Catalytic influence of mesoporous Co-MCM-41 molecular sieves for the synthesis of SWNTs via CVD method

Mesoporous Co-MCM-41 molecular sieves with various Si/Co ratios: 25, 50, 75 and 100 were synthesised by direct incorporation of cobalt into the framework through hydrothermal method. The Co-MCM-41 was characterised by various physico-chemical techniques such as XRD, NZ adsorption isotherms and DR UV-vis spectroscopy. The efficiency of the catalyst was tested for the production of carbon nanotubes (CNTs) using acetylene as a carbon precursor at 750 degrees C. Using our optimized conditions for this system, Co-MCM-41 (100) catalytic template showed the best results with particularly high selectivity for SWNT. TEM and SEM image shows the formation of well-graphitised single walled carbon nanotubes (SWNTs) with a diameter of 30 nm and it was further confirmed by Raman spectrum, where spectrum shows SWCNTs in the vicinity of the D-band and G-band at 1302 and 1607 cm(-1), respectively. The catalytic template maintains its crystallinity after successive reaction, which suggests that Co-MCM-41 is a very stable template for producing SWNT under harsh conditions. (c) 2006 Elsevier B.V All rights reserved.