Supplementary Material
X-ray Photoelectron Spectroscopic Signatures of Graphene Oxide
Wenhua Zhang, Vincenzo Carravetta, Zhenyu Li, Yi Luo, and Jinlong Yang
Email: zyli@ustc.edu.cn
1. Experimental XPS spectra
(a)
(b)
Figure S1. The experimental XPS spectra by (a) Jeong et al. [1] and (b) Szabo et al. [2]. Based
on the height of the sp2 peak, the degree of oxidation should be PG < GO2 < GO1 in (a) and
GO-1 < GO-2 < GO-3 < GO-4 in (b)
2. Test results for alanine and tryptophan
alanine-I
alanine-IIa
tryptophan-1
tryptophan-2
Figure S2. Geometric structures of different conformers of alanine and tryptophan.
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Table S1. C 1s, N 1s, and O 1s core chemical shifts of alanine.
Core Level
C 1s
N 1s
O 1s
Exp. (eV)
alanine-I (eV)
alanine-IIa (eV)
Ref.[3]
Ref.[3] our results Ref.[3] our results
0.0
0.0
0.0
0.0
0.0
1.2
1.5
1.2
1.5
1.3
4.0
5.0
3.7
4.3
3.3
0.0
0.7
0.0
0.0
1.8
0.0
1.9
0.0
0.0
2.1
assignment
-CH3
-C-NH2
-COOH
0.9
0.9
H-donor
H-acceptor
0.0
1.7
0.0
1.5
-O=C
-O-H
Table S2. C 1s, N 1s, and O 1s core chemical shifts of tryptophan.
Core Level Exp. (eV) CCS (eV)
Ref. [4]
C1s
N1s
O1s
289.85
0.0
290.72
0.87
291.70
294.60
1.85
4.75
404.70
405.25
405.70
537.70
539.52
theoretical results (eV)
assignment
conformer-1 conformer-2
0.0
0.0
0.1
0.1
0.3
0.3
0.9
1.0
1.1
2.0
3.9
0.0
0.0
0.1
0.2
0.3
0.3
1.0
1.0
1.2
2.1
3.3
C-ring(6)
0.00
0.55
1.00
0.0
0.4
0.0
1.0
N-indol
N-donor
N-acceptor
0.00
1.82
0.0
1.6
0.0
2.0
O=C
O-H
2
C-ring(5),Cβ
Cα
COOH
3. Other models used in periodic calculations
(a)
(b)
(c)
(d)
Figure S3. (a) A zigzag edge model with a COOO group (1D-2), (b) an armchair edge model
(1D-3), (c) a zigzag edge model with lactol groups (1D-4), and (d) a zigzag model with inner
E-C-OH (1D-5). The part between two shadow areas is a unit cell along the ribbon direction.
The model shown in Figure 3a of the manuscript is labeled as 1D-1. Isolated epoxy group is
used to calibrate the core chemical shift.
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Figure S4. Models used to simulate line defect with an epoxy pair (2D-2). The model shown in
Figure 3b of the manuscript is labeled as 2D-1. Isolated epoxy group is used to calibrate the
core chemical shift.
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Table S3. Calculated R-CCS for C 1s in different environments.
carbon
relative core chemical shift (eV)
1D-3
1D-4
1D-5
2D-1
-1.9
-1.8 ~ -1.9
1D-1
1D-2
2D-2
clusters
C-H
-2.5
-1.8
2
C sp
-2.3 ~ -1.8 -1.6 ~ -1.7
-1.7
CH3
-1.6
-1.8
C-OH-edge
-0.6
-0.9
C=O
-0.5
-0.1*
-0.9
-0.7
C-MnO4
-0.7
C-E´
-0.6 ~ -0.4†
-0.4
-0.8~-0.4 -0.7~ -0.3 -0.7 ~ -0.4 -0.7 ~ -0.5
C-OH
+0.1 ~ +0.2 -0.1 ~ +0.1 +0.2 ~ +0.3 +0.1~+0.2
+0.3
+0.1
C-E
-0.1 ~ +0.2 -0.3 ~ +0.3 0.0 ~ +0.1
~0.0
~0.0
~0.0
~0.0
0.0
CP
-0.3~ -0.2
0.0 ~ +0.1
C-EP
+0.9 ~ +1.0
+0.9
+1.0
+1.0
+1.5
+1.1
COO(H)
+1.4
+1.2
+1.1
+0.9~+1.1
+1.3 ~ +1.9
C-OCOH
+1.5
+1.7
+1.9
+1.7 ~ +1.9
COOO
+3.0
* In 1D-2, an epoxy group and an OH group are connected to the neighboring carbon of the C=O edge group, which induces a high value of the
core chemical shift for this C=O carbon.
†
In 1D-2, carbon atoms connected to the COOO group are considered as C-E´.
5
1. H.-K. Jeong, Y. P. Lee, R. J. W. Lahaye, M.-H. Park, K. H. An, I. J. Kim, C.-W. Yang, C. Y. Park,
R. S. Ruoff, Y. H. Lee, J. Am. Chem. Soc. 2008, 130, 1363.
2. T. Szabo, O. Berkesi, P. Forgo, K. Josepovits, Y. Sanakis, D. Petridis, I. Dekany, Chem. Mater. 18,
2740 (2006).
3. V. Feyer, O. Plekan, R. Richter, M. Coreno, K. C. Prince, V. Carravetta, J. Phys. Chem. A, 112,
7806 (2006).
4. W. Zhang, V. Carravetta, O. Plekan, V. Feyer, R. Richter, M. Coreno and K. C. Prince, J. Chem.
Phys. 131, 035103 (2009).
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