Supplementary Information

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1 Supplementary Information Stable aluminum metal-organic frameworks (Al-MOFs) for balanced CO 2 and water selectivity Haiwei Li, Xiao Feng, * Dou Ma, Mengxi Zhang, Yuanyuan Zhang, Yi Liu, Jinwei Zhang, and Bo Wang * Key Laboratory of Cluster Science, Ministry of Education of China, School of Chemistry and Chemical Engineering, Beijing Institute of Technology, 5 South Zhongguancun Street, Beijing , P. R. China. * bowang@bit.edu.cn; fengxiao86@bit.edu.cn Contents Section A. Materials and methods Section B. Experimental section Section C. Crystal structure and supplementary spectra Section D. Supporting references S-1

2 Section A. Materials and method All reagents and starting materials were obtained commercially and were used as received without any further purification. 2-hydrox-1,4-benzendicarboxylicacid (OH-BDC), 2-methyl-1,4-benzendicarboxylicacid (CH 3 -BDC) and 2,5-dimethyl-1,4-benzendicarboxylicacid [(CH 3 ) 2 -BDC] were purchased from Chemsoon Co., Ltd., 2-amino-1,4-benzendicarboxylicacid (NH 2 -BDC) and AlCl 3 6H 2 O were bought from Energy Chemical. DMF and methanol were purchased from Beijing Chemical Works. Powder X-ray diffraction (PXRD) patterns of the samples were recorded on a Bruker Focus D8 diffractometer with Cu-Kα X-ray radiation (λ = nm). The attenuated total reflection Fourier-transform infrared (ATR-FTIR) spectra were recorded in the range cm -1 on Bruker ALPHA spectrometer. N 2 sorption isotherms were measured at 77 K on a Quantachrome Instrument ASiQMVH002-5 after pretreatment (samples were degassed at 150 C for 10 h). The pore size distributions were estimated using nonlocal density functional theory (NLDFT) with N 2-77 K isotherm curves. CO 2 and H 2 O sorption isotherms were measured on the same instrument after pretreatment. Elemental analyses (C, H, N) were obtained using EuroEA Elemental Analyser. Al content was determined by a PLASMA-SPEC (I) ICP atomic emission spectrometer. The thermogravimetric analysis (TGA) of samples was performed on a PerkinElmer STA6000 Simultaneous Thermal Analyzers with a constant heating rate of 10 C min -1 under air in a temperature range from r.t. to 800 C. S-2

3 Section B. Synthetic procedures Preparation of MOFs (a) Synthesis of CAU-1: CAU-1 was synthesized according to the reported literature 1 with slight modification. AlCl 3 6H 2 O (93.0 mg, mmol) and NH 2 -BDC (23.3 mg, mmol) were dissolved in 1.25 ml of methanol in a 4 ml jar with a teflon lined lid. The reaction mixture was heated in an oven at 125 C for 5 h to yield yellow microcrystalline powder. After centrifugation, the remaining solid was stirred in 100 ml deionized water to remove chloride ions, and then washed three times with 500 ml of anhydrous DMF. After that, the product was soaked in CHCl 3 for 3 days with fresh solvent exchanged every 24 h. Finally, the solvent was decanted and the included CHCl 3 was removed under vacuum to give the product CAU-1. (b) Synthesis of BIT-72: AlCl 3 6H 2 O (93.0 mg, mmol) and 2-hydrox-1,4-benzendicarboxylicacid (23.5 mg, mmol) were dissolved in 1.25 ml of methanol in a 4 ml jar with a teflon lined lid. The reaction mixture was heated in an oven at 125 C for 5 h to yield white microcrystalline powder. After centrifugation, the remaining solid was first stirred in deionized water (500 ml per 0.5 g) to remove chloride ions, and then washed three times with 500 ml of anhydrous DMF. After that, the product was soaked in CHCl 3 for 3 days with fresh solvent exchanged every 24 h. Finally, the solvent was decanted and the included CHCl 3 was removed under vacuum to give the product BIT-72. (c) Synthesis of BIT-73: S-3

4 AlCl 3 6H 2 O (93.0 mg, mmol) and 2-methyl-1,4-benzendicarboxylicacid (23.2 mg, mmol) were dissolved in 1.25 ml of methanol in a 4 ml jar with a teflon lined lid. The reaction mixture was heated in an oven at 125 C for 5 h to yield white microcrystalline powder. After centrifugation, the remaining solid was first stirred in deionized water (500 ml per 0.5 g) to remove chloride ions, and then washed three times with 500 ml of anhydrous DMF. After that, the product was soaked in CHCl 3 for 3 days with fresh solvent exchanged every 24 h. Finally, the solvent was decanted and the included CHCl 3 was removed under vacuum to give the product BIT-73. (d) Synthesis of BIT-74: AlCl 3 6H 2 O (98.0 mg, mmol) and 2,5-dimethyl-1,4-benzendicarboxylicacid (26.0 mg, mmol) were dissolved in 1.25 ml of methanol in a 4 ml jar with a teflon lined lid. The reaction mixture was heated in an oven at 125 C for 5 h to yield white microcrystalline powder. After centrifugation, the remaining solid was first stirred in deionized water (500 ml per 0.5 g) to remove chloride ions, and then washed three times with 500 ml of anhydrous DMF. After that, the product was soaked in CHCl 3 for 3 days with fresh solvent exchanged every 24 h. Finally, the solvent was decanted and the included CHCl 3 was removed under vacuum to give the product BIT-74. S-4

5 Section C: Crystal structure and supplementary spectra Figure S1. The crystalline structure of two cages of BIT-72/73/74. In the crystals of BIT-72/73/74, four 8-rings secondary building units (SBUs) form the tetrahedral cage while the octahedral cage is formed by six SBUs. S-5

6 Figure S2. FT-IR spectra of NH 2 -BDC (black) and CAU-1 (red) S-6

7 Figure S3. FT-IR spectra of OH-BDC (black) and BIT-72 (red) S-7

8 Figure S4. FT-IR spectra of CH 3 -BDC (black) and BIT-73 (red) S-8

9 Figure S5. FT-IR spectra of (CH 3 ) 2 -BDC (black) and BIT-74 (red) S-9

10 Table S1. Elemental analysis and inductively-coupled plasma emission spectroscopy (ICP) results Materials Experimental value (wt%) Calculated value (wt%) C H N Al C H N Al CAU BIT BIT BIT S-10

11 Figure S6. TGA curve of CAU-1 under air with a heating rate of 5 K/min S-11

12 Figure S7. TGA curve of BIT-72 under air with a heating rate of 5 K/min S-12

13 Figure S8. TGA curve of BIT-73 under air with a heating rate of 5 K/min S-13

14 Figure S9. TGA curve of BIT-74 under air with a heating rate of 5 K/min S-14

15 Figure S10. Pore size distribution curves of CAU-1 (red), BIT-72 (pink), BIT-73 (navy) and BIT-74 (violet) based on NLDFT from N 2-77 K isotherms S-15

16 Table S2. Data from N 2-77 K isotherm curves Materials 1 S BET V total V mico PSD 2 (m 2 g -1 ) (cm 3 g -1 ) (cm 3 g -1 ) (nm) CAU , 0.86 BIT , 0.86 BIT , 0.86 BIT , : Calculated with the point at P/P 0 = : Pore size distribution based on nonlocal density functional theory (NLDFT) method. S-16

17 Table S3. CO 2 uptake of several selected water stable MOFs at 273 K and 1 bar Materials CO 2 uptake (cm 3 g -1 ) Reference BIT in this work BIT in this work BIT in this work In 2 (OH)(btc)(Hbtc) 0.4 (L) 0.6 3H 2 O 75 Inorg. Chem., 2016, 55, PCP Inorg. Chem., 2015, 54, Bio-MOF Chem. Sci., 2013, 4, Bio-MOF Chem. Sci., 2013, 4, Bio-MOF Chem. Sci., 2013, 4, Ni-4PyC 123 Sci. Adv., 2015, 1:e ZIF Science, 2008, 319, UiO Chem. Eur. J., 2015, 21, MIL-125(Ti) 99 Angew. Chem. Int. Ed., 2012, 51, NH 2 -MIL-125(Ti) 132 Angew. Chem. Int. Ed., 2012, 51, MIL-101(Cr) 75 New J. Chem., 2016,40, PCN J. Am. Chem. Soc., 2015, 137, ZIF-8 37 RSC Adv., 2015, 5, MIL-53(Al) 76 Fuel, 2012, 102, NU J. Am. Chem. Soc., 2013, 135, S-17

18 Figure S11. CO K isotherm curves of CAU-1 S-18

19 Figure S12. CO K isotherm curves of BIT-72 S-19

20 Figure S13. CO K isotherm curves of BIT-73 S-20

21 Figure S14. CO K isotherm curves of BIT-74 S-21

22 Figure S15. N K isotherm curves of CAU-1 (red), BIT-72 (blue), BIT-73 (pink) and BIT-74 (navy) S-22

23 Figure S16. PXRD patterns of CAU-1 simulated (black line), CAU-1 as-synthesized (orange line), after treatment of H 2 O at r.t. for 3 days (blue line), 100 C H 2 O for one hour (green line) and ph = 4 at r.t. for 3 days (pink line) S-23

24 Figure S17. PXRD patterns of CAU-1 simulated (black line), BIT-72 (red line), BIT-73 (blue line), BIT-74 (green line) and CAU-1 as synthesized (pink line) after treatment of ph = 9 basic aqueous at r.t. for 3 days. The good stability of BIT-72/73/74 can be explained by the hard/soft acid-base principle where Al 3+ ions act as hard acid while oxygen donors on carboxylate ligands act as hard base. Thus, relative strong bonds are formed between Al 3+ and carboxylate ligands in these Al-MOFs and lead to good stability in water, acidic and basic conditions. S-24

25 Ideal adsorbed solution theory (IAST) selectivity calculations: Ideal Adsorbed Solution Theory (IAST) of Myers and Prausnitz along with the pure component isotherm fits was applied to determine the molar loadings in the gas mixture for specified partial pressures in the bulk gas phase. The pure component isotherms of CO 2 measured were fitted with the dual-site Langmuir (DSL) model: The pure component isotherms of N 2 measured were fitted with the single-site Langmuir (SSL) model: where q is molar loading of adsorbate (mmol g 1 ), q sat is saturation loading (mmol g 1 ), b is parameter in the pure component Langmuir isotherm (bar 1 ), p is bulk gas phase pressure (bar). Pure-component isotherm fitting parameters were then used for calculating IAST binary-gas adsorption selectivities (S ads ). S ads is defined as: S-25

26 Figure S18. H 2 O-283 K isotherm curves of CAU-1 S-26

27 Figure S19. H 2 O-283 K isotherm curves of BIT-72 S-27

28 Figure S20. H 2 O-283 K isotherm curves of BIT-73 S-28

29 Figure S21. H 2 O-283 K isotherm curves of BIT-74 S-29

30 Section D. Supporting references 1. T. Ahnfeldt, N. Guillou, D. Gunzelmann, I. Margiolaki, T. Loiseau, G. Férey, J. Senker and N. Stock, Angew. Chem. Int. Ed., 2009, 48, S-30