Ershov Boris, Ershov Vadim
Frumkin Institute of Physical Chemistry and Electrochemistry, Russian Academy of Science, Leninsky Pr. 31-4, 119071 Moscow, Russia.
Nanomaterials (Basel). 2023 Jun 22;13(13):1907. doi: 10.3390/nano13131907.
For the first time, an electrochemical mechanism of oxidative dissolution of silver nanoparticles in aqueous solutions is suggested and substantiated. The dissolution is caused by the occurrence of two interrelated electrochemical processes: (1) silver oxidation on a microanode and (2) oxygen reduction on a microcathode. According to the suggested model, the standard electrode potential of a nanoparticle decreases with a decrease in its size, which leads to an increase in the electromotive force of the oxidative dissolution of silver. A proportional dependence of the solubility of nanoparticles on their standard potential is revealed. An empirical equation is derived that relates the solubility of AgNPs to their electrode potential and size. In the course of oxidation, silver nanoparticles undergo aggregation with a gradual increase in the potential to the value characteristic of the bulk metal. This leads to the deceleration and practical cessation of the dissolution.
首次提出并证实了银纳米颗粒在水溶液中氧化溶解的电化学机制。溶解是由两个相互关联的电化学过程引起的：（1）在微阳极上银的氧化和（2）在微阴极上氧的还原。根据所提出的模型，纳米颗粒的标准电极电位随着其尺寸的减小而降低，这导致银氧化溶解的电动势增加。揭示了纳米颗粒的溶解度与其标准电位之间的比例关系。推导了一个经验方程，该方程将AgNP的溶解度与其电极电位和尺寸联系起来。在氧化过程中，银纳米颗粒会发生聚集，电位逐渐升高至块状金属的特征值。这导致溶解速度减慢并实际停止。
