Metal nanoparticles and nanomaterials: Radiolytic synthesis and applications

Transcription

1 Metal nanoparticles and nanomaterials: Radiolytic synthesis and applications Hynd Remita Laboratoire de Chimie Physique, CNRS-UMR 8000 Université Paris-Sud, Orsay

2 Radiolytic synthesis of metal clusters g, e - H 2 O e s-, H 3 O +, H, OH, H 2, H 2 O 2 Selective reducing environment (CH 3 ) 2 CH OH + H (CH 3 ) 2 C OH + H 2 (CH 3 ) 2 CH OH + OH (CH 3 ) 2 C OH + H 2 O Isolated atoms as precursors Homogeneous nucleation J. Belloni, Rad. Res., 150, S9, (1998) J. Belloni et al., New J. Chem., 1239 (1998) J. Belloni, Cat.Today, 113, 141 (2007)

3 Reduction and nucleation processes studied by pulse radiolysis pulse e - aq + Ag + Ag 0 k = 4.8 x dm 3 mol -1 s -1 Ag 0 + Ag + Ag 2 + k = 8.5 x 10 9 dm 3 mol -1 s -1 Ag Ag + Ag 3 2+ k = 2 x 10 9 dm 3 mol -1 s -1 Ag Ag 3 2+ Ag Ag + Cinétique de nucléation de clusters d argent Fast Kinetics Center Elyse E. Janata et al., J. Phys. Chem., 98, 10888, (1994) E. Janata, J. Phys. Chem., 107, 7334, (2003)

4 Metal nanoparticles synthesized by radiolysis Silver nanoparticles stabilized by PVA (polyvinyl alcohol) Gold nanoparticles stabilized by PVA and deposited on mica Radiolysis monodispersed particles size control

5 Stabilization of metal clusters by ligands or polymers Ligands (CO, EDTA, calixarenes ) Polymers (polyacrylate) * Functional group having affinity for metal NPs m+ Ag n STM image of blue silver clusters Ag 7 3+ or Ag 8 4+ (stable in air) Ag NP stabilized by calix[8]arene - steric effect M. Mostafavi et al., Rad. Phys. Chem., 41, 453, (1993) I. Lampre et al. to be submitted.

6 Percentage of particles Percentage of particles Percentage of particles Dose rate effect on size distribution of silver clusters 70 electron beam Gy s C 6+ ion beam 200 Gy s g rays 1.75 Gy s Diameter (nm) (Aqueous solution : M AgClO 4, 0.1 M PVA, 0.2 M 2-propanol) H. Remita et al., Radiat. Phys. Chem, 72, 575 (2005)

7 Dose rate effect on cluster size distribution The final size depends on the dose rate At higher dose rate smaller particles are obtained

8 Silver particles Nanometric Particles (Conducting Pastes for electronics) nm M. Mostafavi et al., Collaboration with CLAL, since 1989

9 Bimetallic nanoparticles synthesized by radiolysis

10 Dose rate effect on bimetallic cluster structure At low dose rate, the less noble metal is coating the core made of the more noble metal in a core-shell structure At high dose rate, alloyed clusters are obtained J. Belloni, H. Remita in Radiation Chemistry, EDP Sciences, p97-116, 2008.

11 Dose rate effect on bimetallic nanoparticle structure: Au-Ag system ([Au III Low ] = [Ag I dose ] = 5 x 10-4 rate: M, [PVA] 3,8 = 0,1 kgy.h M, l = 0,2-1 cm) High dose rate: 35 kgy.h 1 Au n /Ag n core-shell Ag-Au Alloys J. Phys. Chem.B, 102, 4310 (1998)

12 Bimetallic nanoparticles Synthesis of nanoparticles of controlled stucture and composition M/N bi-layered M-N Alloy Application in catalysis and fuel cells Fuel cells: Methanol oxidation (Pt-Ru, Pt-Au) Ethanol oxidation (Pd-Au) Oxygen reduction (Pt-Co, Au-Fe) H + reduction (Pt, Au-Fe) Catalytic convertors, NO X removing (Pt, Pt-Sn) Selective hydrogenations (Pd, Pd-Au, Pd-Ag) Ksar et al. Chem. Mater., 2009, 21, R. Doherty, J. Catal. 2012, 287, 102.

13 Shape control

14 Gold nanorods Gold nanorods 50 nm Shift of the longitudinal plasmon band towards larger wavelengths with increasing the aspect ratio F. Kim et al., JACS, 2002, 124, C. J. Murphy et al., MRS Bulletin, 2005, 30, 349

15 Au nanorods in PVA matrices Polyvinyl Alcohol PVA(H) + OH PVA + H 2 O PVA(H) + H PVA + H2 2 PVA PVA-PVA (cross linking) Irradiation induces crosslinking of the polymer Formation of a hydrogel Microtomie TEM montrant des NRs bien dispersés dans l hydogel PVA Abidi, W. et al, J. Phys. Chem. C (2010) 114,

16 Formation of Nanofilms X-ray radiation under grazing incidence (ESRF) miror Langmuir cuve Incident X-ray beam X-ray scattering monochromator slits q in < q c 4,5 nm x monolayer of C 21H23-COOH (behenic acid) + Adsorbed Ag + ions nanofilm of Ag Interaction of X-rays with the interface Follow the evolution of the structure at the surface F. Muller et al., Langmuir, 20, 4791, 2004

17 Nanoparticles (ligands, polymers) Micelles Oxides, Carbon, Semiconductors Metal Electrodes J. Belloni, H. Remita in Radiation Chemistry, EDP Sciences, p97-116, Polymeric Membranes Zeolites Carbon Nanotubes Mesophases, Mesoporous Materials

18 Matériaux microporeux et nanoparticules métalliques: Application aux domaines des Capteurs Chimiques a. b. c. De la suspension colloïdale... au film mince Zéolithe en Suspensions colloïdales et films minces Synthèse par voie radiolytique Etudes structurales par diffraction X aux petits angles Spectroscopies résolues en temps (photolyse et radiolyse) Chemistry of Materials (2006), Sensors and Actuators (2007) Superlattices and Microstructures (2008) Research on Chemical Intermediate (2009)

19 Radiolytic Synthesis of ultra small ZnS nanoparticles H 2 O g eaq H3O, H, OH, H 2, HOCH, H O 2CH 2SH H SCH 2CH 2OH H a b 2 nm HOCH2CH2SH OH SCH 2CH2OH H2O 2( SCH 2 CH2OH) aq ( HOCH2CH2S) 2 HOCH 2CH 2SH eaq CH 2CH 2 OH HS 2 Zn e aq Zn 2 Zn HS ZnS H 20 nm Very small ZnS nanoparticles compared to those prepared by chemical methods A.H. Suici et al. Chem. Phys. Lett. 2006, 422, 25.

20 Metal nanoparticles induced on supports

21 Ag-modified TiO 2 g Ag + solution + TiO 2 AgNPs@TiO 2 20 nm Diffuse reflectance spectra of pure and Ag-modified TiO 2 (P25)

22 Surface modification of TiO 2 : Decrease of electron-hole recombination Ag Ag Ag Ag Ag NPs act electron scavengers Enhancement of the photocatalytic activity under solar light Antibacterial properties

23 Direct Alcohol Fuel Cells - Portable electronic devices - fuel cells vehicules Direct Methanol Fuel Cells: Platinum based electrocatalysts are the most efficient Ethanol as a fuel: less toxic than methanol can be produced in large quantities from agricultural products Pd: very active for ethanol oxidation in basic medium much cheaper than Pt and 50 times more abundant

24 Self-assembly of surfactants on carbon nanotubes (CNTs) Carbon Nanotube Functionalization Mioskowski, C. et al Science 300, 775, N. Mackiewicz et al., J. Am. Chem. Soc., 130, 8110, N + Cl Collaboration with E. Doris and N. Mackiewicz, CEA, Saclay

25 Pd/CNTs: application in fuel cells Pd II Reduction by electron beams (dose rate: 2200 Gy s -1 ) Electrocatalysts for ethanol oxidation (111) (200) (220) (311) Curant Intensity : 25 times higher (3540 ma cm 2 mg 1 ) than the best intensities reported in the literature N. Mackiewicz et al., J. Am. Chem. Soc., 130, 8110, 2008.

26 Metal nanostructures induced in hexagonal mesophases

27 Mesophases Hexagonal Contineous cubic Micellar cubic Lamellar Temperature Micelles Concentration in surfactant wt% Soft templates for nanomaterial synthesis 1D, 2D or 3D nanomaterials with new optical, electrical, magnetic, mechanical properties

28 Synthèse de nano-objets en mésophase - Radiolyse en milieu confiné Cyclohexane - Mésophase : matrices molles Mieux contrôler la croissance des nano-objets (structure 1D, 2D, 3D) Synthèse en phase aqueuse ou en phase non-aqueuse eau 5<D<35 nm + sel métallique Chem. Mater. 2009, 21, ; Chem. Mater. 2009, 21, New J. Chem. 2012, 36, Adv. Funct. Mater. 2012, 22, Communication INC:, En direct des laboratoires de l institut de chimie du CNRS (2012)

29 Pd Nanowires: Application in Ethanol Oxidation I / ma cm -2 mg -1 Synthesis in CTAB-based hexagonal mesophases Irradiation by electron beams st cycle 200 th cycle KOH 1M E / mv vs. Hg/HgO 1 M EtOH, 1 M KOH, 50 mv s -1 Complete Oxidation Reaction of ethanol: CH 3 CH 2 OH + 3 H 2 O 2 CO H e- Reactions in alcalin media: CH 3 CH 2 OH + 3 OH - CH 3 CO ads + 3 H 2 O + 3 e- OH - OH ads + 1 e- CH 3 CO ads + OH ads CH 3 COOH CH 3 COOH + OH - CH 3 COO- + H 2 O Pd nanowires: very efficient in ethanol oxidation Very stable with cycling Application in fuel cells G. Surendran et al., J. Phys. Chem. C., 2008, 112, 10740

30 Polymer nanostructures

31 Conducting polymers : EDOT Cryo-TEM g rays electrons Control of the Morphology PEDOT Radio-polymerization in a position Cryo-TEM HO. N 3. EDOT 50 nm 50 nm Globular Structures H bonds interactions Fibers: interactions byp-stacking Application as Sensors J. Phys. Chem. B 2012, 116, Radiat. Phys. Chem. 2013, 82, 44-53

32 Polymerization in the hexagonal mesophase Extraction of the PDPB polymer nanostructures (addition of ethanol+h 2 O) b Ar Ar 1,4-diphenylbutadiyne Ar = Phenyl group h polymerization * Ar Ar Ar Ar Ar Ar Poly(diphenylbutadiyne) (PDPB) n * The parameters of the hexagonal mesophase are not affected by the irradiation Ghosh et al. Nature Materials (2015) 14,

33 Polymerization in hexagonal mesophases g -polymerization 300 nm In bulk Polymer Nanowires of tunable diameters Application in photocatalysis Ghosh et al. Nature Materials (2015) 14,

34 Conclusion Radiolysis is a powerful method to synthesize metallic, semiconductor, polymer nanostructure sand composite materials Radiolysis is a powerful method to synthesize bimetallic nanoparticles and nanostructured materials of controlled composition, structure, size and shape Soft templates can be used as nanoreactors to design (2D and 3D) nanomaterials of different shapes Application catalysis, photocatalysis, electrocatalysis (fuel cells), sensors

35 Thank you for your attention

36 Acknowledgements Mehran Mostafavi (LCP, Univ. Paris-Sud) Jean-Louis Marignier (LCP, Univ. Paris-Sud) Isabelle Lampre (LCP, Univ. Paris-Sud) Jacqueline Belloni (LCP, Univ. Paris-Sud) Samy Remita (LCP, Univ. Paris-Sud) Christophe Colbeau Justin (LCP, Univ. Paris-Sud)