Plasmonic Evolution and Arrested Development for Silver Nanoscale Colloids: A Classroom Demonstration
Plasmonic Evolution and Arrested Development for Silver Nanoscale Colloids: A Classroom Demonstration
复制标题
银纳米级胶体的等离子体演化和发展停滞：课堂演示
DOI：
10.1021/acs.jchemed.9b00638
复制
发表时间：
2019
影响因子：
3
通讯作者：
G. Baker
中科院分区：
文献类型：
--
作者：
Jason A. Thon;Nathaniel E. Larm;Yahor Vazmitsel;G. Baker
一个生动的演示可视化的胶体行为的银纳米晶体的描述。水-乙醇银离子溶液在初始化学还原（使用硼氢化钠，NaBH 4）时变为黄色，随后由于纳米晶体的可预测的生长和演变，在约3分钟的过程中颜色演变为橙子、红色、紫色和最后蓝色。这个本科水平的课堂演示对于说明钝化配体的保护作用是有用的，例如聚乙烯吡咯烷酮（PVP），通过显示PVP在所需阶段停止银胶体的生长和聚结的能力，在特定色调下阻止颜色过渡。该演示还可以扩展以突出这种钝化对胶体行为的分叉影响（例如，改进的长期胶体稳定性，伴随恶化的纳米催化性能）。
A vivid demonstration visualizing the colloidal behavior of silver nanocrystals is described. An aqueous–ethanol silver ion solution becomes yellow upon initial chemical reduction (using sodium borohydride, NaBH4), which is followed by chromatic evolution to orange, red, violet, and finally blue over the course of approximately 3 min because of the predictable growth and evolution of the nanocrystals. This undergraduate-level classroom demonstration is useful for illustrating the protective effect of a passivating ligand, such as polyvinylpyrrolidone (PVP), by showing the ability of PVP to halt the growth and coalescence of silver colloids at a desired stage, arresting the color transition at a particular hue. This demonstration can also be extended to highlight the bifurcated impact of such passivation on colloid behavior (e.g., improved long-term colloid stability coupled with worsened nanocatalytic performance).