Mesoporous Materials Amorphous, disordered - silica xerogels Ordered, amorphous walls Pore diameter, d [nm] d>50 2H!TcnIkiťial íl flat** beads) Denuding Pillared tivcnrf wüds{*s : íin-VS, LDI[i j_ Zeolites and n-liirrd -rar-n ali +- (1.5 5 10 3D LUO .1 MCM-43 (2.3 V 0.25}— (3^y 0.1S)_ «Wiax'HHW) SBA-15 ij:;^"-W^'^ ^n>::-.-. ■ zeolite V (0.74/ * 0,1) silica gel (5/2.5} (40 / 20) 3 10 Pore diameter / n/n 30 2 Mesostructure Assembly H í Pr&-formed LC Mesophase Inorganic Precursor -M—X Surfactant {Template) LC Replication Cooperative Sol-Gel + Se II-Assembly Hydro lysí t/ Condensation Me&ostructured Hybrid Network Connection M(OR)r -........>-3Kl Template Elimination I ■■■■■■■- <•■■■......: = -■ Jt^.-. Nano building Block tNBB) Trapping into Template ■■■-.- ■■ Mesaporous Oxide Me »structured Assemblies of MBB Mesoporous Materials MMS mesoporous molecular sieves MCM-n Mobil Composition of Matter M41S Discovered 1992 A - lamellar MCM-50 B - hexagonal MCM-41 C - cubic MCM-48 Inverse hexagonal X-ray Diffraction Pattern MCM-41 (Hexagonal) inn lau Winn a,a aoo im aiG 14JQ y i 11D %x\ sin i—r B Do^wa A4hetfl 10 Possible StTBCtUiVS MCM-48 (Cubic) HI JW n i Ml uj:i m astí rn «1 m nj ŕ JV- «0 tu 4E 1T* £2 irj .«vp' \ JJ1 1U ,^_ i i i r r i i r i 2 4 a 0 1 Deans* 2-HWta MCM-50 (Stablllzod Lamellar) ige:- m rtW 1 1 10D Bij raa 1 ijuca 1', 1 1 '■■ ill i i —1----------1-------- "T------=1 D í 1Í> IB ZO 29 30 Degree» 2-Utflto Silica Shoots 5 Supramolecular templating Surfactants - amphiphilic molecules, polar (head group)and nonpolar (chain, tail) part lyophilic, lyophobic Ionic surfactants, cationic, anionic, zwitterionic Nonionic amines, polyethyleneoxides A - normal surfactant molecule B - gemini C - swallow tail ABC 6 n a Surfactants Hydrolrope (flexible Surfactant) Bolaform surfac-t&n-t l Diblock copolymer surfactant Classical surfactant (r*gitl Surfactant Gemini surfactant {dimwit) Polymeric surfactant 7 Surfactants Anionic • sulfates: • sulfonates: • phosphates: • carboxylates: Cationic • alkylammonium salts: • dialkylammonium salts Noionic • primary amines: • polyethyleneoxides: CnH2n+1OS03 W C„H2n+iS03H C„H2n+1OP03H2 CnH2n+1COOH CnH2n+1(CH3)3NX X = OH, CI, Br, HS04 (C16H33)2(CH3)2N+Br CnH2n+1NH2 HO(CH2CH20)nH 8 Supramolecular templatíng Phase diagram of C16TMABr . . , , i.. i i.i CMC = critical micelle cone. 0 10 20 30 40 50 60 70 80 90 100 koncentrace (hm.%) Micelles - Supramolecular Templates F^rJK S|]llCfÍCAl . jwiwsfjA as >i ■a 'v. ■ &Í& I™0 Micellar shapes A -spherical, B - rod-like, C - lamellar Micelles in media A - normal, in polar solvent, H20 B - inverse, in nonpolar solvent, organics Micellar shapes Micellar structures A ) sphere, B ) cylinder, C ) planar bilayer, D ) reverse micelles, E ) bicontinuous phase, F ) liposomes). Critical packing parameter - CPP CPP = VH/a0lc VH volume of the hydrophobic part, a0 surface area of the hydrophilic part, lc critical chain length: lc < 1.5 + 1.265 n [Á] n number of carbon atoms. lc depends on the chain shape. Head group area a volume V alkyl chain 13 CPP Surfactant < 0.33 linear chain, large head 0.33 - 0.5 linear chain, small head 0.5 -1.0 two chains, large head micelle shape spherical cylindrical bilayers Surfactant Molecules Conical {icecream cone, A) Inverse conical {champagne cork, B) 15 Surfactant Molecules -14 nm 5-10 nm micelle 4-5 nm [ inverse cubic phase (ů) -7 nm ■ ■Mldl.ir inverse hexagonal pháte high low walŕr íonlent 16 A. Lx= micellar solution; Nc = nematic phase; Hj = normal hexagonal phase (MCM-41; SBA-15); Vj = normal bicontinuous cubic phase (MCM-48); La = lamellar phase (MCM-50) path A, the micellar solution route path B, the lamellar phase route path C, the nematic phase route 17 Mechanism of the mesoporous material formation (hexagonal, MCM-41) LCT Liquid Crystal Templating mesostructured material ___ micellar rod surfactant micelle ________ta- M ■wfk 4$ny °% V' V ■* ů--^;^-o r Áffo/ t j^OaJfi^^pr^ lyfl^H^y 1 ľ ůoaa* %W inorganic presursor "H-Lu^^HL* ' J^^t""'1 '■' mesoporous material surfactant removal 18 General Liquid Crystal Templating (LCT) Mechanism VŽaÚK. \ suTracLml 4uŕx* ictorganic molecular spůde-s 4-a) ■j) ans 19 SLC Silicatropic Liquid Crystals precursor solutions ctfw ***** o tf * a * o i v • / • V micelles and isolated cationic inorganic silicate anions surfactant molecules (for example, D4R oligomers) phase ^^g^äl^transforrnation' íameítar SLC hexagonal SLC recursor Solutions ^ =CTA+ 0=Br (S Ion Exchange © Assembly of theSlllcatroplc Liquid Crystal Me&opha&e Phase Transitions 21 Lamellar to Hexagonal Transformation oil »Ante Cun^totim T BDCM4lntfi Silicate Rod Assembly +r w 23 • Electrostatic interactions a) si Ie# b) SI+ c) SXI+ ie£- rx9^ I = silicate S = trimethylammonium I = Fe2+,Fe3+,Co2+,Ni2+, Mg2+, Mn2+, Pb2+, Al S = sulfonane I = silicate - polyelectrolyte positive charge X = C1 S = trimethylammonium d) S"M+r iW I = aluminate M = Na S = phophate • Hydrogen Bond a) S°I° oTo b) Nur 0 0 I- -N- • Covalent Bond a) S-I I----S I = silicate S = ammine I = silicate N = polyethylenoxide I = niobáte, tantalate S = ammine 25 26 T 7-tnh Chürflt; 4* ľ ■■■ ■■■■ 1 _■ ■_ Ld SťRiLlhf ť Imrfiŕ h SiliťA Uiaauli-ĽH = ■ô S 1^^^"^^^^- !7 . 1 . _L , 1 . 1 1 ■' 1 ■ * 2 4 pH 10 ---------■-----------■—w-12 x™+ rsí*-<&w, p"<2, a-o «^ pH >9 Strong eiKirxHUiJť inieinaciLoji Wť4ik byilnigni- bondHg InlĽniLľliun MCM-41 -.•'"5«í**^ixr" 100 A Prepared with Mešity lene Addition 28 TEM micrograph of hexagonal molecular sieve 29 TEM image of the Pd-grafted mesoporous silicate material Silicate Layer Puckering WMMV 31 Charge Density Matching osu* : =£> 32 Folding Sheets kane mite silicate-organic mesoporous complex material 33 XRD of hexagonal MCM-41 (1QO) 70QC eoooH 50ÜO *r 4i>oo 3 300 2 000 100O- i 300 250 ? 200 (200) iiii i i i ■ ■ i|ii^i|-iii| i f i ■ | iii i | ' ' ■ ' b ' ' * ' t Z 3 4 5 Ů r S 9 10 2 a (dŕgr&K)_________________ (.£00) i i ■ I t M i 111" ' I n " I ' " ' n ' ■ P j I ' I ■ I I I I ■ j ■ ■ I I j ■ ■ ■ ■ j I I ■ ■ n ■ I I j ■ ■ ■ ■ I I ■ ■ ■ J' ■ ' ■ ľ ■ ' ■ i ! 345 C 7 8 9 10 2 0 (degrees) 34 XRD of lamellar MCM-50 Z50Ü £000 A e isq -H2Os -C02) -NO, Mesoporous Platinum Metal H2[PtCl6] or (NH4)2[PtCl6] C16(EO)8 Assembly of liquid crystalline phase Reductants: Fe, Zn, Hg, NH2NH2 Washed with acetone, water, HCl SEM (upper) and TEM (lower) images of mesoporous Pt metal show particles 90-500 nm in diameter and a pore diameter of 30 A and a pore wall thickness of 30 A. 41 Surface Silanols in MCM-41 Pores m r\ < << I ď" —Ki JK7 z^zz^y 42 ' ^Fe. Cl Cl M mbn Vi* HO—Bi -M HO OH