AJITHAKUMARI ZMCTE

1. SYNTHESIS, CHARACTERISATION,AND
PHOTOCATALYTIC STUDY OF
NEODIMIUM DOPED CERIUM OXIDE
NANOPARTICLE
BY
AJITHA KUMARI
ZM17EDPS02
PHYSICAL SCIENCE
ZAINAB MEMORIAL COLLEGE OF TEACHER EDUCATION
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2. OUTLINE
INTRODUCTION
OBJECTIVES OF STUDY
EXPERIMENTAL
RESULTS AND DISCUSSION
CONCLUSION
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3. OBJECTIVES OF STUDY
To synthesis CeO2 and Nd+ doped CeO2
nanoparticle in three different ratio
[(100:1),(100:2.5),(100:10)]
Characterisation of these synthesised sample
To compare the photocatalytic activity of
synthesised samples
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4. INTRODUCTION
Nanomaterial
 Nanomaterial is any substance that have critical
dimension on the scale 1-100 nm
 Reduction of size may change reactivity of the
chemical system
 Physical properties also changed due to the size
reduction
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5. Cerium oxide nanoparticle
 Cerium oxide is very active rare earth metal oxide
 It is nontoxic , stable ,abundant and inexpensive.
 They are pale yellow coloured compound having cubic flurite
structure in which each cerium site is surrounded by eight
oxygen site in FCC arrangement and each oxygen site has
tetrahedron cerium site.
 It is the most stable oxide of cerium
 It is used in solid oxide fuel, polishing materials, UV blocker and
filter, gas sensor, catalysis , etc.
 It can be synthesized by different method such as hydrothermal
method, sol-gel method, precipitation method, flame spray
pyrolysis etc. 5

6. Sol-gel method
• Sol-gel process is defined as formation of oxide
network through poly condensation of molecular
precursor in a liquid.
• It is used to synthesis thin film and powders.
• Advantages- high purity , homogeneity and flexibility
in introducing the dopants in large concentration,
ease of processing.
• It provide large degree of control over the
properties(size, morphology, surface area, pore size 6

7. Photo catalysis
• Photo catalysis is the combination of photochemistry
and catalysis.
• Photo catalyst is defined as material that is capable
of absorbing light , producing electron – hole pair
that enable chemical transformations of reaction
participant and generate its chemical composition
after each cycle of such interaction.
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8. Conduction band
Electron
Valence band
Band gap
3 – 3.2 eV
Hole
O2-. (Super oxide radical)
Organic
pollutants
CO2, H2O, NH4
+, NO3
–
CO2, H2O, NH4
+, NO3
–
(Hydroxyl radical) OH
Organic
pollutants
UV Light
Mechanism of photocatalysis
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9. procedure
28-30%NH4OH
Ce(NO3)3.6H2O Solution
Ce(OH)4
PRECIPITATION Dispersion
Ce(OH)4
PRECIPITATE
H2O
SOL
1.Synthesis of sol
Sol formation

10. 10
2.Doping
Nd(NO3)3
SOLUTION
sol
Doping
Hydrothermal
treatment
Fine powder

11. CHARACTERISATION TECHNIQUES
• X-RAY DIFFRACTION
• FT-IR SPECTROSCOPY
• THERMAL ANALYSIS METHODS
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12. RESULTS AND DISCUSSION
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13. 13
a)PXRD pattern of Undoped CeO2 synthesised (black)
and calcined (red)
b)PXRD pattern of Nd doped CeO2 (100:1) synthesised
(black) and calcined (red)
1) XRD

14. 14
c)PXRD plot of Nd doped CeO2 (100:2.5) synthesised
(black) and calcined(red) d) PXRD plot of Nd doped CeO2(100:10) synthesised
(black) and calcined (red)

15. • XRD pattern shows that crystalline structure of CeO2
is cubic fluorite structure.
• No additional peaks were observed which represent
any secondary phase in the sample when calcined.
• Reflection peaks are broad, indicating the crystal size
is small &it is in the range nanoscale
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16. 2.FT-IR SPECTRA
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a) FT-IR spectra of undoped CeO2 synthesised (black)
and calcined (red)
b) FT-IR spectra of Nd doped CeO2(100:1) synthesised
(black) and calcined (red)
3352.86
1627.14 666.7

17. 17
c) FT-IR spectra of Nd doped CeO2(100:2.5) synthesised (black)
and calcined (red)
d) FT-IR spectra of Nd doped CeO2(100:10) synthesised
(black) and calcined (red)

18. • Absorption peak in the range 2000-3400 cm-1 is assigned to
OH stretching vibration of H2O.
• Band due to the stretching vibration of Ce-O bond can be seen
below 700 cm-1.
• The band at 1630 cm-1 is due to the scissor bending of H-O-H.
• After calcination, band originated from the residual water
became weaker except Ce-O stretching mode
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19. 2.TGA/DSC
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a) TGA/DSC plot of undoped CeO2 b) TGA/DSC plot of Nd doped CeO2(100:10)
synthesised

20. • Weight loss percentage of sample decreasing
with increasing temperature, indicating the
thermal stability of sample.
• There is no strong endothermic or exothermic
peak which indicate absence of the phase
transition.
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21. PHOTOCATALYTIC ACTIVITY STUDY
• Photocatalytic activity of bare CeO2 and Nd +doped
CeO2 was studied by observing degradation of
methylene blue(10-5M).
• Methylene blue is blue colour when dissolved in water.
It turns colourless in presence of reducing agent.
• In presence of photocatalyst, it coverted into co2 and
water.
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22. 22
a) Absorption spectrum of methylene blue degradation
using undoped CeO2 synthesised b) Absorption spectrum of methylene blue degradation
using undoped CeO2 calcined
c) Absorption spectrum of methylene blue degradation
using Nd doped CeO2(100:1)synthesised
d) Absorption spectrum of methylene blue degradation
Using Nd doped CeO2(100:1) calcined

23. 23
e) Absorption spectrum of methylene blue degradation
using Nd doped CeO2(100:2.5) synthesised
f) Absorption spectrum of methylene blue degradation
Using Nd doped CeO2(100:2.5) calcined
g) Absorption spectrum of methylene blue degradation
using Nd doped CeO2(100:10) synthesised
h) Absorption spectrum of methylene blue degradation
Using Nd doped CeO2(100:10) calcined

24.  As time increases ,the concentration of dye decreases in
presence of photocatalyst
 Doping in ceria increases the activity of catalyst
 Higher ratio of dopant has shown higher photocatalytic
activity
 Sample containing Nd in the ratio (100:10) has more
photocatalytic activity
 Calcination has no significant effect on dye degradation
 Nd can act as electron and/or hole traps. The trap of charge
carrier can decrease the recombination rate of electron -hole
pair and increases its life time ,thereby increases the
photocatalytic activity
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25.  CeO2 and Nd doped CeO2 has been synthesised via sol-gel method
 Characterised using XRD,FT-IR spectroscopy, TGA/DSC analysis.
Photocatalytic activity also studied
 XRD pattern reveals the crystalline structure of ceria is cubic flurite
structure
 It does not underdo any phase transformation on calcination
 FT-IR spectra shows that band in the range 2000-3400 cm-1is due to the
stretching vibration of OH group from physically adsorbed water
molecules.
 Band due to the stretching vibration of Ce-O bond can be seen below 700
cm-1 25
CONCLUSION

26.  Sample containing higher ratio of dopant has more
photocatalytic activity.
 It is due the delay in recombination of electron-hole
pair
 TGA/DSC analysis shows the sample stability as well
as absence of phase transformation.
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CONCLUSION

27. THANK YOU
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