Monodentate hydroxide as a super strong yet reversible ...Monodentate hydroxide as a super strong yet reversible active site for CO2 capture from high-humidity flue gas Pei-Qin Liao,

ESI

Monodentate hydroxide as a super strong yet reversible active site for CO2 capture from high-humidity flue gas Pei-Qin Liao, Huayao Chen, Dong-Dong Zhou, Si-Yang Liu, Chun-Ting He, Zebao Rui, Hongbing Ji, Jie-Peng Zhang* and Xiao-Ming Chen

MOE Key Laboratory of Bioinorganic and Synthetic Chemistry, School of Chemistry and Chemical Engineering, Sun Yat-Sen University, Guangzhou 510275, China.

*E-mail: [email protected]

Electronic Supplementary Material (ESI) for Energy & Environmental Science.This journal is © The Royal Society of Chemistry 2015

Supplementary Index Experimental details.

Scheme S1. Representation of the column breakthrough experiment.

Figure S1. Thermogravimetry curves of 1, 1', 2, and 2'.

Figure S2. Rietveld refinement plots of 1, 1', 2, and 2'.

Figure S3. IR spectra of 1, 1', 2, and 2'.

Figure S4. XPS spectra of 2 and 2'.

Figure S5. EPR spectra of 1 and 1'.

Figure S6. N2 isotherms of 1, 1', 2, and 2' measured at 77 K.

Figure S7. Comparison of the CO2 adsorption isotherms between 1 and 2 and between 1' and 2'

measured at 298 K.

Figure S8. CO2 sorption isotherms of 1 and 1'.

Figure S9. The obtained Virial and dual-site Langmuir-Freundlich fitting parameters of 1.

Figure S10. The obtained Virial and dual-site Langmuir-Freundlich fitting parameters of 1'.

Figure S11. CO2 sorption isotherms of 2 and 2'.

Figure S12. The obtained Virial and dual-site Langmuir-Freundlich fitting parameters of 2.

Figure S13. The obtained Virial and dual-site Langmuir-Freundlich fitting parameters of 2'.

Figure S14. Coverage-dependent CO2 adsorption enthalpy of 1, 1', 2 and 2'.

Figure S15. In situ IR spectra of 2' with varied atmosphere measured at 313 K.

Figure S16. N2 sorption isotherms of 1, 1', 2 and 2' measured at 298 K.

Figure S17. The CO2 adsorption and desorption behaviors of 1' under mixed gas and kinetic conditions.

Figure S18. Heat flows of 2' determined via DSC.

Figure S19. Breakthrough curves of Fig. 4 expressed using time (min) as abscissa.

Figure S20. Breakthrough curves of Fig. 4 expressed using specific breakthrough time (min g-1) as

abscissa.

Table S1. Performance of selected PCPs for CO2 capture.

Table S2. Crystallographic data and structure refinement results.

Table S3. Elemental analyses.

Table S4. Comparing the performance of capturing CO2 from simulated flue gas of 1' and 2' with the

highest reported values.

Experimental details. Materials and General Methods. Reagents and solvents were commercially available and were used without further

purification. The ligand H2bbta was synthesized according to the literature method.[H. Hart, D. Ok, J. Org. Chem. 1986, 51, 979.] The concentration

of hydrochloric acid is 12 M, and the concentration of H2O2 is 8.8 M. Thermogravimetric analyses were performed under N2

with temperature increased with 10 oC min–1 using a TA-Q50 system. PXRD patterns were collected (0.02 o/step, 0.06

seconds/step) on a Bruker D8 Advance diffractometer (Cu Kα) at room temperature. XPS measurements were performed with

a VG Scientific ESCALAB 250 instrument. Magnetic susceptibility measurements were performed with a Quantum Design

MPMS-XL7 SQUID instrument. Electron paramagnetic resonance (EPR) measurements were performed at 9.7 GHz (X-band)

using a Bruker BioSpin A300 spectrometer at 77 K. The spin concentrations in the samples were determined from the second

integral of the spectra using CuSO4·5H2O as a standard. Differential scanning calorimetry (DSC) measurements were

performed in the temperature range 313-383 K on a TA-Q2000 DSC instrument. Diffused Reflection Fourier Transform

Infrared Spectra (DR-FTIR) were measured by a Bruker VERTEX 70 spectrometer in the 400–4000 cm–1 region.

Synthesis of [Mn2Cl2(bbta)] (1 or MAF-X25). A mixture of MnCl2·4H2O (0.050 g, 0.252 mmol) and H2bbta (0.020 g,

0.126 mmol) was dissolved in a 100:100:1 (v/v/v) mixture of DMF-methanol-HCl (8 mL) in a 15-mL Teflon reactor, which

was heated in an oven at 70 °C for 72 h and then cooled to room temperature at a rate of 5 °C h−1. The obtained mixture was

filtered, successively washed by H2O and MeOH twice, soaked in MeOH for two days, filtered, and finally heated at 100 oC

for 10 h to give light purple microcrystalline powder (yield 72% based on H2bbta). See Table S3 for elementary analysis.

Synthesis of [Mn2Cl2(bbta)(OH)] (1' or MAF-X25ox). A solution of H2O2 (0.5 mmol) in water (10 mL) was slowly

added in 12 h to a suspension of 1 (0.0169 g, 0.05 mmol) in a mixed solvent of CH3CN (5.0 mL), water (5.0 mL), and

triethylamine (0.02 mL) at 0 °C under stirring, during which the color of the suspension turned brown gradually. The mixture

was further stirred for 2 days at room temperature, and then filtered, washed by CH3CN and dried in N2 flow, and finally

heated at 100 oC for 10 h to give dark green microcrystalline powder (0.0152 g, yield 97%). See Table S3 for elementary

analysis.

Synthesis of [Co2Cl2(bbta)] (2 or MAF-X27). A mixture of CoCl2·6H2O (0.030 g, 0.126 mmol), H2bbta (0.020 g, 0.126

mmol) was dissolved in a 100:100:1 (v/v/v) mixture of DMF-methanol-HCl (8 mL) in a 15-mL Teflon reactor, which was

heated in an oven at 70 °C for 72 h and then cooled to room temperature at a rate of 5 °C h−1. The obtained mixture was

filtered, successively washed by H2O and MeOH twice, soaked in MeOH for two days, filtered, and finally heated at 100 oC

for 10 h to give pink microcrystalline powder (yield: 85%). See Table S3 for elementary analysis.

Synthesis of [Co2Cl2(bbta)(OH)] (2' or MAF-X27ox). A solution of H2O2 (0.5 mmol) in water (10 mL) was slowly added

in 12 h to a suspension of 2 (0.0171 g, 0.05 mmol) in CH3CN (5.0 mL), water (5.0 mL), and triethylamine (0.02 mL) at 0 °C

under stirring, during which the color of the suspension turned from red to brown-red gradually. The mixture was further

stirred for 12 h at room temperature, and then filtered, washed by CH3CN and dried in N2 flow, and finally heated at 100 oC for

10 h to give yellow microcrystalline powder (0.0156 g, yield 98%). See Table S3 for elementary analysis.

X-ray Crystallography. Because single-crystal specimen cannot be obtained for 2 or 2' so far, their crystal structures were

solved by the Rietveld refinement of their powder X-ray diffraction data. To confirm the good crystallinity and purity of all

samples, the Rietveld refinement was also applied to microcrystalline samples of 1 and 1'. The microcrystalline samples were

placed in a glass capillary (Φ = 0.70 mm), and heated under high vacuum at 373 K for 24 h. After that, the capillary was sealed

by a torch. The PXRD patterns were collected (0.02 o/step, 10 seconds/step) on a Bruker D8 Advance diffractometer (Cu Kα)

at room temperature.

Pawley and Rietveld refinements were performed by the Reflex plus module of Material Studio. Pawley refinements were

performed in the 2θ range of 6–70o on unit-cell parameters, zero point and background terms with Pseudo-Voigt profile

function and Berar-Baldinozzi asymmetry correction function under the R-3m space group, yielding the following parameters:

a = 25.39(2) Å, c = 8.543(7) Å, Rp = 1.79%, Rwp = 2.41% for 1, a = 24.60(1) Å, c = 8.320(4) Å, Rp = 0.70%, Rwp = 1.35% for

1', a = 24.739(19) Å, c = 8.179(6) Å, Rp = 0.73%, Rwp = 1.25% for 2 and a = 24.086(30) Å, c = 7.804(10) Å, Rp = 0.54%, Rwp

= 0.80% for 2'. Rietveld refinements were performed in the 2θ range of 6−70 degree. The initial structural models were

produced by referring the reported single-crystal structure of 1. In each refinement, the structures of 1/2 and 1'/2' were divided

into 3 (metal ion, chloride ion, and organic ligand) and 4 (metal ion, chloride ion, organic ligand, and hydroxide) rigid

fragments that allowed for motion. These structural freedoms (including the occupancy of the hydroxide anion) together with

the pseudo-Voigt profile parameters, background parameters, the cell parameters, the zero point of the diffraction pattern, the

global isotropic atom displacement parameters, the Berar–Baldinozzi asymmetry correction parameters, and the March–

Dollase preferred orientation correction parameters, were optimized step by step to improve the agreement between the

calculated and the experimental powder diffraction patterns. The refinements gave hydroxide occupancies of 0.46 for 1' and

0.47 for 2', which were similar to those evaluated by the N2 isotherm, XPS, and/or magnetic susceptibility measurements (The

χmT products of each Co(II) at 300 K of 2 and 2' are 2.57 and 1.42 cm3 K mol-1 (χmT product of low-spin Co(III) is zero)

respectively, indicating that Co(III) ion in 2' is about 45%. On the other hand, since both Mn(II) and Mn(III) are paramagnetic

with multiple unpaired electrons, their relative ratio can be hardly determined by magnetic susceptibility.). Finally, the

occupancies of hydroxide were fixed as 0.5, and other parameters were continued to be optimized until the best agreement

between the calculated and the experimental powder diffraction patterns (Figure S1). Crystal data were summarized in Table

S2.

Gas Sorption Measurements. The sorption isotherms were measured with automatic volumetric adsorption apparatuses

(Micromertics ASAP 2020M and BELSORP-max). The as-synthesized sample (weight of about 100−200 mg) was placed in

the sample tube and dried for 12 h at 100 °C to remove the remnant solvent molecules prior to measurements. Ultrahigh-

purity-grade (99.999%) N2 and CO2 were used for all measurements. The temperatures were controlled by a liquid-nitrogen

bath (77 K) or a water bath (298, 308, 313, 318 and 328 K).

CO2/N2 breakthrough curve measurements. A stainless-steel column with a length of 10 cm and an internal diameter of

0.46 cm (Vcolumn = 0.230×0.230×3.14×10.0 = 1.66 cm3) was packed with microcrystalline sample (Scheme S1). The column

contained 1.574 g of 2' or 1.424 g of 2, corresponding to apparent densities of 0.948 and 0.858 g cm–3, and column voidages of

1-0.948/1.354 = 0.300 and 1-0.858/1.138 = 0.246, respectively. The column was connected to the injection and sampling ports

by stainless-steel pipes with a combined length of 40 cm and an internal diameter of 0.30 cm (Vtube = 0.150×0.150×3.14×40 =

2.84 cm3). The column and most parts of the pipelines between the injection and sampling ports were placed in a temperature-

controlling oven. The flow rates (mL min–1 at 298.15 K and 101.325 kPa) of pure gases were regulated by mass flow

controllers. Before breakthrough experiments, the columns were activated by passing He (10 mL min–1) and heated at 373 K

for 10 hours, and then cooled to the measurement temperature of 313(1) K. Pure N2 (1.8 mL min–1) and CO2 (0.2 mL min-1)

were mixed and then used directly as dry (0% RH) or passed through a water vapor saturator at 310 K as wet (82(3)% RH) gas

mixture for the injection port. Prior to the breakthrough measurements in the presence of high humidity, wet He was

introduced to the adsorbent bed until water saturation was detected. Then the wet He was switched to wet 10:90 CO2/N2

mixture to start the breakthrough experiment. The temperature and realative humidity was measured by a digital temperature-

humidity sensor. The gas stream at the outlet of the column was analyzed on line by using a chromatographic analyzer (Agilent

7890A) with a TCD detector and a PLOT/Q column. Before injection of CO2/N2 mixture, the column and pipeline contained

He of V = 1.66×0.30 + 1.574/1.354×54% + 2.84 = 3.97 cm3, i.e., 3.97×0.1×273/313/22.4/1.574 = 0.00982 mmol g–1 for 2'; or

V = 1.66×0.246 + 0.754/1.138×54% + 2.84 = 3.61 cm3, i.e., 3.61×0.1×273/313/22.4/1.424 = 0.00987 mmol g–1 for 2.

The amount of CO2 (q) retained by the column at a particular specific injection amount τ, can be calculated by

0( ) 0.1*( ( )d ) q f

ττ τ τ τ= − ∫

where the breakthrough curve is expressed by the function f(τ).

The CO2 adsorbed by the adsorbent in the column (Q) can be calculated by

cQ q q= −

where the qc is the gas part of the column and the gas in the pipeline.

For example, integration of the experimental breakthrough curve of CO2 for 2', either at 0% or 82(3)% RH, indicate that q

reaches saturation of 2.49 mmol g–1 when τ > 28 mmol g–1; so that Q = 2.49 – 0.01 = 2.48 mmol g–1.

Calculation of approximate regeneration energy. The specific heat (1.4 J g−1 K−1) of 2' was measured by DSC. The

sensible heat required for regeneration (98 J g−1) is the specific heat (1.4 J g−1 K−1) multiplied by the temperature change (70 K,

see Fig. S18). The working capacity was obtained as 2.0 mmol g−1 between 15:85 CO2/N2 (v/v) mixture at 313 K and a pure

CO2 flow at 383 K. To remove this CO2, approximately 144 J g−1 (obtaining via the integration of the coverage-dependent CO2

adsorption enthalpy curve) are required. To adsorb 1 kg (22.72 mol) of CO2, 11 kg of 2' are necessary. Thus, the regeneration

energy is:

11 kg* (98 kJ kg−1+ 144 kJ kg−1) = 2.7 MJ kg−1 CO2.

Scheme S1. Representation of the column breakthrough experiment.

100 200 300 400 500 600 700 800 900

30405060708090

100

Wei

ght (

%)

Temperature (oC)

(a)

100 200 300 400 500 600 700 800 900

2030405060708090

100

Mas

s Cha

nge

(%)

Temperature (oC)

(b)

100 200 300 400 500 600 70040

50

60

70

80

90

100

Mas

s Cha

nge

(%)

Temperature (oC)

(c)

100 200 300 400 500 600 700 800 900

20

30

40

50

60

70

80

90

100

Mas

s Cha

nge

(%)

Temperature (oC)

(d)

Figure S1. (a-d) TG curves of 1, 2, 1' and 2'.

10 20 30 40 50 60 70

Synthesized Simulated Difference Background Obsered Reflection

2 Theta (degree)

(a)

10 20 30 40 50 60 70


2 Theta (degree)

(b)

10 20 30 40 50 60 70


2 Theta (degree)

(c)

10 20 30 40 50 60 70


2 Theta (degree)

(d)

Figure S2. Rietveld refinement plot of (a) 1, (b) 1', (c) 2, and (d) 2'. Before measurement of the PXRD data, the samples were

heated at 373 K, respectively, according to the thermogravimetry curves as shown in Figure S1.

4000 3500 3000 2500 2000 1500 1000 500Wavenumber (cm-1)

(a)

1'

1

υ (O-H)

4000 3500 3000 2500 2000 1500 1000 500

(b)

υ (O-H)

2

2'

Wavenumber (cm-1)

Figure S3. IR spectra of (a) 1/1' and (b) 2/2'. The samples were in situ desolvated before measurement.

820 810 800 790 780 770

Co 2P2/3Co 2P1/2

Shake-up

Binding Energy (eV)

(a)

820 810 800 790 780 770

Co 2P2/3Co 2P1/2

Shake-up

Binding Energy (eV)

(b)

Figure S4. XPS spectra of (a) 2 and (b) 2'. The binding energies of Co 2P2/3 (781.7 eV) and Co 2P1/2 (797.4 eV) as well as the

shake-up satellite peaks in the XPS of 2 confirm the oxidation state of +2 for cobalt.[Biesinger, M. C. et al. Appl. Surf. Sci. 2011, 257, 2717] The

ratio of peak areas (deconvoluted by the Gaussian-Lorentzian function) between the shake-up satellite peak (781.7 eV) and its

main peak at 797.4 eV is 1.2 for 2 and 0.53 for 2', indicating that the proportion of Co(III) ion in 2' is about 55%.

1 2 3 4 5 6 7

1

g

1'

Figure S5. EPR spectra of 1 (black) and 1' (red). The strong broad EPR signal with g = 1.997 demonstrated that the presence

of Mn(II) species in 1. On the other hand, the EPR spectrum of 1' was silent, indicating the presence of Mn(III) in 1'. The EPR

signal of Mn(II) in 1' was not observed, which could be attributed to the relatively high measurement temperature (77 K) and

the changed coordination environment.

0.0 0.2 0.4 0.6 0.8 1.00

70

140

210

280

350

420G

as U

ptak

e (cm

3 g-1

)

Pressure (bar)

(a)

1'

1

0.0 0.2 0.4 0.6 0.8 1.0

0

60

120

180

240

300

360

2'

2

Gas

Upt

ake

(cm

3 g-1

)

Pressure (bar)

(b)

Figure S6. N2 isotherms measured at 77 K. Assuming the oxidation ratio is 100%, the crystallography pore volumes of 1' and

2' can be calculated as 0.38 cm3 g−1 (void = 48.4%, Dc = 1.285 g cm–3) and 0.32 cm3 g−1 (void = 46.8%, Dc = 1.452 g cm−3),

corresponding to saturated N2 uptakes of 243 and 205 cm3 g–1, respectively. Assuming the oxidation ratio of 50%, the

crystallography pore volumes of 1' and 2' were 0.44 cm3 g−1 and 0.40 cm3 g−1, corresponding to saturated N2 uptakes of 282

and 256 cm3 g–1, respectively (Table S2).

0.01 0.1 10.0

0.4

0.8

1.2

1.6

2.0 1 2

Gas

Upt

ake

(mm

ol m

mol

-1)

Pressure (bar)

(a)

1E-4 1E-3 0.01 0.1 1

10

100

1' 2'

Pressure (bar)

Gas

Upt

ake

(cm

3 g-1

)

(b)

Figure S7. Comparison of the CO2 adsorption isotherms between 1 and 2 and between 1' and 2' measured at 298 K.

0.0 0.2 0.4 0.6 0.8 1.00

1

2

3

4

5

Pressure (bar)

Gas

Upt

ake

(mm

ol g

-1)

(a)

0.0 0.2 0.4 0.6 0.8 1.0

012345678(b)

Pressure (bar)

Gas

Upt

ake

(mm

ol g

-1)

Figure S8. (a) CO2 adsorption (solid) and desorption (open) isotherms of (a) 1 measured at 298 (black), 308 (red) and 318 K

(blue) and (b) 1' measured at 298 (black), 313 (red) and 328 K (blue).

0 1 2 3 4 5

6

7

8

9

10

11

12

Equation y = ln(x) + 1/T*(a0+a1*x+a2*x^2+a3*x^3+a4*x^4+ a5*Adj. R-Square 0.9976

Value Standard ErrorD T 298 0D a0 -4681.2904 210.32595D a1 3334.50975 593.49284D a2 -1946.67365 467.09574D a3 573.94616 287.57726D a4 -147.70537 156.50743D a5 36.37052 47.74899D a6 -4.82601 7.34502D a7 0.26274 0.44781D b0 24.85571 0.67784D b1 -9.58868 1.87287D b2 4.71981 1.22432D b3 -0.72035 0.21806H T 308 0L T 318 0

n (mmol g-1)

ln p

(ln

Pa)

(a)

0.0 0.2 0.4 0.6 0.8 1.0

0

1

2

3

4

5

Pressure (bar)

n (m

mol

g-1

)

(b)

Equation y = (Q1*b1*x^(1/t1)/(1+b1*x^(1/t1)))+(Q2*b2*x^(1/t2)/(1+b2*x^(1/t2)))

Adj. R-Square 0.99999 298 KValue Standard Error

B Q1 13.88015 0.01412B b1 0.23293 0.0225B Q2 4.08057 0.5464B b2 1.11208 0.09504B t1 1.31078 0.04115B t2 0.59042 0.02717

0.0 0.2 0.4 0.6 0.8 1.00

1

2

3

4

Pressure (bar)

n (m

mol

g-1

)

(c)


Adj. R-Squar 0.99992 308 KValue Standard Error

D Q1 12.3639 1.55099D b1 0.43589 0.06621D Q2 0.22536 0.08164D b2 15.9015 0.95259D t1 0.82767 0.04266D t2 1.03272 0.09367

0.0 0.2 0.4 0.6 0.8 1.0

0.0

0.5

1.0

1.5

2.0

2.5

3.0

3.5

n (m

mol

g-1

)

Pressure (bar)

(d)



F Q1 3.74775 0.77445F b1 0.42052 0.07097F Q2 6.6217 0.35828F b2 0.41197 0.03205F t1 0.53676 0.04295F t2 1.10221 0.02628

Figure S9. (a) Virial fitting (lines) of the CO2 adsorption isotherms (points) of 1 measured at 298 (black), 308 (red) and 318 K

(blue). (b-d) Dual-site Langmuir-Freundlich fitting (lines) of the CO2 adsorption isotherms (points) of 1 measured at 298

(black), 308 (red) and 318 K (blue).

0 1 2 3 4 5 6 7 82

4

6

8

10

12

ln p

(ln

Pa)

(a)

n (mmol g-1)

Equation y = ln(x) + 1/T*(a0+a1*x+a2*x^2+a3*x^3+a4*x^4+Adj. R-Square 0.99795 Value Standard ErrorG1 T 298 0G1 a0 -12268.40326 442.95968G1 a1 3491.78143 609.01758G1 a2 -370.99467 226.52859G1 a3 0.58707 30.30898G1 a4 1.2046 3.2846G1 a5 -0.11357 0.18235G1 b0 42.8826 1.39779G1 b1 -8.09603 1.92234G1 b2 0.56411 0.70164G1 b3 0.03441 0.07397I1 T 313 0H T 328 0

0.0 0.2 0.4 0.6 0.8 1.00

2

4

6

8

Pressure (bar)

n (m

mol

g-1

)

(b)


Adj. R-Square 0.99994 Value Standard ErrorG1 Q1 7.59055 0.3452G1 b1 1.81872 0.10669G1 Q2 2.32869 0.16269G1 b2 27.52566 8.23567G1 t1 1.10028 0.04147G1 t2 1.93097 0.09662

0.0 0.2 0.4 0.6 0.8 1.00

1

2

3

4

5

6(b)

n (m

mol

g-1

)

Pressure (bar)


Adj. R-Squar 0.9999 Value Standard ErrorI1 Q1 9.47562 0.34817I1 b1 1.20274 0.08233I1 Q2 1.02973 0.02802I1 b2 846.39466 27.6918I1 t1 1.2405 0.03184I1 t2 1.03532 0.00775

0.0 0.2 0.4 0.6 0.8 1.0

0

1

2

3

4

5

Pressure (bar)

n (m

mol

g-1

)

(d)


Adj. R-Squar 0.99997 Value Standard ErrorH Q1 7.15755 0.13131H b1 1.4943 0.0537H Q2 0.76397 0.01689H b2 551.74614 11.99847H t1 1.14354 0.01737H t2 0.95558 0.0059

Figure S10. (a) Virial fitting (lines) of the CO2 adsorption isotherms (points) of 1' measured at 298 (black), 313 (red) and 328

K (blue). (b-d) Dual-site Langmuir-Freundlich fitting (lines) of the CO2 adsorption isotherms (points) of 1' measured at 298


0.0 0.2 0.4 0.6 0.8 1.00

1

2

3

4

5

Gas

Upt

ake

(mm

ol g

-1)

Pressure (bar)

(a)

0.0 0.2 0.4 0.6 0.8 1.0

0

1

2

3

4

5

6

7

Gas

Upt

ake

(mm

ol g

-1)

Pressure (bar)

(b)

Figure S11. (a) CO2 adsorption (solid) and desorption (open) isotherms of 2 (a) measured at 298 (black), 308 (red) and 318 K

(blue) and 2' (b) measured at 298 (black), 313 (red) and 328 K (blue).

0 1 2 3 42

4

6

8

10

12

ln p

(ln

Pa)

n (mmol g-1)

(a)

Equation y = ln(x)+1/T*(a0+a1*x+a2*x^2+a3*x^3+a4*Adj. R-Square 0.99962 Value Standard Error

-- a0 -3407.10274 91.17378-- a1 860.02219 313.99736-- a2 -402.7704 246.63899-- a3 -94.27929 74.37619-- a4 89.85193 32.27021-- a5 -17.35437 7.03374-- a6 1.28037 0.57537-- b0 21.40938 0.2953-- b1 -3.31785 1.02511-- b2 2.22641 0.81858-- b3 -0.42339 0.17569-- T 298 0-- T 308 0-- T 318 0

0.0 0.2 0.4 0.6 0.8 1.00

1

2

3

4

5

Pressure (bar)

n (m

mol

g-1

)

(b)


Adj. R-Square 1 298 KValue Standard Error

B Q1 11.6889 0.85583B b1 0.47313 0.03098B Q2 0.64004 0.21676B b2 2.74715 0.88986B t1 0.9704 0.00601B t2 0.38644 0.03811

0.0 0.2 0.4 0.6 0.8 1.00.0

0.5

1.0

1.5

2.0

2.5

3.0

3.5

Pressure (bar)

n (m

mol

g-1

)

(c)



D Q1 9.3477 0.50946D b1 0.47625 0.02105D Q2 0.31569 0.09533D b2 10.62598 3.85579D t1 0.76706 0.02397D t2 0.8919 0.03697

0.0 0.2 0.4 0.6 0.8 1.0

0.0

0.5

1.0

1.5

2.0

2.5



F Q1 7.84801 1.25834F b1 0.36546 0.04043F Q2 0.4749 0.24149F b2 5.03612 2.0971F t1 0.72448 0.05921F t2 0.93456 0.02444

Pressure (bar)

n (m

mol

g-1

)

(d)

Figure S12. (a) Virial fitting (lines) of the CO2 adsorption isotherms (points) of 2 measured at 298 (black), 308 (red) and 318

K (blue). (b-d) Dual-site Langmuir-Freundlich fitting (lines) of the CO2 adsorption isotherms (points) of 2 measured at 298


0 1 2 3 4 5 6 7

2

4

6

8

10

12

n (mmol g-1)

ln p

(ln

Pa)

(a)

Equation y = ln(x) + 1/T*(a0+a1*x+a2*x^2+a3*x^3+a4*x^4Adj. R-Square 0.99726 Value Standard ErrorD T 298 0D a0 -13544.99594 510.62764D a1 5345.49331 719.78748D a2 -700.93782 278.06006D a3 -106.70283 38.32722D a4 30.68509 4.16277D a5 -1.81969 0.24704D b0 46.79718 1.59103D b1 -15.21097 2.21936D b2 3.06146 0.8339D b3 -0.19742 0.09081H T 313 0L T 328 0

0.0 0.2 0.4 0.6 0.8 1.0

0

1

2

3

4

5

6

7

n (m

mol

g-1

)

(b)

Pressure (bar)



B Q1 6.8728 0.09277B b1 3.07111 0.10244B Q2 1.54799 0.02801B b2 145.65327 3.08581B t1 1.16485 0.01806B t2 1.6173 0.01325

0.0 0.2 0.4 0.6 0.8 1.00

1

2

3

4

5

6(c)

n (m

mol

g-1

)

Pressure (bar)


Adj. R-Squar 0.99993 313 KValue Standard Error

D Q1 5.8032 0.08233D b1 2.88246 0.10374D Q2 1.61231 0.02073D b2 81.72183 1.30641D t1 0.92497 0.01466D t2 1.47788 0.00906

0.0 0.2 0.4 0.6 0.8 1.0

0

1

2

3

4

5n

(mm

ol g

-1)

(d)

Pressure (bar)



F Q1 6.86251 0.14507F b1 0.91503 0.06136F Q2 1.55121 0.01607F b2 1504.90377 560.8316F t1 1.08208 0.01827F t2 0.87648 0.00408

Figure S13. (a) Virial fitting (lines) of the CO2 adsorption isotherms (points) of 2' measured at 298 (black), 313 (red) and 328

K (blue). (b-d) Dual-site Langmuir-Freundlich fitting (lines) of the CO2 adsorption isotherms (points) of 2' measured at 298


0.0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5 5.0 5.50

20

40

60

80

100

120 Virial method for 1 DSLF method for 1 Virial method for 1' DSLF method for 1'

Qst (

kJ m

ol-1

)

(a)

n (mmol g-1)

0.0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5 5.0 5.50

20

40

60

80

100

120 Virial method for 2 DSLF method for 2 Virial method for 2' DSLF method for 2'

Qst (k

J mol

-1)

(b)

n (mmol g-1)

Figure S14. Comparison of the coverage-dependent CO2 adsorption enthalpy obtained by the Virial and DSLF methods.

4000 3500 3000 2500 1280 1200 1120 1040

υ (O-H)

O O

OH

Desorption, He

guest-free, He

0.10 bar CO2

Wavenumber (cm-1)

υ (O-H)CO2, sym. str.

O O

OH

O O

OH

COH bend

0.15 bar CO2

Figure S15. In situ IR spectra of 2' with varied atmosphere measured at 313 K.

0.0 0.2 0.4 0.6 0.8 1.0

0.00

0.05

0.10

0.15

0.20

0.25

0.30 1 1 2 2 1' 1' 2' 2'

Gas

Upt

ake

(mm

ol g

-1)

Pressure (bar) Figure S16. N2 sorption isotherms of 1, 2, 1', and 2' measured at 298 K.

0 50 100 150 200 250 300 350 400

0

5

10

15

Mas

s Cha

nge

(%)

Time (min)

(a)

310

320

330

340

350

360

Tem

pera

ture

(K)

N2

CO2/N2 (15:85, v/v)

0 5 10 15 20

315

330

345

360

375

390

Hea

t Flo

w (W

g-1)

Tem

para

ture

(K)

Time (min)

(b)

-0.3

-0.2

-0.1

0.0

0.1

Figure S17. Repeated adsorption–desorption kinetics for 1' between a 15:85 CO2/N2 (v/v) flow at 313 K and a pure N2 flow at

358 K. (b) Heat flows from 2', as determined via DSC.

0 10 20 30 40 50 60 70 800.0

0.2

0.4

0.6

0.8

1.0

1.2

CO2

Co/C

i

Breakthrough time of 2 (min)

(a)

N2

0 100 200 300 400 500 600

0.0

0.2

0.4

0.6

0.8

1.0

1.2

Ci/C

o

Breakthrough time of 2' (min)

(b)

N2

CO2

0 10 20 30 40 50 60 700.0

0.2

0.4

0.6

0.8

1.0

1.2H2O

Breakthrough time of 2 (min)

Ci/C

o

(c)

N2CO2

0 60 120 180 240 300 360 420 480 540 600

0.0

0.2

0.4

0.6

0.8

1.0

1.2 H2O

N2 CO2

Ci/C

o

Breakthrough time of 2' (min)

(d)

Figure S19. Breakthrough curves of Fig. 4 expressed using time (min) as abscissa.

0 10 20 30 40 50 600.0

0.2

0.4

0.6

0.8

1.0

1.2

CO2

Co/C

i

Specific breakthrough time of 2 (min g-1)

(a)

N2

0 60 120 180 240 300 360

0.0

0.2

0.4

0.6

0.8

1.0

1.2

Ci/C

o

Specific breakthrough time of 2' (min g-1)

(b)

N2

CO2

0 10 20 30 40 500.0

0.2

0.4

0.6

0.8

1.0

1.2H2O

Specific breakthrough time of 2 (min g-1)

Ci/C

o

(c)

N2 CO2

0 60 120 180 240 300 360

0.0

0.2

0.4

0.6

0.8

1.0

1.2H2O

N2CO2

Ci/C

o

Specific breakthrough time of 2' (min g-1)

(d)

Figure S20. Breakthrough curves of Fig. 4 expressed using specific breakthrough time (min g-1) as abscissa.

Table S1. Comparison of the best CO2 adsorption performances of PCPs. Note: the highest values of each parameter were

highlighted in boldface.

CO2 uptake at 298 K and 1 atm Compound

(common name) Qst

(kJ/mol) Dc

(g cm-3) mmol g−1 mmol cm−3

Selectivitya

(298 K) Type of

active sitesi Ref

[Mn2Cl2(bbta)] 38g/43b 1.074 5.36 5.76 26 OMS This work [Co2Cl2(bbta)] 28g/33b 1.138 4.24 4.82 24 OMS This work

[Mn2Cl2(bbta)(OH)] 99g/120b 1.227 7.14 8.76 250 OMS+LBS This work [Co2Cl2(bbta)(OH)] 110g/124b 1.354 6.70 9.07 262 OMS+LBS This work

CD-MOF-2 113.5h 0.996 2.59 2.58 NA LBS S1 en-Mg2(dobpdc) 51b 0.955 4.57 4.36 230 OMS+LBS S2

mmen-Mg2(dobpdc) 71b 1.073 3.86 4.14 200 OMS+LBS S3 mmen-CuBTTri 66g/96f 1.059 4.2 4.45 165 OMS+LBS S4 SIFSIX-2-Cu-i 31.9 1.246 5.41 6.74 183 LBS S5

CAU-1 48c 0.892 3.8 3.39 45#4 LBS S6 Mg2(dobdc) 47d 0.920 8.04#1 7.40#1 44#3 OMS S7

MAF-35 47b, e 1.357 4.46 6.05 37 OMS S8 bio-MOF-11 45c 1.234 5.0 6.17 65 LBS S9 rht-MOF-7 45f 0.783 4.76 3.73 NA OMS+LBS S10

Mg2(dobpdc) 44b 0.713 6.42 4.58 NA OMS S3 Cu-TDPAT 42g 0.782 7.94 6.21 36 OMS+LBS S11 Ni2(dobdc) 41c 1.194 5.8#1 6.93#1 30 OMS S7

Zn2(ox)(atz) 41e 1.713 3.79#2 6.50#2 NA LBS S12 Co2(dobdc) 37d 1.177 6.96#1 8.20#1 NA OMS S7 HKUST-1 35e 0.879 4.86 4.27 101#2 OMS S13

[Cu(Me-4py-trz-ia)] 30d 0.928 6.1#1 5.7 NA OMS+LBS S14 PCN-88 27g 0.657 5.5 3.64#1 60 OMS S15 MAF-66 26g 1.128 5.0 5.6 185 LBS S16

Cu-TPBTM 26g 0.627 4.72 2.96 20 OMS+LBS S17 PEI (40 wt%)⊂

PAF-5 68.7b NA 3.6 NA 1200 LBS S18

PEI-MIL-101-100 NA NA 5.00 NA 770 LBS S19

mmen = N,N'-dimethylethylenediamine; BTTri = 1,3,5-tris(1H-1,2,3,-triazol-5-yl)benzene; dobpdc = 4,4'-dioxido-3,3'-biphenyldicarboxylate; dobdc = 2,5-dioxido-1,4-benzenedicarboxylate; TDPAT = 2,4,6-tris(3,5-dicarboxylphenyl-amino)-1,3,5-triazine; ox = oxalate; atz = 3-amino- 1,2,4-triazole; Me-4py-trz-ia = 5-(3-methyl-5-(pyridine-4-yl)-(4H-1,2,4-triazol-4-yl)isophthalate); TPBTM = N,N',N''-tris(isophthalyl)-1,3,5-benzenetricarboxamide. SIFSIX = SiF6

2- anions; PEI = polyethyleneimine. a The CO2/N2 selectivity can be calculated by several methods. To compared the practical performances of different materials, the CO2/N2 selectivity discussed in this work is calculated under the flue gas condition, which is equal to uptake ratio at the partial pressures of each gas devided by the pressure ratio. b Obtained by the Clausius−Clapeyron equation and dual-site Langmuir−Freundlich fitting. c Obtained by the Clausius−Clapeyron equation and single-site Langmuir−Freundlich fitting. d Obtained by the Clausius−Clapeyron equation and Toth fitting. e Obtained by the Clausius−Clapeyron equation without mathematical fitting. f Obtained by the Clausius−Clapeyron equation and dual-site Langmuir fitting. g Obtained by the Virial fitting method. h Obtained by calorimetric methodology. #1 296 K; #2 293 K; #3 303 K; #4273 K. i LBS = Lewis basic site.

Table S2. Summary of the Crystal Data and Structure Refinement results.

Compound 1 1' 2 2' Formula C6H2Cl2Mn2N6 C6H3Cl2Mn2N6O C6H2Cl2Co2N6 C6H3Cl2Co2N6O

Formula weight 338.92 355.91 346.89 363.90

Temperature (K) 293(2) 293(2) 293(2) 293(2) Space group R-3m R-3m R-3m R-3m

a (Å) 25.40(3) 24.58(1) 24.44(3) 24.28(4) c (Å) 8.542(8) 8.318(4) 8.088(10) 7.867(14)

V (Å3 ) 4773(14) 4352(5) 4182(13) 4016(17) Z 18 18 18 18

Dc (g cm-3) 1.061 1.226 1.138 1.354 μ (mm-1) 1.430 1.588 2.058 2.151 Rp (%) 1.96 0.98 0.75 0.58 Rwp (%) 2.66 1.72 1.14 0.81

M1-N1 (Å) 2.232(3) 2.088(2) 2.123(2) 2.086(2) M1-N2 (Å) 2.167(2) 2.104(2) 2.068(2) 2.011(2) M1-Cl1 (Å) 2.420(2) 2.371(3) 2.317(5) 2.294(2) M1-O1 (Å) NA 1.999(2) (MnIII-OH) NA 1.972(6) (CoIII-OH)void (%)a 59.8 54.0 57.4 53.6

pore volume (cm3 g-1) b 0.56 0.44 0.50 0.40 R

p = Σ|cY

sim(2θ

i) − I

exp(2θ

i) + Y

back(2θ

i)|/Σ|I

exp (2θ

i)|.

Rwp

= {wp[cY

sim(2θ

i) − I

exp(2θ

i) + Y

back(2θ

i)]

2/Σw

p [I

exp(2θ

i)]

2}

1/2, and w

p = 1/I

exp(2θ

i).

R1 = ∑||Fo| - |Fc||/∑|Fo|. wR2 = [∑w(Fo2 - Fc

2)2/∑w(Fo2)2]1/2.

a Calculated by the SOLV routine in Platon (Version: 131110).[A. Spek, J. Appl. Crystallogr. 2003, 36, 7]

b Pore volume = void / Dc.

Table S3 Elemental analyses.

C/N ratio Carbon, % Nitrogen, % Hydrogen, % Sample

Exp. Calc. Exp. Calc. Exp. Calc. Exp. Calc.

[Mn2(H2O)2Cl2(bbta)]·6.5H2O

(C6H19Cl2Mn2N6O8.5) (1) 0.887 0.857 14.97 14.65 16.87 17.08 3.91 3.89

[Mn2(OH)(H2O)Cl2(bbta)]·6.5H2O

(C6H18Cl2Mn2N6O8.5) (1') 0.887 0.857 15.00 14.68 16.91 17.11 3.88 3.69

[Co2(H2O)2Cl2(bbta)]·6H2O

(C6H18Cl2Co2N6O8) (2) 0.863 0.857 14.97 14.68 17.35 17.12 3.67 3.70

[Co2(OH)(H2O)Cl2(bbta)]·5.5H2O

(C6H16Cl2Co2N6O7.5) (2') 0.864 0.857 15.17 14.98 17.56 17.47 3.351 3.353

[Mn2(HCO3)(H2O)Cl2(bbta)]·1.7H2O

(C7H9.2Cl2Mn2N6O6.1) (1'·CO2) 1.000 1.000 18.74 18.45 18.73 18.45 2.356 2.035

[Mn2(OH)(H2O)Cl2(bbta)]·6.5H2O*

(C6H18Cl2Mn2N6O8.5) (1') 0.887 0.857 15.05 14.68 16.97 17.11 3.869 3.69

[Co2(HCO3)(H2O)Cl2(bbta)]·1.8H2O

(C7H8.6Cl2Co2N6O5.8) (2'·CO2) 1.000 1.000 18.34 18.56 18.33 18.55 2.052 1.891

[Co2(OH)(H2O)Cl2(bbta)]·5.5H2O*

(C6H16Cl2Co2N6O7.5) (2') 0.865 0.857 15.18 14.98 17.55 17.47 3.351 3.353

*The sample was obtained by heating the corresponding CO2-captured sample under high vacuum at 85 oC for 2 h.

Table S4. Comparing the performances of capturing CO2 from simulated flue gas (T = 313 K, PCO2 = 0.15 bar) of 1' and 2'

with the highest reported values.

Compound Density

(g cm-3)

Gravimetric

capacity

(wt %)

Volumetric

capacity

(mmol cm-3)

Regeneration

condition Qst

(kJ/mol) Ref

mmen-Mg2(dobpdc) 1.073 11.1 2.5 N2 purge at 393 K 71 S3

en-Mg2(dobpdc) 0.955 14.6 3.2 Ar purge at 423 K 51 S2

1' 1.227 13.1 3.7 N2 purge at 358 K 124 This work

2' 1.354 13.4 4.1 N2 purge at 358 K 120 This work

References

(S1) D. Wu, J. J. Gassensmith, D. Gouvêa, S. Ushakov, J. F. Stoddart, A. Navrotsky, J. Am. Chem. Soc. 2013, 135, 6790.

(S2) W. R. Lee, S. Y. Hwang, D. W. Ryu, K. S. Lim, S. S. Han, D. Moon, J. Choi, C. S. Hong, Energy Environ. Sci. 2014, 7,

744.

(S3) T. M. McDonald, W. R. Lee, J. A. Mason, B. M. Wiers, C. S. Hong, J. R. Long, J. Am. Chem. Soc. 2012, 134, 7056.

(S4) T. M. McDonald, D. M. D'Alessandro, R. Krishna, J. R. Long, Chem. Sci. 2011, 2, 2022.

(S5) P. Nugent, Y. Belmabkhout, S. D. Burd, A. J. Cairns, R. Luebke, K. Forrest, T. Pham, S. Ma, B. Space, L. Wojtas, M.

Eddaoudi, M. J. Zaworotko, Nature 2013, 495, 80.

(S6) X. Si, C. Jiao, F. Li, J. Zhang, S. Wang, S. Liu, Z. Li, L. Sun, F. Xu, Z. Gabelica, C. Schick, Energy Environ. Sci. 2011, 4,

4522.

(S7) S. R. Caskey, A. G. Wong-Foy, A. J. Matzger, J. Am. Chem. Soc. 2008, 130, 10870.

(S8) D.-D. Zhou, C.-T. He, P.-Q. Liao, W. Xue, W.-X. Zhang, H.-L. Zhou, J.-P. Zhang, X.-M. Chen, Chem. Commun. 2013,

49, 11728.

(S9) J. An, S. J. Geib and N. L. Rosi, J. Am. Chem. Soc., 2009, 132, 38;

(S10) R. Luebke, J. F. Eubank, A. J. Cairns, Y. Belmabkhout, L. Wojtas, M. Eddaoudi, Chem. Commun. 2012, 48, 1455.

(S11) B. Li, Z. Zhang, Y. Li, K. Yao, Y. Zhu, Z. Deng, F. Yang, X. Zhou, G. Li, H. Wu, N. Nijem, Y. J. Chabal, Z. Lai, Y.

Han, Z. Shi, S. Feng and J. Li, Angew. Chem., Int. Ed., 2012, 51, 1412.

(S12) R. Vaidhyanathan, S. S. Iremonger, K. W. Dawson and G. K. Shimizu, Chem. Commun., 2009, 5230.

(S13) Q. Min Wang, D. Shen, M. Bülow, M. Ling Lau, S. Deng, F. R. Fitch, N. O. Lemcoff, J. Semanscin, Microporous and

Mesoporous Mater. 2002, 55, 217.

(S14) D. Lassig, J. Lincke, J. Moellmer, C. Reichenbach, A. Moeller, R. Glaser, G. Kalies, K. A. Cychosz, M. Thommes, R.

Staudt, H. Krautscheid, Angew. Chem., Int. Ed. 2011, 50, 10344.

(S15) J. R. Li, J. Yu, W. Lu, L. B. Sun, J. Sculley, P. B. Balbuena and H. C. Zhou, Nat. Commun., 2013, 4, 1538.

(S16) R. B. Lin, D. Chen, Y. Y. Lin, J. P. Zhang and X. M. Chen, Inorg. Chem., 2012, 51, 9950.

(S16) R. B. Lin, D. Chen, Y. Y. Lin, J. P. Zhang and X. M. Chen, Inorg. Chem., 2012, 51, 9950.

(S17) B. Zheng, J. Bai, J. Duan, L. Wojtas and M. J. Zaworotko, J. Am. Chem. Soc., 2011, 133, 748.

(S18) S. Y. Sung and M. P. Suh, J. Mater. Chem. A, 2014, 2, 13245.

(S19) Y. C. Lin, Q. J. Yan, C. L. Kong and L. Chen, Sci. Rep. 2013, 3, 1859.

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