Supporting information Interaction of Acid Gases SO, NO with Coordinatively Unsaturated Metal Organic Frameworks: M-MOF-74 (M= Zn, Mg, Ni, Co) Kui Tan 1, Sebastian Zuluaga, Hao Wang 3, Pieremanuele Canepa,3, Karim Soliman, Jeremy Cure 1, Jing Li 4, Timo Thonhauser,5, and Yves J. Chabal 1 1 Department of Materials Science & Engineering, University of Texas at Dallas, Richardson, Texas 75080, USA Department of Physics, Wake Forest University, Winston-Salem, NC 7109, USA 3 Materials Science Division, Lawrence Berkeley National Laboratory, Berkeley, CA 9470, USA 4 Department of Chemistry and Chemical Biology, Rutgers University, Piscataway, New Jersey 08854, USA 5 Department of Chemistry, Massachusetts Institute of Technology, Cambridge, MA, 0139, USA 1. Sample preparation and activation Zn-MOF-74: A mixture of zinc nitrate hexahydrate (0.4 g, 0.8 mmol),, 5- dihydroxyterephthalic (0.08 g, 0.4 mmol), 9 ml DMF and 1 ml H O were transferred into a 8 ml Teflon-lined autoclave. The autoclave was then sealed and heated to 10 C for 3 days. After filtering and washing with 0 ml DMF, the product was collected. Then the product was exchanged with 0 ml methanol in a glass vial every hs during daytime for 3 days. Mg-MOF-74: A mixture of magnesium nitrate hexahydrate (0.6 g, 1 mmol),, 5- dihydroxyterephthalic (0.1 g, 0.5 mmol), 7 ml tetrahydrofuran (THF), 3 ml water H O and ml 1 M NaOH solution was prepared in a 8 ml Teflon-lined autoclave. The autoclave was then sealed and heated to 100 C for 3 days. After filtering and washing with 0 ml THF, the product was collected and exchanged with methanol every hs during daytime for 3 days. Then the MOFs sample was stored in N glove box. Ni-MOF-74: A mixture of nickel nitrate hexahydrate (0.4 g, 0.8 mmol),, 5- dihydroxyterephthalic (0.08 g, 0.4 mmol), 9 ml DMF and 1 ml H O was prepared in a 8 ml Teflon-lined autoclave. The autoclave was then sealed and heated to 100 C for 3 days. After filtering and washing with 0 ml DMF, the product was collected and exchanged with methanol every hs during daytime for 3 days. Then the MOFs sample was stored in N glove box. Co-MOF-74: A mixture of cobalt nitrate hexahydrate (0.17 g, 0.6 mmol),, 5- dihydroxyterephthalic (0.06 g, 0.3 mmol), 9 ml DMF and 1 ml H O was prepared in a 8 ml Teflon-lined autoclave. The autoclave was then sealed and heated to 100 C for 3 days. After filtering and washing with 0 ml DMF, the product was collected and exchanged with methanol every hs during daytime for 3 days. Then the MOFs sample was stored in N glove box. The crystal structures of the three MOF-74 samples (Zn, Mg, Co, Ni) were measured by PXRD and compared to the simulated PXRD pattern of Ni-MOF-74 in reference 1, as shown in Figure
S. The XRD diffraction patterns of the samples we studied are in agreement with literature reports. The BET surface areas of the three compounds are measured by N isotherm. The values for Zn-, Mg-, Ni-, and Co-MOF-74 are 774, 1078, 913, and 1077 m /g, respectively. Table S1 summarize the values measured in this work and those measured in previous literature reports. Note that there have been many studies of MOF-74 with some variations in the activation processes, resulting in a range of BET surface areas. Clearly, the activation of MOF-74 structure containing coordinatively unsaturated metal sites is not as easy as for other MOFs such as M(bdc)(ted) 0.5. We used the same synthetic method with modified and more thorough solvent exchange. As a result, the values of surface areas for our sample MOF74-Co/Ni/Mg/Zn are in the range reported in the literature. The spectroscopic study of this work focuses on the interaction or reaction mechanism of acid SO, NO with available open metal sites. The interpretation derived from the results will therefore not be influenced if a small fraction of other metal sites are not open for adsorption because of possible incomplete activation.
Table S1. Summary of BET surface areas of M-MOF-74 (M= Mg, Co, Ni, Zn), compared with values reported in previous studies. M=Mg, Co, Ni BET surface area (m /g) Ref. Mg-MOF-74 1495 3 154 4 1530 5 155 6 1415 7 106 8 1174 9 1174 10 877 11 1078 This work Co-MOF-74 1080 3 19 5 1089 7 957 1 835 8 1077 This work Ni-MOF-74 1083 1 1199 5 1018 7 88 10 936 1 639 13 913 This work Zn-MOF-74 816 3 867 14 496 15 774 This work
Absorbance Absorbance Absorbance Absorbance. IR spectra of activated MOFs a 0.1 Zn- MOF-74 b 0.05 Mg- MOF-74 3500 3000 500 000 1500 1000 3500 3000 500 000 1500 1000 c 0. Ni- MOF-74 d 0. Co- MOF-74 3500 3000 500 000 1500 1000 3500 3000 500 000 1500 1000 Figure S1. IR adsorption spectra of activated MOF-74 samples referenced to pure KBr in vacuum.
Intensity (a.u.) aintensity (a.u.) Zn-MOF-74 Mg-MOF-74 (10) (300) 5 10 15 0 5 30 35 theta b Co-MOF-74 (10) Ni-MOF-74 (300) 5 10 15 0 5 30 35 40 theta A Figure S. Power X-ray diffraction patterns of Zn, Mg, Ni, Co-MOF-74 samples after both NO and SO exposures, measured right after the IR measurements and compared to as-synthesized and activated samples.
SO uptake mmol/g 3. Isotherm of SO in Mg-MOF-74 9 8 7 6 5 4 3 1 0.0 0. 0.4 0.6 0.8 1.0 1. Pressure (bar) Figure S3. SO adsorption and desorption isotherms of Mg-MOF-74 performed at room temperature. Filled and open symbols represent adsorption and desorption, respectively. References: 1. Dietzel, P. D. C.; Johnsen, R. E.; Fjellvag, H.; Bordiga, S.; Groppo, E.; Chavan, S.; Blom, R., Adsorption properties and structure of CO adsorbed on open coordination sites of metal-organic framework Ni (dhtp) from gas adsorption, IR spectroscopy and X-ray diffraction. Chemical Communications 008, (41), 515-517.. Lee, J. Y.; Olson, D. H.; Pan, L.; Emge, T. J.; Li, J., Microporous Metal Organic Frameworks with High Gas Sorption and Separation Capacity. Advanced Functional Materials 007, 17, (8), 155-16. 3. Caskey, S. R.; Wong-Foy, A. G.; Matzger, A. J., Dramatic Tuning of Carbon Dioxide Uptake via Metal Substitution in a Coordination Polymer with Cylindrical Pores. Journal of the American Chemical Society 008, 130, (33), 10870-10871. 4. Dietzel, P. D. C.; Besikiotis, V.; Blom, R., Application of metal-organic frameworks with coordinatively unsaturated metal sites in storage and separation of methane and carbon dioxide. Journal of Materials Chemistry 009, 19, (39), 736-7370. 5. Perry, J. J.; Teich-McGoldrick, S. L.; Meek, S. T.; Greathouse, J. A.; Haranczyk, M.; Allendorf, M. D., Noble Gas Adsorption in Metal Organic Frameworks Containing Open Metal Sites. J. Phys. Chem. C. 014, 118, (), 11685-11698. 6. Yang, D.-A.; Cho, H.-Y.; Kim, J.; Yang, S.-T.; Ahn, W.-S., CO capture and conversion using Mg-MOF-74 prepared by a sonochemical method. Energy Environ. Sci. 01, 5, (4), 6465-6473.
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