Growth of carbon nanotubes and microfibers over stainless steel mesh by cracking of methane

The La2NiO4 film was synthesized on the 304 stainless steel (SS) mesh. The hydrogen reduction of La2NiO4 generated homogeneous nano-catalyst particles (probably Ni/La2O3) over which methane was cracked, producing carbon nanotubes/microfibers and hydrogen. The carbon nanotubes/microfibers were strongly bonded to the SS mesh. It was observed that the methane conversion always reached its maximum at the cracking temperature of 750 °C regardless of its concentration varying from 5% to 100%. The cracking of 5% methane diluted in nitrogen generated multiwalled carbon nanotubes while the cracking of 10–100% methane resulted in the formation of carbon solid microfibers together with globular carbon particles. Higher concentration of methane created thicker carbon fibers and a 30% concentration of methane resulted in the highest deposits of carbon on the mesh. After a compressed air blow and ultrasonic treatment, the carbon deposits were still strongly adhered to the mesh. As a result of the carbon tubes/fibers coverage, the specific surface area of the SS mesh was enhanced significantly from 0.03 m2/g to 21–45 m2/g. XRD, HRTEM and Raman studies confirmed that the carbon products were of graphitic structure. Such advanced mesh material would have great application potential in industrial catalysis and other areas.