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1、河南大学 硕士学位论文 液氨介质中金属、氧化物纳米材料的制备及性能研究 姓名：张孟雷 申请学位级别：硕士 专业：材料学 指导教师：孙磊 2011-06 摘 要 I 摘 要 本论文利用液氨-金属纳体系的强还原性在液氨介质中成功制备了不同形貌的金 属、金属氧化物、金属-有机复合纳米材料；对所制备样品进行了结构和形貌表征，研 究了部分样品的光学或磁学性能，在此基础上，提出了碱金属液氨溶液中纳米材料的形 成机理。本论文主要内容包括以下几个方面： 1. 液氨介质中液氨介质中 ZnO 纳米颗粒的制备及其光学性能研究纳米颗粒的制备及其光学性能研究 在金属钠的液氨溶液中还原硝酸锌， 室温下经过在空气中的分离处
2、理过程制备得到 氧化锌纳米颗粒。表面修饰剂十二烷基磺酸钠(SDS)的加入对ZnO纳米颗粒形貌及粒度 有较大影响，通过透射电子显微镜(TEM)、X射线粉末衍射仪(XRD)、傅立叶变换红外光 谱仪(FT-IR)、 紫外可见吸收光谱(UV-vis) 、 荧光光谱(PL)、 热重(TG)和差热分析(DTA) 等表征了所制备ZnO 纳米颗粒的结构、形貌、粒径大小及分布、表面键合性质和热性 能。结果表明，在SDS修饰的情况下可得到平均直径7 nm，长度约18 nm的ZnO纳米棒。 在室温下，用激发波长为325 nm的激光激发测量ZnO和ZnO-SDS样品的PL谱，发现与普 通ZnO相比在液氨中制备的ZnO
3、和SDS修饰的ZnO都未出现近紫外发光，这种现象不太 常见，分析了其成因。 2. 液氨介质中液氨介质中 Fe3O4纳米材料的制备及其磁性能研究纳米材料的制备及其磁性能研究 在金属钠-液氨体系中采用原位表面修饰法制备了 Fe3O4纳米颗粒， 并研究了不同铁 盐反应物对产物生成的影响。用 TEM、XRD、FT-IR 表征了所得产物的形貌和结构。 结果表明，加入适量的表面活性剂聚乙烯吡咯烷酮(PVP)得到的 Fe3O4纳米颗粒粒度分 布比较均匀，粒径大小在 8-17 nm 的范围，平均粒径为 12 nm。采用量子扰动超导探测 器(SQUID)测量了室温下 Fe3O4纳米颗粒的磁性能，结果显示，在金属
4、钠-液氨体系中制 备的 Fe3O4纳米颗粒具有超顺磁性和较高的磁饱和度，在 PVP 保护下制得的 Fe3O4颗粒 的磁饱和度(82.7 emu/g)略低于无修饰剂情况下制得的 Fe3O4颗粒的磁饱和度(90.2 emu/g)，但都接近于块状 Fe3O4的 92 emu/g。 3. 液氨介质中液氨介质中 Pb 纳米带的制备及结构表征纳米带的制备及结构表征 在金属钠的液氨溶液中还原 PbI2得到了 Pb 纳米带，采用 TEM， XRD、FT-IR、X 摘 要 II 射线能量色散仪(EDX)等表征了其形貌和结构。结果表明，所得产物具有 Pb 的立方晶 型结构且为多晶。采用此方法，在反应溶液中未加任何
5、模板的情况下可制备得到沿生长 方向直径分布均匀，平均直径为 40-50 nm 的 Pb 纳米带，FT-IR 结果表明所制备的 Pb 纳米带表面吸附有氨基和羧基基团，提出了碱金属液氨溶液中 Pb 一维纳米结构的形成 机理。 4. 液氨介质中液氨介质中 Sn 纳米颗粒的制备及表征纳米颗粒的制备及表征 在金属钠的液氨溶液中采用原位表面修饰法制备了硬脂酸(St)修饰的金属Sn纳米微 粒。采用 XRD、TEM、FT-IR、TG 等分析手段对产物形貌、结构、表面态以及热性能 进行了表征，结果表明，未加修饰剂情况下制备得到的 Sn 颗粒团聚严重，而用硬脂酸 作修饰剂可以制备得到分散良好的平均粒径约为 20
6、nm 的具有四方晶型晶体结构 Sn 纳 米颗粒。在四球摩擦试验机上考察了所制备样品作为润滑油添加剂的减摩抗磨性能，分 析了其摩擦学性能与样品制备条件的关系。 关键词：液氨，纳米材料，制备，性能 ABSTRACT III ABSTRACT In this dissertation, various metals and metal oxides nanomaterials were prepared by reduction of metal salts in liquid ammonia at the present of sodium metal. Their morphologies an
7、d structures were characterized. The optical and magnetism properties of the as-synthesized particles were investigated. Meanwhile, the formation mechanism of nanomaterials prepared in liquid ammonia at the present of alkali metal was proposed. The main work of this dissertation includes the followi
8、ng parts: 1. Preparation and Optical Properties of ZnO Nanoparticles in Liquid Ammonia. ZnO nanoparticles were prepared by reduction of zinc nitrate hexahydrate in liquid ammonia at the present of sodium metal. It was found that sodium dodecyl sulfonate (SDS) had an obvious effect on the morphology
9、and size distribution of as-prepared ZnO nanoparticles. Morphologies, structure and thermal properties of ZnO nanoparticles were characterized by means of X-ray powder diffraction (XRD), transmission electron microscopy (TEM), Fourier transform infrared (FT-IR), UVVisible (UV-vis), Fluorescence (PL)
10、 spectroscopy, thermogravimetry (TG) and differential thermal analyzer (DTA). The results show that SDS modified ZnO nanoparticles exhibit uniform size distribution and show rod-like shape, the width of the rods is estimated to 7 nm, and the length of rods is 18 nm, The room temperature PL spectrum
11、was performed on a SPEX F212 fl uorescence spectrophotometer with a Xe lamp upon excitation at 325 nm. It was found that the ZnO and SDS modified ZnO nanoparticles prepared in liquid ammonia are no UV emission. This phenomenon is rarely reported. 2. Preparation and Magnetic Properties of Fe3O4 Nanom
12、aterials in Liquid Ammonia. Magnetite (Fe3O4) nanoparticles with a size range of 8-17 nm were prepared by reduction of anhydrous FeCl3in liquid ammonia at the present of sodium metal, the structure and morphologies of as-prepared Fe3O4 nanoparticles were characterized by means of XRD, TEM, FT-IR. Th
13、e results show that quadrangle and hexagon shape and well-dispersed Fe3O4 nanoparticles were syntheized when polyvinylpyrrolidone (PVP) was chosen as the surface modification agent to. the average particles size was 12 nm with a narrow distribution ranging from 8 to 17 nm. The magnetic properties of
14、 Fe3O4 nanoparticles were evaluated on a MPMS XL-7 superconductivity quantum interference device ABSTRACT IV (SQUID) at room temperature. The results show that the as-synthesized Fe3O4 nanoparticles exhibit superparamagnetic behavior and have a high saturation magnetization (Ms) which slightly below
15、 that of bulk Fe3O4 (92 emu/g) 3. Synthesis and Characterization of Pb Nanotapes in Liquid Ammonia. Lead nanotapes were synthesized in liquid ammonia solvent in the presence of sodium metal at low temperature. The process was template free. TEM, oXRD and Energy-dispersive X-ray spectroscopy (EDX) ch
16、aracterizations revealed that the as-prepared Pb nanotapes have average diameters in the range of 40-50 nm, and lengths up to several hundred nanometers, and exhibit cubic crystal structures. FT-IR investigation indicate that the there are plenty of amino and hydroxyl residums on the surface of as-synthesized Pb nanotapes. The formation mechansim of Pb one-dimension nanostructures without template was proposed. 4. Synthesis and Characterization of Sn Nanoparticles Stearate modified Sn nanopart
