Kostiuchenko Zinaida A, Cui Jin Z, Lemay Serge G
MESA+ Institute for Nanotechnology, University of Twente, PO Box 217, 7500 AE Enschede, The Netherlands.
J Phys Chem C Nanomater Interfaces. 2020 Jan 30;124(4):2656-2663. doi: 10.1021/acs.jpcc.9b08584. Epub 2020 Jan 9.
Fluid and charge transport in micro- and nanoscale fluidic systems are intrinsically coupled via electrokinetic phenomena. While electroosmotic flows and streaming potentials are well understood for externally imposed stimuli, charge injection at electrodes localized inside fluidic systems via electrochemical processes remains to a large degree unexplored. Here, we employ ultramicroelectrodes and nanogap electrodes to study the subtle interplay between ohmic drops, streaming currents, and faradaic processes in miniaturized channels at low concentrations of supporting electrolyte. We show that electroosmosis can, under favorable circumstances, counteract the effect of ohmic losses and shift the apparent formal potential of redox reactions. This interplay can be described by simple circuit models, such that the results described here can be adapted to other micro- and nanofluidic electrochemical systems.
在微纳尺度的流体系统中，流体和电荷传输通过电动现象内在地耦合在一起。虽然对于外部施加的刺激，电渗流和流动电位已得到充分理解，但通过电化学过程在流体系统内部局部电极处进行的电荷注入在很大程度上仍未得到探索。在这里，我们使用超微电极和纳米间隙电极来研究在低浓度支持电解质的小型化通道中，欧姆降、流动电流和法拉第过程之间的微妙相互作用。我们表明，在有利的情况下，电渗作用可以抵消欧姆损耗的影响，并改变氧化还原反应的表观形式电位。这种相互作用可以用简单的电路模型来描述，因此这里描述的结果可以应用于其他微纳流体电化学系统。
