【摘要】 在已制备好的Au纳米粒子表面 ,通过化学还原的方法沉积生长Ag包覆层 .通过控制Au ,Ag的比例 ,制备了粒度均匀且粒径可控的Au/Ag核 -壳结构纳米粒子 .利用UV vis吸收光谱和透射电子显微镜 (TEM)对Au,Ag摩尔比为 1∶10的复合纳米粒子的光学性质和形态进行随时监测 ,直接观察了核 -壳结构纳米粒子的生长过程 :一部分Ag+ 在Au核表面还原生长 ,溶液中其余Ag+ 还原形成银的纳米团簇向粒子表面的继续沉积生长 ,壳层增厚更多还原

【Abstract】 Core-shell Au/Ag nanoparticles were prepared by deposition o f Ag through chemical reduction in the presence of preformed Au nanoparticles. B y changing the molar ratio of Ag to Au, the thickness of the shell and thus the size of bimetallic particles could be controlled in convenient way. In this work , uniformly-sized core-shell Au/Ag nanoparticles were prepared with large amou nts of depositing metals until the molar ratio of Ag to Au reaches 1∶10. The fo rmation mechanism of the “core-shell” type nanoparticles was studied by UV- vis spectra, transmission electron microscopy (TEM), etc. A small moiety of silver ions on the surface of gold seeds is reduced. The remaining silver ions i n solution are reduced to form nanoclusters. The clusters are deposited on the s urface of the particles and the thickness of silver shells increased.更多还原