JP2003320607A - Oxygen permeable structure and manufacturing method therefor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an oxygen permeable structure having both of high oxygen permeability and strength, and a manufacturing method therefor. <P>SOLUTION: The oxygen permeable structure 1 comprises a porous substrate 2, the cerium oxide 3 laminated on the porous substrate 2, and the oxygen permeable thin film 4 laminated on the cerium oxide. Cerium oxide 3 is represented, for example, by a compositional formula CeO<SB>2</SB>and the film thickness thereof may be 5 nm or more. The oxygen permeable thin film 4 is, for example, an LSGF oxygen permeable thin film with a film thickness of 5 μm or less, that is, the oxygen permeable thin film represented by a compositional formula: La<SB>x</SB>Sr<SB>1-x</SB>Ga<SB>y</SB>Fe<SB>1-y</SB>O (wherein x is 0<x<1 and y is 0<y<1). Further, for example, the oxygen permeable thin film is the LSCF oxygen permeable thin film with a film thickness of 5 μm or less, that is, the oxygen permeable thin film represented by the compositional formula La<SB>x</SB>Sr<SB>1-x</SB>Co<SB>y</SB>Fe<SB>1-y</SB>O (wherein x is 0<x<1 and y is 0<y<1). <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to an oxygen permeable structure and a method for manufacturing the same.

[0002]

2. Description of the Related Art Currently, fuel cells are drawing attention as a clean energy system. The types of fuel cells include phosphoric acid type, which is being put into practical use, as well as solid polymer type,
There are molten carbonate type, solid oxide type, etc., but among them, the polymer electrolyte fuel cell (PEFC) is about 60 to 10 in particular.
Since it operates in the low temperature range of 0 ° C, electric vehicles (E
V) is expected to be applied to drive power supplies and power supplies for portable devices. In PEFC, pure hydrogen is used as a fuel and oxygen in the air is used as an oxidizer.

In this case, there is a choice of supplying pure hydrogen or reforming natural gas or the like into a fuel. Except when water can be decomposed with cheap power generation, natural gas,
Hydrogen gas is obtained by reforming hydrocarbon fuels such as methanol and gasoline. Among them, natural gas has been attracting attention because it has the least environmental load of fossil fuels. Therefore, natural gas reforming is expected as a hydrogen supply source, and development of a high-performance reformer is required. At present, the steam reforming method is most widely used in the production of hydrogen from natural gas, but in recent years, a system for producing hydrogen by a partial oxidation method using oxygen in the air directly has been drawing attention. The reaction is shown by the following equation.

[0004]

[Equation 1] FIG. 8 is a conceptual diagram for explaining a partial oxidation method using the above equation (1) as an operating principle. A pipe made of an oxygen permeable material that allows only oxygen in the air to permeate is heated to a high temperature and, for example, CH ₄ gas is introduced from one end of the pipe. Only oxygen in the air is supplied into the pipe through the side wall of the pipe,
Based on the equation (1), CH ₄ gas reacts with oxygen, is decomposed into H ₂ gas and CO gas, and is discharged from the other end of the pipe. In this case, it is necessary to supply only oxygen to the CH ₄ gas in the pipe in order to increase the hydrogen concentration. That is, if N ₂ gas in the air is present, the concentration of the obtained hydrogen gas will be reduced to ⅕. Therefore, an oxygen permeable material that extracts only oxygen from the air is required, and an oxygen ion / electron mixed conductor is currently drawing attention as the material. Oxygen permeates as an ion in the oxygen ion / electron mixed conductor, but since this mixed conductor has both the conductivity of oxygen ions and electrons, it drives the oxygen partial pressure gradient without applying an external voltage. It has the ability to permeate oxygen as a force. The performance of the reformer depends on how high the oxygen flux density can be obtained, and currently, research and development of high performance oxygen ion / electron mixed conductor materials are being actively conducted. Oxygen permeation flux density of oxygen ion / electron mixed conductor is electron conductivity,
It is theoretically expressed by the following equation, depending on the ionic conductivity, the temperature, and the film thickness of the oxygen ion / electron mixed conductor.

[0005]

[Equation 2] Where j (O ₂ ) is the oxygen permeation flux density, R is the gas constant, T is the absolute temperature, F is the Faraday constant, d is the film thickness of the oxygen ion / electron mixed conductor, and P (O ₂ ) ₁ is oxygen. Oxygen partial pressure on the supply side, P (O ₂ ) ₂ is the oxygen partial pressure on the oxygen permeation side, σ
_e is electronic conductivity, and σ _i is ionic conductivity.

As is apparent from the above equation ( ₂ ), in order to increase the oxygen permeation flux density j (O ₂ ), the electron conductivity σ
_While increasing _e and ionic conductivity σ _i , increasing temperature T, and increasing oxygen partial pressure gradient, the film thickness d of the oxygen ion / electron mixed conductor is also increased.
It can be seen that it is effective to make thin. It is considered that thinning the mixed oxygen ion / electron conductor is a very effective means for improving the oxygen permeability. Further, it is considered that the film can be made amorphous by making the film thinner, and it is expected that characteristics not observed in the bulk will be exhibited.

Incidentally, the electronic conductivity σ _e and the ionic conductivity σ _i are functions of the oxygen partial pressure gradient. FIG. 9 is a diagram showing the oxygen partial pressure gradient dependence of the electronic conductivity σ _e and the ionic conductivity σ _i . In the figure, the horizontal axis represents oxygen partial pressure on the oxygen permeation side, the left vertical axis represents conductivity, and the right vertical axis represents oxygen permeation flux density. The oxygen partial pressure on the oxygen supply side is constant at atmospheric pressure (0.21 atm). As shown in the figure, the electron conductivity σ _e exhibits a minimum value at a specific oxygen concentration gradient, and the ionic conductivity σ _i is constant regardless of the oxygen partial pressure P (O ₂ ) ₂ on the oxygen permeation side. Generally, electron conductivity and ionic conductivity are limited by the material composition and crystal structure, and the materials that can obtain high oxygen permeation flux density are limited.

Generally, oxygen transport in an oxygen ion / electron mixed conductor is rate-controlled in two processes. One is a process in which oxygen molecules in the gas phase become oxygen ions and enter the inside of a conductor, which is called a surface exchange rate-determining process. The other is the process of diffusion of oxygen ions inside the conductor, which is called the bulk diffusion rate controlling process. Although the dominant rate-determining process differs depending on the oxide, temperature, film thickness, and oxygen partial pressure, thinning is effective for improving the oxygen permeability in the case of the bulk diffusion rate-controlling described above.

[0009]

However, in the oxygen permeable structure using the conventional oxygen permeable thin film, if the film thickness of the oxygen permeable thin film is made thin, cracks are likely to occur, and it is thin due to problems of gas leakage and mechanical strength. I couldn't.

In view of the above problems, it is an object of the present invention to provide an oxygen permeable structure having both high oxygen permeable characteristics and strength and a method for producing the same.

[0011]

To solve the above problems, the present invention provides an oxygen permeable structure comprising an oxygen permeable thin film and a porous substrate, wherein cerium oxide is provided between the oxygen permeable thin film and the porous substrate. It is characterized in that it is sandwiched as a buffer layer. According to this configuration, the unavoidable chemical reaction that occurs between the porous substrate and the oxygen permeable thin film can be suppressed by sandwiching cerium oxide as the buffer layer. As a result, cracks are less likely to occur in the oxygen permeable thin film even when a thermal shock is applied, and thus an oxygen permeable structure having both high oxygen permeable characteristics and strength can be realized. Oxygen permeability thin film, the composition formula _{La x Sr 1-x Ga y} Fe 1-y O ( provided that, 0 <x <1,0 <y <1) oxygen transmission film (this material itself represented by the already published Japanese Patent Laid-Open No. 2001-2001
93325), and the porous substrate is preferably a porous alumina substrate. The oxygen permeable thin film has a composition formula of La _x Sr _1-x Co _y Fe _1-y O (where 0 <x <
Oxygen-permeable thin film represented by 1,0 <y <1 (this substance itself has already been published. Chem. Lett., (1
985) 1743-1746), and the porous substrate is preferably a porous alumina substrate. Further, cerium oxide can suppress the above-mentioned unavoidable chemical reaction if the film thickness is 5 nm or more. Further, since the oxygen permeable thin film is composed of amorphous or fine microcrystalline particles, cracks do not occur even when used at a higher temperature than before, and it is possible to have both high oxygen permeable characteristics and strength.

Further, the method for producing an oxygen permeable structure of the present invention comprises depositing cerium oxide on a porous substrate, and using a target having the composition of the oxygen permeable thin film on the cerium oxide to produce oxygen by pulse laser deposition. It is characterized in that a transparent thin film is deposited. The porous substrate is alumina porous substrate, the oxygen permeability thin film composition formula La _x Sr _1-x Ga _y
An oxygen permeable thin film represented by Fe _1-y O (where 0 <x <1, 0 <y <1) or a composition formula La _x Sr _1-x Co
It is characterized by being an oxygen permeable thin film represented by _y Fe _{1 -y} O (where 0 <x <1 and 0 <y <1). The substrate temperature during pulsed laser deposition is less than 750 ° C. According to this method, a dense oxygen-permeable thin film composed of amorphous or fine crystal grains is formed on the cerium oxide. Amorphous or fine crystal grains,
No cracks occur even when thermal shock is applied.

Therefore, according to the present invention, it is possible to provide an oxygen permeable structure having a high oxygen permeable property and a high thermal shock resistance, and a method for producing the same.

[0014]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described in detail below with reference to the drawings. FIG. 1 is a schematic cross-sectional view showing the structure of the oxygen permeable structure of the present invention. In the figure, an oxygen permeable structure 1 is composed of a porous substrate 2, a cerium oxide 3 laminated on the porous substrate 2, and an oxygen permeable thin film 4 laminated on the cerium oxide 3. The porous substrate 2 is, for example, a porous alumina substrate obtained by anodizing an Al plate.
The cerium oxide 3 is, for example, a cerium oxide represented by the composition formula CeO ₂ , and the film thickness may be 5 nm or more. The oxygen permeable thin film 4 is, for example, L having a thickness of 5 μm or less.
SGF-based oxygen permeable thin film, that is, the composition formula La _x Sr
_{1-x Ga y Fe 1-} y O ( provided that, 0 <x <1,0 <y <
1) which is an oxygen permeable thin film, and has a thickness of 5 μm or less, for example, an LSCF-based oxygen permeable thin film, that is, a composition formula La _x Sr _1-x Co _y Fe _1-y O (where 0 <x
It is an oxygen-permeable thin film represented by <1, 0 <y <1). These oxygen permeable thin films 4 are composed of amorphous or extremely fine microcrystalline particles.

To use the oxygen permeable structure 1, the oxygen permeable structure 1 is heated to about 700 ° C. and the porous substrate 2 is used.
Air of 1 atm is supplied to the side to reduce the oxygen partial pressure on the side of the oxygen permeable thin film 4 for use. Only oxygen in the air passes through the oxygen permeable structure 1.

In the oxygen permeable structure 1 of the present invention, the cerium oxide 3 can suppress an unavoidable chemical reaction between the porous substrate 2 and the oxygen permeable thin film 4. Since it is composed of crystallites or extremely fine microcrystalline particles, cracks and the like do not occur, and high oxygen permeability, high temperature use, and long life are possible.

Next, the present invention will be described in more detail based on examples. First, an oxygen-permeable structure using an LSGF-based oxygen-permeable thin film and a method for manufacturing the same will be described. An LSGF-based oxygen permeable thin film represented by the composition formula La _0.7 Sr _0.3 Ga _0.6 Fe _0.4 O _3-z (where 0 ≦ z <3), which has been reported to have high oxygen permeability in a bulk body, was prepared. Prior to the thin film production, the target was produced by the solid phase reaction method.
Raw material powder is La ₂ O ₃ (purity 99.99%), SrC
O ₃ (purity _{99.9%), Ga 2 O 3} ( purity 99.9
%) And Fe ₂ O ₃ (purity 99.99%) were used. These raw materials were weighed so as to have the respective composition ratios described above, and then mixed by ball milling. For ball milling, a pot and balls made of stainless steel were used and mixed in ethyl alcohol for 1 hour. The mixed powder is 62 MPa by hand pressing after thoroughly drying ethyl alcohol.
Was pressed and pressed into 20 mmφ pellets. The pellets were heated to 1000 ° C. at a heating rate of 300 ° C./h, held for 2 hours, and calcined. The calcined powder was coarsely pulverized in an alumina mortar and hand-mixed for 30 minutes, and then a 5 mass% PVA (polyvinyl alcohol) aqueous solution was added as a sintering aid at 5 mass% of the powder weight, and the mixture was further hand-mixed for 30 minutes. 20 mm for each calcined powder at a molding pressure of 3 ton
After powder compaction into φ pellets, cold isostatic pressing was performed at 300 MPa, and main firing was performed at 1500 ° C. for 4 hours to obtain a target. The resulting target had a density of 5.6 g / cm ³ .

A pulse laser vapor deposition apparatus was used for producing the thin film. The equipment consists of a film forming chamber and a laser generator. The film forming chamber has a vacuum pump (rotary pump, turbo molecular pump), an atmosphere gas introduction part, and the film forming chamber has a lamp heater for heating a substrate, a vacuum system (Pirani vacuum gauge, capacitance manometer), an oxygen flow controller,
It is equipped with a holder that can rotate the target and substrate. A window for introducing a laser and a window for observing the inside are provided on the outer wall of the film forming chamber. A KrF excimer laser having a wavelength of 248 nm is used as a laser light source of the laser generator, and a target in the film formation chamber is irradiated with some reflection mirrors.

When forming a film, the degree of vacuum in the film forming chamber is 5 × 1.
After reaching 0 ^-5 Pa, thin film production was started. Commercially available porous A with a diameter of 13 mm was prepared on the substrate by the anodic oxidation method.
An l ₂ O ₃ (pore size 20 nm) substrate was used. The distance between the target and the substrate was 30 to 35 mm, and the substrate temperature during film formation was from room temperature to 700 ° C. with a lamp heater. The oxygen atmosphere gas pressure was 0 to 20 Pa. First, CeO ₂ was deposited as a buffer layer for 3 minutes, and then an LSGF thin film was formed. At this time, by changing the film formation time, LS
The film thickness of the GF oxygen-permeable thin film was changed.

Using the LSGF target produced by the above solid phase sintering method and the target, an LSGF oxygen permeable thin film was produced at room temperature with a laser power of 500 mJ and an oxygen pressure of 10 Pa. FIG. 2 is a diagram showing a powder X-ray diffraction image of a target and an LSGF oxygen-permeable thin film formed by a pulsed laser deposition method. From the figure, it was found that the target has SrLaGa ₃ O ₇ as the second phase in addition to the LSGF perovskite type phase as the main phase. However, no diffraction peak was observed in the LSGF oxygen-permeable thin film, and it was confirmed that the LSGF oxygen-permeable thin film was in an amorphous state in the film thickness range of 5 to 200 nm. The substrate temperature during film formation is 700
This amorphous state was maintained even at 0 ° C.

FIG. 3 shows an amorphous LSG film formed on a cerium oxide layered on a porous substrate at room temperature for 2 hours.
It is a figure which shows the cross-sectional SEM image of an F oxygen permeable thin film. From this figure, it is confirmed that a dense oxygen-permeable thin film having a thickness of 4 μm is deposited on the porous substrate. From the fact that no crystal grains or unevenness is observed in the film, it is suggested that the film is in the amorphous state shown by the above-mentioned X-ray diffraction.

FIG. 4 shows the LSGF oxygen permeable thin film as described above.
It is a figure which shows the cross-section SEM image after heat-processing at 0 degreeC. As can be seen from the figure, crystal grains are confirmed, and it can be seen that crystallization is progressing at this temperature. When the crystallization start temperature was investigated by changing the heat treatment temperature, it was confirmed that the crystallization start temperature was around 750 ° C. Also,
This heat treatment was performed at an extremely high temperature rising rate of 700 to 800 ° C./min, but it was revealed that the LSGF oxygen-permeable thin film of the present invention was not destroyed and had high thermal shock resistance. It was This is suitable as a reformer of a fuel cell for a mobile body, which requires high-speed startability.

FIG. 5 is a diagram showing the structure of a measuring system used for measuring the oxygen transmission characteristics. A permeated oxygen measuring section 9 in which a ceramics plate 8 having a hole is hermetically fixed to the bottom of the transparent quartz tube 6 via a borosilicate glass ring 7 and a ceramics plate 8 having a hole in the bottom of the transparent quartz tube 6 are fixed. An atmospheric pressure applying unit 10 is prepared, and the sample 1 is fixed between both ceramic plates 8 via a gold ring 11. The surface of the oxygen-permeable thin film was fixed toward the permeated oxygen measuring unit 9 side. High-temperature air is sent from the atmospheric pressure applying section 10 side through the alumina tube 12. The temperature at the outlet of the alumina tube 12 was measured by the thermocouple 13 and used as the sample temperature. He gas is introduced through the alumina tube 14, and the flow rate is controlled so that the oxygen partial pressure of the permeated oxygen measuring unit 9 becomes constant. The He gas at the same flow rate as the introduced He gas was introduced into the gas chromatograph and the quadrupole gas mass spectrometer, the number of permeated oxygen molecules per unit time was measured, and the oxygen permeation flow velocity density j (O ₂ ) Ask for. The oxygen permeation flow velocity density j (O ₂ ) at each oxygen partial pressure is obtained, and the oxygen partial pressure gradient dependency of the oxygen permeation flow velocity density is measured.

FIG. 6 is a graph showing the oxygen partial pressure gradient dependency of the oxygen permeation flow velocity density of the oxygen permeation structure of the present invention using the LSGF oxygen permeation thin film. In the figure, ▲ (black triangle),
■ (black square), ● (black circle) and × are the temperature of the oxygen permeable structure at the time of measurement, 750 ° C, 800 ° C and 850, respectively.
Indicates 900 ° C and 900 ° C. As is clear from FIG. 7, the LSGF oxygen permeation structure of the present invention has a high oxygen permeation flux density at a high temperature of 750 ° C. or higher, almost independently of the oxygen partial pressure gradient. After the measurement at 750 ° C., the LSGF oxygen-permeable thin film of the present invention maintained the amorphous state or the fine crystalline state as described above. 8
Crystallization occurred after the measurement at 00 ° C or higher.
Oxygen permeation flux density is 3.6 × 10 at 750 ° C.
^It shows a high value of ^-7 mol · cm ^-2 s ^-1, and the oxygen transmission rate due to air leakage due to thin film defects (pinholes and cracks) is about 0.23% with respect to the He gas flow rate. It was Although a higher oxygen permeation flux density was obtained by setting the measurement temperature to 800 ° C or higher, a large number of cracks were introduced into the thin film during crystallization, so oxygen permeation due to leakage increased to 0.31%. did. From this, it is understood that when the thin film is in the amorphous state or the fine crystalline state, the relatively high leak resistance and the oxygen permeation flux density are compatible.

Next, an LS which is another embodiment of the present invention.
An oxygen permeable structure using a CF type oxygen permeable thin film and a method for manufacturing the same will be described. The manufacturing method and the measuring method are as described above
This is equivalent to the case of the oxygen permeable structure using the GF-based oxygen permeable thin film. _{7, La 0.6 Sr 0.4 Co 1-} x Fe x O
FIG. 3 is a diagram showing changes over time in the oxygen permeation flux density of the oxygen permeation structure of the present invention using a _3-z thin film. In the figure, ● indicates an oxygen permeable structure using a cerium oxide buffer layer, □
Shows the results of a conventional oxygen permeable structure without a cerium oxide buffer layer. As is clear from the figure, when the cerium oxide buffer layer is not used, the oxygen permeation flux density monotonously decreases with time, but when the cerium oxide buffer layer is used, the degree of decrease is extremely high. It turns out that it is gentle.

When X-ray diffraction measurement was performed on the sample after the above-described aging measurement, when the cerium oxide buffer layer was not used, Co in the LSCF thin film and Al ₂ O _{3 of the} substrate caused a chemical reaction, resulting in oxygen permeation. It was confirmed that a CoAl ₂ O ₄ phase that inhibits the above was formed. However, when cerium oxide was used as the buffer layer, formation of such a phase was not confirmed, and the cerium oxide buffer layer was
It can be seen that the chemical reaction between the F thin film and the Al ₂ O ₃ substrate is suppressed.

Although not shown, the cerium oxide buffer was used even in a sample having a larger composition ratio of Co than in the sample shown in the figure, which is more likely to form a CoAl ₂ O ₄ phase, and under higher temperature conditions. It was confirmed that a high oxygen permeability was maintained when the layer was used. In addition, when the cerium oxide buffer layer was not used, the substrate deteriorated with the formation of the CoAl ₂ O ₄ phase and showed a tendency to crack at 900 ° C. or higher.
It was confirmed that the substrate had sufficient mechanical strength and did not crack even at a high temperature of 900 to 1000 ° C.

[0028]

As can be understood from the above description, according to the present invention, the cerium oxide buffer layer suppresses the unavoidable reaction between the substrate and the oxygen permeable thin film, and also the cerium oxide buffer layer. Since the upper oxygen permeable film is composed of amorphous or fine crystal grains, cracks and the like are less likely to occur, and therefore the oxygen permeable film can be made thin, resulting in high oxygen permeable characteristics and high strength. It would be possible to provide an oxygen permeable structure. Therefore, when the present invention is applied to a moving body or the like using a fuel cell, it is extremely useful.

[Brief description of drawings]

FIG. 1 is a schematic cross-sectional view showing the configuration of an oxygen permeable structure of the present invention.

FIG. 2 is a diagram showing a powder X-ray diffraction image of a target and an LSGF oxygen-permeable thin film formed by a pulse laser deposition method.

FIG. 3 shows cerium oxide laminated on a porous substrate,
It is a figure which shows the cross-sectional SEM image of the amorphous LSGF oxygen permeable thin film formed into a film at room temperature for 2 hours.

FIG. 4 is a diagram showing a cross-sectional SEM image after heat-treating an LSGF oxygen-permeable thin film at 800 ° C.

FIG. 5 is a diagram showing a configuration of a measurement system used for measuring oxygen transmission characteristics.

FIG. 6 is a diagram showing the oxygen partial pressure gradient dependence of the oxygen permeation flow velocity density of the oxygen permeation structure of the present invention using the LSGF oxygen permeation thin film.

7 is a diagram showing changes over time of the oxygen permeation flux density of the oxygen-permeable structure of the present invention using the _{La 0.6 Sr 0.4 Co 1-x} Fe x O 3-z film.

FIG. 8 is a conceptual diagram illustrating a partial oxidation method.

FIG. 9 is a diagram showing the oxygen partial pressure gradient dependence of the electronic conductivity and ionic conductivity of an oxygen ion / electron mixed conductor.

[Explanation of symbols] 1 Oxygen permeable structure 2 Porous substrate 3 Cerium oxide 4 Oxygen permeable thin film 6 Transparent quartz tube 7 Borosilicate glass ring 8 Ceramics plate 9 Permeation oxygen measurement part 10 Atmospheric pressure application section 11 gold ring 12 Alumina tube 13 thermocouple 14 Alumina tube

Continued front page    F-term (reference) 4F100 AA17B AA19C AA23A AA33A                       BA03 BA07 BA10A BA10C                       DJ00C EH66A GB90 JA12A                       JD03A JM02A YY00A YY00B                 4K029 BA02 BA09 BA43 BA50 DB05

Claims (8)

[Claims] 1. An oxygen permeable structure comprising an oxygen permeable thin film and a porous substrate, wherein cerium oxide is sandwiched as a buffer layer between the oxygen permeable thin film and the porous substrate. body. 2. The oxygen permeable thin film has a composition formula of La _x Sr.
_{1-x Ga y Fe 1-} y O ( provided that, 0 <x <1,0 <y <
The oxygen permeable structure according to claim 1, wherein the oxygen permeable thin film has a thickness of 5 μm or less, which is represented by 1), and the porous substrate is a porous alumina substrate. 3. The oxygen permeable thin film has a composition formula of La _x Sr.
_1-x Co _y Fe _1-y O (where 0 <x <1, 0 <y <
The oxygen permeable thin film represented by 1), wherein the porous substrate is a porous alumina substrate.
The oxygen permeation structure according to. 4. The oxygen-permeable thin film is amorphous or
The oxygen permeable structure according to claim 2 or 3, which is made of fine crystal grains and has a film thickness of 5 µm or less. 5. The oxygen permeable structure according to claim 1, wherein the cerium oxide has a film thickness of 5 nm or more. 6. Preparation of an oxygen permeable structure, characterized in that cerium oxide is deposited on a porous substrate and the oxygen permeable thin film is deposited by pulsed laser deposition using a target having the composition of the oxygen permeable thin film. Method. 7. The porous substrate is an alumina porous substrate, and the oxygen permeable thin film has a composition formula of La _x Sr _1-x Ga _y.
An oxygen permeable thin film represented by Fe _1-y O (where 0 <x <1, 0 <y <1) or a composition formula La _x Sr _1-x Co
7. An oxygen-permeable thin film represented by _y Fe _{1 -y} O (where 0 <x <1 and 0 <y <1).
The method for producing an oxygen permeable structure as described in 1. 8. The substrate temperature during the pulse laser deposition is 7
The method for producing an oxygen permeable structure according to claim 6, wherein the temperature is lower than 50 ° C.