Effects of tailoring and dehydrated cross-linking on morphology evolution of ordered mesoporous carbons

Article abstract of DOI:10.1039/c5ra26639d

In this study, using a template (Pluronic P123) as an in situ carbon source, ordered mesoporous carbons (OMC) were successfully synthesized through directing carbonization of templates. Two key factors in the morphology evolution of mesoporous carbon mate

Full text of DOI:10.1039/c5ra26639d

View Article Online
View Journal
RSC Advances
This article can be cited before page numbers have been issued, to do this please use: J. Zhang, D. Liu,
H. Song, Z. Liang, X. Guo, L. Du and S. Liao, RSC Adv., 2016, DOI: 10.1039/C5RA26639D.
This is an Accepted Manuscript, which has been through the
Royal Society of Chemistry peer review process and has been
accepted for publication.
Accepted Manuscripts are published online shortly after
acceptance, before technical editing, formatting and proof reading.
Using this free service, authors can make their results available
to the community, in citable form, before we publish the edited
article. This Accepted Manuscript will be replaced by the edited,
formatted and paginated article as soon as this is available.
You can find more information about Accepted Manuscripts in the
Information for Authors.
Please note that technical editing may introduce minor changes
to the text and/or graphics, which may alter content. The journal’s
standard Terms & Conditions and the Ethical guidelines still
apply. In no event shall the Royal Society of Chemistry be held
responsible for any errors or omissions in this Accepted Manuscript
or any consequences arising from the use of any information it
contains.
www.rsc.org/advances

Page 1 of 19
RSC Advances
View Article Online
DOI: 10.1039/C5RA26639D
Effects of tailoring and dehydrated cross-linking on morphology
evolution of ordered mesoporous carbons
1
Jiaxi Zhang , Dandan Liu , Huiyu song , Zhenxing Liang , Xuefeng Guo ,
1
1
1
2
1,
Li Du , Shijun Liao
1,†
1
Key Lab for Fuel Cell Technology of Guangdong Province & Key Lab of New Energy Technology
of Guangdong Universities, School of Chemistry and Chemical Engineering, South China
University of Technology, Guangzhou, 510641, China
2
The Sixth Affiliated Hospital of Sun Yat-sen University, Guangzhou, 510640, China
Abstract
In this work, by using template (Pluronic P123) as in situ carbon source, kinds of ordered
mesoporous carbons (OMC) were successfully synthesized through directing carbonization of
templates. Two key factors in the morphology evolution of mesoporous carbon materials were
introduced, one is the tailoring role of micelles by ethanediol, and the other is the dehydrated
cross-linking effect by sulfuric acid. Through the two factors, the morphology of as-synthesized
ordered mesoporous carbons can be altered from bulks to rods, even to sheets. Transmission
electron microscopy (TEM) showed ordered mesoporous carbon rods (OMCR) and ordered
mesoporous carbons sheets (OMCS) possessed regular morphology and good mesopore structure.
Nitrogen adsorption–desorption analysis confirmed that both OMCR and OMCS had high surface
2
−1
area and uniform mesopore distribution, OMCR had the highest surface area (919 m g ), and
OMCS owned the biggest pore size (9.11 nm). This study also showed that OMCR and OMCS
were good carbon carriers, the size of Pt loading nanoparticles can be decreased to 3 nm, and
especially Pt/OMCS presents very high Pt dispersion and uniform smallest Pt nanoparticles (2.49
nm).
Key words: ordered mesoporous carbons; mesopore structure; carbon materials
1. Introduction
Recently, the researchers have found that ordered mesoporous carbon (OMC) materials have
Corresponding author, Fax + 86 20 87113586, e-mail: duli@scut.edu.cn
†
Corresponding author, Fax + 86 20 87113586, e-mail: chsjliao@scut.edu.cn

RSC Advances
Page 2 of 19
View Article Online
DOI: 10.1039/C5RA26639D
great advantages in the field of fuel cell, lithium battery, hydrogen storage, adsorption, catalytic
1-8
reaction, electrochemistry and so on. Thus the designed synthesis of OMC materials with
controlled surface properties and structural ordering is important from a fundamental and
9
application point of view.
There are two typical methods for the synthesis of OMC, one is the nanocasting strategy from
mesoporous silica hard templates, and the other is the direct synthesis from block copolymer soft
templates. The typical representative of the two synthetic methods is as follows. For nanocasting
10
strategy, Ryoo et al. firstly reported an ordered mesoporous carbon, CMK-1, which was
fabricated by the preformed mesoporous silica MCM-48 served as a hard template, and then filled
the carbon precursor such as sucrose into the mesopore system of MCM-48 silica, followed by
pyrolysis, carbonization, and template removal to get CMK-1. For soft template method, Zhao’s
group reported an organic–organic self-assembly approach, by using this method, highly ordered
mesoporous carbons, denoted as FDU-15 and FDU-16, were synthesized through a solvent
evaporation induced self-assembly method (EISA) by using amphiphilic triblock copolymers
(PEO–PPO–PEO) as templates and a soluble low-molecular weight resol of phenol and
11
formaldehyde as the precursor.
Findings from the two approaches indicate that the OMC
material obtained from the soft template method is a positive phase structure, and the nanocasting
method leads to a relatively precise negative replica of the hard template. Compared with soft
template method, the syntheses of nanocasting method are easy to control the morphology and
mesopore structure of resultant OMC due to the fixed template structure.
However, by using mesoporous silica as a scaffold, it makes the process expensive,
complicated, and time-consuming, and consequently unsuitable for large-scale production and
9
industrial applications. Based on these disadvantages, some more cost-effective methods were
also invented by making use of as-synthesized mesoporous silica/surfactant mesophases as
12-16
starting materials, followed by the introduction of extra carbon precursors.
For example,
14
Moriguchi et al. reported a method for the synthesis of OMC materials with 2 nm wormhole-like
mesopores by in situ polymerization of divinylbenzene in the hydrophobic phase of hexagonally
15
arrayed micelle/silicated nanocomposite. Li et al. reported that by the post-treatment of the
as-synthesized P123/silica composite with sulfuric acid as a catalyst for cross-linking of P123, the
yield can be improved by employing sucrose as a supplementary carbon source. However, the

Page 3 of 19
RSC Advances
View Article Online
16
DOI: 10.1039/C5RA26639D
2
-1
surface area of OMC was only 610 m g and the pore size was also less than 3 nm. Lee et al.
also reported that uniform mesoporous carbons can be directly obtained from carbonization of
P123/phenol-resin/silica nanocomposites. However, the obtained OMC products exhibited
disordered and wormhole-like pore structure. Therefore, the synthesis conditions and
compositions still needed to be optimized in order to obtain OMC with ordered mesopore structure,
high surface area, large pore size, and special morphology.
In the present work, we report a low-cost, simple, convenient and green approach for the
synthesis of ordered mesoporous carbon materials from the SiO /P123/sucrose composite. By
2
investigating the effects of synthesis conditions and compositions, we found some interesting
results that the morphology, mesopore size of obtained OMC products can be altered by the
co-solvent and co-template addition, and the pre-treatment of sulfuric acid. The morphology of
as-synthesized ordered mesoporous carbons can be altered from bulks (OMCB) to rods (OMCR),
and even to sheets (OMCS). Meanwhile, the mesopore size can also be increased to 5.45 nm, and
even to 9.11 nm, respectively.
2. Experimental section
Preparation of materials
2.1 Preparation of SBA-15-DC-OMC
SBA-15 directly converted to ordered mesoporous carbons (SBA-15-DC-OMC) were gained
from SBA-15. The typical SBA-15 was prepared by using the tri-block copolymer, EO PO EO
20 70
20
17
(Pluronic P123, BASF) and tetraethyl orthosilicate (TEOS, 99%). In our previous synthesis of
18
SBA-15, 4.0 g of Pluronic P123 was dissolved in 126 mL of deionized (DI) water and 20 mL of
hydrochloric acid (37 wt%), and then 10 mL of TEOS was added and stirred for 20 h at 35 °C. The
slurry was hydrothermally treated at 100 °C for 24 h. Subsequently, the product was filtered, dried
and the white-colored powders were pyrolysed at 850 °C for 2 h in nitrogen (99.999%). Finally,
the silica template was removed in NaOH (10 M) at 120 °C for 4 h, followed by washing with DI
water, the final black-colored powders named SBA-15-DC-OMC.
2.2 Preparation of OMCB
Ordered mesoporous carbons bulks (OMCB) were prepared by using sucrose as

RSC Advances
Page 4 of 19
View Article Online
supplementary carbon source. In this synthesis, 4.0 of Pluronic P123 was dissolved in 1D6O0I:m10L.10o3f9/C5RA26639D
sulphuric acid (1 M), stirring to the time of the P123 dissolution. Then 10 mL of TEOS was added
and stirred for 20 h at 35 °C. The slurry was hydrothermally treated at 100 °C for 24 h.
Subsequently, the white SiO /P123 composites were filtered, dried at 100 °C for 6 h in air dry
2
oven. After drying, the colour of SiO /P123 powders become brown, followed by washing with DI
2
water to pH = 7. To encapsulate supplementary carbon into the channel gap, the brown-colored
powders were soaked in a crucible with a given solution for 30 min, the solution was composed of
3.0 g of sucrose and 10 mL of DI water, then the crucible was placed into air dry oven to firstly
remove water at 100 °C for 6 h and pre-carbonization at 160 °C for 6 h, then the products were
pyrolysed at 850 °C for 2 h in nitrogen (99.999%). After silica removal, the final powders named
OMCB.
2.3 Preparation of OMCR
Ordered mesoporous carbons rods (OMCR) were prepared by using ethanediol as co-solvent
and sucrose as supplementary carbon source. The different procedure is adding 30 mL of
ethanediol before TEOS addition, other process is same with synthesis of OMCB. After silica
removal, the final powders named OMCR.
2.4 Preparation of OMCS
Ordered mesoporous carbons sheets (OMCS) were prepared by using P123 and sucrose as
co-template and co-carbon source. In this synthesis, 4.0 of Pluronic P123 and 1.0 g sucrose were
dissolved in 126 mL of DI water and 20 mL of hydrochloric acid (37 wt%). After completely
dissolution, 30 mL of ethanediol was poured into the above solution and strried for 2 h at 35 °C,
and then 10 mL of TEOS was added and stirred for 20 h at 35 °C. The slurry was hydrothermally
treated at 100 °C for 24 h. Subsequently, the SiO /P123/sucrose composites were filtered, washed
2
and dried. For pre-carbonization process, 1.0 g of SiO /P123/sucrose mixture were dispersed in 10
2
mL of DI water and 1 mL of sulphuric acid (98 wt%) for 12 h at room temperature, then treated at
160 °C for 6 h. After pyrolysed at 850 °C for 2 h and silica removal, the final powders named
OMCS.
2.5 Loading Pt nanoparticles on OMC materials
Pt/OMC materials were prepared by an organic colloid method and the detailed preparation
19
method has been described in a previous paper. Briefly, hexachloroplatinate acid and sodium

Page 5 of 19
RSC Advances
View Article Online
citrate were dissolved in ethylene glycol (EG) to form a mixture and then stirred foDrO3I:010m.10in39./C5RA26639D
As-synthesized OMC was then added to the mixture under stirring. The pH of the solution was
adjusted to >10 by drop-wise addition of 5 wt% KOH in EG solution. The mixture was then
placed into a Teflon®-lined autoclave and conditioned at 120 °C for 6 h, followed by filtering,
washing and vacuum drying at 60 °C.
Characterization
Transmission electron microscopy (TEM) images were recorded on a JEM-2100 transmission
electron microscope (JEOL, Japan). X-ray diffraction (XRD) patterns were obtained using a
TD-3500 powder diffractometer (Tongda, China). Specific surface areas and pore size distribution
was determined using Brunauer–Emmett–Teller (BET) nitrogen adsorption–desorption on a
Tristar II 3020 (Micromeritics, USA) gas adsorption analyzer. Raman measurement was
performed on a LabRAM Aramis Raman spectrometer (HJY, France) with a laser wavelength of
632 nm.
Electrochemical testing
Electrochemical measurements were conducted in a standard three-electrode glass cell on an
electrochemical workstation (Ivium, Netherlands) at room temperature, coupled with a rotating
disk electrode (RDE) system (Pine Research Instrumentation, USA). A glassy carbon electrode
2
(GCE, with a diameter of 5 mm and an electrode area of 0.1964 cm ) was used as the working
electrode substrate, with an Ag/AgCl/KCl (3 M) electrode and a Pt wire as the reference electrode
and counter electrode, respectively. For simplicity, the Ag/AgCl/KCl (3 M) reference electrode is
hereafter abbreviated to Ag/AgCl. Before every measurement, the GCE surface was cleaned by
ultrasonication in ethanol and polished with an α-Al O slurry (50 nm) on a microcloth, followed
2
3
by rinsing with deionized (DI) water and drying under an infrared lamp.
A slurry of the active material was prepared by mixing 5.0 mg Pt/OMCS catalyst with 1 mL of an
ethanol solution containing Nafion (0.25 wt%) under ultrasonication. Next, 5 μL catalyst slurry
was pipetted onto the surface of the GCE, followed by drying under an infrared lamp to form a
−2
catalyst film on the GCE substrate. The catalyst Pt loading was approximately 25 μg Pt cm .
ORR measurements were carried out in O -saturated 0.1 M HClO electrolyte, using a rotation
2 4
–1
rate of 1600 rpm and a scan rate of 10 mVs . Before the ORR activity test, all the electrodes were
–1
pretreated by cycling the potential between 0 and 1.2 V at a sweep rate of 50 mVs for 20 cycles

RSC Advances
Page 6 of 19
View Article Online
DOI: 10.1039/C5RA26639D
to remove any surface contaminants. For comparison, a commercial Pt/C electrode (20 wt% Pt,
Johnson Matthey, UK) was also tested under the same conditions.
3. Results and discussion
3.1 Effect of sucrose addition on directing carbonization
Fig. 1 shows the TEM images of SBA-15 mesoporous silica and different mesoporous carbon
materials. As shown in Fig. 1A and 1B, the typical SBA-15 exhibits bulky morphology with very
ordered mesopore structure. When P123 template did not be removed, SBA-15-DC-OMC was
gained through directly carbonization of P123, the morphology still kept bulky without ordered
shape as shown in Fig. 1c. Unfortunately, a small quantity of SBA-15-DC-OMC can be collected
after silica removal, and also the ordered mesopore structure disappeared, the carbon materials
exhibited high degree of graphite with disordered mesopores as shown in Fig. 1D. We speculate
that the amount of P123 as a single in-situ carbon source is not sufficient for OMC formation, it
maybe due to the cold shrink of P123 molecules during filtering and washing caused the formation
of disordered mesopore structure. Thus it is crucial to fill another carbon source into the vacant
channels. Sucrose, an abundant and low-cost species, it is often utilized as a carbon source to
synthesize mesoporous carbon, when sucrose is used as supplementary carbon source, OMCB
materials exhibit better mesopore structure than SBA-15-DC-OMC, and the white pore stripes are
faintly visible as shown in Fig. 1F. It demonstrated that more regular pore structure of mesoporous
carbon materials could be received through adding supplementary carbon source.

Page 7 of 19
RSC Advances
View Article Online
DOI: 10.1039/C5RA26639D
A
C
E
B
D
200 nm
10 nm
F
200 nm
50 nm
Fig. 1 TEM images of (A-B) SBA-15 with bulky morphology; (C-D) SBA-15-DC-OMC; (E-F)
OMCB prepared by sucrose as supplementary carbon source.

RSC Advances
Page 8 of 19
View Article Online
DOI: 10.1039/C5RA26639D
3.2 Effect of tailoring of micelles by ethanediol
A
B
C
D
E
F
200 nm
200 nm
200 nm
50 nm
100 nm
20 nm
Fig. 2 TEM images of (A-C) SBA-15 with rod morphology; (D-F) OMCR.
Based on typical synthesis of SBA-15, we can successfully prepare mesoporous carbon
materials by using P123 as structure-directing agent and in situ carbon source, but the shape of
synthesized particles is large and bulky. In order to solve this problem, we tried to use ethanediol
as co-solvent to tailor the micelles of P123. From Fig. 2A, it can be obviously seen that the
particles of SBA-15 mesoporous silica become rods from bulks through using ethanediol as a
co-solvent, meanwhile it also can be clearly observed ordered mesopore structure taken in the (110)

Page 9 of 19
RSC Advances
View Article Online
direction in Fig. 2B and 2C. Compared with SBA-15 rods, the morphology of OMCB isDbOaI:s1i0c.a10ll3y9/C5RA26639D
copied from SBA-15 rods precursor as shown in Fig. 2D. Remarkably, the mesopore channel
seems to be piled up by massive carbon nanowires as shown in Fig. 2E and 2F. It shows
well-ordered hexagonal arrays of carbon nanorods and further confirms that the OMCR sample
20
has a 2D hexagonal (p6mm) meso-structure. Hence, we can see that the tailor effect of
ethanediol is very crucial to the formation of OMCR materials. The possible formation process of
OMCR is shown in Scheme 1. First, the molecules of P123 are self assembly in acidic solution,
and then regular ordered micelles with rod-like structure are assembled by adding ethanediol as
co-solvent. After hydrothermal treatment, the white SiO /P123 composites should be filtered,
2
dried. In the process of drying, the sulfuric acid in original solution gradually becomes
concentrated sulfuric acid, which makes the P123 further dehydrated cross-linking. The white
gaps are formed around P123 molecules after dehydrated cross-linking, so supplementary carbon
of sucrose will be introduced to fill with the white gaps. Afterwards, SiO /P123/sucrose
2
composites are pyrolysed at 850 °C for carbonization. Finally, ordered mesoporous carbon rods
can be received after silica removal.
tailoring
self assembly
of micelles
PEO
by ethanediol
PPO
dehydrated
sucrose
cross-linking
addition
by H SO
P123
2
4
sucrose
SiO /P123/sucrose
2
SiO
2
SiO /P123
2
SiO /P123-H O
2 2
pyrolysed
at 850 °C
removal
of SiO
2
ordered mesoporous carbon rods
Scheme 1 Schematic diagram of OMCR formation process.
SiO /C
2

RSC Advances
Page 10 of 19
View Article Online
DOI: 10.1039/C5RA26639D
3.3 Effect of dehydrated cross-linking by sulphuric acid
A
B
200 nm
100 nm
C
D
50 nm
200 nm
Fig. 3 TEM images of OMCS.
A
B
200 nm
100 nm
Fig. 4 TEM images of OMC without pretreatment by sulfuric acid.
From the above TEM results of OMCB and OMCR, we found that ordered mesoporous
carbon materials with uniform mesopore structure could be prepared through using P123 as a

Page 11 of 19
RSC Advances
View Article Online
single template and using sucrose as supplementary carbon source. However, whether suDcOroI:s1e0.1c0a3n9/C5RA26639D
be added in advance, and whether sucrose can be used as co-template and co-carbon source with
P123 together? In order to explore this problem, we carried out experiments with P123 and
sucrose as co-template. To avoid the dehydration of sucrose in concentrated sulfuric acid
environment, we used HCl as the acid medium, ethanediol as co-solvent, and the
SiO /P123/sucrose composites were obtained by hydrothermal crystallization. In the next process
2
of sulfuric acid treatment, we found a very interesting phenomenon, when the composites were
soaked into the concentrated sulfuric acid for dehydrated cross-linking of the carbon sources, if
not washed, the brown filtered sample was directly placed in the drying oven at 160 °C for
pre-carbonization, the structure of resultant sample (OMCS) was shown in Fig. 3. The OMCS
exhibits a thin sheet structure, and the ordered mesopore structure in the (110) direction can be
clearly seen in the sheet as shown in Fig. 3B. If washed completely, the product exhibits a long
rod with large defect structure, but not a sheet as shown in Fig. 4. Results show that, the presence
of sulfuric acid is very important to the formation of sheets carbon materials. The possible
formation process is shown in Scheme 2. When P123 and sucrose are used as co-template, the
composites of SiO /P123/sucrose are formed after the hydrolysis of TEOS. During the
2
pretreatment of concentrated sulfuric acid, dehydrated cross-linking and pre-carbonization will
happen between the molecules of P123 and sucrose, which results in the formation of hollow
carbon tube within the area of white dots. Lastly through NaOH etching, the hollow carbon tube
breaks off with the removal of SiO , then lots of ordered mesoporous carbon sheets will be formed
2
as shown in Scheme 2.
P123
dehydrated
cross-linking,
SiO
2
pre-carbonization
sucrose
by H SO
2
4
SiO /P123/sucrose
2
SiO /C
2
breaking off
removal
of SiO
2
hollow carbon tube
ordered mesoporous carbon sheets
Scheme 2 The possible formation process of OMCS.

RSC Advances
Page 12 of 19
View Article Online
DOI: 10.1039/C5RA26639D
3.4 Physical properties of OMC
150
1000
0.2
0.1
0.0
A
B
120
750
500
250
90
0.15
0
4
8
1216
50
100
Pore Diameter (nm)
0.10
0.05
0.00
60
30
0
0
2
4
6
8
50
100
Pore Diameter (nm)
0
0.0
0.2
0.4
0.6
0.8
1.0
0.0
0.2
0.4
0.6
0.8
1.0
Relative pressure (P/P )
0
Relative pressure ( P/P )
0
500
400
300
200
100
0
1400
1200
1000
800
600
400
200
0
0.3
C
D
0.2
0.1
0.0
0.2
0.1
0.0
0
2
4
6
8
50
100
0
4
8
1216
50
100
Pore Diameter (nm)
Pore Diameter (nm)
0.0
0.2
0.4
0.6
0.8
1.0
0.0
0.2
0.4
0.6
0.8
1.0
Relative pressure ( P/P )
0
Relative pressure ( P/P )
0
Fig. 5 Nitrogen adsorption–desorption isotherms (inset: pore size distribution of corresponding
samples): A) SBA-15-DC-OMC; B) OMCB; C) OMCR; D) OMCS.
Table 1 Calculated porosity parameters of all samples
Samples
S
/
V
/
BJH
Pore size/
nm
BET
2
-1
3
-1
m ·g
cm ·g
21
SBA-15
647
318
710
919
442
0.87
0.19
1.14
1.15
0.56
7.90
2.69
4.37
5.45
9.11
SBA-15-DC-OMC
OMCB
OMCR
OMCS
Fig. 5 presents the nitrogen adsorption–desorption isotherms and pore size distribution (by
BJH method, inset figure) of different mesoporous carbon materials. OMCR exhibits the highest
2
−1
2
−1
2
−1
surface area of 919 m g , followed by OMCB (710 m g ), OMCS (442 m g ), and lowest
2
−1
surface area of SBA-15-DC-OMC (318 m g ) (Table 1). The total pore volume of OMCR (1.15

Page 13 of 19
RSC Advances
View Article Online
3
-1
3
-1
DOI: 10.1039/C5RA26639D
cm g ) is larger than that of OMCS (0.56 cm g ), this may be due to OMCR possesses more
pore structure than two-dimensional structure of OMCS. However, the mean pore size of OMCS
(9.11 nm) is bigger than that of OMCR (5.45 nm), and this result is also consistent with the results
of previous TEM analysis. Besides, we found that OMCS has a multi-level pore channel, mainly
concentrated in 5 nm and 14 nm as shown in Fig. 5D. It may be attributed to the dehydrated or
peeled effect of carbon materials with the presence of concentrated sulfuric acid.
The low angle range XRD patterns of all synthesized mesoporous carbon materials are shown
in Fig. 6A. It is observed that the as-synthesized OMCR exhibited three peaks, which can be
17
assigned to diffraction from the (100), (110), and (200) planes of SBA-15, indicating the
presence of a long-range ordered structure. However, we only can see a very weak diffraction
peak corresponding to the (110) plane of OMCS, we guess that may be due to the relative
disordered structure in two-dimensional of OMCS, and this result is also consistent with the
observation in previous TEM analysis . The high angle patterns of all samples are presented in Fig.
6B. At 23.6 °C and 43.5 °C, two typical diffraction peaks are detected, these peaks are assigned to
C (002) and C (101), respectively.
(100)
A)
B)
a) OMCB
b) OMCR
c) OMCS
a) OMCB
b) OMCR
c) OMCS
(002)
(101)
a
a
(110)
(200)
b
b
c
c
1
2
3
4
5
6
7
8
9 10
10 20 30 40 50 60 70
2θ (degree)
2θ (degree)
Fig. 6 XRD patterns of all synthesized mesoporous carbon materials. A) low angle diffractions; B)
high angle diffractions.

RSC Advances
Page 14 of 19
View Article Online
200
150
100
50
1315
DOI: 10.1039/C5RA26639D
1588
I /I = 1.16
D G
OMCB
0
200 800 1000 1200 1400 1600 1800 2000
150
100
50
I /I = 1.42
D G
OMCR
0
800 1000 1200 1400 1600 1800 2000
200
150
100
50
I /I = 1.27
D G
OMCS
0
800 1000 1200 1400 1600 1800 2000
-1
cm
Raman shift
(
)
Fig. 7 Raman spectra of different samples.
−1
Fig. 7 shows the Raman spectra of different samples. Peaks at ~1315 and ~1588 cm are
assigned to the D and G bands of carbon, respectively. Generally, The G band arises from the bond
2
3
stretching of sp bonded pairs, including C–C, while the D band is corresponding to the sp defect
sites, including vacancy and hetero atoms. Therefore, the ratio of the D and G band intensities
(I /I ) is commonly considered as an indicator of the extent of defects in carbon materials. As
D
G
shown in Fig. 7, the peak intensity ratios of the D to G bands (I /I ) are 1.16, 1.42, and 1.27 for
D G
OMCB, OMCR, and OMCS, respectively. Although there is no significant change in the
position of D and G bands, OMCS shows a lower I /I value than that of OMCR (1.27 vs. 1.42),
D G
possibly caused by two-dimensional structure of OMCS.
3.5 Investigation of Pt loaded on OMC materials
As we known, porosity is highly desirable to achieve excellent catalytic performance because
22
it facilitates high mass transfer fluxes and active loading. Therefore, porous carbon nanoparticles
are suitable for catalyst preparation. We carried out some trials to investigate whether the
morphology or mesopore structure of ordered mesoporous carbons will influence metal
nanoparticles loading. When we used our synthesized mesoporous carbons as carbon carrier and
Pt as loading metal, the high dispersion Pt loaded samples were prepared. The results show in Fig.
8, Pt/OMCB exhibits a little bit aggregation (Fig. 8B) and the particle size of Pt centered at 6.21

Page 15 of 19
RSC Advances
View Article Online
DOI: 10.1039/C5RA26639D
nm (Fig. 8C). Compared with Pt/OMCB, Pt/OMCR shows better Pt dispersion (Fig. 8E), and its
particle size centered at 2.94 nm (Fig. 8F). Satisfyingly, Pt/OMCS presents very high dispersion
on carbon sheets, and uniform Pt nanoparticles decreased to 2.48 nm (Fig. 8G). It can be seen that
the morphology of the carbon carrier has an important influence on the metal loading, and the high
ductility of the two-dimensional sheet structures can be seen as an ideal carrier material.
35
A
D
H
B
E
I
Mean=6.21nm
C
30
25
20
15
10
5
0
5.0
5.5
6.0
6.5
7.0
7.5
200 nm
200 nm
200 nm
20 nm
50 nm
20 nm
Particle size (nm)
40
35
30
25
20
15
10
5
Mean=2.94 nm
F
0
1.5 2.0 2.5 3.0 3.5 4.0 4.5 5.0
Particle size (nm)
50
Mean=2.48 nm
G
40
30
20
10
0
1.5
2.0
2.5
3.0
3.5
4.0
Particle size (nm)
Fig. 8 TEM images of mesoporous carbon materials loaded with 20 wt% Pt and their
corresponding particle size of distribution. A-C) Pt/OMCB; D-F) Pt/OMCR; H-G) Pt/OMCS.

RSC Advances
Page 16 of 19
View Article Online
DOI: 10.1039/C5RA26639D
0.6
0.4
0.2
0.0
20% Pt/C
20% Pt/OMCS
0
-3
-6
-1
Mass activity (Amg )
20% Pt/C
In O -saturated 0.1 M HClO
2
4
20% Pt/OMCS
1600rpm
0.0
0.2
0.4
0.6
0.8
Potential / V vs. Ag/AgCl
Fig. 9 ORR performances of 20% Pt/OMCS and JM 20% Pt/C catalysts and their mass activity
(inset figure).
To investigate the catalytic performance of Pt loaded on OMC materials, we took a
preliminary study on ORR electrochemical activity. We compared our best Pt dispersion sample,
20% Pt/OMCS catalyst, with commercial Pt/C using almost the same Pt loading. Figure 9 shows
the polarization curves of JM 20% Pt/C and 20% Pt/OMCS in O -saturated 0.1 M HClO solution,
2
4
–1
using a rotating disk electrode (RDE) at 1600 rpm and a scan rate of 10 mVs , with the current
density normalized to the geometric surface area of the electrodes. As shown in Figure 9, 20%
Pt/OMCS catalyst exhibited higher ORR catalytic activities than JM 20% Pt/C. With almost the
same Pt loading, the half-wave potential of 20% Pt/OMCS catalyst surpassed 20 mV higher than
that of the Pt/C catalyst, and the mass activity of 20% Pt/OMCS catalyst is almost 1.5 times higher
than that of JM 20% Pt/C. Hence, it demonstrated that our prepared Pt loaded catalyst has reached
the level of commercial Pt/C catalyst, but it also need to optimize the catalyst in the detailed
investigation in our next work.

Page 17 of 19
RSC Advances
View Article Online
DOI: 10.1039/C5RA26639D
4. Conclusions
In summary, two kinds of ordered mesoporous carbons with regular structure (rods and sheets)
were synthesized through a facile direct carbonization of templates. By using P123 as template,
sucrose as supplementary carbon source or co-template, ethanediol as tailoring agent and
sulphuric acid as dehydrated cross-linking agent, OMCR and OMCS were successfully
synthesized, respectively. Both of them possess high surface area and uniform mesopore
2
-1
structure, the surface area of OMCR is high up to 919 m g , meanwhile OMCS also possesses
high surface area relative to the similar layer structure of mesoporous carbon materials. It has
confirmed that both OMCR and OMCS are good carbon carriers, the size of loading Pt
nanoparticles can be decreased to 3 nm, especially Pt/OMCS presents very high Pt dispersion and
uniform smallest Pt nanoparticles. Hence, it can be seen that OMCR and OMCS will be as a
potential candidate for carbon carriers to fabricate noble metal or non noble metal electrochemical
catalyst. More detailed work in catalysis application will be reported by our group in the near
future.
Acknowledgements
This work was supported by the National Natural Science Foundation of China (NSFC Project no.
51302091, 51102099, 11132004), Science and Technology Planning Project of Guangdong
Province, China (2013B022000035), and the Fundamental Research Funds for the Central
Universities, SCUT.
References
1
2
L. Li, H. Song and X. Chen, Electrochim. Acta, 2006, 51, 5715–5720.
W. Ding, L. Li, K. Xiong, Y. Wang, W. Li, Y. Nie, S. G. Chen, X. Q. Qi and Z. D. Wei. J. Am.
Soc. Chem., 2015, 137, 5414–5420.
3
J. Galo, A.A. de, G.J. Soler-Illia, C. Sanchez, B. Lebeau, J. Patarin, Chem. Rev., 2002, 102,
4093–4138.
4
A. Taguchi and F. Schüth, Micropor. Mesopor. Mater., 2005, 77, 1–45.

RSC Advances
Page 18 of 19
View Article Online
Z. Guo, G. Zhu, B. Gao, D. Zhang, G. Tian, Y. Chen, Carbon, 2005, 43, 2344–2351.DOI: 10.1039/C5RA26639D
5
6
7
J. Lee, J. Kim and T. Hyeon, Adv. Mater., 2006, 18, 2073–2094.
C. H. You, S. J. Liao, X. C. Qiao, X. Y. Zeng, F. F. Liu, R. P. Rui, H. Y. Song, J. H. Zeng and
Y. W. Li, J. Mater. Chem. A, 2014, 2, 12240–12246.
8
9
A.H. Lu and F. Schüth, Adv. Mater., 2006, 18, 1793–1805.
T. Y. Ma, L. Liu and Z. Y. Yuan, Chem. Soc. Rev., 2013, 42, 3977–4003.
10 R. Ryoo, S.H. Joo and S.J. Jun, J. Phys. Chem. B, 1999, 103, 7743–7746.
11 Y. Meng, D. Gu, F. Zhang, Y. Shi, H. Yang, Z. Li, C. Yu, B. Tu and D. Zhao, Angew. Chem.
Int. Ed., 2005, 44, 7053–7509.
12 S. B. Yoon, J. Y. Kim and J. Yu, Chem. Commun., 2002, 14, 1536–1537.
13 J. Pang, V. T. John, D. A. Loy, Z. Yang and Y. Lu, Adv. Mater., 2005, 17, 704–707.
14 I. Moriguchi, Y. Koga, R. Matsukura, Y. Teraoka, Y.M. Kodama, Chem. Commun., 2002, 17,
1844–1845.
15 L. Li, H. Song and X. Chen, Micropor. Mesopor. Mater., 2006, 94, 9–14.
16 J. Lee, J. Kim, S. Yoon, S.M. Oh and Y. Hyeon, Chem. Mater., 2004, 16, 3323–3330.
17 D. Y. Zhao, J. L. Feng, Q. S. Huo, N. Melosh, G. H. Fredrickson, B. F. Chmelka and G. D.
Stucky, Science, 1998, 279, 548–552.
18 K. Wan, G. F. Long, M. Y. Liu, L. Du, Z. X. Liang and P. Tsiakaras, Appl. Catal. B-Environ.,
2015, 165, 566–571.
19 Y. N. Wu, S. J. Liao, Z. X. Liang, L. J. Yang and R. F. Wang, J. Power Sources, 2009, 194,
805–810.
20 C. C. Ting, H. T. Wu, S. Vetrivel, D. Saikia, Y. C. Pan, G. T. K. Fey and H. M. Kao, Micropor.
Mesopor. Mater., 2010, 128, 1–11.
21 J. X. Zhang, G. W. Huang, C. Zhang, Q. H. He, C. Huang, X. Yang, H. Y. Song, Z. X. Liang,
L. Du and S. J. Liao, Chin. J. Catal., 2013, 34, 1519–1526.
22 R. Wang, T. Zhou, H. Li, H. Wang, H. Feng, J. Goh and S. Ji, J. Power Sources, 2014, 261,
238–244.

Page 19 of 19
RSC Advances
View Article Online
DOI: 10.1039/C5RA26639D
Graphical Abstract
tailoring
of micelles
by ethanediol
OMCR
200 nm
dehydrated
cross-linking,
pre-carbonization
by H2SO4
OMCS
200 nm
Self template in situ construction of OMC was investigated through the tailoring of micelles and
dehydrated cross-linking effects.
1