Multiwalled carbon nanotubes synthesis with high yield utilizing Pt/Al-MCM-41 via catalytic chemical vapour deposition technique

Multiwalled carbon nanotubes (MWNTs) were synthesized over Pt impregnated Al-MCM-41 catalyst by decomposition of acetylene and characterized by XRD and nitrogen sorption isotherm to study the mesophase nature of the material. The optimum temperature and flow rate of the carbon source for CNTs synthesis are 800 °C and 60 mL/min, respectively, within a short reaction period, typically 10 min. Moreover, longer reaction time (i.e. 30 min) favours the formation of more amorphous carbon. When the reaction time is reduced to less than 10 min, formation of amorphous carbon is greatly suppressed by the high yield of MWNTs (85%). The products obtained from the decomposition of acetylene over these catalysts were characterized by TGA, SEM, TEM and Raman spectroscopy. The TEM analysis reveals that CNTs are free from amorphous carbon, whereas Raman spectrum shows two prominent peaks at 1,327 and 1,594 cm⁻¹ as the tangential modes of CNTs. As a conclusion, Pt/Al-MCM-41 is an effective template for MWNTs synthesis using acetylene as a carbon source.