TY - JOUR
T1 - Towards the understanding of the graphene oxide structure
T2 - How to control the formation of humic-and fulvic-like oxidized debris
AU - Rodriguez-Pastor, Iluminada
AU - Ramos-Fernandez, Gloria
AU - Varela-Rizo, Helena
AU - Terrones, Mauricio
AU - Martin-Gullon, Ignacio
N1 - Funding Information:
The authors thank the Government of Spain, Ministry for Economy and Competiveness , for financial support of project CTQ2013-44213-R, and Generalitat Valenciana for projects PROMETEOII/2014/007 and ISIC/2012/008. IRP thanks the Government of Spain, Ministry of Science and Education, for PhD Scholarship in the FPU program.
Publisher Copyright:
© 2014 Elsevier Ltd. All rights reserved.
PY - 2015
Y1 - 2015
N2 - Former structural models of graphene oxide (GO) indicated that it consists of graphene-like sheets with oxygen groups, and no attention was paid to the resulting sheet size. We now provide evidence of the complex GO structure consisting of large and small GO sheets (or oxidized debris). Different oxidation reactions were studied. KMnO4 derived GO consists of large sheets (20-30 wt.%), and oxidized debris deposits, which are formed by humicand fulvic-like fragments. Large GO sheets contain oxygen groups, especially at the edges, such as carbonyl, lactone and carboxylic groups. Humic-like debris consists of an amorphous gel containing more oxygenated groups and trapped water molecules. The main desorbable fraction upon heating is the fulvic-like material, which contains oxygen groups and fragments with high edge/surface ratio. KClO3 in HNO3 or the Brodie method produces a highly oxidized material but at the flake level surface only; little oxidized debris and water contents are found. It is noteworthy that an efficient basal cutting of the graphitic planes in addition to an effective intercalation is caused by KMnO4, and the aid of NaNO3 makes this process even more effective, thus yielding large monolayers of GO and a large amount of humic-and fulvic-like substances.
AB - Former structural models of graphene oxide (GO) indicated that it consists of graphene-like sheets with oxygen groups, and no attention was paid to the resulting sheet size. We now provide evidence of the complex GO structure consisting of large and small GO sheets (or oxidized debris). Different oxidation reactions were studied. KMnO4 derived GO consists of large sheets (20-30 wt.%), and oxidized debris deposits, which are formed by humicand fulvic-like fragments. Large GO sheets contain oxygen groups, especially at the edges, such as carbonyl, lactone and carboxylic groups. Humic-like debris consists of an amorphous gel containing more oxygenated groups and trapped water molecules. The main desorbable fraction upon heating is the fulvic-like material, which contains oxygen groups and fragments with high edge/surface ratio. KClO3 in HNO3 or the Brodie method produces a highly oxidized material but at the flake level surface only; little oxidized debris and water contents are found. It is noteworthy that an efficient basal cutting of the graphitic planes in addition to an effective intercalation is caused by KMnO4, and the aid of NaNO3 makes this process even more effective, thus yielding large monolayers of GO and a large amount of humic-and fulvic-like substances.
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U2 - 10.1016/j.carbon.2014.12.027
DO - 10.1016/j.carbon.2014.12.027
M3 - Article
AN - SCOPUS:84922224134
SN - 0008-6223
VL - 84
SP - 299
EP - 309
JO - Carbon
JF - Carbon
IS - 1
ER -