Carbon nanotubes growth catalyzed by La2NiO4

Ni - based A(2)BO(4) - type mixed oxide, La2NiO4, was prepared by means of a citric acid complexing method. X-ray diffraction pattern identified it as a single phase with a tetragonal K2NiF4 structure in which Ni2+ and La3+ i ons were evenly distributed. It also indicated the nickel existed mainly as Ni-0 after reducing. Rare earth oxides, La2O3, could prevent transition me tal from agglomerating and promote dispersion of nanoscale Ni-0 particles, which was very advantageous for carbon nanotube growth. A large amount of c arbon nanotubes from catalytic decomposition of CH4 and disproportionation of CO were obtained using La2NiO4 oxides as catalyst precursor. The morphol ogy of the carbon nanotubes was examined by transmission electron microscop y (TEM) and scanning electron microscopy (SEM). High resolution transmissio n electron microscopy image and Raman spectrum of carbon nanotubes showed t hey were multi - walled nanotubes with a higher degree of graphitization.