Quantitative Electrochemical Measurements using in situ ec-S/TEM Devices

Journal Article · Wed Jan 01 00:00:00 EST 2014 · Microscopy and Microanalysis

DOI:https://doi.org/10.1017/S1431927614000166· OSTI ID:1123576

Unocic, Raymond R ^[1]; Sacci, Robert L ^[1]; Brown, Gilbert M ^[1]; Veith, Gabriel M ^[1]; Dudney, Nancy J ^[1]; More, Karren Leslie ^[1]; Gardiner, Daniel ^[2]; Walden, II, Franklin S ^[2]; Damiano, John ^[2]; Nackashi, David P. ^[2]

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1. ORNL
2. Protochips Inc., Raleigh, NC

Insight into dynamic electrochemical processes can be obtained with in situ ec-S/TEM, which 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, choronoamperometry and electrochemical impedance spectroscopy were performed using a standard one electron transfer redox couple using a [Fe(CN)6]3-/4- based electrolyte. Established relationships of the electrode geometry and microfluidic conditions were fitted with cyclic voltammetry and chronoamperometic measurements of analyte diffusion coefficients and was found to agree with well-accepted values that are on the order of 10-5 cm2 s-1. 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.

• Research Organization: Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Center for Nanophase Materials Sciences (CNMS)
• Sponsoring Organization: USDOE Office of Science (SC)
• DOE Contract Number: DE-AC05-00OR22725
• OSTI ID: 1123576
• Journal Information: Microscopy and Microanalysis, Journal Name: Microscopy and Microanalysis; ISSN 1431--9276
• Country of Publication: United States
• Language: English