EVALUATION OF THE EFFECT OF CATALYST TEXTURAL PROPERTIES ON EFFECTIVE SYNTHESIS OF CARBON NANOTUBES

Abstract

Co – Mo / MgO catalysts of same content but different textural properties were prepared through manipulation of foaming agents (ethylene glycol, citric acid and polyethylene glycol 200) in a sol–gel method. Experimental results indicated that surface area and pore size of the catalysts were equally important in the synthesis of carbon nanotubes (CNTs) from catalytic chemical vapor deposition. It was found that the catalysts with high surface area and large pore size were the main criteria for high yield synthesis of CNTs of better graphitized wall structure. High surface area helped in the dispersion of active metals, thus increasing the number of active sites for nucleation and growth of CNTs. Meanwhile, larger pore size facilitated better mass transfer between the inner pore and the exterior reaction atmosphere, and it provided a larger space for unrestricted growth of CNTs. In the present work, we demonstrated that the Co – Mo / MgO catalysts prepared by citric acid possessed both larger average pore size and higher surface area, which provoked the synthesis of better quality (graphitized) CNTs in high yield.