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Dopping Effects on Multiwalled Carbon Nanotubes: Influence of Different Acid Treatments

Sara Costa ,  Ewa Borowiak - Paleń 

Szczecin University of Technology, Institute of Chemical and Environment Engineering, Szczecin 70-322, Poland

Abstract

In the present study we report the surface modification of multiwalled carbon nanotubes (MWCNT) using HCl, HNO3 and H2SO4. Acids are commonly used in purification procedures to remove catalyst particles from the raw material. However, it is known that MWCNT upon acid treatment have many surface functionalized groups or intercalate within the walls, modifying their electronic properties [1]. Several studies on doping of different CNT have been previously developed, however none of them provide a comparison between different acids. 

Here, we present a comparative study between samples of MWCNT modified with the most common acids used in the purification of carbon materials and the influence of the treatment time on their properties. The samples were analyzed via Raman and Infrared (IR) spectroscopies. While the first method is a very helpful tool to understand the electronic modifications of the carbon nanotubes (CNT), the second one supports to identify the functional groups attached on the MWCNT surface (such as carboxylic and nitrile groups).  

Data show in this contribution proved that different acids treatments result in different changes in the bands of the Raman spectra. HNO3 influence the most in the disorder band (D band), while H2SO4 and HCl are responsible for affecting more the graphite band (G band) as well as the two-phonon second order raman band (G’ band). The treatment time showed to be directly correlated with the shift of the different Raman bands.

[1] EB Barros et al., Physical Review B 76 (2007) 045425

 

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Related papers

Presentation: Poster at E-MRS Fall Meeting 2008, Symposium A, by Sara Costa
See On-line Journal of E-MRS Fall Meeting 2008

Submitted: 2008-05-12 14:05
Revised:   2009-06-07 00:48