Effect of support particle morphology of Ni catalysts on growth of carbon nanotubes by methane decomposition

The effect of the morphology of the support particles on nickel-catalyzed decomposition of methane into carbon nanotubes and hydrogen was explored using a thermogravimetric apparatus. Er 3 Ga 5 O 12 synthesized by the glycothermal method was used as the support of the Ni catalyst. As calcination temperature increased, morphology and pore-size distribution of Er 3 Ga 5 O 12 changed. High carbon nanotube yield was attained over Ni catalyst supported on Er 3 Ga 5 O 12 particles with spherical shape and smooth surfaces. Various aluminas were also examined for the support of the Ni catalysts. Quite high carbon yield was observed over Ni catalyst supported on spherical Al 2 O 3 particles (Nanophase Technologies Corp.). Spherical support particles with smooth surfaces touch at a point, so can change positions easily. Therefore, the most important factor governing the carbon yield is the morphology of the catalyst support.