Sensors
and
Actuators
B
177 (2013) 397–
403
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Sensors
and
Actuators
B:
Chemical
journa
l
h
o
mepage:
www.elsevier.com/locate/snb
The
effects
of
sintering
temperature
of
MnCr
2
O
4
nanocomposite
on
the
NO
2
sensing
property
for
YSZ-based
potentiometric
sensor
Quan
Diao
a
,
Chengguo
Yin
a
,
Yingzhou
Guan
a
,
Xishuang
Liang
a,∗
,
Shuo
Wang
a
,
Yingwei
Liu
a
,
Yunfeng
Hu
b
,
Hong
Chen
b
,
Geyu
Lu
a,∗∗
a
State
Key
Laboratory
on
Integrated
Optoelectronics,
College
of
Electronic
Science
and
Engineering,
Jilin
University,
2699
Qianjin
Street,
Changchun
130012,
China
b
Department
of
Control
Science
and
Technology,
Jilin
University,
2699
Qianjin
Street,
Changchun
130012,
China
a
r
t
i
c
l
e
i
n
f
o
Article
history:
Received
16
June
2012
Received
in
revised
form
10
November
2012
Accepted
14
November
2012
Available online xxx
Keywords:
NO
2
sensor
YSZ
MnCr
2
O
4
Mixed
potential
a
b
s
t
r
a
c
t
In
this
paper,
MnCr
2
O
4
with
spinel
structure
has
been
prepared
by
using
polymeric
precursor
method.
The
thermal
stability,
grain
size
and
surface
morphology
of
MnCr
2
O
4
calcined
at
different
temperatures
were
studied
using
thermogravimetric
analysis
and
differential
scanning
calorimeter
analysis
(TG-DSC),
X-ray
diffraction
(XRD),
scanning
electron
microscopy
(SEM).
Then
the
YSZ-based
sensors
using
MnCr
2
O
4
sin-
tered
at
different
temperatures
(800,
900,
1000,
1100
and
1250
◦
C)
as
electrode
were
fabricated
and
their
NO
2
sensing
properties
were
investigated.
Results
demonstrate
that
MnCr
2
O
4
sample
calcined
at
1000
◦
C
exhibits
higher
response
to
100
ppm
NO
2
,
which
is
about
73
mV.
It
is
believed
that
the
calcined
temper-
ature
affect
the
material’s
sensing
properties.
In
addition,
the
sensing
characteristics
such
as
selectivity,
repeatability
were
investigated.
© 2012 Elsevier B.V. All rights reserved.
1.
Introduction
Lots
of
nitrogen
oxide
(NO,
NO
2
and
N
2
O)
from
fossil
fuel
com-
bustion
have
been
a
major
pollutant,
which
caused
environmental
problems
such
as
photochemical
smog,
acid
rain,
ozone
deple-
tion
and
greenhouse
effects.
To
detect
the
NO
x
in
environment,
the
high
performance
NO
x
sensor
has
been
urgently
desired.
The
NO
x
sensors
using
yttria-stabilized
zirconia
(YSZ)
as
oxygen-ion-
conducting
electrolyte
have
been
widely
reported
[1–7].
YSZ-based
potentiometric
sensors
are
operated
by
measure-
ment
of
the
open-circuit
potential
(OCP)
between
two
dissimilar
electrodes,
generally,
in
which
Pt
as
reference
and
metal
oxide
as
sensing
electrodes.
The
different
reaction
kinetics
on
the
two
electrodes
result
in
a
measurable
potential
difference
which
is
cor-
related
to
the
gas
composition
as
well
as
concentration
[8].
Many
studies
focused
on
sensing
electrode
materials,
device
structure
and
sensing
mechanism
[9–28].
Lots
of
metal
oxide
and
mixed-
oxide
have
been
investigated
in
YSZ-based
potentiometric
sensors
in
some
early
researches.
N.
Miura
et
al.
reported
that
ZnCr
2
O
4
,
ZnFe
2
O
4
,
NiO
and
Cr
2
O
3
+
NiO
could
give
good
sensing
proper-
ties
to
NO
2
at
elevated
temperature
[29–36].
P.
Dutta
et
al.
also
examined
that
Cr
2
O
3
was
an
excellent
sensing
electrode
[37].
E.
∗
Corresponding
author.
Tel.:
+86
431
85168384;
fax:
+86
431
85167808.
∗∗
Corresponding
author.
Tel.:
+86
431
85167808;
fax:
+86
431
85167808.
E-mail
addresses:
liangxs@jlu.edu.cn (X.
Liang),
lugy@jlu.edu.cn
(G.
Lu).
Bartolomeo
et
al.
reported
that
WO
3
,
LaFeO
3
and
La
0.8
Sr
0.2
FeO
3
showed
good
sensing
performance
[38].
Girish
M.
Kale
et
al.
devel-
oped
CuO
+
CuCr
2
O
4
sensing
electrode
[39].
Also,
the
morphology
of
sensing
electrode
(SE)
and
sintering
temperature
of
SE
were
found
to
be
main
factors
of
the
NO
2
sensitivity
[36,40–42].
In
this
work,
we
synthesized
Mn/Cr
mixed-oxides
for
YSZ-based
potentiometric
sensors,
which
were
tested
about
NO
2
sensing
property.
The
effects
of
annealing
temperature
on
the
particle
size
and
NO
2
-sensing
property
of
MnCr
2
O
4
nanocomposite
were
inves-
tigated.
2.
Experimental
2.1.
Materials
preparation
MnCr
2
O
4
was
prepared
from
their
nitrates
by
the
poly-
mer
precursor
method.
In
a
typical
synthesis
process,
cit-
ric
acid
and
stoichiometric
amounts
of
manganous
acetate
hydrate
(Mn(CH
3
COO)
2
·4H
2
O)
and
chromium
(III)
nitrate
hydrate
(Cr(NO
3
)
3
·9H
2
O)
were
dissolved
in
deionic
water,
in
which
the
molar
ratio
between
citric
acid
and
all
the
metal
cations
(Mn
and
Cr)
was
3:1
with
stirring
at
70
◦
C
for
2
h.
Then
ethylene
glycol
was
added
to
the
above
solution
with
the
citric
acid/ethylene
glycol
mass
proportion
of
6:4.
The
resulted
solution
was
maintained
at
70
◦
C
for
4
h
at
tube
furnace,
and
sintered
at
800,
900,
1000,
1100
and
1250
◦
C
for
2
h
in
Muffle
furnace
after
being
grinded
simply.
0925-4005/$
–
see
front
matter ©
2012 Elsevier B.V. All rights reserved.
http://dx.doi.org/10.1016/j.snb.2012.11.040