Supporting Information

Transcription

1 Supporting Information Insights into CO 2 and CH 4 Adsorption by Pristine and Aromatic Amine- Modified Periodic Mesoporous Phenylene-Silicas Mirtha A. O. Lourenço, a Christophe Siquet, b,* João Santos, b Miguel Jorge, c José R. B. Gomes, d Paula Ferreira a,* a CICECO, Departament of Materials and Ceramic Engineering, University of Aveiro, Campus Universitário de Santiago, Aveiro, Portugal. b LSRE, Faculty of Engineering, University of Porto, Rua Dr. Roberto Frias, s/n, Porto, Portugal. c Department of Chemical and Process Engineering, University of Strathclyde, 75 Montrose Street, Glasgow G1 1XJ, United Kingdom. d CICECO, Department of Chemistry, University of Aveiro, Campus Universitário de Santiago, Aveiro, Portugal. Corresponding Authors* Phone: ; fax: ; addresses: csiquet@fe.up.pt (C. Siquet); pcferreira@ua.pt (P. Ferreira) S1

2 Contents 1. Experimental 2. Characterization of PMO materials Figure and Table Captions Figure S1. Manometric apparatus. Val: valve, PT: pressure sensors (P1-4), TS: temperature sensors (T1-5). Figure S2. Sample activation: heating program used in this work. Figure S ºC nitrogen adsorption-desorption isotherms of C n -PMOs and NH 2 -C n - PMOs. Figure S4. TEM images of NH 2 -C n -PMOs. Figure S5. 13 C CP-MAS NMR spectra of C n -PMOs and NH 2 -C n -PMOs. Table S1. Percentage of T m silanols species calculated from the fits of the 29 Si MAS NMR spectra. Figure S6. FTIR (ATR) spectra of C n -PMOs and NH 2 -C n -PMOs. Table S2. Elemental analyses of C n -PMOs and NH 2 -C n -PMOs. Figure S7. TGA C n -PMOs and NH 2 -C n -PMOs materials. Figure S8. Adsorption equilibrium isotherms of pure CO 2 and CH 4 molecules in the C n - PMOs and NH 2 -C n -PMOs. Figure S9. Correlation between the percentage of T 2 silanols species presented on the material and the Henry constant of CO 2 on a) C n -PMOs and b) NH 2 -C n -PMOs. S2

3 1. Experimental Characterization Transmission electron microscopy (TEM) images were made by a 200 kv High Resolution (HR) and energy-filtered (EF) TEM JEOL 2200FS Instrument. Powder X-ray diffraction (PXRD) data were collected with a Rigaku Geigerflex D Max-C Series diffractometer using Cu-Kα radiation. Samples were step-scanned in 0.02º 2θ steps with a counting time of 3 s per step. Nitrogen adsorption-desorption isotherms were measured at -196 ºC using a Gemini V 2.00 instrument model All PMO materials were dehydrated overnight at 200 ºC to an ultimate pressure of 1024 mbar and then cooled to room temperature prior to adsorption. 13 C, 29 Si and 15 N NMR spectra were obtained using a double resonance MAS probe on a Bruker Avance III 400 spectrometer operating at 9.4 T. 13 C cross-polarization magic-angle spinning (CP MAS) NMR spectra were recorded with 4 µs 1 H 90º pulse, a contact time (CT) of 1.5 ms a spinning rate of 7 and 9 khz and recycle delay (RD) of 5 s. 29 Si MAS NMR spectra were acquired employing 40º flip angle pulses, a spinning rate of 5.0 khz, and RD of 60 s. Despite being a quantitative technique, the acquisition of spectra with acceptable signal to noise ratio, requires long time. 29 Si CP MAS NMR spectra were acquired with 4 µs 1 H 90º pulses, a CT of 8 ms, a spinning rate of 5 khz, and a RD of 5 s. The 29 Si CP MAS NMR is just a qualitative technique because it involves the transference of polarization between 1 H and 29 Si nuclei. The spectra are obtained in a short period of time with improved signal to noise ratio, being very useful to clearly identify the chemical environments to be quantified in the 29 Si MAS NMR spectra. 15 N CP MAS NMR spectra were achieved using a 4 µs 1 H 90º flip angle pulse, a CT of 8 ms, a spinning rate of 5 khz and a RD of 5 s. The 13 C and 29 Si NMR spectra were quoted in ppm from trimethylsilane, while 15 N NMR spectra were referenced against a solid sample of natural abundance L-glycine, a secondary reference standard with respect to nitromethane. Thermogravimetric analyses (TGA) were made on a Shimadzu TGA-50 instrument with a program rate of 5 ºC min -1 in air. S3

4 Fourier transform infrared (FTIR) spectroscopies were done in a FTIR Bruker Tensor 27 instrument with a Golden Gate ATR (Attenuated Total Reflectance). PMO powders were dehydrated at 110 ºC overnight before FTIR analysis. The FTIR spectra were recorded in Absorbance mode. Elemental analyses CHN were realized with a TruSpec CNHS Analyser. Analysis Parameters: sample amount between 1 and 2 mg; combustion furnace temperature = 1075 ºC; afterburner temperature = 850 ºC. Detection method: carbon -infrared absorption; hydrogen - infrared absorption, nitrogen thermal conductivity. Experimental Apparatus. The custom made manometric experimental setup shown in Figure S1 is composed of two gas and sample chambers allowing the analysis of two adsorbents simultaneously. Pressure and temperature are monitored and valves are controlled by a personal computer running a custom made LabVIEW program. All valves are from ASCO (Emerson) and are pneumatic actuated. Valves 2 and 4 are normally opened valves (ref. E290A794) while the remaining are normally closed (ref. E290A791). Valves 1 and 3 enable the introduction of the gas (from Gas Inlet) or evacuation of the system (towards the atmosphere, through valve 6, or towards the vacuum pump, through valve 7). Valves Val 2 and 4 allow the isolation of the samples of adsorbent in the sample tanks when feeding or evacuating the gas tanks. The oven used for adsorbents activation and temperature control is a GC 1000 from Dani (Dani Instruments Spa, Milan, Italy). Temperature sensors TS are PT-100 Resistance Temperature Detector probe (type PR M MI-B) from Omega (Omega Engineering Ltd, Manchester, United Kingdom). Stainless steel tubing, tanks and fittings are from Swagelok. The pressure transducers PS (Unik 5000, PMP 5013-TB-A3-CA-HO-PA, bar (A) and 0-10 bar (B), absolute) from GE are used to follow the pressure inside the tanks along the experiment. The volume of the gas tanks (volume between valves 1 and 2) is 73.4 cm 3 and 71.3 cm 3, and the volume of the sample tanks (including free volume of the tubes until valves 2 and S4

5 4) is of 24.8 cm 3 and 26.4 cm 3 for unit 1 and 2, respectively. These volumes were determined by two independent helium picnometry experiments. Figure S1. Manometric apparatus. Val: valve, PT: pressure sensors (P1-4), TS: temperature sensors (T1-5). Sample activation min Temperature ( C) min 0.2 C/min 0.2 C/min Time (h) Figure S2. Sample activation: heating program used in this work. 2. Characterization of PMO materials S5

6 Figure S ºC N 2 isotherms of synthesized PMOs. The squares represent the unmodified PMOs and the spheres represent aminated PMOs. The open symbols denote adsorption and the filled symbols characterize desorption. The insets display the PSD curves of all used materials where the continuous black line corresponds to C n -PMOs and the dashed grey line corresponds to the NH 2 -C n -PMOs. S6

7 Figure S4a. High-resolution transmission electron microscopy image of NH2-C12-PMO, NH2-C14-PMO NH2-C16-PMO and NH2-C18-PMO, materials. Figure S4b. TEM image of the edge on of the NH2-C16-PMO. S7

8 Figure S5. 13 C CP-MAS NMR spectra of a) C n -PMOs and b) NH 2 -C n -PMOs. The spectrum of NH 2 -C 18 -PMO was collected with a spinning rate of 7 khz. The spectra of the other materials were recorded with a spinning rate of 9 khz. S8

9 Table S1. T m species in the prepared materials calculated from the fits of the 29 Si MAS NMR spectra. Materials SiO 2 OH a (%) SiO(OH) 2 b (%) T 1 NMR c (%) T 2 NMR d (%) Condensation degree e (%) T 1 SMP f (%) T 2 SMP g (%) C 12 -PMO NH 2 -C 12 -PMO C 14 -PMO NH 2 -C 14 -PMO C 16 -PMO NH2-C 16 PMO C 18 -PMO NH 2 -C 18 -PMO a Percentage of single T 2 type silanol regarding to the hydroxylated silanols calculated as T 2 /(T 1 +T 2 ), where the T 1 and T 2 are the area of the resonances at ca. -61 and -71 ppm, respectively. b Percentage of geminal T 1 type silanol regarding to the hydroxylated silanols calculated as T1/(T 1 +T 2 ). c Percentage of germinal T 1 type silanol regarding to all silicon species calculated as T 1 /(T 1 +T 2 +T 3 ) where the T 1, T 2 and T 3 are the area of the resonances at ca. -61, -71 and -81 ppm, respectively, obtained from the deconvolution of peaks from the fits of the 29 Si MAS NMR spectra. d Percentage of the total T 2 type silanol regarding to all silicon species calculated as T 2 /(T 1 +T 2 +T 3 ). e Percentage of the condensation degree that correspond to the percentage of T 3 type silicon species regarding to all silicon types calculated as T 3 /(T 1 +T 2 +T 3 ). f Percentage of germinal T 1 type silanol presented in the material regarding to all silicon species calculated as (T 1 /(T 1 +T 2 +T 3 )) x % Si-O. g Percentage of total T 2 type silanol presented in the material regarding to all silicon species calculated as (T 2 /(T 1 +T 2 +T 3 )) x % Si-O. S9

10 Figure S6. FTIR (ATR) spectra of a) C n -PMOs and b) NH 2 -C n -PMOs. S10

11 Weight / % Weight / % CSérie1 12 -PMO NH Série2 2 -C 12 -PMO Temperature / C CSérie1 14 -PMO NH Série2 2 -C 14 -PMO Temperature / C Weight / % Weight % CSérie1 16 -PMO NH Série2 2 -C 16 -PMO Temperature / C CPMO 18 -PMO NH2-PMO 2 -C 18 -PMO Temperature / C Figure S7. TGA C n -PMOs and NH 2 -C n -PMOs materials. S11

12 Table S2. Elemental analyses and nitrogen density of C n -PMOs and NH 2 -C n -PMOs. Sample % N % C a % H % Si-O b N density / mmol g -1 % phenylene moieties aminated C 12 -PMO NH 2 -C 12 -PMO C 14 -PMO NH 2 -C 14 -PMO C 16 -PMO NH 2 -C 16 PMO C 18 -PMO NH 2 -C 18 -PMO a Note that the %C of carbon for the non-aminated samples can be theoretically calculated using the T m function of % T 3, % T 2, and % T 1 silicon species in the pure C n -PMO material. In this way, based on the molecular formula of organosilicas SiO 1.5 -R-SiO 1.5, the percentage of carbon can be calculated as %C = [3 At.Wt. C / (1.5 At.Wt. O + 1 At.Wt. Si + 3 At.Wt. C + 2 At.Wt. H )] % T 3 + [3 At.Wt. C / (2 At.Wt. O + 1 At.Wt. Si + 3 At.Wt. C + 3 At.Wt. H )] % T 2 + [3 At.Wt. C / (2.5 At.Wt. O + 1 At.Wt. Si + 3 At.Wt. C + 3 At.Wt. H )] % T 1, where At.Wt. stands for the atomic weights of the elements and % T 3, % T 2 and % T 1 are the percentages of T m silanol species reported in Table S2. For instance, in the case of the C 12 - PMO material, the formula above gives %C = [ / ( )] [ / ( )] [ / ( )] 2.02 = %. The % C for the remaining samples are %, % and %, respectively for C 14 -PMO, C 16 -PMO and C 18 -PMO. The maximum difference observed between theoretical and experimental %C is 2.35 % for C 16 -PMO. The good qualitative agreement supports the consideration of the % T 3, % T 2 and % T 1 for providing a quantitative measurement of the T m environments in each sample, which is essential to support the function described by equation 2. b The percentage of Si-O was determined by the equation % Si-O = 100 % - % C - % H - % N. S12

13 Figure S8. Adsorption equilibrium isotherms of pure CO 2 (closed symbols) and CH 4 (open symbols) molecules in the as-synthesized (squares) and amine functionalized (spheres) C n - PMOs. Solid lines represent the fits to Langmuir model. Table S3. Langmuir parameters of C n -PMOs and NH 2 -C n -PMOs for de CO 2. Sample qs (mol kg -1 ) b (bar -1 ) C 12 -PMO NH 2 -C 12 -PMO C 14 -PMO NH 2 -C 14 -PMO C 16 -PMO NH 2 -C 16 PMO C 18 -PMO NH 2 -C 18 -PMO S13

14 Figure S9. Correlation between the percentage of T 2 SMP silanols species presented on the material and the Henry constant of CO 2 on a) C n -PMOs and b) NH 2 -C n -PMOs. S14