Formation of catalyst nanoparticles for the growth of carbon nanotubes during annealing of amorphous Co-Zr-O films

Abstract

The formation of nanosized catalyst particles for the growth of carbon nanotubes can be carried out during the crystallization of amorphous films consisting of two metals, one of which has higher free energy of the oxide. During annealing in the presence of oxygen, this metal is oxidized with the reduction of the second metal, which leads to the formation of nanoparticles embedded in the oxide of the first metal. This the process has been experimentally and theoretically studied by the example of the formation of cobalt nanoparticles on the surface of amorphous Co-Zr-O films as a result of the decomposition of a supersaturated solid solution and mechanical stresses arising during the oxidation of zirconium. We have proposed a mechanism for the formation of catalyst nanoparticles and phenomenological model of this process developed on the basis of the phase-field theory. Keywords: carbon nanotubes, nanoparticles of catalyst, phase transitions, decomposition of supersaturated solid solutions.