Functionalization of primary amine groups to single-walled carbon nanotubes by reacting fluorinated SWCNTs with ammonia gas at a low temperature

• Published in: Carbon (New York) 2021-02, Vol.172, p.360-371
• Main Authors: Yokoyama, Koji, Sato, Yoshinori, Yamamoto, Masashi, Nishida, Tetsuo, Itoh, Takashi, Motomiya, Kenichi
• Format: Article
• Language: English
• Subjects: Ammonia; Atoms & subatomic particles; Capacitance; Carbon; Chemicals; Fluorination; Fluorine; Functionalization; Hydrazines; Low temperature; Nanotubes; Photoelectrons; Primary amine groups; Single wall carbon nanotubes; Single-walled carbon nanotubes; Temperature; Zeta potential
• ISSN: 0008-6223; 1873-3891
• DOI: 10.1016/j.carbon.2020.10.038

We functionalized primary amine groups (NH2-) to single-walled carbon nanotubes (SWCNTs) by reacting fluorinated SWCNTs with ammonia gas at a low temperature and characterized NH2-functionalized SWCNTs which were prepared by defluorinating the remaining fluorine groups via a hydrazine treatment. It is evident from the results of the Kaiser test and X-ray photoelectron spectroscopy that a few primary amine groups were functionalized onto the nanotubes. The average number of NH2 groups in the NH2-functionalized SWCNTs was 21.5 μmol/g. One primary amine group was functionalized per about 500 carbon atoms on the outermost surface of the bundled nanotube frame. The zeta potential of the SWCNTs was found to be +14 mV (pH = 3.0) and the specific capacitance of the NH2-SWCNTs was approximately 1.7 times higher than the hc-SWCNTs at a scan rate of 10 mV/s, which indicated the functionalization effect of the primary amine groups. [Display omitted]