The Influence of Fe–Co/MgO Catalyst Composition on the Growth Properties of Carbon Nanotubes

Abstract

In this work, the effects on nanoparticle growth by varying the Fe:Co ratio present in a Fe–Co/MgO catalyst system were studied. Single-wall carbon nanotubes were synthesized using an inductive radio frequency chemical vapor deposition method; methane and acetylene were used separately as hydrocarbon sources. The catalyst systems and their resulting nanotubes were characterized by several techniques such as electronic microscopy, Raman spectroscopy, and X-ray diffraction. The Fe:Co ratio was found to influence morphological and structural properties of the catalyst systems. Among all the catalysts Fe–Co/MgO (2.5:2.5:95 wt.%) was found to produce CNTs with the highest efficiency. These results correlated well with the catalyst surface area measurements. The bimetallic catalyst systems have the highest surface area, leading to a higher catalytic decomposition of the hydrocarbon. Additionally, it was found that the SWCNTs synthesized on the Fe–Co/MgO (2.5:2.5:95 wt.%) with methane have narrow size diameter distributions and the characteristics of the major tubes seem to be determined by the catalyst rather than the carbon source.