原位液体环境电镜观察银纳米线变纳米管过程  

Evolution of Ag nanowire into Ag-Pt alloy nanotube observed by liquid cell transform electron microscopy

作　　者：齐赫杨 庄春强 QI He-yang;ZHUANG Chun-qiang(Institute of Microstructure and Properties of Advanced Materials,Beijing University of Technology, Beijing 100124, China)

机构地区：[1]北京工业大学固体微结构与性能研究所

出　　处：《电子显微学报》2019年第3期221-227,共7页Journal of Chinese Electron Microscopy Society

基　　金：国家自然科学基金资助项目(No.11874001);北京市自然科学基金资助项目(No.2182008)

摘　　要：利用原位液体透射电镜技术,在透射电子显微镜(TEM)中,实时观察Ag纳米线与H2PtCl6溶液发生化学置换反应的过程。通过原位反应中纳米线的形貌变化,结合扫描透射电子显微镜(STEM)对反应后纳米线进行组分和形貌表征,研究化学置换反应的机制。结果表明,化学置换反应分为两个过程:Pt离子的沉积和Ag原子的溶解。Pt离子持续在纳米线表面沉积,同时纳米线表面部分区域刻蚀形成凹坑,凹坑比纳米线表面的Ag原子溶解速度快,导致刻蚀由凹坑向纳米线内部进行并沿轴向推进,最终使纳米线完全刻蚀为空管。元素分布结果显示,化学置换反应得到的空管为Ag-Pt合金管。Galvanic replacement reaction between silver (Ag) nanowires and an aqueous solution of H 2PtCl 6 has been successfully monitored in real time by using in-situ liquid cell transmission electron microscopy(TEM).The in-situ observations clearly show the morphological evolution of the solid silver nanowires to hollow nanotubes in the course of the reaction. The associated galvanic replacement reaction mechanisms were proposed and analyzed. Pits appear on the surface of the nanowire due to the dissolution of silver atoms at first. The dissolution begins from the pits into the nanowires and continues along the axis results in the formation of nanotubes.The compositions of the nanotubes were characterized by scanning transmission electron microscopy (STEM), which revealed that it contained silver (Ag) and palladium (Pt). The results presented here will serve as an important reference to understand galvanic replacement reaction mechanism.

关 键 词：原位液体透射电镜 化学置换反应机制 元素分布 银铂合金管 

分 类 号：TB383[一般工业技术—材料科学与工程] TG115.215.3[金属学及工艺—物理冶金]