Probing Graphene Interfacial Reactivity via Simultaneous and Colocalized Raman–Scanning Electrochemical Microscopy Imaging and Interrogation
Probing Graphene Interfacial Reactivity via Simultaneous and Colocalized Raman–Scanning Electrochemical Microscopy Imaging and Interrogation
复制标题
通过同步共定位拉曼扫描电化学显微镜成像和询问探测石墨烯界面反应性
DOI：
10.1021/acs.analchem.8b00730
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发表时间：
2018
影响因子：
7.4
通讯作者：
Rodríguez-López, Joaquín
中科院分区：
文献类型：
--
作者：
Schorr, Noah B.;Jiang, Annie G.;Rodríguez-López, Joaquín
解决界面电化学中的挑战需要多模态方法，将材料的局部结构和反应性与高空间和时间多功能性联系起来。在此，我们引入时空相关拉曼光谱和扫描电化学显微镜（SECM）来研究结构异质性、界面分解产物和层数对石墨烯电极电子转移性能的影响。通过将SECM探针和激光线共定位，我们成功地以低于10 μm的分辨率以5 s /像素的速率获得了一致的SECM和拉曼图像，并以高达20的信噪比获得了每像素的全光谱。微图案石墨烯电极的SECM成像显示其反应性高度依赖于G峰的强度，G峰是石墨烯层数的一个指标。我们使用[Fe(CN)6]3 - /4 -氧化还原对作为介质，进一步监测了向正电位偏移的影响。Raman-SECM使我们能够在同一地点实时解耦不同结构效应对氧化还原反应的影响，包括剥离、缺陷密度增加和表面膜形成。原位拉曼光谱和SECM的耦合提供了一种强大的表面敏感分析方法来阐明与能量、催化和传感相关的界面特性。
Addressing challenges in interfacial electrochemistry requires multimodal approaches that correlate the local structure and reactivity of materials with high spatial and temporal versatility. Here, we introduce spatiotemporally correlated Raman spectroscopy and scanning electrochemical microscopy (SECM) to study the impact that structural heterogeneities, interfacial decomposition products, and layer number have on the electron-transfer properties of graphene electrodes. By colocalizing the SECM probe and laser line, we successfully obtained congruent SECM and Raman images at a rate of 5 s per pixel with sub-10 μm resolution, obtaining full spectra per pixel at a signal-to-noise ratio as high as ∼20. SECM imaging of a micropatterned graphene electrode showed its reactivity to be highly dependent on the intensity of the G peak, an indicator of the number of graphene layers. We further monitored the impact of excursions to positive potentials using the [Fe(CN)6]3–/4–redox pair as mediator. Raman–SECM allowed us to decouple the contributions to the redox response of different structural effects including exfoliation, increase in defect density, and surface film formation, on thesame siteand in real time. The coupling of in situ Raman spectroscopy and SECM provides a powerful surface-sensitive analytical approach to elucidate interfacial properties relevant to energy, catalysis, and sensing.