Improvement of Fe/MgO catalysts by calcination for the growth of single- and double-walled carbon nanotubes

Impregnation is used for the calcination of a Fe/MgO catalyst to result in a solid solution with the growth of single- and double-walled carbon nanotubes. The formation of iron layers on the catalyst surface is caused due to the hydrogen reduction resulting in a high yield of impurity-free nanotubes.