Preparation and properties of metal organic framework/ activated. carbon composite materials

Transcription

1 Preparation and properties of metal organic framework/ activated carbon composite materials Ohad Fleker, Arie Borenstein, Ronit Lavi, Laurent Benisvy, Sharon Ruthstein, and Doron Aurbach * The Chemistry Department, Faculty of Exact Sciences, Bar Ilan University, Ramat-Gan, Israel, * Corresponding author: Doron.Aurbach@biu.ac.il These authors contributed equally to this work. Supplementary Information HKUST-1 synthesis Figure S1. Synthesis procedure of HKUST-1 MOF. Mil-100(Fe) synthesis Mil-100(Fe)@AC composite material (a) was prepared by suspending 240 mg of oven-dried AC into a 10 ml H 2 O solution of H 3 BTC (90 mg, 4.26x10-4 mol) in a 50 ml flask. The suspension was stirred while heating to 45 C for 2 hr. Then, Fe(acac) 3 (150 mg, 4.26x10-4 mol, 1 eq. with respect to H 3 BTC) was added and the mixture was stirred for an additional 2 hr at 45 C. A condenser was fitted to the reaction flask and the mixture was heated to reflux at 95 C overnight. The

2 resulting suspension was then centrifuged, decanted, and the solid was washed with 15 ml of H 2 O. These washing cycles of centrifuging and decanting were repeated 3 times. The resulting solid was dried on a hot-plate. Compositions (b) and (c) were prepared according to the same procedure, using 59.7 mg and 44.7 mg of H 3 BTC, respectively, and appropriate quantities of Fe(acac)3 (1 eq) and of AC. The resulting Mil-100(Fe)@AC compositions (a)-(c) contain 25% (a), 16.7% (b), and 12.5% (c) of Mil-100(Fe) by weight. The prepared compounds were stored in open air. Figure S2. Synthesis procedure of Mil-100(Fe) MOF. Activated Carbon (AC) characterization Raman spectroscopy Raman spectroscopy of the activated carbon show typical pattern in which the 'D band' at Raman shift of 1300 cm -1 is a little lalger than the 'G band' at Raman shift of 1600 cm -1. That means that the activated carbon has an overall amorphous structure with local nano structure of graphite.

3 D G Figure S3. Raman spectroscopy of the activated carbon used in this study, with typical peaks related to graphitic (G) and disordered carbon (D) structures. CHONS elemental analysis CHONS elemental analysis was conduct to ensure the purification of the activated carbon used in the synthesis of the composite material. The result shows clean carbon with only small amount of H and O atoms, probably related to water adsorbed on the surface of the carbon. Before the synthesis process we dried the AC at 120 C for 12 hours to ensure the dryness of the carbon. Table S1: CHONS analysis of the activated carbon used in this study. Element Containment, % C 96.6% H 1.2% O 2.0%

4 Powder XRD (PXRD) (a) Figure S4. PXRD data comparison. Pristine AC (blue), pristine HKUST-1 (red), Composite 3 (black), composite 2 (pink), and composite 1 (cyan). (b) Mil-100(Fe)@AC Mil-100(Fe) PXRD spectra is characterized by signals at 5-25, with the most intense signals monitored between the angles of 10 to 12. Following activation the synthesized Mil-100(Fe) powder display signals at the regions of 10 15, and between 17 21, parallel to several major signals of the crystal structure, in accordance to previously reported data. 1 Both the synthesized pristine powder sample, and composition sample display a characteristic signal between angles of 10-11, associated with the most intense signal of the MOF compound.

5 Figure S5. Mil-100(Fe) PXRD data comparison to the simulated pattern using the Mil-100(Fe) crystal structure (orange), activated Mil-100(Fe) powder (green), and activated Composite a (blue). A signal at 11 is monitored for both the pristine and the composite samples. SEM Figure S6. SEM images of high resolution of C3 displaying carbon particles with no trace for copper on the outside of the particles.

6 TGA Figure S7. TGA plot for AC in nitrogen atmosphere, displaying its high thermal stability. BET isotherms Figure S8. BET isotherms for AC and composite 2. Some degree of a stepwise behavior is monitored for composite 2, typical for a multilayer adsorption on a uniform non-porous surface.

7 While composite 2 maintains a relative high surface area (SSA of 1170 m 2 /gr), this behavior may suggest that some of the material's pores have been completely blocked. 2 EPR Room temperature analysis for the native HKUST-1 broad spectrum (Figure 5a) gave g iso value of 2.19, comparable to reported parameters (e.g., 2.164). 3 HKUST-1 measured at 150K gave a resolved signal (Figure 5b), associated with two copper species, having an overall g iso value of Species A has a major influence (62%) with g xx = g yy = 2.13, g zz = 2.37, A xx = A yy = 10G, A zz = 163 G, and an overall g iso value of Species B, of a minor influence (38%) has g xx = g yy =2.08, g zz =2.353, A xx = A yy =20 G, and A zz = 163 G, with an overall g iso of Analysis of composite 2 yielded a resolved signal even at room temperature (Figure 5c), with g xx =g yy =2.074, g zz =2.338, A xx =A yy =15 G, A zz =160 G and an overall g iso value of Analysis of composite 2 at 150K (Figure 5d) resolved two species: Species A with g xx =g yy =2.075, g zz =2.325, A xx =A yy =10 G, A zz =168 G, with g iso =2.16. Species B with g xx = g yy = 2.135, g zz = 2.35, A xx = A yy = 20G, A zz = 168 G, and an overall g iso value of All parameters obtained fit a 4O coordination associated with a copper oxalate binding site. 4 Table S2. Room temperature EPR data, extracted using Easyspin simulation package. 5 (A,B,C corresponds to the different Cu(II) species. Sample g xx g yy g xx g iso A xx A yy A zz A ref cm cm cm -1 B ref D = cm -1 HKUST-1 C ref Ref cm cm cm -1 A cm cm cm -1 B cm cm cm -1 Composite 2 A cm cm cm -1 B cm cm cm -1

8 For comparison reasons, EPR signals of the pristine AC, and of a Cu(OAc) composition is presented in Figure S9. The composition was prepared by identical conditions used to prepare compositions 1-3, but using only the Cu(OAc) 2 H 2 O salt. We compared adsorption of the copper salt into AC using either a DMF or an aqueous solution. Interestingly, copper adsorption into the AC using a DMF solution was only moderate compared to adsorption from an aqueous solution. This effect was not monitored for the HKUST-1@AC compositions. Figure S9. EPR measurements at room temperature of pristine AC (a) and of the composite Cu(OAc)2@AC, adsorbed into the AC pores either from a DMF solution (b, green), or from an aqueous solution (b, orange). The EPR signal of mixture of AC and HKUST-1 consists of the signals of the two materials (Figure S10). This is in contrast to EPR signal of the HKUST-1@AC composition which is not similar to any of the signals of the two separate materials (Fig. 5 in the MS), thereby emphasizing the difference between only mixed MOF and AC (where MOF particles are located outside of AC particles), to MOF prepared inside the AC porous matrix. Note that thanks to the spin dilution effect of the AC matrix, the signal associated with the HKUST-1 MOF in the mixture has a smaller line width (measured as line width at half max, LWHM) compared to the pristine HKUST-1 MOF sample.

9 Figure S10. EPR signals from measurements at room temperature of pristine AC (black), HKUST- 1 (blue), and of a mixture of AC and HKUST-1, containing 16.7% of HKUST-1 by weight (green). Electrochemical measurements Figure S11. Electrical conductivity of pellet samples of AC, Mil-100(Fe), and compositions a-c.

10 For comparison reasons, typical cyclic-voltammogram of the pristine AC is presented in Figure S12. Figure S12. Cyclic voltammograms of AC in a 3 electrode cell. The electrolyte was 1.4M (TEA)BF 4 in Propylene carbonate. Scan rate was 10 mv/s. The reference electrode was a silver wire. 110 F/g Figure S13. Cyclic voltammograms of Mil-100(Fe)@AC in a 3 electrode cell (A), and 2 electrode supercapacitor cell (B). The electrolyte was 1.4M (TEA)BF 4 in Propylene carbonate. Scan rate was 10 mv/s. The reference electrode in A was gold wire.

11 124 F/g Figure S14. Cyclic voltammogram of Full supercapacitors cell comprising of composite 2 (HKUST- 1@AC, 1:2 ratio) as anode and weight-balanced unmodified AC as cathode. The electrolyte was 1.4M (TEA)BF 4 in Propylene carbonate. Scan rate was 10 mv/s. References (1) Zhang, F.; Shi, J.; Jin, Y.; Fu, Y.; Zhong, Y.; Zhu, W. Facile Synthesis of MIL-100(Fe) under HF- Free Conditions and Its Application in the Acetalization of Aldehydes with Diols. Chem. Eng. J. 2015, 259, (2) Sing, K. S. W. Reporting Physisorption Data for Gas/solid Systems with Special Reference to the Determination of Surface Area and Porosity (Recommendations 1984). Pure Appl. Chem. 1985, 57 (4), (3) Pöppl, A.; Kunz, S.; Himsl, D.; Hartmann, M. CW and Pulsed ESR Spectroscopy of Cupric Ions in the Metal Organic Framework Compound Cu3(BTC)2. J. Phys. Chem. C 2008, 112 (7), (4) Peisach, J.; Blumberg, W. E. Structural Implications Derived from the Analysis of Electron Paramagnetic Resonance Spectra of Natural and Artificial Copper Proteins. Arch. Biochem. Biophys. 1974, 165 (2), (5) Stoll, S.; Schweiger, A. EasySpin, a Comprehensive Software Package for Spectral Simulation and Analysis in EPR. J. Magn. Reson. 2006, 178 (1), (6) Gul-E-Noor, F.; Jee, B.; Mendt, M.; Himsl, D.; Pöppl, A.; Hartmann, M.; Haase, J.; Krautscheid, H.; Bertmer, M. Formation of Mixed Metal Cu3 xznx(btc)2 Frameworks with Different Zinc Contents: Incorporation of Zn2+ into the Metal Organic Framework Structure as Studied by Solid-State NMR. J. Phys. Chem. C 2012, 116 (39),