In this study, carbon fibers were formed from acetylene decomposition on hydrogen-reduced Pd and Ni catalysts at 450–700 °C. X-ray diffraction (XRD) was used to examine the crystal characteristics of catalysts and carbon fibers. The carbon fibers were also examined both by scanning electron microscopy (SEM) and Raman spectroscopy to define their appearance and structure. Little amount of carbon fibers were found on the Pd catalyst surface at 450 °C; while a significant amount of carbon filaments were observed at 650 °C. In comparison, more carbon filaments were observed on the Ni catalysts at 450 °C. According to the XRD spectrum, there was carbon and graphite present on the Ni surface. Raman spectroscopy revealed two peaks at 1290 cm−1 (D band, disorder mode, amorphous carbon) and 1590 cm−1 (G band, graphite sp2 structure). SEM results indicated the Ni could catalyze the C2H2 decomposition to form carbon filaments at a lower temperature than Pd. Furthermore, C2H2 was decomposed on Ni catalyst at 450 °C; the formation of carbon nanotubes by decomposing C2H2 on Ni at 450 °C was a relatively low temperature.
Journal of Alloys and Compounds, Volumes 434-435, Pages 846-849