Synthesis of Multiwall Carbon Nanotubes in the Pore System and/or on the Outer Surface of Mesoporous MCM-41 Structures of Various Morphology

Abstract

Multiwall carbon nanotubes were synthesized either on the outer surface of iron containing mesoporous silicates using catalytic chemical vapor deposition (CCVD) or in the pore system of morphologically different mesoporous materials (hexagonal or spherical shapes) with graphitization of the template molecules. Transmission electron microscopy (TEM) study shows that the CCVD method resulted in long, bent and well graphitized carbon nanotubes on impregnated samples irrespective to the morphology of the silicate. Isomorphously substituted spherical MCM-41 with low Si/Fe ratio was found to be active catalysts for carbon nanotube production in CCVD as well. Synthesis of MWNTs with graphitization of template molecules in the pores of MCM-41 was successful in hexagonal MCM-41 samples irrespective that they contain or not iron in the silicate framework. Carbon nanotube formation was not observed in spherical derivatives of these samples during the graphitization process.