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, N2 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 °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.

The catalytic activity of Co-MCM-41, which are characterised by XRD, N2 adsorption isotherms and DRS-UV spectroscopy, was tested for synthesis of carbon nanotubes (CNTs), which are confirmed by SEM, TEM and Raman spectroscopy. The uniform diameter of carbon nanotubes has found to be in the range of 25–30 nm. Figure optionsDownload as PowerPoint slide