Electrochemical liquid cell transmission electron microscopy (TEM) is a unique technique for probing nanocatalyst behavior during operation for a range of different electrocatalytic processes, including hydrogen evolution reaction (HER), oxygen evolution reaction (OER), oxygen reduction reaction (ORR), or electrochemical CO2 reduction (eCO2R). A major challenge to the technique's applicability to these systems has to do with the choice of substrate, which requires a wide inert potential range for quantitative electrochemistry, and is also responsible for minimizing background gas generation in the confined microscale environment. Here, we report on the feasibility of electrochemical experiments using the standard redox couple Fe(CN)63−/4− and microchips featuring carbon-coated electrodes. We electrochemically assess the in situ performance with respect to flow rate, liquid volume, and scan rate. Equally important with the choice of working substrate is the choice of the reference electrode. We demonstrate that the use of a modified electrode setup allows for potential measurements relatable to bulk studies. Furthermore, we use this setup to demonstrate the inert potential range for carbon-coated electrodes in aqueous electrolytes for HER, OER, ORR, and eCO2R. This work provides a basis for understanding electrochemical measurements in similar microscale systems and for studying gas-generating reactions with liquid electrochemical TEM.

中文翻译：

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在透射电子显微镜中用于原位氧化还原研究的碳电极的电化学行为

电化学液体电池透射电子显微镜 (TEM) 是一种独特的技术，用于探测纳米催化剂在一系列不同电催化过程的操作过程中的行为，包括析氢反应 (HER)、析氧反应 (OER)、氧还原反应 (ORR) 或电化学CO2减少（eCO2R)。该技术对这些系统的适用性的主要挑战与基板的选择有关，这需要广泛的惰性电位范围用于定量电化学，并且还负责在受限的微尺度环境中尽量减少背景气体的产生。在这里，我们报告了使用标准氧化还原对 Fe(CN) 进行电化学实验的可行性63−/4-和具有碳涂层电极的微芯片。我们通过电化学方法评估原位在流速、液体体积和扫描速率方面的性能。与工作基板的选择同样重要的是参比电极的选择。我们证明使用改进的电极设置可以进行与批量研究相关的潜在测量。此外，我们使用此设置来展示碳涂层电极在 HER、OER、ORR 和 eCO 的水性电解质中的惰性电位范围2R. 这项工作为理解类似微尺度系统中的电化学测量和研究液体电化学 TEM 的气体生成反应提供了基础。