Collision, Adhesion, and Oxidation of Single Ag Nanoparticles on a Polysulfide-Modified Microelectrode
Collision, Adhesion, and Oxidation of Single Ag Nanoparticles on a Polysulfide-Modified Microelectrode
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DOI：
10.1021/jacs.1c07164
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发表时间：
2021-09-22
影响因子：
15
通讯作者：
Zhang, Bo
中科院分区：
文献类型：
--
作者：
Defnet, Peter A.;Zhang, Bo
我们报道了单个银纳米粒子（Ag NPs）在多硫化物修饰的金微电极上的碰撞、粘附和氧化行为。尽管其在体积分析中对于较小的Ag NPs取得了显著的成功，但是由于不可控的碰撞行为和不完全的NP氧化，NP-碰撞电化学方法未能分析大于50 nm的颗粒。在这里，我们描述了独特的能力，在控制银纳米粒子的碰撞行为，通过大幅提高其粘附在电极上的概率的一个多硫化物层。硫代硫酸钠电氧化在金上形成的亚硫酸盐层既作为碰撞纳米粒子的粘合界面，又作为预浓缩的反应介质，化学氧化Ag形成Ag 2S。作为刘易斯碱的大量硫代硫酸钠的存在进一步促进了颗粒的快速溶解，其将生成的Ag 2S的溶解度显著提高了10倍（13）。多硫化物和硫代硫酸钠的组合使用使我们能够观察到NP检测频率增加25倍，峰值振幅增加3倍，以及较大Ag NP的更完全氧化。通过认识到使用透射电子显微镜（TEM）的体积分析如何可能高估准球形NP，我们相信我们可以对高达100 nm的颗粒进行完全NP氧化。通过专注于更有效的NP-电极接触的电极/溶液界面，我们预计，从这项研究中学到的知识将大大有利于未来的NP碰撞系统的机制研究，在单实体电化学以及设计超灵敏的生化传感器。
We report the collision, adhesion, and oxidation behavior of single silver nanoparticles (Ag NPs) on a polysulfide-modified gold microelectrode. Despite its remarkable success in volume analysis for smaller Ag NPs, the method of NP-collision electrochemistry has failed to analyze particles greater than 50 nm due to uncontrollable collision behavior and incomplete NP oxidation. Herein, we describe the unique capability of an ultrathin polysulfide layer in controlling the collision behavior of Ag NPs by drastically improving their sticking probability on the electrode. The ultrathin sulfurous layer is formed on gold by sodium thiosulfate electro-oxidation and serves both as an adhesive interface for colliding NPs and as a preconcentrated reactive medium to chemically oxidize Ag to form Ag2S. Rapid particle dissolution is further promoted by the presence of bulk sodium thiosulfate serving as a Lewis base, which drastically improves the solubility of generated Ag2S by a factor of 10(13). The combined use of polysulfide and sodium thiosulfate allows us to observe a 25x increase in NP detection frequency, a 3x increase in peak amplitude, and more complete oxidation for larger Ag NPs. By recognizing how volumetric analysis using transmission electron microscopy (TEM) may overestimate quasi-spherical NPs, we believe we can have full NP oxidation for particles up to 100 nm. By focusing on the electrode/solution interface for more effective NP-electrode contact, we expect that the knowledge learned from this study will greatly benefit future NP collision systems for mechanistic studies in single-entity electrochemistry as well as designing ultrasensitive biochemical sensors.