Photonic crystals in biology

Poster Session, Tuesday, June 15
Theme A1 - B702
Electrochemical Synthesis of Ordered Graphene Structures
1 *, Duygu Ekinci 2 , Ümit Demir 2
1 Atatürk University, Erzurum Vocational and Training School, Dept. of Chemistry, Erzurum, Turkey
2 Atatürk University, Faculty of Science, Dept. of Chemistry, Erzurum, Turkey
Abstract-We report an electrochemical method for the formation of ordered graphene structures on Au (111) electrode by the
electrochemical reduction of graphite oxide (GO). The electrochemical reduction of GO was carried out by two ways: i- direct
electrochemical reduction from the aqueous solution of GO and ii- the electrochemical reduction of adsorbed GO onto Au substrate. The
characterization of reduced GO (RGO) was performed by Fourier transform infrared spectroscopy (FT-IR), scanning tunneling microscopy
(AFM-STM ), X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS).
Graphene is a single layer of carbon atoms in a closely
packed honeycomb two-dimensional (2D) lattice [1].
Graphene is used in nanocomposites and microelectrical
devices such as field-effect transistors, ultrasensitive
sensors, ultracapacitors etc, due to its unique electronic
properties [2]. In literature, the synthesis of graphene is
generally achieved with the chemical reduction in the
presence of reducing agent such as hydroquinone, NaBH 4
and hydrazine. In this study, graphene structures on Au
(111) are also electrochemically synthesized from graphite
oxide (GO) which contains oxygen functional groups such
as epoxides, -OH and –COOH groups [3].
Figure 1. Cyclic voltammograms of GO in aqueous solutions
containing 0.1 M KNO 3 .
Figure 2. (a) STM images of graphene layers, (b) Atomic scale
STM image of graphene.
*Corresponding author: hdogan@atauni.edu.tr
[1] G. Wang, J. Yang, J. Park, X. Gou, B. Wang, H. Liu and J.
Yao, J. Phys. Chem. C, 112 (22), 8192 (2008). [2] G.K.
Ramesha and S. Sampath, J. Phys. Chem. C Lett., 113, 7985
(2009).
[3] Z. Wang, X. Zhou, J. Zhang, F. Boey and H. Zhang, J. of
Phys. Chem. C Lett., 113, 14071 (2009).
[4] T.S. Sreeprasad, A.K. Samal and T. Pradeep, J. Phys. Chem.
C., 113, 1727 (2009).
[5] H.Guo, X. Wang, Q. Qian, F. Wang and X. Xia, ACS Nano, 3
(9), 2653 (2009).
[6] E. Stolyarova, D. Stolyarov,L. Liu, K.T. Rim, Y. Zhang, M.
Han, M Hybersten, P. Kim and G. Flynn, J. Phys. Chem. C, 112,
6681 (2008).
GO was prepared from graphite powder by using a
modified Hummer method [4]. Cyclic voltammetry
technique was used to determine the electrochemical
reduction potentials of GO (Figure 1). Synthesized GO
were reduced by two methods. First, GO was directly
reduced from a solution (pH:2) containing GO on Au
electrode at -500 mV. Secondly, GO was adsorbed onto
Au substrate in pH=2 buffer solution and then was reduced
electrochemically in an aqueous solution containing 0,1 M
KNO 3 .
GO reduced in solution phase, was characterized by X-
ray diffraction (XRD), X-ray photoelectron spectroscopy
(XPS) and Fourier transform infrared spectroscopy (FT-
IR). XRD patterns showed that the structure of GO is
changed to (002) crystal structure of graphite [5].
Furthermore the C1s XPS spectra of GO and graphene
were confirmed the formation of the RGO.
Morphological investigations done by STM and AFM
indicate the formation of the ordered graphene
nanostructures (Figure 2). Atomic scale STM image of the
GO films on Au (111) electrode shows that the atomic
structures of graphene has hexagonal carbon atoms and the
distance between the atoms is about 2.5 Å, which is in
good agreement with literature data [6].
6th Nanoscience and Nanotechnology Conference, zmir, 2010 295