Mono-, Bi-, and Trimetallic Catalysts for the Synthesis of Multiwalled Carbon Nanotubes Based on Iron Subgroup Metals

Formation features of mono- (Fe, Co, Ni), bi- (Fe-Co, Fe-Ni, Co-Ni), and trimetallic (Fe-Co-Ni) catalysts for the synthesis of multiwalled carbon nanotubes (MWCNTs) prepared by the method of polymerized complex precursors are revealed. It is shown that initial bimetallic and trimetallic catalysts occur in a wide range of phases with spinel structure consisting of different mixed metal oxides (Me(II)Me(III)2O4). The influence of the active component composition and the catalyst activation conditions on their activity in the reaction of MWCNT synthesis is determined. MWCNTs with specific structural characteristics, a narrow diameter distribution and a relatively low degree of defectiveness, can be obtained by varying the composition of the catalyst active component.