Synthesis of carbon nanotubes using Fe-Mo/Al2O3 bimetallic catalyst by CVD method

Carbon nanotubes (CNTs) are interesting materials in view of their wide range of applications in hydrogen storage, chemical sensor, catalytic support, biochemical applications and field emission. Such tremendous applications are due to unique geometry, high chemical stability, high mechanical strength and excellent thermal and electrical conductivity. Various synthesis methods such as arc discharge, laser ablation, plasma enhanced chemical vapour deposition and chemical vapour deposition (CVD) is currently practiced. Among these methods, CVD is one of the most commonly used techniques for laboratory and commercial scale synthesis of CNTs. Individually Fe, Co and Ni are commonly employed as catalyst for the formation of CNTs by CVD technique. However, bimetallic catalysts like Fe-Mo, Co-Mo, Co-Ni and Fe-Co have also been effectively used with the use of solid scanning electron microscopy (SEM) images. The SEM images show that the increase in percentage of Molybdenum has effect in the growth of carbon nanotubes. Though the sample shows CNT like structure, the presence of different sizes of CNTs together with the agglomeration of amorphous carbon and catalyst indicates uneven dispersion of the active catalyst. But the addition of Mo helps in the dispersion of the Fe catalyst which is responsible for the uniform growth of CNTs in case of Fe-Mo catalyst. It was also found that the addition of molybdenum improves the growth of carbon nanotubes as well as the yield of Carbon nanotubes.