Thermal expansion, microhardness and oxygen permeation of La1-xSrxCo0.8Fe0.2O3+δ membranes

Article abstract of DOI:10.14233/ajchem.2017.20681

Dense ceramic membranes acting as oxygen and electron ion-conductors can be used as the catalysts for syngas production. The La_1-xSr_xCo_0.8Fe_0.2O_3+δ (LSCF) systems were known to have a high ionic and electronic conductivity. In the application, the La_1-xSr_xCo_0.8Fe_0.2O_3+δ membranes required low thermal expansion, microhardness and high oxygen permeation flux. The changes in the expansion, hardness, and oxygen flux of the La_1-xSr_xCo_0.8Fe_0.2O_3+δ perovskite membranes with various strontium substitutions were studied. The magnitude of both the thermal expansion and the oxygen content of the La_1-xSr_xCo_0.8Fe_0.2O_3+δ membranes decreased with up to 20 % strontium substitution and then increased with 30 and 40 % strontium ion substitution. Meanwhile, the hardness and shrinkage improved by various strontium ion substitutions, except with 20 % strontium. The highest oxygen flux over La_1-xSr_xCo_0.8Fe_0.2O_3+δ (0.0 ≤ x ≤ 0.4) membranes in the surface exchange-controlled processes was found of the membrane with 30 % strontium substitution.

Full text of DOI:10.14233/ajchem.2017.20681

Asian Journal of Chemistry; Vol. 29, No. 10 (2017), 2191-2196
ASIAN JOURNAL OF CHEMISTRY
https://doi.org/10.14233/ajchem.2017.20681
Thermal Expansion, Microhardness and Oxygen Permeation of La1-xSr Co0.8Fe0.2O3+δ Membranes
x
1,2
1
1
1,*
1,*
A. ALIYATULMUNA , W.P. UTOMO , R.Y.P. BURHAN , H. FANSURI and I.K. MURWANI
1
2
Department of Chemistry, Institut Teknologi Sepuluh Nopember (ITS), Kampus ITS Sukolilo, Surabaya 60111, Indonesia
Department of Chemistry, Universitas Negeri Malang (UM), Jalan Semarang 5, Malang 65145, Indonesia
*
Corresponding authors: Tel.: +62 31 5935208; E-mail: h.fansuri@chem.its.ac.id; irmina@chem.its.ac.id
Received: 31 March 2017; Accepted: 15 June 2017; Published online: 31 August 2017;
AJC-18517
Dense ceramic membranes acting as oxygen and electron ion-conductors can be used as the catalysts for syngas production. The
3+δ (LSCF) systems were known to have a high ionic and electronic conductivity. In the application, the
3+δ membranes required low thermal expansion, microhardness and high oxygen permeation flux. The changes in the
expansion, hardness, and oxygen flux of the La1-xSr 3+δ perovskite membranes with various strontium substitutions were studied.
The magnitude of both the thermal expansion and the oxygen content of the La1-xSr 3+δ membranes decreased with up to 20 %
strontium substitution and then increased with 30 and 40 % strontium ion substitution. Meanwhile, the hardness and shrinkage improved
by various strontium ion substitutions, except with 20 % strontium. The highest oxygen flux over La1-xSr 3+δ (0.0 ≤ x ≤ 0.4)
La1-xSr
La1-xSr
x
Co0.8Fe0.2
Co0.8Fe0.2
O
O
x
x
Co0.8Fe0.2O
x
Co0.8Fe0.2O
x
Co0.8Fe0.2O
membranes in the surface exchange-controlled processes was found of the membrane with 30 % strontium substitution.
Keywords: Oxygen flux, Oxygen Non-stoichiometry, Shrinkage.
of ions in LSCF’s B site, the cobalt ion enhances the transport
INTRODUCTION
property of oxygen ion. However, it also decreases the thermal
stability in reduction atmosphere. Meanwhile, iron ion increases
the thermal stability and has the highest ionic conductive
property as well as electronic conductive after cobalt [1].
Perovskite type oxides based on LaCoO is an interesting
3
topic, since it has the capability to conduct oxygen anions
through a difference in oxygen activity between high and the
low partial pressure side [1]. Material of oxygen ion conductor
is used as oxygen pump in fuel cell system and also as memb-
rane catalysts in partial oxidation reaction which produce
synthesis gas and methanol [2].
There are many studies on La1-xSr Co0.8Fe0.2O3+δ composi-
x
tion with a high content of both strontium and cobalt [7]. How-
ever, there is still limited information on thermal expansion
and oxygen transport characteristics of LSCF membranes with
low Sr and high Co contents. Hence, this research aimed to
characterize the hardness, thermal expansion and oxygen flux
To increase the transport of oxygen ion, it is necessary to
substitute A and B site cations of LaCoO
such as substitution in La1-xSr
decades ago, Teraoka was the first researcher who observed
3+δ material. Hence forth, there is research
3
perovskite oxide,
x
Co0.8Fe0.2O3+δ (LSCF). Three
of La1xSr Co0.8Fe0.2O3+δ with 0 until 40 % Sr substitution effect
x
for lanthanum with 10 % intervals (x = 0.0-0.4). The thermal
expansion coefficient of material in the air has a similar
tendency with such material thermal expansion coefficient in
reducing atmosphere at various temperatures [8]. The crystal
structure and thermal stability were also observed to support
La1-xSr Co0.8Fe0.2O
x
on the properties of oxygen ion transport and its influence on
the oxygen separation from the air in LSCF materials [3].
La1-xSr Co0.8Fe0.2O3+δ dense membranes as the catalyst in
x
industrial processes require low thermal expansion value,
thermal stability and high oxygen permeation. The difference
in thermal expansion coefficient between the air side of the
membrane and the oxygen-lean side of the membrane results
in the cracking of membrane in high-temperature quartz reactor
transport property of oxygen ion of La1-xSr
.0-0.4).
x
Co0.8Fe0.2O3+δ (x =
0
EXPERIMENTAL
Powder synthesis: The perovskite materials of LSCF
[
4]. The thermal expansion coefficient in the LSCF reduced
along with the decreasing strontium ion substitution [5].
However, the low Sr substitution in LSCF caused the reduction
of ionic conductivity [6]. The researchers observe the content
(x = 0.0-0.4) series were synthesized by solid state reac-
tion method from oxide precursors. The chemicals used
in the preparation were La
2
O
3
(Merck, 99.5 %), Co
3
O
4

1
-x
x
0.8
0.2 3+δ
2
192 Aliyatulmuna et al.
Asian J. Chem.
(
Aldrich, 99.5%), Fe
2
O
3
(Merck, 97 %) and Sr(NO
3
) (Merck,
2
RESULTS AND DISCUSSION
9
9.0 %).
The precursors with particular stoichiometric comparisons
Weight loss of La1-xSr
x
Co0.8Fe0.2
O
3±δ through TGA curve
The weight changes of La1-xSr
x
Co0.8Fe0.2
O
3±δ (x = 0.0-0.4)
were mixed and put into ball mills with an amount of methanol
for 24 h to be then drained at 60 °C. After drained, the pre-
cursors were then calcined in the furnace at 1000 °C for 2 h.
The calcination process was repeated one more time to refine
the formation of perovskite.
Characterizations: The thermal characteristics of perov-
skite oxide powder were characterized by using TGA/DSC.
The utilized TGA/DSC method was adopted from Wang et al.
samples during the heat process from 200 °C until 1100 °C
were analyzed through the TGA curve in the hydrogen atmos-
phere (Fig. 1). The weight change curves of the x = 0.1 sample
and x = 0.2 sample and the x = 0.3 sample and x = 0.4 sample
tend to be almost similar. There are no weight loss on the x =
0
5
.1 sample and x = 0.2 sample at the temperature range of
60-640 °C. Whereas, there are weight loss caused by the
SrCO
The weight losses of the La1-xSr
samples are usable in the determination of contents of both
oxygen anions and B site cations of La1xSr
regard to a following decomposition reaction [11]:
3
decomposition on x = 0.3 sample and x = 0.4 sample.
[
9]. The method was initiated with the sintering process on
x
Co0.8Fe0.2O3+δ (x = 0-0.4)
the powder material from room temperature up to 950 °C with
the increasing temperature rate of 100 °C/min. The materials
were left at the temperature of 950 °C for 60 min. Subsequently,
the temperature was cooled down from 950 °C to room tempe-
rature. Then, the materials were left at the room temperature
for 10 min. Next, the powder materials were sintered one more
time up to the temperature of 1100 °C with 10 °C/min sintering
x
Co0.8Fe0.2O3+δ with
5% H
2
La1-xSr
x
Co0.8Fe0.2
O3+δ → (1–x)/2La
2
O + xSrO +
3
0.8Co + 0.2 Fe + ((3 + δ) – (1 – x).1.5 – x).0.5O
2
rate in the flow of 5 %H /Ar and with the flow rate of 20 mL/min.
2
1
00
x = 0.1
The materials were left for 180 min after reaching 1100 °C.
Subsequently, the phase compositions of the synthesized
perovskite oxides were then determined via X-ray diffraction.
The diffraction characterization was performed at a 2θ starting
from 30° until 60° with the interval of 0.02° and the speed of
98
9
6
4
x = 0
9
x = 0.2
-1
92
90
6
° min . The utilized X-ray is Kα1 radiation sourced from Cu
with the wavelength (λ) of 1.54056 Å.
x = 0.4
The synthesized perovskite oxides of LSCF were then
pressed to be disks and sintered at 1100 °C for 8 h. The charac-
terization of hardness of disk shaped membranes was per-
formed in HM-200-Mitutoyo series of an MicroVickers Hardness.
The load given to the material was 1 N with the indentation
period of 30 min. The characterization of membrane hardness
was conducted in 7 membrane points.
x = 0.3
8
8
8
8
6
4
82
80
78
The scanning electron microscopy (SEM) was conducted
to observe the surface morphology of the membranes using
ZEISS EVO MA 10. The thermal expansion coefficient (TEC)
was characterized using Thermal Mechanical Analyzer (TMA)
1
00 200 300 400 500 600 700 800 900 1000 1100
Temperature (°C)
Fig. 1. Temperature dependence of the weight loss of La1-xSr
membranes in 5 % H
x
Co0.8Fe0.2
O
3+δ
2
(
Mettler Toledo, Switzerland). The Thermal Mechanical
Analyzer was used at the temperature of 200 up to 1100 °C on
the temperature increasing rate of 20 °C/min.
Table-1 shows that the samples with the higher contents
of oxygen result in the larger weight losses. The x = 0. 4 sample
3+
4+
The oxygen flux measurements utilized silver paste as
the adhesive between the membrane sample and the quartz
tube. They were carried out at 550 to 950 °C with the tempe-
rature increasing rate of 100 °C min. The oxygen acted as the
feed gas on the flow rate of 150 mL/min. High purity helium
was flown on the other side of the membrane on the flow rate
of 30 mL/min. The flow rate was controlled by mass flow
controller (MFC).. The gas chromatography complemented
with 13X molecular sieve column was then connected (inline)
on the gas exit. Subsequently, the oxygen flux was measured
with eqn. 1:
contains more Co and Fe than the x = 0.3 sample.
2+
Besides substitution of Sr that is higher, the x = 0.4 sample
contains more oxygen anions than the x = 0.3 sample. The
3+
4+
high oxidation state (Co and Fe ) of x = 0.4 sample be impor-
tant in order to maintain the electroneutrality of the sample.
2
+
Meanwhile, the x = 0.3 and x = 0.4 samples have higher Co
3
+
and Fe content than x = 0.1 and x = 0.2 samples. The forma-
tions of SrCO on x = 0.3 and x = 0.4 samples are balanced by
3
a number of B site cations of La Sr Co Fe O with low
1
-x
x
0.8
0.2 3+δ
2+
3+
oxidation state (Co and Fe ).
Crystal structure of La Sr Co Fe O : The crystal
phases of the powder material of La1-xSr
0.4) were identified by using XRD (Fig. 2). All samples have
perovskite phase with the SrCO phase (PDF No. 71-2393)
identified in sample with 30 % and 40 % Sr substitution (x =
0.3 and x = 0.4) for La. The formations of strontium carbonate
x
Co0.8Fe0.2O3+d (x = 0-

 21 
 79 
 F
%N ·
JO2 = %O −

2


2

(1)
 A

3
-1
-2
where J
O
was the oxygen flux (mL min cm ), F was the
sweep gas flow rate (mL min ) and A was the membrane area
cm ). A = 0.44 cm [10].
2
-1
2
2
(
result from some Sr which get out of the La1-xSr
x
Co0.8Fe0.2
O
3+δ

Vol. 29, No. 10 (2017)
Thermal Expansion, Microhardness and Oxygen Permeation of La1-xSr Co0.8Fe0.2O3+δ Membranes 2193
x
TABLE-1
WEIGHT LOSSES OF VARIOUS Sr SUBSTITUTIONS IN 5 % H2
Cation contents at B site over La Sr Co Fe O
δ
(%)
4+
1
-x
x
0.8
0.2 3+
3+
La Sr Co Fe O ±δ
Weight loss of
samples (%)
Oxygen content
1-x
x
0.8
0.2
3
2+
3+
Co /Co
Fe /Fe
samples
(3 + δ)
2
+
3+
3+
4+
Co
Co
Fe
Fe
x = 0.0
x = 0.1
x = 0.2
x = 0.3
x = 0.4
8.52
8.51
8.36
8.73
12.07
3.06
2.68
2.63
3.07
3.15
N/A
45.3
50.0
95.2
90.9
N/A
54.7
50.0
4.8
100
53.4
39.7
97.3
85.4
0
46.6
60.3
2.7
9.1
14.5
whenx=0.0[15].ThechemicalexpansionsofLa1-xSr
x
Co0.8Fe0.2
O
3+δ
*
SrCO3
increased sharply with Sr substitution increasing to x = 0.2.
However slight increasing of chemical expansions is observed
for the sample of x = 0.3 until x = 0.4 (Fig. 3). It is possible
since the maximum Sr which could substitute La on
x = 0.4
x = 0.3
x = 0.2
La1-xSr Co0.8Fe0.2O3±δ lattice is less than 30 % (x < 0.3).
x
0
.65
.60
0
x = 0.1
x = 0
0.55
0.50
0.45
0.40
0.35
0.30
LaCoO No. 84-0847
3
30
32 34 36 38 40 42 44 46 48 50 52 54 56 58 60
(°)
Fig. 2. XRD pattern of La1-xSr
2θ
0.25
0.20
x
Co0.8Fe0.2O3+δ samples
0
.15
.10
lattice and reacted with the CO and CO
3+δ samples possess a rhombohedral struc-
ture, similar to structure of the LaCoO parent (PDF No. 84-
847). Both edge length (a) and volume of unit cell increase
2
in the air [12]. All
0
La1-xSr Co0.8Fe0.2O
x
0
.10
0.15
0.20
0.25
x
0.30
0.35
0.40
3
Fig. 3. Influences of Sr substitution on chemical expansion
0
with increasing of Sr substitution (Table-2). The rhombohedral
structure approaches cubic structure when unit cell angle of x
The x = 0.4 sample has higher lattice parameters and larger
chemical expansion than the x = 0.3 sample, even though the
differences are slight. It is because the x = 0.4 sample contains
=
0.4 is smallest and its peak (2θ ≈ 32.8-33.2) is sharp single
(
2θ ≈ 32.8-33.2) [13].
3+
3+
higher oxidation anions, Co and Fe compared with the x =
.3 sample (Table-1).
Besides larger radius of Sr than that of La (rSr2+ = 0.158
0
TABLE-2
LATTICE PARAMETERS OF La Sr Co Fe O
δ
0.2 3+
2+
3+
1-x
x
0.8
nm and rLa3+ = 0.150 nm), the distance between ions in
Unit cell 3
a
Sample
x
a (nm)
α (°)
volume (nm )
0.1118
La Sr Co Fe O also contributes towards the increase of
1
-x
x
0.8
0.2 3+δ
LaCo Fe O
3
0.0
0.1
0.2
0.3
0.4
0.5379
0.5386
0.5401
0.5408
0.5412
60.72
60.66
60.54
60.48
60.45
the lattice parameters and chemical expansion. The excess
oxygen ions of x = 0.4 sample increase the repulsion between
oxygen anions so that the distance between the oxygen anions
in the lattice of x = 0.4 sample increase and the cations radius
on A site became larger [16]. Additionally, the repulsion
0
.8
0.2
La Sr Co Fe O
3
0.1121
0.1128
0.1131
0.1133
0
.9 0.1
0.8
0.2
La Sr Co Fe O
0
.8 0.2
0.8
0.2
La Sr Co Fe O
3
0
.7 0.3
0.8
0.2
La Sr Co Fe O
3
0
.6 0.4
0.8
0.2
a
Unit cell volumes were calculated by the equation:
3+
between La and cations in B site with high oxidation state,
3
2
3
V = a 1−3(cos ∝) +2(cos∝) [[ RR ee ff .. 11 22 ]]
3+
4+
3+
3+
4+
i.e. Co and Fe , also increase the La -(Co , Fe ) distance
on x = 0.4 sample.
Discussion about the chemical expansion [14] of samples
with respect to data from both TGA and XRD is as follows:
The chemical expansion is defined with the eqn. 2:
Thermal expansion coefficient (TEC): The thermal
expansion coefficient of all La Sr Co Fe O membranes
1
-x
x
0.8
0.2 3+δ
started to increase at the temperature of 200 °C up to 850 °C
and then reduced up to 1100 °C (Fig. 4). The increase of thermal
expansion coefficient by temperature was caused by the forma-
tion of larger particles [17]. The densification and formation
of particles started at the temperature of 850 °C and leads to
the contraction of La Sr Co Fe O lattice [18].
(
a −a )
x 0
ε =
(
2)
a0
is unit cell edge of La1-xSr
tution from 10 up to 40 % (x = 0.1-0.4) and a
where a
x
x
Co0.8Fe0.2
O
0
3+δ for Sr substi-
is unit cell edge
1
-x
x
0.8
0.2 3+δ

2
194 Aliyatulmuna et al.
Asian J. Chem.
2
2
2
2
2
2
2
2
1
1
1
1
1
1
7
6
5
4
3
2
1
0
9
8
7
6
5
4
24
3.2
2
3
2
3
.1
.0
2
21
3
2
0
9
x = 0
1
2.9
x = 0.1
18
2.8
17
16
15
14
x = 0.4
x = 0.3
2.7
2.6
x = 0.2
2
00 300 400 500 600 700 800 900 1000 1100
Temperature (°C)
Fig. 4. Temperature probes of the thermal expansion coefficient in air for
3+δ samples
0.0
0.1
0.2
x
0.3
0.4
Fig. 5. Correlation between the thermal expansion coefficient,the oxygen
content and the Sr substitution for La1-xSr 3+δ samples
x
Co0.8Fe0.2O
La1xSr Co0.8Fe0.2O
x
microstructure without obvious pores (Fig. 6). The Sr metal
has the lowest melting point among other elements that compose
The average TEC and the oxygen content in
3+δ have a similar curve (Fig. 5). The x = 0.2
sample has both the smallest oxygen stoichiometry and the
highest Fe content (Table 1). The oxygen losses lead the
decrease in the coordination number of A site metal ions so
La1-xSr Co0.8Fe0.2O
x
the La1-xSr
x
Co0.8Fe0.2
O
3+δ compound [20]. It allows the particles
in the compoundto weld easily and then formed a large particle
17]. Besides the high densification, the x = 0.4 membrane also
4+
[
has the largest shrinkage percentage and hardness (Fig. 7).
Different with the x = 0.4 membrane, the membranes without
strontium do not experience densification but coarsening so
that not only the grains but also pore sizes of the x = 0.0 membrane
are large. Meanwhile, the low densification of x = 0.0 membrane
is conforming to the low percentage of shrinkage and hardness of
x = 0.0 membrane. Such findings support the research conducted
by Tan et al. [21] on Ba0.8Sr0.2Co0.8Fe0.2O3-δ membrane [21].
The shrinkage increases with the formation of void spaces
within the lattice structure as a result of the ion substitution
that the radii of A site metal ions in La1-xSr
x
Co0.8Fe0.2O3±δ are
also decreased [16]. The small radius of metal ion in A site
4+
2-
and the shortened Fe -O distance result in the declined TEC.
In the contrary, excess oxygen in x = 0.3 and x = 0.4 samples
increase the TEC.
3+
For the sample, x = 0.1, the highest content of La results
in a high level of TEC. This is due to the longer distance of
3+
2+
La -B-site ion than that of Sr -B-site ion [19].
Surface morphology of membrane: The membranes with
the largest Sr content, namely 40 % (x = 0.4) showed dense
x
Fig. 6. SEM images of La1-xSr Co0.8Fe0.2
O
3+δ

Vol. 29, No. 10 (2017)
Thermal Expansion, Microhardness and Oxygen Permeation of La1-xSr Co0.8Fe0.2O3+δ Membranes 2195
x
9
00
50
00
50
00
50
00
50
00
450
00
50
The x = 0.1 membrane has less grain boundaries (large-
sized grains) compared with the x = 0.4 membrane but the x =
15
8
0.1 membrane results in higher oxygen flux. It is made possible
8
14
since the x = 0.1 sample has a higher lattice free volume than
the x = 0.4 sample. The highest until the lowest lattice free
volumes are respectively found in the samples of x = 0.1 (12
7
13
7
12
6
3
3
3
nm ), 0.3 (11.8 nm ) and 0.4 (11.5 nm ). The reduction of lattice
free volume on the x = 0.3 and x = 0.4 samples result from the
samples which contain excess oxygen. According to Tan et al.
6
11
5
10
[
24], the increasing lattice free volume improves the oxygen
5
ion transfer. The grain boundary area and then the lattice free
9
8
volume mostly influence the oxygen flux in La1-xSr Co0.8Fe0.2O
x 3+δ
4
membrane.
3
0.0
0.1
0.2
x
0.3
0.4
Conclusion
Fig. 7. Correlation between shrinkage, microhardness and Sr substitution
for La1-xSr 3+δ membranes
The dense ceramic membranes of La1-xSr Co0.8Fe0.2O
x
3+δ
x
Co0.8Fe0.2
O
(0.0 ≤ x ≤ 0.4) had been successfully produced from the
3+δ powders which were synthesized through
La1-xSr Co0.8Fe0.2O
x
2
+
the means of solid state reaction method. Such membranes
were characterized by using XRD, thermal gravimetric analysis,
hardness, thermal expansion and oxygen flux measurement.
The strontium carbonate was formed by the substitutions of
with a larger radius, namely Sr , to the ion with a smaller
radius i.e. La [22].
3+
Oxygen permeation flux:The oxygen flux measurements
were conducted successfully towards the x = 0.1, 0.3, and 0.4
membranes. Those membranes have a higher percentage of
shrinkage and hardness compared with x = 0.0 and 0.2 memb-
ranes. The low hardness causes the x = 0.0 and x = 0.2 memb-
ranes to crack when adhered to the quartz reactor for the flux
test. The highest until the lowest oxygen flux are produced by
x = 0.3; 0.1 and 0.4 membranes respectively (Fig. 8). The x =
3
0 and 40 % strontium to lanthanum, and it affected the thermal
expansion and oxygen stoichiometry. The increasing lattice
parameter of La1-xSr 3+δ with the Sr substitution is
impacted by the Sr ion radius which is higher than that of
x
+
Co0.8Fe0.2O
2
3+
the La ion. Curve of thermal expansion has a similar trend to
that of oxygen content value. In the oxygen flux measurement
from La1xSr Co0.8Fe0.2O3+δ membrane, the oxygen ion transport
x
0
.3 membrane have the highest oxygen flux since it is a
is primarily influenced by the grain boundary and then by the
free volume of lattice.
membrane with low TEC and large grain boundary area (small-
sized grains). The low TEC increases the membrane resistance
towards the stress from the gradient of the oxygen partial
pressure on both sides of the membranes during the oxygen
flux measurements. Meanwhile, the grain boundaries acted as
diffusivity paths of the oxygen. An oxygen exchange process
occurred especially on the surface of the membranes (surface
exchange-controlled processes) require small-sized grains (a
lot of grain boundaries) so that it create large oxygen flux on
the membranes [23].
ACKNOWLEDGEMENTS
This work was supported by the Doctoral Research Grants
and the STRANAS Research Grant. Thanks are also due to
the Laboratory of Energy at LPPM ITS and the Laboratory of
Materials and Energy of Chemistry Department ITS, Institut
Teknologi Sepuluh for providing the research facilities.
REFERENCES
0
.13
.12
1. A.F. Sammells and M.V. Mundschau, Nonporous Inorganic Membranes
for Chemical Processing, John Wiley & Sons, Weinheim, Chap. 6, p.
0
x = 0.3
x = 0.1
173 (2006).
2
3
4
.
.
.
P.J. Gellings and H.J. Bouwmeester, Handbook of Solid State Electro-
chemistry, CRC Press, Inc., Chap. 14 (1997).
K. Li, Ceramic Membranes for Separation and Reaction, John Wiley
0
.11
0.10
0.09
0.08
0.07
0.06
0.05
0.04
&
Sons Ltd., Chap. 6, p, 176 ( 2007).
S. Pei, M.S. Kleefisch, T.P. Kobylinski, J. Faber, C.A. Udovich, V.
Zhang-McCoy, B. Dabrowski, U. Balachandran, R.L. Mieville and R.B.
Poeppel, Catal. Lett., 30, 201 (1995);
https://doi.org/10.1007/BF00813686.
5. A.Vivet, P.M. Geffroy, T. Chartier, P. Del Gallo and N. Richet, J. Membr.
Sci., 372, 373 (2011);
x = 0.4
https://doi.org/10.1016/j.memsci.2011.02.021.
6
7
.
.
S.J. Skinner, Int. J. Inorg. Mater., 3, 113 (2001);
https://doi.org/10.1016/S1466-6049(01)00004-6.
L.-W. Tai, M.M. Nasrallah, H.U. Anderson, D.M. Sparlin and S.R.
Sehlin, Solid State Ion., 76, 259 (1995);
550
600
650
700
Temperature (°C)
750
800
850
https://doi.org/10.1016/0167-2738(94)00244-M.
E. Juste, A. Julian, G. Etchegoyen, P.M. Geffroy, T. Chartier, N. Richet
and P. Del Gallo, J. Membr. Sci., 319, 185 (2008);
https://doi.org/10.1016/j.memsci.2008.03.034.
8
.
Fig. 8. Oxygen fluxes through La1-xSr
x
Co0.8Fe0.2O3+δ membranes in function
of the temperature

2
196 Aliyatulmuna et al.
Asian J. Chem.
9
1
.
H. Wang, Y. Cong and W. Yang, J. Membr. Sci., 210, 259 (2002);
https://doi.org/10.1016/S0376-7388(02)00361-7.
17. P. Boch and J.-C. Nièpce, Ceramic Materials: Processes, Properties,
and Applications, John Wiley & Sons, Chap. 3, p. 61 (2010).
18. C. Perego and P. Villa, Catal. Today, 34, 281 (1997);
https://doi.org/10.1016/S0920-5861(96)00055-7.
19. H. Hayashi, M. Watanabe, M. Ohuchida, H. Inaba,Y. Hiei, T.Yamamoto
and M. Mori, Solid State Ion., 144, 301 (2001);
https://doi.org/10.1016/S0167-2738(01)00986-9.
20. W. Jin, S. Li, P. Huang, N. Xu, J. Shi and Y.S. Lin, J. Membr. Sci., 166,
13 (2000);
0. C. Zhang, Z. Xu, X. Chang, Z. Zhang and W. Jin, J. Membr. Sci., 299,
261 (2007);
https://doi.org/10.1016/j.memsci.2007.05.001.
1. S. Hashimoto,Y. Fukuda, M. Kuhn, K. Sato, K.Yashiro and J. Mizusaki,
Solid State Ion., 181, 1713 (2010);
1
1
https://doi.org/10.1016/j.ssi.2010.09.024.
2. N. Li, A. Boréave, J.P. Deloume and F. Gaillard, Solid State Ion., 179,
1
396 (2008);
https://doi.org/10.1016/S0376-7388(99)00245-8.
21. L. Tan, X. Gu, L.Yang, L. Zhang, C. Wang and N. Xu, Sep. Purif. Technol.,
32, 307 (2003);
https://doi.org/10.1016/S1383-5866(03)00047-9.
22. M.W. Barsoum, Fundamentals of Ceramics, IOP Publishing Ltd., Chap.
10, p. 307 (2003).
23. X. Tan, Z. Wang and K. Li, Ind. Eng. Chem. Res., 49, 2895 (2010);
https://doi.org/10.1021/ie901403u.
24. L. Tan, L.Yang, X. Gu, W. Jin, L. Zhang and N. Xu, J. Membr. Sci., 230,
21 (2004);
https://doi.org/10.1016/j.ssi.2008.01.060.
1
1
3. J.N. Kuhn and U.S. Ozkan, Catal. Lett., 121, 179 (2008);
https://doi.org/10.1007/s10562-007-9364-6.
4. Crystal Geometry Equations for XRD.
https://noppa.oulu.fi/noppa/kurssi/521104p/materiaali/521104P_k
aavoja_eri_hilatyypeille_ja_ kidejarjestelmille.
5. D. Marrocchelli, S.R. Bishop, H.L. Tuller and B. Yildiz, Adv. Funct.
Mater., 22, 1958 (2012);
1
1
https://doi.org/10.1002/adfm.201102648.
6. P. Zeng, Z. Chen, W. Zhou, H. Gu, Z. Shao and S. Liu, J. Membr. Sci.,
https://doi.org/10.1016/j.memsci.2003.10.019.
2
91, 148 (2007);
https://doi.org/10.1016/j.memsci.2007.01.003.