GASIFICATION OF GRAPHITE STUDIED BY SCANNING TUNNELING MICROSCOPY

We have used an STM to examine the gasification processes of graphite. The formation of monolayer voids on graphite surface during the noncatalytic oxidation reaction is confirmed, and a linear relationship between the radius of voids and time is found. Fast multilayer edge recession, which is independent of the depth of the edge, has also been observed. By measuring the radius at different temperatures, the activation energies for the oxidation of atoms at the monolayer edge and on the wall of multiple-layer steps have been determined to be 127 KJ/mol and 116 KJ/mol, respectively. Metal particles deposited on graphite produce multilayer channels because particles move as they catalyze channel formation in both H2 and O2.