Nano-confined electrochemical reaction studied by electrochemical surface forces apparatus
Nano-confined electrochemical reaction studied by electrochemical surface forces apparatus
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电化学表面力装置研究纳米限域电化学反应
DOI：
10.1039/d1fd00060h
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发表时间：
2022
影响因子：
3.4
通讯作者：
Kurihara Kazue
中科院分区：
文献类型：
--
作者：
Kasuya Motohiro;Kubota Daiki;Fujii Sho;Kurihara Kazue
纳米空间中的电化学反应由于液体分子的结构和电双层上特殊的离子行为而不同于在整体溶液中的电化学反应，对于涉及传感器和能量器件的应用具有重要的意义。我们研制的电化学表面力装置(EC-SFA)使我们能够以纳米分辨率研究不同间距(D)的电极之间的纳米限制溶液中的电化学反应。我们使用我们的EC-SFA记录了由于氧化还原对在纳米限制的铂电极之间的电解液中的电化学反应而产生的电流-距离分布。我们观察到由于氧化还原循环而产生的长程反馈电流和在短距离内电流的突然增加，后者是第一次。这种突然的电流增加比传统的反馈电流大两个数量级，并且在电极接近时在D<；5 nm处观察到，在分离时在D<；200 nm处观察到。我们同时测量了溶液中的双电层力和电极间的电流，以研究这种短距离电流突然增加的机制。结果揭示了在纳米限制下氧化还原物种如何影响两个电极之间的电流的分子洞察力。这项研究表明，EC-SFA是获得有关纳米电极的纳米受限电化学反应的基础知识的有力工具，可以应用于传感器和能源设备。
Electrochemical reactions in a nano-space are different from those in bulk solutions due to structuring of the liquid molecules and peculiar ion behavior at the electric double layer and are important for applications involving sensors and energy devices. The electrochemical surface forces apparatus (EC-SFA) we developed enabled us to study the electrochemical reactions in a solution nano-confined between the electrodes with varying distance (D) at nm resolution. We recorded measurements of the current–distance profiles due to the electrochemical reaction of the redox couples in the electrolyte nano-confined between Pt electrodes using our EC-SFA. We observed a long-range feedback current due to redox cycling and the sudden current increase at a short distance, the latter for the first time. This sudden current increase was two orders greater than the conventional feedback current and was observed at D < 5 nm when the electrodes were approaching and D < 200 nm on separation. We simultaneously measured the electric double layer force and the current between the electrodes in the solution to study the mechanisms of this sudden current increase in the short distance range. The results revealed a molecular insight as to how the redox species affect the current between two electrodes under nano-confinement. This study demonstrated that EC-SFA is a powerful tool for obtaining fundamental knowledge about the nano-confined electrochemical reactions for nanoelectrodes which can be applied to sensors and energy devices.