The scanning electrochemical microscope is used to form and characterize patterns of oxides on glassy carbon surfaces. Chemically specific imaging of oxides present on these surfaces was demonstrated by taking advantage of differential heterogeneous electrontransfer rates for the Fe(II/III) reaction occurring at unoxidized and oxidized glassy carbon electrodes. Localized generation of surface oxides was demonstrated using both the microreagent and direct modification modes of SECM. The micro-reagent mode was used to perform a chemical oxidation of the surface by generating the strong oxidant Ag(II) at the UME tip while positioned close to the carbon surface, however, this technique was found to have poor reproducibility. Direct mode oxidation was found to be a much more versatile route toward the generation of complex patterns of oxides on carbon surfaces. The reproducibility of the direct mode technique was found to depend heavily on solution resistance. “Charge dose” studies, followed by reaction-rate imaging, qualitatively show that the electron-transfer rate for the Fe(II/III) system scales with the amount of charge “injected” in each oxidation experiment, indicating a correlation between surface oxide density and electron-transfer rate.
The Electrochemical Society
College of Arts and Sciences
Department of Chemistry
Glassy Carbon, Carbon Oxides, Scanning Electrochemical Microscopy, Electrochemistry, Electrodes, Electron Transfer
Wipf, David O. and Tenent, Robert C., "Patterning and Imaging of Oxides on Glassy Carbon Electrode Surfaces by Scanning Electrochemical Microscopy" (2003). College of Arts and Sciences Publications and Scholarship. 25.