Web Release Date: February 6,
Selective Insulation with Poly(tetrafluoroethylene) of Substrate Electrodes for Electrochemical Background Reduction in Scanning Electrochemical Microscopy
Center for Electrochemistry, Department of Chemistry and Biochemistry, University of Texas, Austin, Texas 78712
Received for review September 28, 2007. Accepted December 9, 2007.
Abstract:
We describe a wet process for the fabrication of poly(tetrafluoroethylene) (PTFE)-covered electrodes in which
arrays of holes (~200 
m) are formed. The PTFE coating
provides electrical insulation of most of the electrode
surface with selected regions exposed for electrochemical
experiments. The arrays of microholes can be controllably
patterned and filled with precursor solutions using a
piezoelectric dispenser. A micrometer spot of electrocatalyst is produced after reduction of the precursor. The
application is tested for scanning electrochemical microscopy (SECM) in the tip generation-substrate collection
(TG-SC) studies of electrocatalysts. The method is shown
to reduce the substrate background currents that are
included in the electrochemical signal read from the local
perturbation induced with the SECM tip to the substrate
in the TG-SC mode of SECM. This background current
reduction is consistent with the decrease in the exposed
area of the electrode. The general methodology for the
fabrication of the substrate electrodes and two proof-of-concept applications in the TG-SC SECM modality are
described.
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