Conception of hierarchical porous materials synthesized from single molecular precursors

Transcription

1 FUNDP (CMI) Arnaud Lemaire Conception of hierarchical porous materials synthesized from single molecular precursors Summary of the presentation I. Introduction II. bjectives & Strategies III. Macro-mesoporous Aluminosilicates IV. Highly ordered mesoporous Zirconosilicates V. Conclusions

2 CATALYSTS New materials Microporous ZELITHES : Acido-basic properties ~ Al--Si (Al T ) + H - Al Si Cristalline structures(stables) Strongacidicsites (Al T ) Porous: Ø< 1,5 nm (shapeselectivity), high accessible surface area (> 400 m²/g) Catalysts, adsorbants, molecular sieves, Ø< 1,5 nm coking, poisoning, limitation of diffusion Enlarge the PRE size with templates & sol-gel process

3 Zeolites Ø < 1.5 nm 2 < Ø < 50 nm Si Hexagonal array Sol-gel Hybrid material Pur Si2 material TEM Cross-section Extraction of surfactant 30 nm Amphiphilic molecules Zeolites Macroporous Ø < 1.5 nm 2 < Ø < 50 nm Ø > 50 nm

4 Zeolites Macroporous Ø < 1.5 nm 2 < Ø < 50 nm Ø > 50 nm Hierarchical Synthesis is difficult No scaling-up Removal of templating agent J.-L. Blin, A. Léonard, Z.-Y. Yuan,L. Gigot, A. Vantomme, A. K. Cheetham,B.-L. Su, Angew. Chem. Int. Ed., 2003, 42, 2872 X.-Y. Yang, Y. Li, A. Lemaire, J.-G. Yu, B.-L. Su, Pure Appl. Chem., 2009, 81, Zeolites Macroporous Ø < 1.5 nm 2 < Ø < 50 nm Ø > 50 nm Hierarchical Template-free hierarchical Auto-generation of hierarchical mulltiporosity Metal alkoxides M(R)n : Fast polymerization brutal release of porogen agents (RH/water) M(R)4 + H2 M2 (oxide) + RH (alcohol) A. Léonard, B.-L. Su, Chem. Commun., 2004, 1674 X.-Y. Yang, A. Léonard, A. Lemaire, G. Tian, B.-L. Su, Chem. Commun., 2011, DI : /C0CC03714F

5 Zeolites Ø< 1.5 nm 2 < Ø< 50 nm Hierarchical Macroporous Ø> 50 nm TEXTURAL PRPERTIES Template-free hierarchical 2 INDEPENDENTSprecursors Si(Me) 4 + Al(Bu) 3 : Al H - Si 1. Homopolymerisation Al(Bu) 3 + 3H 2 Al(H) 3 + 3BuH 2Al(H) 3 Al H 2 Extra-framework 2. Heteropolymerisation Zeolites Cristalline Al--Si frameworks Al(Bu ) 3 + Si(Me) 4 + 4H 2 CHEMICAL ACTIVITY Si/M >> Al T --Si + 3Bu H + 4MeH Intra-framework Multiporous Si 2 /M 2 Zeolites Ø< 1.5 nm 2 < Ø< 50 nm Hierarchical Macroporous Ø> 50 nm TEXTURAL PRPERTIES Template-free hierarchical Single molecular precursor (SMP) Hydrolysis Condensation SMP Homogeneous metallosilicates K. W. Terry, T. D. Tilley, Chem. Mater., 1991, 3, 1001 X.-Y. Yang, A. Vantomme, A. Lemaire, F.-S. Xiao, B.-L. Su, Adv. Mater., 2006, 18, 2117 CHEMICAL ACTIVITY Si/M ~ 1 Multiporous M--Si

6 BuH II. bjectives & Strategies SMP Al Si EtH Aqueous polymerization Reactives alkoxides = self-generation of macro-mesoporosities Al Materials H + - Si Macro-mesoporous aluminosilicate Si/Al ~ 1 Zr--Si t Bu t Bu t Bu Aqueous polymerization Petroleum cracking zirconosilicate materials Si/Zr ~ 4 4 Highly ordered Supramolecular assemblies Fine chemistry II. bjectives & Strategies SMP Rupture Strategies Materials Al H+ H Si 1/ Chelating agents 2/ Silica co-reactants Macro-mesoporous aluminosilicates Si/Al ~ 1 High reactivity Al 2 3 /Si 2 t Bu t Bu t Bu Si--Zr--H + H--Si reactivity H H H 3/ ph-adjusting step 4/ Templating agents zirconosilicate materials Si/Zr ~ 4 3 Zr 2 /Si 2

7 III. Macro-mesoporousaluminosilicates Si/Al ~ 1 1/ Chelating agents Amine ~ Sulfate < Phosphate < Carboxylate < β-diketones (acac) Chelating kpolym.si ~ kpolym.al Monodendate Bidendate I Bidendate II III. Macro-mesoporousaluminosilicates Si/Al ~ 1 27 Al MAS-NMR 29 Si MAS-NMR Intra-framework aluminium (Al--Si) 58.9 Technique Si/Al AAS 1.1 Si(Al)4 Si(Al) 3 Extra-framework aluminium (Al 2 3 ) =Si(Al) δ 27 Al (ppm) δ 29 Si (ppm)

8 III. Macro-mesoporous aluminosilicates Si/Al ~ 1 Polymerisation of (Bu)2-AlSi-(Et)3 : rapid release of BuH and EtH acting as «porogen» SEM III. Macro-mesoporous aluminosilicates Si/Al ~ 1 TEM SBET = 142 m²/g Volume poreux = 0,3 cm³/g dv/dd (cm³/g - nm) N2 Adsorbed volume (cm³/g - STP) 300 Calcination (600 C) Relative pressure (p/p ) Pore size distribution (nm)

9 V. Conclusions Conclusions 58.9 Al T (Al--Si) Si/Al = 1.1 Al Si 1/ Chelating agent δ 27 Al (ppm) Ø méso = 10 nm Double alkoxide= self-formation phenomenon of macro-mesoporosity A. Lemaire, B.-L. Su, Langmuir, 2010, 26, dv/dd (cm³/g - nm) 3-12 nm Simple, efficient and reproducible C Distribution de taille de pore (nm) dextran Adaptable (C 2, dextran) V. Conclusions Conclusions New stabilized alkoxy-bridged SMP Al Si SMP 2/ Silica co-reactants 1. Variable Si/Al ratios 2. Higher incorporation of Al 3. Modification of the reactivities

10 V. Conclusions SEM ph = 13,0 315 m²/g 70%AlT Si/Al = 1,5 TEM ph = 13,0 2 µm 200 nm ØMacro 50 nm ØMéso Less reactive new SMP Coalescence phenomenon ØMacro >> A. Lemaire, B.-L. Su, Microporous Mater. 2011, DI : /j.micromeso

11 ptical microscopy(m) V. Conclusions 100 µm 50 µm BuH EtH MeH H 2 10 µm A. Lemaire, B.-L. Su, Langmuir, 2011, DI : /la104679h V. Conclusions Conclusions 1200 Zr-Si 4-0,0(6,00%)S S BET = 641 m²/g 800 Volume poreux = 1,4 cm³/g Pression relative (p/p ) 0.5 6,0 nm Zr-Si 4-0,0(6,00%)S 4 Zr--Si t Bu t Bu t Bu SMP : tetrakis(tri-tert-butoxysiloxy) zirconium 4 4/ Templating agents Distribution de taille de pore (nm) 6,4 nm DRX Zr-Si 4-0,0(6,00%)S θ (degrees)

12 V. Conclusions Conclusions Zr--Si t Bu t Bu t Bu 4/ Templating agents SMP : tetrakis(tri-tert-butoxysiloxy) zirconium nm Highly ordered mesoporous zirconosilicates Conclusions V. Conclusions 20 nm Zr--Si t Bu t Bu t Bu Si/Zr = SMP : tetrakis(tri-tert-butoxysiloxy) zirconium 4 H H Zr-Si-D A. Lemaire, B.-L. Su, J. Colloid Interface Sci., submitted Quinone yields (%) Zr-Si-D Zr No catalyst TS Time (hours)

13 Thank you for your attention