McKelvey Kim, Robinson Donald A, Vitti Nicholas J, Edwards Martin A, White Henry S
Department of Chemistry, University of Utah, Salt Lake City, UT 84112, USA.
Faraday Discuss. 2018 Oct 1;210(0):189-200. doi: 10.1039/c8fd00014j.
An adjustable width (between 600 nm and 20 μm) gap between two Au microelectrodes is used to probe the electrodissolution dynamics of single Ag nanoparticles. One Au microelectrode is used to drive the oxidation and subsequent dissolution of a single Ag nanoparticle, which displays a multi-peak oxidation behavior, while a second Au microelectrode is used to collect the Ag+ that is produced. Careful analysis of the high temporal resolution current-time traces reveals capacitive coupling between electrodes due to the sudden injection of Ag+ ions into the gap between the electrodes. The current-time traces allow measurement of the effect of citrate concentration on the electrodissolution dynamics of a single Ag nanoparticle, which reveals that the presence of 2 mM citrate significantly slows down the release of Ag+. Intriguingly, these experiments also reveal that only a portion (ca. 50%) of the oxidized Ag nanoparticle is released as free Ag+ regardless of citrate concentration.
两个金微电极之间的间隙宽度可调（在600纳米至20微米之间），用于探测单个银纳米颗粒的电溶解动力学。一个金微电极用于驱动单个银纳米颗粒的氧化及随后的溶解，该银纳米颗粒呈现多峰氧化行为，而另一个金微电极用于收集产生的Ag⁺。对高时间分辨率的电流 - 时间曲线进行仔细分析，发现由于Ag⁺离子突然注入电极之间的间隙，电极之间存在电容耦合。电流 - 时间曲线能够测量柠檬酸盐浓度对单个银纳米颗粒电溶解动力学的影响，结果表明2 mM柠檬酸盐的存在显著减缓了Ag⁺的释放。有趣的是，这些实验还表明，无论柠檬酸盐浓度如何，只有一部分（约50%）氧化的银纳米颗粒以游离Ag⁺的形式释放。
