Preparation of Fe-filled carbon nanotubes by catalytic decomposition of cyclohexane

Carbon nanotubes were formed in situ during the reduction of Fe2O3 to Fe by a gas mixture of N2 (200 sccm), H2 (50 sccm), and cyclohexane (carried by H2) at 750 °C. Transmission electron microscopy (TEM) investigation showed that most of the formed nanotubes were filled with metal nanoparticles or nanorods. Some nanotubes were even inserted with long continuous nanowires more than several hundred nanometer in length. High-resolution TEM (HRTEM) and electronic energy loss spectrum (EELS) of the filled nanotubes confirmed the presence of Fe inside the nanotubes. Based on the experimental results, a possible growth mechanism of the Fe-filled nantotubes was proposed.