【作者】 王长顺；

【导师】 施大宁； 阚彩侠；

【作者基本信息】 南京航空航天大学 ， 原子与分子物理， 2010， 硕士

【摘要】 纳米材料是目前材料科学研究的一个热点,其相应发展起来的纳米技术被公认为是21世纪最具有前途的科研领域之一。由于纳米材料的特殊性能与贵金属独特的物理化学性质有机地结合起来使其具有表面效应、体积效应、量子尺寸效应和量子隧道效应,并在光、电、热、磁、催化等领域有着广阔的应用前景而成为纳米材料的一个重要组成部分。同时,由于纳米粒子表现出来的特殊物理化学性质依赖于粒子的尺寸及形貌,因此对纳米粒子实现可控的生长,并实现按照人的意愿设计合成功能材料具有重要的意义。本论文的工作是设计简单有效的合成方法,制备出尺寸和形状可控的金、银纳米结构,并使用场发射扫描电子显微镜(FE-SEM)、透射电子显微镜(TEM)、高分辨透射电镜(HRTEM),原子力显微镜(AFM),X射线衍射仪(XRD)和紫外-可见光光谱仪(UV-Visble)对所得的金、银纳米粒子的结构、形貌和光谱进行表征。本论文的主要成果如下:1、围绕金纳米粒子,主要研究在150oC的溶剂热条件下,从金属前驱液(氯金酸)开始,在表面活性剂(PVP,CTAB)辅助下,利用乙二醇(EG)为溶剂和还原剂,并通过对生长过程的调控达到对纳米粒子形貌进行控制,还原金离子获得了多种形状的金纳米片,提高了纳米粒子的单分散性和反应及晶体生长速率。2、在室温条件下,以水为溶剂,用不同聚合度的PVP(K30,K60和K90)还原氯金酸合成不同形状的单晶金纳米片。提出一种金片从成核到生长成微米级片的生长机制,阐述了金片可能的生长过程。3、在高温条件下,用乙二醇(EG)为溶剂和还原剂,并在PVP作用下还原AgNO3合成Ag的纳米棒(线);另外,利用简单水相法在只有PVP的条件下合成片状纳米结构。4、通过溶胶-凝胶法,在常压条件下制备介孔二氧化硅材料,利用氮气等温吸附对其结构进行评估,并分别对所得介孔材料的比表面积进行测定和孔径分布进行了计算。更多还原

【Abstract】 Nano-material is one of the exciting research subjects on material science in recent years. Nano technology is recognized as one of the 21st century’s most promising research areas. The nanostructural noble metal, together with the unique physical and chemical properties, has surface effect, volume effect, quantum size effect and quantum tunnel effect. It also has been broadly applied in optical, electrical, thermal, magnetic, catalytic and other fields, and become an important component of nano-materials. Meanwhile, it is important to get the shape-controlled noble metal nanoparticles and design the functional materials because their unique physical and chemical properties can be tuned through controlling over the size, shape and morphology of particles. The main content of this dissertation research is to design a simple and effective method to synthesize size- and shape-controlled gold and silver nanostructures. Structures, morphology and spectra characterization were also carried out by field emission scanning electron microscope (FE-SEM), transmission electron microscopy (TEM), high-resolution transmission electron microscopy (HRTEM), atomic force microscope (AFM), X-ray diffraction (XRD) and UV - visible spectrometer (UV-Visble). The main results of this work are listed as follows:1. Through a modified Polyol procee, we mainly studied the synthesis of Au nanoparticles through thermal reduction (150oC) of HAuCl4 precursor in ethylene glycol (EG) solution with the presence of Poly-vinylpyrrolidone (PVP) and Cetyltrimethylammonium bromide (CTAB). By introducing the surfactants (PVP, CTAB) and regulating the growth process, Au nanoparticles of various shapes were obtained. These works provided a demonstration of the use of surfactants to increase the monodisperse of nanoparticles, growth and reaction rate.2. At room temperatures, a simple and modified method was developed for preparing new shapes of Au nanoplates with different degrees of polymerization of PVP (K30, K60 and K90) in the aqueous solution at room temperature. PVP was used as both reducing agent and surfactant. The growth mechanism for Au micro-plates from the nucleation was proposed. Also, the possible growth process of Au nanoplates was described in this thesis.3. The third part of this thesis presented a polyol process for preparing Ag nanorods (or nanowires). Ag nanorods (or nanowires) with the high aspect ratio were synthesized in EG solution by thermal reduction (150oC) of AgNO3 at the presence of PVP used as capping agent. In addition, in terms of regulating the concentration of PVP and changing the temperature and the solution, we can readily access the Ag nanoplates.4. In the fourth part of this thesis, the monolithic porous silica material was prepared by sol-gel method under normal pressure and the obtained structure was examined by Nitrogen sorption isotherms measurement. Additionally, the specific surface area and the distribution of pore size for samples were mensurated and calculated, respectively.更多还原