Supporting Information High-throughput Computational Screening of the MOF Database for CH 4 /H 2 Separations Cigdem Altintas, a Ilknur Erucar b and Seda Keskin a* a Department of Chemical and Biological Engineering, Koc University, Rumelifeneri Yolu, Sariyer, 34450, Istanbul, Turkey b Department of Natural and Mathematical Sciences, Faculty of Engineering, Ozyegin University, Cekmekoy, 3474, Istanbul, Turkey *Corresponding author. Email: skeskin@ku.edu.tr, Phone: +0 (212) 338-1362 Submitted to ACS Applied Materials & Interfaces S-1
35 σ H2 σ CH4 30 25 LCD (Å) 20 15 10 5 0 5 10 15 20 25 30 35 PLD (Å) Figure S1. Pore limiting diameters (PLD) and the largest cavity diameters (LCD) of MOFs. Red lines show the kinetic diameters of the H 2 and CH 4 molecules. S-2
S acc (m 2 /g) 7500 6000 4500 3000 LCD ( Å ) 4.0 6.0 8.0 12.0 18.0 33.7 1500 0 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0. 1.0 Figure S2. Porosities and accessible surface areas of MOFs, color-coded according to their largest cavity diameters. φ S-3
10 Gas uptake (mmol/g) 1 0.1 0.01 closed symbols: simulations open symbols: experiments 0.001 0.1 1 10 100 Pressure (bar) CH4 uptake at 28 K IRMOF-1 CuBTC UiO-66 ZIF-8 H2 uptake at 77 K IRMOF-1 CuBTC UiO-66 H 2 uptake at 28 K ZIF-8 Figure S3. Comparison of the adsorption isotherms of CH 4 and H 2 in some prototypical MOFs, IRMOF-1, CuBTC, UiO-66 and ZIF-8. Experimental data for adsorption isotherms of IRMOF-1, 1-2 CuBTC, 3-4 UiO-66 5-6 and ZIF-8 7-8 were taken from the literature. S-4
1.0 (a) 1 bar 0.8 0.6 R 2 0.4 0.2 0.0 S acc LCD φ 1/ AD Q 0 st 1.0 (b) 10 bar 0.8 0.6 R 2 0.4 0.2 0.0 S acc LCD φ Q 0 st 1/ AD Figure S4. R 2 values showing the relation between selectivity and several parameters calculated at (a) 1 bar (b) 10 bar. S-5
Table S1. Interaction potential parameters used for gas molecules Molecule σ (Å) ε/k B (K) H 2 2.6 34.20 CH 4 3.73 148.20 Table S2. Comparison of our simulated adsorption isotherms with the experimental data for CH 4 and H 2 in various MOFs. MOF Pressure and temperature Gas References IRMOF-1 1-30 bar, 28 K CH 4 IRMOF-8 0-50 bar, 28 K CH 4 PCN-14 0-1600 bar, 28 K CH 4 NU-125 0-60 bar, 28 K CH 4 Bio-MOF-11 10-4 -1 bar, 77-87 K H 2 Zn(bdc)(ted) 0.5 0-40 bar, 28 K CH 4 COF-5, COF-6, COF-10 0-50 bar, 77 K H 2 MMIF 0-1 bar, 15 K CH 4 ZIF-8 0.1-10 bar, 28 K CH 4 ZIF-68, ZIF-6 0-1 bar, 273 K CH 4, H 2 PCN-26 0-1 bar, 77, 87, 15, 28 K CH 4, H 2 PCN-6, PCN-6', PCN-10, PCN-11, PCN-14, PCN-16, PCN-20, PCN-26, PCN-46, PCN-80 PCN-11, PCN-14, PCN-16, PCN-26, PCN- 46, PCN-80 1-50 bar, 77, 87, 150, 28 K H 2 1-65 bar, 26, 28, 300 K CH 4 10 11 12 13 8 14 15 16 16 Table S3. Coefficients of the model used to predict selectivity of MOFs: S b ads = a (1/ AD) + c Coefficient Value a 645.14 b -2.70 c 0.17 d -1.58 ( LCD) d S-6
References (1) Rowsell, J. L. C.; Millward, A. R.; Park, K. S.; Yaghi, O. M., Hydrogen Sorption in Functionalized Metal-Organic Frameworks. J. Am. Chem. Soc. 2004, 126 (18), 5666-5667. (2) Pillai, R. S.; Pinto, M. L.; Pires, J.; Jorge, M.; Gomes, J. R., Understanding gas adsorption selectivity in IRMOF-8 using molecular simulation. ACS Appl. Mater. Interfaces 2015, 7 (1), 624-637. (3) Liang, Z.; Marshall, M.; Chaffee, A. L., CO 2 adsorption-based separation by metal organic framework (Cu-BTC) versus zeolite (13X). Energy Fuels 200, 23 (5), 2785-278. (4) Liu, J.; Culp, J. T.; Natesakhawat, S.; Bockrath, B. C.; Zande, B.; Sankar, S.; Garberoglio, G.; Johnson, J. K., Experimental and theoretical studies of gas adsorption in Cu 3 (BTC) 2: an effective activation procedure. J. Phys. Chem. C 2007, 111 (26), 305-313. (5) Chavan, S.; Vitillo, J. G.; Gianolio, D.; Zavorotynska, O.; Civalleri, B.; Jakobsen, S.; Nilsen, M. H.; Valenzano, L.; Lamberti, C.; Lillerud, K. P., H 2 storage in isostructural UiO-67 and UiO-66 MOFs. Phys. Chem. Chem. Phys. 2012, 14 (5), 1614-1626. (6) Abid, H. R.; Pham, G. H.; Ang, H.-M.; Tade, M. O.; Wang, S., Adsorption of CH 4 and CO 2 on Zr-metal organic frameworks. J. Colloid Interface Sci. 2012, 366 (1), 120-124. (7) Voskuilen, T. G.; Pourpoint, T. L.; Dailly, A. M., Hydrogen adsorption on microporous materials at ambient temperatures and pressures up to 50 MPa. Adsorption 2012, 18 (3-4), 23-24. (8) Kinik, F. P.; Altintas, C.; Balci, V.; Koyuturk, B.; Uzun, A.; Keskin, S., [BMIM][PF 6 ] Incorporation Doubles CO 2 Selectivity of ZIF-8: Elucidation of Interactions and Their Consequences on Performance. ACS Appl. Mater. Interfaces 2016, 8 (45), 302-31005. () Altintas, C.; Keskin, S., Computational screening of MOFs for C 2 H 6 /C 2 H 4 and C 2 H 6 /CH 4 separations. Chem. Eng. Sci. 2016, 13, 4-60. (10) Atci, E.; Erucar, I.; S., K., Adsorption and Transport of CH 4, CO 2, H 2 Mixtures in a Bio-MOF Material from Molecular Simulations. J. Phys. Chem. C 2011, 115 (14), 6833-6840. (11) Erucar, I.; Keskin, S., Separation of CO 2 Mixtures Using Zn(bdc)(ted) 0.5 Membranes and Composites: A Molecular Simulation Study. J. Phys. Chem. C 2011, 115 (28), 13637-13644. (12) Keskin, S., Adsorption, Diffusion, and Separation of CH 4 /H 2 Mixtures in Covalent Organic Frameworks: Molecular Simulations and Theoretical Predictions. J. Phys. Chem. C 2011, 116 (2), 1772-177. (13) Keskin, S., High CO 2 Selectivity of A Microporous Metal-Imidazolate Framework: A Molecular Simulation Study. Ind. Eng. Chem. Res. 2011, 50 (13), 8230-8236. (14) Ozcan, A.; Keskin, S., Effects of Molecular Simulation Parameters on Predicting Gas Separation Performance of ZIFs. J. Chem. Technol. Biotechnol. 2014, 0 (), 1707 1718. (15) Ozturk, T. N.; Keskin, S., Predicting Gas Separation Performances of Porous Coordination Networks Using Atomistic Simulations. Ind. Eng. Chem. Res. 2013, 52 (4), 17627-1763. (16) Ozturk, T. N.; Keskin, S., Computational Screening of Porous Coordination Networks for Adsorption and Membrane-Based Gas Separations. J. Phys. Chem. C 2014, 118 (25), 1388-137. S-7