【作者】 程敬泉；

【导师】 姚素薇；

【作者基本信息】 天津大学 ， 应用化学， 2005， 博士

【摘要】 纳米材料的制备是纳米科技研究的重要组成部分,纳米粒子组装则是用化学方法制备纳米结构的重要手段,它是将纳米粒子形成组织化、有序化结构的一种有效手段。本文采用超声波与化学、电化学方法相结合的制备技术,得到了Ag、Au纳米材料,并初步研究了Au纳米粒子的自组装。利用TEM、SAED、SEM、SPM、XRD、UV-vis及电化学工作站等现代测试技术对材料的尺寸、形状、结构、吸收光谱及制备机理进行了较为系统的研究。以AgNO₃为前驱物,PVP为保护剂,KBH₄和N₂H₄·H₂O分别为还原剂,在超声场作用下,制备了稳定的银胶体。研究了超声场分布、超声作用时间、超声功率等因素对银纳米粒子形貌的影响。在驻波场下有利于六边形银纳米颗粒的形成,而扩散场则有利于单分散球形银纳米颗粒的形成。超声作用时间增长及功率增大,均使银纳米颗粒变小,银胶体稳定性增强。扩散场下作用180min所制得的银胶体主要以单分散的球形纳米颗粒形式存在,平均粒径约为20nm,放置数周后仍末出现聚沉物。改变还原剂的种类,可以制备出球形或类球形、六边形等不同形貌的银纳米颗粒。在超声场作用下,以氯金酸为前驱物,经柠檬酸钠和单宁酸还原,首次制备了具有较大长径比的纺锤形金纳米材料。超声场分布和超声功率对金纳米粒子形貌影响较大,驻波场下制备的金粒子为纺锤形,而且随超声功率的增大,金粒子的平均长径比减小;而在扩散场中得到单分散的球形金纳米颗粒,平均晶粒尺寸为25nm。目前用来进行纳米组装研究的金胶体多通过两相法和柠檬酸盐还原法制得,本文将超声场引入金纳米粒子制备工艺中,考察了超声场下制备的金粒子在云母、硅片及玻璃基底上的组装行为。以硝酸银为前驱物,EDTA和胱氨酸为络合剂,采用超声电沉积方法制备了不同形貌的银纳米材料,考察了超声功率及作用时间对银粒子形貌及吸收光谱的影响,并通过测试阴极极化曲线研究分析了超声场对电化学法制备银纳米粒子的影响。更多还原

【Abstract】 Preparation of nano-structured materials is one important component parts of nano-scale science and technology research. The structure prepared by nano-particles assembly has witnessed tremendous growth from expectation to nano-structured materials by chemical method.The purposes of this dissertation are to study the preparation of Ag nano-particles, Au nano-particles and Au assembly membrane by sono-chemical and sono-electrochemical preparation technique. By means of modern characterization methods with TEM, SAED, SEM, SPM, XRD and UV-vis, the influencing factors, growth mechanism and related properties of these metal nano-materials have been investigated.In the ultrasonic field, stable Silver colloids have been produced by the reduction of AgNO₃ with the protection of PVP using KBH4 and N2H4·H2O as reductants. For the first time, the main effective factors on morphology of silver nano-particles, such as distribution of the ultrasonic field, ultrasonic time and ultrasonic power, are studied. The results indicate that the factors such as distribution of the ultrasonic field, ultrasonic time, ultrasonic power and the species of reductant make great impact on morphology of silver nano-particles. The size of silver nano-particles decreases with the ultrasonic power and ultrasonic time increasing. Ag nano-particles prepared in the standing wave field grow following a certain direction. The standing wave field is propitious to form hexagonal and spherical-like silver nano-particles. Well-dispersed spherical silver nano-particles are easily synthesized in the diffusion field. The stability of silver colloid becomes better after ultrasonic treatment. For example, precipitation is not found after several weeks deposited of silver colloid with ultrasonic treatment 180min. The silver nanoparticles are big spherical-like and hexagonal without ultrasonic. Well-dispersed spherical silver particles with the mean size of about 20nm have been prepared after ultrasonic treatment. Spherical, spherical-like and hexagonal silver nano-particles are prepared with the change of reductants.Stable and well-dispersed gold colloids have been prepared by the reduction of HAuCl4 with sodium citrate and tannin as reductants in the ultrasonic field. The spindle gold particles were prepared firstly in the standing wave field. The resultsindicate that ultrasonic field distribution and power influence morphology of gold nano-particles strongly. The average aspect ratio decreases with the ultrasonic power increase. Mono-dispersed spherical gold nano-particles with the size of 25nm are synthesized in the diffusion wave field.In the present time, gold colloids prepared by the two phases method and the citrate deoxidization method can usually be used to assembly nano-structure materials. The ultrasound field was firstly introduced into the preparation of Au nano-particles. The assembly of Au nano-particles on different substrate such as mica, Si and glass were investigatedShaped silver nano-particles with sphere, wire and dendrite were prepared by sono-electrochemical deposition from an aqueous solution of AgNO3 in the presence of ethylenediaminetetraacetic acid disodium salt （EDTA） and polyvinylpyrrolidone （PVP）. The main effective factors on morphology of silver nano-particles and absorption spectrum, such as ultrasonic time and ultrasonic power, are studied. The effect of supersonic field on silver nano-particles prepared by sono-electrochemistry method was firstly discussed with the static polarization curves.更多还原