中文摘要：

在柠檬酸钠-丙酮-乙醇体系中采用光化学还原法同时还原或连续还原Au（Ⅲ），Pt（Ⅳ）离子，合成了Au核@Pt壳复合纳米粒子。采用X射线光电子能谱（XPS），UV—Vis，透射电镜（TEM）等分析手段对两种方法合成的复合粒子的结构、形貌等进行了对比分析，并对复合粒子核壳复合结构的光化学形成机制进行了讨论。研究表明：两种方法均可合成颗粒比较均匀、具有良好单分散性的Au核@Pt壳复合纳米粒子，其平均粒径5．1～10．2nm；其中，同时还原法制备的复合纳米粒子的平均粒径相对较小是5．1～8．1nm，而当n（Au）：n（Pt）=1：4时，粒径最小，为5．1nm。同时还原和连续还原法所制备的胶体粒子的UV—Vis吸收光谱与Au，Pt简单混合胶体的有明显不同，双金属复合胶体粒子的UV-Vis吸收光谱中Au的特征共振吸收强度明显下降并且蓝移，下降程度远大于其浓度的降低，且随着粒子中Pt元素含量的进一步增加，Au的特征吸收峰最终消失而只体现Pt的吸收光谱，这表明同时还原和连续还原Au（Ⅲ），Pt（Ⅳ）离子所制备的胶体粒子为双金属复合粒子，复合粒子结构中Au元素存在于粒子内部，Pt元素存在于粒子表面，即两种还原方式所制备的双金属复合粒子具有Au核@Pt壳复合结构。

英文摘要：

The Au@ Pt core shell nanoparticles could be synthesized by photochemical reduction, coreduction or continuous reduction of Au（Ⅲ）, and Pt（Ⅳ） ion in sodium citrate-acetone2ethanol system. The structure and morphology of the composite particles were characterized using X-ray photoelectron spectroscopy （XPS）, UV-Vis and transmission electron microscopy （TEM）. And the core- shell composite structure of the composite particles of photochemical formation mechanism was briefly discussed. It was shown that the two ways both could be synthesized relatively uniform particles with good monodispersity of the Au@ Pt core shell nanoparticles and the average particle size was 5.1 - 10.2 nm. Among them, the average particle size of coreduction method was relatively small, and the average size was 5.1 - 8.1 nm. And when n（Au） ： n（Pt） = 1 ： 4, the minimum size was 5.1 nm. Coreduction method and continuous reduction method of the preparation of the colloid particles of UV-Vis absorption spectra with Au, Pt simple hybrid colloids were obviously different. UV-Vis absorption spectra of Au characteristies resonance absorption intensity of double metal composite colloidal particles decreased obviously and had blue shift, the decrease level was much larger than their concentration decrease. And with the further increase of Pt elements content in the particles, the characteristic absorption peak of Au eventually disappeared and only reflected the absorption spectra of Pt. This indicated that preparation of the colloid particles by coreduction or continuous reduction of Au（ Ⅲ）, Pt （Ⅳ） ion acquired bimetal composite particle. And the Au element existed in the composite particles; Pt elements existed in the particle surface. The bimetal composite particles of the two reduction method had Au core@ Pt shell composite structure.