SEMINAR on Nanocomposites

7/30/2019 SEMINAR on Nanocomposites

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By

Sudheer Kumar Yadav

Nanocomposites

andits Applications


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Nanoparticle

The particle having at least one dimension sized between 1 -100 nanometers.

Nanocomposite

A multiphase solid material where one of the phases must be in nano range.

(a) FESEM (b) HRTEM and TEM (inset) images of the ZnO/Cu nanocomposite.

C .Yang et al. Langmuir 2012, 28, 45804585

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1)Multifunctional Properties

Fe3O4@nSiO2@mSiO2@Au core-shell-nanocomposite

Ordered mesoporous

High magnetization

NIR absorption (photo thermal therapy)

TEM image of the Fe3O4@nSiO2@mSiO2@Au nanocomposite

Importance of the Nanocomposites

Z. Xu et al. J. Phys. Chem. C 2010, 114, 1634316350

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2) For enhancing the physical Properties of

the NanoparticlesMechanical

Electrical

Thermal

Optical

Electrochemical

Catalytic

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Nanocomposites

Ceramic

MatrixNanocomposites

Metal

MatrixNanocomposites

Polymer MatrixNanocomposites

Different Types of Nanocomposites

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Ceramic-matrix nanocomposites

Main part of volume is occupied by a ceramic.

SiC, Al2O3, B4C, ZrO2, etc are the examples for the ceramics.

Dispersion of metal, metal oxide nanoparticles etc. onto the matrix.

Improved mechanical properties, hardness and fracture toughness.

SEM image of Al2O3/SiC nanocomposite

P H C. Camargo et al. Materials Research, Vol. 12, No. 1, 1-39, 2009

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Consists of a ductile metal or alloy matrix.

Dispersion of metallic or ceramic nanoparticles onto the matrix.

Materials with high strength in shear/compression processes and high

service temperature capabilities can be produced.

Potential applications in aerospace, automotive and development of

structural materials.

TEM image of Fe/MgO nanocomposite.

Metal-matrix nanocomposites

Y. H. Choa et al. Journal of Magnetism and Magnetic Materials 266 (2003) 2027

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500 nm1m


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Incorporation of metal and ceramics into the polymer matrix.

Improved mechanical properties, increased heat and impactresistance can be achieved by filling different organic andinorganic nanoscale materials.

Also exhibits magnetic, electronic, optical or catalytic properties.

TEM images of SiO2/polystyrene nanocomposite particles

olymer-matrix nanocomposites

H. Zou Et al. Chem. Rev. 2008, 108, 38933957

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Homogenous precipitation

Chemical reduction

Hydrothermal synthesis

Sol gel

Thermal decomposition

anocomposites Different Synthetic Method

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omogenous precipitation

NH4HCO3 (14 ml)

Centrifuged

i) Addition of 100 ml H2O

Cu (1.5 g)

Cu2(OH)2CO3 / Ag2CO3

Ag2CO3 (0.15 g) Conc. NH3 (4.5 ml)

Stirring at RT

Dried in vacuum oven at 75o

C for 10 h

Deep blue complex

Precipitate

Turbid solution

ii) Heated

Calcined at400oC (1.5h)

S. Wang et al. Materials Chemistry and Physics 108 (2008) 165169

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TEM image of Ag / CuO nanocomposite

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Mechanism for the formation of Ag / CuO nanocomposite

S. Wang et al. Materials Chemistry and Physics 108 (2008) 165169

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1 wt. % HAuCl4

solution (1mL)MWCNT (1mg)

MWCNT-Au nanocomposite

i) Sonicated for 5min

ii) Addition of 100 ml H2O

iii)Heated to boiling

iv)Sodium citrate (1.5mL)

Chemical reduction

F. J. Xiao Mater. Chem., 2012, 22, 7819-7830

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ematic representation of Au Coating on MW

MWCNT Dispersed MWCNT

Au nanoparticles coated MWCNT

1oo nm


Sonication

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Hydrothermal Synthesis

TiCl4 EtOH (10 ml)

Transparent Solution

ZnCl2 H2O (10 ml)

ZnO-TiO2 nanocomposite

Molar ratio

Zn : Ti

1:1

1:2

2:1

Stirring at RT

Addition of 10 ml Urea (0.6 M)

ii) Centrifuged, washed and calcined

at 450oC for 2h

i) Heated in autoclave at 180oC for 16 h

D. Chen et al. J. Phys. Chem. C 2008, 112, 117-122

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Pb (Ac)2C3H8O3 HNO3

Stirred at RT

Sol

Dried at RT gelation

Gel

Calcined at 550oC for 2h

PbO / SiO2 nanocomposite

TEOS

Molar Ratio

TEOS:H2O:C3H8O3:HNO3:HAc:Pb(Ac)2

1:20:1:0.02:1:0.04

Sol gel

HAcH2O

T. Zhou et al.Anal. Chem. 2010, 82, 17051711

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Applications

OfNanocomposites

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Nanocomposites

Photocatalysis

Biosensors

Catalysis Gas sensors

Energyconversion and

storage

Opticaldevices

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Biosensors

Pt-CNT nanocomposites --> glucose biosensors.

Glucose biosensors are based on GOD enzymatic reaction.

GOD identifies glucose target molecule quickly and accurately .

Electrochemical determination of liberated H2O2 using

Pt-CNT-GOD Electrode.

Detection limit is 0.oo5 mM of glucose concentration.

Reusable

Z. Wen et al.J. Phys. Chem. C 2009, 113, 1348213487

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Typical current-time response curves of the Pt-CNTs-GOD electrode.

Biosensors

Z. Wen et al.J. Phys. Chem. C 2009, 113, 1348213487

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Optical Devices ZnO-CdS nanocomposite

Light emission from UV to visible (upto green)

by changing the composition of nanocomposite.

Absorption spectra and optical band gap of ZnOCdS nanocomposite.

L. Irimpan et al. Sci. Adv. Mater. 2010, 2, 117137,

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Nonlinear absorption coefficient and nonlinear refractive index increase

for the composite.

Significant optical limiting performance.

Optical Devices

Laura L. Beecroft Chem. Mater. 1997, 9, 1302-1317

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Catalysis CoAl2O4/-Al2O3nanocomposite

High surface area and have surface hydroxyl group

Active catalyst for the decomposition of H2O2

Oxidize a wide range of organic and inorganic pollutants

Metal oxide catalyzed Decomposition of H2O2

A. Dandapat et al. ACS Appl. Mater. Interfaces 2012, 4, 228234

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Photos of (a) CoAl2O4/-Al2O3 composite nanopowder and (b) 5 wt.%

dispersion of (Co : Al=1:5)/500 C in glycerol; c) UVvisible absorptionspectrum of above (b)

Self cleaning pigment

Reusable catalyst

Stable

A. Dandapat et al. ACS Appl. Mater. Interfaces 2012, 4, 228234

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Photocatalytic Activity

Au nanoparticle functionalized TiO2 nanotube array nanocomposite

Degradation of organic dye pollutant (e.g. Methyl orange) under UV light.

Au doped TiO2 act as efficient electron trap for photogenerated electrons.

Facilitates efficient separation of photogenerated e- & h+ .

Holes react with H2O to generate OH radical and other active species.

Dye + OH Dye + H2O (decolorization of methyl orange)

Dye + Dye DyeDye (recombination of carbon-centered radicals)

Dye + OH H2

O + CO2

(mineralization)

Mechanism


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Mechanism for the liquidphase photocatalytic degradationof organic dyes


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Gas sensors

PbO/SiO2 nanocomposite

Sulfide sensor based on room temperature phosphorescence (RTP).

Phosphorescence intensity of the composite is quenched by sulfide.

pH 11 is found to be good working condition.

Detection limit for sensor is estimated to be 0.138 M.

Color of sensor and its phosphorescence intensity change with continuous

addition of sulfide and could be observed by naked eye.


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(1a) RTP photograph of PbO/SiO2 composite at different concentrations of Na2S.

(1b)Photograph of PbO/SiO2 composite at different concentrations of Na2S.

(2a) RTP photograph of PbO/ SiO2 composite before and after interaction with H2S.

(2b) Photograph of PbO/SiO2 composite before and after interaction with H2S.

0 M 50 M 200 M 500

M


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Proposed Phosphorescence Quenched andRecovered Mechanism for the Sulfide SensorBased on PbO/SiO2 Composite


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Conclusions

Multifunctional properties can be achieved.

Physical properties can be enhanced compared to the pure

components.

Can be synthesized by various chemical methods e.g. sol gel,

homogeneous precipitation , chemical reduction, hydrothermal

synthesis etc.

Potential applications in catalysis, photocatalysis; used as bio sensors,

optical devices, gas sensors etc.

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