ISSN print edition: 0366-6352 ISSN electronic edition: 1336-9075 Registr. No.: MK SR 9/7 Published monthly

Single-walled carbon nanotubes: synthesis and quantitative purification evaluation by acid/base treatment for high carbon impurity elimination

Afsoon Aghaei, Maryam Shaterian, Hassan Hosseini-Monfared, and Afsaneh Farokhi

Department of Chemistry, Faculty of Science, University of Zanjan, Zanjan, Iran

E-mail: afsoon.aghayi@znu.ac.ir

Received: 10 March 2022  Accepted: 7 September 2022

Abstract:

Purification of carbon nanotubes by chemical oxidation method and their efficiency was considered a function of the position and size of the catalyst residues and thus the morphology of the tubes. Reproducible, low loss and high-yield purification procedure for single-walled carbon nanotubes (SWCNTs) was expanded by acid–base treatment with nitric acid and sodium hydroxide. Herein, we have described high SWCNTs growth and selectivity due to optimal metal-support interaction in iron oxide nanoparticles/alumina (Fe₂O₃/Al₂O₃) catalyst by chemical vapor deposition technique under CH₄ gas. Then, SWCNTs obtained over metallic ccatalyst can be efficiently purified by liquid oxidation method. The process involves the NaOH treatment at temperatures of 100 °C for 6 h, which remove the support particles, and an acid treatment with HNO₃ for 1 h, which etches away the catalytic metals. The quality of the final material was verified by Fourier transform infrared, Raman spectroscopy, energy-dispersive X-ray (EDS), thermogravimetric analysis and transmission electron microscopy. The results showed that the amorphous carbon and iron catalysts were completely removed without any damage to the walls of structure. Our research shows that this method can greatly enhance the selectivity of carbonaceous impurities removal.

Keywords: Single-walled carbon nanotube; Fe2O3/Al2O3; Purification; Liquid oxidation; NaOH/HNO3

Full paper is available at www.springerlink.com.

DOI: 10.1007/s11696-022-02478-5

Chemical Papers 77 (1) 249–258 (2023)