Chemical Makeup and Hydrophilic Behavior of Graphene Oxide Nanoribbons after Low-Temperature Fluorination

详细信息    查看全文

• 作者：Rebeca Romero Aburto ; Lawrence B. Alemany ; Thomas K. Weldeghiorghis ; Sehmus Ozden ; Zhiwei Peng ; Aur茅lien Lherbier ; Andr茅s Rafael Botello M茅ndez ; Chandra Sekhar Tiwary ; Jaime Taha-Tijerina ; Zheng Yan ; Mika Tabata ; Jean-Christophe Charlier ; James M. Tour ; Pulickel M. Ajayan
• 刊名：ACS Nano
• 出版年：2015
• 出版时间：July 28, 2015
• 年：2015
• 卷：9
• 期：7
• 页码：7009-7018
• 全文大小：772K
• ISSN：1936-086X

文摘

Here we investigated the fluorination of graphene oxide nanoribbons (GONRs) using H₂ and F₂ gases at low temperature, below 200 掳C, with the purpose of elucidating their structure and predicting a fluorination mechanism. The importance of this study is the understanding of how fluorine functional groups are incorporated in complex structures, such as GONRs, as a function of temperature. The insight provided herein can potentially help engineer application-oriented materials for several research and industrial sectors. Direct ¹³C pulse magic angle spinning (MAS) nuclear magnetic resonance (NMR) confirmed the presence of epoxy, hydroxyl, ester and ketone carbonyl, tertiary alkyl fluorides, as well as graphitic sp²-hybridized carbon. Moreover, ¹⁹F鈥?sup>13C cross-polarization MAS NMR with ¹H and ¹⁹F decoupling confirmed the presence of secondary alkyl fluoride (CF₂) groups in the fluorinated graphene oxide nanoribbon (FGONR) structures fluorinated above 50 掳C. First-principles density functional theory calculations gained insight into the atomic arrangement of the most dominant chemical groups. The fluorinated GONRs present atomic fluorine percentages in the range of 6鈥?5. Interestingly, the FGONRs synthesized up to 100 掳C, with 6鈥?9% of atomic fluorine, exhibit colloidal similar stability in aqueous environments when compared to GONRs. This colloidal stability is important because it is not common for materials with up to 19% fluorine to have a high degree of hydrophilicity.