Synthesis of Single Walled Carbon Nanotubes Using Cobalt Grafted in MCM-41 as Catalyst
L.F. Giraldo, B.L. López, G.L. Haller
Universidad de Antioquia, CO
Keywords: carbon nanotubes, grafting, catalyst
Abstract:In this work (SWCNTs) have been synthesized by high pressure CO decomposition using cobalt grafted in MCM41 by means of grafting method employing cobalt (II) acetylacetonate. The reduction temperature of the metal species of this catalyst and their physical properties characterized by XRD, nitrogen physisorption and temperature reduction programmed are compared with those of the catalyst prepared by in-situ incorporation. The SWCNTs are characterized by RAMAN spectroscopy, transmission electron microscopy (TEM) and thermogravimetrical analysis (TGA). The results show a good and uniform dispersion of cobalt metallic particles on the MCM-41. The onset of reduction temperatures for the metal species as well as the pores size distribution of mesoporous catalysts decreased linearly with increasing metal concentration. The ration between the G and D intensity bands for the carbon nanotubes remains constant with the metal concentrations used, however, the carbon yield increased linearly with the metal load, without evidence of amorphous carbon as it is corroborated by TEM and TGA. The results also showed that a better yield for the SWCNTs synthesis is obtained on the catalyst prepared by grafting in comparison with the catalysts prepared by in-situ incorporation, which is an important alternative in the production of SWCNTs in a bigger scale.