Chinese Journal of Catalysis

Chinese Journal of Catalysis ›› 2014, Vol. 35 ›› Issue (6): 864-868.DOI: 10.1016/S1872-2067(14)60107-8

• Articles • Previous Articles     Next Articles

A selective way to create defects by the thermal treatment of fluorinated double walled carbon nanotubes

Hiroyuki Muramatsua, Kazunori Fujisawaa, Yong-Il Koa, Kap-Seung Yangb, Takuya Hayashia, Morinobu Endoc, Cheol-Min Yangd, Yong Chae Jungd, Yoong Ahm Kimb   

  1. a Faculty of Engineering, Shinshu University, 4-17-1 Wakasato, Nagano 380-8553, Japan;
    b School of Polymer Science and Engineering, Chonnam National University, 77 Yongbong-ro, Buk-gu 500-757, Gwangju, Korea;
    c Institute of Carbon Science and Technology, Shinshu University, 4-17-1 Wakasato, Nagano 380-8553, Japan;
    d Institute of Advanced Composite Materials, Korea Institute of Science and Technology, Chudong-ro 92, Bongdong-eup, Wanju-gun, Jeonbuk 565-905, Korea
  • Received:2014-03-13 Revised:2014-04-02 Online:2014-05-30 Published:2014-06-03

PDF (PC)

600

Abstract:

Nanoscale defects in the outer tube to preserve the electrical and optical features of the inner tube can be engineered to exploit the intrinsic properties of double walled carbon nanotubes (DWCNTs) for various promising applications. We demonstrated a selective way to make defects in the outer tube by the fluorination of DWCNTs followed by the thermal detachment of the F atoms at 1000℃ in argon. Fluorinated DWCNTs with different amounts of F atoms were prepared by reacting with fluorine gas at 25, 200, and 400℃ that gave the stoichiometry of CF0.20, CF0.30, and CF0.43, respectively. At the three different temperatures used, we observed preservation of the coaxial morphology in the fluorinated DWCNTs. For the DWCNTs fluorinated at 25 and 200℃, the strong radial breathing modes (RBMs) of the inner tube and weakened RBMs of the outer tube indicated selective fluorine attachment onto the outer tube. However, the disappearance of the RBMs in the Raman spectrum of the DWCNTs fluorinated at 400℃ showed the introduction of F atoms onto both inner and outer tubes. There was no significant change in the morphology and optical properties when the DWCNTs fluorinated at 25 and 200℃ were thermally treated at 1000℃ in argon. However, in the case of the DWCNTs fluorinated at 400℃, the recovery of strong RBMs from the inner tube and weakened RBMs from the outer tube indicated the selective introduction of substantial defects on the outer tube while preserving the original tubular shape. The thermal detachment of F atoms from fluorinated DWCNTs is an efficient way to make highly defective outer tubes for preserving the electrical conduction and optical activity of the inner tubes.

Key words: Double walled carbon nanotube, Fluorination, De-fluorination, Defect engineering, Raman spectroscopy