Department of Chemistry
Large-scale synthesis, characterization and microwave absorption properties of carbon nanotubes of different helicities
Carbon nanotubes of high helicity (H-HCNTs, Sample A) have been synthesized in large-scale by pyrolysis of acetylene at 450 °C over Fe nanoparticles derived from coprecipitation/hydrogen reduction method. With controlled introduction of hydrogen during acetylene pyrolysis, CNTs of low helicity (L-HCNTs, Sample B) and worm-like CNTs (Sample C) were obtained in large quantities. The yields of the CNTs products are high, especially that of H-HCNTs (ca. 7474%). The complex permittivity and permeability of Composites A, B, and C that contain Samples A, B and C (30 wt%) were measured in the 2-18 GHz frequency range. Good absorption of electromagnetic wave (reflection loss<-20 dB) was observed in the 7.18-10.68 and 7.5-10.7 GHz range over Composites B and C (2.0-3.0 mm thickness), respectively. Thus, through the suggested route, CNTs can be produced easily and selectively in large quantities. The lightweight materials can be utilized for microwave absorption. © 2009 Elsevier Inc. All rights reserved.
Carbon nanotubes, Complex permeability, Complex permittivity, Reflection loss
Source Publication Title
Journal of Solid State Chemistry
Qi, Xiaosi, Yi Yang, Wei Zhong, Yu Deng, Chaktong Au, and Youwei Du. "Large-scale synthesis, characterization and microwave absorption properties of carbon nanotubes of different helicities." Journal of Solid State Chemistry 182.10 (2009): 2691-2697.