Studying physical chemistry of glassy carbon surfaces with scanning tunneling microscopy and scanning tunneling spectroscopy

Investigations that began several years ago at the Karpov Institute of Physical Chemistry showed that fairly concentrated ozone can be synthesized on cooled anodes made of glassy carbon (GC). It was suggested that the high catalytic activity and stability of GC electrodes is determined by the change in their nanostructure during the surface modification under the electrolysis conditions, namely, the appearance of functionally active surface components involving nanoscale groups of a chemisorption nature. Scanning tunneling spectroscopy showed that any modification of glassy carbon produced by the changes in potential or some other kinds of treatment promotes changes in the electrophysical properties of the surface atoms. The donor-acceptor ratio of the properties of the GC surface atoms changes, as well as the effective electron-transfer resistance and the general tunneling activity of local surface sites. The modification of the GC surface by the electrochemical treatment in ammonium difluoride solutions results in a decrease in the effective electrontunneling resistance and an increase in the general tunneling activity by a coefficient of 2-2.5.