SbxSn1-xO2固溶体系电学性能与导电机制研究

本文报道以均匀共沉淀法制得Sb_xSn_1-xO₂体系半导体气敏材料,研究了固溶体组成与电导的变化规律,并对导电机制进行了讨论。结果表明:x<0.30时均可生成固溶体。微量Sb(x=0.04)的掺入即能提高SnO₂电导一个数量级,在x≤0.04区间电导都呈上升趋势,其后一直到固溶范围内随着X增加,电导反而缓慢下降。根据体系中存在的Sb°_Sn和Sb′_Sn两种缺陷,讨论了其电导变化和导电机制。认为平衡Sb°_Sn+2e′=Sb′_Sn对上述导电机制起决定作用。XPS分析对Sb⁵⁺、Sb³⁺的含量进行了确认,交流阻抗谱的测试结果从另一角度对电导行为加以证实。     

纳米晶Sb掺杂Sn02（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．     

SnO2 纳米棒的氧化还原特性

 利用室温固相反应在 NaCl-KCl 熔盐介质中, 通过焙烧含 SnO2 纳米颗粒前驱体合成了 SnO2 纳米棒, 并采用 X 射线衍射、扫描电镜、透射电镜、选区电子衍射和 X 射线光电子能谱对 SnO2 纳米棒进行了表征. 结果表明, SnO2 纳米棒是表面光滑、结晶完整的金红石结构单晶体, 直径为 10~20 nm, 长度为几百纳米到几个微米. 程序升温还原结果表明, SnO2 纳米棒具有较好的氧化还原性能和催化活性. 探讨了 SnO2 纳米棒的氧化还原机理.     

高比表面积蠕虫状介孔SnO2的合成与表征

 以聚乙二醇 (PEG) 为模板剂, 氯化锡为锡源, 尿素为沉淀剂, 采用水热法合成出高比表面积的蠕虫状介孔四方相金红石型 SnO2. 考察了 PEG 分子量及其浓度、水热温度和焙烧温度对 SnO2 孔结构和形貌的影响. 采用 X 射线衍射、N2 吸附-脱附、透射电镜、红外光谱和紫外-可见光谱等技术对样品进行了表征. 结果表明, 模板剂可被水洗除去, PEG 分子量对介孔 SnO2 的比表面积影响不大, 而 PEG 浓度、水热温度和焙烧温度的影响较大. 在以分子量为 6000 的 PEG 与 Sn 的摩尔比为 0.01 的条件下, 于 120 oC 水热处理 29 h 后可合成出比表面积高达 161 m2/g 和平均孔径为 2.6 nm 的蠕虫状介孔 SnO2. 所制得样品具有较好的紫外光吸收性能, 适宜用作催化剂、载体和气体传感器等.     

SnO_2/中空洋葱状碳纳米复合材料的制备及电化学性能

以炭黑为原料,硝酸铁为催化剂前驱体,氮气气氛下1000℃高温炭化制备了直径为40nm的中空洋葱状碳纳米颗粒(OC).用SnCl2/乙醇溶液浸渍,空气中350℃氧化得到SnO2/OC复合材料.进一步对该复合材料进行酸处理制备OC包覆的SnO2电极材料.采用X射线衍射(XRD)、扫描电镜(SEM)、透射电镜(TEM)和热失重分析(TGA)对OC和SnO2/OC复合材料进行表征;利用恒电流充放电和循环伏安(CV)方法对复合材料作为锂离子电池负极材料的电化学性能进行表征.结果表明:酸处理后的复合材料的循环性能得到明显改善,50次循环后可逆容量保持为446mAh·g-1,OC起到了缓冲SnO2膨胀和阻止团聚的作用.     

Low temperature H2S sensor based on copper oxide/tin dioxide thick film

Nanostructured tin dioxide (SnO2) powders were prepared by a sol-gel dialytic process and and the doping of CuO on it was completed by a deposition-precipitation method. The thick film sensors were fabricated from the CuO/SnO2 polycrystalline powders. Sensing behavior of the sensor was investigated with various gases including CO, H2, NH3, hexane, acetone, ethanol, methanol and H2S in air. The as-synthesized gas sensor had much better response to H2S than to other gases. At the same time, the CuO/SnO2 sensor had enough sensitivity, together with fast response and recovery, to distinguish H2S from those gases at 160 and 210 ℃. Therefore, it might have promising applications in the future.     

Dy改性SnO2 / Sb电催化电极的制备及表征

为改进钛基SnO2／Sb电极的电催化性能，采用高温热氧化法制备了稀土Dy改性钛基SnO2／Sb电极。以苯酚为目标有机物，考察了所制备电极的电催化活性，并采用SEM、EDS、XRD等分析方法表征了电极的形貌、组成及结构。对制备温度和Dy添加量进行了详细的实验研究，确定了适宜的制备条件为热处理温度650℃、Dy添加量1％左右。研究表明，结晶良好的掺杂SnO2晶粒有助于苯酚的快速彻底分解。Dy掺杂后，半径较大的Dy^3 可能取代半径较小的Sn^4 ，导致SnO2晶胞膨胀。引入Dy可提高SnO2晶粒的形核与长大速率之比，使SnO2的平均粒径变小，有利于电极催化性能的改善。但同时Dy掺杂使杂质原子Sb、Dy在电极表层富集，高含量的Dy会降低电极的性能。     

Enhancement of Activity of SnO2-doped In2O3/Al2O3 Catalyst for NO Reduction with Propene in the Presence of H2O and SO2

The selective catalytic reduction of nitrogen oxides by hydrocarbons (HC-SCR) has attracted much attention as an efficient way to remove NO in the presence of excess oxygen1-2. The metal oxides are the most promising catalysts for the SCR of NO because of their high activity and selectivity3-5. In the previous work, the metal oxides such as Ag, Sn, In, Co supported on alumina for NO reduction were investigated6-8, however, the HC-SCR is usually suppressed in the presence of H2O and S…     

纳米抗静电织物整理剂的制备和应用

研究了涤纶用抗静电剂－纳米锑掺杂二氧化锡（ATO）在整理剂中的稳定分散技术，探讨了分散剂的类型，添加量，pH值以及球磨工艺对分散的影响。用分散剂BN，粒子呈单分散状态，直径为20nm，可基本解决ATO在水相团聚现象，当分散剂KH560用量为ATO粉体质量的1％，pH值为9左右，球磨40h时，ATO的分散效果最好。用该抗静电整理剂处理涤纶织物，织的表面电阻从未处理的＞10^12Ω的数量级降低到＜10^10Ω的数量级，洗涤50次，抗静电效果基本不变。     

Forming and Gathering of SnO2 Nanoparticles on External Surface of High Silica TON, MFI and FAU Type Zeolites

Tin dioxide （SnO2） nano-particles were prepared on high silica TON, MFI and FAU type zeolites by impregnation of SnC12 solution and subsequent calcination at 873 K. XRD and SAED were used to characterize the crystalline phase, and TEM was used to characterize the morphology, the particle size and the agglomerative state of the formed nano-materials. The nano-particles, which possess 8 nm, 10-80 nm and 6 nm in size, were found to form on the outer surface of TON, MFI and FAU zeolites, respectively. SnO2 microcapsules and SnOz netlike nanostructure were obtained by decomposition of SnO2-TON and SnO2-MFI in 40% hydrofluoric acid at room temperature. Compared with the nano-particles formed on NaY zeolite, the special morphology and the agglomerative state of SnO2 nanostructures on TON and MFI type zeolites with one and two dimension channel system indicate that the heterogeneous framework, surface structure and property perform important function for forming and growing SnO2 nanostructure on the outer surface of the zeolites.