metal nanoparticles and nanomaterials: radiolytic...
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Metal nanoparticles and nanomaterials:
Radiolytic synthesis and applications
Hynd Remita
Laboratoire de Chimie Physique, CNRS-UMR 8000
Université Paris-Sud, Orsay
Radiolytic synthesis of metal clusters
H2O es-, H3O
+, H•, OH•, H2, H2O2
Selective reducing environment
• (CH3)2CH OH + H• (CH3)2C
•OH + H2
• (CH3)2CH OH + OH• (CH3)2C•OH + H2O
g, e-
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)
Cinétique de nucléation de clusters d’argent
Fast Kinetics Center Elyse
Reduction and nucleation processes studied by pulse radiolysis
e-aq + Ag+ Ag0
k = 4.8 x 1010 dm3 mol-1 s-1
Ag0 + Ag+ Ag2+
k = 8.5 x 109 dm3 mol-1 s-1
Ag2+ + Ag+ Ag3
2+ k = 2 x 109 dm3 mol-1 s-1
Ag32+ + Ag3
2+ Ag42+ + 2 Ag+
E. Janata et al., J. Phys. Chem., 98, 10888, (1994) E. Janata, J. Phys. Chem., 107, 7334, (2003)
pulse
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
Stabilization of metal clusters by ligands or polymers
Ligands (CO, EDTA, calixarenes…)
M. Mostafavi et al., Rad. Phys. Chem., 41, 453, (1993)
Polymers (polyacrylate) *
I. Lampre et al. to be submitted. steric effect -
- -
-
- -
-
-
-
Ag n
m+
STM image of blue silver clusters
Ag73+ or Ag8
4+ (stable in air)
Ag NP stabilized by calix[8]arene
Functional group having affinity for metal NPs
Dose rate effect on size distribution of silver clusters
0 10 20 30 40 500
5
10
15
electron beam
C6+
ion beam
g rays
Percen
tage o
f p
arti
cle
s
Diameter (nm)
0
10
20
30
40
50
60
70
Percen
tage o
f p
arti
cle
s
0
5
10
15
20
25
30
Percen
tage o
f p
arti
cle
s
2200 Gy s-1
200 Gy s-1
1.75 Gy s-1
(Aqueous solution : 2 10-3 M AgClO4 , 0.1 M PVA, 0.2 M 2-propanol)
H. Remita et al., Radiat. Phys. Chem, 72, 575 (2005)
Dose rate effect on cluster size distribution
The final size depends on the dose rate At higher dose rate smaller particles are obtained
Silver particles
M. Mostafavi et al., Collaboration with CLAL,
since 1989
Nanometric Particles
(Conducting Pastes for electronics)
300-400 nm
At high dose rate,
alloyed clusters are
obtained
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
J. Belloni, H. Remita in Radiation Chemistry, EDP Sciences, p97-116, 2008.
Dose rate effect on bimetallic nanoparticle structure: Au-Ag system
([AuIII] = [AgI] = 5 x 10-4 M, [PVA] = 0,1 M, l = 0,2 cm) Low dose rate: 3,8 kGy.h-1
Aun/Agn core-shell
High dose rate: 35 kGy.h –1
Ag-Au Alloys
J. Phys. Chem.B, 102, 4310 (1998)
Bimetallic nanoparticles
M/N bi-layered M-N Alloy
Synthesis of nanoparticles of controlled stucture and composition
Catalytic convertors, NOX removing (Pt, Pt-Sn)
Selective hydrogenations (Pd, Pd-Au, Pd-Ag)
Fuel cells: Methanol oxidation (Pt-Ru, Pt-Au)
Ethanol oxidation (Pd-Au)
Oxygen reduction (Pt-Co, Au-Fe)
H+ reduction (Pt, Au-Fe)
Application in catalysis and fuel cells
Ksar et al. Chem. Mater., 2009, 21, 3677. R. Doherty, J. Catal. 2012, 287 , 102.
Gold nanorods
50 nm
Gold nanorods
F. Kim et al., JACS, 2002, 124, 14316 C. J. Murphy et al., MRS Bulletin, 2005, 30, 349
Shift of the longitudinal plasmon band towards larger wavelengths with increasing the aspect ratio
PVA(H) + OH PVA + H2O
PVA(H) + H PVA + H2
2 PVA PVA-PVA (cross linking)
Formation of a hydrogel
Irradiation induces crosslinking of the polymer
Microtomie TEM montrant des NRs bien dispersés dans l’hydogel PVA
Au nanorods in PVA matrices
Polyvinyl Alcohol
Abidi, W. et al, J. Phys. Chem. C (2010) 114, 14794.
Formation of Nanofilms
X-ray radiation under grazing incidence (ESRF)
F. Muller et al., Langmuir, 20, 4791, 2004
X-ray
scattering
Incident
X-ray beam
nanofilm of Ag
x
monolayer of C 21H23-COOH (behenic acid) +
Adsorbed Ag+ ions
qin < qc 4,5 nm
slits
miror Langmuir
cuve
monochromator
Interaction of X-rays with the interface
Follow the evolution of the structure at the surface
Nanoparticles
(ligands, polymers)
Metal
Electrodes Micelles
Oxides, Carbon,
Semiconductors
Zeolites
Mesophases,
Mesoporous
Materials
Polymeric
Membranes
Carbon
Nanotubes
J. Belloni, H. Remita in Radiation Chemistry, EDP Sciences, p97-116, 2008.
Matériaux microporeux et nanoparticules métalliques:
Application aux domaines des Capteurs Chimiques
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)
a. b. c.
De la suspension colloïdale .... au film mince
Chemistry of Materials (2006), Sensors and Actuators (2007) Superlattices and Microstructures (2008) Research on Chemical Intermediate (2009)
22232 ,,,,, OHHOHHOHeOH aq
g
22222 HOHCHSCHHSHCHHOCH
OHOHCHSCHOHSHCHHOCH 22222
22222 )()(2 SCHHOCHOHCHSCH aq
HSOHCHCHeSHCHHOCH aq 2222
2
aqZn e Zn
2Zn HS ZnS H
Radiolytic Synthesis of ultra small ZnS nanoparticles
20 nm
2 nm a b
Very small ZnS nanoparticles compared to those prepared by chemical methods
A.H. Suici et al. Chem. Phys. Lett. 2006, 422, 25.
Ag-modified TiO2
20 nm
Diffuse reflectance spectra of pure and Ag-modified TiO2 (P25)
Ag+ solution + TiO2 AgNPs@TiO2
g
Surface modification of TiO2 : Decrease of electron-hole recombination
Ag NPs act electron scavengers Enhancement of the photocatalytic activity under solar light Antibacterial properties
Ag
Ag
Ag
Ag
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
Direct Alcohol Fuel Cells
- Portable electronic devices
- fuel cells vehicules
Self-assembly of surfactants on carbon nanotubes (CNTs)
Mioskowski, C. et al Science 300, 775, 2003. N. Mackiewicz et al., J. Am. Chem. Soc., 130 , 8110, 2008.
Carbon Nanotube Functionalization
Collaboration with E. Doris and N. Mackiewicz, CEA, Saclay
N+
6Cl
Pd/CNTs: application in fuel cells
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.
Electrocatalysts for ethanol oxidation
PdII Reduction by electron beams (dose rate: 2200 Gy s-1)
(111)
(200)
(220)
(311)
Mesophases
Micellar cubic
Contineous cubic
Lamellar
Micelles
Micellar cubic
Hexagonal
Concentration in surfactant wt%
Temperature
Soft templates for nanomaterial synthesis 1D, 2D or 3D nanomaterials with new optical, electrical, magnetic, mechanical properties
5<D<35 nm
Cyclohexane
eau + sel métallique
- Radiolyse en milieu confiné - Mésophase : matrices molles Mieux contrôler la croissance des nano-objets (structure 1D, 2D, 3D) Synthèse en phase aqueuse ou en phase non-aqueuse
Synthèse de nano-objets en mésophase
Chem. Mater. 2009, 21, 1612-1617; Chem. Mater. 2009, 21, 5170. New J. Chem. 2012, 36, 2135. Adv. Funct. Mater. 2012, 22, 4900. Communication INC:, En direct des laboratoires de l’institut de chimie du CNRS (2012)
Pd Nanowires: Application in Ethanol Oxidation
Complete Oxidation Reaction of ethanol:
CH3CH2OH + 3 H2O → 2 CO2 + 12 H+ + 12 e-
Reactions in alcalin media:
CH3CH2OH + 3 OH- → CH3COads + 3 H2O + 3 e-
OH- → OHads + 1 e- CH3COads + OHads → CH3COOH CH3COOH + OH- → CH3COO- + H2O
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
KOH 1M
-1000 -800 -600 -400 -200 0 200 400 600
-333
0
333
666
999
1332
1665
1998
2331
I / m
A c
m-2m
g-1
E / mV vs. Hg/HgO
1st cycle
200th
cycle
1 M EtOH, 1 M KOH, 50 mV s-1
Synthesis in CTAB-based hexagonal mesophases Irradiation by electron beams
Fibers: interactions byp-stacking Globular Structures H bonds interactions
HO. N3.
EDOT
50 nm
50 nm
Cryo-TEM Cryo-TEM
Control of the Morphology
EDOT PEDOT
g rays electrons
Conducting polymers :
Radio-polymerization in a position
Application as Sensors
J. Phys. Chem. B 2012, 116, 1467--81 Radiat. Phys. Chem. 2013, 82, 44-53
Polymerization in the hexagonal mesophase
The parameters of the hexagonal mesophase are not affected by the irradiation
Ghosh et al. Nature Materials (2015) 14, 505 – 511
Ar
Ar Ar
*
ArAr
Ar
Ar
*
Ar
n
1,4-diphenylbutadiyneAr = Phenyl group
Poly(diphenylbutadiyne)(PDPB)
h
polymerization
b
Extraction of the PDPB polymer nanostructures (addition of ethanol+H2O)
300 nm
g -polymerization
Polymer Nanowires of tunable diameters
Polymerization in hexagonal mesophases
Application in photocatalysis Ghosh et al. Nature Materials (2015) 14, 505 – 511
In bulk
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…