P. Chen et al., STUDIES ON STRUCTURE AND PROPERTY OF CARBON-NANOTUBES FORMED CATALYTICALLY FROM DECOMPOSITION OF CH4 OR CO, Gaodeng xuexiao huaxue xuebao, 19(5), 1998, pp. 765-769
By means of TEM, HRTEM, XRD, XPS and TPO methods, structure and proper
ties of the carbon-nanofibers formed catalytically from decomposition
of CH4 or CO have been investigated. The TEM observation shows that th
ese materials are,even nanotubes with the outer diameters of 15 simila
r to 20 nm, Their XRD patterns are very close to that of graphite, but
the XRD features are somewhat broadened, indicating that the degree o
f long-range order of these nanostructures is relatively low in compar
ison with that of graphite. HRTEM observation reveals that the wall of
these nanotubes is constructed by many layers of carbon with graphite
-like platelets in an extremely ordered arrangement, with the orientat
ion of the conical graphite-like platelets inclined to the central axi
s of the tube for the material produced from CH4 and the cylindrical g
raphite-like platelets parallel to the tube-axis for that from CO, res
pectively. XPS measurements show that C-1s electron binding energy in
these carbon-nanotubes is about 0.5 eV lower than that of graphite. Th
e results of the O-2-TPO testing demonstrate that content of amorphous
carbon in these materials is very low, and then; the nanostructures a
re entirely graphitic in nature; the TPO results also show that the te
mperature for gasification of the material-produced from CH4 is about
100 K higher than that from CO, indicating that the former has a bette
r oxygen-resistibility than the latter.