醋酸盐共沉淀法制备锑掺杂二氧化锡(ATO)粉体

在较低的温度下将锡粉和三氧化二锑溶于冰醋酸并通过共沉淀,成功制备了锑掺杂二氧化锡(ATO)纳米粉体.采用XRD、SEM、TEM、N_2等温吸/脱附及粉末电阻率测试仪等对其结构、形貎和导电性进行表征,并研究了锑掺杂浓度对ATO导电性能的影响.结果表明:随着锑掺杂量的增加,ATO粉体电阻率有一最低值,即在锑掺杂浓度为8%时,ATO粉体电阻率可达0.4Ω·cm;ATO粉体的一次粒径约为5nm,其比表面高达85.9m~2/g.     

柔性透明自支撑氧化锡锑电纺纳米纤维膜的制备与表征

以四氯化锡和三氯化锑为前驱体,通过静电纺丝技术制备了柔性透明的自支撑氧化锡锑(ATO)纳米纤维膜.研究结果表明,该柔性ATO纤维膜具有四方相金红石晶体结构,且呈无规的纤维网状分布.当前驱体煅烧温度分别为520℃和700℃时,纤维的平均直径为200和150 nm;组成纤维的颗粒的平均粒径为10和19 nm;可见光透过率为72%和80%;电阻率为5.23和2.20Ω·cm.该自支撑ATO纳米纤维膜还显示出优异的柔韧性,在弯曲500次后其电阻率基本不变.     

掺铕ATO纳米粉体的制备及表征

采用化学共沉淀法制备了掺杂稀土铕的ATO纳米粉体。运用X射线衍射(XRD)、扫描电镜(SEM)等测试方法对ATO粉体进行表征,研究了制备工艺对粉体粒径和导电性能的影响,发现铕的摩尔掺杂比在0.5%～1%之间,600～700℃热处理温度下得到粉体的性能最佳,粉体的电阻率为243Ω.cm,颗粒尺寸为33.6 nm。掺杂前粉体的电阻率和颗粒尺寸分别为181Ω.cm和41.4 nm,掺杂后分别为243Ω.cm和33.6 nm。结果显示掺杂铕会使粉体的电阻率增加,但也能降低粒径,减少团聚。     

锑掺杂二氧化锡(ATO)纳米颗粒:共沸蒸馏干燥法制备及隔热性能

以五水合四氯化锡、三氯化锑为原料,乙醇为溶剂,氨水为沉淀剂,乙酸异戊酯为共沸溶剂,共沸蒸馏干燥前驱体溶胶,650℃煅烧后制备了单分散不同锑掺杂量的掺锑二氧化锡(ATO)纳米颗粒。结果表明,锑含量对颗粒粒径、光电性质具有重要影响,10mol%锑掺杂量时,样品具有最低的电阻率以及最优良的光学性质(最高的可见光透过率与近红外屏蔽效果),电学性质。ATO与聚氨酯复合涂膜玻璃隔热测试表明,涂层薄膜具有优良的隔热效果,能够有效地减小热量的传递与扩散。     

纳米锑掺杂二氧化锡(ATO)水凝胶的水热法制备以及ATO导电薄膜的透明和隔热性能

以醋酸盐共沉淀法制备了锑掺杂二氧化锡(ATO)湿凝胶;将其作为前驱体,在一定温度下经水热法得到ATO水凝胶.考察了前驱体洗涤程度,水热反应温度、p H以及煅烧温度对ATO水凝胶导电性能的影响.进而将酸性条件下得到的ATO水凝胶制备成导电薄膜,考察了其透明和隔热性能.结果表明:前驱体洗涤程度对ATO水凝胶导电性能的影响不大;随着水热反应温度的升高,水凝胶导电性能改善;当凝胶煅烧温度提高到600℃时,ATO样品的电阻率为0.8Ω·cm.此外,ATO导电薄膜的可见光透过率达85%,红外光吸光率为53%,显示出优异的透明和隔热性能.     

锑掺杂二氧化锡（ATO）纳米颗粒：共沸蒸馏干燥法制备及隔热性能

以五水合四氯化锡、三氯化锑为原料,乙醇为溶剂,氨水为沉淀剂,乙酸异戊酯为共沸溶剂,共沸蒸馏干燥前驱体溶胶,650℃煅烧后制备了单分散不同锑掺杂量的掺锑二氧化锡（ATO）纳米颗粒。结果表明,锑含量对颗粒粒径、光电性质具有重要影响,10mol%锑掺杂量时,样品具有最低的电阻率以及最优良的光学性质（最高的可见光透过率与近红外屏蔽效果）,电学性质。ATO与聚氨酯复合涂膜玻璃隔热测试表明,涂层薄膜具有优良的隔热效果,能够有效地减小热量的传递与扩散。     

La1-xCaxMnO3纳米颗粒的制备及氧还原催化性能

本文采用溶胶凝胶法制备了一系列不同Ca含量的钙钛矿型氧化物La1-xCaxMnO3(x=0~0.4)纳米颗粒,X射线粉末衍射及精修、扫描电镜表征显示其相纯度和结晶度高,颗粒平均粒径约40 nm。在0.1 mol.L-1KOH水溶液中进行的氧还原电催化性能测试显示,La0.7Ca0.3MnO3样品催化活性最高,表观电子转移数接近4,还原电流密度与Pt/C催化剂相当,而催化稳定性优于Pt/C。进一步研究了La1-xCaxMnO3样品中Mn价态、晶胞参数的改变对氧还原催化活性的影响,结果表明当x=0.3时,催化剂中Mn处于混合价态,Mn-O键长适中,最有利于电催化反应。     

溶剂热法制备ATO纳米球及其性能研究

以五水四氯化锡和三氯化锑为主要原料,以乙二醇为溶剂,采用溶剂热法合成了锑掺杂氧化锡(ATO)纳米球。用X射线衍射仪和透射电子显微镜对合成的ATO纳米球进行结构表征,用紫外可见分光光度计和低阻抗表面阻抗仪研究其光电性能。结果表明：所合成的ATO均为四方晶型结构,由粒径为5~10 nm的ATO纳米晶聚集成直径为80~120 nm的纳米球,且分散性良好。Sb³⁺掺杂量对ATO纳米球的光、电性能有很大影响,随着Sb³⁺掺杂量的增加其可见光透过率和电导率都呈现先增大后减小的变化关系。在n_Sb/n_Sn比为9∶100时其光电性能达到最佳。     

空穴掺杂对Li1-xCuVO4(x≤0.1)一维自旋链材料光谱性质的影响

采用固相烧结方法合成了部分Li+缺失的一维自旋链材料Li1-xCuVO4(x≤0.1). X射线衍射和Raman光谱分析结果表明, 所得材料属于正交晶系, 具有反尖晶石结构; Li+的缺失并未对材料的长程和短程结构具有明显的影响. X射线光电子能谱(XPS)研究结果表明, 空穴掺杂前后, O离子和V离子的价态并未随Li+缺失而发生改变, 仍然为-2价和+5价. 而Cu离子的2p53d10 L态向高结合能区发生了偏移, 说明在部分Cu2+上出现了空穴, 形成了Cu3+.     

β-Na（Y_（1.5-x-y）Na_（0.5））F_6：Yb_xTm_y纳米颗粒的合成及其上转换发光性质

本文采用水热合成法制备了β-Na（Y1.5-x-yNa0.5）F6：YbxTmy（x=0.2~1.0,y=0.001~0.008）纳米颗粒,并利用X射线粉末衍射仪、透射电子显微镜和F-4600荧光分光光度计表征了其样品的物相、形貌和发光性质.结果表明样品物相为六角相,颗粒平均直径约22nm,并探讨了Yb3＋和Tm3＋掺杂浓度对样品的上转换发光性质的影响,结果表明敏化剂Yb3＋的最佳掺杂浓度为60%,而激活剂Tm3＋的最佳掺杂浓度为0.6%.     

Optical,electrical, and thermal insulation properties of antimony-doped tin oxide nanoparticles prepared by frozen gel method

Antimony doped tin dioxide (ATO) nanoparticles with different Sb doping contents were prepared by freeze-drying the precursor gel and then calcined procedure. The obtained ATO nanoparticles were characterized by X-ray diffraction, scanning electron microscope, optical and electrical techniques. Results indicated that ATO with 10 mol% Sb doping is optimal, with which had the lowest resistivity and highest transmittance in visible region as well as narrow particle size distribution. Thermal insulation properties of ATO/waterborne polyurethane (WPU) films coating on the glass substrates with different thickness were studied on a DIY heat insulating measurement box and showed that the glass coated with ATO/WPU films possessed better heat-insulating effect than empty glass .     

纳米晶Sb掺杂SnO2(ATO)粉体的合成与表征

以Sn粉和Sb₂O₃为原料.采用共沉淀法制备了纳米ATO粉.TG-DSC及FTIR结果表明.450℃以前前驱体已失去全部水分.并完全转化为氧化物.XRD测量结果表明.所得ATO粉具有四方金红石结构.500℃焙烧后粉体的粒径为12nm.随着焙烧温度的升高.粉体的粒径增加.TEM测定结果表明,粉体的分散性很好.团聚很少.粉体的烧结性能良好,950℃时烧结5h即达到理论密度的97.3％.用霍尔系数法测定粉体的导电行为.表明该粉体具有良好的导电性能.     

Sol-Gel Deposited Sb-Doped Tin Oxide Films

The structural, electrical and optical properties of single sol-gel derived antimony-doped tin oxide (ATO) films sintered at 550°C have been measured. The reproducibility of both the preparation and the characterization procedures have been tested by a round-robin test involving eight laboratories within a Concerted European Action (CEA) project. The resistivity measured as a function of Sb content has been obtained by electric and reflectance and transmission measurements. Their differences are discussed in terms of structural and grain boundary effects. An increase of Sb content results in a decrease of the crystallite size (7.0 to 5.4 nm) and a greater influence of the grain boundary.     

Analysis of Antimony Doping in Tin Oxide Thin Films Obtained by the Sol-Gel Method

The antimony doping in SnO₂ thin films prepared by the sol-gel dip-coating method has been studied using two characterization techniques. In order to determine the actual doping level directly in the deposited layers, X-ray photoelectron spectroscopy (XPS) and secondary ion mass spectrometry (SIMS) have been used. We found that this doping level is systematically lower than expected from the starting solutions composition, and that two oxidation states are present: Sb³⁺ and Sb⁵⁺. As the antimony content increases, there is a competition between Sb⁵⁺ and Sb³⁺ species.The SnO₂: Sb thin films have also been observed by transmission electron microscopy (TEM), showing that the measured mean size of crystallites decreases as the Sb content increases in the oxide. No precipitates of either Sn or Sb oxides (other than SnO₂) could be detected.     

Sb掺杂SnO_2(ATO)纳米晶的水热合成和导电性能

以Sn和SbI_3为主要原料，在120-170 ℃温和水热条件下合成了具有导电能力 的Sb掺杂SnO_2(ATO)透明导电纳米粉体，运用FT-IR， XRD， BET， TEM等手段对 粉体的形成过程进行了分析表征。实验结果表明，所合成的纳米ATO粉体均为四方 锡石结构，无其他杂相存在，晶粒大小在4-7nm之间，粉体呈单分散状态。比表面 积在137-184m~2·g~(-1)之间，随水热温度的升高，晶粒长大，比表面积下降，粉 体导电性能提高。该方法对于其他透明导电氧化物纳米粉体的合成具有借鉴意义。     

自掺杂型锑氧化物材料的制备、表征及其对Sr(Ⅱ)的吸附性能

⁹⁰Sr 是核电站放射性废液中需要重点去除的核素之一,水合锑氧化物Sb₂O₅·mH₂O可以在酸性条件下选择性吸附脱除⁹⁰Sr. 本文在以醇为溶剂的无水体系中,以化学性能较稳定且毒性低的SbCl₃为原料,以紫外线照射辅助双氧水氧化及控制水解两步法制备出自掺杂型锑氧化物Sb（Ⅲ）/Sb₂O₅. 文中采用X射线光电子能谱（XPS）、X射线衍射（XRD）和傅里叶变换红外（FTIR）光谱对材料结构进行结构表征,并采用批量实验方法研究不同Sb（Ⅲ）/Sb（total）比例与Sr（Ⅱ）吸附性能的相关性,以及溶液pH 值对Sr（Ⅱ）吸附性能的影响. 实验结果表明：Sb（Ⅲ）可在较大的比例范围内共存于立方烧绿石型Sb₂O₅晶格内,形成良好的固溶体Sb（Ⅲ）/Sb₂O₅;制备过程中通过控制醇溶剂的类型、氧化剂的添加方式以及两步反应温度,可以获得具有不同氧化率,即不同Sb（Ⅲ）/Sb（total）比例的Sb（Ⅲ）/Sb₂O₅材料;其中Sb（Ⅲ）/Sb（total）比例为49.8%的锑氧化物材料吸附性能最好,在纯水体系下对Sr（Ⅱ）的分配系数为6.6×107 mL·g^-1,在pH=3-13 范围内对Sr（Ⅱ）具有良好的吸附性能,并且在本文实验条件下,Sr（Ⅱ）在锑氧化物材料上的吸附更好地符合Langmuir吸附模型.     

EDTA-甘氨酸法制备SmBaCo2O5+δ阴极材料及其性能

采用EDTA-甘氨酸法(EGP)合成了中温固体氧化物燃料电池(IT-SOFC)的阴极材料SmBaCo2O5+δ(SBCO).通过热重-差热分析(TG-DTA),X射线衍射(XRD),透射电镜(TEM),扫描电镜(SEM),直流四极法及交流阻抗技术分析材料的性能.结果表明,初始粉体在850°C煅烧5 h形成钙钛矿结构单相.EGP制备的SBCO粉体颗粒细小、分散性好、粒径分布均匀,其与Sm0.2Ce0.8O1.9(SDC)电解质材料具有良好的高温化学相容性.SBCO的电导率在500-800°C时达到668-382 S cm-1.以SDC为电解质,SBCO为阴极制备对称半电池,其界面结合良好,颗粒连接充分,形成好的三相界面,具有高的阴极催化活性,750°C时阴极极化电阻为0.0688Ωcm2,远低于固相法(SSR)的值,活化能(Ea)为122.21 kJ mol-1.     

Physical Properties of Silica Aerogels Prepared with Polyethoxydisiloxanes

Silica aerogels were made by sol-gel techniques using industrial silicon derivatives (polyethoxydisiloxanes, E-40), followed by supercritical drying with ethanol. The morphology and microstructure of the silica aerogels were investigated by using specific surface area, S_BET, SEM, TEM and the pore size distribution techniques. The thermal conductivity was also measured as a function of air pressure. The results show that the diameter of the silica particles is about 13 nm and the pore size of the silica aerogels is 20–80 nm. The specific surface area of the silica aerogel is about 470 m²/g and the thermal conductivity of the silica aerogel prepared with E-40 is 0.014 w m^–1 K^–1 at room temperature and 1 atm.     

Synthesis and properties of mullite and cordierite aerogels

This work deals with the preparation of aluminosilicate aerogels, especially mullite (3Al₂O₃·2SiO₂) and cordierite (2MgO·2Al₂O₃·5SiO₂) aerogels, from the cohydrolysis of tetraethoxysilane and chelated aluminum-secbutylate; in the case of cordierite magnesium nitrate was added. The influence of various preparation conditions on the aerogel synthesis is described. Crystallization and sintering behavior of mullite aerogels supercritically dried in acetone or alcohol differs from that one of mullite aerogels dried in CO₂. During non-isothermal heat treatment the former show a drastically reduced shrinkage compared to the latter. This behavior can be explained by a phase separation during the high temperature autoclaving process. In cordierite aerogels the crystallization of tetragonal mullite at about 1000°C is observed, while the correspondent xerogels show the crystallization of - and - cordierite between 1000 and 1100°C. On the other hand sintering is promoted in cordierite aerogels, which is due to the content of MgO.     

Preparation of Tin Oxide-Based Metal Oxide Particles

Tin oxide-doped hybrid particles were prepared by a wet chemical process with organic-inorganic (phenyl/silica) hybrid particles in an alcoholic solution. The phenyl/silica hybrid particles, with a diameter of ca. 790 nm were used as a new support material for tin oxide (SnO₂) particles from tin(IV) chloride. The surface of the particles was modified via nitration of aromatic groups in the particles, to promote formation of the tin oxide coating on the particles. The thickness and surface morphology of the tin oxide layer coated on the nitrated-phenyl/silica hybrid particles could be controlled by varying the tin(IV) chloride concentration and reaction time. The size and morphology of the resultant particles were investigated with field emission scanning electron microscopy (FE-SEM) and transmission electron microscopy (TEM). The particles obtained were also characterised by infrared (FTIR) and solid-state ¹³C magic angle spinning nuclear magnetic resonance (¹³C-CP/MAS NMR) spectroscopy. The effect of processing parameters on the crystallinity and structure of the doped hybrids were confirmed by X-ray diffraction (XRD) patterns.