Evidence of graphitic AB stacking order of graphite oxides.
Graphite oxide (GO) samples were prepared by a simplified Brodie method. Hydroxyl, epoxide, carboxyl, and some alkyl functional groups are present in the GO, as identified by solid-state 13C NMR, Fourier-transform infrared spectroscopy, and X-ray photoemission spectroscopy. Starting with pyrolytic graphite (interlayer separation 3.36 A), the average interlayer distance after 1 h of reaction, as determined by X-ray diffraction, increased to 5.62 A and then increased with further oxidation to 7.37 A after 24 h. A smaller signal in 13C CPMAS NMR compared to that in 13C NMR suggests that carboxyl and alkyl groups are at the edges of the flakes of graphite oxide. Other aspects of the chemical bonding were assessed from the NMR and XPS data and are discussed. AB stacking of the layers in the GO was inferred from an electron diffraction study. The elemental composition of GO prepared using this simplified Brodie method is further discussed.
Jeong
Hae-Kyung
HK
BK21 Physics Division, Institute of Basic Science, Center for Nanotubes and Nanostructured Composites, Sungkyunkwan University, Suwon 440-746, Korea. outron@skku.edu
Lee
Yun Pyo
YP
Lahaye
Rob J W E
RJ
Park
Min-Ho
MH
An
Kay Hyeok
KH
Kim
Ick Jun
IJ
Yang
Cheol-Woong
CW
Park
Chong Yun
CY
Ruoff
Rodney S
RS
Lee
Young Hee
YH