Supporting information

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1 Supporting information CarbonateHydrogenocarbonate Coexistence and Dynamics in Layered Double Hydroxides Arnaud Di Bitetto a,b, Gwendal Kervern *,b, Erwan André a, Pierrick Durand b, and Cédric Carteret,a a Université de Lorraine, UMR 7564 (ULCNRS) LCPME, 405 rue de Vandœuvre, F VillerslèsNancy, France. b Université de Lorraine, UMR 7036 (ULCNRS) CRM2, BP Boulevard des Aiguillettes, F VandœuvrelèsNancy, France. * cedric.carteret@univlorraine.fr S1: Experimental and characterization details a) Chemical analysis calculi General formula: Mg II 1xAl III x(oh) 2 (A n ) x/n or Mg II RAl III (OH) 2(1+R) (CO 3 ) 1/2 where R = MII Considering the coexistence of carbonate and hydrogenocarbonate, that formula becomes: Mg II RAl III (OH) 2(1+R) ( ) y/2 (H ) 1y with y= CO 3 HCO 3 + CO 3 M III Thus [C] [Al] = 1 y 2 and y = 2 (1 [C] [Al] ) b) Mg II /Al III molar ratios and Water content and excl@mgal The amount of water in the samples was determined by weighting the samples before and after degassing 15h under vacuum at 100 C (10 4 Pa). Table S1. Mg II /Al III molar ratios and water content and excl@mgal. Mg II /Al III H Samples Theoretical Formula 2 O weight % z (H molar ratios g/g 2 Mg 2 Al(OH) 6 ( ) 0.5, z H 2 O Mg 3 Al(OH) 8 ( ) 0.5, z H 2 O Mg 4 Al(OH) 10 ( ) 0.5, z H 2 O excl@mgal2 Mg 2 Al(OH) 6 (Cl ) 1.0, z H 2 O excl@mgal3 Mg 3 Al(OH) 8 (Cl ) 1.0, z H 2 O excl@mgal4 Mg 4 Al(OH) 10 (Cl ) 1.0, z H 2 O S1

2 c) Details for 13 C exchange monitoring by Infrared spectroscopy HCO 3 1 mol/l CO 3 1 mol/l 13 C HCO 3 1 mol/l 13 C CO 3 1 mol/l Figure S1. Infrared ATR spectra of 13 C and carbonate and hydrogenocarbonate 1 mol/l solutions. Infrared reference spectra for 13 C and carbonate and hydrogenocarbonate, in the spectral range of the antisymmetric stretching vibrational modes, are presented in figure S1. Exchange kinetics of and (Mg II /Al III ratios of 2, 3 and 4) with atmospheric carbon dioxide (CO 2 ) was followed by collecting spectra at regular time intervals to follow the 13 C to conversion in the materials. The kinetics data (mixture spectra) were processed using the Bayesian positive source separation (BPSS) approach. This statistical approach addresses the mixture spectra decomposition using a Bayesian inference and gives a jointly estimation of the pure component spectra and the relative concentrations of the underlying species. Thus, it is possible to obtain a first approximation of the 13 C species concentration decay with time. For more details on this approach, the reader is redirected to the following references (the BPSS code may be kindly supplied to interested persons). (1) Moussaoui, S.; Carteret, C.; Brie, D.; MohammadDjafari, A. Bayesian Analysis of Spectral Mixture Data Using Markov Chain Monte Carlo Methods. Chemom. Intell. Lab. Syst. 2006, 81, (2) Moussaoui, S.; Brie, D.; MohammadDjafari, A.; Carteret, C. Separation of NonNegative Mixture of NonNegative Sources Using a Bayesian Approach and MCMC Sampling. IEEE Trans. Sig. Process. 2006, 54, (3) Dobigeon, N.; Moussaoui, S.; Tourneret, J. Y.; Carteret, C. Bayesian Separation of Spectral Sources Under Non Negativity and Full Additivity Constraints. Signal Process. 2009, 89, (4) Carteret, C.; Dandeu, A.; Moussaoui, S.; Muhr, H.; Humbert, B.; Plasari, E. Polymorphism Studied by Lattice Phonon Raman Spectroscopy and Statistical Mixture Analysis Method. Application to Calcium Carbonate Polymorphs during Batch Crystallization. Cryst. Growth Des. 2009, 9, S2

3 S2: Characterization, contact with air and H / quantification Table S2. Vibrational modes of and H in LDH @MgAl4) and in aqueous solutions (K 2, KH ). anion R2 LDH interlayer R3 LDH interlayer R4 LDH interlayer Aqueous Solution Assignment Infrared Raman Infrared Raman Infrared Raman Infrared Raman ν 4 (δ ) ν 2 (γ ) ν 1 (ν s ) ~1340 ~1350 ~ (ν a ) (ν a ) H anion R2 LDH interlayer R3 LDH interlayer R4 LDH interlayer Aqueous Solution Assignment Infrared Raman Infrared Raman Infrared Raman Infrared Raman γcoh δhoc δco γ 1025 (1016) νc OH δcoh ν s CO 2 (1620) ν a CO 2 Rudolph, W. W.; Irmer, G.; Königsberger, E. Speciation Studies in Aqueous H 2 Solutions. A Combined Raman Spectroscopic and Thermodynamic Study. Dalton Trans. 2008, S3

4 t = 8 weeks Figure S2. Contact with air followed by Raman spectroscopy for and H t = 8 weeks H Figure S3. Contact with air followed by Infrared spectroscopy for and S4

5 The Raman spectra in the same spectral range exhibited vibrational contributions very close to those observed for H / species in solution (Figure S4). Quantification for H / in the materials was made by measuring the area of each component and considering the ratio determined with solution reference data. The area ratio of hydrogenocarbonate on carbonate in the same concentration is of 1.5 (Rudolph, W. W.; Fischer, D; Irmer, G. Vibrational Spectroscopic Studies and density Functional Theory Calculations of Speciation in the CO 2 Water System. Appl. Spectrosc. 2006, 60, Rudolph, W. W.; Irmer, G.; Königsberger, E. Speciation Studies in Aqueous H 2 Solutions. A Combined Raman Spectroscopic and Thermodynamic Study. Dalton Trans. 2008, ). Raman intensity (a. u.) Figure S4. Raman spectra (H / region) of a) carbonate and hydrogenocarbonate 1 mol/l aqueous solutions, and after one week of contact with air, and their decomposition (experimental spectrum in circles, carbonate fit in dotted line, hydrogenocarbonate fit in dashed line, and complete fit in red line). S5

6 S3: Influence of cationic couples on H / detailed θ ( ) Figure S5. PXRD patterns for different Mg II /Ga III molar ratios. Table S3. Mg II /Ga III molar ratios Sample Mg II /Ga III molar Figure S6. Raman spectra after 1 week of contact with air for different Mg II /Ga III molar ratios. S6

7 @MgFe θ ( ) Figure S7. PXRD patterns for different Mg II /Fe III molar ratios. Table S4. Mg II /Fe III molar ratios Sample Mg II /Fe III molar @MgFe Figure S8. Raman spectra after 1 week of contact with air for different Mg II /Fe III (* = annex phase). molar ratios S7

8 S4: Influence of synthesis conditions on HCO 3 / detailed characterization (excl@mgal and ph=9 Intensity (a.u.) ph=10 ph= θ ( ) ph=9 Intensity (a.u.) ph=10 ph= θ ( ) ph=9 Intensity (a.u.) ph=10 ph= θ ( ) Figure S9. PXRD patterns excl@mgal and a) Mg II /Al III = 2, b) Mg II /Al III = 3 and c) Mg II /Al III = 4. S8

9 ph=9 ph= ph=9 ph= ph=9 ph= Figure S10. Infrared ATR spectra and a) Mg II /Al III = 2, b) Mg II /Al III = 3 and c) Mg II /Al III = 4. S9

10 Table S5. Mg II /Al III molar ratios and Samples Mg II /Al III molar ph= ph= ph= ph= ph= ph= ph= ph= ph= δ COH H H δ COH H H ph = 11 ph = 11 ph = 10 ph = 10 ph = 9 ph = 9 Figure S11. Infrared ATR spectra of at various exchange ph at a) and b) after contact with air. S10

11 H ph = 11 ph = 11 ph = 10 ph = 10 ph = 9 ph = 9 Figure S12. Infrared ATR spectra of a) and b) at various exchange ph before contact with air. S5: Contact with air followed by Raman spectroscopy for t = 8 weeks Figure S13. Contact with air followed by Raman spectroscopy for a) b) and c) S11

12 S6: Influence of cationic couples on 13 C conversion ( and Table S6. Mg II /M III molar ratios (M III = Ga III or Fe III ) for and Sample Mg II /M III molar ratio C H 13 C 13 C H 13 C t = 8 h t = 3 h t = 2 h t = 1 h t = 5 min 13 C H 13 C 13 C H 13 C (d) t = 8 h t = 3 h t = 2 h t = 1 h t = 5 min Figure S14. Contact with air followed by Infrared spectroscopy for a) b) c) and d) S12

13 S7: Solidstate NMR δ( 13 C)/ppm Figure S C CPMAS spectra at highspinning speed (12.5 khz) of for different Mg II /M III molar ratio (after about 15 minutes of contact with air). S8: CO 2 adsorption measurements CO 2 adsorption measurements were performed at 25 C with a BELSORPmax adsorption instrument (Bel Japan Inc). 100 mg of LDH were necessary, and samples were degassed before each measurement under vacuum at 100 C for 15h. Adsorbed Volume (ml/g STP) @MgAl2 Adsorbed Volume (ml/g STP) excl@mgal4 excl@mgal3 excl@mgal Pressure (kpa) Figure S16. CO 2 adsorption measurements for and b) excl@mgal Pressure (kpa) S13