Micrometer-Precise Determination of the Thin Electrolyte Layer of a Spectroelectrochemical Cell by Microelectrode Approach Curves.
A spectroelectrochemical cell is presented that allows investigations of electrochemical reactions by means of attenuated total reflection infrared (ATR-IR) spectroscopy. The electrode holder for the working (WE), counter and reference electrode as mounted in the IR spectrometer cause the formation of a thin electrolyte layer between the internal reflection element (IRE) and the surface of the WE. The thickness of this thin electrolyte layer (dTL) was estimated by performing a scanning electrochemical microscopy-(SECM) like approach of a Pt microelectrode (ME), which was leveled with the WE toward the IRE surface. The precise lowering of the ME/WE plane toward the IRE was enabled by a micrometer screw. The approach curve was recorded in negative feedback mode of SECM and revealed the contact point of the ME and WE on the IRE, which was used as reference point to perform the electro-oxidation of ethanol over a drop-casted Pd/NCNT catalyst on the WE at different thin-layer thicknesses by cyclic voltammetry. The reaction products were detected in the liquid electrolyte by IR spectroscopy, and the effect of variations in dTLon the current densities and IR spectra were analyzed and discussed. The obtained data identify dTLas an important variable in thin-layer experiments with electrochemical reactions and FTIR readout.
Laboratory of Industrial Chemistry, ‡Analytical Chemistry - Center for Electrochemical Sciences (CES), §Mechanical Workshop of the Faculty of Chemistry and Biochemistry, Ruhr-Universität Bochum , Universitätsstr. 150, D-44780 Bochum, Germany.
Dennis
D
Hiltrop
Laboratory of Industrial Chemistry, ‡Analytical Chemistry - Center for Electrochemical Sciences (CES), §Mechanical Workshop of the Faculty of Chemistry and Biochemistry, Ruhr-Universität Bochum , Universitätsstr. 150, D-44780 Bochum, Germany.
Justus
0000-0002-8555-5157
J
Masa
Laboratory of Industrial Chemistry, ‡Analytical Chemistry - Center for Electrochemical Sciences (CES), §Mechanical Workshop of the Faculty of Chemistry and Biochemistry, Ruhr-Universität Bochum , Universitätsstr. 150, D-44780 Bochum, Germany.
Alexander J R
AJR
Botz
Laboratory of Industrial Chemistry, ‡Analytical Chemistry - Center for Electrochemical Sciences (CES), §Mechanical Workshop of the Faculty of Chemistry and Biochemistry, Ruhr-Universität Bochum , Universitätsstr. 150, D-44780 Bochum, Germany.
Armin
A
Lindner
Laboratory of Industrial Chemistry, ‡Analytical Chemistry - Center for Electrochemical Sciences (CES), §Mechanical Workshop of the Faculty of Chemistry and Biochemistry, Ruhr-Universität Bochum , Universitätsstr. 150, D-44780 Bochum, Germany.
Wolfgang
0000-0003-2916-5223
W
Schuhmann
Laboratory of Industrial Chemistry, ‡Analytical Chemistry - Center for Electrochemical Sciences (CES), §Mechanical Workshop of the Faculty of Chemistry and Biochemistry, Ruhr-Universität Bochum , Universitätsstr. 150, D-44780 Bochum, Germany.
Martin
0000-0001-5343-6922
M
Muhler