Department of Chemistry, McGill University, MontrealQC H3A 0B8, Canada.
Automotive and Surface Transportation, National Research Council Canada, SaguenayQC G7H 8C3, Canada.
Anal Chem. 2022 Nov 8;94(44):15315-15323. doi: 10.1021/acs.analchem.2c02681. Epub 2022 Oct 25.
Scanning electrochemical microscopy (SECM) is a powerful technique for imaging the electrochemical reactivity of a surface. Unfortunately, SECM images are mainly used qualitatively. Kinetics of reactions at the surface are almost exclusively obtained from the microelectrode current as it approaches the surface, called an approach curve. The approach curve method is excellent when the reaction at the surface has the same kinetics everywhere, but was not designed to fit the kinetics of finite-sized reactive features. We propose a method for extracting kinetics, feature area, and microelectrode tip-to-substrate distance from SECM images by fitting with simulated images of reactive discs using the Levenberg-Marquardt algorithm. The area of experimental reactive features can be fit to within 10% if the underlying feature is roughly disc-shaped. When the reaction at simulated reactive features is activation-limited, the rate constant can be fit to within 15% of the true value. This work heralds the beginning of quantifying kinetics from SECM images.
扫描电化学显微镜（SECM）是一种用于成像表面电化学反应性的强大技术。不幸的是，SECM 图像主要用于定性分析。表面反应的动力学几乎完全是从微电极接近表面时的电流获得的，称为接近曲线。当表面反应在各处具有相同的动力学时，接近曲线方法非常出色，但它不是为拟合有限大小反应特征的动力学而设计的。我们提出了一种通过使用 Levenberg-Marquardt 算法拟合使用反应盘的模拟图像，从 SECM 图像中提取动力学、特征区域和微电极尖端到基底距离的方法。如果基础特征大致为圆盘形，则可以将实验反应特征的面积拟合在 10%以内。当模拟反应特征的反应受到活化限制时，速率常数可以拟合在真实值的 15%以内。这项工作标志着从 SECM 图像中定量提取动力学的开始。
