Comparative Study of SWCNT Fluorination by Atomic and Molecular Fluorine

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• 作者：Wei Zhang ; Pierre Bonnet ; Marc Dubois ; Christopher P. Ewels ; Katia Gu茅rin ; Elodie Petit ; Jean-Yves Mevellec ; Lo茂c Vidal ; Dimitri A. Ivanov ; Andr茅 Hamwi
• 刊名：Chemistry of Materials
• 出版年：2012
• 出版时间：May 22, 2012
• 年：2012
• 卷：24
• 期：10
• 页码：1744-1751
• 全文大小：535K
• 年卷期：v.24,no.10(May 22, 2012)
• ISSN：1520-5002

文摘

Single-wall carbon nanotubes (SWCNTs) are fluorinated around 200 掳C with molecular fluorine (F₂) and xenon difluoride (XeF₂) as fluorination agents. In this latter case, fluorination is carried out by atomic fluorine F鈥?/sup> generated by the thermal decomposition of gaseous XeF₂ on the nanotube surface. XeF₂ treatment results in stoichiometries from CF_0.05 to CF_0.32, and F₂ treatment gives compositions in the range CF_0.04 and CF_0.37. Transmission electronic microscopy (TEM), solid state Nuclear Magnetic Resonance (NMR), Raman scattering and Optical Absorption (AO) studies demonstrate that different fluorination mechanisms occur using molecular fluorine (F₂) and atomic fluorine (F鈥?/sup>). Atomic fluorine results in less sample damage and a more homogeneous fluorine distribution over the SWCNT surface than F₂. This is explained via DFT calculations showing that HF catalyzed F₂ deposition necessarily leads to highly fluorinated domain formation whereas F鈥?/sup> addition occurs spontaneously at the initial species arrival site.

Keywords:

carbon nanotubes; fluorination; ¹⁹F NMR; Raman diffusion; density functional theory