Exceptional Adsorption and Binding of Sulfur Dioxide in a Robust Zirconium-Based Metal-Organic Framework

Article abstract of DOI:10.1021/jacs.8b08433

We report a record-high SO₂ adsorption capacity of 12.3 mmol g^-1 in a robust porous material, MFM-601, at 298 K and 1.0 bar. SO₂ adsorption in MFM-601 is fully reversible and highly selective over CO₂ and N

Full text of DOI:10.1021/jacs.8b08433

Communication
Cite This: J. Am. Chem. Soc. XXXX, XXX, XXX−XXX
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Exceptional Adsorption and Binding of Sulfur Dioxide in a Robust
Zirconium-Based Metal−Organic Framework
†
,‡
†
†
§
†
†
Joseph H. Carter, Xue Han, Florian Y. Moreau, Ivan da Silva, Adam Nevin, Harry G. W. Godfrey,
‡
,†
,†
Chiu C. Tang, Sihai Yang,* and Martin Schroder*
̈
†
‡
§
School of Chemistry, University of Manchester, Manchester M13 9PL, United Kingdom
Diamond Light Source, Harwell Science Campus, Oxfordshire OX11 0DE, United Kingdom
ISIS Facility, STFC Rutherford Appleton Laboratory, Oxfordshire OX11 0QX, United Kingdom
*
S Supporting Information
MFM-600. This is accompanied by significant enhancement of
gas adsorption in MFM-601, notably simultaneous increases in
SO2 uptake (146%) and selectivity over CO2 and N2.
ABSTRACT: We report a record-high SO adsorption
2
capacity of 12.3 mmol g− in a robust porous material,
1
MFM-601, at 298 K and 1.0 bar. SO adsorption in MFM-
2
Significantly, MFM-601 shows a SO adsorption capacity of
2
−
1
6
01 is fully reversible and highly selective over CO and
2
12.3 mmol g at 298 K and 1.0 bar, representing the highest
value observed to date in porous materials under the same
conditions. In addition, the binding domains for adsorbed CO2
and SO2 in MFM-610 have been determined by in situ
synchrotron X-ray diffraction.
N . The binding domains for adsorbed SO and CO
2
2
2
molecules in MFM-601 have been determined by in situ
synchrotron X-ray diffraction experiments, giving insights
at the molecular level to the basis of the observed high
selectivity.
4
,4′,4″,4′′′-(1,4-Phenylenebis(pyridine-4,2,6-triyl))tetra
benzoic acid (H L, Scheme 1) was prepared via a three-step
4
he International Energy Outlook 2017 report produced
by the U.S. Energy Information Administration predicts
Scheme 1. Synthesis of MFM-601 from 4,4′,4″,4′′′-(1,4-
T
Phenylenebis(pyridine-4,2,6-triyl))tetrabenzoic Acid (H L)
4
that fossil fuels will account for ∼77% of global energy
production in 2050, with coal comprising a major component
1
of the overall energy supply. The burning of bituminous, sub-
bituminous and lignite coals produces SO at a concentration
2
of between 500 and 3000 ppm, around 95% of which is
removed via limestone-scrubbing or the wet-sulfuric-acid
2
processes. Although these processes are effective, as much
as 400 ppm of SO can remain in the exhaust gas, which, when
2
synthesis (Scheme S1). [Zn (μ -O) (μ -OH) (OH) (L) -
6
3
4
3
4
4
2
vented to the atmosphere, poses significant health risks and
(
H L) ] (MFM-600) was synthesized by heating a mixture
4 0.7
3
environmental impact. Small amounts of SO in flue gas can
2
of ZrCl , H L and benzoic acid as modulator in DMF at 120
4 4
also react with organo-amines used for CO -scrubbing causing
2
°C for 24 h and was isolated as plate-shaped colorless single
4
permanent loss of activity. Physisorption of SO by porous
materials such as zeolites, mesoporous silica, ionic microgels
and activated carbons using supramolecular host−guest
interactions is a promising approach that can give high
selectivity, reversibility and low energy penalty for system
regeneration. However, these materials generally suffer from
2
crystals. The single crystal X-ray structure shows that MFM-
5
6
7
8
+
6
00 contains [Zr (μ -O) (μ -OH) (OH) ] clusters, first
6 3 4 3 4 4
12
8
IV
observed in UiO-66. In this cluster the six Zr ions form
an octahedron with the 8 faces each capped by a μ -O or μ -
3
3
4
−
OH. Eight of the edges of the octahedron are bridged by L
linkers via bidentate carboxylate groups with the remaining
low adsorption capacities and exposure to SO often leads to
irreversible structural degradation.
four equatorial edges each bridged by a H L linker (occ =
2
4
0.35) that is monodentate to each equatorial Zr(IV) center
and bound through the CO moiety of the carboxylate
groups (Figure S4). The coordination sphere at the equatorial
Metal−organic frameworks (MOFs) are emerging porous
9
materials constructed from metal clusters with organic linkers,
−
and their tuneability makes them interesting candidates for
Zr(IV) centers is completed by a terminal OH ligand.
1
0
many applications. Although much work has focused on the
MFM-600 was treated with an 8 M solution of HCl, which
led to a structural phase transition to MFM-601, [Zn (μ -
study of gas separations in MOFs, very little effort has been
6
3
11
O) (μ -OH) (OH) (H O) (L) ], the structure of which was
devoted to the sequestration of SO2, since it often leads to
severe structural degradation of the material and/or irreversible
uptake. Here, we report the exceptional adsorption and
4
3
4
4
2
4
2
determined by high resolution synchrotron powder X-ray
diffraction with the {Zr } node assigned to the MIX-staggered
6
reversible binding of SO in two Zr-based MOFs, MFM-600
2
and MFM-601. MFM-601 is obtained by postsynthetic
removal of a linker in an ordered, predictable pattern from
Received: August 7, 2018
©
XXXX American Chemical Society
A
DOI: 10.1021/jacs.8b08433
J. Am. Chem. Soc. XXXX, XXX, XXX−XXX

Journal of the American Chemical Society
Communication
1
3
proton topology. In MFM-601, the H L monodentate linkers
4
from the equatorial positions of the {Zr } cluster have been
6
removed (Figure 1) and replaced with terminal H O
2
Figure 1. Views of (a) disordered H L linker present in MFM-600;
4
−
(
{
b) “fully bound” L4 linker present in MFM-600 and MFM-601; (c)
6
Zr } node present in MFM-600 and MFM-601; (d) structure of
MFM-600; (e) structure of MFM-601.
Figure 2. (a) SO sorption isotherms in MFM-600 and MFM-601.
2
(
b) Comparison of SO , CO and N isotherms at 298 K in MFM-
2 2 2
molecules. As a result, the alternating linkage between the
6
01. (c) Q values for SO , CO and N in MFM-600 and MFM-601.
st 2 2 2
8+
4−
[
Zr (μ -O) (μ -OH) (OH) (H O) ] cluster and the L
6 3 4 3 4 4 2 4
(d) IAST selectivities of SO /CO and SO /N at 298 K in MFM-600
2 2 2 2
linker yields two types of channels of ∼9 Å (cylinder-shaped)
and ∼12 Å (waterdrop-shaped) diameter running through the
structure of MFM-601 along the c-axis. This leads to an
and MFM-601 as a function of substrate ratios.
2
−1
increase in the BET surface area from 2281 m g for MFM-
601 exhibits a type V isotherm with slow initial uptake at low
pressures before the uptake increases more rapidly at
intermediate pressures reaching a plateau at ∼24 mmol g
at 30 bar and 298 K (Figure S15). Adsorption of N in MFM-
2
−1
6
00 to 3644 m g for MFM-601, a rise of ∼60%. We note that
−
1
MFM-601 has recently been reported (as BUT-15) as an
III
14
adsorbent for Fe ions in water. Acid treatment has been
previously reported as an efficient approach to remove free
ligands such as surplus benzoic acid modulator in Zr-based
MOFs and as a method of improving the N uptake in UiO-
6.
Sorption isotherms of SO , CO and N were measured on
2
601 follows a type-I isotherm with a total uptake of ∼12 mmol
−
1
g
at 80 bar 298 K. Strikingly, despite the high uptake of SO
2
1
5
at 298 K and 1.0 bar, under the same conditions the CO2
uptake in MFM-601 compares poorly to other MOFs in the
2
16
6
19
−1
literature, with a total CO uptake of only 1.3 mmol g and
2
2
2
2
desolvated samples. As expected, the higher BET surface area
of MFM-601 allows a greater total uptake of all three gases.
a negligible N uptake. The isosteric heat of adsorption (Q )
2
st
for SO , CO and N2 in MFM-600 and MFM-601 are
2
2
MFM-600 displays a two-step Type-IV isotherm for SO with
compared in Figure 2c. The same trend is followed for both
2
an excess uptake of 5.0 mmol g− at 298 K and 1.0 bar.
1
MOFs with N having the lowest Q , followed by CO and
2
st
2
Interestingly, in comparison, MFM-601 exhibits a type-I
then SO with the highest Q . Interestingly the Q values for
2
st
st
isotherm for SO leading to an exceptionally high uptake of
SO in MFM-600 are generally higher than in MFM-601,
2
2
−
1
1
2.3 mmol g (146% enhancement) at 298 K and 1.0 bar,
consistent with the smaller cages of MFM-600 affording
representing the highest value observed in porous solids and
greater overlap potentials between SO molecules and the pore
2
notably higher than a range of best-behaving SO sorbents
interior. In MFM-600 at low loadings SO interacts with
2
2
(
Table S1). Importantly, no loss of adsorption capacity of SO2
binding sites at the MOF surface. As these sites become less
was observed in MFM-601 over five cycles of adsorption/
available Q reduces, but once SO fills the pore, SO −SO
st
2
2
2
desorption (Figure S17b). The SO uptake in MFM-601 is
dipole interactions lead to an increase in Q .
2
st
further increased to 16.9 mmol g− at 273 K and 1.0 bar
1
Analysis of adsorption selectivities at 298 K using ideal
adsorbed solution theory (IAST) shows that the
transformation of MFM-600 to MFM-601 is accompanied by
an increase in selectivity of SO over both CO and N (Figure
(Figure S17a). MFM-601 shows fully reversible adsorption of
SO at both 273 and 298 K, allowing the total evacuation of
2
the framework upon desorption under pressure-swing con-
ditions (Figure 2) with no structural phase change or
framework collapse, as evidenced by the postsorption PXRD
patterns (Figure S8). This is in contrast to the current leading
2
2
2
2). The selectivity for equimolar mixtures of SO /CO and
2
2
SO /N in MFM-601 at 298 K are 32 and 255, respectively,
2
2
20
comparable with the leading MOFs in the literature. The
SO sorbent, MFM-202a, which undergoes irreversible phase
capability of selective separation of SO from gas mixtures
2
2
17
change to MFM-202b upon SO adsorption, and Ni(bdc)-
using fixed-bed packed with MFM-601 has been confirmed by
dynamic breakthrough experiments (Figure 3 and SI).
In order to examine the origins of the preferential adsorption
of SO over CO in MFM-601, in situ synchrotron X-ray
2
(
ted)0.5 and MOF-74(Mg), which release up to 40% of the
18
captured SO upon desorption. The desorption of SO from
SIFSIX-1-Cu has not been reported. Interestingly, the high
2
2
20a
2
2
uptake of SO in MFM-601 does not correlate with equivalent
powder diffraction studies were carried out (Figures 4 and 5).
2
increases in uptake of CO or N . The uptake of CO in MFM-
Rietveld refinement of PXRD data for CO -loaded MFM-601
2
2
2
2
B
DOI: 10.1021/jacs.8b08433
J. Am. Chem. Soc. XXXX, XXX, XXX−XXX

Journal of the American Chemical Society
Communication
0
.38) and CO2VI (occupancy = 0.16) occupy similar environ-
ments either side of the zirconium cluster in that they are both
in close proximity to the terminal hydroxyl [(OCO2···O =
2
.58(23) Å) and [OCO2···O = 3.31(44) Å], respectively, as well
as the μ -O [(O ···μ -O = 2.20(10) Å) and [O ···μ -O =
3
CO2
3
CO2
3
III
V
3
.37(14) Å], respectively. The remaining sites, CO
2
IV
(
(
{
occupancy = 0.33), CO2 (occupancy = 0.30) and CO2
occupancy = 0.17), are not within binding distance of the
Zr } cluster but are closer to the L linker. CO2 is near the
4−
III
6
phenyl ring of the linker [OCO2···Ph = 2.79(8) Å] whereas
IV
V
CO2 and CO2 are close to the pyridyl rings [OCO2···NPyr
=
4
.38(5) Å)] and [OCO2···HPyr = 3.91(25) Å], respectively. All
Figure 3. Breakthrough curves of 2500 ppm of SO diluted in (a) 1:1
2
CO sites are within intermolecular binding distance of one
He:N and (b) 1:1 He:CO through a fixed-bed packed with MFM-
2
2
2
6
01 at 298 K and 1 bar.
another with C···O distances between 2.18(14) and 4.38(12)
Å. However, no ordered CO molecule was present at the
2
center of the large pore of MFM-601, thus confirming that
CO positioning is dominated by host−guest interactions.
2
The crystal structure of SO -loaded MFM-601 at 298 K also
2
shows six binding sites within the pore giving a formula of
[
Zr (μ -O) (μ -OH) (OH) (H O) (L) ][SO ] . The three
6 3 4 3 4 4 2 4 2 2 10.71
I
SO positions with the highest occupancies, SO (occupancy =
1
2
2
II
III
.00), SO2 (occupancy = 0.87) and SO2 (occupancy = 0.63)
form an intermolecular dipole bonding network with S···O
bond distances between 3.59(7) and 3.24(6) Å, thus exhibiting
efficient packing as exhibited by the similarity to the
22
intermolecular distances observed in solid SO . The highest
2
I
2
occupied SO position (SO ) is located near the terminal
2
hydroxyl of the {Zr } cluster [OSO2···O = 2.53(6) Å] with a
6
similar SO -hydroxyl interaction to that observed in MFM-
2
2
0b
II
3
00(In). SO2 sits away from the zirconium cluster, close to
4
−
the pyridyl group of the L linker [OSO2···Pyr = 3.06(6) Å].
III
Conversely, SO2 is not in close proximity to the pore wall
Figure 4. View of SO (top) and CO (bottom) in MFM-601; the
size of the colored balls represent the occupancy at each site. Positions
refined by in situ synchrotron PXRD.
2
2
and is only within interaction distance of other SO molecules.
SO2 (occupancy = 0.46) occupies a position between two
phenyl rings of two opposite linkers related by a mirror plane.
2
IV
It is in close proximity to both the terminal hydroxyl [OSO2···O
=
1.99(10) Å] and the μ -O [S ···μ -O = 3.42(5) Å] of the
3 SO2 3
8+ IV
[Zr (μ -O) (μ -OH) (OH) (H O) ] cluster. As for SO2 ,
6 3 4 3 4 4 2 4
V
SO2 (occupancy = 0.31) resides in between the phenyl rings
of two opposite L linkers and also is in close proximity to the
4
−
terminal hydroxyl [OSO2···O = 3.48(15) Å] and the μ -O
3
[
OSO2···μ -O = 3.06(15) Å] of the {Zr } cluster. The least
3 6
VI
occupied SO site (SO ; occupancy = 0.31) lies near to a
2
2
pyridyl ring of the organic linker [OSO2···HPyr = 2.75(19)Å]
and also exhibits the potential for dipole−dipole interaction
V
VI
V
with SO [O ···S = 3.53(18)Å] (Figures 4 and 5).
2
In conclusion, exceptional adsorption of SO and selective
2
Figure 5. Binding sites of SO (top) and CO (bottom) in MFM-601.
2
2
sorption of SO over CO and N have been demonstrated in a
2
2
2
robust Zr-based MOF, MFM-601. By locating the positions of
CO and SO in MFM-601, key understanding of the observed
uptake and selectivity has been gained. It has been shown that
at 200 K revealed six binding sites within the pores, giving a
2
2
formula of [Zr (μ -O) (μ -OH) (OH) (L) ][CO ] . The
6
3
4
3
4
4
2
2 5.52
I
the dipole moment of SO can be utilized by MFM-601 not
primary binding site of CO in MFM-601 (occupancy = 0.50)
2
2
only to provide stable binding within the pores but also to
overlaps with the terminal oxygen of the zirconium cluster due
to the removal of four H O molecules from each {Zr } cluster
drive intermolecular interactions between SO molecules.
2
2
6
upon activation, leaving a terminal hydroxyl and an open
zirconium site on each of the four equatorial edges of the
ASSOCIATED CONTENT
Supporting Information
The Supporting Information is available free of charge on the
ACS Publications website at DOI: 10.1021/jacs.8b08433.
■
8+
[
Zr (μ -O) (μ -OH) (OH) ] cluster, thus accounting for
*
S
6
3
4
3
4
4
I
the 0.5 occupancy of the terminal oxygen and CO . This
2
I
positioning of CO puts it within close proximity to the open
2
zirconium site [OCO2···Zr = 2.40(10) Å] as well as being within
binding distance of the terminal hydroxyl [CCO2···O= 2.00(24)
Å] and the μ -O of the Zr O cluster [C ···μ -O= 2.70(11)
Data for (C475.2H248N21.6O139.2Zr ) (CIF)
24
Data for C H N O Zr (CIF)
4
4
24
2
16
3
3
6
8
CO2
3
21
II
Å], similar to that observed in UiO-66. CO2 (occupancy =
Data for C44
H
N
24
O
2
14Zr
3
, 7.36(CO ) (CIF)
2
C
DOI: 10.1021/jacs.8b08433
J. Am. Chem. Soc. XXXX, XXX, XXX−XXX

Journal of the American Chemical Society
Communication
(
15) Wang, T. C.; Vermeulen, N. A.; Kim, I. S.; Martinson, A. B. F.;
Data for C H N O Zr , 14.272(SO ) (CIF)
Synthesis, characterization, and analysis of crystal
structures (PDF)
4
4
24
2
16
3
2
Stoddart, J. F.; Hupp, J. T.; Farha, O. K. Nat. Protoc. 2016, 11, 149−
62.
16) Piscopo, C. G.; Polyzoidis, A.; Schwarzer, M.; Loebbecke, S.
1
(
Microporous Mesoporous Mater. 2015, 208, 30−35.
AUTHOR INFORMATION
Corresponding Authors
Sihai.Yang@manchester.ac.uk;
M.Schroder@manchester.ac.uk
(17) Yang, S.; Liu, L.; Sun, J.; Thomas, K. M.; Davies, A. J.; George,
■
M. W.; Blake, A. J.; Hill, A. H.; Fitch, A. N.; Tang, C. C.; Schro
J. Am. Chem. Soc. 2013, 135, 4954−4957.
18) Tan, K.; Canepa, P.; Gong, Q.; Liu, J.; Johnson, D. H.;
̈
der, M.
*
(
*
Dyevoich, A.; Thallapally, P. K.; Thonhauser, T.; Li, J.; Chabal, Y.
ORCID
Chem. Mater. 2013, 25, 4653−4662.
(
19) Trickett, C. A.; Helal, A.; Al-Maythalony, B. A.; Yamani, Z. H.;
Sihai Yang: 0000-0002-1111-9272
̈
Martin Schroder: 0000-0001-6992-0700
Notes
The authors declare no competing financial interest.
CCDC-1850112, 1854228, 1854229 and 1854234 contain the
supplementary crystallographic data.
Cordova, K. E.; Yaghi, O. M. Nat. Rev. Mater. 2017, 2, 17045.
(20) (a) Cui, X.; Yang, Q.; Yang, L.; Krishna, R.; Zhang, Z.; Bao, Z.;
Wu, H.; Ren, Q.; Zhou, W.; Chen, B.; Xing, H. Adv. Mater. 2017, 29,
1606929. (b) Savage, M.; Cheng, Y.; Easun, T. L.; Eyley, J. E.; Argent,
S. P.; Warren, M. R.; Lewis, W.; Murray, C.; Tang, C. C.; Frogley, M.
D.; Cinque, G.; Sun, J.; Rudic,
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ACKNOWLEDGMENTS
■
(
We thank EPSRC (EP/I011870), ERC (AdG 742041) and
University of Manchester for funding. We thank Diamond
Light Source for access to Beamline I11 and for awarding
J.H.C. a Ph.D. scholarship.
Chen, P.; Yildirim, T.; Zhou, W. J. Am. Chem. Soc. 2013, 135, 10525−
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DOI: 10.1021/jacs.8b08433
J. Am. Chem. Soc. XXXX, XXX, XXX−XXX