HOPG (highly oriented pyrolytic graphite) and GC (glassy carbon) electrode surface feature modified with cobalt methyltetraphenylporphyrin (CoTPP) was investigated by scanning tunneling microscope combined with cyclic voltammograms. The effect of electrode surface morphologies on the electrocatalytic activity for oxygen reduction was discussed in detail. It was explained in nanometer scale that catalytic activity of the GC electrode was obviously higher than that of HOPG electrode for dioxygen reduction These results show that STM is a powerful tool for modified electrode surface characterizations.

Key words: CHEMICAL MODIFIED ELECTRODE, CYCLOVOLTAMGRAPH, GLASSY CARBON ELECTRODE, SURFACE MORPHOLOGY, SCANNING TUNNELING MICROSCOPE