变径反应器浮游催化裂解法制备双壁碳纳米管

ouble-walled carbon nanotubes (DWCNTs) have been synthesized by a floating catalytic chemical vapor deposition method with ferrocene as catalyst precursor, xylene as carbon sources and sulfur as additive, which was conducted in a reactor with varied diameter. The as-grown products were characterized by scanning electron microscope (SEM), transmission electron microscope (TEM), Raman spectrometer, thermo gravimetry-differential thermal analysis (TGA-DTA). The results showed that the carrier gas velocity in different parts of the reactor can be adjusted effectively, by making use of a diameter-varied reactor made of two quartz tubes with different diameters. Under the optimized conditions, the pyrolysis efficiency of carbon sources and the synthesis of DWCNTs have been improved. It is also found that the S/Fe ratio and the flow rate have a significant influence on the morphology and purity of the carbon nanotubes. The reason for the zone selectivity at different flow rate and the influence of the diameter-changed structure on the growth of DWCNTs were discussed as well. It is believed that the diameter-varied reactor may become a feasible route to the mass and continuous production of DWCNTs.