Effect of Hydrogen Fluoride Addition and Synthesis Temperature on the Structure of Double‐Walled Carbon Nanotubes Fluorinated by Molecular Fluorine

• Published in: physica status solidi (b) 2018-01, Vol.255 (1), p.n/a
• Main Authors: Fedoseeva, Yuliya V., Dubois, Marc, Flahaut, Emmanuel, Vilkov, Oleg Yu, Chuvilin, Andrey, Asanov, Igor P., Okotrub, Alexander V., Bulusheva, Lyubov G.
• Format: Article
• Language: English
• Subjects: Chemical and Process Engineering; double‐walled carbon nanotubes; Engineering Sciences; fluorination; Materials; NEXAFS; X‐ray photoelectron spectroscopy
• ISSN: 0370-1972; 1521-3951
• DOI: 10.1002/pssb.201700261

Double‐walled carbon nanotubes (DWCNTs) have been fluorinated by pure molecular fluorine (F2) at room temperature or 200 °C and a mixture of F2 with hydrogen fluoride (HF) at 200 °C that resulted in products with compositions of CF0.12, CF0.39, and CF0.53 as determined by X‐ray photoelectron spectroscopy. The differences in the structures of three kinds of fluorinated DWCNTs were revealed using transmission electron microscopy, Raman scattering, and near‐edge X‐ray absorption fine structure (NEXAFS) spectroscopy. Quantum‐chemical modeling of the NEXAFS F K‐edge spectra detected a change in the fluorine pattern with the increase of the F2 treatment temperature. The presence of HF in fluorine gas was found to accelerate the fluorination process and cause a partial destruction of outer shells of the DWCNTs. Schematic structures of the fluorinated DWCNTs prepared by treatment with pure F2 at 200 °C for 2 h (left) and F2 mixed with HF for 10 min at 200 °C (right). The presence of HF in fluorine gas is found to accelerate the fluorination process and cause a partial destruction of outer shells of the DWCNTs.