摘要贵金属纳米材料具有优异的光学性质和稳定的物化性能，使其在生物、医疗、 催化、材料等领域具有广泛的应用前景。而贵金属纳米粒子的性能和它所处的环境， 自身的形态、尺寸与结构等息息相关。近年来，分子手性的重要性也逐渐被人们所 认知，具有手性的贵金属纳米粒子在手性识别和手性催化等领域具有潜在的应用， 是手性研究的一个重要方向。82612

核壳纳米结构材料具有优良的性质，本文采用柠檬酸钠还原法制备金银核壳纳 米粒子，以柠檬酸钠作为稳定剂及还原剂，在 100 oC 回流温度下制备单分散的纳米 金溶胶，并以制备的金溶胶为核，在 100 oC 加热回流下，加入柠檬酸钠和硝酸银， 使银纳米粒子包裹住金核，从而制得金银核壳纳米粒子。对制备的金银核壳结构的 纳米粒子进行表面修饰，使用具有手性的脱氧胆酸钠和半胱氨酸为修饰剂和手性诱 导剂，考察对制备的核壳结构纳米粒子手性的影响。

以液相化学还原法制备稳定的银纳米粒子，并且以六（乙二醇）二硫为刻蚀剂， 通过刻蚀银纳米粒子制备了具有手性的银纳米团簇，考察了六（乙二醇）二硫的加 入量、溶液的 pH 值、陈化时间等对银纳米团簇手性的影响。研究发现，陈化对于银 纳米粒子手性具有重要影响，未经过陈化处理的银纳米粒子基本上没有手性信号， 而经过陈化处理的银纳米粒子却出现了不同程度的信号。在陈化过程中刻蚀剂六（乙 二醇）二硫逐渐将银纳米粒子碎解为尺寸很小的银纳米团簇。并且溶液的 pH 值会影 响生成的银纳米团簇的 CD 信号强度，低 pH 值条件下制备的银纳米团簇具有很强的 CD 信号，溶液 pH 值降低引起脱氧胆酸钠质子化，生成尺寸较大的聚集体，有效的 保护了生成的银纳米团簇，从而具有较强的手性性能。

毕业论文关键词：金银核壳纳米粒子；银纳米粒子；手性；液相化学还原

Abstract Noble metal nanomaterials have broad application prospects in the fields of biology, medicine, catalysis, materials and so on due to their excellent optical properties and stable physical and chemical properties。 The properties of noble metal nanoparticles are closely related with their environment, their morphology, size and structure。 In recent years, the importance of chiral molecules is gradually perceived by people。 Chiral noble metal nanoparticles have potential applications in chiral recognition and chiral catalysis, and it is an important direction for the study of chirality。

Core-shell nanostructure materials have excellent properties。 In this paper, the conventional citrate reduction method was utilized for the preparation core-shell nanoparticles of gold and silver。 Using sodium citrate as stabilizer and reducing agent, the monodisperse gold nanocolloids were prepared at 100 oC reflux temperature。 Au/Ag core-shell nanoparticles were prepared with Au nanoparticles as the cores by the addition of sodium citrate and silver nitrate at 100 oC reflux temperature。 The prepared Au/Ag core-shell structure nanoparticles were surface modified by chiral molecules sodium deoxycholate and cysteine as modifiers and chiral inducers and their chiral properties were investigated。

By chemical reduction in liquid phase preparation of stable silver nanoparticles and hexa(ethylene glycol) dithiol as etchant, which etches silver nanoparticles into chiral silver nanoclusters。 The effects of hexa(ethylene glycol) dithiol sulfur adding amount, solution pH value and the aging time on the chiralities of the silver nanoclusters were investigated。 The study found that aging has an important impact on the chirality of silver nanoparticles。 Silver nanoparticles without aging treatment show no chiral signal, but samples after aging treatment to some extent have chiral signals。 During the aging process, the etchant hexa(ethylene glycol) dithiol gradually etches the small-sized silver nanoparticles into nanoclusters。 The pH values of the solution also affect the CD signal strength of the produced silver nanoclusters and silver nanoclusters prepared at low pH value have strong CD signals。 The silver nanoclusters with strong chiral properties are because reducing   the