- Email: [email protected]
Synthesis of monodisperse carbonaceous beads with ordered mesoporous structure
CARBON
4 7 ( 2 0 0 9 ) 9 2 9 –9 3 2
available at www.sciencedirect.com
journal homepage: www.elsevier.com/locate/carbon
Synthesis of monodisperse carbonaceous beads with ordered mesoporous structure Jintawat Chaichanawong, Takuji Yamamoto*, Sho Kataoka, Akira Endo, Takao Ohmori Research Institute for Innovation in Sustainable Chemistry, National Institute of Advanced Industrial Science and Technology (AIST), 1-1-1 Higashi, Tsukuba, Ibaraki 305-8565, Japan
A R T I C L E I N F O
A B S T R A C T
Article history:
Ordered mesoporous carbonaceous (OMC) beads were synthesized by a combination of the
Received 11 July 2008
syringe injection (SI) method and the evaporation-induced self-assembly (EISA) method. In
Accepted 15 November 2008
the SI method, a phenol-formaldehyde (PF) resin solution used as a carbon source is
Available online 27 November 2008
injected into an oil phase, in which the PF resin solution is insoluble, by carefully controlling the viscosity of the PF resin solution. Ordered mesoporous structure was formed based on the EISA method by adjusting the temperature for polymerization of the PF resin. Consequently, monodisperse OMC beads were obtained. Ó 2008 Elsevier Ltd. All rights reserved.
Ordered mesoporous materials are of particular interest due to their unique porous structure, which features periodic pore symmetry, large pore volume, high specific surface area, controllable mesopore distribution, and uniform pore size. These properties are potentially advantageous in many applications such as adsorption, gas separation, catalysis, water and air purification, hydrogen storage, column packing materials for high performance liquid chromatography (HPLC) and in electrical double layer capacitors [1–7]. Ordered mesoporous carbon materials have been synthesized by multi-step procedures using, for example, ordered mesoporous silica or zeolite as a hard template [8,9]. Ordered mesoporous carbon structures have recently been newly synthesized using a solvent evaporation-induced self-assembly (EISA) method that employs amphiphilic triblock copolymer (PEO-PPO-PEO) as a soft template, and phenol-formaldehyde resin as a carbon precursor [10,11]. This method avoids the use of a hard template and reduces the number of preparation steps. In various chemical processes for energy production or environmental protection, catalysts or adsorbents are often packed in a fixed-bed reactor or a column [12]. Monodisperse carbon beads are favored as packing materials for fixed-bed or fluidized-bed reactors, since they have better mechanical
strength and facilitate process design. It is therefore very important to establish a method of producing carbon beads of uniform particle size. Yamamoto et al. [13] have successfully prepared monodisperse carbon beads with developed mesoporosity using a novel method. They refer to their method as the ‘‘syringe injection (SI) method’’. The key process for obtaining monodisperse carbon beads is the controlled formation of droplets of a resorcinol-formaldehyde aqueous solution, used as a carbon precursor source, in an oil phase, in which water is insoluble, using an injection apparatus. By changing the circulation flow rate of the continuous phase, it has proved possible to control the size of the carbon beads. To the best of our knowledge, synthesis of monodisperse carbon beads with ordered mesoporous structure has not yet been reported. In the present study, a combination of the SI method [13] and the EISA method (the synthesis procedure is shown in the Supplementary information) was examined with the aim of producing monodisperse carbon beads with an ordered mesoporous structure. First, resol resin was prepared as a carbon source from phenol and formaldehyde in the manner of Meng et al. [10]. Sodium hydroxide was used as the catalyst. Then, amphiphilic triblock copolymer Pluronic F127 (BASF Japan Ltd.), dissolved
* Corresponding author: Fax: +81 29 861 4660. E-mail address: [email protected] (T. Yamamoto). 0008-6223/$ - see front matter Ó 2008 Elsevier Ltd. All rights reserved. doi:10.1016/j.carbon.2008.11.029
930
CARBON
4 7 ( 2 0 0 9 ) 9 2 9 –9 3 2
in ethanol, was mixed with the prepared resol resin. The molar ratio of phenol: formaldehyde: sodium hydroxide: F127 was fixed at 1: 2: 0.1: 0.012. After a homogeneous phenolformaldehyde (PF) resin solution was obtained, ethanol was evaporated to different extents to produce solutions with a range of viscosities. The viscosity of each solution was measured at 25 °C using an Ostwald viscometer. Beads were then synthesized from the solutions using the SI method [13]. In the SI method, the PF resin solutions are injected into silicone oil at constant speed via a syringe pump. Lengths of emerging PF resin solution were ‘snipped off’ at fixed time intervals by the pulsed flow of the silicone oil, which was circulated in a Teflon tube, creating monodisperse droplets. The droplets were kept in an oil bath at different temperatures to induce thermopolymerization (the formation of a rigid framework which can be transformed into an ordered structure by subsequent pyrolysis). The temperature of thermopolymerization was varied from 90 to 120 °C to vary the size and porous properties of the beads. The obtained beads were washed three times in cyclohexane and dried at room temperature. The
beads were then pyrolyzed in an argon gas flow at 350 °C for 3 h to obtain ordered mesoporous carbonaceous (OMC) beads. The OMC beads synthesized at 90 °C were labeled OMC-90. The OMC beads were observed using an optical microscope and the particle size distributions were determined by analyzing images of the beads. The uniformity of the beads was evaluated based on the coefficient of variation (CV), obtained by dividing the standard deviation of the particle size distribution by the mean diameter. The porous structure of OMC beads was observed using a transmission electron microscope (HF-2000 TEM, Hitachi Ltd.). The porous properties of the OMC beads were determined from the adsorption and desorption isotherms of nitrogen measured at 196 °C. In this article, the IUPAC definitions of a mesopore (dp = 2– 50 nm; dp denotes pore diameter) and a micropore (dp < 2 nm) are applied. Fig. 1a shows an image of OMC beads. The inset shows the particle size distributions (PSD) of OMC beads which were prepared after evaporating 70 or 80 wt.% of ethanol, respectively. It is noteworthy that the OMC beads have a spherical shape. The mean diameter of the beads prepared after removing 80 wt.% of ethanol was approximately 0.3 mm. Under
a a
600
OMC-90 OMC-100 OMC-110 OMC-120
Distribution [%]
70 wt.% 80 wt.%
40
400 300
3
50
q [cm (STP)/g]
500
30
200
20 10 0
100 0
0.2 0.4 0.6 Diameter [mm]
0 0
b
0.2
0.4
0.6
0.8
1
p/p0 [-] 50
b
4.0
dVp/dlog(dp) [cm /g·nm]
30
OMC-90 OMC-100 OMC-110 OMC-120
3.0
3
Viscosity [Pa·s]
40
20
10
0 0
20
40
60
80
100
Ratio of evaporated ethanol [wt.%] Fig. 1 – (a) Image of OMC beads. The inset shows the particle size distribution of OMC beads. (b) Relation between the amount of evaporated ethanol and the viscosity of PF resin solution.
2.0
1.0
0 1
10
100
dp [nm] Fig. 2 – (a) Adsorption and desorption isotherms of nitrogen on OMC beads. Closed symbols: adsorption; open symbols: desorption. (b) Pore size distributions of OMC beads.
CARBON
931
4 7 (2 0 0 9) 9 2 9–93 2
these conditions, the viscosity of the PF resin solution makes it suitable for injection. Since the corresponding CV was less than 20%, monodisperse beads were obtained. Based on our observations, uniform droplets are easily obtained only when the frequency of formation of the droplets, which detach from the tip of the needle, is synchronized with the frequency of the pulsed flow of silicone oil in the Teflon tube. If more than 80% of the ethanol was evaporated, the viscosity of the PF resin solution becomes too high to inject, as shown in Fig. 1b. In contrast, if the amount of evaporated ethanol was less than 80%, spherical beads could not be formed. A broader PSD was obtained with a CV value larger than 30%. Judging from these results, we regard the amount of ethanol in the PF resin solution as being the most important factor in controlling the particle size of the OMC beads. Fig. 2 shows adsorption and desorption isotherms of nitrogen on OMC beads and corresponding pore size distributions. They exhibit a typical type-IV isotherm with hysteresis loops and a capillary condensation step at a relative pressure about 0.4–0.8, characteristics typical of mesoporous materials. The porous properties of OMC beads were determined by applying the as-plot to the adsorption isotherm of nitrogen [14] and are summarized in Table 1. It should be noted that the porous structure of OMC-90 and OMC-100 are mainly composed of mesopores. On the other hand, some micropores are formed in OMC-110 and OMC-120. As shown in Fig. 2b, it is confirmed that the OMC beads possess a narrow pore size distribution in the mesopore range (dp 4–7 nm). OMC-110 and OMC-120 show larger pore sizes than OMC-90 and OMC-100. This
indicates that the different curing temperature affected the hydrocarbon framework structure resulting from thermopolymerization. Fig. 3 shows TEM images of OMC-90, viewed from the [1 1 1] and [1 1 0] directions. The inset shows the corresponding X-ray diffraction pattern, which confirms the formation of an ordered hexagonal mesoporous structure. The pore size of OMC-90 is approximately 5 nm, which is consistent with that determined by the nitrogen adsorption method. Based on our observations, OMC-90 possesses an ordered mesoporous structure throughout the entire bead. XRD patterns of OMC beads are shown in Fig. 4. In OMC-90 and OMC-100, an intense diffraction peak and two weak peaks were observed in a 2h range of 0.5–2.0, which confirm the existence of hexagonal structure. In addition, the XRD patterns of OMC-90 and OMC-100 show a better-resolved peak than those of OMC-110 and OMC-120. This observation indicated the high degree of ordered hexagonal structure, and also confirms that the formation of a hydrocarbon framework structure is closely dependent on the thermopolymerization temperature. At relatively high temperature (>100 °C), mesoporous structure would be deformed due to the faster polymerization rate of PF resin. In conclusion, ordered mesoporous carbonaceous (OMC) materials were synthesized in the form of beads by combining the SI method with the EISA method. The results of this study show that it is possible to prepare monodisperse OMC beads by carefully adjusting both the amount of ethanol contained in the PF resin solution used as a carbon source and the temperature used for thermopolymerization.
Table 1 – Porous properties of the prepared OMC beads. Sample
OMC-90 OMC-100 OMC-110 OMC-120
aBETa
atotalb
aextb
Vtotalb
Mesopore
2
[m /g]
2
[m /g]
2
[m /g]
[cm3/g]
amesb [m2/g]
340 394 517 513
345 387 514 518
40 49 68 47
0.37 0.38 0.60 0.57
305 338 327 352
ames/aBET [ ] 0.90 0.86 0.63 0.69
Micropore
Vmesb [cm3/g]
dpeakc [nm]
amicb [m2/g]
amic/aBET [ ]
Vmicb [cm3/g]
0.37 0.38 0.53 0.50
3.8 3.8 7.1 6.2
– – 119 119
– – 0.23 0.23
– – 0.07 0.07
a BET surface area. b Determined by using as-plot: total surface area (atotal), external surface area (aext), mesoporous surface area (ames), microporous surface area (amic), total pore volume (Vtotal), mesopore volume (Vmes) and micropore volume (Vmic). c The peak diameter of mesopores.
Fig. 3 – TEM image of OMC-90. (a) [111] direction, (b) [110] direction.
932
a
CARBON
4 7 ( 2 0 0 9 ) 9 2 9 –9 3 2
b
10
OMC-120
OMC-110
10
Intensity (a.u.)
Intensity (a.u.)
(×5 magnifications) 10
OMC-120 20 20
10
OMC-100
OMC-110 21 21
OMC-90 1
2
3
2θ (degree)
4
5
1.0
1.5
2.0
OMC-100 OMC-90 2.5
3.0
2θ (degree)
Fig. 4 – XRD patterns of OMC beads.
Acknowledgement The authors are grateful to the financial support from New Energy and Industrial Technology Development Organization (NEDO).
Appendix A. Supplementary data Supplementary data associated with this article can be found, in the online version, at doi:10.1016/j.carbon.2008.11.029.
R E F E R E N C E S
[1] Liu X, Zhou L, Li J, Sun Y, Su W, Zhou Y. Methane sorption on ordered mesoporous carbon in the present of water. Carbon 2006;44(8):1386–92.
[2] Yuan X, Zhuo SP, Wei X, Cui HY, Dai XD, Lui XM, et al. Aqueous dye adsorption on ordered mesoporous carbon. J Colloid Interface Sci 2007;310(1):83–9. [3] Wang H, Wang A, Wang X, Zhang T. One-pot synthesized MoC imbedded in ordered mesoporous carbon as a catalyst for N2H4 decomposition. Chem Commun 2008;22:2565–7. [4] Kim W, Kim P, Joo JB, Shin HK, Jung KS, Yi J. The preparation and characterization of porous carbons for hydrogen storage. J Electroceram 2006;17(2–4):679–82. [5] Armandi M, Bonelli B, Bottero I, Area´n CO, Garrone E. Synthesis and characterization of ordered porous carbons with potential applications as hydrogen storage media. Microporous Mesoporous Mater 2007;103(1–3):150–7. [6] Yuan ZY, Su BL. Insights into hierarchically mesomacroporous structured materials. J Mater Chem 2006;16:663–77. [7] Xing W, Qiao SZ, Ding RG, Li F, Lu GQ, Yan ZF, et al. Superior electric double layer capacitors using ordered mesoporous carbons. Carbon 2006;44(2):216–24. [8] Ryoo R, Joo SH, Kruk M, Jaroniec M. Ordered mesoporous carbons. Adv Mater 2001;13(9):677–81. [9] Kyotani T, Ma Z, Tomita A. Template synthesis of novel porous carbons using various types of zeolites. Carbon 2003;41(7):1451–9. [10] Meng Y, Gu D, Zhang F, Shi Y, Yang H, Li Z, et al. Ordered mesoporous polymers and homologous carbon frameworks: amphiphilic surfactant templating and direct transformation. Angew Chem Int Ed 2005;44(43):7053–9. [11] Meng Y, Gu D, Zhang F, Shi Y, Cheng L, Feng D, et al. A family of highly ordered mesoporous polymer resin and carbon structures from organic–organic self-assembly. Chem Mater 2006;18(18):4447–64. [12] Graham LJ, Atwater EJ, Jovanovic GN. Chlorophenol dehalogenation in a magnetically stabilized fluidized bed reactor. AIChE J 2006;52(3):1083–93. [13] Yamamoto T, Endo A, Eiad-ua A, Ohmori T, Nakaiwa M, Soottitantawat A. Synthesis of monodisperse carbon beads with developed mesoporosity. AIChE J 2007;53(3):746–9. [14] Hanzawa Y, Hatori H, Yoshizawa N, Yamada Y. Structural changes in carbon aerogel with high temperature treatment. Carbon 2002;40:575–81.
4 7 ( 2 0 0 9 ) 9 2 9 –9 3 2
available at www.sciencedirect.com
journal homepage: www.elsevier.com/locate/carbon
Synthesis of monodisperse carbonaceous beads with ordered mesoporous structure Jintawat Chaichanawong, Takuji Yamamoto*, Sho Kataoka, Akira Endo, Takao Ohmori Research Institute for Innovation in Sustainable Chemistry, National Institute of Advanced Industrial Science and Technology (AIST), 1-1-1 Higashi, Tsukuba, Ibaraki 305-8565, Japan
A R T I C L E I N F O
A B S T R A C T
Article history:
Ordered mesoporous carbonaceous (OMC) beads were synthesized by a combination of the
Received 11 July 2008
syringe injection (SI) method and the evaporation-induced self-assembly (EISA) method. In
Accepted 15 November 2008
the SI method, a phenol-formaldehyde (PF) resin solution used as a carbon source is
Available online 27 November 2008
injected into an oil phase, in which the PF resin solution is insoluble, by carefully controlling the viscosity of the PF resin solution. Ordered mesoporous structure was formed based on the EISA method by adjusting the temperature for polymerization of the PF resin. Consequently, monodisperse OMC beads were obtained. Ó 2008 Elsevier Ltd. All rights reserved.
Ordered mesoporous materials are of particular interest due to their unique porous structure, which features periodic pore symmetry, large pore volume, high specific surface area, controllable mesopore distribution, and uniform pore size. These properties are potentially advantageous in many applications such as adsorption, gas separation, catalysis, water and air purification, hydrogen storage, column packing materials for high performance liquid chromatography (HPLC) and in electrical double layer capacitors [1–7]. Ordered mesoporous carbon materials have been synthesized by multi-step procedures using, for example, ordered mesoporous silica or zeolite as a hard template [8,9]. Ordered mesoporous carbon structures have recently been newly synthesized using a solvent evaporation-induced self-assembly (EISA) method that employs amphiphilic triblock copolymer (PEO-PPO-PEO) as a soft template, and phenol-formaldehyde resin as a carbon precursor [10,11]. This method avoids the use of a hard template and reduces the number of preparation steps. In various chemical processes for energy production or environmental protection, catalysts or adsorbents are often packed in a fixed-bed reactor or a column [12]. Monodisperse carbon beads are favored as packing materials for fixed-bed or fluidized-bed reactors, since they have better mechanical
strength and facilitate process design. It is therefore very important to establish a method of producing carbon beads of uniform particle size. Yamamoto et al. [13] have successfully prepared monodisperse carbon beads with developed mesoporosity using a novel method. They refer to their method as the ‘‘syringe injection (SI) method’’. The key process for obtaining monodisperse carbon beads is the controlled formation of droplets of a resorcinol-formaldehyde aqueous solution, used as a carbon precursor source, in an oil phase, in which water is insoluble, using an injection apparatus. By changing the circulation flow rate of the continuous phase, it has proved possible to control the size of the carbon beads. To the best of our knowledge, synthesis of monodisperse carbon beads with ordered mesoporous structure has not yet been reported. In the present study, a combination of the SI method [13] and the EISA method (the synthesis procedure is shown in the Supplementary information) was examined with the aim of producing monodisperse carbon beads with an ordered mesoporous structure. First, resol resin was prepared as a carbon source from phenol and formaldehyde in the manner of Meng et al. [10]. Sodium hydroxide was used as the catalyst. Then, amphiphilic triblock copolymer Pluronic F127 (BASF Japan Ltd.), dissolved
* Corresponding author: Fax: +81 29 861 4660. E-mail address: [email protected] (T. Yamamoto). 0008-6223/$ - see front matter Ó 2008 Elsevier Ltd. All rights reserved. doi:10.1016/j.carbon.2008.11.029
930
CARBON
4 7 ( 2 0 0 9 ) 9 2 9 –9 3 2
in ethanol, was mixed with the prepared resol resin. The molar ratio of phenol: formaldehyde: sodium hydroxide: F127 was fixed at 1: 2: 0.1: 0.012. After a homogeneous phenolformaldehyde (PF) resin solution was obtained, ethanol was evaporated to different extents to produce solutions with a range of viscosities. The viscosity of each solution was measured at 25 °C using an Ostwald viscometer. Beads were then synthesized from the solutions using the SI method [13]. In the SI method, the PF resin solutions are injected into silicone oil at constant speed via a syringe pump. Lengths of emerging PF resin solution were ‘snipped off’ at fixed time intervals by the pulsed flow of the silicone oil, which was circulated in a Teflon tube, creating monodisperse droplets. The droplets were kept in an oil bath at different temperatures to induce thermopolymerization (the formation of a rigid framework which can be transformed into an ordered structure by subsequent pyrolysis). The temperature of thermopolymerization was varied from 90 to 120 °C to vary the size and porous properties of the beads. The obtained beads were washed three times in cyclohexane and dried at room temperature. The
beads were then pyrolyzed in an argon gas flow at 350 °C for 3 h to obtain ordered mesoporous carbonaceous (OMC) beads. The OMC beads synthesized at 90 °C were labeled OMC-90. The OMC beads were observed using an optical microscope and the particle size distributions were determined by analyzing images of the beads. The uniformity of the beads was evaluated based on the coefficient of variation (CV), obtained by dividing the standard deviation of the particle size distribution by the mean diameter. The porous structure of OMC beads was observed using a transmission electron microscope (HF-2000 TEM, Hitachi Ltd.). The porous properties of the OMC beads were determined from the adsorption and desorption isotherms of nitrogen measured at 196 °C. In this article, the IUPAC definitions of a mesopore (dp = 2– 50 nm; dp denotes pore diameter) and a micropore (dp < 2 nm) are applied. Fig. 1a shows an image of OMC beads. The inset shows the particle size distributions (PSD) of OMC beads which were prepared after evaporating 70 or 80 wt.% of ethanol, respectively. It is noteworthy that the OMC beads have a spherical shape. The mean diameter of the beads prepared after removing 80 wt.% of ethanol was approximately 0.3 mm. Under
a a
600
OMC-90 OMC-100 OMC-110 OMC-120
Distribution [%]
70 wt.% 80 wt.%
40
400 300
3
50
q [cm (STP)/g]
500
30
200
20 10 0
100 0
0.2 0.4 0.6 Diameter [mm]
0 0
b
0.2
0.4
0.6
0.8
1
p/p0 [-] 50
b
4.0
dVp/dlog(dp) [cm /g·nm]
30
OMC-90 OMC-100 OMC-110 OMC-120
3.0
3
Viscosity [Pa·s]
40
20
10
0 0
20
40
60
80
100
Ratio of evaporated ethanol [wt.%] Fig. 1 – (a) Image of OMC beads. The inset shows the particle size distribution of OMC beads. (b) Relation between the amount of evaporated ethanol and the viscosity of PF resin solution.
2.0
1.0
0 1
10
100
dp [nm] Fig. 2 – (a) Adsorption and desorption isotherms of nitrogen on OMC beads. Closed symbols: adsorption; open symbols: desorption. (b) Pore size distributions of OMC beads.
CARBON
931
4 7 (2 0 0 9) 9 2 9–93 2
these conditions, the viscosity of the PF resin solution makes it suitable for injection. Since the corresponding CV was less than 20%, monodisperse beads were obtained. Based on our observations, uniform droplets are easily obtained only when the frequency of formation of the droplets, which detach from the tip of the needle, is synchronized with the frequency of the pulsed flow of silicone oil in the Teflon tube. If more than 80% of the ethanol was evaporated, the viscosity of the PF resin solution becomes too high to inject, as shown in Fig. 1b. In contrast, if the amount of evaporated ethanol was less than 80%, spherical beads could not be formed. A broader PSD was obtained with a CV value larger than 30%. Judging from these results, we regard the amount of ethanol in the PF resin solution as being the most important factor in controlling the particle size of the OMC beads. Fig. 2 shows adsorption and desorption isotherms of nitrogen on OMC beads and corresponding pore size distributions. They exhibit a typical type-IV isotherm with hysteresis loops and a capillary condensation step at a relative pressure about 0.4–0.8, characteristics typical of mesoporous materials. The porous properties of OMC beads were determined by applying the as-plot to the adsorption isotherm of nitrogen [14] and are summarized in Table 1. It should be noted that the porous structure of OMC-90 and OMC-100 are mainly composed of mesopores. On the other hand, some micropores are formed in OMC-110 and OMC-120. As shown in Fig. 2b, it is confirmed that the OMC beads possess a narrow pore size distribution in the mesopore range (dp 4–7 nm). OMC-110 and OMC-120 show larger pore sizes than OMC-90 and OMC-100. This
indicates that the different curing temperature affected the hydrocarbon framework structure resulting from thermopolymerization. Fig. 3 shows TEM images of OMC-90, viewed from the [1 1 1] and [1 1 0] directions. The inset shows the corresponding X-ray diffraction pattern, which confirms the formation of an ordered hexagonal mesoporous structure. The pore size of OMC-90 is approximately 5 nm, which is consistent with that determined by the nitrogen adsorption method. Based on our observations, OMC-90 possesses an ordered mesoporous structure throughout the entire bead. XRD patterns of OMC beads are shown in Fig. 4. In OMC-90 and OMC-100, an intense diffraction peak and two weak peaks were observed in a 2h range of 0.5–2.0, which confirm the existence of hexagonal structure. In addition, the XRD patterns of OMC-90 and OMC-100 show a better-resolved peak than those of OMC-110 and OMC-120. This observation indicated the high degree of ordered hexagonal structure, and also confirms that the formation of a hydrocarbon framework structure is closely dependent on the thermopolymerization temperature. At relatively high temperature (>100 °C), mesoporous structure would be deformed due to the faster polymerization rate of PF resin. In conclusion, ordered mesoporous carbonaceous (OMC) materials were synthesized in the form of beads by combining the SI method with the EISA method. The results of this study show that it is possible to prepare monodisperse OMC beads by carefully adjusting both the amount of ethanol contained in the PF resin solution used as a carbon source and the temperature used for thermopolymerization.
Table 1 – Porous properties of the prepared OMC beads. Sample
OMC-90 OMC-100 OMC-110 OMC-120
aBETa
atotalb
aextb
Vtotalb
Mesopore
2
[m /g]
2
[m /g]
2
[m /g]
[cm3/g]
amesb [m2/g]
340 394 517 513
345 387 514 518
40 49 68 47
0.37 0.38 0.60 0.57
305 338 327 352
ames/aBET [ ] 0.90 0.86 0.63 0.69
Micropore
Vmesb [cm3/g]
dpeakc [nm]
amicb [m2/g]
amic/aBET [ ]
Vmicb [cm3/g]
0.37 0.38 0.53 0.50
3.8 3.8 7.1 6.2
– – 119 119
– – 0.23 0.23
– – 0.07 0.07
a BET surface area. b Determined by using as-plot: total surface area (atotal), external surface area (aext), mesoporous surface area (ames), microporous surface area (amic), total pore volume (Vtotal), mesopore volume (Vmes) and micropore volume (Vmic). c The peak diameter of mesopores.
Fig. 3 – TEM image of OMC-90. (a) [111] direction, (b) [110] direction.
932
a
CARBON
4 7 ( 2 0 0 9 ) 9 2 9 –9 3 2
b
10
OMC-120
OMC-110
10
Intensity (a.u.)
Intensity (a.u.)
(×5 magnifications) 10
OMC-120 20 20
10
OMC-100
OMC-110 21 21
OMC-90 1
2
3
2θ (degree)
4
5
1.0
1.5
2.0
OMC-100 OMC-90 2.5
3.0
2θ (degree)
Fig. 4 – XRD patterns of OMC beads.
Acknowledgement The authors are grateful to the financial support from New Energy and Industrial Technology Development Organization (NEDO).
Appendix A. Supplementary data Supplementary data associated with this article can be found, in the online version, at doi:10.1016/j.carbon.2008.11.029.
R E F E R E N C E S
[1] Liu X, Zhou L, Li J, Sun Y, Su W, Zhou Y. Methane sorption on ordered mesoporous carbon in the present of water. Carbon 2006;44(8):1386–92.
[2] Yuan X, Zhuo SP, Wei X, Cui HY, Dai XD, Lui XM, et al. Aqueous dye adsorption on ordered mesoporous carbon. J Colloid Interface Sci 2007;310(1):83–9. [3] Wang H, Wang A, Wang X, Zhang T. One-pot synthesized MoC imbedded in ordered mesoporous carbon as a catalyst for N2H4 decomposition. Chem Commun 2008;22:2565–7. [4] Kim W, Kim P, Joo JB, Shin HK, Jung KS, Yi J. The preparation and characterization of porous carbons for hydrogen storage. J Electroceram 2006;17(2–4):679–82. [5] Armandi M, Bonelli B, Bottero I, Area´n CO, Garrone E. Synthesis and characterization of ordered porous carbons with potential applications as hydrogen storage media. Microporous Mesoporous Mater 2007;103(1–3):150–7. [6] Yuan ZY, Su BL. Insights into hierarchically mesomacroporous structured materials. J Mater Chem 2006;16:663–77. [7] Xing W, Qiao SZ, Ding RG, Li F, Lu GQ, Yan ZF, et al. Superior electric double layer capacitors using ordered mesoporous carbons. Carbon 2006;44(2):216–24. [8] Ryoo R, Joo SH, Kruk M, Jaroniec M. Ordered mesoporous carbons. Adv Mater 2001;13(9):677–81. [9] Kyotani T, Ma Z, Tomita A. Template synthesis of novel porous carbons using various types of zeolites. Carbon 2003;41(7):1451–9. [10] Meng Y, Gu D, Zhang F, Shi Y, Yang H, Li Z, et al. Ordered mesoporous polymers and homologous carbon frameworks: amphiphilic surfactant templating and direct transformation. Angew Chem Int Ed 2005;44(43):7053–9. [11] Meng Y, Gu D, Zhang F, Shi Y, Cheng L, Feng D, et al. A family of highly ordered mesoporous polymer resin and carbon structures from organic–organic self-assembly. Chem Mater 2006;18(18):4447–64. [12] Graham LJ, Atwater EJ, Jovanovic GN. Chlorophenol dehalogenation in a magnetically stabilized fluidized bed reactor. AIChE J 2006;52(3):1083–93. [13] Yamamoto T, Endo A, Eiad-ua A, Ohmori T, Nakaiwa M, Soottitantawat A. Synthesis of monodisperse carbon beads with developed mesoporosity. AIChE J 2007;53(3):746–9. [14] Hanzawa Y, Hatori H, Yoshizawa N, Yamada Y. Structural changes in carbon aerogel with high temperature treatment. Carbon 2002;40:575–81.