Diffusion Control in the in Situ Synthesis of Iconic Metal–Organic

Jan 3, 2018 - Ionic polymers that possess ion-exchangeable sites have been shown to be a greatly useful platform to fabricate mixed matrices (MMs) whe...
0 downloads 6 Views 7MB Size
Subscriber access provided by University of Florida | Smathers Libraries

Article

Diffusion-Control in the In Situ Synthesis of Iconic MetalOrganic Frameworks within an Ionic Polymer Matrix Jungho Lim, Eun Ji Lee, Jae Sun Choi, and Nak Cheon Jeong ACS Appl. Mater. Interfaces, Just Accepted Manuscript • DOI: 10.1021/acsami.7b17662 • Publication Date (Web): 03 Jan 2018 Downloaded from http://pubs.acs.org on January 3, 2018

Just Accepted “Just Accepted” manuscripts have been peer-reviewed and accepted for publication. They are posted online prior to technical editing, formatting for publication and author proofing. The American Chemical Society provides “Just Accepted” as a free service to the research community to expedite the dissemination of scientific material as soon as possible after acceptance. “Just Accepted” manuscripts appear in full in PDF format accompanied by an HTML abstract. “Just Accepted” manuscripts have been fully peer reviewed, but should not be considered the official version of record. They are accessible to all readers and citable by the Digital Object Identifier (DOI®). “Just Accepted” is an optional service offered to authors. Therefore, the “Just Accepted” Web site may not include all articles that will be published in the journal. After a manuscript is technically edited and formatted, it will be removed from the “Just Accepted” Web site and published as an ASAP article. Note that technical editing may introduce minor changes to the manuscript text and/or graphics which could affect content, and all legal disclaimers and ethical guidelines that apply to the journal pertain. ACS cannot be held responsible for errors or consequences arising from the use of information contained in these “Just Accepted” manuscripts.

ACS Applied Materials & Interfaces is published by the American Chemical Society. 1155 Sixteenth Street N.W., Washington, DC 20036 Published by American Chemical Society. Copyright © American Chemical Society. However, no copyright claim is made to original U.S. Government works, or works produced by employees of any Commonwealth realm Crown government in the course of their duties.

Page 1 of 19 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

ACS Applied Materials & Interfaces

Diffusion-Control in the In Situ Synthesis of Iconic Metal-Organic Frameworks within an Ionic Polymer Matrix Jungho Lim, Eun Ji Lee, Jae Sun Choi, and Nak Cheon Jeong* Department of Emerging Materials Science, DGIST, Daegu 42988, Korea

ABSTRACT: Ionic polymers that possess ion-exchangeable sites have been shown to be a greatly useful platform to fabricate mixed matrices (MMs) where metal-organic framework (MOFs) can be in situ synthesized, although the in situ synthesis of MOF has been rarely studied. In this study, alginate, an anionic green polymer that possesses metal ion-exchangeable sites, is employed as a platform of MMs for the in situ synthesis of iconic MOFs, HKUST-1 and MOF-74(Zn). We demonstrate for the first time that the sequential order of supplying MOF ingredients (metal ion and deprotonated ligand) into the alginate matrix leads to substantially different results due to a difference in the diffusion of the MOF components. For the examples examined, while the infusion of BTC3– ligand into Cu2+-exchanged ALG engendered the eggshell-shaped HKUST-1 layers on the surface of MM spheres, the infusion of Cu2+ ions into BTC3–-included alginate engendered high dispersivity and junction-contact of HKUST-1 crystals in the alginate matrix. This fundamental property has been exploited to fabricate a flexible MOF-containing mixed matrix membrane by co-incorporating poly(vinyl alcohol). Using two molecular dyes– methylene blue and rhodamine 6G, further, we show that this in situ strategy is suitable for fabricating an MOF-MM that exhibits size-selective molecular uptake.

KEYWORDS: mixed matrix membrane, metal ion diffusion, ligand diffusion, alginate, biocompatible polymer, ionic polymer, in situ synthesis of MOF

INTRODUCTION Extensive study over the past few decades has been focused on the synthesis and characterization of microporous materials.1-2

Metal-organic frameworks (MOFs), a highly crystalline subset of these

materials that are assembled by the multiple link of coordination bonds between inorganic nodes and multitopic organic ligands, have shown promise in a wide variety of applications such as chemical separation,3-5 molecule storage,6-11 drug delivery,12-14 heterogeneous catalysis,15-22 electrocatalysis,23-24 electronic conduction,25-30 sensing,29,31-33 ion conduction,33-37 and redox chemistry,38-39 among others.4041

A recently fueling interest in MOFs is the fabrication of MOFs in the form of mixed matrices (MMs) with environmentally friendly polymers in part because MOF–polymer MMs are a highly useful platform to utilize MOFs for potential applications involving molecular sorption,42 chemical separation,43-54 and chemical sensing,55 and in part because global demand for sustainability is rapidly increasing. However, given that post-fabricated MOF-MMs prepared by mixing pre-synthesized MOF ACS Paragon Plus Environment 1

ACS Applied Materials & Interfaces 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

Page 2 of 19

crystallites with a polymer have often been characterized by (i) inhomogeneous distribution of the MOF particles in polymer matrix and (ii) inferior junction-contact between MOF crystal and polymer matrix,42 an alternating method to resolve these negative factors must be developed. In situ synthesis of MOFs in polymer matrix can be a good alternating method to the conventional post-fabrication.42-43,53-55

In particular, use of ionic polymers that possess ion-

exchangeable sites can be greatly efficient in the in situ fabrication of MOF-MMs because homogenously distributed ion-exchange sites can be the sites for the nucleation and growth of MOF crystallites and thereby, the MOF growth at such sites can be well harmonized with polymer chains in the matrix, leading to high homogeneity in the distribution and surface-junction of MOF crystallites.42-45 Nevertheless, the use of such ionic polymer for the in situ synthesis of MOFs have been rarely studied.42-43 Alginic acid (H+ALG), a linear copolymer covalently linked with (1-4)-linked β-Dmannuronate (M) and its C-5 epimer α-L-guluronate (G) in random sequences (MG-blocks) or blocks (M-block and G-block), is a good example of an ionic polymer.56

The H+ALG contains carboxylic

acids, where alkali, alkali earth, or transition metal ions can be substituted by exchanging the carboxylic protons.

For instances, H+ALG can be readily transformed to sodium alginate (Na+ALG) via

exchanging the H+ with Na+ ions. Also, the homopolymeric linear Na+ALG chains can be cross-linked when the Na+ ions are replaced with divalent cations, such as Ca2+, Mg2+, Cu2+ and Zn2+.

In addition,

the alginates (the anionic form of H+ALG polymer; hereafter ALG) are often sorted as a green polymer because it is widely used in arts, food, medical, pharmaceutical, and chemical industries with e.g., face masks, moisture retainer, food supplements, dental and prosthetic impression, antacid, paint thickener, textile-substrate, fertilizer, and 3D printing materials.

Thus, the H+ALG (or Na+ALG) is a good

candidate hirable as an ionic polymer matrix for the in situ synthesis. Here, we report regarding the in situ synthesis of an MOF-MM within an ALG matrix. Although several MOFs that can be readily synthesized at room temperature should be suitable for this demonstration, we limited our studies to HKUST-1 and MOF-74(Zn) (hereafter HK and MOF74, ACS Paragon Plus Environment 2

Page 3 of 19 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

ACS Applied Materials & Interfaces

respectively).

(We chose a room temperature synthesis because at a temperature higher than 60 °C, an

ALG polymer is swelled and subsequently, it causes the serious leak of metal ions or ligands contained in the polymer matrix, leading to the bulk crystallization of MOF in solution.) We demonstrate for the first time that the sequential order of supplying ingredients for synthesizing such MOFs (e.g., Cu2+ ion and

1,3,5-benzenetricarboxylate

(BTC3−)

ligand

for

HK

and

Zn2+

and

2,5-dioxido-1,4-

benzenedicarboxylate (DOBDC4−) for MOF74) into the ALG matrix leads to substantially different results (see Figure 1).

For the examples examined, while the in situ synthesis performed by infusing

BTC3– ligand into Cu2+-exchanged alginate (Cu2+ALG) sphere (route A) resulted in eggshell-shaped HK-ALG (hereafter, we refer to this matrix as LD-HK-ALG to describe a ligand-diffusional HK-ALG), the in situ synthesis performed by infusing Cu2+ ions into BTC3–-included ALG sphere (route B)57 resulted in highly homogeneous HK-ALG sphere (hereafter, we refer to this matrix as MD-HK-ALG to describe a metal-diffusional HK-ALG).

Using two molecular dyes (methylene blue and rhodamine 6G

whose sizes are critically different when compared to the size of HKUST-1 window), we also demonstrate that the MD-HK-ALG exhibits a superior behavior than the eggshell-shaped LD-HK-ALG in size-exclusive molecular sorption that must be applicable to molecule separation.

Further, this in

situ strategy was exploited to fabricate a flexible MOF-polymer mixed matrix membrane (MMM).

RESULTS AND DISCUSSION HKUST-1, a MOF comprised of multiple links of paddlewheel-like (Cu2+)2 nodes and BTC3– ligand, is a good example of a MOF that is readily synthesized at room temperature when a Lewis base such as triethylamine (TEA) is fed to deprotonate H3BTC ligand. Na+ALG is also a good example of soft anionic polymer that can substitute its Na+ ion with other cations. On the basis of these two facts, we envisioned that the in situ synthesis of HKUST-1 in Na+ALG polymer could be a very suitable strategy to form a mixed matrix.

Further, we hypothesized that in the in situ synthesis, the sequential

order of supplying Cu2+ ion or BTC3– ligand, i.e., (i) route A: infusion of BTC3– ligand into Cu2+exchanged alginate (Cu2+ALG) or (ii) route B: infusion of Cu2+ ions into BTC3–-included Ca2+ACS Paragon Plus Environment 3

ACS Applied Materials & Interfaces 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

Page 4 of 19

exchanged alginate (Ca2+ALG),57 can lead to a substantial difference in forming MMs because the sizes of BTC3– ligand and Cu2+ ion are considerably different, and ALG is basically an anionic polymer that possesses negative charges in its backbone chains. (In route B, Ca2+ ion was used as a chemical reagent to solidify the polymer matrix by cross-linking the polymer chains prior to Cu2+ infusion.) To demonstrate this hypothesis, we examined these two routes.

For the route A, first, we prepared

turquoise blue Cu2+ALG spheres by exchanging Na+ ion with Cu2+ ion (see Figure 1 and 2). Specifically, aqueous Na+ALG solution was dropped into an aqueous Cu(NO3)2 solution by using a pipette.

During this ion-exchange reaction, the linear polymer chains of Na+ALG are cross-linked

together by the electrostatic interchain interaction of carboxylates in its backbone with divalent Cu2+ ion and simultaneously, the liquid drop of the polymer solution became a solid phase sphere. Then, the Cu2+ ions in the spheres were allowed to react with BTC3– ligands by immersing the spheres into the BTC3– solution at room temperature. Information.

See detailed procedure in the Section S1 of Supporting

For the route B, first, we prepared BTC3–-containing Ca2+ALG spheres by dropping a

mixed solution of BTC3– and Na+ALG into an aqueous Ca(NO3)2 solution.

During this process, the

Na+-to-Ca2+ exchange allows a Na+ALG solution drop to be solidified to a sphere, where the inclusion of BTC3– ligand in the polymer sphere is simultaneously proceeded.

The in situ synthesis of MD-HK-

ALG through route B was then achieved by immersing the BTC3–-containing Ca2+ALG spheres into an aqueous Cu(NO3)2 solution at room temperature.

All processes in both route A and B were time-

course monitored by using optical microscopy (OM), scanning electron microscopy (SEM), and powder X-ray diffraction (PXRD) techniques.

We also characterized the content of HKUST-1 in an MD-HK-

ALG and LD-HK-ALG, using thermogravimetric (TG) analysis (see Section S2 of Supporting Information). OM and SEM images in Figure 2 show that the ligand-diffusion in the route A led to the formation of HKUST-1 layers only on the external surface of the sphere with eggshell-shape, although the reaction was allowed for 1 h. By contrast, the metal-diffusion in the route B led to the formation of HKUST-1 crystallites even in the core region of the ALG polymer sphere with high probability, ACS Paragon Plus Environment 4

Page 5 of 19 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

ACS Applied Materials & Interfaces

although the reaction was allowed for only 5 min (see OM and SEM images in Figure 3).

X-ray

diffraction (XRD) patterns of LD-HK-ALG and MD-HK-ALG samples were obtained after crushing the sphere samples.

In terms of XRD patterns, LD-HK-ALG samples exhibited behavior that differed

from those of MD-HK-ALG samples (Figure 4).

While MD-HK-ALG samples show XRD patterns

that are similar as that of highly crystalline HKUST-1 powder sample, LD-HK-ALG samples show the patterns whose intensities are comparatively low and whose background are comparatively high, indicating that the negligible amount of HKUST-1 is only included in the matrices.

This result is

highly consistent with the result observed in TG analysis (see Section S2 in Supporting Information). We ascribe this difference to a difference in the diffusion rate of BTC3– molecule and Cu2+ ion in polymer matrix because their sizes and charges are definitely different.

More concretely, while the

size of BTC3– ligand is approximately 8.8 Å (Section S3 in Supporting Information), the effective ionic radius of Cu2+ ion is only approximately 0.87 Å.58-59

Also, the negatively charged ALG backbone

enables to disrupt or block the diffusion of anionic BTC3– ligands that must transport to the inner place of ALG matrix if HKSUT-1 crystallites should be formed in the place. More conceivable is that once HKUST-1 crystals are formed on the external surface of the sphere, the formed crystals can also disrupt the infusion of Cu2+ ion in route B and subsequently, the diffusion rate of the Cu2+ ion can be substantially lowered. During the time for the retardation of Cu2+ infusion, the inner-filled BTC3– ligands can be effused toward the external surface of the spheres.

This

speculation is strongly supported by the formation of small crystalline HKUST-1 domains on the external surface of the sphere, which sizes are much smaller than those of the crystals formed in the inner place of the sphere (see Figure 3).

In general, high concentration of ingredients leads to more

nucleation and subsequently smaller crystals.

On the basis of this fact, we ascribe the formation of

smaller crystals to the accumulation and subsequently increased concentration of Cu2+ and BTC3– components at the region of external surface of sphere, which was led by the retarded infusion of Cu2+ ions and progressed effusion of BTC3– molecules. shows a pattern that is similar as that of route B.

In terms of the small crystal formation, route A

However, the formation of eggshell-shaped sphere in

ACS Paragon Plus Environment 5

ACS Applied Materials & Interfaces 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

Page 6 of 19

the route A can be thought as a result led by an extremely limited diffusion of BTC3– ligands due to its greater size and negative charge. We also hypothesized that the metal-diffusional in situ synthesis (route B) can engender the high dispersivity and good surface-junction of MOF crystals because the growth of MOF can be harmonious with polymer matrix. To ascertain this hypothesis, we examined the results from SEM and energy-dispersive X-ray spectroscopic (EDS) elemental analysis with MD-HK-ALG samples.

The

analyses clearly support our demonstration of the aforementioned hypothesis (see Sections S4 and S5 in Supporting Information). MOF-MMs have been expected to be useful in molecular sorption. To test the feasibility of this application, we examined the sorption of two different molecular dyes, methylene blue (MB, λmax = 652 nm) and rhodamine 6G (R6G, λmax = 528 nm), by exposing them to LD-HK-ALG and MD-HKALG spheres (see Supporting Information, Section S1 and S7).

Then, we continuously monitored UV-

vis absorption spectra of the solutions every 5 min to quantify the amounts of dye absorbed in the spheres.

The sorption by Cu2+ALG and Ca2+ALG spheres were also examined for comparison (see

Supporting Information, Section S8). As expected, while an MD-HK-ALG strongly absorbed MB molecules, exhibiting gradual decrease of the absorbance at 652 nm upon exposure to the solution, an LD-HK-ALG absorbed the dye only slightly (see Figures 5a–c). As also expected, both MD-HK-ALG and LD-HK-ALG absorbed the negligible amount of R6G, whose size is much larger than the window size of HKUST-1 (see Figures 5d–f and Section S9 of Supporting Information).

Further, we tested the

selectivity of these MMs in the sorption of the dyes, using a mixed solution of MB and R6G whose sizes are critical when compared to the size of HKUST-1 window (while the size of HK window is 8.5 Å, the kinetic diameters of MB and R6G are 7.0 and 13.0 Å, respectively.; See details in the Section S9 of Supporting Information).

In agreement with the above observation, only an MD-HK-ALG sample

exhibited the selective uptake of MB (see Figures 5g–i).

We also confirmed that this dye sorption does

not lead to structural damage of HKUST-1 in MD-HK-ALG (see Section S10 of Supporting Information). Thus, we tentatively concluded that the MD-HK-ALG mixed matrix would be useful in ACS Paragon Plus Environment 6

Page 7 of 19 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

ACS Applied Materials & Interfaces

a utilization of size-exclusive molecular uptake.

Further, we speculate that MOF-MMs directly grown

using this in situ method will be suitable for use in applications to remove toxic molecules, presumably even at low concentration. We also attempted to fabricate a flexible MD-HK-ALG by adding poly(vinyl alcohol) (PVA) in Na+ALG solution (hereafter MD-HK-(ALG+PVA)M).

Figure 6 shows a photograph, SEM images, and

a XRD pattern of an approximately 140 µm-thick flexible MD-HK-(ALG+PVA)M. A XRD pattern indicates that the MOF crystallites formed in the MMM is definitely HKUST-1, and SEM images also show that the MOF crystallites are well surrounded by polymer matrix. Meanwhile, we also examined the in situ synthesis of MOF-74(Zn) to determine if this in situ strategy could be expanded to other MOFs. synthesis was observed (see Figure 7).

To conclude, a seemingly similar trend in the in situ

More precisely, while the metal-diffusional process allowed the

crystallization of MOF-74 in the polymer matrix, the ligand-diffusional process did not allow the crystallization.

Therefore, we tentatively concluded that this metal-diffusional in situ process can be

widely applicable to the synthesis of MOF-polymer mixed matrices if the MOF can be synthesized at room temperature or low temperature.

CONCLUSIONS In summary, we have demonstrated a strategy for the in situ synthesis of MOFs in a green ionic polymer, alginate, with the form of mixed matrix.

By exploiting this methodology, we found that the sequential

order of feeding metal ion or anionic ligand would lead to substantial difference in forming MMs.

For

the examples examined, while the infusion of Cu2+ ions into BTC3–-included ALG engendered high dispersivity and good junction-contact of HKUST-1 crystallites in the ALG matrix, the infusion of BTC3– ligand into Cu2+-exchanged ALG engendered the eggshell-shaped HKUST-1 layers on the external surface of MM spheres. We tentatively conclude that this behavior is attributed to differences in the size and charge between the metal ions and ligand molecules.

Using two molecular dyes, MB

and R6G whose sizes are critically different, we also demonstrated that the MOF-MM directly and ACS Paragon Plus Environment 7

ACS Applied Materials & Interfaces 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

Page 8 of 19

homogeneously grown using this methodology could be applied to size-selective molecular uptake. Further, we demonstrated that this in situ strategy can be not only applicable to the fabrication of flexible MMMs but also expandable to the synthesis of other MOF-MM such as MOF-74(Zn) mixed matrix. We anticipate that this in situ strategy for the growth of MOFs within environmentally friendly ionic polymers will prove adoptable or transferable to other MOFs, and further expandable and therefore applicable to other biocompatible polymers. Also, we expect that this in situ strategy can improve the chemical stability of the MOFs contained in MMs by harmoniously encapsulating them inside polymer matrix if a MOF-polymer MM can be carefully and prudently designed.

ASSOCIATED CONTENT Supporting Information Experimental details, and TGA, UV–vis absorption, XRD, SEM, and EDS data. The Supporting Information is available free of charge on the ACS Publications website at DOI: xxx. AUTHOR INFORMATION Corresponding Author [email protected] Notes The authors declare no competing financial interest. ACKNOWLEDGEMENTS This work was supported by the Ministry of Science and ICT (MSIT) of Korea under the auspices of the Basic Science Research Program sponsored by the National Research Foundation (NRF) (Grant No. NRF-2016R1A2B2014918) and by the DGIST R&D Program (Grant No. 18-BD-0403). REFERENCES (1) (2) (3) (4)

(5)

(6) (7)

(8)

O'Keeffe, M.; Peskov, M. A.; Ramsden, S. J.; Yaghi, O. M. The Reticular Chemistry Structure Resource (RCSR) Database of, and Symbols for, Crystal Nets. Acc. Chem. Res. 2008, 41, 1782-1789. Horike, S.; Shimomura, S.; Kitagawa, S. Soft Porous Crystals. Nat. Chem. 2009, 1, 695-704. Yu, J.; Xie, L. H.; Li, J. R.; Ma, Y.; Seminario, J. M.; Balbuena, P. B. CO2 Capture and Separations Using MOFs: Computational and Experimental Studies. Chem. Rev. 2017, 117, 9674-9754. Shah, M. S.; Tsapatsis, M.; Siepmann, J. I. Hydrogen Sulfide Capture: From Absorption in Polar Liquids to Oxide, Zeolite, and Metal-Organic Framework Adsorbents and Membranes. Chem. Rev. 2017, 117, 97559803. Adil, K.; Belmabkhout, Y.; Pillai, R. S.; Cadiau, A.; Bhatt, P. M.; Assen, A. H.; Maurin, G.; Eddaoudi, M. Gas/Vapour Separation Using Ultra-Microporous Metal-Organic Frameworks: Insights into the Structure/Separation Relationship. Chem. Soc. Rev. 2017, 46, 3402-3430. Rieth, A. J.; Tulchinsky, Y.; Dinca, M. High and Reversible Ammonia Uptake in Mesoporous Azolate Metal-Organic Frameworks with Open Mn, Co, and Ni Sites. J. Am. Chem. Soc. 2016, 138, 9401-9404. Gao, C. Y.; Tian, H. R.; Ai, J.; Li, L. J.; Dang, S.; Lan, Y. Q.; Sun, Z. M. A Microporous Cu-MOF with Optimized Open Metal Sites and Pore Spaces for High Gas Storage and Active Chemical Fixation of CO2. Chem. Commun. 2016, 52, 11147-11150. Levine, D. J.; Runcevski, T.; Kapelewski, M. T.; Keitz, B. K.; Oktawiec, J.; Reed, D. A.; Mason, J. A.; Jiang, H. Z.; Colwell, K. A.; Legendre, C. M.; FitzGerald, S. A.; Long, J. R. Olsalazine-Based MetalACS Paragon Plus Environment 8

Page 9 of 19 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

(9)

(10) (11)

(12)

(13) (14)

(15)

(16)

(17)

(18)

(19) (20) (21) (22)

(23)

(24)

(25)

(26) (27)

ACS Applied Materials & Interfaces

Organic Frameworks as Biocompatible Platforms for H2 Adsorption and Drug Delivery. J. Am. Chem. Soc. 2016, 138, 10143-10150. Bloch, E. D.; Queen, W. L.; Hudson, M. R.; Mason, J. A.; Xiao, D. J.; Murray, L. J.; Flacau, R.; Brown, C. M.; Long, J. R. Hydrogen Storage and Selective, Reversible O2 Adsorption in a Metal-Organic Framework with Open Chromium(II) Sites. Angew. Chem., Int. Ed. 2016, 55, 8605-8609. Kumar, K. V.; Preuss, K.; Titirici, M. M.; Rodriguez-Reinoso, F. Nanoporous Materials for the Onboard Storage of Natural Gas. Chem. Rev. 2017, 117, 1796-1825. Bobbitt, N. S.; Mendonca, M. L.; Howarth, A. J.; Islamoglu, T.; Hupp, J. T.; Farha, O. K.; Snurr, R. Q. Metal-Organic Frameworks for the Removal of Toxic Industrial Chemicals and Chemical Warfare Agents. Chem. Soc. Rev. 2017, 46, 3357-3385. Zheng, H.; Zhang, Y.; Liu, L.; Wan, W.; Guo, P.; Nystrom, A. M.; Zou, X. One-Pot Synthesis of Metal Organic Frameworks with Encapsulated Target Molecules and Their Applications for Controlled Drug Delivery. J. Am. Chem. Soc. 2016, 138, 962-968. Wu, M. X.; Yang, Y. W. Metal-Organic Framework (MOF)-Based Drug/Cargo Delivery and Cancer Therapy. Adv. Mater. 2017, 29, 1606134. Teplensky, M. H.; Fantham, M.; Li, P.; Wang, T. C.; Mehta, J. P.; Young, L. J.; Moghadam, P. Z.; Hupp, J. T.; Farha, O. K.; Kaminski, C. F.; Fairen-Jimenez, D. Temperature Treatment of Highly Porous ZirconiumContaining Metal-Organic Frameworks Extends Drug Delivery Release. J. Am. Chem. Soc. 2017, 139, 7522-7532. Noh, H.; Cui, Y.; Peters, A. W.; Pahls, D. R.; Ortuno, M. A.; Vermeulen, N. A.; Cramer, C. J.; Gagliardi, L.; Hupp, J. T.; Farha, O. K. An Exceptionally Stable Metal-Organic Framework Supported Molybdenum(VI) Oxide Catalyst for Cyclohexene Epoxidation. J. Am. Chem. Soc. 2016, 138, 14720-14726. Deria, P.; Gomez-Gualdron, D. A.; Hod, I.; Snurr, R. Q.; Hupp, J. T.; Farha, O. K. Framework-TopologyDependent Catalytic Activity of Zirconium-Based (Porphinato)zinc(II) MOFs. J. Am. Chem. Soc. 2016, 138, 14449-14457. Li, Z.; Schweitzer, N. M.; League, A. B.; Bernales, V.; Peters, A. W.; Getsoian, A. B.; Wang, T. C.; Miller, J. T.; Vjunov, A.; Fulton, J. L.; Lercher, J. A.; Cramer, C. J.; Gagliardi, L.; Hupp, J. T.; Farha, O. K. SinteringResistant Single-Site Nickel Catalyst Supported by Metal-Organic Framework. J. Am. Chem. Soc. 2016, 138, 1977-1982. Johnson, J. A.; Petersen, B. M.; Kormos, A.; Echeverria, E.; Chen, Y. S.; Zhang, J. A New Approach to Non-Coordinating Anions: Lewis Acid Enhancement of Porphyrin Metal Centers in a Zwitterionic MetalOrganic Framework. J. Am. Chem. Soc. 2016, 138, 10293-10298. Korzynski, M. D.; Dinca, M. Oxidative Dehydrogenation of Propane in the Realm of Metal-Organic Frameworks. ACS Cent. Sci. 2017, 3, 10-12. Zhu, L.; Liu, X. Q.; Jiang, H. L.; Sun, L. B. Metal-Organic Frameworks for Heterogeneous Basic Catalysis. Chem. Rev. 2017, 117, 8129-8176. Yang, Q.; Xu, Q.; Jiang, H. L. Metal-Organic Frameworks Meet Metal Nanoparticles: Synergistic Effect for Enhanced Catalysis. Chem. Soc. Rev. 2017, 46, 4774-4808. Rogge, S. M. J.; Bavykina, A.; Hajek, J.; Garcia, H.; Olivos-Suarez, A. I.; Sepulveda-Escribano, A.; Vimont, A.; Clet, G.; Bazin, P.; Kapteijn, F.; Daturi, M.; Ramos-Fernandez, E. V.; Llabresi Xamena, F. X.; Speybroeck, V. V.; Gascon, J. Metal-Organic and Covalent Organic Frameworks as Single-Site Catalysts. Chem. Soc. Rev. 2017, 46, 3134-3184. Kornienko, N.; Zhao, Y.; Kley, C. S.; Zhu, C.; Kim, D.; Lin, S.; Chang, C. J.; Yaghi, O. M.; Yang, P. MetalOrganic Frameworks for Electrocatalytic Reduction of Carbon Dioxide. J. Am. Chem. Soc. 2015, 137, 14129-14135. Hod, I.; Sampson, M. D.; Deria, P.; Kubiak, C. P.; Farha, O. K.; Hupp, J. T. Fe-Porphyrin-Based MetalOrganic Framework Films as High-Surface Concentration, Heterogeneous Catalysts for Electrochemical Reduction of CO2. ACS Catalysis 2015, 5, 6302-6309. Talin, A. A.; Centrone, A.; Ford, A. C.; Foster, M. E.; Stavila, V.; Haney, P.; Kinney, R. A.; Szalai, V.; Gabaly, F. E.; Yoon, H., P.; Léonard, F.; Allendorf, M. D. Tunable Electrical Conductivity in Metal-Organic Framework Thin-Film Devices. Science 2014, 343, 66-69. Sun, L.; Campbell, M. G.; Dinca, M. Electrically Conductive Porous Metal-Organic Frameworks. Angew. Chem., Int. Ed. 2016, 55, 3566-3579. Le Ouay, B.; Boudot, M.; Kitao, T.; Yanagida, T.; Kitagawa, S.; Uemura, T. Nanostructuration of PEDOT in Porous Coordination Polymers for Tunable Porosity and Conductivity. J. Am. Chem. Soc. 2016, 138, 10088-10091. ACS Paragon Plus Environment 9

ACS Applied Materials & Interfaces 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

Page 10 of 19

(28) Ji, H.; Hwang, S.; Kim, K.; Kim, C.; Jeong, N. C. Direct in Situ Conversion of Metals into Metal-Organic Frameworks: A Strategy for the Rapid Growth of MOF Films on Metal Substrates. ACS Appl. Mater. Interfaces 2016, 8, 32414-32420. (29) Campbell, M. G.; Sheberla, D.; Liu, S. F.; Swager, T. M.; Dinca, M. Cu3(hexaiminotriphenylene)2: An Electrically Conductive 2D Metal-Organic Framework for Chemiresistive Sensing. Angew. Chem., Int. Ed. 2015, 54, 4349-4352. (30) Wang, T. C.; Hod, I.; Audu, C. O.; Vermeulen, N. A.; Nguyen, S. T.; Farha, O. K.; Hupp, J. T. Rendering High Surface Area, Mesoporous Metal-Organic Frameworks Electronically Conductive. ACS Appl. Mater. Interfaces 2017, 9, 12584-12591. (31) Wales, D. J.; Grand, J.; Ting, V. P.; Burke, R. D.; Edler, K. J.; Bowen, C. R.; Mintova, S.; Burrows, A. D. Gas Sensing Using Porous Materials for Automotive Applications. Chem. Soc. Rev. 2015, 44, 4290-4321. (32) Huang, R. W.; Wei, Y. S.; Dong, X. Y.; Wu, X. H.; Du, C. X.; Zang, S. Q.; Mak, T. C. W. Hypersensitive Dual-Function Luminescence Switching of a Silver-Chalcogenolate Cluster-Based Metal–Organic Framework. Nat. Chem. 2017, 9, 689-697. (33) Gassensmith, J. J.; Kim, J. Y.; Holcroft, J. M.; Farha, O. K.; Stoddart, J. F.; Hupp, J. T.; Jeong, N. C. A Metal-Organic Framework-Based Material for Electrochemical Sensing of Carbon Dioxide. J. Am. Chem. Soc. 2014, 136, 8277-8282. (34) Jeong, N. C.; Samanta, B.; Lee, C. Y.; Farha, O. K.; Hupp, J. T. Coordination-Chemistry Control of Proton Conductivity in the Iconic Metal-Organic Framework Material HKUST-1. J. Am. Chem. Soc. 2012, 134, 51-54. (35) Joarder, B.; Lin, J. B.; Romero, Z.; Shimizu, G. K. H. Single Crystal Proton Conduction Study of a Metal Organic Framework of Modest Water Stability. J. Am. Chem. Soc. 2017, 139, 7176-7179. (36) Kim, S. B.; Kim, J. Y.; Jeong, N. C.; Ok, K. M. Anisotropic Li+ ion Conductivity in a Large Single Crystal of a Co(III) Coordination Complex. Inorg. Chem. Front. 2017, 4, 79-83. (37) Meng, X.; Wang, H. N.; Song, S. Y.; Zhang, H. J. Proton-Conducting Crystalline Porous Materials. Chem. Soc. Rev. 2017, 46, 464-480. (38) Chen, Q.; Sun, J.; Li, P.; Hod, I.; Moghadam, P. Z.; Kean, Z. S.; Snurr, R. Q.; Hupp, J. T.; Farha, O. K.; Stoddart, J. F. A Redox-Active Bistable Molecular Switch Mounted inside a Metal-Organic Framework. J. Am. Chem. Soc. 2016, 138, 14242-14245. (39) D'Alessandro, D. M. Exploiting Redox Activity in Metal-Organic Frameworks: Concepts, Trends and Perspectives. Chem. Commun. 2016, 52, 8957-8971. (40) Li, P.; Moon, S. Y.; Guelta, M. A.; Harvey, S. P.; Hupp, J. T.; Farha, O. K. Encapsulation of a Nerve Agent Detoxifying Enzyme by a Mesoporous Zirconium Metal-Organic Framework Engenders Thermal and Long-Term Stability. J. Am. Chem. Soc. 2016, 138, 8052-8055. (41) Bae, J.; Choi, J. S.; Hwang, S.; Yun, W. S.; Song, D.; Lee, J.; Jeong, N. C. Multiple Coordination Exchanges for Room-Temperature Activation of Open-Metal Sites in Metal-Organic Frameworks. ACS Appl. Mater. Interfaces 2017, 9, 24743-24752. (42) Zhu, H.; Zhang, Q.; Zhu, S. Alginate Hydrogel: A Shapeable and Versatile Platform for In Situ Preparation of Metal-Organic Framework-Polymer Composites. ACS Appl. Mater. Interfaces 2016, 8, 17395-17401. (43) Matsumoto, M.; Kitaoka, T. Ultraselective Gas Separation by Nanoporous Metal-Organic Frameworks Embedded in Gas-Barrier Nanocellulose Films. Adv. Mater. 2016, 28, 1765-1769. (44) Su, Z.; Chen, J. H.; Sun, X.; Huang, Y. H.; Dong, X. Amine-Functionalized Metal Organic Framework (NH2-MIL-125(Ti)) Incorporated Sodium Alginate Mixed Matrix Membranes for Dehydration of Acetic Acid by Pervaporation. RSC Adv. 2015, 5, 99008-99017. (45) Zhu, H.; Yang, X.; Cranston, E. D.; Zhu, S. Flexible and Porous Nanocellulose Aerogels with High Loadings of Metal-Organic-Framework Particles for Separations Applications. Adv. Mater. 2016, 28, 76527657. (46) Denny, M. S.; Cohen, S. M. In Situ Modification of Metal-Organic Frameworks in Mixed-Matrix Membranes. Angew. Chem., Int. Ed. 2015, 54, 9029-9032. (47) Cao, L.; Lv, F.; Liu, Y.; Wang, W.; Huo, Y.; Fu, X.; Sun, R.; Lu, Z. A High Performance O2 Selective Membrane Based on CAU-1-NH2@Polydopamine and the PMMA Polymer for Li–Air Batteries. Chem. Commun. 2015, 51, 4364-4367. (48) Anjum, M. W.; Vermoortele, F.; Khan, A. L.; Bueken, B.; De Vos, D. E.; Vankelecom, I. F. Modulated UiO66-Based Mixed-Matrix Membranes for CO2 Separation. ACS Appl. Mater. Interfaces 2015, 7, 2519325201. (49) Lin, R.; Ge, L.; Liu, S.; Rudolph, V.; Zhu, Z. Mixed-Matrix Membranes with Metal-Organic FrameworkACS Paragon Plus Environment 10

Page 11 of 19 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

ACS Applied Materials & Interfaces

Decorated CNT Fillers for Efficient CO2 Separation. ACS Appl. Mater. Interfaces 2015, 7, 14750-14757. (50) Deng, Y. H.; Chen, J. T.; Chang, C. H.; Liao, K. S.; Tung, K. L.; Price, W. E.; Yamauchi, Y.; Wu, K. C. W. A Drying-Free, Water-Based Process for Fabricating Mixed-Matrix Membranes with Outstanding Pervaporation Performance. Angew. Chem., Int. Ed. 2016, 128, 12985-12988. (51) Denny, M. S.; Moreton, J. C.; Benz, L.; Cohen, S. M. Metal-Organic Frameworks for Membrane-Based Separations. Nat. Rev. Mater. 2016, 1, 16078. (52) Dechnik, J.; Gascon, J.; Doonan, C. J.; Janiak, C.; Sumby, C. J. Mixed-Matrix Membranes. Angew. Chem., Int. Ed. 2017, 56, 9292-9310. (53) Zhang, R.; Ji, S.; Wang, N.; Wang, L.; Zhang, G.; Li, J. R. Coordination-Driven In Situ Self-Assembly Strategy for the Preparation of Metal-Organic Framework Hybrid Membranes. Angew. Chem., Int. Ed. 2014, 53, 9775-9779. (54) Hess, S. C.; Grass, R. N.; Stark, W. J. MOF Channels within Porous Polymer Film: Flexible, SelfSupporting ZIF-8 Poly(ether sulfone) Composite Membrane. Chem. Mater. 2016, 28, 7638-7644. (55) Zhao, C. W.; Ma, J. P.; Liu, Q. K.; Wang, X. R.; Liu, Y.; Yang, J.; Yang, J. S.; Dong, Y. B. An In Situ SelfAssembled Cu4I4-MOF-Based Mixed Matrix Membrane: A Highly Sensitive and Selective Naked-Eye Sensor for Gaseous HCl. Chem. Commun. 2016, 52, 5238-5241. (56) Lee, K. Y.; Mooney, D. J. Alginate: Properties and Biomedical Applications. Prog. Polym. Sci. 2012, 37, 106-126. (57) In this study, Ca2+-ion exchange of linear Na+ALG polymer was simultaneously proceeded in the process of BTC3–-inclusion in alginate to allow the linear polymer to be cross-linked and thereby, to make the polymer solidify with a sphere shape. (58) Huheey, J. E.; Keiter, E. A.; Keiter, R. L. Inorganic Chemistry: Principles of Structure and Reactivity. 4th ed.; HarperCollins Publishers: New York, 1993; p 114. (59) Shannon, R. D. Revised Effective Ionic-Radii and Systematic Studies of Interatomic Distances in Halides and Chalcogenides. Acta Crystallogr. A 1976, A32, 751-767.

ACS Paragon Plus Environment 11

ACS Applied Materials & Interfaces 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

Page 12 of 19

FIGURES

Route A: ligand-diffusional (LD) in situ synthesis M2+

Ln-

Route B: metal ion-diffusional (MD) in situ synthesis Ln-

M2+ 2+

with Ca

+

Na 2+ Ca

2+

2+

2+

M = Cu or Zn n– 3– 4– L = BTC or DOBDC

Alginate polymer chain MOF = HKUST-1 or MOF-74(Zn)

Figure 1. Schematic illustrations of ligand-diffusional (route A) and metal ion-diffusional (route B) in situ syntheses of MOF crystals in alginate polymer matrix.

ACS Paragon Plus Environment 12

Page 13 of 19

OM

SEM: Cross-Sectioned Internal Area

SEM: Outer Surface

(ii) Near Surface

(iii) Far Surface

(iv) Core Region

0 min

Cu2+ALG

(i) Top Surface

(ii) (iii) (iv)

60 min

30 min

20 min

10 min

5 min

(i)

LD-HK-ALG (reaction time)

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

ACS Applied Materials & Interfaces

500 µm

5 µm

10 µm

2+

10 µm

10 µm

Figure 2. OM and SEM images of cross-sectioned Cu ALG and LD-HK-ALG spheres. The reaction time for the diffusion of 3– 2+ BTC ligand in Cu ALG spheres was controlled from 5 to 60 min. SEM images show the external surface and internal areas of the cross-sectioned spheres at near surface, far surface, and core region, as indicated.

ACS Paragon Plus Environment 13

ACS Applied Materials & Interfaces

SEM: Cross-Sectioned Internal Area

SEM: Outer Surface

OM

(ii) Near Surface

(iii) Far Surface

(iv) Core Region

0 min

Ca2+ALG

(i) Top Surface

(ii) (iii) (iv)

60 min

30 min

20 min

10 min

5 min

(i)

MD-HK-ALG (reaction time)

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

Page 14 of 19

500 µm

5 µm

10 µm

3–

2+

10 µm

10 µm

Figure 3. OM and SEM images of cross-sectioned BTC -containing Ca ALG and MD-HK-ALG spheres. The reaction time for 2+ 3– the diffusion of Cu ion in BTC -containing ALG spheres was controlled from 5 to 60 min. SEM images show the external surface and internal areas of the cross-sectioned spheres at near surface, far surface, and core region, as indicated.

ACS Paragon Plus Environment 14

Page 15 of 19 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

ACS Applied Materials & Interfaces

3–

2+

(a) Route A: BTC -Diffusion in Cu ALG LD-HK-ALG (60 min) LD-HK-ALG (30 min) LD-HK-ALG (20 min) LD-HK-ALG (10 min) LD-HK-ALG (05 min)

Cu2+ALG HKUST-1 Powder 10

20

30

2+

40 3–

(b) Route B: Cu -Diffusion in BTC -ALG MD-HK-ALG (60 min) MD-HK-ALG (30 min) MD-HK-ALG (20 min) MD-HK-ALG (10 min) MD-HK-ALG (05 min) Ca2+ALG HKUST-1 Powder 10

20

30

40

2θ (°)

Figure 4. XRD patterns of (a) LD-HK-ALG and (b) MD-HK-ALG spheres, where HKUST-1 crystals were in situ synthesized with 2+ 2+ controlled diffusional reaction time for 5 - 60 min. XRD patterns of Cu ALG and Cu ALG spheres and a HKUST-1 powder sample were taken for comparison.

ACS Paragon Plus Environment 15

ACS Applied Materials & Interfaces

(a) MB sorption in MD-HK-ALG

0.2 0.1 0.0

0.3 0.2 0.1 0.0

500

550

600

650

700

(d) R6G sorption in MD-HK- ALG 0 min 10 30 60 120 180 240 300 360

0.5 0.4 0.3 0.2

550

600

650

0.4 0.3 0.2

0.0

0.0 500

550

600

650

700

3.0 2.0

MD-HK-ALG

1.0 0

60

120

180

240

300

360

(f) Plots of R6G sorption LD-HK-ALG

6.0

0.5

0.1

4.0

700

0.6

0.1 450

500

(e) R6G sorption in LD-HK- ALG

Absorbance

0.6

LD-HK-ALG

5.0

0.0

450

Concentration (µM)

450

Absorbance

Concentration (µM)

0.3

(c) Plots of MB sorption 6.0

0.4

Absorbance

Absorbance

(b) MB sorption in LD-HK- ALG

0 min 10 30 60 120 180 240 300 360

0.4

5.0

MD-HK-ALG

4.0 3.0 2.0 1.0 0.0

450

500

550

600

650

700

0

60

120

180

240

300

360

(g) MB+R6G sorption in MD-HK- ALG (h) MB+R6G sorption in LD-HK- ALG (i) Plots of MB+R6G Sorption R6G

R6G

0 min 10 30 60 120 180 240 300 360

0.4 0.3 0.2

MB

MB

0.5

0.1

Concentration (µM)

0.5

R6G@LD-HK-ALG

0.6

Absorbance

0.6

Absorbance

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

Page 16 of 19

0.4 0.3 0.2 0.1

0.0

0.0 450

500

550

600

650

Wavelength (nm)

700

6.0

R6G@MD-HK-ALG

5.0

MB@LD-HK-ALG

4.0 3.0 2.0

MB@MD-HK-ALG

1.0 0.0

450

500

550

600

650

700

Wavelength (nm)

0

60

120

180

240

300

360

Time (min)

Figure 5. Time-course monitoring of UV-vis absorption spectra of initially 6 µM (a-b) MB, (d-e) R6G, and (g-h) mixed MB+R6G solutions that contained (a, d, g) MD-HK-ALG and (b, e, h) LD-HK-ALG spheres. Plots of absorbance of (c) MB, (f) R6G, and (i) mixed MB+R6G solutions at the λmaxs of 652 and 528 nm with respect to the exposure time.

ACS Paragon Plus Environment 16

Page 17 of 19 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

ACS Applied Materials & Interfaces

(a)

(b) Side View

(c) Top View

(d) Bottom View 10 µm

50 µm

(e)

MD-HK-(ALG+PVA)M

10

20

30

40

2θ (°)

Figure 6. (a) Photograph, (b-d) SEM images, and (e) XRD pattern of an approximately 140 µm-thick flexible MD-HK(ALG+PVA) membrane.

ACS Paragon Plus Environment 17

ACS Applied Materials & Interfaces

Near Surface

Top Surface

MD-MOF74-ALG

Core Region

Top View

(a)

Cross-Sectioned View

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

Page 18 of 19

LD-MOF74-ALG

5 µm

5 µm

10 µm

10 µm

10 µm

10 µm

(b)

MD-MOF74-ALG

LD-MOF74-ALG

MOF74 Powder 10

20

30

40

2θ (°)

Figure 7. (a) SEM images of cross-sectioned MD-MOF74-ALG and LD-MOF74-ALG spheres. SEM images show the external surface and internal areas of the cross-sectioned spheres at near surface and core region, as indicated. (b) XRD patterns of MD-MOF74-ALG and LD-MOF74-ALG spheres. XRD pattern of a MOF-74(Zn) powder was also taken for comparison.

ACS Paragon Plus Environment 18

Page 19 of 19 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

ACS Applied Materials & Interfaces

Table of Contents (TOC) Artwork

In situ synthesis of metal-organic frameworks in an ionic polymer matrix behaves differently depending on the subject of diffusion of ingredients.

ACS Paragon Plus Environment 19