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

• Legal notice:
  

  Copyright (c) Pielaszek Research, all rights reserved.
  The above materials, including auxiliary resources, are subject to Publisher's copyright and the Author(s) intellectual rights. Without limiting Author(s) rights under respective Copyright Transfer Agreement, no part of the above documents may be reproduced without the express written permission of Pielaszek Research, the Publisher. Express permission from the Author(s) is required to use the above materials for academic purposes, such as lectures or scientific presentations.
  In every case, proper references including Author(s) name(s) and URL of this webpage: https://science24.com/paper/15717 must be provided.

1. ZnFe₂O₄/ZnO core-shell particles obtained by coprecipitation route
2. Resonance Raman study on carbon nanotubes formation and characterisation
3. Studies on preparation and characterisation of the carbon nanoforms