Effect of the catalyst structure on the formation of carbon nanotubes over Ni/MgO catalyst

Abstract

Ni/MgO solid solution catalyst was prepared by decomposition of nickel and magnesium nitrate using dielectric barrier discharge (DBD) plasma operated at atmospheric pressure and less than 175°C. Well-defined lattice fringes of the Ni (111) plane are clearly observed in the plasma prepared Ni/MgO catalyst. The plasma prepared catalyst possesses fewer defects, compared to the catalyst prepared by thermal decomposition at elevated temperature. It results in a better balance between the carbon formation and the carbon nanotube (CNT) growth. The crystallinity of the Ni particle from thermal decomposition is more complex. It is difficult to distinguish the Ni planes with the thermal decomposed catalyst. CNTs from CO decomposition over the plasma made catalyst show a narrow diameter distribution with a high aspect ratio. The DBD plasma decomposition is a facile, simple and effective way for the preparation of Ni catalysts to fabricate high quality CNTs.