Growth of carbon nano-structures in ceramic materials

Tailored pore size mesoporous silica, incorporating different concentrations of transition metal-based catalysts, has been used as platforms for the growth of carbon nanotubes by the catalytic chemical vapor deposition method. Both compositional surface analysis by EDX/SEM combinatory techniques and thermo gravimetric analysis were employed to characterize the samples prior to CNT growth. The CNTs produced were characterized using Raman Spectroscopy, high resolution SEM and TEM. Raman spectroscopy showed good quality highly graphitic CNTs and indicated the presence of crystalline graphitic carbon, microcrystalline graphite as well as amorphous carbon in the carbon nanotube layer. TEM and HI RES SEM images matched diameters of the carbon nanotubes to the corresponding pores of the matrices. Comparison of the carbon nanotube diameters to porous properties of the mesoporous silica confirmed probable growth from within the pores. The density of the carbon nanotubes was found to be high for higher metal concentrations for the same pore diameters. Fe and Co were confirmed to be better catalysts, compared to Ni, for growth of carbon nanotubes by the catalytic chemical vapour method.