The ability to study electron transfer reactions at the solid–liquid interface with nanometer resolution has the potential to critically improve our understanding of electrocatalytic processes. However, few techniques are capable of studying electrode surfaces in situ at the nanoscale. We study the redox reactions of Nile Blue (NB) covalently tethered to an Au(111) electrode using in situ tip-enhanced Raman spectroscopy (TERS) and show that TERS amplitude decreases reversibly as NB is reduced. The potential dependent TERS intensity allows us to associate an electrochemical wave with the loss of electronic resonance of NB and another with the peak of fluorescence of tethered NB, which we tentatively attribute to the disassembly of on-surface NB aggregates. The study of the electrochemical activity of immobile adsorbates at the solid–liquid interface with TERS is an essential step toward the realization of in situ spectroscopic mapping at the nanoscale.

中文翻译：

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电化学STM尖端增强拉曼光谱研究共价键联发色团在Au（111）上的电子转移反应

研究具有纳米级分辨率的固液界面电子转移反应的能力有可能极大地提高我们对电催化过程的理解。然而，很少有技术能够在纳米尺度上原位研究电极表面。我们研究使用原位共价拴在Au（111）电极上的尼罗蓝（NB）的氧化还原反应尖端增强拉曼光谱（TERS），结果表明，随着NB的降低，TERS幅度可逆地降低。电位相关的TERS强度使我们能够将电化学波与NB的电子共振损失联系起来，将另一个与束缚的NB的荧光峰联系起来，我们暂时将其归因于表面NB聚集体的分解。与TERS在固液界面上固定的吸附物的电化学活性的研究是实现纳米级原位光谱图绘制的必不可少的步骤。