Research Journal of Recent Sciences ________________________________________________ ISSN 2277-2502
Vol. 1 (ISC-2011), 202-206 (2012)
Res.J.Recent Sci.

Synthesis, Characterization and Hydrophilic Properties
of Nanocrystalline ZnFe2O4 Oxide
Bangale Sachin and Bamane Sambaji
Department of Chemistry, Dr. Patangrao Kadam Mahavidyalaya, Sangli, MS, India

Available online at, www.isca.in
(Received 10th September 2011, revised 16th January 2012, accepted 28th January 2012)

Abstract
This study reports on synthesis of nano sized mixed oxides ZnFe2O4 was prepared by novel self combustion method using urea as a
fuel. The processing features and the micro structural characteristics of ZnFe 2O4 phases formed during self combustion reaction of
the gels have been investigated by TG-DTA, SEM, XRD, and EDX and TEM. It has been found that the nanoscale composite
powders of ZnFe2O4, directly obtained through the in situ self combustion reactions within the gel are composed of loosely
agglomerated particles with sizes of ~100 nm, while these particles themselves are the aggregates of finer ZnFe 2O4 and crystallites
of 22- 32 nm in size. The densities of sintered oxides evaluated by different methods are a,roximately same. The superhydrophilicity
of the sintered oxides was investigated by wetting experiments, by the sessile drop technique, were carried out at room temperature
in air to determine the surface and interfacial interactions.
Keywords: XRD, combustion method, nanomaterial, znfe2o4.

Introduction
Recently, nanostructures like nanowires, nanobelts and
nanodiskettes, have gained a considerable attention due to
their potential in the development of smart functional
materials, devices and system1. Sensors for biotechnological,
industrial, environmental, food pharmaceutical, medical and
related a, lications. Optical sensors for oxygen have been
used for noninvasive analysis of dissolved oxygen in shake
flasks for cell cultures. The oxygen sensitive element is a
thin, luminescent patch affixed to the inside bottom of the
flask. Both intensity and decay time may be measured 2,3.
Unlike, optical and electrochemical sensors. Solid state gas
sensors based on semiconductors metal oxides may be a
promising alternative, since them after good sensors
properties and can be easily mass produced. Several
semiconducting metal oxide viz. La-doped SnO24,5, BaTiO3.
It is well known that the semiconducting oxides such as ZnO,
SnO2, Fe2O3, Ga2O3, Sb2O36.7. Are sensitive to toxic and
inflammable gases. Among the chemical sensors LaCoO3,
BaTiO3, LaFeO3, LaMnO3 etc. are perovskite-type materials
of general formula ABO3 are extensively studied owing to
their notable gas sensitivity for different poisonous gases in
addition to their magnetic, catalytic and other physical
properties. The perovskite-type metal oxide including the dblock and rare earth elements has attracted the attention of
many researchers due to their homogeneity, interesting
structural, catalytic and gas sensing properties. There is an
increasing interest in finding new materials in order to
develop high performance solid state gas sensors. Gas
sensors are important in environmental monitoring home
safety and chemical controlling. Many different
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semiconducting oxides in bulk ceramic8.9, thick film10 and
thin film11.12. Form have been studied as a candidate sensor
element for gas sensing, spinel-type oxide semiconductors
(ferrites) are an alternative for inexpensive and robust
detection system because of good chemical and thermal
stability under operating conduction. The sensing mechanism
consists in the change of electrical resistivity resulting from
chemicals reaction between gas molecules and the metal
oxide surface13,14. The surface morphology has an essential
role on the sensitivity of solid-state sensors. The nanograined
materials offer new o,ortunities for enhancing the
performance of gas sensors because of their high surface to
volume ratio15,16. Several studies have reported that by finely
controlling the micro/nanostructure or chemical composition
of a surface, the adhesion between the superhydrophobic
surface and water can be changed. Such superhydrophobic
sur-faces show potential in a variety of a,lications from
antisticking, anticontamination and self cleaning to
anticorrosion and low friction coatings and gas sensing17-20.
In this paper a sol-gel self combustion method was a,lied to
prepare nanostructured zinc ferrites. The rapid heating and
cooling during self combustion reaction can produce
materials with high specific surface area which is beneficial
for Hydrophilic test.

Material and Methods
In this study, ZnFe2O4 powder was synthesized by solution
combustion technique using the starting regents as
Zn(NO3)26H2O (7.43g), Fe (NO3)26H2O (7.27g) and urea
(6.05g) as a fuel. urea possesses a high heat of combustion. It
is an organic fuel providing a platform for redox reactions
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Research Journal of Recent Sciences _____________________________________________________________ ISSN 2277-2502
Vol. 1 (ISC-2011), 202-206 (2012)
Res.J.Recent Sci.
during the course of combustion. Initially the zinc nitrates,
iron nitrates and urea are taken in the 1,1,4 stoichiometric
amount and homogenous paste was made. The paste formed
was evaporated on hot plate in temperature range of 70 to
800C to result into a thick gel. The gel was kept on a hot
plate for auto combustion and heated in the temperature
range of 170 to 1800C. The nanocrystalline ZnFe2O4 powder
was formed within five minutes. The powder was sintered at
300, 500, 800, and 10000C for 4 hr. which resulted in to a
brown color shining powder.

Results and Discussion
TG-DTA analysis: TG-DTA analysis was performed at a
heating rate of 10 K min-1 to investigate the thermal
properties of. ZnFe2O4. The TG spectrum and its 1 st
derivative in figure-1 show the thermal decomposition of
ZnFe2O4 is the curve indicates that the slight weight loss in
ZnFe2O4 powder due to little loss about 14.66 at temperature
up to 2000C in ZnFe2O4 of moisture, carbon dioxide and
nitrogen gas. The DTA curve of ZnFe2O4 recorded in static
air and in shown in figure-1.
The curve shown that ZnFe2O4 did not decompose, but
weight loss was due to dehydrogenation, decarboxylation
and denitration. Further weight loss of about 16% between
the temperature range 4000C and continuous loss in weight
about 33.33% up to 5500C is attributed to loss of organic
materials and yield final product at 6000C, this weight loss
and weight gained was very negligible. This weight change
was in the range of 8000C these indicating that the
synthesized powder was almost stable from the begging. The
formation temperature in the present work is found to be
comparatively similar than that reported for corresponding
solid state reaction route.

X-ray Diffraction analysis: The X-ray diffraction pattern of
ZnFe2O4 powder is shown in figure- 2. The observed d
values compared with standard d values and are in good
agreement with standard d value JCPDS data card number
82-1042. The structure possesses the cubic may be attributed
to the different preparation method which may yield different
structural defects. The crystalline size was determined from
full width of half maximum (FWHM) of the most intense
peak obtained by shown scanning of X-ray diffraction
pattern. The grain size was calculated by using Scherrer’s
formula: d = 0.9λ/ βcosθ
The crystalline size can be calculated by using Scherrer
equation21,22. Where, d is the crystalline size, λ is the X-ray
wavelength of the Cu Kα source (λ=1.54056 A0), β is the
FWHM of the most predominant peak at 100 % intensity, θ
is the Braggs angle at which peak is recorded. In order to
obtain pure nanocrystalline ZnFe2O4 particles and understand
the thermal characterizations, the as prepared ZnFe2O4
powder is further calcined at 180, 300, 500, 800 and 1000 0C
respectively (the calcined temperature assigned as TC).
Figure-2 present XRD patterns for ZnFe2O4 oxide
nanoparticles. The effects of the calcinations temperature on
the crystallite size of ZnFe2O4 particles can be demonstrated.
Traces of ZnFe2O4 crystallites phases (111), (311), (400),
(422) and (511) are detected in the XRD pattern for all
calcined temperatures and then their intensities increase
abruptly when the TC above 10000C. In general, the
sharpness of the XRD peak (i.e. high crystallinity) is
increased as the TC increases.
According to the (311) diffraction pattern of ZnFe2O4
crystalline, the particle size of ZnFe2O4 can be calculated
from the full width at haif-maximum using the Scherrer
equation. Obviously, the particle size of ZnFe2O4 changes as
the Tc controlled fewer than 180, 300, 500, 800 and 10000C,
the order is 22, 22, 25, 32 and 32 nm, respectively. These
indicate that the crystallinity of ZnFe 2O4 is accelerated as the
Tc above 5000C. Illustrates the relationship between the
annealing temperature and the average crystal size of the
ZnFe2O4 nanoparticles. It is obvious that the ZnFe2O4
nanoparticle grows slowly at 300-5000C and 800-10000C,
respectively, the nanoparticle grow rapidly at 800 0C.
Particle size Analyzer: Particle size distribution studies
Figure-3 have been carried out by using dynamic light
scattering techniques (DLS) via laser input energy of 632
nm).
It was observed that zinc cobalt oxide nanoparticles particles
have narrow size distribute within the range of about 30-40
nm. Which well matches are with calculated from DebyeScherrer equation.

Figure-1
DTA-TG the prepared ZnFe2O4 nominal composition

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Research Journal of Recent Sciences _____________________________________________________________ ISSN 2277-2502
Vol. 1 (ISC-2011), 202-206 (2012)
Res.J.Recent Sci.

O

1000 C

511

422

400

220

111

Intensity

311

222

Energy dispersive X-ray microanalysis analysis (EDX),
Figure-4 shows the energy dispersive X-ray spectrum of
ZnFe2O4. This was carried out to understand the composition
of zinc, iron and oxygen in the material. There was no
unidentified peak observed in EDX. This confirms the purity
and the composition of the ZnFe2O4 nanomaterial

O

800 C
O

500 C
O

300 C
O

180 C

20

40

60

80

100

2

Figure-2
XRD patterns for ZnFe2O4 oxide nanoparticales
180, 300, 500, 800 and 10000C
1.2

PL Intensity

1
0.8
0.6
0.4
0.2

35
.4

28
.6
7

23
.2
3

18
.8
1

15
.2
4

12
.3
5

10

6

2

0

Wave le ngth in nm

Figure-3
Particle Size Distribution of ZnFe2O4 oxide Nanoparticale
Scanning
electron
micrograph
analysis:
The
microstructure of the sintered samples can be visualized from
scanning electron microscope (SEM) tool. Figure- 4 shown
the particle morphology of high resolution, the particle are
most irregular in shape with a Nanosize range. Some
particles are found as agglomerations containing very fine
particles the particles shapes are not defined porous nature
and small and large core, spongy pores are seen in the
micrograph.

a

Figure-5
EDX pattern of ZnFe2O4
Transmission electron microscopy analysis (TEM), The
TEM image of the mixed precursor calcined at 800 0C for 2h
are shown in figure- 6. It indicates the presence of ZnFe2O4
nanoparticles with size 30-40 nm which form beed type of
oriental aggregation throughout the region. The HRTM
image figure- 6 (b) shows well developed lattice fringes,
which are correlated well with the XRD result. The selected
area electron diffraction (SAED) pattern figure- 6 (a) shows
the spot type pattern which is indicative of the presence of
single crystalline particles. No evidence was found for more
than one pattern, suggesting the single phage nature of the
material.

a

21nm

b

b

100nm

Figure-4
SEM images of the self combustion product the powder
annealed at 8000C at (a) and (b) high resolution
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Figure-6
TEM image of the combustion product after annealing at
8000C for .and HRTEM image of the same (b) with the
inset showing the SAED pattern on the spot in (a)
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Research Journal of Recent Sciences _____________________________________________________________ ISSN 2277-2502
Vol. 1 (ISC-2011), 202-206 (2012)
Res.J.Recent Sci.
Density measurement: Density evaluation from X-ray data,
The X-ray density of the samples has been computed from
the values of lattice parameters using the formula 23-24. d =
8M/Na3, Where 8 represent the number of molecules in a
unit cell of a spinel lattice, M the molecular weight of the
sample, N the Avogadro’s number, and a the lattice
parameter of the sample. The lattice constant for the cubic
was calculated using the equation d = a/ (h2+k2+l2)1/2.
Tap density: The as prepared ZnFe2O4 was crushed in an
agate mortar using a pestle and a mortar. A known amount of
this powder was filled into a graduated cylinder of 10 ml
capacity. The cylinder was ta,ed until the powder level
remained unchanged. The volume occupied by the powder
was noted. The ratio between the weight of the substance and
the volume gave tap density25.
Powder density: The powder densities were measured using
Archimedes principal 26 with a picometer and xylene as a
liquid medium. The pynometer of volume 10 ml was used.
The following weight were taken and used in the density
calculation.
Weight of the bottle +
W1g, Weight of the bottle +
substance = W2g,
Weight of the bottle + substance + xylene =W3g,
Weight of the bottle + xylene + W4g,
Density of xylene = ρsol. ρ=(W2-W1) ρsol/(W4-W3) + (W2-W1)

Sample
ZnFeO4

Table-1
Densities of ZnFe2O4 in kg/m3
Density from
Tap
XRD
density
6170.22

6188.12

Bulk
density
6138.888

Superhydrophilic Test : Wettability shows the behavior of
water droplet on u,er surface of material depends on surface
energy and surface roughness of material. Thomas Young
had described the force acting on a liquid droplet spreading
on surface. The so-called contact angle (θ) is related to
interfacial energies acting between the solid-liquid ( SL),
solid-vapor (SV) and liquid-vapor (LV) given by relation.

cos  

( SV   SL )

 LV

(1)

The expression given by Equation 1 is strictly valid only for
surfaces that are atomically smooth, chemically
homogeneous, and those that do not change their
characteristics due to interactions of the probing liquid with
the substratum, or any other outside force. Wenzel regime,
the liquid wets the surface, but the measured contact angle
(θ*) differs from the “true” contact angle (θ) by Wenzel’s
equation for rough surface r > 1 27.-30.

cos *  r cos

(2)

Where r is the roughness factor of the surface. The
wettability nature of our synthesized material is super
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hydrophilic in the Wenzel because of highly rough surface
nature clearly seen from SEM images with consideration
given to the surface roughness.Figure-5 (a-b) shows the
image of contact angle on rough surface of zinc iron oxide
material. It seen that contact angle of material is θ =0, hence
material in superhydrophilic ((θ ≤ 5) may be due to high
energy surface and porous nature.
In to characterization: Wetting experiment of synthesized
pure zinc iron oxide evaluated by contact angle measurement
were performed by the sessile drop method using an
Advanced goniometer (Model110, Ram hart Instrument Co.,
USA) a,aratus and distilled water droplets (0.01ml) were
delivered to surface of zinc iron oxide material at different
points.

a

b

Figure-7 (a-b)
Photograph of measured contact angle on rough surface
of zinc iron oxide materials.

Conclusion
Nanocrystalline ZnFe2O4 has been synthesized by self
combustion route. This synthesis route may be used for the
synthesis of other metal oxide, characterization by using
SEM micrographs show a porous structure and submicron
grains 100 nm, by XRD technique the average crystal size of
the ZnFe2O4 nanoparticles ranges from about 22, 22, 25, 32
and 32 nm. under 180-10000C. Elemental analysis confirmed
by using EDX. Density can be carried out by different
technique it was found to a,roximately same. Wetability of
this material obtained from contact angle goniometer. The
contact angle (θ) is zero, which indicates that oxide material
was superhydrophilic.

Acknowledgment
The S.V.Bangale are grateful to the Principal, Dr. Patangrao
Kadam Mahavidyalaya, Sangli India for providing laboratory
facilities and authors thankful for to Mr. Satish A. Mahadik
for help in hydrophilic studies.

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