Department of Chemistry, University of Washington , Seattle, Washington 98195, United States.
J Am Chem Soc. 2017 Sep 6;139(35):12274-12282. doi: 10.1021/jacs.7b06431. Epub 2017 Aug 24.
The electrochemical interface is an ultrathin interfacial region between the electrode surface and the electrolyte solution and is often characterized by numerous dynamic processes, such as solvation and desolvation, heterogeneous electron transfer, molecular adsorption and desorption, diffusion, and surface rearrangement. Many of these processes are driven and modulated by the presence of a large interfacial potential gradient. The study and better understanding of the electrochemical interface is important for designing better electrochemical systems where their applications may include batteries, fuel cells, electrocatalytic water splitting, corrosion protection, and electroplating. This, however, has proved to be a challenging analytical task due to the ultracompact and dynamic evolving nature of the electrochemical interface. Here, we describe the use of an electrochemical nanocell to image the dynamic collision and oxidation process of single silver nanoparticles at the surface of a platinum nanoelectrode. A nanocell is prepared by depositing a platinum nanoparticle at the tip of a quartz nanopipette forming a bipolar nanoelectrode. The compact size of the nanocell confines the motion of the silver nanoparticle in a 1-D space. The highly dynamic process of nanoparticle collision and oxidation is imaged by single-particle fluorescence microscopy. Our results demonstrate that silver nanoparticle collision and oxidation is highly dynamic and likely controlled by a strong electrostatic effect at the electrode/solution interface. We believe that the use of a platinum nanocell and single molecule/nanoparticle fluorescence microscopy can be extended to other systems to yield highly dynamic information about the electrochemical interface.
电化学界面是电极表面和电解质溶液之间的超薄界面区域，通常具有许多动态过程，例如溶剂化和去溶剂化、异相电子转移、分子吸附和解吸、扩散和表面重排。这些过程中的许多过程是由存在大的界面电势梯度驱动和调节的。研究和更好地理解电化学界面对于设计更好的电化学系统很重要，其应用可能包括电池、燃料电池、电催化水分解、腐蚀保护和电镀。然而，由于电化学界面的超紧凑和动态演变性质，这已被证明是一项具有挑战性的分析任务。在这里，我们描述了使用电化学纳米腔来成像单个银纳米颗粒在铂纳米电极表面的动态碰撞和氧化过程。通过在石英纳米管的尖端沉积铂纳米颗粒来制备纳米腔，从而形成双极纳米电极。纳米腔的紧凑尺寸将银纳米颗粒的运动限制在一维空间内。通过单粒子荧光显微镜成像来观察纳米颗粒碰撞和氧化的高度动态过程。我们的结果表明，银纳米颗粒的碰撞和氧化是高度动态的，可能受到电极/溶液界面处强静电效应的控制。我们相信，使用铂纳米腔和单分子/纳米颗粒荧光显微镜可以扩展到其他系统，以获得关于电化学界面的高度动态信息。
