Synthesis of single-walled carbon nanotube–Co–MgO composite powders and extraction of the nanotubes

Abstract

A carbon nanotube–Co–MgO composite powder is prepared by reducing a Mg_0.9Co_0.1O solid solution in H₂–CH₄ atmosphere. The oxide matrix and part of the Co catalyst are dissolved by acid treatment without damage to the nanotubes. More than 80% of the carbon nanotubes have either one or two walls. The diameters of the nanotubes are in the range 0.5–5 nm. The utilized method may be a real improvement in the low-cost, large-scale synthesis of single- and double-walled carbon nanotubes.