Metal oxide nanoparticles: Synthesis and Reactivity

Transcription

1 UMR - CNRS 7574 Laboratoire Chimie de la Matière Condensée de Paris, Site Collège de France Groupe Nanomatériaux Inorganiques Metal oxide nanoparticles: Synthesis and Reactivity Corinne Chanéac Environmental Nanotechnologies, 7-8 July 2011, Aix en Provence, France

2 About the Research into Safety of Manufactured Nanomaterials Stage 1: List of Endpoints Nanomaterial Information/Identification Physical-Chemical Properties and Material Characterization Environmental Fate Environmental Toxicology Mammalian Toxicology Material Safety

3 About the Research into Safety of Manufactured Nanomaterials List of Manufactured Nanomaterials (14) Fullerenes (C60) Single-walled carbon nanotubes (SWCNTs) Multi-walled carbon nanotubes (MWCNTs) Silver nanoparticles Iron nanoparticles Carbon black Titanium dioxide Aluminium oxide Cerium oxide Zinc oxide Silicon dioxide Polystyrene Dendrimers Nanoclays Soft Chemistry

4 Morphology and Nanoparticles Gœthite Anatase Rutile Formation of natural crystals in geological conditions

5 Aqeous Sol-Gel Process for nanoparticle synthesis [Ti(H 2 ) 6 ] 3+ H M M H hydrolysis Strong acidity :Catalysis of oxolation [Ti(H) 4 (H 2 ) 2 ] 0 H 2 M H M H 2 Rutile Condensation : olation Weak acidity: olation then oxolation Bottom-up Approach Anatase

6 Morphology and Nanoparticles Gœthite Anatase 800 nm 20 nm Durupthy,.; Bill, J.; Aldinger, F. Cryst. Growth Des. 2007, 7, 2696 Rutile w 56 nm Chem. Comm., 5, 2004, pp nm JACS, 2007,129 (18),5904

7 Morphologie et Nanoparticules Gœthite Anatase 800 nm 20 nm Durupthy,.; Bill, J.; Aldinger, F. Cryst. Growth Des. 2007, 7, 2696 How control the nanocrystal growth? Rutile w 56 nm Chem. Comm., 5, 2004, pp nm JACS, 2007,129 (18),5904

8 Surface energy : origin Surf / T 0,6 0,4 Change in chemical and physical properties 0,2 Solid formation nm D 5 DG formation = ndg Bulk + DG surface Variation of surface energy with the particle size (Sodium Chloride): >0 Side Total Surface aera Surface Energy (cm) (cm 2 ) (J/g) 0,1 28 5, , , (1mm) 2, , (1nm) 2, Calculation for a cube of Sodium Chloride Surface Sci. 60, 445, 1976 Huge surface energy for nano-solids - Thermodynamically unstable system

9 Surface energy : origin Unstability of nanometric colloidal dispersion: DG = ndg Bulk + DG surface E surface : stability Sintering, swald ripening Spontaneous evolution of nanoparticles to minimise the surface contribution Surface : motive power of growth How determine the surface energy?

10 Surface energy : origin DG = ndg Bulk + DG surface g = (dg/ da) n i, T, P g : surface energy energy requiered to create an unit of aera Bond strength g = ½ N b e r a Number of broken bonds per atom Surface atomic density Rough estimation of surface energy: - surface relaxation - surface restructuring with formation of new chemical bond - same value of e for all the atoms - no entropic consideration/ pressure or volume Surface Sci. 60, 445, 1976

11 rigine de l énergie de surface g = ½ N b e r a FCC Structure Coordination number of 12 Lattice parameter a N b = 4 N b = 5 N b = 3 g {100} = ½ 2/a 2.4.e = 4 e/a 2 g {110} = 5e/ 2 a 2 = 3,52 e/a 2 g {111} = 2 3e/a 2 = 3,46 e/a 2 Surface energy depends of the index of facets : low index facets = low surface energy

12 Relation between surface energy and crystal shape Shape of nanoparticle : total surface energy reaches minimum Wulff construction Equilibrium crystal Bi doped with Cu Morphologies for a 2D crystal for 10 and 11 faces

13 Surface energy at the atomic scale Brønsted basic site Site m 3 H + M H d d-1 M M M M M 5 nm Site m 2 H + M H d-1 M H M H d-2 M T. Hiemstra et al., J. Colloid Interface Sci. 184, 680 (1996) Model of multisite complexation, MUSIC 2 K protonation = f (structure, hydratation) M n (nv-2) + H + solv M n H (nv-1) K n,1 M n H (nv-1) + H + solv M n H 2 nv K n,2 -Ln K n,x = - A(SS j -2+m) A = 19,8 H m 1 p+m = 2 H m 2 p+m = 1 ou 2 H m 3 p+m = 1 S S j = S i S Me + p S H + m(1- S H ) S H = 0,8

14 Surface energy at the atomic scale Charge de surface (C.m 2 ) Model of multisite complexation, MUSIC 2 Example : face 111 h of magnetite, 2 sites m 2 and m 3 3,3 10,86 ph Fe 2 -H 2 +0,8 Fe 2-H -0,4 Fe 3 -H +0,6 Fe , h 100 Somme pondérée PZC ph Good valuation of surface charge and of point of zero charge

15 Surface energy at the atomic scale Brønsted basic site Site m 3 H + M H d d-1 M M M M M 5 nm Site m 2 H + M H d-1 M H M H d-2 M T. Hiemstra et al., J. Colloid Interface Sci. 184, 680 (1996) DG surface >0 ga D g = g - g 0 = RT F Gibbs s Law : Dg = -S k i dm i I I + s 2 - s max ) ln( 1 - s ) s max Surface charge density J.P. Jolivet et al., J. Mater. Chem., 2004, 14, 3281

16 Surface Energy Effect Metastable bject DG = ndg Bulk + DG surface > 0 Two ways ga (g,surface energy) (A, surface area) Decrease of g Decrease of A : swald ripening Gibbs Law : Dg = -S k i dm i D g = g - g 0 = RT F I I + s 2 - s max ) ln( 1 - s ) s max Density of Surface charge Previously described For H>PCN g decreases when the charge density, s, increases J.P. Jolivet et al., J. Mater. Chem., 2004, 14, 3281

17 Surface Energy Effect Surface charge density Log [Fe x (H) y ] ,0 1,1 1,2 Size, Shape = f(surface energy) 1,4 solubility -10 3,4 2,2 1,3-12 PZC ph As s = f(ph) Site 1 s s 1 + pk1 PZC (point of zero charge) The surface energy is lesser far from the PZC s 2 + pk2 s 1 - s ph s Site 2

18 Isotropic Nanoparticles Size = f(surface Energy) Precipitation of FeCl 2 / FeCl 3 : Fe 3 4 magnetite IRM, Hyperthermia Precipitation of TiCl 4 : Ti 2 anatase Photocatalysis, Photovoltaic ph Pottier A. (1999), Thèse UPMC, Paris 6 D (nm) D (nm) week week Surface charge (C/m 2 )c Surface charge (C/m 2 ) ph Charged surface = stopped growth ph J. of Colloid Interface Sci., 1998, 205, 205 & J. Mater. Chem., 2003, 13, 877

19 Isotropic Nanoparticles Size = f(surface Energy) Precipitation of FeCl 2 / FeCl 3 : Fe 3 4 magnetite IRM, Hyperthermia ph 10 9 nm 50 nm ph After 3 weeks aging at ph 13.5 at 25 C Stability of nanoparticle = f(solution acidity), reversible phenomena

20 Anisotropic Nanoparticles Precipitation of Al(N 3 ) 3 : g-al(h) boehmite 0,9 (001) (100) 0,8 g (J/m 2 ) hkl 0,7 (100) Wulff construction : Equilibrium crystal = faces of lesser energy 0,6 (001) Morphology = f(surface Energy of each face) 0,5 0, ph Handbook of Porous Materials, Ed. F. Schüth, Wiley-VCH, 2002, p & J. Mater. Chem., 2004, 14, 1-9

21 Anisotropic Nanoparticles Precipitation of Al(N 3 ) 3 : g-al(h) boehmite ph = 4.5 0,9 0,8 g (J/m 2 ) hkl L= 4,5 nm e = 3.7 nm (001) 5 nm small aggregated pseudo-isotropic particle 100 nm ph = 6.5 0,7 (100) L= 8 ± 1 nm e = 3.7 nm (100) 0,6 (001) (001) pseudo-hexagonal platelets 50 nm 0,5 ph = 11.5 L= 13 ± 4 nm e = 4.9 nm 50 nm 104 réf 0, ph diamond shape platelets Handbook of Porous Materials, Ed. F. Schüth, Wiley-VCH, 2002, p & J. Mater. Chem., 2004, 14, 1-9

22 Anisotropic Nanoparticles IEP Zeta potential (mv) Precipitation of Al(N 3 ) 3 : g-al(h) boehmite C B A 50 nm 50 nm 50 nm 10,5 10 9,5 9,5 C 10,2 (001) (100) A B C 9 8,9 (100) 10 8,5 8 7,5 A B (001) (001) ph Electric Properties = f(morphology)

23 Anisotropic Nanoparticles Boehmite Gama Alumina : topotactic transformation b (110) al calcination (001) b b (100) b 450 C (110) al (111) al (100) al Boehmite Alumine g 50 nm C 20 nm Morphology is kept after the heat treatment Euzen, P., et al., Handbook of Porous Solids, Wiley-VCH Verlag GmbH, 2002, Vol. 3,

24 Surface complexation Complexing molecules and growth of cristallites Precipitation of Al(N 3 ) 3 with polyols: g-al(h) boehmite [polyol]=0.007m Polyols Dicarboxylates C2 H H C2 - H - C3 H H H C3 C4 H H - - H H C4 - - C5 H H H H H H H C6 H H H H H H Hydroxycarboxylates

25 Surface complexation by polyols Precipitation of Al(N 3 ) 3 with polyols: g-al(h) boehmite ph = 11.5 [Al]=0.07M 50 nm 104 réf [polyol]=0.007m H H éthylène glycol 50 nm 6.0 nm dulcitol H H H H H H C2 C3 50 nm glycérol H 12.6 nm H H 3.6 nm 6.0 nm 50 nm C6 C5 C4 50 nm 6.5 nm 12.0 nm erythritol H H H H arabinitol H H 50 nm 4.2 nm 6.6 nm 5.2 nm H 10.6 nm The size of nanoparticles decreases with the length of polyols H H

26 Surface complexation by polyols Surface spécifique (m²/g) Precipitation of Al(N 3 ) 3 with polyols: g-al(h) boehmite [polyol] 10 % mol threo erythro xylitol ribitol dulcitol average standard synthesis threo Xylitol : 290 m 2 /g 250 erythro Stereochemistry effect Nombre de fonction H Ribitol : 180 m 2 /g Chiche D. (2007), Thesis UPMC- IFP, Paris 6 Heterogenous Catalysts, Elsevier, 2006, 393

27 Surface complexation by polyols S Precipitation of Al(N 3 ) 3 with polyols: g-al(h) boehmite Stabilisation énergétique des faces 50 nm ethylene glycol R = L/e threo erythro moyenne synthèse standard C2 6.0 nm 12.6 nm (%) nm 50 C3 glycerol 6.5 nm 12.0 nm Nombre de fonction H C4 50 nm erythritol 5.2 nm 10.6 nm 2 Aspect ratio evolution : Preferential adsorption upon lateral surfaces 50 nm 4.2 nm nm Specific adsorption of Polyols on face: Selectivity of adsorbed species C5 arabinitol Phys. Chem. Chem. Phys., 2009, 11,

28 Surface complexation by polyols E ads (0K) = -87 kj.mol -1 «Nest» effect DFT calculations Preferential adsorption upon lateral surfaces : concavitie and stabilisation E ads (0K) = -118 kj.mol -1 Phys. Chem. Chem. Phys., 2009, 11,

29 Surface complexation by hydroxy carboxylate S 101 (%) poly(hydroxy)carboxylates 0.007M 65 2,2 50 nm - succinate R = l/e malate 1,6 50 nm 50 Selective adsorption on face standardsuccinate malate Carboxylate tartrate H Hydroxy carboxylate chemisorption Geffroy 1999, Haines 1974, Martell tartrate H H 1,1-50 nm X Al - Al X - Al - - Al Size variation is not homothetic : Strong decrease of anisotropy Acidity of H groups is strengthened by the complexation

30 Surface complexation by hydroxy carboxylate ~ 2,7 Å ~ 2,9 Å - - ~ 2,8 à 5,3 Å μ 1 -H / μ 1 -H μ 2 -H / μ 2 -H μ 1 -H / μ 2 -H D(-) (Å) 2,7-4,0-4,7-6,3 2,5-4,7-5,5-6,3 2,5-2,8-3,8-4,9-5,3-5,7 Lower reactivity of face due to m 2 -H sites. Increase of face stabilization with the distance between CH groups: more available adsorption sites.

31 Surface complexation and shape of anatase nanoparticles Anatase nanoparticles obtained without complexant In presence of glutamic acid nly 101 faces 20 nm In presence of oleic acid Durupthy,.; Bill, J.; Aldinger, F. Cryst. Growth Des. 2007, 7, 2696 Ethylenediamine (100) faces (100) and (001) faces 30 nm Matijevic, J. Colloid Interface Sci. 103 (1985) Sugimoto, T.; Zhou, X. P.; Muramatsu, A. Journal of Colloid and Interface Science 2003, 259, 53

32 What are the relevant parameters to control the growth of nanoparticles? Log [Fe x (H) y ] Size, Shape = f(solubility) ,0 1,1 1,2 Size, Shape = f(surface energy) 1,4 solubility ,4 2,2 1,3 PZC ph

33 Titanium oxide Nanoparticles 3 polymorphs Pigment : paints, papers, plastics, cosmetic and pharmacy Photocatalysis, photovoltaic Anatase (I4 1 /amd) DH f ( kj.mol -1 ) r (g/cm -3 ) Brookite (Pcab) Rutile ,84 4,17 4,26 (P4 2 /mnm) Mine Falls Park, Nashua, NH Mina Maria,Caneca, Sonora, Mexico Stony Point, Alexander County, NC Cristalline structure depends on synthesis conditions

34 Titanium oxide Nanoparticles lation Alcalinisation 2 ph 6 [Ti(H) 4 (H 2 ) 2 ] 0 Ti 2 xolation Thermolysis in acidic medium Ti(H) 2 (H 2 ) C Ti(H) 2 X 2 (H 2 ) 2 0 Ti(H) 4 (H 2 ) 2 0 Ti 2 anatase brookite Thermolysis with chlorides rutile

35 Titanium oxide Nanoparticles Thermolysis of TiCl 4 : Ti 2 rutile Weak nucleation : slow precipitation High solubility : favour the growth R = 6 R = 10 R = 13,5 R = length wide 1 M 2 M 4M solubility increase [H + ] sol (110) (002) (002) (110)

36 Relative proportion (%) Titanium oxide Nanoparticles Thermolysis of TiCl 4 with chloride : Ti 2 brookite TiCl 4 0,15 M / HCl / 95 C 48 hours Cl/Ti ,6 17,3 24,0 30,6 37,3 44,0 brookite 3M Rutile 48 h 3 nm [HCl] / mol dm <Cl/Ti <35 [Ti(H) 2 Cl 2 (H 2 ) 2 ] A. Pottier, S. Cassaignon, C. Chaneac, F. Vilain, E. Tronc, J.P. Jolivet, J. Mater. Chem., 13, 877 (2003)

37 Titanium oxide Nanoparticles Thermolysis of TiCl 4 with chloride : Ti 2 brookite Structure control by a complexing agent A. Pottier et al. J. Chem. Mater. 2001, 11, 1116

38 Titanium oxide Nanoparticles Hydrolysis of Ti(III) 0, ,5 Ti(H 2 ) 3+ 6 Ti x (H) a (H 2 ) z+ b Ti 3+ Ti 3+ xidation xid. /Précip. Precipitation Precipitation xidation ph rutile brookite rutile anatase S. Cassaignon et al., J. Phys. Chem. Solids (2007), doi: New Morphologies for Ti 2

39 Growth control and Seeding Ti 2 Rutile : TiCl 4 3 M / HN 3 15M / 120 C 24 hours Q. Huang, L. Gao, Chem. Letters, 2003, 32,7 9 Seed 12 Mesoparticles R = L/l 50 nm 50 nm seed-mediated growth process + Growth solution : C(Ti 4+ )=0,3M Dessombz A.,Thesis UPMC-rsay,Paris nm L = 160 ± 40 nm D = 15 ± 5 nm q Volume fraction : f = 13,3% JACS, 2007,129 (18),5904

40 Properties of long nanorods Nematic Proportion Isotropic Biphasic Collaboration : Patrick Davidson, LPS rsay, Pierre Panine, ESRF Grenoble 100 µm f = 8,2% nematic droplets Nematic phase First order transition f = 10,6% 0.2 S=0,75 ± 0,05 d ~ 50 nm Volume Fraction (%) Dessombz A.,Thesis UPMC-rsay, Paris 11 JACS, 2007,129 (18),5904

41 Properties of long nanorods Intensité (ua.) Degradation Photocatalysis study 1 cm Methylene blue degradation (10-5 M) UV lamp 365 nm, 1h Methylene blue Dessombz A.,Thesis UPMC-rsay,Paris 11 Film oriented ( ) Film in rotation agitation 0.2 Polarizer // Film oriented (//) 0.05 Rotated Film riented Film (nm) riented aggregation: Increase of the photocatalytic activity JACS, 2007,129 (18),5904 Collaboration : Patrick Davidson, LPS rsay, Pierre Panine, ESRF Grenoble

42 Properties of long nanorods Anisotropy of electric properties; Photoactivation of current

43 Conclusion Aqueous chemistry of metal cations: environmentally friendly, Low cost Versatile way to tune oxide nanoparticles Size, shape and crystalline structure Identification of relevant synthesis parameters to tune size and shape: ph and acidity, used of polyfunctionnal complexant : Polyols, Polycarboxylates Surface energy and solubility of nanoparticles are the driving force of their evolution

44 Acknowledgements Sophie Cassaignon, MdC livier Durupthy, MdC David Portehault, CR Jean-Pierre Jolivet, Prof. Elisabeth Tronc, CR Tamar Saison, Hanno Kamp, David Chiche, Nicolas Chemin, Arnaud Dessombz, (PhD) Agnès Pottier, Cédric Froidefond, Micaëla Nazaraly Yuheng Wang, Anne Carton, Roberta Brayner, Pierre Gibot (Post Doc), Christelle Roy (Master) Microscopy staff Gervaise Mosser, Patrick Le Griel (LCMC) Patricia Beaunier (UPMC) Dominique Jalabert, Fabienne Warmont (Univ. rléans) Funding IFP French institute of petrol, Lyon Rhodia, Aubervilliers Draka Comtech, Marcoussis Saint Gobain Research, Aubervilliers Lhoist, Belgium

45 University Pierre et Marie Curie, Paris, France Jean-Yves Bottero, Mark Wiesner Mélanie Auffan, Jérôme Rose CEREGE Thank you for your attention