Novel Synthesis and Activation strategies leading to the formation of tuned mesostructures

1. Novel Synthesis and Activation strategies leading to the formation of tuned mesostructures

2. Optimal Sorbent and Catalyst support requirements A. High adsorption capacity High number of active sites B. High selectivity: * pore volume * pore size distribution * surface area * surface composition C. Good kinetic properties: selection of * crystal size * particle size * porosity * binder type D. Good physical properties: * high bulk density * crush strenght * erosion resistance E. Good lifetime performance: * high chemical, thermal and mechanical stability

3. Mesoporous Templated Silicas General Introduction Mesoporous Templated Silicas (MTS) MCM- 41 MCM- 48 SBA-15 SBA-16 6 - 20 nm 2 - 6 nm PORE DIAMETER

4. Mesoporous Templated Silicas Typical Laboratory Synthesis Conditions Silica source Synthesis Characteristics Template pH Si/Templ. MCM-41 MCM-48 SBA-15 SBA-16 CTMABr Gem 16-8-16 Gem 16-12-16 Pluronic P123 EO20PO70EO20 Pluronic P127 EO106PO70EO106 13 13 <1 <1 TEOS/ Fumed silica TEOS/ Fumed silica TEOS TEOS 1/ 0.25 1/0.06 1/ 0.06 1/ 0.1 1/ 0.02 1/ 0.008 24 h at RT° + 2 days at 130°C in AC + 3 days HT 5 days at 130°C in AC + 3 days HT stirring 8 h at 45°C + ageing 16 h at 80°C stirring 8 h at RT° + ageing 16 h at 80°C CTMABr: Cetyltrimethylammonium bromide Gemini: [CmH2m+1(CH3)2N-CsH2s-N(CH3)2CnH2n+1]2Br

5. Mesoporous Templated Silicas Structural Characteristics MCM-41 MCM-48 SBA-15 SBA-16 Symmetry Surface Area (m²/g) Pore Volume (ml/g) Wall Thickness (nm) P6m (Hexagonal) 1000 1.2 1 Ia3d (Cubic) 1200 1.2 – 1.5 1 P6mm (2D Hexagonal) 700-1000 0.7 – 1.3 4 – 6 Im3m (Cubic) 700-900 0.4 – 0.8 5 – 8

6. Pore Size Engineering of MCM materials The effect of the synthesis conditions Influence of the chain length of the surfactant Addition of co-templates Tuning pore size distrubution

7. Pore Size Engineering MCM Synthesis Conditions Tuning of the pore size of the MCM material by selecting the synthesis conditions D A = 1 day base +1 day HT * r p = 1.0 nm B = 5 days base + 3 days HT r p = 1.2 nm C = 10 days base + 1 days HT r p = 1.3 nm D = 10 days base + 3 days HT r p = 1.5 nm C B A * HT = Hydrothermal treatment

8. Pore Size Engineering MCM Influence of the chain length Synthesis Conditions: 5 days at 130°C followed by hydro-thermal treatment of 3 days at 130°C Gem 18-12-18 Gem 16-12-16 Difference in surfactant side chain length Physical Properties: Gem 16-12-16 S BET = 1300 m2/g V P = 1.0 ml/g r P = 1.2 nm Gem 18-12-18 S BET = 1600 m2/g V P = 1.4 ml/g r P = 1.3 nm

9. co–template surfactant 0 0.6 0.3 1 1.2 1.8 Dimethylalkyl amines Gemini surfactants Pore Size Engineering MCM Addition of Co –Templates Enlargement of the pore size of MCM-48 due to the addition of dimethyl-hexadecyl amine as a swelling agent with different ratio of amine/surfactant. Other additives can be used like ethanol, decane and different dimethylalkyl amines. Ratio of Mechanism: Micelle

10. Morphologies of MCM Different morphologies: - fibers - layers - gyroids - rods -spheres - ….

11. Morphologies of MCM Hard spheres Hollow core spheres

12. Morphologies of MCM Hexagonal channels Cubic core

13. Catalytic Activation Overview Methods for catalytic activation in situ activation (during the synthesis) post-synthesis modification (after the synthesis) surface modification framework incorporation + surface modifiction various metal oxides (V, W, Ti, Cr, Mo, Al,…)

14. H C C H O 3 3 O O H C V C H ADSORPTION CALCINATION O O H C H C H 3 3 O Support Hydrogen Bonding Support-OH Support-O- VO + x H C O VO( acac ) 3 O 2 + Hacac H C V O O H C 3 Support Ligand Exchange Catalytic Activation Surface Modification The Molecular Designed Dispersion VO(acac)2 : Vanadylacetylacetonate

15. Si-O-V V-OH H-bonding acac Si-OH Catalytic Activation Spectroscopic Characterization FTIR Spectroscopy VOx/MCM VO(acac)2 + MCM Blank MCM

16. O V O O O S S S Catalytic Activation Spectroscopic Characterization FT-Raman v2o5 1042 cm-1 997 cm-1 Raman frequency ~ V-O bond length ~ VOx coordination 1.3 mmol/g  1042 cm-1 : (V=O) tetrahedral 997 cm-1 : (V=O) octahedral 0.7 mmol/g 0.4 mmol/g • VOx/MCM catalysts < 1 mmol/g V : • tetrahedrally coordinated VOx • Raman spectroscopy is very sensitive towards micro-crystalline V2O5 0.2 mmol/g

17. VOx coordination Band position (nm) tetrahedral isolated 250, 300 tetrahedral 1D chains 350 square pyramidal 410 octahedral 470 Catalytic Activation Spectroscopic Characterization UV-VIS-DRS OV charge transfer bands ~ VOx coordination 18 16 Progression of polymerisation as a function of the surface loading : 14 (c) 1.3 mmol/g V 12 (b) 0.7 mmol/g V 10 (a) 0.4 mmol/g V Kubelka Munk Units 8 (a)Isolated tetrahedral (b) isolated + 1D chains (c) isolated + chains + V2O5 crystals 6 4 2 0 200 300 400 500 Wavelength (nm)

18. Catalytic Activation Catalytic Performance Oxidation of methanol (at T = 400°C) Tetrahedral VOx :  activity increases with V loading  high formaldehyde yield Formation of V2O5 clusters :  activity decreases  selectivity decreases drastically  Conversion  COx  Formaldehyde+ dimethylether

19. Catalytic Activation Catalytic Performance Oxidation of methanol (at T = 400°C) On pure, grafted and incorporated VOx-MCM materials for different vanadium loadings Acidic sites Dimethylether (DME) Basic sites Carbonoxides (CO) Redox sites Formaldehyde (FA)

20. Catalytic Activation Supported Mixed Oxide Catalysts Combining different oxide phases  Synergy or complementary properties  Improved catalytic performance Synthesis of a new mixed oxide phase using the Molecular Designed Dispersion method : Vanadium oxide + Tantalum oxide Structural characterization FTIR, FT-Raman, UV-VIS-DRS Surface properties Adsorption of pyridine Catalytic performance

21. O O O V V V O O O O O O O O O S S S S S S S S S S S O O Ta Ta O O O O O O S S S S Catalytic Activation Supported Mixed Oxide Catalysts FTIR FT-Raman Ta=O V=O Si-O-Ta Si-O-V Ta=O VOx-TaOx TaOx VOx Blank Well-mixed and well-dispersed VOx-TaOx catalysts

22. 100 90 80 70 60 Selectivity (%) 50 40 30 20 Dimethylether 10 Methylformate 0 Formaldehyde VOx TaOx (0.4 mmol/g) VOx-TaOx (0.2 mmol/g) (0.4 mmol/g V + 0.2 mmol/g Ta) Catalytic Activation Supported Mixed Oxide Catalysts Oxidation of methanol (at T = 250°C) Redox site : formaldehyde, methylformate Acid site : dimethylether Redox site VOx Acid site TaOx + VOx-TaOx Catalyst with active redox and active acid sites

23.       Relatively large mesopores Large amount of micropores Thick pore walls Incorporation of hetero-elements in thicker walls Higher hydrothermal and mechanical stability Use of non-toxic, biodegradable, non-ionic triblock copolymers as template SBA-15 and SBA-16 Promising Materials Qualities of SBA materials

24. SBET (m³/g) Vp (ml/g) rp (nm) SBA-15 SBA-16 MCM-48 900 800 1200 1.3 0.6 1.0 5.0 3.0 1.4 SBA-15 and SBA-16 A comparison with MCM-48

25. Tuning pore size distribution Changing synthesis conditions Pore size engineering • size of surfactant • use of swellers • Synthesis temperature

26. EO 4 units 17 - 37 units 132 units lamellar hexagonal cubic PO 30 units 70 units 3 nm ø 8 nm ø Pore size engineering Size of surfactant Triblock copolymers (pluronics) (EO)x(PO)y(EO)x Length of EO blocks (ethyleneoxide) Characteristic for mesophase (structure) Wall thickness Length of PO blocks (propyleneoxide) influences porediameter

27. Pore size engineering Addition of swellers (TMB, 1,3,5- trimethylbenzene) Pore enlargement mesocellular foam MCF

28. Pore size engineering In situ control of mesopore radius by changing the synthesis conditions using the same surfactant (EO70PO20EO70) The SBA-15 materials were aged for 16 h at different temperatures: B D A Sample A = 75°C Sample B = 90°C Sample C = 105°C C A part of non calcined sample A had a hydrothermal treatment for 3 days at 100°C (Sample D)

29. Pore size engineering Variable micro/mesopore volume In situ control of micro/mesopore volume ratio by changing the synthesis conditions using the same surfactant (EO70PO20EO70) Sample A: aged for 16h at 75°C Sample D: part of non calcined sample A after a hydrothermal treatment at 100°C for 3 days

30. Morphologies of SBA Fibers of SBA

31. Morphologies of SBA cm range high µm range low µm range Spherical SBA

32. Morphologies of SBA Growth mechanism of spherical SBA

33. TiOx / SBA-15 VOx / SBA-15 100 100 80 80 / Selectivity (%) Selectivity (%) 60 60 / Conversion 40 40 Conversion 20 20 0 0 100 200 300 400 500 100 200 300 400 500 Temperature (°C) Temperature (°C) Post-synthesis modification Activation of SBA materials by MDD and Catalytic performance Catalytic activity of VOx and TiOx / SBA-15 in SCR of NO with ammonia. DeNOx: 4 NO + 4 NH3 + O2 4 N2 + 6 H2O Not active below 350°C Not higher than 55% of conversion

34. SBA Catalytic performance Mixed oxide TiOx - VOx / SBA-15 catalyst VOx - TiOx / SBA-15 100 • Very active in a low temperature range • ~100% NO conversion (above 250°C) • ~100% N2 selectivity (all temp. range) (%) 80 Selectivity 60 / 40 Conversion 20 0 100 150 200 250 300 350 400 Temperature (°C)

35. Related SBA materials In situ formation of amorphous siliceous microporous nanoparticles Post-synthesis modifications Simultaneous formation and activation metal oxides nanoparticles zeolite based nanoparticles

36. PHTS SBA-15 and related materials Typical N2 sorption isotherms (77K) for various SBA-15 materials open mesopores ink-bottle mesopores

37. Vmeso open Vnarrowed meso Vmicropores PHTS PHTS (Plugged Hexagonal Templated Silica)

38. Related SBA materials In situ formation of amorphous siliceous microporous nanoparticles Post-synthesis modifications Simultaneous formation and activation metal oxides nanoparticles zeolite based nanoparticles

39. Related SBA materials metal oxides nanoparticles (TiO2) tuneable size tuneable crystal phase (rutile, anatase) tuneable number of active sites tuneable porous characteristics (size, number)

40. Related SBA materials In situ formation of amorphous siliceous microporous nanoparticles Post-synthesis modifications Simultaneous formation and activation metal oxides nanoparticles zeolite based nanoparticles

41. SBA and related materials Silicalite-1 nanoparticle deposition TPAOH 20% TEOS VOSO4 ageing 2 days nanoparticles zeolites (vanadiumsilicalite) calcined SBA-15 Dry impregnation acidification (HCl) SBA-15 with zeolitic plugs inside the mesopores

42. SBA and related materials Silicalite-1 nanoparticle deposition Crystalline vanadiumsilicalite-1 nanoparticle Open mesopore narrowed mesopore • nanoparticles can be: • zeolitenanoparticles, metaloxides • microporous, non-porous

43. In situ synthesis strategies Mesoporous materials with zeolite-like walls classic (vanadium) silicalite-1 synthesis mixture: TPAOH, H2O and TEOS, (VOSO4) clear solution containing nanoparticles hydrothermal treatment acidification: pH<1 silicalite-1-like nanoparticles with modified surfactant (vanadium) silicalite-1 zeolite hydrothermal treatment NO TEMPLATE mesoporous surfactant and refluxing long range ordered mesoporous materials with ink-bottle pores short range ordered mesoporous material with tuneable porosity and hydrophobicity Mesoporous materials with silicalite-1-like walls

44. In situ synthesis strategies Mesoporous materials with zeolite-like walls classic (vanadium) silicalite-1 synthesis mixture: TPAOH, H2O and TEOS, (VOSO4) clear solution containing nanoparticles hydrothermal treatment acidification: pH<1 silicalite-1-like nanoparticles with modified surfactant (vanadium) silicalite-1 zeolite hydrothermal treatment NO TEMPLATE mesoporous surfactant and refluxing long range ordered mesoporous materials with ink-bottle pores short range ordered mesoporous material with tuneable porosity and hydrophobicity Mesoporous materials with silicalite-1-like walls

45. In situ synthesis strategies Mesoporous materials with zeolite-like walls classic (vanadium) silicalite-1 synthesis mixture: TPAOH, H2O and TEOS, (VOSO4) clear solution containing nanoparticles hydrothermal treatment acidification: pH<1 silicalite-1-like nanoparticles with modified surfactant (vanadium) silicalite-1 zeolite hydrothermal treatment NO TEMPLATE mesoporous surfactant and refluxing long range ordered mesoporous materials with ink-bottle pores short range ordered mesoporous material with tuneable porosity and hydrophobicity Mesoporous materials with silicalite-1-like walls

46. CH2 CH3 In situ synthesis strategies Mesoporous materials with zeolite-like walls Consequences of acidifying the solution of vanadiumsilicalite-1 nanoparticle EPR and Raman show the loss of a ligand from the silicalite-1 template (TPAOH) EPR HYSCORE spectra of SBA-VS with acidified vanadium silicalite-1 nanoparticles 14N interaction of 14N with V EPR HYSCORE spectra of full-grown vanadium silicalite-1 a) tripropylamine, b) TPAOH 20% solution, c) the full-grown VS-1 zeolite before calcination, d) SBA-VS-15 with acidified nanoparticles before calcinations

47. + In situ synthesis strategies Mesoporous materials with zeolite-like walls Consequences of acidifying the solution of vanadiumsilicalite-1 nanoparticle No mesotemplate HCl HT loss of n-propyl ligand stops the zeolite growth

48. In situ synthesis strategies Mesoporous materials with zeolite-like walls Consequences of acidifying the solution of vanadiumsilicalite-1 nanoparticle hydrothermal treatment NO TEMPLATE Temp tuneable porosity Time tuneable porosity hydrophobicity low pH growth of mesopores by edge-sharing (resembles sol-gel mechanism)

49. Conclusions “Abracadabra” is a well-known incantation in the magic world, although the synthesis of tuned porous materials may still seem an art to many, it nonetheless can be understood to a certain level, appreciated and successfully performed. Making a white powder is by no means the end of the road in preparing porous materials; it is equally important to be able to characterize or to indentify, to engineer the porosity and to activate these materials that have been prepared for a desired application in sorption, catalysis and membranes.

50. Acknowledgements * INSIDE PORES NoE * University of Antwerpen: Prof. P. Cool Vera Meynen Wesley Stevens Liu Shiquan * I.A. Cuza University, Iasi, Romania: A. Busuioc A. Hanu