Synthesis of uniform carbon micro-coils by using hybrid catalyst of Fe thin film and SnO2 powder

Carbon micro-coils (CMCs) with high yield have been synthesized by chemical vapor deposition (CVD) using hybrid catalyst. The hybrid catalysts consist of two forms, i.e. thin film catalyst and powered catalyst, which was selected. It was found that the prepared catalyst by the combination of Fe thin film and SnO₂ power exhibits the highest uniformity, which significantly results in uniform carbon micro-coils. The optimum condition for thickness of Fe thin film is 300 nm, and the size of SnO₂ powders is approximate 100 nm. The fiber diameter of the as-grown CMCs is determined by the size of the SnO₂ particles after treatment with Fe film by CVD. CMCs with controlled diameters have an average coil diameter of 3.36 μm, a fiber diameter of 385 nm, and a pitch of 1.82 μm. A 90% of yield of CMCs is achieved.