Catalytic decomposition of acetylene over CoFe2O4/BaFe12O19 core shell nanoparticles for the production of carbon nanotubes

In this study, carbon nanotubes were formed by acetylene decomposition on hydrogen-reduced CoFe2O4/BaFe12O19 core shell catalysts at 500–800 °C. X-ray diffraction (XRD) was used to examine the crystal characteristics of catalysts. The carbon nanotubes were also examined both by transmission electron microscopy (TEM) to define their appearance and structure. Little amount of carbon nanotubes were found on the catalyst surface at 500 and 800 °C; while a significant amount of carbon nanotubes were observed at 700 °C. According to the XRD spectrum, there was bimetallic phase present. FT-IR spectroscopy revealed four peaks at 283.48, 269.02, 256.48 and 1577.49 cm−1 that indicating the presence of multi-walled carbon nanotubes. TEM results indicated that the reduction of CoFe2O4/BaFe12O19 core shell catalyzes the C2H2 decomposition to form carbon filaments at higher temperatures than the lower temperatures. The rates of decomposition of the acetylene, the kinetic curves of the decomposition were calculated; from activation energy calculation it was found that the mechanisms were controlled by physisorption.