Supplementary Information
Large-scale and Rapid Synthesis of Disk-Shaped and
Nano-Sized Graphene
Chunyong He†, San Ping Jiang*,‡, Pei Kang Shen*,†
†
State Key Laboratory of Optoelectronic Materials and Technologies, and Guangdong Province ey
Laboratory of Low-carbon Chemistry & Energy Conservation, School of Physics and Engineering,
Sun Yat-sen University, Guangzhou, 510275, PR China
‡
Fuels and Energy Technology Institute & Department of Chemical Engineering, Curtin
University, Perth, WA6102, Australia
* e-mail: stsspk@mail.sysu.edu.cn (P.K. Shen); s.jiang@curtin.edu.au (S.P. Jiang)
Synthesis of disk-shaped and nano-sized graphene (DSNG)
The ion-exchange resins are insoluble matrixes (or support structure) normally in the
form of small (1–2 mm diameter) beads, fabricated from an organic polymer substrate.
The highly developed pore structure of the ion-exchange resins on the surface
provides sites which can easily trap and release ions, simultaneously, the process is
called ion exchange. Based on the functional groups, resins are classified into four
basic categories: strong acid cation (SAC), weak acid cation (WAC), strong base
anion (SBA) and weak base anion (WBA). D113 resin belongs to weak acid cation
exchange resins, which derives its exchange activity from a carboxylic group
(-COOH). Scheme S1 is the typical profile of the ion exchange process. As illustrated
by the exchange reactions, D113 resin readily accepts cobalt ions by exchange
hydrogen ions during the ion exchange process. The exchanged ion then diffuses out
of the resin and back into the solution at opposite direction.S1
Scheme S1 The typical profile of the ion exchange process of D113 between Co2+
and H+.
The D113 resin (Shanghai Hualing Co. Ltd., China) was pre-treated before use by a
procedure as follows. The D113 resin was firstly washed with deionized water and
then soaked in a solution of mixed 1.0 mol L-1 NaClO and 1.0 mol L-1 HCl for 24 h in
order to remove impurities and to activate. The pre-treated resin was washed with
deionized water and dried at 80 oC. In a typical preparation process, 2.0 g CoCl2.6H2O
were dissolved in 200 ml deionized water and mixed with 20 g D113 resin (the mass
ratio of CoCl2 .6H2O to D113 resin: RCo/R = 0.1). After magnetic stirring for 2 h, the
metal ions exchanged D113 resin was rinsed with deionized water for several times
and dried in oven at 80 oC. After carbonization in tubular furnace at 400 oC under Ar
atmosphere condition for 2 h, the samples were heat treated at 1300 oC for 1 h. The
product was post-treated in 3.0 mol L−1 HCl solution for more than 12 h with
magnetic stirring to remove cobalt.
Effect of synthesis conditions on the morphology of DSNG
The effect of synthesis conditions such as the mass ratio of CoCl2.6H2O to D113 resin
on the morphology of graphene was investigated. In this experiment, 4.0 g, 8.0 g, 20 g
CoCl2.6H2O were dissolved in 200 ml deionized water and added 20 g D113 resin
(RCo/R = 0.2, 0.5 and 1), respectively. After treated by the same steps as mentioned
above, graphene samples with different morphologies were obtained.
Figure S1 shows the graphene sample synthesized by the same steps as mentioned
above but without carbonizing treatment in tubular furnace at 400 oC under Ar
atmosphere for 2 h. The morphology and structure of the graphene samples are highly
irregular with no formation of disk-shape graphene.
Figure S1. Tapping mode AFM image of the graphene-like sheets deposited on
new-delaminated mica at ambient conditions without carbonizing treatment in tubular
furnace at 400 oC under Ar atmosphere for 2 h.
Additional characterization and analysis results
Figure S2 shows the XRD pattern of the amorphous structure of the compound of
amorphous carbon(a-C) and cobalt after theD113resins located metal ions were
carbonized (pattern a). The pattern b shows clearly that graphitized carbon and
polycrystalline cobalt particles have been formed under the process of heating
condition. The diffraction peak at 26.2°, 42.2°, 44.4°, 54.0°, and 77.2° is the
characteristic of the graphite (002), (100), (101), (004) and (110) facets. The peaks at
the 2θ of 45.9°, 51.5°, 75.8°, 92.2° and 97.6°. Those peaks are corresponding to the
(111), (200), (220), (311), (222) facets of Co, showing the formation of
polycrystalline cobalt particles.S2 As shown in Figure S2 (pattern c), the diffraction
peaks of cobalt disappeared after post-treated by 3.0 M HCl for 12 h. This means that
the cobalt has been removed after the hydrochloric acid treatment.
Intensity / a. u.



c
 
Co
Graphite



b


a
10 20 30 40 50 60 70 80 90 100 110
2 theta
Figure S2. (a) The XRD pattern of the amorphous structure of the compound of
amorphous carbon(a-C) and cobalt after the D113 located metal ions were carbonized.
(b) The XRD pattern of Co/DSNG composite. (c) The XRD pattern of DSNG.
Figure S3 shows the Raman spectra of the graphene samples with different value of
RCo/R. All the Raman spectra of the graphene samples show the characteristics of
graphene.
G band
Negative shift 20cm
2D band
-1
D band
Intensity / a. u.
RCo/D113=0.2
RCo/D113=0.5
RCo/D113=1
HOPG
1000
1500
2000
2500
Raman shift / cm-1
3000
Figure S3. Raman spectra at 514 nm for the graphene samples with different RCo/R
and HOPG. The 2D band in the Raman spectrum obtained from graphene is formed by
one Lorentzian peak.
Figure S4 shows the high-resolution C1s XPS spectra of the graphene samples with
different value of RCo/R and HOPG. The C1s peak can be fitted by one Lorentzian
peaks at 284.6, corresponds to the graphite-like sp2 bonded carbon. The C1s spectrum
of graphene samples coincides with HOPG, indicating all the carbon atoms of
graphene samples are arranged in a conjugated honeycomb lattice.
Intensity / a.u.
C1s
294
RCo/R = 0.2
RCo/R = 0.5
RCo/R = 1
HOPG
292
290
288
286
284
282
280
Binding energy / eV
Figure S4. High-resolution C1s XPS spectra of the graphene samples with different
value of RCo/R and HOPG.
To further confirm the DSNG is formed in the process of heat treatment, instead of
in the process of acid treatment, we take AFM test for the Co/graphene composite
sample without acid treatment. In the case of the RCo/R equals 0.1, as seen from the
inhomogeneous height color of the AFM image in Figure S5a, there are obviously two
types of morphologies: the light yellow of the DSNG and the thick yellow in the inner
circle, which is certainly the cobalt particle on the top surface of the DSNG. When the
RCo/R increases to 0.2, we obtained well-shaped cobalt disks (Figure S5b). Increasing
the RCo/R to 0.5, we obtained DSNGs with different sizes of the cobalt particles
(Figure S5c), consequently, different sizes of the DSNGs. When the RCo/R reaches 1
(Figure S5d), the cobalt particles still located on the surface of the DSNGs, however,
the cobalt particles become irregular in shape and size and finally the DSNGs as well.
Figure S5. Tapping mode AFM images of Co/graphene (without acid treated)
deposited on on new-delaminated mica at ambient condition. (a) RCo/R = 0.1, (b) RCo/R
= 0.2, (c) RCo/R = 0.5, (d) RCo/R = 1.
Figure S6 shows the tapping mode AFM images of the Co/graphene (without acid
treatment) samples deposited on new-delaminated mica at ambient condition as a
function of mass ratio of CoCl2 .6H2O to D113 resin. The height profiles indicated that
the relative heights are 0.78 nm, 0.71 nm, 0.44 nm and 0.72 nm corresponding to the
different RCo/R.
Figure S6. Tapping mode AFM images of the Co/graphene (without acid treatment)
samples deposited on new-delaminated mica at ambient condition as a function of
mass ratio of CoCl2 .6H2O to D113 resin: (a) RCo/R = 0.1, (b) RCo/R = 0.2, (c) RCo/R =
0.5 and (d) RCo/R = 1. (a1-d1) are the height profiles along the blue lines in (a-c),
respectively. The folded edges of a-c exhibit relative heights of 0.78 nm, 0.71 nm,
0.44 nm and 0.72 nm, respectively.
Figure S7 Photograph of suspension of DSNG (1 mg ml−
N-methyl-2-pyrrolidone
1,2-Dichloroethane (EDC).
(NMP),
N,N-Dimethylformamide
1
) in H2O,
(DMF)
and
Normalized PL intensity
1.0
0.8
0.6
0.4
large flake
graphene
0.2
0.0
100
1000
10000
100000
Graphene size / nm
Figure S8 The relationship of the normalized PL intensity with the graphene size.
The origin of photoluminescence (PL) in these carbon-based nanomaterials is
tentatively proposed to be from isolated polyaromatic structures or passivated surface
defects.S15 For the PL mechanism of functionalized graphene, it is speculated that the
size effect, shape, fraction of the sp2 domains, and surface defects contribute to
PL.S12-14,S16 So the PL performance of functionalized graphene is decide by the size,
shape, defects, and preparation method. Table S1 displays different examples of the
photoluminescence from functionalized graphene. Details on fabrication method,
lateral size of the flakes, and PL performanc are included.
Table S1. The photoluminescent of functionalized graphene.
Size
Samples
nm
/
PL
Preparation method
Excited
emission wavelength References
peak
/ / nm
nm
GO
752
500
S3
570
400
S4
321
280
S5
440
325
S6
Modified Hummers 520
400
S4
321-421
280
S5
Reduce GO
390
325
S6
Micro-wave-assiste
303
197
S7
427
320
S8
430
320
S9
430
325
S10
Hummers method
20
Nano-GO
method
Reduced GO
3.4
d hydrothermal
5.3
Solvothermal
method
Graphene
quantum
(GQDs)
9.6
dots
Hydrothermal
approach
5-15
Hydrothermal
approach
15
Bottom–up method
460
365
S11
5-35
Ultrasound-assisted
300-470
325
S12
solvent method
60
Chemical
process 430-560
320-480
S13
plasma 700 nm
473
S14
270
Our work
from HBC
Oxygen plasma
Oxygen
treated
treatment
graphene
Disk-shaped
200
nanographene
Pyrolysis of D113 311
resin
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