Quantitative Electrochemical Measurements Using In Situ ec-S/TEM Devices
| Autor: | Franklin S. Walden, Gabriel M. Veith, Daniel Stephen Gardiner, Gilbert M. Brown, Raymond R. Unocic, John Damiano, Nancy J. Dudney, David P. Nackashi, Robert L. Sacci, Karren L. More |
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| Rok vydání: | 2014 |
| Předmět: | |
| Zdroj: | Microscopy and Microanalysis. 20:452-461 |
| ISSN: | 1435-8115 1431-9276 |
| DOI: | 10.1017/s1431927614000166 |
| Popis: | Insight into dynamic electrochemical processes can be obtained with in situ electrochemical-scanning/transmission electron microscopy (ec-S/TEM), a technique that utilizes microfluidic electrochemical cells to characterize electrochemical processes with S/TEM imaging, diffraction, or spectroscopy. The microfluidic electrochemical cell is composed of microfabricated devices with glassy carbon and platinum microband electrodes in a three-electrode cell configuration. To establish the validity of this method for quantitative in situ electrochemistry research, cyclic voltammetry (CV), choronoamperometry (CA), and electrochemical impedance spectroscopy (EIS) were performed using a standard one electron transfer redox couple [Fe(CN)6]3−/4−-based electrolyte. Established relationships of the electrode geometry and microfluidic conditions were fitted with CV and chronoamperometic measurements of analyte diffusion coefficients and were found to agree with well-accepted values that are on the order of 10−5 cm2/s. Influence of the electron beam on electrochemical measurements was found to be negligible during CV scans where the current profile varied only within a few nA with the electron beam on and off, which is well within the hysteresis between multiple CV scans. The combination of experimental results provides a validation that quantitative electrochemistry experiments can be performed with these small-scale microfluidic electrochemical cells provided that accurate geometrical electrode configurations, diffusion boundary layers, and microfluidic conditions are accounted for. |
| Databáze: | OpenAIRE |
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