Improvement of Growth Yield of Multi-Walled Carbon Nanocoils by Mesoporous Materials and Sn Amount

Abstract

Multi-walled carbon nanocoils (MWCNCs) have been successfully synthesized by catalytic chemical vapor deposition (CVD) using Fe-Sn catalyst supported on mesoporous materials. Fe was supported on mesoporous materials in the ethanol solution of iron acetate, and Sn was deposited on the Fe-supported mesoporous materials using vacuum evaporation to form Fe-Sn nanoparticles. Zeolite and MCM-41 were used as a mesoporous material, and the length of Sn wire evaporated and reaction time were varied in the experiment. It was shown that zeolite with its smaller pore size worked better for MWCNCs growth than MCM-41 did. It is believed that the size of Fe-Sn catalyst nanoparticle was larger than that of the pores of zeolite and the catalyst nanoparticle stayed outside the pore, instead of entering into it. This makes carbon adsorption on catalyst nanoparticle easier during MWCNC synthesis. Evaporation of Sn for the formation of Fe-Sn catalyst resulted in a higher growth yield of MWCNCs than the previous catalyst supporting method that uses the acid solution of both Fe and Sn. Transmission electron microscopy observation revealed that MWCNCs grown have multi-walled graphitic layers (ca. 19 layers) with a hollow structure in the center of the tubes.