Scanning Electrochemical Cell Microscopy (SECCM) in Aprotic Solvents: Practical Considerations and Applications
Scanning Electrochemical Cell Microscopy (SECCM) in Aprotic Solvents: Practical Considerations and Applications
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DOI：
10.1021/acs.analchem.0c01540
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发表时间：
2020-09-01
影响因子：
7.4
通讯作者：
Unwin, Patrick R.
中科院分区：
文献类型：
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作者：
Bentley, Cameron L.;Kang, Minkyung;Unwin, Patrick R.
现代电化学中的许多应用，尤其是电合成和能量存储/转换，利用了非水（例如，非质子）电解质介质的“可调节”物理化学性质（例如，质子可用性和/或电化学稳定性）。这项工作制定了有关在非质子溶剂电解质介质中使用扫描电化学电池显微镜（SECCM）的一般指南，以解决当代结构电化学活性问题。使用简单的外球 Fc(0/+) 过程（Fc = 二茂铁）作为模型系统，高沸点（低蒸气压）溶剂会产生高度稳健且可重复的电化学，而挥发性（低沸点）溶剂需要与合适的低熔点支持电解质（例如离子液体）或高沸点溶剂混合，以避免扫描（分钟到小时）时间尺度上与盐沉淀/结晶相关的并发症。当用于执行微加工（特别是导电聚合物聚吡咯的电合成）时，优化的 SECCM 设置可在与所使用的移液管探针相称的规模上产生高度可重复的合成（电沉积）材料阵列。应用 SECCM 绘制电催化活性图，特别是碘化物在多晶铂上的电氧化，揭示了表面活性的独特（即结构依赖性）模式，其中特定晶体取向的晶粒、晶界和高局部表面取向错误的区域被确定为潜在的电催化“热点”。本文的工作进一步巩固了 SECCM 作为（电子）材料科学中结构-功能-活性研究的首要技术，并将通过使用非质子溶剂在电合成、微加工、电化学能量存储/转换等领域进行合理分析/设计，开辟令人兴奋的新可能性。
Many applications in modern electrochemistry, notably electrosynthesis and energy storage/conversion take advantage of the "tunable" physicochemical properties (e.g., proton availability and/or electrochemical stability) of nonaqueous (e.g., aprotic) electrolyte media. This work develops general guidelines pertaining to the use of scanning electrochemical cell microscopy (SECCM) in aprotic solvent electrolyte media to address contemporary structure-electrochemical activity problems. Using the simple outer-sphere Fc(0/+) process (Fc = ferrocene) as a model system, high boiling point (low vapor pressure) solvents give rise to highly robust and reproducible electrochemistry, whereas volatile (low boiling point) solvents need to be mixed with suitable low melting point supporting electrolytes (e.g., ionic liquids) or high boiling point solvents to avoid complications associated with salt precipitation/crystallization on the scanning (minutes to hours) time scale. When applied to perform microfabrication-specifically the electrosynthesis of the conductive polymer, polypyrrole-the optimized SECCM set up produces highly reproducible arrays of synthesized (electrodeposited) material on a commensurate scale to the employed pipet probe. Applying SECCM to map electrocatalytic activity-specifically the electrooxidation of iodide at polycrystalline platinum-reveals unique (i.e., structure-dependent) patterns of surface activity, with grains of specific crystallographic orientation, grain boundaries and areas of high local surface misorientation identified as potential electrocatalytic "hot spots". The work herein further cements SECCM as a premier technique for structure-function-activity studies in (electro)materials science and will open up exciting new possibilities through the use of aprotic solvents for rational analysis/design in electrosynthesis, microfabrication, electrochemical energy storage/conversion, and beyond.