Carbon nanotubes of narrow size distribution can be mass produced in the catalytic decomposition of CH4 over pre-reduced LaNiO3, La4Ni3O10, La3Ni2O7 and La2NiO4. The structure and component of the fresh and reduced LaNiO3, La4Ni3O10, La3Ni2O7 and La2NiO4 were determined by X- ray diffraction (XRD). The carbon nanotubes obtained were characterized by means of transmission electron microscopy (TEM), X- ray photoelectron spectroscopy (XPS). Thermal oxidation of carbon nanotubes in air was performed by thermogravimetric experiment (TG). The results reveral that a lower La/Ni ratio of the catalysts sould lead to a wider diameter distribution and a higher degree of graphitic nature.

Key words: PREREDUCTION, CATALYST, DOUBLE OXIDE, LANTHANUM COMPOUNDS, NICKEL COMPOUNDS, DECOMPOSITION, METHANE, GRAPHITIZATION, NANOPHASE MATERIALS