Blount Brandon, Juarez Gabriel, Wang Yufei, Ren Hang
Department of Chemistry, The University of Texas at Austin, 105 E 24th St, Austin, TX 78712, USA.
Faraday Discuss. 2022 Apr 5;233(0):149-162. doi: 10.1039/d1fd00046b.
Nanoscale electrochemical mapping techniques, , scanning electrochemical cell microscopy (SECCM), have been increasingly used to study the local electrochemistry in electrocatalysis. Its capability for local electrochemistry mapping helps to reveal the heterogeneity in the electrode kinetics and mechanisms, which are otherwise averaged out in ensemble measurements. Accurate determination of the electrode kinetics requires the careful assessment of the ohmic potential drop in the solution, , the drop. Herein, the drop in SECCM experiments is assessed. We showed that the drop in single-barrel SECCM can be estimated using the solution conductivity and pipette geometry, or the mass transfer limiting current without the assumption of pipette geometry. For dual-barrel SECCM, we developed a method of measuring the solution resistance directly, which can be used to compensate for the drop and the potential shift in the experiments. These methods offer a convenient way to estimate and compensate for the drop in SECCM, allowing the more accurate measurement of local electrode kinetics for the determination of local mechanisms in electrocatalysis.
纳米级电化学测绘技术，如扫描电化学池显微镜（SECCM），已越来越多地用于研究电催化中的局部电化学。其进行局部电化学测绘的能力有助于揭示电极动力学和机理中的不均匀性，而这些在总体测量中会被平均掉。准确测定电极动力学需要仔细评估溶液中的欧姆电位降，即 降。在此，对SECCM实验中的 降进行评估。我们表明，单管SECCM中的 降可以使用溶液电导率和移液管几何形状，或在不假设移液管几何形状的情况下使用传质极限电流来估计。对于双管SECCM，我们开发了一种直接测量溶液电阻的方法，该方法可用于补偿实验中的 降和电位偏移。这些方法为估计和补偿SECCM中的 降提供了一种便捷方式，从而能够更准确地测量局部电极动力学，以确定电催化中的局部机理。
