Synthesis and Characterisation of Nano crystalline Cerium Nickelate ...

International Journal of ChemTech Research
CODEN( USA): IJCRGG ISSN : 0974-4290
Vol.4, No.2, pp 798-804, April-June 2012
Synthesis and Characterisation of Nano crystalline
Cerium Nickelate (CeNiO3) Powders using Low
Temperature Molten Salt Technique
S. Ignatius Arockiam 1 *, A. Peter Pascal Regis 1 , L. John Berchmans 2
1 Department of Chemistry, St. Joseph’s College, Tiruchirappalli - 620 002,
Tamil Nadu, India
2 Electropyrometallurgy Division, CSIR-Central Electrochemical Research Institute,
Karaikudi-630 006,Tamil Nadu, India
*Corres. author : ignatiuschem@gmail.com
Abstract: The ultrafine bimetal ternary oxide (CeNiO3) powders have been prepared by molten flux
method using oxide precursors. The synthesized materials were characterised using XRD, FTIR, CHNS,
EDAX and EPR techniques.The morphology of the synthesized crystals were scrutinized using Scanning
Electron Microscopy(SEM). The XRD analysis has shown that the synthesized crystal has possessed
cubic structure. FTIR spectrum exhibits the absorption bands for the O-H stretching vibration and Ni-O
bands at different wave lengths. The CHNS analysis presents the impurities level in the synthesized
compound. EDAX analysis gives the concentration of Ce, Ni and O in the compound. The lone pair of
electron state is identified from the EPR spectrum. The SEM micrographs have shown the presence of
fine crystallites with irregular morphology. The average particle size of the powders is ranging between
25-35 μm. From the above studies, it has been concluded that pure crystals of CeNiO3 compound can be
synthesized by low temperature molten salt technique.
Keywords: Molten Salt Synthesis, Cerium Nickelate, XRD, FTIR, SEM.
Introduction
Perovskite ABO3 materials are of worldwide
interest because of their very interesting properties,
such as ferroelectric, magnetic, optical and colossal
magnetoresistance [1], high-Tc superconductivity [2],
non-volatile memory effects [3]. Their crystal structure
consists of corner sharing BO6 octahedra with the A
ion in a high co-ordination site. The relative ionic radii
of A m+ or B n+ (m+n=6) give rise to ‘distorted’
perovskite structures with cubic symmetry. A variety
of transition and non transition metal ions can be
substituted either fully or partially in A and B sites.
This gives rise to an extraordinary range of phenomena
such as ferroelectricity, superconductivity, high
temperature ionic conductivity, a variety of magnetic
ordering etc [4].
In recent years cerium-based catalysts have
been investigated since they find potential applications
for the treatment of exhaust gas from automobiles to
their use in methanol formation [5,6] the water gas
shift reaction [7,8] acetone hydrogenation, alkadiene
hydrogenation [9] and catalytic oxidation of CO[10]
and of light hydrocarbons [11-13]
Nanosized metal oxide particles can be
synthesised by a variety of methods, including
chemical gas phase growth methods such as chemical
vapor deposition (CVD), sol-gel processing and
reverse micelle,[14] laser pyrolysis[15] self-assembly
templating[16], electrochemical synthesis [17] metal-

S.Ignatius Arockiam et al /Int.J. ChemTech Res.2012,4(2) 799
organic chemical vapor deposition (MOCVD),
molecular beam epitaxial, and plasma synthesis
[18,19]. Molten salt synthesis is one of the most
versatile techniques to prepare highly ordered complex
oxide materials. The molten salts are used as the
reaction medium for the reactants dissolution and
product precipitation. Studies have shown that the
products obtained from molten salts are affected by the
synthesis conditions, such as the type of salt used, the
annealing temperature, the temperature ramp rate, the
precursor composition, and the solubility of the
reactive constituents in the molten salt etc, [20-22 ].
The molten salts rendered homogeneous
distribution and high intimacy of the reactive
components at the atomic scale in the initial mixture of
precursor salts. Hence, the diffusion distance and the
rate of the reactive species in molten melts are
modified and an efficient material transport is enabled
to meet the minimal kinetic requirement for the
reaction [23-25].
Generally the starting materials for molten salt
synthesis are inorganic compounds such as sulfates,
chlorides and oxides, which are blended with the alkali
metal nitrates, chlorides, carbonates, hydroxides as a
powder mixture before heating to the reaction
temperature. Many complex oxide materials have been
synthesized by molten salt technique [26-29].
Even though, many soft chemical routes have been
attempted, only few studies have been made on the
CeO2
NaCl/KCl Flux
synthesis of CeNiO3 compounds using molten flux
method. Hence, an attempt has been made on the
preparation of CeNiO3 by this method.
Experimental work
Reagent-grade chemicals like cerium oxide
(CeO2), nickel oxide (NiO) were used as the starting
materials. They were obtained from Merck India Ltd,
Bombay. Appropriate amount of chloride salts such as
sodium chloride (NaCl) and potassium chloride (KCl)
were used as the flux. They were thoroughly ground
using a mortar and pestle and were placed in a high
density alumina crucible. The mixture was then heated
in an electrical resistance furnace at 900 0 C for 12 hrs.
The heating rate was 200 °C per hour for all the
experiments.The resulting reaction mixture was cooled
to ambient temperature and it was washed with hot
water for several times. The unreacted cerium, nickel,
alkaline salts were removed by treating with these
solvents. The residual powders were dried in a vacuum
oven at 50 °C for 1 hour and cooled to room
temperature. The method of synthesis is presented in
the form of a flow chart and shown in fig.1. Finally
free flowing fine powders were obtained and they were
characterized for their physicochemical properties.
Mixed and placed in Alumina crucible
Thermal treatment at 900 0 C
Washing with hot water
Dyring in hot air oven
Fine crystalline CeNiO3
Fig-1: Flow chart for the preparation of CeNiO3 compound.
NiO

S.Ignatius Arockiam et al /Int.J. ChemTech Res.2012,4(2) 800
The purified powders were characterized by
XRD (Philips 8030 X-ray diffractometer) to identify
the phase purity of the compound. The unit cell lattice
parameters were obtained by the Least-square fitting
method of the d-spacing and the hkl values. Fourier
transform infrared (FTIR) Spectroscopy was used to
study the structure coordination of the calcined
powders using Perkin Elmer UK paragon-500
spectrophotometer. To record the spectrum, each
sample was mixed with KBr, ground in to fine powder
and made into pellet. It was then examined in the
wave number ranging from 400-4000 cm−1. The
elemental composition of the synthesized powders was
determined using an Atomic absorption spectroscope
(AAS) Varian Spectra 220 spectrophotometer. Carbon,
hydrogen, nitrogen, and sulphur contents of the
samples were assessed using an Elemental analyzer
Vario EL III-Germany Instrument. Electron spin
resonance (ESR) spectral analysis was performed
using microwave frequency 9.857403 GHz with fields
corresponding to about ~ 6500.000G sweep width
using a Bruker Bio Spin Gmbh EPR spectrometer. The
morphology of the synthesized powders was examined
by a Scanning Electron Microscope (SEM)-JSM-3.5
CF, Japan JEOL make.
counts
12000
10000
8000
6000
4000
2000
0
28.62
33.14
37.32
43.36
47.56
56.4
62.9 69.48
20 30 40 50
Position (2Q)
60 70 80 90
Fig.2 : X-ray diffraction profile of the CeNiO3
Results and Discussion
X-Ray Diffraction studies
The XRD data of the synthesized crystals are
presented in Fig.2. The lattice constant values are
determined using the equation,
1/d 2 = h 2 +k 2 +l 2 /a 2
All the XRD peaks are indexed assuming a
cubic structure. The calculated lattice
parameter values are in good agreement with the
reported values. The d spacing values of calcined
powders are well matched with the XRD pattern of
CeNiO3. The average crystallite size of the products
was determined from the XRD patterns according to
the Scherrer’s equation D = 0.9λ / βcosθ. The average
crystallite size is ranging between 85-100nm.
Fourier transform infrared (FTIR) spectroscopical
analysis
FTIR spectrum recorded for the cerium
nickelate compound and presented in Fig-3. The
transmittance band appeared at 3434 cm -1 may be
attributed to the O-H stretching vibration of water
molecules as reported in the literature [30]. The bands
seen between 1456 to 1639 cm -1 are related to the
coordination of the Ni 3+ cations as reported by Fernades
et al. [31].The transmittance bands in the wave length
region of 3434-3404 cm -1 are responsible for the
formation of the single phase CeNiO3compound. The
bands noticed at higher wavelength region may be
assigned to the Ni-O bands.

S.Ignatius Arockiam et al /Int.J. ChemTech Res.2012,4(2) 801
Transmittance [%]
20 40 60 80 100
3912.21
3743.13
3500
3434.58
3500
3000
3000
2924.76
2857.15
2500
2500
2000
2000
Wavenumber cm-1
Fig-3 FTIR spectrum of CeNiO3 compund.
Carbon, hydrogen, nitrogen and sulfur (CHNS)
analysis
The results on the CHNS analysis are
presented in Table.1. From the table, it is noticed that
the compound has associated with some minor
impurities such as C, H and S.
Table 1: Chemical analysis of the compound of
CeNiO3.
compound C (%) H (%) N (%) S (%)
CeNiO3 0.045 0.195 0.000 0.040
Table.2: EDAX analysis data
1736.09
1639.80
1500
1456.75
1500
1162.18
1000
1000
727.53
500
536.53
458.49
500
20 40 60 80 100
Energy dispersive X-ray analysis (EDAX)
The elemental analysis of the synthesized
compound was performed using energy dispersive xray
analysis technique . Fig.4. represents the EDAX
profile of Ce, Ni and O of the synthesized CeNiO3
compound. The results on the EDAX analysis are
presented in Table.2. The spectrum exhibits the
constituent elements are in appropriate wt%.
Compound Ce (wt%) Ni (wt%) O (wt%)
CeNiO3 60.09 27.51 12.41

S.Ignatius Arockiam et al /Int.J. ChemTech Res.2012,4(2) 802
Fig-4 EDAX profile of Ce, Ni, and O in CeNiO3
Electro paramagnetic resonance (EPR) studies
The paramagnetic resonance spectrum of the
CeNiO3 is presented in Fig.5. From the EPR spectrum,
it is noticed that the value of g factor is g=2, which
represents the paramagnetic entities present in the
parent compound. The lone pair electron state is
identified from the spectrum. It is also revealed that
the position of the signal is very close to the value
expected for uncorrelated spins with the gyromagnetic
factor Ce 4+ - Ni 2+ dipolar interactions.
Intensity
0.2
0.0
-0.2
-0.4
-0.6
-0.8
-1.0
0 1 2 3 4 5 6 7 8 9 10 11 12 13 14
g- factor
Fig-5 EPR spectrum of CeNiO3compound
Ultra-violet spectroscopic studies
Fig. 6. shows the UV-Visible spectrum of the
synthesized CeNiO3 compound. A broad absorption
band is noticed at 390 nm in the spectrum represents
the Ni-O and Ce-O absorption bands. From the
spectrum, the band gap of the material is determined
using the formula E = hʋ and found to be 3.18 eV.

S.Ignatius Arockiam et al /Int.J. ChemTech Res.2012,4(2) 803
R (%)
1.2
1.1
1.0
0.9
0.8
0.7
0.6
0.5
0.4
200 300 400 500 600 700 800
Wavelength (nm)
Fig-6 UV-Visible spectrum for CeNiO3 compound
SEM analysis
The morphological features of the synthesised powders
were obtained by means of scanning electron
microscopy. Fig-7(a) and 7(b) show the scanning
electron micrographs of CeNiO3 compound obtained
Fig- 7(a) and 7(b) SEM image of CeNiO3
(a) (b)
by Molten Salt Synthesis (MSS) route. The crystals
have shown an assorted particle morphology. The
average particle size of the powders is ranging
between 25-35 μm.

S.Ignatius Arockiam et al /Int.J. ChemTech Res.2012,4(2) 804
Conclusions
Fine crystalline CeNiO3 powders are
successfully synthesized using low temperature molten
salt technique. The XRD analysis confirms that the
compound has the cubic structure. FTIR spectrum
reveals the Ce-O, Ni-O band positions in CeNiO3
compound. CHNS analysis shows the compound has
minor impurities such as carbon, hydrogen and
sulphur. From the UV reflectance spectrum, the band
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