Chemical vapor deposition, Catalyst, Carbon nanocoils, High efficient growth
Abstract: Carbon nanocoils (CNCs) were prepared by thermal chemical vapor deposition (CVD) using a Fe and Sn containing solution as the catalyst predecessor. The solutions of Fe2(SO4)3/SnCl2, FeCl3/SnCl2 and Fe(NO3)3/SnCl2 with the mol ratios of 3:0.1 to 3:1 were used as catalysts. Comparing the catalysts in different composition ratios with the grown deposits after CVD, we found that the optimum mol ratio between Fe and Sn is 6:0.1. It is noted that the catalyst combination of Fe2(SO4)3 /SnCl2 obviously increases the quantity of the grown carbon deposits indicating that it has the largest catalytic activity among the three kinds of combinations. Large surface area of catalyst films formed by release of SO3 from the decomposition of Fe2(SO4)3 over the temperature of 480 °C is very good for the carbon nanocoils growth and the introduction of sulfide impurities are the key factors leading to the high efficient growth for carbon nanocoils. It is known that Fe-additions lead to the growth of carbon nanotubes or nanofibers, while Sn induces their helical growth and a little sulfur impurities may induce the efficient growth of carbon nanocoils.
