Probing the Thermal Deoxygenation of Graphene Oxide Using High-Resolution In Situ X-ray-Based Spectroscopies

A Ganguly, S Sharma, P Papakonstantinou, JWJ Hamilton

Research output: Contribution to journalArticle

624 Citations (Scopus)

Abstract

Despite the recent developments in graphene oxide due toits importance as a host precursor of graphene, the detailed electronicstructure and its evolution during the thermal reduction remain largelyunknown, hindering its potential applications. We show that a combina-tion of high-resolution in situ X-ray photoemission and X-ray absorptionspectroscopies offer a powerful approach to monitor the deoxygenationprocess and comprehensively evaluate the electronic structure of gra-phene oxide thin films at different stages of the thermal reduction process.It is established that the edge plane carboxyl groups are highly unstable,whereas carbonyl groups are more difficult to remove. The resultsconsistently support the formation of phenol groups through reaction of basalplane epoxide groups with adjacent hydroxyl groups at moderate degrees ofthermal activation (∼400 C). The phenol groups are predominant overcarbonyl groups and survive even at a temperature of 1000 C. For the first time, a drastic increase in the density of states (DOS) near theFermi level at 600 C is observed, suggesting a progressive restoration of aromatic structure in the thermally reduced graphene oxide.
LanguageEnglish
Pages17009-17019
JournalThe Journal of Physical Chemistry C
Volume115
DOIs
Publication statusPublished - 20 Jul 2011

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Graphite
Oxides
Spectroscopy
Phenol
X rays
Epoxy Compounds
Photoemission
Hydroxyl Radical
Restoration
Oxide films
Electronic structure
Chemical activation
Thin films
Hot Temperature
Temperature

Cite this

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Probing the Thermal Deoxygenation of Graphene Oxide Using High-Resolution In Situ X-ray-Based Spectroscopies. / Ganguly, A; Sharma, S; Papakonstantinou, P; Hamilton, JWJ.

In: The Journal of Physical Chemistry C, Vol. 115, 20.07.2011, p. 17009-17019.

Research output: Contribution to journalArticle

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AB - Despite the recent developments in graphene oxide due toits importance as a host precursor of graphene, the detailed electronicstructure and its evolution during the thermal reduction remain largelyunknown, hindering its potential applications. We show that a combina-tion of high-resolution in situ X-ray photoemission and X-ray absorptionspectroscopies offer a powerful approach to monitor the deoxygenationprocess and comprehensively evaluate the electronic structure of gra-phene oxide thin films at different stages of the thermal reduction process.It is established that the edge plane carboxyl groups are highly unstable,whereas carbonyl groups are more difficult to remove. The resultsconsistently support the formation of phenol groups through reaction of basalplane epoxide groups with adjacent hydroxyl groups at moderate degrees ofthermal activation (∼400 C). The phenol groups are predominant overcarbonyl groups and survive even at a temperature of 1000 C. For the first time, a drastic increase in the density of states (DOS) near theFermi level at 600 C is observed, suggesting a progressive restoration of aromatic structure in the thermally reduced graphene oxide.

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