Eigler S, Dotzer C, Hof F, Bauer W, Hirsch A (2013)
Publication Type: Journal article, Original article
Publication year: 2013
Original Authors: Eigler S., Dotzer C., Hof F., Bauer W., Hirsch A.
Publisher: Wiley-VCH Verlag
Book Volume: 19
Pages Range: 9490-9496
Journal Issue: 29
The structure of graphene oxide (GO) is of crucial importance for its chemical functionalization. However, the sulfur content present in GO prepared by Hummers' method has only been addressed by a few authors so far. It has been reported that hydrolysis of sulfur species takes place and that stable sulfonic groups are present in graphite oxide. In this manuscript, in contrast to earlier reports, sulfate species are identified that are covalently bound to GO and still present after extensive aqueous work-up. Additionally, we exclude the possibility that sulfonic groups are present in GO as major species after aqueous work up. Our results are based on bulk characterization of graphene oxide by thermogravimetry and subsequent analysis of the decomposition products using mass spectroscopy and infrared spectroscopy. Up to now, the combustion temperature between 200 and 300°C remained almost unaddressed. In a temperature dependant experiment we reveal two main decomposition steps that differ in temperature and that are closely related to the sulfur species in GO. While the decomposition, between 200 and 300°C, is related to the degradation of organosulfate, the other one, between 700 and 800°C, is assigned to the pyrolysis of inorganic sulfate. Furthermore, organosulfate is to some extent responsible for the reactivity of GO. Therefore, the structural model of GO was extended by adding organosulfate in addition to epoxy and hydroxyl groups, which are predominantly covalently bound above and below the carbon skeleton. Furthermore, the identification of organosulfate groups beneath epoxy groups makes new molecular architectures feasible and can be used to explain the properties of GO in various applications. Sulfur on the surface: Organosulfate was found to be an essential part of the structure of graphene oxide (see figure), which was prepared according to Hummers' protocol. These organosulfate groups play an important role in the immobilization of adsorbed species and influence the chemical reactivity of the graphene oxide. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.
APA:
Eigler, S., Dotzer, C., Hof, F., Bauer, W., & Hirsch, A. (2013). Sulfur species in graphene oxide. Chemistry - A European Journal, 19(29), 9490-9496. https://doi.org/10.1002/chem.201300387
MLA:
Eigler, Siegfried, et al. "Sulfur species in graphene oxide." Chemistry - A European Journal 19.29 (2013): 9490-9496.
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