High-yield production of quasi-aligned carbon nanotubes by catalytic decomposition of benzene

High-yield production of quasi-aligned carbon nanotube (CNT) bundles is presented. Benzene was used as the precursor for this catalytic process at a moderate temperature of 650°C over γ-Al₂O₃-supported Fe-Ni alloy catalysts with different mole ratios. The maximum yield of high-quality CNTs per hour is even greater than 350% for the optimized catalyst. The products were characterized by thermal gravimetry/differential scanning calorimetry and high-resolution transmission electron microscopy. The results indicated that the products are well graphitized with tube diameters of about 20 nm. Three typical morphologies of the end parts of the CNTs were identified as the open end capped with an Fe-Ni catalyst, the open end without catalyst and the closed end, respectively. A hexagonal carbon-cluster-based growth for this synthesis is suggested.