Based Porous Carbon Monoliths and Their Applic
Structurally
Designed
Synthesis
of
Mechanically
Stable
Poly(benzoxazine-co-resol)-Based Porous Carbon Monoliths and Their Application as High-Performance CO2 Capture Sorbents
Guang-Ping Hao, † Wen-Cui Li, † Dan Qian, † Guang-Hui Wang, † Wei-Ping Zhang, ‡ Tao Zhang, ‡ Ai-Qin Wang, ‡ Ferdi Schüth,¶ Hans-Josef Bongard,¶ and An-Hui Lu*,†
†
State Key Laboratory of Fine Chemicals, School of Chemical Engineering, Dalian
University of Technology, Dalian 16024, P. R. China ‡
State Key Laboratory of Catalysis, Dalian Institute of Chemical Physics, Chinese
Academy of Sciences, Dalian 116023, P. R. China ¶
Max-Planck-Institut für Kohlenforschung, D-45470 Mülheim an der Ruhr, Germany
*E-mail: [email protected], Tel/Fax: +86-411-84986112
Supporting Information I. Samples Characterizations……………………………………………….S2-S8 II. Calculation of CO2:N2 Selectivity…………………………………….... S9 III. Details of the Breakthrough Curve Measurements and Calculations S10-S11 IV. Heat of CO2 Adsorption Calculation………………………………….. S12 V. CO2 Sorption Tests under Humid Conditions…………………………. S12 VI. Hydrophobic Property of the Porous Carbon Monolith …………..... S13-S14
S1
I.
Samples Characterizations
Figure S1. Nitrogen sorption isotherm of the obtained carbon product synthesized by scaling up by a factor of 5, and the photograph of its as-made polymer monolith.
Figure S2. Optical image of the synthesis systems with DAH, NaOH, TMA and EDA, which were taken after polymerization for ~1 min.
S2
Figure S3. TEM image and low-angle XRD pattern of HCM-EDA.
Figure S4. Molecular structures of the organic amines.
S3
The Phenolic-based Porous Carbon. For comparison, the commonly used NaOH was also tested for the preparation of such carbon monoliths. The synthesis conditions are similar to HCM-1 (the pH of the solution was kept identical.) The nitrogen sorption isotherm shows that this carbon is a microporous material. A number of experiments has been conducted in which the NaOH amount was varied, with the aim of obtaining mesostructured carbons. However, all these attempts were unsuccessful.
Figure S5. (left side) A comparison between the two polymerization systems, poly(benzoxazine-co-resol) with “RF+DAH+F127” and phenolic resin types with “RF+NaOH+F127”; (right side) N2 isotherm of the sample obtained with NaOH and the textural parameters (inset).
The Designed Experiments to Demonstrate the Sequential Reactions. Three gels aged at 90 °C each for 15, 60 and 240 min were washed intensively with water to remove the soluble species and dried at 50 °C for 24 h. Elemental analyses show that the polymer products aged for 15 and 240 min contain 3.38 wt% S4
and 0.28 wt% of nitrogen, respectively. The latter value is close to the theoretical nitrogen content 0.32% of the synthesized polymer. To further examine whether polybenzoxazine and F127 form a stable mesostructure, the water washed polymer products were carbonized under identical conditions to those of HCM-DAH-1, and then characterized using nitrogen adsorption at 77 K (for porous parameters see Table S1). For clarity, the obtained samples were labelled I, I-wash, II, II-wash, and III, III-wash, where wash indicates the sample was intensively washed with water, and I, II and III indicate the aging time 240, 60 and 15 min, respectively. As seen in Figure S6a,b, the nitrogen isotherms for the resultant carbon products show that mesopores are present in all carbon products. In principle, the mesopores may also result from the polymer itself. To exclude that, similar experiments were conducted: three polymers (from resorcinol, formaldehyde and DAH, without using F127) were prepared by aging at 90 °C for 15, 60 and 240 min, respectively. Water washed and the original polymers were subsequently carbonized and characterized using nitrogen adsorption. For clarity, this series of samples has been denoted in a similar way to those synthesized with F127, but marked with a prime, e.g. I′, I′-wash, etc. As seen in Figure S6c, the nitrogen isotherms of all the products are of type I, indicative of microporous feature (for porous parameters see Table S1). It reveals that the presence of surfactant F127 is essential for the mesopores formation. These results confirm that the mesostructures are rapidly formed by the self-assembly of polybenzoxazine segments and surfactants, which are stable during the washing step. The presence of F127 in the water-washed polymer
S5
sample was also confirmed by TG-DTG analyses (see Figure S7). By comparing the TG-DTG curves of the polymers prepared with or without F127, and their water washed analogues, it can be seen that the DTG curves of the polymers prepared with F127 exhibit a sharp weight loss at 390 °C (typical decomposition temperature of F1271,2,3), which is a clear indication of the presence of F127 in the water washed sample.
Figure S6. (a) N2 isotherms of carbonized samples before and after H2O washing after different curing conditions, (b) the corresponding PSDs, (c) N2 isotherms of carbonized samples without using F127, before and after H2O washing after different curing conditions. The isotherms of I-wash, I, II-wash, II, III-wash, I′-wash, I′, II′, II ′-wash and III′ are vertically offset by 220, 220, 130, 50, 40, 110, 75, 60, 45 and 15 cm3g-1, STP.
S6
Figure S7. TG and DTG curves of the polymer samples prepared with and without F127, and their water washed counterparts.
Figure S8.
N2
isotherms
(a) of
HCM-DAH-1,
HCM-DAH-1-900-3, and the corresponding PSDs (b).
S7
HCM-DAH-1-900-1
and
Table S1. Pore parameters of the carbons obtained after different gelation periods and water washing treatments, followed by pyrolysis. Synthesis Conditions Sample
SBET
Dmeso
Vtotal
Vmicro
(m2g-1)
(nm)
(cm3g-1)
(cm3g-1)
Water o
Gelation at 90 C washing I (HCM-1)
240 min
no
670
5.0
0.46
0.20
I-wash
240 min
yes
852
5.5
0.59
0.26
II
60 min
no
744
5.5
0.52
0.22
II-wash
60 min
yes
804
7.4
0.49
0.29
III
15 min
no
600
5.0
0.40
0.19
III-wash
15 min
yes
719
6.4
0.41
0.27
I
240 min
no
772
--
0.38
0.32
I′-wash
240 min
yes
788
--
0.38
0.33
II’
60 min
no
732
--
0.35
0.31
II′-wash
60 min
yes
765
--
0.38
0.32
III’
15 min
no
666
--
0.33
0.28
III′-wash
15 min
yes
797
--
0.40
0.33
II. Calculation of CO2:N2 Selectivity4,5 We calculated the initial slope of the gas uptake for both N2 and CO2. The ratio of the slopes was used for calculating the selectivity at 298K.
S8
Figure S9. Initial slope calculation for CO2 and N2 isotherms collected at 298K. (a) HCM-DAH-1 (CO2: blue squares; N2: red circles), (b) HCM-DAH-1-900-1 (CO2: green squares; N2: cyan circles), (c) HCM-DAH-1-900-1 (CO2: pink squares; N2: gray circles). S9
III. Details of the Breakthrough Curve Measurements and Calculations Figure S10 shows a scheme of the setup used for the breakthrough experiments. Different gas mixtures can be prepared by a set of mass flow controllers. The gas mixture is either sent to the adsorption column, which is placed in a thermostatic water bath, or to a bypass line.
Figure S10. Scheme of the gas separation apparatus. (a) pressure controller, (b) mass flow controller, (c) pressure gauge, (d) three-way valves, (e) thermostatic water bath, (f) adsorbent column, (g) gas chromatograph, (h) three-way connection.
In practice, the experiment is conducted as follows: The adsorbent (HCM-DAH-1 of 1.700g, HCM-DAH-1-900-1 of 0.873g and HCM-DAH-1-900-2 of 0.775g) was filled into the column with a length of 100 mm and an internal diameter of 9 mm. Then it was activated in flow of Ar at a temperature of 200 oC. After keeping that temperature for 1 hour, the column was placed in a thermostatic water bath in which the temperature was set as 25 °C. The pressure in the column was maintained between 1~1.05 bar. The gas mixture was first sent to the gas chromatograph through bypass line and measured its component before the breakthrough measurements. This procedure was necessary to ensure the concentration ratio of gas mixture was CO2:N2=1:6 (v/v). Then, the flow of Ar was turned off, and a gas mixture (1:6, v/v) was sent into the sorbent column. The adsorption time and effluent flow rate was recorded every 30 seconds, and the relative amounts of the effluent gases passing through the column were monitored by GC every 4 min. After the effluent flow rate S10
and the relative amounts of the effluent gases remain unchanged, Ar flow was introduced to activate the adsorbent and then start the next round measurement. It is important to measure the dead volume when determining breakthrough time because the volume of the column and line pine could not be ignored, the gas mixture detained in column and line pine would influence the real breakthrough time. When we measured the dead volume, sand was used to replace HCM samples. The dead volume was subtracted, when we calculated the adsorption capacity.
The capacity and selectivity calculation: The (absolute) adsorbed amount is calculated from the breakthrough curve (after correction for the dead time) by the equation: t0
qi =
F0× t 0 - Vdead - ∫ Fi ∆ t 0
m
where F0=total volumetric gas flow rate (cm3min-1); t0=adsorption time (min); Vdead= dead volume of the column and line (cm3); Fi= effluent volumetric flow rate (cm3min-1); m= mass of adsorbent (g).
From the breakthrough experiments we calculated the adsorbed quantities and selectivity of the HCM series for CO2, which is defined as α=(q1/y1)/(q2/y2), where qi is the adsorbed amount of compound i and yi is the mole fraction of compound i in the gas phases.
S11
IV. Heat of CO2 Adsorption Calculation6,7 The enthalpy of CO2 adsorption onto the porous carbons was calculated using the Clausius-Clapeyron equation:
P T −T ln 1 = ∆H ads × 2 1 R × T1 × T2 P2
(I)
where Pi = pressure for isotherm i;
Ti=temperature for isotherm i; R=8.315 JK-1mol-1; which can be used to calculate the enthalpy of adsorption of a gas as a function of the quantity of gas adsorbed. Pressure as a function of the amount of CO2 adsorbed was determined by the Toth model for the isotherms (Figure 7). Q=
Qm × B
(1 ) t
(1 + B × P)
P 1
(II)
where Q=moles adsorbed; Qm= moles adsorbed at
t
saturation; P=pressure; B and t=constants; which can be used to calculate the pressure, P. Then, we can get the adsorption data, which when filled into equation (I) gives the ∆Hads.
V. CO2 Sorption Tests under Humid Conditions
Commonly, physisorbents (e.g. zeolites, MOFs, etc.) are particularly sensitive to the moisture that is abundant in typical flue gas streams. Consequently, the separation efficacy decreases drastically under humid medium. Hence, high-performance sorbents with hydrophobic properties are more suitable for specialized and industrial applications. As presented in this manuscript, our new carbon monolith shows good performance in CO2 sorption and separation under drying conditions. To extend its performance capability, we further tested its CO2 sorption and separation ability under humid condition using a gas mixture of CO2/N2/H2O (v/v/v, 14/83.5/2.5). The breakthrough results as representatively shown in Figure S11 reveal that HCM-DAH-1 provides a complete separation of CO2 from the N2 and H2O stream. From the curve, the calculated dynamic capacity is 4%, which is almost identical to that of measured under drying conditions. The measurements were repeated 3 times S12
and all gave nearly identical results.
Figure S11. Breakthrough curve of HCM-DAH-1, using a gas mixture of N2/CO2/H2O (v/v/v, 83.5/14/2.5).
VI. Hydrophobic Property of the Porous Carbon Monolith
The high-performance of such a carbon monolith under humid conditions motivated us to investigate its hydrophobic properties. We conducted the following tests. Figure S12 shows the procedure: the carbon monolith (image a) was ground into fine powder which was then filled into a container (image b) without any binder, ensuring a perfectly parallel bases; a drop of DI water (30 µL) was placed onto the sample surface (image c); the contact angle was preliminarily determined using a protractor (image d&e). The contact angle is ~128°, indicating the hydrophobic surface of HCM-DAH-1. 8 This also explains its high-performance under humid conditions.
S13
Figure S12. Photographs illustration of the hydrophobic behavior of HCM-DAH-1.
References
(1) Lu, A.-H.; Spliethoff, B.; Schüth, F. Chem. Mater. 2008, 20, 5314. (2) Wang, Y.-J.; Kim, D. J. Power Sources 2007, 166, 202. (3) Li, L.; Tsung, C.-K.; Yang, Z.; Stucky, G. D.; Sun, L.; Wang, J.; Yan C. Adv. Mater. 2008, 20, 903.
(4) Banerjee, R; Furukawa, H.; Britt, D.; Knobler, C.; O’Keeffe, M.; Yaghi, O. M. J. Am. Chem. Soc. 2009, 131, 3875. (5) An, J.; Geib, S. J.; Rosi, N. L. J. Am. Chem. Soc. 2010, 132, 38. (6) Wang, B.; Côté, A. P.; Furukawa, H.; O’Keeffe, M.; Yaghi, O. M. Nature 2008, 453, 207. (7) Malek, A.; Farooq, S. AIChE Journal 1996, 42, 3191. (8) Stein, A.; Wang, Z.; Fierke, M. A. Adv. Mater. 2009, 21, 265.
S14
Designed
Synthesis
of
Mechanically
Stable
Poly(benzoxazine-co-resol)-Based Porous Carbon Monoliths and Their Application as High-Performance CO2 Capture Sorbents
Guang-Ping Hao, † Wen-Cui Li, † Dan Qian, † Guang-Hui Wang, † Wei-Ping Zhang, ‡ Tao Zhang, ‡ Ai-Qin Wang, ‡ Ferdi Schüth,¶ Hans-Josef Bongard,¶ and An-Hui Lu*,†
†
State Key Laboratory of Fine Chemicals, School of Chemical Engineering, Dalian
University of Technology, Dalian 16024, P. R. China ‡
State Key Laboratory of Catalysis, Dalian Institute of Chemical Physics, Chinese
Academy of Sciences, Dalian 116023, P. R. China ¶
Max-Planck-Institut für Kohlenforschung, D-45470 Mülheim an der Ruhr, Germany
*E-mail: [email protected], Tel/Fax: +86-411-84986112
Supporting Information I. Samples Characterizations……………………………………………….S2-S8 II. Calculation of CO2:N2 Selectivity…………………………………….... S9 III. Details of the Breakthrough Curve Measurements and Calculations S10-S11 IV. Heat of CO2 Adsorption Calculation………………………………….. S12 V. CO2 Sorption Tests under Humid Conditions…………………………. S12 VI. Hydrophobic Property of the Porous Carbon Monolith …………..... S13-S14
S1
I.
Samples Characterizations
Figure S1. Nitrogen sorption isotherm of the obtained carbon product synthesized by scaling up by a factor of 5, and the photograph of its as-made polymer monolith.
Figure S2. Optical image of the synthesis systems with DAH, NaOH, TMA and EDA, which were taken after polymerization for ~1 min.
S2
Figure S3. TEM image and low-angle XRD pattern of HCM-EDA.
Figure S4. Molecular structures of the organic amines.
S3
The Phenolic-based Porous Carbon. For comparison, the commonly used NaOH was also tested for the preparation of such carbon monoliths. The synthesis conditions are similar to HCM-1 (the pH of the solution was kept identical.) The nitrogen sorption isotherm shows that this carbon is a microporous material. A number of experiments has been conducted in which the NaOH amount was varied, with the aim of obtaining mesostructured carbons. However, all these attempts were unsuccessful.
Figure S5. (left side) A comparison between the two polymerization systems, poly(benzoxazine-co-resol) with “RF+DAH+F127” and phenolic resin types with “RF+NaOH+F127”; (right side) N2 isotherm of the sample obtained with NaOH and the textural parameters (inset).
The Designed Experiments to Demonstrate the Sequential Reactions. Three gels aged at 90 °C each for 15, 60 and 240 min were washed intensively with water to remove the soluble species and dried at 50 °C for 24 h. Elemental analyses show that the polymer products aged for 15 and 240 min contain 3.38 wt% S4
and 0.28 wt% of nitrogen, respectively. The latter value is close to the theoretical nitrogen content 0.32% of the synthesized polymer. To further examine whether polybenzoxazine and F127 form a stable mesostructure, the water washed polymer products were carbonized under identical conditions to those of HCM-DAH-1, and then characterized using nitrogen adsorption at 77 K (for porous parameters see Table S1). For clarity, the obtained samples were labelled I, I-wash, II, II-wash, and III, III-wash, where wash indicates the sample was intensively washed with water, and I, II and III indicate the aging time 240, 60 and 15 min, respectively. As seen in Figure S6a,b, the nitrogen isotherms for the resultant carbon products show that mesopores are present in all carbon products. In principle, the mesopores may also result from the polymer itself. To exclude that, similar experiments were conducted: three polymers (from resorcinol, formaldehyde and DAH, without using F127) were prepared by aging at 90 °C for 15, 60 and 240 min, respectively. Water washed and the original polymers were subsequently carbonized and characterized using nitrogen adsorption. For clarity, this series of samples has been denoted in a similar way to those synthesized with F127, but marked with a prime, e.g. I′, I′-wash, etc. As seen in Figure S6c, the nitrogen isotherms of all the products are of type I, indicative of microporous feature (for porous parameters see Table S1). It reveals that the presence of surfactant F127 is essential for the mesopores formation. These results confirm that the mesostructures are rapidly formed by the self-assembly of polybenzoxazine segments and surfactants, which are stable during the washing step. The presence of F127 in the water-washed polymer
S5
sample was also confirmed by TG-DTG analyses (see Figure S7). By comparing the TG-DTG curves of the polymers prepared with or without F127, and their water washed analogues, it can be seen that the DTG curves of the polymers prepared with F127 exhibit a sharp weight loss at 390 °C (typical decomposition temperature of F1271,2,3), which is a clear indication of the presence of F127 in the water washed sample.
Figure S6. (a) N2 isotherms of carbonized samples before and after H2O washing after different curing conditions, (b) the corresponding PSDs, (c) N2 isotherms of carbonized samples without using F127, before and after H2O washing after different curing conditions. The isotherms of I-wash, I, II-wash, II, III-wash, I′-wash, I′, II′, II ′-wash and III′ are vertically offset by 220, 220, 130, 50, 40, 110, 75, 60, 45 and 15 cm3g-1, STP.
S6
Figure S7. TG and DTG curves of the polymer samples prepared with and without F127, and their water washed counterparts.
Figure S8.
N2
isotherms
(a) of
HCM-DAH-1,
HCM-DAH-1-900-3, and the corresponding PSDs (b).
S7
HCM-DAH-1-900-1
and
Table S1. Pore parameters of the carbons obtained after different gelation periods and water washing treatments, followed by pyrolysis. Synthesis Conditions Sample
SBET
Dmeso
Vtotal
Vmicro
(m2g-1)
(nm)
(cm3g-1)
(cm3g-1)
Water o
Gelation at 90 C washing I (HCM-1)
240 min
no
670
5.0
0.46
0.20
I-wash
240 min
yes
852
5.5
0.59
0.26
II
60 min
no
744
5.5
0.52
0.22
II-wash
60 min
yes
804
7.4
0.49
0.29
III
15 min
no
600
5.0
0.40
0.19
III-wash
15 min
yes
719
6.4
0.41
0.27
I
240 min
no
772
--
0.38
0.32
I′-wash
240 min
yes
788
--
0.38
0.33
II’
60 min
no
732
--
0.35
0.31
II′-wash
60 min
yes
765
--
0.38
0.32
III’
15 min
no
666
--
0.33
0.28
III′-wash
15 min
yes
797
--
0.40
0.33
II. Calculation of CO2:N2 Selectivity4,5 We calculated the initial slope of the gas uptake for both N2 and CO2. The ratio of the slopes was used for calculating the selectivity at 298K.
S8
Figure S9. Initial slope calculation for CO2 and N2 isotherms collected at 298K. (a) HCM-DAH-1 (CO2: blue squares; N2: red circles), (b) HCM-DAH-1-900-1 (CO2: green squares; N2: cyan circles), (c) HCM-DAH-1-900-1 (CO2: pink squares; N2: gray circles). S9
III. Details of the Breakthrough Curve Measurements and Calculations Figure S10 shows a scheme of the setup used for the breakthrough experiments. Different gas mixtures can be prepared by a set of mass flow controllers. The gas mixture is either sent to the adsorption column, which is placed in a thermostatic water bath, or to a bypass line.
Figure S10. Scheme of the gas separation apparatus. (a) pressure controller, (b) mass flow controller, (c) pressure gauge, (d) three-way valves, (e) thermostatic water bath, (f) adsorbent column, (g) gas chromatograph, (h) three-way connection.
In practice, the experiment is conducted as follows: The adsorbent (HCM-DAH-1 of 1.700g, HCM-DAH-1-900-1 of 0.873g and HCM-DAH-1-900-2 of 0.775g) was filled into the column with a length of 100 mm and an internal diameter of 9 mm. Then it was activated in flow of Ar at a temperature of 200 oC. After keeping that temperature for 1 hour, the column was placed in a thermostatic water bath in which the temperature was set as 25 °C. The pressure in the column was maintained between 1~1.05 bar. The gas mixture was first sent to the gas chromatograph through bypass line and measured its component before the breakthrough measurements. This procedure was necessary to ensure the concentration ratio of gas mixture was CO2:N2=1:6 (v/v). Then, the flow of Ar was turned off, and a gas mixture (1:6, v/v) was sent into the sorbent column. The adsorption time and effluent flow rate was recorded every 30 seconds, and the relative amounts of the effluent gases passing through the column were monitored by GC every 4 min. After the effluent flow rate S10
and the relative amounts of the effluent gases remain unchanged, Ar flow was introduced to activate the adsorbent and then start the next round measurement. It is important to measure the dead volume when determining breakthrough time because the volume of the column and line pine could not be ignored, the gas mixture detained in column and line pine would influence the real breakthrough time. When we measured the dead volume, sand was used to replace HCM samples. The dead volume was subtracted, when we calculated the adsorption capacity.
The capacity and selectivity calculation: The (absolute) adsorbed amount is calculated from the breakthrough curve (after correction for the dead time) by the equation: t0
qi =
F0× t 0 - Vdead - ∫ Fi ∆ t 0
m
where F0=total volumetric gas flow rate (cm3min-1); t0=adsorption time (min); Vdead= dead volume of the column and line (cm3); Fi= effluent volumetric flow rate (cm3min-1); m= mass of adsorbent (g).
From the breakthrough experiments we calculated the adsorbed quantities and selectivity of the HCM series for CO2, which is defined as α=(q1/y1)/(q2/y2), where qi is the adsorbed amount of compound i and yi is the mole fraction of compound i in the gas phases.
S11
IV. Heat of CO2 Adsorption Calculation6,7 The enthalpy of CO2 adsorption onto the porous carbons was calculated using the Clausius-Clapeyron equation:
P T −T ln 1 = ∆H ads × 2 1 R × T1 × T2 P2
(I)
where Pi = pressure for isotherm i;
Ti=temperature for isotherm i; R=8.315 JK-1mol-1; which can be used to calculate the enthalpy of adsorption of a gas as a function of the quantity of gas adsorbed. Pressure as a function of the amount of CO2 adsorbed was determined by the Toth model for the isotherms (Figure 7). Q=
Qm × B
(1 ) t
(1 + B × P)
P 1
(II)
where Q=moles adsorbed; Qm= moles adsorbed at
t
saturation; P=pressure; B and t=constants; which can be used to calculate the pressure, P. Then, we can get the adsorption data, which when filled into equation (I) gives the ∆Hads.
V. CO2 Sorption Tests under Humid Conditions
Commonly, physisorbents (e.g. zeolites, MOFs, etc.) are particularly sensitive to the moisture that is abundant in typical flue gas streams. Consequently, the separation efficacy decreases drastically under humid medium. Hence, high-performance sorbents with hydrophobic properties are more suitable for specialized and industrial applications. As presented in this manuscript, our new carbon monolith shows good performance in CO2 sorption and separation under drying conditions. To extend its performance capability, we further tested its CO2 sorption and separation ability under humid condition using a gas mixture of CO2/N2/H2O (v/v/v, 14/83.5/2.5). The breakthrough results as representatively shown in Figure S11 reveal that HCM-DAH-1 provides a complete separation of CO2 from the N2 and H2O stream. From the curve, the calculated dynamic capacity is 4%, which is almost identical to that of measured under drying conditions. The measurements were repeated 3 times S12
and all gave nearly identical results.
Figure S11. Breakthrough curve of HCM-DAH-1, using a gas mixture of N2/CO2/H2O (v/v/v, 83.5/14/2.5).
VI. Hydrophobic Property of the Porous Carbon Monolith
The high-performance of such a carbon monolith under humid conditions motivated us to investigate its hydrophobic properties. We conducted the following tests. Figure S12 shows the procedure: the carbon monolith (image a) was ground into fine powder which was then filled into a container (image b) without any binder, ensuring a perfectly parallel bases; a drop of DI water (30 µL) was placed onto the sample surface (image c); the contact angle was preliminarily determined using a protractor (image d&e). The contact angle is ~128°, indicating the hydrophobic surface of HCM-DAH-1. 8 This also explains its high-performance under humid conditions.
S13
Figure S12. Photographs illustration of the hydrophobic behavior of HCM-DAH-1.
References
(1) Lu, A.-H.; Spliethoff, B.; Schüth, F. Chem. Mater. 2008, 20, 5314. (2) Wang, Y.-J.; Kim, D. J. Power Sources 2007, 166, 202. (3) Li, L.; Tsung, C.-K.; Yang, Z.; Stucky, G. D.; Sun, L.; Wang, J.; Yan C. Adv. Mater. 2008, 20, 903.
(4) Banerjee, R; Furukawa, H.; Britt, D.; Knobler, C.; O’Keeffe, M.; Yaghi, O. M. J. Am. Chem. Soc. 2009, 131, 3875. (5) An, J.; Geib, S. J.; Rosi, N. L. J. Am. Chem. Soc. 2010, 132, 38. (6) Wang, B.; Côté, A. P.; Furukawa, H.; O’Keeffe, M.; Yaghi, O. M. Nature 2008, 453, 207. (7) Malek, A.; Farooq, S. AIChE Journal 1996, 42, 3191. (8) Stein, A.; Wang, Z.; Fierke, M. A. Adv. Mater. 2009, 21, 265.
S14
