Influence of the composition of Fe2O3/Al2O3 catalysts on the rate of production and quality of carbon nanotubes

Multi-wall carbon nanotubes (MWCNTs) were grown on a series of X% Fe2O3/Al2O3 catalysts by thermal cracking of C2H4 at 650 °C for 1 h. The catalysts with compositions ranging from 0 to 100 wt.% Fe2O3, were prepared by controlled explosive burning of their nitrate precursors. The generated MWCNTs were characterized with SEM and TEM, along with thermo gravimetric and Raman analysis. Results show that the final yield and quality of the MWCNTs are dependent on the iron oxide content of the catalyst, which controls the size of the hematite particles. The optimal loading of iron oxide was found to be 75 wt.%, which resulted in the formation of relatively small hematite particles. Catalysts were examined for structural characteristics with the BET and XRD methods, as well as by SEM and TEM analysis.