State Key Laboratory of Polymer Physics and Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022, People's Republic of China.
Langmuir. 2013 Jun 4;29(22):6722-7. doi: 10.1021/la400728k. Epub 2013 May 20.
Ag nanoparticles of ~20 nm size and rather uniform size distribution were synthesized in polyelectrolyte multilayers (PEMs) via an ion-exchange/reduction process in two stages (seeding and growth), which were used as sacrificial templates to fabricate Ag-Au bimetallic hollow nanoparticles via galvanic replacement reaction. The reaction process was monitored by UV-vis spectroscopy. The morphology and structure of the nanoparticles were characterized by transmission electron microscopy (TEM) and energy dispersive X-ray spectroscopy, which confirmed the formation of hollow Ag-Au bimetallic nanoparticles. UV-vis absorbance spectroscopy and TEM results indicated that both size and optical properties of the Ag nanoparticles in the PEM can be controlled by manipulating ion content in the PEM and the number of the ion-exchange/reduction cycle, whereas that of Ag-Au bimetallic nanoparticles were dependent on size of the Ag templates and the replacement reaction kinetics. The hollow Ag-Au bimetallic nanoparticles exhibited a significant red shift in the surface plasmon resonance to the near-infrared region. The strategy enables facile preparation of hollow bimetallic nanoparticles in situ in polymer matrixes.
通过两步离子交换/还原过程（种子生长阶段），在聚电解质多层膜（PEMs）中成功合成了尺寸约为 20nm 且具有相当均一尺寸分布的 Ag 纳米颗粒，将其作为牺牲模板，通过电置换反应制备了 Ag-Au 双金属中空纳米颗粒。通过紫外-可见光谱监测反应过程。通过透射电子显微镜（TEM）和能量色散 X 射线能谱对纳米颗粒的形貌和结构进行了表征，证实了中空 Ag-Au 双金属纳米颗粒的形成。紫外-可见吸收光谱和 TEM 结果表明，通过控制 PEM 中的离子含量和离子交换/还原循环的次数，可以控制 PEM 中 Ag 纳米颗粒的尺寸和光学性质，而 Ag-Au 双金属纳米颗粒的尺寸则取决于 Ag 模板的尺寸和置换反应动力学。中空 Ag-Au 双金属纳米颗粒的表面等离子体共振在近红外区域发生了显著的红移。该策略可在聚合物基质中方便地原位制备中空双金属纳米颗粒。
