Figure 5.8 (a) Voltage vs time plot of CdS QD solar cell with TiO2 photoanode (b) Voltage vs time plot of Hg-doped CdS sensitiser with GO dopedTiO2 Photoanode.
SYNTHESIS AND CHARACTERIZATION OF NICKEL AND ZINC FERRITES BY USING UREA AS A FUEL R. Deivakumarana, N. Dharumanb , S.K. Suresh Babua, Dr. L. John Berchmansb,*, a b
Department of Nanoscience and Technology, Karunya University, Coimbatore.
Electropyrometallurgy Division, CSIR-Central Electrochemical Research Institute, Karaikudi, India.
ABSTRACT The magnetic materials are found applications which include High density data storage, Targeted drug therapy, Magnetic Resonance Imaging (MRI), Power generators, Magnetic sensors .
potential
CHARACTERIZATION-XRD ANALYSIS Figure 1 shows the XRD patterns of the nanostructured samples S1, S2, S3, S4, S5, S6. .
EDS ANALYSIS Figure 3 shows Energy Dispersive X-ray Spectroscopy (EDS) of Zn doped Nickel Ferrite. cps/eV
12
10
8
Ni O Zn Fe
Fe
Ni
Zn
6
Spinel ferrites (AB2O4, A=M2+,B=Fe3+)
4
2
Microstructure, Distribution of divalent and trivalent cation in octahedral [B], tetrahedral [A] sites respectively.
0 2
4
6
keV
8
10
12
14
Elemental composition of ferrites. THEROGRAVIMETRIC ANALYSIS
INTRODUCTION Nickel Ferrite (NiFe2O4) inverse spinel (D1-x Tx) [Dx T1+x] O4 Zinc Ferrite (ZnFe2O4) normal spinel (D) [T] O4
Single phase spinel structure. The planes (220) and (440) are cation on tetrahedral sites. The (400) plane cation on octahedral sites . Sampl e No
COMBUSTION SYNTHESIS Methods of synthesis Co-precipitation, Sol-gel method, Hydrothermal method , Combustion synthesis . Combustion reaction method Nanometric particle sizes Good crystallinity, Monophases. Advantages Easy, Safe, Fast . Reproduction in large scale. Final characteristics of the particles Time of combustion Operating temperature Driving force -energy released during the burning
Formula
Doping Lattice Space Crystalli Concentr JCPDS Shape Paramete Group te size ation r
S1 NiFe2O4 S2 NiFe2O4 Ni1S3 xZnxFe2O4 Ni1S4 xZnxFe2O4 Ni1S5 xZnxFe2O4 S6 ZnFe2O4
0.25 0.5 0.75
01-0742081 01-0862267 00-0520277 00-0520278 00-0520279 01-0860508
a (A°)
t (nm)
Cubic Fd-3m
8.3312
70
Cubic Fd-3m
8.3246
61
Cubic Fd-3m
8.3412
38
Cubic Fd-3m
8.3577
47
Cubic Fd-3m
8.3782
84
Cubic Fd-3m
8.4295
70
SEM ANALYSIS
A B
Gases like NO2 ,CO2 , NO are released . RESULTS AND CONCLUSION Nanostructured NiFe2O4 and ZnFe2O4 Thermal decomposition of nitrate salts
Particle size, phase purity, crystalline structure are studied using X-ray diffraction (XRD). Average crystalline size -Debye-Scherrer equation. Surface morphology and elemental composition are analyzed using (SEM) and (EDS).
NiFe2O4
Urea
Varying the amount of fuel (urea)- Properties can be tuned. Zn doping in different concentrations (0.25, 0.5, 0.75, 1) – to tune the properties.
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Variation of slope in TGA curve shows the combustion products.
Varying concentrations of urea as a fuel.
Ni(NO3)2
Fe(NO3)3
Figure 4 shows the TGA curve of NiFe2O4 Exothermic reaction
Figure 2 shows scanning electron micrographs Changes in microstructure with doping of Zinc . The pores and voids present in the sample are due to release of gases during combustion.
REFERENCES 1. S.M. Patange, S.E. Shirsath, et al, Phys. Status Solidi A 209, No 2 , 347-352(2012). 2. J Jacob, M. Abdul Khadar, J. Appl. Phys 107, 114310(2010). 3. H. Kavas, A. Baykal, et al, J. Alloys. Compd 479 (2009) 49-55. CONTACT Contact :* Correspondence author: E-mail address: ljberchmans@gmail.com (Dr. L. John Berchmans)