Facile Conversion of Hydroxy Double Salts to Metal-Organic Frameworks Using Metal Oxide Particles and Atomic Layer Deposition Thin-Film Templates

Transcription

1 Supporting Information Facile Conversion of Hydroxy Double Salts to Metal-Organic Frameworks Using Metal Oxide Particles and Atomic Layer Deposition Thin-Film Templates Junjie Zhao, William T. Nunn, Paul C. Lemaire, Yiliang Lin, Michael D. Dickey, Christopher J. Oldham, Howard J. Walls, Gregory W. Peterson #, Mark D. Losego, and Gregory N. Parsons *, Department of Chemical and Biomolecular Engineering, North Carolina State University, 911 Partners Way, Raleigh, NC 27695, United States. RTI International, 3040 East Cornwallis Road, Research Triangle Park, NC 27709, United States. # Edgewood Chemical Biological Center, 5183 Blackhawk Road, Aberdeen Proving Ground, MD 21010, United States. School of Materials Science and Engineering, Georgia Institute of Technology, 771 Ferst Dr. NW, Atlanta, GA 30332, United States. S1

2 Table of Contents Experimental Section... S3 Synthesis of HKUST-1 MOF Using (Zn,Cu) Hydroxy Double Salt Intermediate... S3 Synthesis of Cu-BDC MOF Using (Zn,Cu) Hydroxy Double Salt Intermediate... S3 Synthesis of IRMOF-3 using (Zn,Zn) Hydroxy Double Salt Intermediate... S4 Synthesis of ZIF-8 using (Zn,Zn) Hydroxy Double Salt Intermediate... S4 Atomic Layer Deposition (ALD) for ZnO Thin Films... S5 HKUST-1 Precursor Solutions... S5 Fabrication Procedure for HKUST-1 Patterns... S5 Synthesis of HKUST-1 Coatings on Polystyrene Spheres... S6 Synthesis of HKUST-1 Coatings on Silicon Wafers... S6 Synthesis of HKUST-1 Coatings on Fibers... S6 Space-Time-Yield (STY) Calculation... S7 Material Characterization... S7 Breakthrough Test for NH 3 and H 2 S... S9 Breakthrough Data Analysis... S9 Figure S1... S11 Figure S2... S12 Figure S3... S13 Figure S4... S14 Table S1... S15 Table S2... S15 Figure S5... S16 Figure S6... S17 Figure S7... S18 Figure S8... S19 Figure S9... S20 Figure S10... S21 Figure S11... S22 Figure S12... S23 Figure S13... S24 Figure S14... S25 S2

3 Experimental Section Synthesis of HKUST-1 MOF Using (Zn,Cu) Hydroxy Double Salt Intermediate g of ZnO powder ( 99.0%, Sigma-Aldrich) was dispersed in 8 ml of deionized water using sonication for 5~10 min to form the nanoslurry g of Cu(NO 3 ) 2 3H 2 O (99-104%, Sigma-Aldrich) was dissolved in 8 ml deionized water (n(zno):n(cu(no 3 ) 2 )=1:2), and 0.840g of 1,3,5-benzenetricarboxylic acid (H 3 BTC, 95%, Aldrich) was dissolved in 16 ml ethanol (200 proof, Koptec) separately. After the Cu(NO 3 ) 2 aqueous solution and H 3 BTC ethanolic solution were prepared, ZnO nanoslurries were mixed with 16 ml of DMF (Fisher Scientific), to which the Cu(NO 3 ) 2 aqueous solution was added and next the H 3 BTC ethanolic solution under magnetic stirring. After 1 min of reaction, the powder product was immediately filtered with a polypropylene membrane filter (0.45 μm pore size, Whatman) and washed with ethanol (50 ml, 3 times). The HKUST-1 product was dried in a fume hood for 30 min and then dried in vacuum oven (~0.01 inhg) at 120 for 6 hours. No HKUST-1 was formed in the control experiments without ZnO nanoslurries. Synthesis of Cu-BDC MOF Using (Zn,Cu) Hydroxy Double Salt Intermediate The synthesis of Cu-BDC MOF from (Zn,Cu) HDS is similar to HKUST g of ZnO powder was dispersed in 6 ml of deionized water using sonication for 5~10 min g of Cu(NO 3 ) 2 3H 2 O was dissolved in 6 ml deionized water (n(zno):n(cu(no 3 ) 2 )=1:2), and 0.673g of 1,4-benzenedicarboxylic acid (H 2 BDC, 98%, Aldrich) was dissolved in 25 ml DMF separately. After the Cu(NO 3 ) 2 aqueous solution and H 2 BDC DMF solution were prepared, ZnO nanoslurries were mixed with 6 ml of DMF, to which the Cu(NO 3 ) 2 aqueous solution was added and next the H 2 BDC DMF solution under fast magnetic stirring. After 2 min of reaction, the S3

4 turquoise powder product was immediately filtered and dried in air. Powder XRD pattern for the Cu-BDC product was measured when the sample was still damp. Synthesis of IRMOF-3 using (Zn,Zn) Hydroxy Double Salt Intermediate (Zn,Zn) hydroxy double salt was synthesized at room temperature using a previously reported method. 1 Specifically, g (5 mmol) of ZnO was dispersed in 5 ml of deionized water, and 1.10 g (5 mmol) of Zn(CH 3 CO 2 ) 2 2H 2 O ( 99%, Sigma-Aldrich) was dissolved in 5 ml of deionized water. Zinc acetate aqueous solution was added to the ZnO suspension under strong magnetic stirring at room temperature. After 24 hours, the mixture converted into a gel-like viscous fluid as the (Zn,Zn) hydroxy acetate HDS formed g of (Zn,Zn) HDS suspension was transferred to a beaker, and mixed with 25 ml of 2-aminoterephthalic acid (0.272 g, 1.5 mmol, 99%, Acros Organics) DMF solution at room temperature for 10 min. The product was then filtered and dried in air. Powder XRD pattern for the product was collected when the sample was still damp. Synthesis of ZIF-8 using (Zn,Zn) Hydroxy Double Salt Intermediate The synthesis of ZIF-8 from (Zn,Zn) HDS is similar to IRMOF-3. (Zn,Zn) hydroxy double salt was synthesized at room temperature by mixing 5 ml of ZnO aqueous suspension (1 M) with 5 ml of Zn(CH 3 CO 2 ) 2 aqueous solution (1 M) and 5 ml of DMF for 24 h. 3 ml of (Zn,Zn) HDS suspension was added to 9 ml of 2-methylimidazole (0.493 g, 6 mmol, 99%, Aldrich) DMF solution under fast magnetic stirring at room temperature for 10 min. The product was then filtered and dried in air. Powder XRD pattern for the product was collected when the sample was still damp. S4

5 Atomic Layer Deposition (ALD) for ZnO Thin Films ALD ZnO thin films were deposited onto polystyrene microspheres, silicon wafers, polypropylene and polyacrylonitrile fiber mats using a homemade hot-wall viscous-flow ALD reactor that has been described in our previous work. 2 The deposition pressure was ~2 Torr, and the temperature was 100. In a typical ALD ZnO cycle, diethyl zinc (DEZ, 95%, STREM Chemicals) was first dosed to the reactor chamber for 2 s, followed by 60 s of N 2 (dried with an Entegris gatekeeper) purge. After DEZ dose and N 2 purge, deionized water was dosed for 2 s, and another 60s of N 2 purge completed the ALD cycle. HKUST-1 Precursor Solutions g of Cu(NO 3 ) 2 3H 2 O was dissolved in 12 ml deionized water (Solution A), and 0.420g of H 3 BTC was dissolved in 12 ml ethanol (Solution B). For reaction mechanism studies and MOF patterning, Solution B was mixed with equal volumes of DMF and deionized H 2 O, making a H 3 BTC solution (referred to as Solution B ) with mixed solvents (DMF:EtOH:H 2 O=1:1:1). In the dip coating processes for growing MOFs onto different substrates, 3 ml of Solution A was first mixed with 3mL DMF and then 3mL of Solution B in a 20 ml scintillation vial (VWR International) under mild magnetic stirring for 1 min. The mixed precursor solution (Solution M) was then used for growing HKUST-1 coatings on ZnO-coated substrates. Fabrication Procedure for HKUST-1 Patterns Negative photoresist SU (Microchem) was used as received and spun-coated (3000 rpm for 30 s) onto the ALD ZnO coated Si wafer. After soft baking S5

6 at 65 for 1 min and 95 for 7 min, the wafer was exposed to UV lamp (INTELLI-RAY 400, 60% intensity) for 5 s. The wafer was then baked at 65 for 1 min and 95 for 6 min, and subsequently dipped into SU-8 developer. The pre-patterned sample was rinsed in IPA and ethanol, and dried in compressed air. During MOF patterning, the sample was soaked in Solution A for 1 min, and washed in ethanol for 1 min. The wafer was then transferred to Solution B for 45~60 s, followed with gentle ethanol rinse for 5 min. The patterned sample was finally dried in compressed air. Synthesis of HKUST-1 Coatings on Polystyrene Spheres 80 μl Polybead polystyrene (PS) microspheres in aqueous suspension (3 μm diameter, 2.5% solids in water, Polysciences Inc.) were spun-coat onto silicon wafers pretreated with O 2 plasma. The prepared sample was then coated with 200 cycles of ALD ZnO, and then dipped in Solution M for 1 min. The sample was then slowly lifted out of the MOF precursor solution, and carefully transferred and soaked in ethanol for 5 min. After ethanol rinsing, the samples were dried in air. Synthesis of HKUST-1 Coatings on Silicon Wafers 200 cycles of ALD ZnO were deposited onto silicon wafers using the abovementioned process. After ALD coating, Si wafers were soaked in Solution M for 1 min, and then carefully transferred to ethanol for 5 min of soaking and finally dried in air. Synthesis of HKUST-1 Coatings on Fibers Nonwoven polypropylene (PP) microfiber mats were used as received from the S6

7 Nonwovens Cooperative Research Center (NCRC) at North Carolina State University. Electrospun polyacrylonitrile (PAN) nanofibers were used as received from RTI International. 200 cycles of ALD ZnO were deposited onto these fiber mats using the process described above. After ALD coating, the PP/ZnO and PAN/ZnO mats were soaked in the Solution M for 1 min and 5 min respectively, dried in air for 1 hour, and rinsed in methanol for solvent exchange for 1 day. The MOF coated fibers were finally dried at room temperature under vacuum. Space-Time-Yield (STY) Calculation The space-time-yield (STY, in units of kg m -3 d -1 ) was calculated using the following equation: STY = m MOF V solution τ (1) where m MOF is the dry mass (g) for the MOF powder obtained from the rapid synthesis, V solution is the total volume (cm 3 ) for the mixed precursor solution, and τ is the residence time (min). Material Characterization Scanning electron microscopic (SEM) images were taken using a JEOL JSM 6010 SEM and an FEI Verios 460L field emission SEM. A thin layer of Au-Pd (5~10 nm) was sputter-coated onto all samples before SEM imaging. Energy dispersive X-ray (EDX) analysis for HKUST-1 powder was performed using an FEI Verios 460L field emission SEM equipped with an Oxford energy dispersive X-ray spectrometer. The cross sections of the MOF-coated silicon S7

8 wafers were prepared with an FEI Quanta 3D FEG focused ion beam (FIB), and imaged using an FEI Titan probe aberration corrected scanning transmission electron microscope (STEM). High-resolution EDX was analyzed using the SuperX Energy Dispersive Spectrometry (SuperX EDS) system installed on the FEI Titan STEM. Time-of-flight secondary ion mass spectroscopy (TOF-SIMS) analysis for HKUST-1 powder was performed using a TOF-SIMS V Instrument (ION TOF, Inc. Chestnut Ridge, NY). Perkin Elmer 8000 Inductively-coupled plasma-optical emission spectroscopy (ICP-OES) was used for analyzing the concentration of Cu and Zn in the MOF powder and the residue solution collected after filtration. Before ICP-OES analysis, the MOF powder was digested in a mixture of 5 ml HNO 3, 3 ml HCl and 0.5 ml H 2 O 2 for 1 hour using a CEM Mars 5 microwave digesting system. 3 X-ray diffraction (XRD) was conducted with a Rigaku SmartLab X-ray diffraction tool (Cu Kα X-ray source) for crystalline phase analysis. MOF powder diffraction patterns were also simulated using Mercury 3.0 software and the crystallographic information files from Cambridge Crystallographic Data Centre (CCDC for HKUST-1, CCDC for Cu-BDC, CCDC for IRMOF-3, and CCDC for ZIF-8). A Quantachrome Autosorb-1C surface area and pore size analyzer was used for measuring N 2 isotherm at 77K. Samples were dried in vacuum (~ Torr) at room temperature for 12h before N 2 adsorption measurement. BET surface area was S8

9 calculated based on the N 2 adsorption data within a relative pressure range of P/P o = 0.02 ~ A Thermo Scientific Nicolet 6700 Fourier transform infrared spectrometer was used for analyzing MOF growth on IR silicon wafers. Dynamic light scattering (Zetasizer Nano, Malvern Instruments Ltd) was used to measure the size distribution of ZnO nanoslurries. Breakthrough Test for NH 3 and H 2 S The adsorption performance of our MOF-functionalized fiber mats was characterized with a custom-built rapid screening micro-breakthrough system. 1 Challenge gas (NH 3 or H 2 S in moisturized air, 1000 mg/m 3 concentration, 50% relative humidity) was injected into an adsorbent column loaded with MOF-fiber material (~20 mg). The column temperature was kept at 20 C in a water bath. The downstream concentration was analyzed with a continuously measuring gas chromatograph (HP5890 Series II) equipped with a photoionization detector for NH 3 (or a flame photometric detector for H 2 S). 5 Breakthrough Data Analysis Dynamic loading (DL in units of mol/kg) of challenge gas on MOF-functionalized fibers was calculated using the following equations. 5 N feed = C feedf feed t total M w (2) t total C out F feed N out = dt 0 M w (3) DL = N feed N out m ads (4) S9

10 N feed (mol) is the total moles of challenge gas injected into the adsorbent column, N out (mol) is the total moles of challenge gas detected in the downstream. C feed and C out (g/m 3 ) are the concentrations of challenge gas in the feed and the downstream respectively. F feed (m 3 /min) is the feed flow rate, t (min) is test time. M w (g/mol) is the molecular weight of the challenge gas, and m ads (kg) is the adsorbent mass. S10

11 Figure S1. Size distribution of ZnO nanoslurries dispersed in deionized water measured by dynamic light scattering (DLS). The average particle size is 252±23 nm, and the polydispersity index is S11

12 Figure S2. (a-b) SEM images of HKUST-1 crystals obtained from the rapid room-temperature synthesis. (c) Crystal size distribution analyzed from SEM images (100 measured data points). The average crystal size is 1.17±0.40 μm. S12

13 Figure S3. (a) SEM image of HKUST-1 crystals prepared via rapid synthesis (dispersed on a silicon wafer). (b-d) Energy dispersive X-ray (EDX) mapping images for C, O and Cu in the HKUST-1 crystals. (e) EDX spectrum showing that no Zn can be detected by EDX (blue dash lines indicate where Zn can be expected). S13

14 Figure S4. (a-c) ToF-SIMS surface mapping (negative ion mode) images for a layer of densely packed HKUST-1 crystals. These results confirm the presence of (a) oxygen, (b) carbon and (c) copper. (d) ToF-SIMS depth profile (positive ion mode) for C +, Cu + and 65 Cu + in a layer of densely packed HKUST-1 crystals. Zn-containing residue was not found by either positive or negative detection mode. S14

15 Table S1. ICP-OES for the concentration of Cu and Zn in the HKUST-1 crystals prepared through the rapid room-temperature MOF synthesis. n(zno):n(cu(no 3 ) 2 ) Reaction Cu Concentration * Zn Concentration n(zn):n(cu) Time (min) in MOF (wt%) in MOF (wt%) in MOF 1: :628 1: :67 2: :62 1: :45 *The difference of Cu concentration in the MOF is probably a result of solvent inclusion. Higher Cu concentration is observed for the samples completely activated after vacuum drying in a BET tube. Table S2. ICP-OES for the concentration of Cu and Zn in the filtrate after collecting the MOF powder by filtration. n(zno):n(cu(no 3 ) 2 ) Reaction Cu Concentration Zn Concentration n(zn):n(cu) Time (min) in filtrate * (wt%) in filtrate * (wt%) in filtrate 1: :2.3 1: :1.2 *The solvent was further evaporated from the filtrate. While the actual concentration of Cu 2+ and Zn 2+ both increased during solvent removal, the ratio (n(zn):n(cu)) did not change in the concentrated filtrate assuming Cu 2+ and Zn 2+ are not volatile. ICP-OES analysis for the filtrate collected after synthesis shows that Zn 2+ concentration in the filtrate is at least one order of magnitude greater than that in the MOF powder, and that n(zn):n(cu) in the filtrate is larger than the initial molar ratio in the mixed reactants. These results can be explained by the conversion of ZnO to (Zn,Cu) HDS and the release of Zn-containing species into the solution during the HDS-to-MOF conversion. S15

16 Figure S5. N 2 adsorption and desorption isotherm for the HKUST-1 powder prepared via rapid synthesis. S16

17 Figure S6. SEM images for HKUST-1 grown on top of (Zn,Cu) hydroxy double salt. S17

18 Figure S7. Powder XRD pattern for the Cu-BDC MOF converted from (Zn,Cu) hydroxy nitrate HDS at room temperature (red). The simulated Cu-BDC pattern is shown in black. The XRD pattern of the Cu-BDC obtained from HDS agrees well with the simulated pattern and reported powder XRD patterns for this MOF. 6,7 The results from the synthesis of HKUST-1 and Cu-BDC from (Zn,Cu) HDS indicate that (Zn,Cu) hydroxy nitrate is an intermediate that preferentially converts to Cu-based MOFs. S18

19 Intensity (a.u.) (Zn,Zn) hydroxy acetate HDS IRMOF-3 converted from (Zn,Zn) HDS (111) (200) (311) (220) (222) (400) (420) (511) (440) (600) (531) (620) (533) (444) (711) (642) (731) Simulated IRMOF-3 Pattern (733) (751) (753) degree) Figure S8. Powder XRD patterns for the (Zn,Zn) HDS (blue) and IRMOF-3 converted from (Zn,Zn) HDS at room temperature (red). The simulated IRMOF-3 pattern is shown in black. S19

20 Intensity (a.u.) (Zn,Zn) Hydroxy Acetate HDS ZIF-8 Converted from (Zn,Zn) HDS (110) (200) (211) (220) (310) (222) (321) (411) (332) Simulated ZIF-8 Pattern (degree) Figure S9. Powder XRD patterns for the (Zn,Zn) hydroxy acetate HDS synthesized with DMF (blue) and ZIF-8 converted from (Zn,Zn) HDS (red). The simulated ZIF-8 pattern is shown in black. S20

21 Figure S10. (a) Photo of circular and star-shape HKUST-1 patterns. The red box in (a) represents the location of Image (b). (b-d) Optical micrograph and SEM images of star patterns made from HKUST-1. The red box in (c) shows the location of (d). S21

22 Figure S11. SEM images for (a) untreated PS microspheres, (b) PS microspheres with ALD ZnO coating, and (c-d) HKUST-1 grown on ZnO-coated PS microspheres. S22

23 Figure S12. (a-c) SEM images for ZnO-coated PP fibers (a) before and (b-c) after HKUST-1 rapid synthesis. Insert photo in (b) shows the macroscopic uniformity of MOF growth on the PP fiber mat. (d) Cross-sectional TEM image shows uniform HKUST-1 coating on ZnO-coated PP fibers. (e-f), SEM images for ZnO-coated PAN nanofibers (e) before and (f) after HKUST-1 rapid synthesis. Insert optical image in (f) shows the uniform MOF growth on the PAN nanofiber mat. S23

24 Figure S13. (a) XRD patterns for ALD ZnO coated polypropylene fiber mat (PP/ZnO, red) and HKUST-1 grown on PP/ZnO (MOF-PP, blue). (b) XRD patterns for ALD ZnO coated PAN nanofiber mat (PAN/ZnO, red) and HKUST-1 grown on PAN/ZnO (MOF-PAN, blue) S24

25 Figure S14. (a) NH 3 breakthrough curves for untreated PP and MOF-PP fiber mats. (b) H 2 S breakthrough curves for untreated PP and MOF-PP fiber mats. (c) NH 3 breakthrough curves for untreated PAN and MOF-PAN fiber mats. 1. Morioka, H.; Tagaya, H.; Karasu, M.; Kadokawa, J.; Chiba, K. Inorg. Chem. 1999, 38, Zhao, J.; Gong, B.; Nunn, W. T.; Lemaire, P. C.; Stevens, E. C.; Sidi, F. I.; Williams, P. S.; Oldham, C. J.; Walls, H. J.; Shepherd, S. D.; Browe, M. A.; Peterson, G. W.; Losego, M. D.; Parsons, G. N. J. Mater. Chem. A 2015, 3, Gotthardt, M. A.; Schoch, R.; Wolf, S.; Bauer, M.; Kleist, W. Dalton Trans. 2015, 44, Wong-Foy, A. G.; Matzger, A. J.; Yaghi, O. M. J. Am. Chem. Soc. 2006, 128, Glover, T. G.; Peterson, G. W.; Schindler, B. J.; Britt, D.; Yaghi, O. M. Chem. Eng. Sci. 2011, 66, Carson, C. G.; Hardcastle, K.; Schwartz, J.; Liu, X.; Hoffmann, C.; Gerhardt, R. A.; Tannenbaum, R. Eur. J. Inorg. Chem. 2009, 2009, Rodenas, T.; Luz, I.; Prieto, G.; Seoane, B.; Miro, H.; Corma, A.; Kapteijn, F.; Llabrés i Xamena, F. X.; Gascon, J. Nat. Mater. 2015, 14, 48. S25