Ag@C core/shell structured nanoparticles: Controlled synthesis, characterization, and assembly
Ag@C core/shell structured nanoparticles: Controlled synthesis, characterization, and assembly
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作者：
Sun, XM;Li, YD
采用绿色湿化学方法--水热条件下葡萄糖催化脱水，将尺寸可调的银纳米粒子包裹在碳质壳层中。在这种一锅法合成中，葡萄糖被用作还原剂与Ag+或Ag（NH3）（2）（+）反应，并且它也充当碳壳的来源。系统地研究了水热温度、时间和反应物浓度对纳米结构形成的影响。发现竞争性分子聚（乙烯基吡咯烷酮）的存在能够减轻碳化过程，将它们自身并入碳质壳中，并且使碳质壳无色。所有这些方法提供了不同的手段来定制Ag@C纳米结构。通过在潮湿环境中逐渐蒸发溶剂，单分散纳米粒子可以自组装成阵列。使用透射电子显微镜、扫描电子显微镜、紫外可见消光光谱和表面增强拉曼光谱来表征核/壳纳米结构。这些Ag@C核/壳纳米粒子具有亲水性、表面负载有机基团和独特的光学性质，在光学纳米器件和生物化学领域具有广阔的应用前景。
Silver nanoparticles with tunable sizes were encapsulated in a carbonaceous shell through a green wet chemical route-the catalyzed dehydration of glucose under hydrothermal condition. In this one-pot synthesis, glucose was used as the reducing agent to react with Ag+ or Ag(NH3)(2)(+), and it also served as the source of carbonaceous shells. The effects of hydrothermal temperature, time, and the concentrations of reagents on formation of the final nanostructures were systematically studied. The presence of competitive molecules poly(vinyl pyrrolidone) was found to be able to relieve the carbonization process, to incorporate themselves into carbonaceous shell, and to make the carbonaceous shell colorless. All these approaches provided diverse means to tailor the Ag@C nanostructures. By evaporation of the solvents gradually in a moist atmosphere, the monodispersed nanoparticles could self-assemble into arrays. Transmission electron microscopy, scanning electron microscopy, and UV-vis extinction spectra and surface-enhanced Raman spectra were used to characterize the core/shell nanostructures. These Ag@C core/shell nanoparticles have hydrophilic, organic-group-loaded surfaces and characteristic optical properties, which indicated their promising applications in optical nanodevices and biochemistry.