-gel法合成Bi_(0.5)Na_(0.5)TiO_(3)粉体及其压电性能研究

采用微波辅助溶胶-凝胶(sol-gel)法制备Bi_(0.5)Na_(0.5)TiO_(3)(BNT)粉体,通过DSC/TG,XRD,SEM,FT-IR等表征方法,分析BNT的反应历程,煅烧温度对BNT成分、晶粒尺寸和压电性能的影响.结果表明,当微波煅烧温度为650℃时,可合成出高纯度BNT粉体(30~120 nm),其居里温度为394℃,d_(33)=7.5 pC/N,ε_(r)=535.58,tanδ=0.29.对比传统马弗炉煅烧sol-gel法,微波辅助sol-gel法有利于提高BNT的介电性能和居里温度,降低介质损耗.

Sol-gel synthesis of nanometer silicon/silicon suboxide/carbon anode material

A stacked Si/SiO_(x)/C composite anode material with carbon-coated structure was prepared by sol-gel method combined with carbothermal reduction using organic silicon.The results of X-ray diffractometry, scanning electron microscopy, and elemental analysis show that the Si/SiO_(x)/C material is a secondary particle with a porous micronanostructure, and the presence of nanometer silicon does not affect the carbothermal reduction and carbon coating.Electrochemical test results indicate that the specific capacity and first coulombic efficiency of SiO_(x)/C composite with nanometer silicon can be increased to 1 946.05 mAh/g and 76.49%,respectively.The reversible specific capacity of Si/SiO_(x)/C material blended with graphite is 749.69 mAh/g after 100 cycles at a current density of 0.1 C,and the capacity retention rate is up to 89.03%.Therefore, the composite has excellent electrochemical cycle stability.

Development of Modified Glasses by Transparent, Functional Hybrid Sol-Gel Nano-Ceramic Coatings, a Comparative Study

This paper concentrates on the development of glasses with self-cleaning surfaces exhibiting high water contact angles. In this study, we prepared super-hydrophobic nano-ceramic coated glass based on titania & silica using simple sol-gel & dip coating methods and studied the best composition of the coatings by altering ratios of titanium tetraisopropoxide (TTIP)/tetraethyl orthosilicate (TEOS) with different homogenizing agents. We characterized the coatings by surface roughness measurement, percentage of optical transmission, static contact angle, near-infrared (NIR) transmission, and diffuse reflectance. The fabrication of coatings on glass substrates played an important role in increasing the water contact angle of about 95° and visible & NIR transmission of about 90%. We compared our modified glass substrate with commercial low emissivity (Low E) glass using X-ray diffraction (XRD) analysis, which showed pure amorphous surface claiming excellent wettability and thus the prepared glass substrate could have a variety of applications in different fields.

Comparative structural and electrochemical properties of mixed P2/O′3-layered sodium nickel manganese oxide prepared by sol-gel and electrospinning methods:Effect of Na-excess content

The effect of Na-excess content in the precursor on the structural and electrochemical performances of sodium nickel manganese oxide(NNMO)prepared by sol-gel and electrospinning methods is investigated in this paper.X-ray diffraction results of the prepared NNMO without adding Na-excess content indicate sodium loss,while the mixed phase of P2/O′3-type layered NNMO presented after adding Na-excess content.Compared with the sol-gel method,the secondary phase of NiO is more suppressed by using the electrospinning method,which is further confirmed by field emission scanning electron microscope images.N_(2) adsorption-desorption isotherms show no remarkably difference in specific surface areas between different preparation methods and Na-excess contents.The analysis of X-ray absorption near edge structure indicates that the oxidation states of Ni and Mn are+2 and+4,respectively.For the electrochemical properties,superior electrochemical performance is observed in the NNMO electrode with a low Na-excess content of 5wt%.The highest specific capacitance is 36.07 F·g^(-1)at0.1 A·g^(-1)in the NNMO electrode prepared by using the sol-gel method.By contrast,the NNMO electrode prepared using the electrospinning method with decreased Na-excess content shows excellent cycling stability of 100%after charge-discharge measurements for 300 cycles.Therefore,controlling the Na excess in the precursor together with the preparation method is important for improving the electrochemical performance of Na-based electrode materials in supercapacitors.

Sol-gel-based porous Ti-doped tungsten oxide films for high-performance dual-band electrochromic smart windows

Dual-band electrochromic smart windows(DESWs)with independent control of the transmittance of near-infrared and visible light show great potential in the application of smart and energy-saving buildings.The current strategy for building DESWs is to screen materials for composite or prepare plasmonic nanocrystal films.These rigorous preparation processes seriously limit the further development of DESWs.Herein,we report a facile and effective sol-gel strategy using a foaming agent to achieve porous Ti-doped tungsten oxide film for the high performance of DESWs.The introduction of foaming agent polyvinylpyrrolidone during the film preparation can increase the specific surface area and free carrier concentration of the films and enhance their independent regulation ability of near-infrared electrochromism.As a result,the optimal film shows excellent dual-band electrochromic properties,including high optical modulation(84.9%at 633 nm and 90.3%at 1200 nm),high coloration efficiency(114.9 cm^(2) C^(-1) at 633 nm and 420.3 cm^(2) C^(-1) at 1200 nm),quick switching time,excellent bistability,and good cycle stability(the transmittance modulation losses at 633 and 1200 nm were 11%and 3.5%respectively after 1000 cycles).A demonstrated DESW fabricated by the sol-gel film showed effective management of heat and light of sunlight.This study represents a significant advance in the preparation of dual-band electrochromic films,which will shed new light on advancing electrochromic technology for future energy-saving smart buildings.

Investigation of UV photosensor properties of Al-doped SnO_(2) thin films deposited by sol-gel dip-coating method

Transparent conducting aluminum doped tin oxide thin films were prepared by sol-gel dip coating method with differ-ent Al concentrations and characterized by X-ray diffraction (XRD), atomic force microscopy (AFM), UV-Vis spectrophotometry and photoconductivity study. The variation observed in the properties of the measured films agrees with a difference in the film's thickness, which decreases when Al concentration augments. X-ray diffraction analysis reveals that all films are polycrystal-line with tetragonal structure, (110) plane being the strongest diffraction peak. The crystallite size calculated by the Debye Scher-rer’s formula decreases from 11.92 to 8.54 nm when Al concentration increases from 0 to 5 wt.%. AFM images showed grains uni-formly distributed in the deposited films. An average transmittance greater than 80% was measured for the films and an en-ergy gap value of about 3.9 eV was deduced from the optical analysis. Finally, the photosensitivity properties like current-voltage characteristics, ION/IOFF ratio, growth and decay time are studied and reported. Also, we have calculated the trap depth energy using the decay portion of the rise and decay curve photocurrent.

Structural evolution-enabled BiFeO3 modulated by strontium doping with enhanced dielectric,optical and superparamagnetic properties by a modified sol-gel method

Multiferroic(BFO)nanoparticles doped with strontium with the general formula Bi1-xSrx FeO3(x=0,0.3,0.5,0.7)were synthesized using a modified sol-gel auto-combustion process.The structural,electrical,optical,and magnetic properties of the samples are discussed.The structural analysis,carried out using the x-ray powder diffraction technique,shows a structural transition from rhombohedral(R-3c)to cubic(Pm-3m)for the doping amount of strontium(Sr)equal to x=0.3.Morphological analysis of the prepared samples were carried out using scanning electron microscopy(SEM).Frequency-dependent dielectric constant and ac conductivity were studied.The doped samples,with improved dielectric properties,can be used to fabricate different optoelectronic devices.Strong dielectric dispersion and broad relaxation were exhibited by all the samples.Cole–Cole plots were employed as an effective tool to study the dispersion parameters,namely,the optical dielectric constant,static dielectric constant,relaxation time,and spreading factor.The activation energy was calculated from the relaxation peaks and Cole–Cole plots,which were found to be compatible with each other.The bandgap of the samples was calculated using diffuse reflectance spectral(DRS)analysis.Sharp and strong photoluminescence in the IR region was observed in the samples,similar to ZnO,which was reported for the first time.Room-temperature and low-temperature magnetization studies point towards the superparamagnetic nature of the samples,with an improvement in magnetic properties with doping.The antiferromagnetic behavior of bulk bismuth ferrite transforms to superparamagnetic in nature for both pure and Sr-substituted bismuth ferrite nanoparticles due to the close dimensions of crystallite size with magnetic domains leading to the break-down of the frustrated spin cycloidal moment.

Application of g-C_(3)N_(4)/sol-gel nanocomposite on AM60B magnesium alloy and investigation of its properties

To protect the AM60B magnesium alloy from corrosion,a sol-gel coating containing hydroxylated g-C_(3)N_(4)nanoplates was applied.The chemical composition of the hydroxylated g-C_(3)N_(4)nanoplates was investigated using X-ray photoelectron spectroscopy(XPS).The hydroxylation process did not affect the crystal size,specific surface area,pore volume,average pore diameter,and thermal stability of the g-C_(3)N_(4)nanoplates.After incorporating pristine and hydroxylated g-C_(3)N_(4)nanoplates,dense sol-gel coatings were obtained.Transmission electron microscopy(TEM)revealed the uniform distribution of the modified g-C_(3)N_(4)in the coating.The average roughness of the coating was also reduced after adding the modified nanoplates due to the decreased aggregation tendency.Electrochemical impedance spectroscopy(EIS)examinations in simulated acid rain revealed a significant improvement in the anticorrosion properties of the sol-gel film after the addition of the modified g-C_(3)N_(4)due to the chemical bonding of the coating to the nanoplates.

Sol-Gel法合成HAP的结晶特征及其对F^-离子吸附性能研究

用ｓｏｌ－ｇｅｌ法合成了具有纳米级尺寸的ＨＡＰ；采用ＸＲＤ，ＩＲ，ＢＥＴ比表面积测定，静、动态吸附等方法研究了不同Ｃａ／Ｐ摩尔比和煅烧温度合成的ＨＡＰ的比表面积、结晶度、晶粒尺寸、晶格缺陷度、热稳定性、平衡吸氟量；探讨了吸氟机理和行为．结果表明：ｓｏｌ－ｇｅｌ法合成的ＨＡＰ在常温、常压、不调ｐＨ的操作条件下，有较大的吸氟能力，且无二次污染，可作为绿色环境材料．

Sol-Gel技术与纳米材料的化学剪裁

本文以ＳｉＯ２纳米材料为实例，阐述了ｓｏｌ－ｇｅｌ化学的基本概念，讨论了ＳｉＯ２纳米材料在结构剪裁和性能调控方面的研究进展和前沿问题，并指出ｓｏｌ－ｇｅｌ技术已经成为实现化学剪裁合成纳米材料的主要手段。

Sol-gel法制备纳米SnO_2气敏材料的研究

用Sol gel法制备SnO2 纳米粒子 ,并用XRD、紫外吸收光谱和激光Raman光谱进行了表征和分析。XRD实验证实了所制备的粒子具有较理想的纳米尺寸 ,其粒径随热退火温度升高而增大 ;Raman光谱表明 ,低温退火时SnO2 纳米材料的氧缺位较大 ;紫外吸收光谱表明退火温度在 30 0～ 5 0 0℃粒径变化很大 ,但光的吸收稳定不变。可望利用这些性质 ,提高SnO2 气敏器件的性能。

纳米掺铁二氧化钛的sol-gel法制备与表征(Ⅰ)热重红外联用分析掺铁二氧化钛凝胶的热分解和晶化特性

本文通过热分析、红外联用和 X射线衍射分析了不同煅烧温度下的纳米掺铁二氧化钛样品，研究了 sol-gel方法制备的纯二氧化钛和掺铁二氧化钛干凝胶的热分解和晶化过程。结果表明，干凝胶有较为明显的两个阶段的热分解。在实验条件下得到的二氧化钛干凝胶粉为无定形，无定形二氧化钛加热晶化过程是一个持续的过程，没有明显的晶化温度。

TiO_2的微波辐射Sol-Gel法制备及其光催化性能

采用微波辐射Sol Gel法在石英砂表面制备负载型TiO2 光催化剂 ,考察不同加热方式 ,微波功率以及微波加热温度对溶胶质量的影响 ,微波加热反应制备的溶胶粒子平均粒径小于常规加热反应制备得到的溶胶粒子 ,微波加热反应适宜条件是微波功率6 0 0W ,反应温度为 90℃ .以苯酚为光催化降解研究对象 ,考察了两种方式制备的负载型TiO2 光催化剂的催化性能 ,实验结果表明微波辐射Sol Gol法制备的负载型TiO2 光催化剂光催化性能也优于常规Sol Gel法制备的负载型TiO2 光催化剂 .

Sol-Gel法制备ZnO压敏陶瓷及其电性

采用溶胶－凝胶（ｓｏｌ－ｇｅｌ）工艺制备ＺｎＯ电压敏陶瓷粉体．探讨其制备的最佳工艺条件：以 Ｚｎ（ＮＯ３）２与 ＮａＯＨ为反应前驱物制取胶体， Ｚｎ２＋浓度控制在 ０．５ｍｏｌ·Ｌ－１以上， ｐＨ值７．５左右，预烧温度３００℃，陶瓷烧结温度１２００℃；制得的压敏电阻的非线性系数α＝２８；研究了稀土Ｌａ２Ｏ３掺杂对该陶瓷电性的影响：低浓度掺杂时，可提高压敏电压，高浓度掺杂时；不呈现压敏特性；对粉体进行了Ｘ射线衍射和透射电镜分析，预烧后得到五元掺杂的ＺｎＯ粉体粒形呈球状，属六方晶系，粒径分布窄，约为４０～８０ｎｍ．

Sol-Gel法制备PLZT系铁电薄膜

介绍了Sol-Gel法,并对近年来Sol-Gel法制备PLZT系铁电薄膜材料的有关研究进行了分析和总结,详细介绍了Sol-Gel法制备PLZT系铁电薄膜材料的各种原料及工艺流程.

新型Sol-Gel技术PZT铁电厚膜的制备及电学性能研究

采用新型ｓｏｌ－ｇｅｌ技术在 Ｐｔ／Ｔｉ／ＳiO2/Si基片上制备出了厚度为 ２～６０μｍ的ＰＺＴ铁 电厚膜材料；研究了ＰＺＴ厚膜的结构及其介电、铁电性能．ＸＲＤ谱分析显示，ＰＺＴ厚膜 呈现出纯钙钛矿相结构，无焦绿石相存在．ＳＥＭ电镜照片显示，ＰＺＴ膜厚均匀一致，无裂 纹、高致密．厚度为５０μｍ的ＰＺＴ厚膜的介电常数为８６０，介电损耗为０.０３，剩余极化强度 是２５μＣ／ｃｍ２．矫顽场是４０ｋＶ／ｃｍ.

多孔氧化铝模板结合sol-gel旋转涂敷法制备PZT纳米管

利用溶胶-凝胶旋转涂敷法在通孔的多孔阳极氧化铝(PAA)模板中制备了锆钛酸铅(PZT)纳米管,研究了溶胶浓度对样品形貌的影响。利用SEM和TEM观察了纳米管阵列和单根纳米管的形貌,采用XRD和EDS图谱分析了纳米管的相结构和化学元素组成。结果表明合成的PZT纳米管结晶良好,具有钙钛矿结构(属于四方晶系);纳米管具有较高的韧性但表面较粗糙,直径和管壁厚度分别约为75和7nm,直径与原始PAA模板的孔径相吻合。在一定范围内调节PZT溶胶的浓度(0.1～0.4mol/L),均能在PAA模板的孔洞中形成PZT多晶纳米管,且组成PZT纳米管的晶粒随着溶胶浓度的增加而变大。

Sol-Gel法制备ZnO∶Al透明导电薄膜

采用Sol Gel工艺在普通载玻片上制备出C轴择优取向性、高可见光透过率以及高电导率的Al3+离子掺杂的ZnO透明导电薄膜。利用SEM、XRD等分析手段对薄膜进行了表征。研究结果表明 :所制备的薄膜为纤锌矿型结构 ,表面平整、致密。通过标准四探针法及UVS透射光谱详细研究了Al3+ 离子掺杂的ZnO薄膜的电学与光学性能。实验发现 ,当Al3+ 离子掺杂浓度为 0 8%时 ,前处理温度为 40 0℃ ,退火温度为 5 5 0℃ ,真空退火温度为 5 5 0℃时 ,薄膜具有较好的导电性 ,电阻率为 3 0 3× 10 - 3Ω·cm ,其在可见光区的透过率超过 80 %。

Sol-Gel法制备NASICON材料及表征

采用溶胶 -凝胶 (Sol-gel)法制得了固体电解质 NASICON材料 .用 X射线衍射、红外光谱、拉曼光谱、核磁共振等方法对材料的结构、组成进行了分析 ,并对材料的电导率进行测量 ,证明材料具有快离子导电特性 .通过对不同烧结温度下材料性质进行比较 ,发现 90 0℃烧结温度下得到的材料具有更好的晶相结构和电导率 .

海藻酸钠水溶液的Sol-Gel转变与凝胶化点的决定

测定了 4个分子量和分子量分布不同、M G不同的海藻酸钠试样在不同浓度下的恒温 (2 5℃ )动态粘弹谱 ,发现 4个试样随溶液浓度升高都会发生溶胶 凝胶 (Sol gel)转变 .实验结果表明 ,该转变符合Winter和Chambon的凝胶化点临界状态的松弛模量G(t)方程 ,由tanδ不依赖于ω的判据求出了海藻酸钠水溶液随浓度变化发生Sol gel转变、出现物理凝胶化的凝胶化点溶液浓度cgel和临界指数n .cgel=7 6wt%～ 8 0wt% ,基本与分子量无关 ;分子量较高的 3个试样的n =0 32～ 0 38,而分子量低的试样的n =0 6 1.该结果表明 ,物理凝胶化主要是由大分子重复单元间的相互作用决定 。