Supporting Information Co-adsorption and Separation of CO -CH 4 Mixtures in the Highly Flexible MIL-53(Cr) MOF. Lomig Hamon, a Philip Llewellyn, b,* Thomas Devic, c Aziz Ghoufi, d Guillaume Clet, e Vincent Guillerm, c Gerhard Pirngruber, a,* Guillaume Maurin, d Christian Serre, c Gordon Driver, b Wouter Van Beek, f,g Elsa Jolimaître, a Alexandre Vimont, e Marco Daturi, e and Gérard Férey c a IFP, Direction Catalyse et Séparation, rond-point de l'échangeur de Solaize, 6936 Solaize, France, b Laboratoire Chimie Provence, UMR CNRS 664 Universités d'aix-marseille I, II & III, Centre de Saint Jérôme, 3397 Marseille cedex, France, c Institut Lavoisier, UMR CNRS 88 Université de Versailles St Quentin en Yvelines, 45 avenue des Etats-Unis, 7835 Versailles, France, d Institut Charles Gerhardt, UMR 553 CNRS UM ENSCM, Université de Montpellier II, Place E. Bataillon, 3495 Montpellier cedex 5, France, e Laboratoire Catalyse et Spectrochimie, ENSICAEN, Université de Caen Basse Normandie, CNRS, 6 boulevard du Maréchal Juin, 45 Caen, France, f SNBL at ESRF, rue Jules Horowitz, 3843 Grenoble, France, g Dipartimento di Scienze e Tecnologie Avanzate, Università del Piemonte Orientale A. Avogadro, 5 Alessandria, Italy *To whom correspondence should be addressed. Phone: +33 478 733. Fax: +33 478 66. E- mail: philip.llewellyn@univ-provence.fr; gerhard.pirngruber@ifp.fr; S
Experimental details Details of the analysis of the Raman spectra. Raman spectra were recorded in the 885-7 cm - region for CO and the bands of the framework and in the 56-3 cm - domain for CH 4. Semi-quantitative data were obtained from the integrated intensities of characteristic bands of the adsorbed gases, the ν band at ~383 cm - for CO and the ν band at ~96 cm - for CH 4. Structural bands of the MIL-53 occurring in the same region were used as internal reference (at ~4 cm - for CO and ~37 cm - for CH 4 ). To enable comparison, a correction coefficient of 4.7 was applied to the bands of CH 4, resulting from the ratio between the bands of CH 4 and CO gases (for a given pressure in our conditions A(CH 4 )/A(CO ) ~5.9) and the ratio between the structure bands at ~4 cm - and ~37 cm - which did not change notably (A(4)/A(37) ~.8). This correction factor is based on the assumption that the Raman scattering cross sections are not significantly different in the gas and adsorbed phases. Similar assumptions have been followed in the case of confined gases in the cages of clathrates. 4 Typical Raman spectra of CO and CH 4 in gas phase and adsorbed on MIL-53(Cr) are shown in Figure S. Intensity (a.u.) CO CH 4 5 5 3 35 4 45 Raman shift (cm - ) 88 9 96 3 34 38 Raman shift (cm - ) Figure S. Raman spectra of the pure gases (blue) CO and CH 4 and the adsorbed species on MIL53(Cr) (red)..in order to determine the NP/LP fractions, spectra were curve-fitted in the 45-475 cm - region with three bands at 48-434, 443-445, 456-46 cm - (see Figure S3) using 85% Lorentzian + 5% Gaussian bands which showed the best fitting. FWHMs (Full Width at Half Maximum) were kept between 8 and. Spectra of samples constituted solely NP (upon hydration) or LP forms (upon high S
pressure of CO or outgassed at 473 K) were used to estimate the relative Raman cross-sections of the two bands characteristics of each structural version. The band at 444 cm - obtained for the pure LP form was found in average 3. larger than the one observed at 43 cm - for the pure NP version. The fraction of the NP form in the solid was thus determined from the relative intensities of these two bands after correction with the latter factor. Experimental details of the breakthrough curve measurements. Breakthrough curve experiments were carried out with a column with a length of 8 cm and an internal diameter of.5 cm, packed with sample powder. The column was placed into an oven and was outgassed at 473 K with a helium flow of NL. h -. The same CO -CH 4 gas mixtures as for the gravimetric measurements were prepared via mass flow controllers (pure gases provided by Air Liquide). Breakthrough experiments were performed by switching abruptly from He to CO -CH 4 mixtures (unless otherwise noted). The adsorbed amounts of CO and CH 4 were calculated by mass balances. Breakthrough experiments were carried out at pressures up to. MPa at 33 K with flow ranges from.5 to 4 NL. h -. In the Figures, breakthrough curves are represented in the form of the normalized flow rates F i /F i,, F i being the measured flow rate of component i at the column outlet and F i, being the feed flow rate of component i. Figure S shows a scheme of the setup used for the breakthrough experiments at high pressure. Different gas mixtures can be prepared by a set of mass flow controllers. The gas mixture is either sent to the adsorption column, which is placed in an oven, or to a bypass line. A backpressure regulator is placed downstream of the column and fixes the pressure in the column and by-pass line. Downstream of the backpressure regulator, the column effluent is diluted with helium and is then analyzed by a mass spectrometer. The dilution is necessary since the response of the mass spectrometer is linear only in a concentration range of 5%. The dilution brings the concentrations of the eluted gases down to this range. Moreover, it keeps the total flow rate more or less constant, which is a necessary condition for obtaining correct mass balances. S3
helium for dilution pure CH 4 or binary mixture CO/CH 4 V by pass mass spectrometer event pure CO inert gas (helium) column oven V Figure S. Scheme of the setup used for breakthrough experiments. In practice, the experiment is conducted as follows: The column is filled with adsorbent (here in the form of powder) and placed in the oven. The adsorbent is activated in flow of. NL. h - of helium at a temperature of 473 K. After keeping that temperature for the desired amount of time, the oven is brought back to the temperature of the breakthrough experiment. The pressure is raised to the desired level and the flow of helium used for the downstream dilution is switched on ( NL. h - ). The column is then isolated by turning the two valves up-stream and down-stream of the column (as shown in the in Figure), i.e. it remains filled with helium at the pressure of the experiment. The gas mixture to be used for the breakthrough experiments is then prepared. Total flow is fixed at 4. nl. h - for all adsorption experiments. It flows via the by-pass line to the mass spectrometer. Once the mass spectrometer signals of the feed mixture have been stabilised the breakthrough experiment is started by turning the valves V and V. The raw breakthrough curves therefore have the following appearance: At the beginning, i.e. before turning valve V, the mass spectrometer detects the feed mixture. Once the feed is directed to the S4
column by turning valve V it pushes the helium that was left in the column. The concentration of the other components decreases and only helium is detected in the mass spectrometer until breakthrough of the first component occurs. It is important to take into account the dead time when determining breakthrough time: this dead time corresponds to the gas crossing from V to the column and from the outlet of the column to the mass spectrometer. The knowledge of these volumes allows a determination of the dead time as a function of flow. In order to fully regenerate the column for the next procedure the initial activation procedure is repeated between each breakthrough experiment. The mass of the dry adsorbent is determined at the end of a series of experiments. Supplementary results Unit cell parameters and cell volumes of MIL-53(Cr) during co-adsorption of CO /CH 4 mixtures Table S. Pores opening (large pore / narrow pore forms) and cells parameters of MIL-53(Cr) upon adsorption of CO -CH 4 mixtures. CO -CH 4 mixture P (bar) State a (Å) b (Å) c (Å) β ( ) V (Å 3 ) 5-75 Lp 6.78(7) 3.4(6) 6.83() 9 5.() 3. Lp 6.384(9) 3.5886(9) 6.835(3) 9 5.7() 5-5 Lp 6.753(4) 3.74(3) 6.8335() 9 5.64(6). lp + np 6.7985(5) 3.493(5) 6.8338() 9 498.(9) 9.7() 8.3943(5) 6.863(6) 6.7() 8.() 7.8 lp + np 6.73(8) 3.676(6) 6.8334(3) 9 53.6() 9.74() 8.53(4) 6.869(6) 6.33(8) 94.5() 5.4 Lp 6.458(4) 3.575(4) 6.8385() 9 5.5(6) 75-5 Lp 6.7459(7) 3.9(6) 6.836(3) 9 499.8().7 lp + np 6.788() 3.56() 6.83(5) 9 497.5() 9.695(5) 8.45() 6.87() 6.(3) 8.6(4) S5
7. lp + np 6.678() 3.() 6.8357(7) 9 55.(3) 9.683(3) 8.49(9) 6.84() 6.4() 9.8(3) 7.4 Lp 6.3998(8) 3.5776(7) 6.839(3) 9 5.8() Determination of the LP/NP fraction by deconvolution of the Raman spectra (a) (b) LP form Mixture NP/LP NP form 4 43 45 47 Raman shift (cm - ) fraction of NP.8.6.4...5.5.5 pressure (MPa) Figure S3. Fraction of the NP form as calculated from Raman results.(a) Raman spectra of ν sym (COO) depending on the crystallographic phase ; (b) Gas feed CO -CH 4 : / (*), 75-5( ), 5-5 ( ), and 5-75 ( ). S6
(a) 4 (b) adsorbed amount (mg/g) 3 adsorbed amount (mg/g) pressure (MPa) 3 pressure (MPa) (c) 3 adsorbed amount (mg/g) 3 pressure (MPa) Figure S4. Adsorption (blue diamonds) and desorption (red circles) isotherms at 33 K on the MIL- 53(Cr): (a) pure CO, (b) 5-75 CO -CH 4 mixture, (c) 75-5 CO -CH 4 mixture. Breakthrough curves of CO -CH 4 mixtures adsorption on the MIL-53(Cr) S7
(a) F/F.6..8.4 3 4 (b) F/F.6..8.4 3 4 (c) F/F.6..8.4 3 4 Figure S5. Breakthrough curve of binary CO -CH 4 mixtures on MIL-53(Cr) at 33 K and. MPa: CO in red, CH 4 in blue. Gas feed CO -CH 4 : (a) 5-75, (b) 5-5, and (c) 75-5. S8
(a).5 F/F.5.5 5 (b).5 F/F.5.5 5 (c).5 F/F.5.5 5 Figure S6. Breakthrough curve of binary CO -CH 4 mixtures on MIL-53(Cr) at 33 K and.5 MPa: CO in red, CH 4 in blue. Gas feed CO -CH 4 : (a) 5-75, (b) 5-5, and (c) 75-5. S9
(a) F/F.6..8.4 5 5 (b) F/F.6..8.4 5 5 (c) F/F.6..8.4 5 5 Figure S7. Adsorption of CO -CH 4 binary mixture on MIL-53(Cr) at 33 K and. MPa: CO in red, CH 4 in blue. (a): 5% mol. CO, 75% mol. CH 4 ; (b): 5% mol. CO, 5% mol. CH 4 ; (c): 75% mol. CO, 5% mol. CH 4. S
a) b) SM intensity (a.u.).e-6.e-7.e-8.e-9 44 amu 5 amu volumetric flow rate (nl/h) 3.5 3.5.5.5 CO CH4.E- 5 5 5 5 Figure S8. a) Raw mass spectrometer signal of mass 44 (CO ) and mass 5 (CH 4 ). b) Calculated molar flow rates of CO and CH 4 at the column exit in nl/h. The chosen example corresponds to the adsorption of equimolar CO /CH 4 mixture at. MPa..8 fraction of NP.6.4...4.6.8 CO mole fraction in gas phase Figure S9. NP fraction as a function of the CO mole fraction in gas phase at. MPa (+),. MPa ( ),.5 MPa ( ),. MPa ( ), and. MPa ( ). S