The effects of hydrogen and temperature on the growth and microstructure of carbon nanotubes obtained by the Fe(CO)5 gas-phase-catalytic chemical vapor deposition

Carbon nanotubes (CNTs) were grown by a gas-phase-catalytic chemical vapor deposition technique with the iron pentacarbonyl-acetylene-hydrogen system at 600-750 °C for 15 min. The addition of hydrogen accelerated the organized CNT growth at 750 °C by activating the poisoned catalysts. With the incorporation of hydrogen, CNTs showed a bamboo-like structure. The diameters of nanotubes were 15-35 nm with a small dimension at higher growth temperature of 750 °C. Long CNTs with a tube length of 450 μm displayed the folded microstructure. The analysis of Raman spectra also gave the evidences of the existing defects in CNTs. Our kinetic formulation can be applied to explain the effects of hydrogen and growth temperature on the CNT growth.