JP2021137797A - Oxygen extraction filter and material of the same, oxygen extraction device, and oxygen production method - Google Patents

Abstract

To provide a material for an oxygen extraction filter having excellent mechanical strength and an appropriate thermal expansion coefficient.SOLUTION: A material for an oxygen extraction filter is a composite material formed by sintering an oxide ion and electron mixed conductor having oxygen permeability, and an oxide ion conductor in a mixed state, and extracts oxygen in the air. The oxide ion and electron mixed conductor is LaxSr1-xCo1-yFeyO3-δ (0<x≤0.2, 0<y≤0.2). The oxide ion conductor is composed of at least one selected from samarium-doped ceria, lanthanum-doped ceria and gadolinium-doped ceria. A volume ratio of the oxide ion and electron mixed conductor to the oxide ion conductor is 20:80 to 80:20.SELECTED DRAWING: None

Description

The present invention relates to a material for an oxygen extraction filter or the like that allows only oxygen in the air (atmosphere) to permeate and extracts oxygen from the air (atmosphere).

For example, in medical settings such as hospitals, there is a demand for pure oxygen (more accurately, 99.5% or more of almost pure oxygen). This is to allow critically ill patients to inhale oxygen.

Conventionally, oxygen chemically produced in a factory is transported in a state of being contained in a cylinder and supplied to a medical site or the like.
However, this is costly, and there is an unstable factor that if the cylinder inventory is exhausted and a new cylinder cannot be transported, the patient cannot inhale oxygen.

Here, about 20% of the atmosphere is oxygen, and if oxygen is extracted from the atmosphere, the above problem can be solved. That is, there is a demand for a filter that allows only oxygen to permeate, and a material suitable for the filter is being sought.

Sr-Co oxides are known to have high oxygen permeability (particularly at high temperatures).
However, this oxide has a drawback that a phase transition of crystals is likely to occur. Therefore, it is not suitable for an oxygen extraction filter.

As disclosed in Non-Patent Document 1 and Non-Patent Document 2, La-Sr-Co-Fe-based oxides have high oxygen permeability and are less likely to undergo a phase transition of crystals. In particular, among them, it is known that an oxide having a molar ratio of La, Sr, Co, and Fe of 1: 9: 9: 1 is particularly excellent in oxygen permeability.

However, this oxide has a drawback that it has a weak mechanical strength and is not practical.
That is, in Patent Document 1, the value of the room temperature three-point bending strength of the perovskite type mixed conductor _{described by La 0.1} Sr _0.9 Co _0.9 Fe _0.1 O _{3-δ is about 3 MPa, which is a general structural ceramic.} It has been pointed out that it is significantly lower than that of certain alumina (400 MPa), partially stabilized zirconia (1000 MPa), mullite (200 MPa), silicon nitride (800 MPa), and the like.
Therefore, this oxide is also unsuitable for an oxygen extraction filter.

Further, it is basically impossible to use the oxygen extraction filter alone, and gold or silver is applied to the oxygen extraction device (the device body) formed of a metal such as stainless steel having heat resistance. It is supposed to be attached and used as an adhesive.
Each material has the property of expanding and contracting depending on the temperature, and the degree (coefficient of thermal expansion) differs depending on each material.

However, the coefficient of thermal expansion of the La-Sr-Co-Fe-based oxide is considerably larger than the coefficient of thermal expansion of stainless steel or the like. That is, in Patent Document 2, where the coefficient of linear thermal expansion of stainless steel (SUS310S) is about 17.5 ppm / ° C., the LSCF-based perovskite type mixture represented by _{La 0.2} Sr _0.8 Co _0.8 Fe _0.2 O _3-δ It has been pointed out that the average coefficient of linear thermal expansion of the conductor from room temperature to 800 ° C. is about 26 ppm / ° C., which is extremely high.
Therefore, when the filter formed by this oxide is attached to the oxygen extraction device (device body) made of stainless steel, the expansion and contraction of the filter due to temperature changes is caused by the metal as an adhesive and the device body (device body). There is also a drawback that it does not match the expansion and contraction of the corresponding member) and is damaged.
Again, this oxide is unsuitable for oxygen extraction filters.

Japanese Unexamined Patent Publication No. 2003-210952 JP-A-2002-020180

Yasutake Teraoka "Chemistry Letters" 1985 pp.1743-1746 Yasutake Teraoka "Journal of the Japanese Society of Chemistry" 1988 (7) pp.1084-1089 Yasutake Teraoka "Journal of the Japan Ceramic Society" 1989 Vol.97 No.4 pp.467-472

An object of the present invention is to provide a material for an oxygen extraction filter or the like, which has excellent mechanical strength and an appropriate coefficient of thermal expansion (close to the coefficient of thermal expansion of a predetermined metal).

The present inventor presents oxygen in which a composite material formed by sintering an oxide ion / electron mixed conductor having oxygen permeability and an oxide ion conductor in a mixed state extracts oxygen in the air. They found that it was suitable as a material for an extraction filter.
That is, it is suitable when the oxide ion conductor has a reinforcing function and a function of lowering the coefficient of thermal expansion.

The "oxide ion / electron mixed conductor" refers to a material capable of conducting both oxide ions and electrons. The "oxide ion conductor" refers to a material capable of conducting oxide ions.

Examples of the oxide ion / electron mixed conductor (hereinafter, also simply referred to as “mixed conductor”) include La-Sr-Co-Fe-based perovskite-type oxides. Regarding the molar ratio of La, Sr, Co, and Fe, it is desirable that x: 1-x: 1-y: y and 0 <x ≦ 0.2, 0 <y ≦ 0.2.

The oxide ion conductor preferably comprises at least one selected from, for example, samarium-doped ceria, lanthanum-doped ceria, and gadolinium-doped ceria.

The volume ratio of the mixed conductor to the oxide ion conductor is preferably 20:80 to 80:20.
Among them, the volume ratio of the lower limit of the mixed conductor and the upper limit of the oxide ion conductor is more preferably 40:60. Further, the volume ratio of the upper limit of the mixed conductor and the lower limit of the oxide ion conductor is more preferably 60:40. Further, the volume ratio of the lower limit of the mixed conductor and the upper limit of the oxide ion conductor, or the upper limit of the mixed conductor and the lower limit of the oxide ion conductor is more preferably 50:50.

A suitable oxygen extraction filter is formed by any of the oxygen extraction filter materials described above. That is, it becomes suitable as a filter by being made to have a predetermined size and thickness.

Further, by providing the above-mentioned oxygen extraction filter, a suitable oxygen extraction device is formed. For example, in the main body of the device in which a flow path from the air inflow pipe to the oxygen outflow pipe is formed such that an air inflow pipe and an oxygen outflow pipe are connected to the housing, the above-mentioned oxygen is formed in the middle of the flow path. An extraction filter is provided. Based on the oxygen partial pressure difference generated between the space on the upstream side and the space on the downstream side of the oxygen extraction filter, the oxygen in the air on the upstream side passes through the oxygen extraction filter that allows only oxygen to permeate. It will flow to the downstream side.
In this way, oxygen is extracted from the air (atmosphere) and oxygen is produced.

The composite material (material for oxygen extraction filter) of the present invention is suitable as an oxygen extraction filter because it has excellent oxygen permeability, excellent mechanical strength, and a coefficient of thermal expansion close to the coefficient of thermal expansion of a predetermined metal. be. Then, the oxygen extraction filter (an oxygen extraction device and an oxygen production method using the oxygen extraction filter) enables efficient oxygen extraction (production).

It is sectional drawing which shows schematicly the oxygen extraction apparatus using the oxygen extraction filter which is an embodiment of this invention. It is a figure which shows schematic (mostly a cross section) of the apparatus which measures the oxygen permeation rate in an Example and a comparative example of this invention.

Next, an embodiment of the present invention will be described.
In this material for oxygen extraction filter (oxygen extraction filter), a mixture of an oxide ion / electron mixed conductor (mixed conductor), which is an oxide having oxygen permeability, and an oxide ion conductor is sintered. It is formed.

[Mixed conductor]
A typical example of a mixed conductor is a La-Sr-Co-Fe-based (also referred to as "LSCF-based") perovskite-type oxide.
This is also referred to as _{La x} Sr _1-x Co _1-y F _y O _3-δ. Note that δ is a value determined so as to satisfy the charge neutrality condition. The preferred range of x and y is 0 <x ≦ 0.2, 0 <y ≦ 0.2.
Among them, x = 0.1 and y = 0.1 are particularly preferable.
That is, La _0.1 Sr _0.9 Co _0.9 Fe _0.1 O _3-δ . This is also referred to as "LSCF1991" for convenience.

[Manufacture of LSCF-based perovskite-type mixed conductor powder]
The LSCF-based perovskite-type mixed conductor powder is obtained as follows.
Lanthanum oxide (La ₂ O ₃ ), strontium carbonate (SrCO ₃ ), cobalt oxide (Co ₃ O ₄ ), ferric oxide (Fe ₂ O ₃ ) are weighed to a predetermined composition, and water, alcohol, A wet ball mill is carried out for 16 to 120 hours using a solvent such as acetone.
Next, the powder obtained by drying this mixture is calcined at 800 to 1200 ° C. for 2 to 16 hours and pulverized to obtain a powder of an LSCF-based perovskite type mixed conductor having an average particle size of 0.5 to 5.0 μm. To get.

[Oxide ion conductor]
The oxide ion conductor is an oxide having oxide ion conductivity, which increases the mechanical strength without impairing the oxygen permeability of the mixed conductor and appropriately increases the coefficient of thermal expansion (linear thermal expansion coefficient). A material that is effective for making a product is preferable.
Typical examples thereof are samarium-doped ceria (SDC), lanthanum-doped ceria (LDC), and gadolinium-doped ceria (GDC). Of these, one type may be used, or two or more types may be used.
The addition ratio of the rare earth element to be doped is preferably about 5 to 30 mol%, more preferably 5 to 20 mol%. Oxide ion conductivity is very good at about 20 mol%.

Samarium-doped ceria (SDC) is also referred to as _{Sm x} Ce _1-x O _2-δ. Note that δ is a value determined so as to satisfy the charge neutrality condition (the same applies hereinafter). The range of x is 0 <x <1. When x = 0.2, it is Sm _0.2 Ce _0.8 O _2-δ . This is also referred to as "SDC20" for convenience.
Lanthanum-doped ceria (LDC) is also referred to as _{La x} Ce _1-x O _2-δ. The range of x is 0 <x <1. When x = 0.07, it is La _0.07 Ce _0.93 O _2-δ . This is also referred to as "LDC07" for convenience.
Gadolinium-doped ceria (GDC) is also referred to as _{Gd x} Ce _1-x O _2-δ. The range of x is 0 <x <1. When x = 0.2, it is Gd _0.2 Ce _0.8 O _2-δ . This is also referred to as "GDC20" for convenience.

[Manufacture of oxide ion conductor powder]
The oxide ion conductor powder is obtained as follows.
Weigh cerium oxide and metal oxides of La, Sm, and Gd doped with cerium oxide so as to have a predetermined composition, and carry out a wet ball mill for 16 to 120 hours using a solvent such as water, alcohol, or acetone. ..
Then, the powder obtained by drying this mixture is calcined at 1000 to 1400 ° C. for 2 to 16 hours and pulverized to obtain a powder of an oxide ion conductor having an average particle size of 0.5 to 5.0 μm. ..

[Manufacturing of composite materials]
The LSCF-based perovskite-type mixed conductor powder and the oxide ion conductor powder are weighed so as to have a predetermined composition, and a wet ball mill is carried out for 16 to 120 hours using a solvent such as water or alcohol.
Next, an organic binder is added to the powder obtained by drying this mixture so as to be 3 to 10% by weight and kneaded, and then uniaxial molding is performed using a die, and further CIP molding is performed.
The molded product thus obtained is fired at a firing temperature of 1200 to 1300 ° C. for 2 to 10 hours to obtain a sintered body of a composite material.

[Test specimen for evaluation of composite material]
Various tests can be performed on the composite material (filter material) manufactured as described above as described later, and the test piece at that time is manufactured as follows.

(1) Test body for measuring thermal expansion coefficient ・ Test body for evaluating oxygen permeation performance A die having a diameter of 25 mm is used for uniaxial molding in the production of the above-mentioned composite material.
Then, the sintered body of the composite material obtained as described above is cut and polished so as to have a size of about 5 mm × 5 mm × 20 mm to prepare a test body for measuring the coefficient of linear thermal expansion.
Similarly, the sintered body of the composite material is cut and polished to a thickness of 1 mm to prepare a test body for evaluating oxygen permeation performance.

(2) Specimen for strength test A 70 × 700 mm square die is used for uniaxial molding in the production of the above-mentioned composite material.
Then, the sintered body of the composite material obtained as described above is cut and polished so as to have a size of about 4 mm × 3 mm × 50 mm to obtain a test body for strength test.

[Oxygen extraction filter]
Using the above-mentioned composite material (material for oxygen extraction filter) as a material, the material is made into a predetermined size and thickness to form an oxygen extraction filter.
As shown in FIG. 1, an oxygen extraction filter is attached to the main body of the device and used as an oxygen extraction device.
The apparatus main body (reference numeral omitted) includes a housing 10, a compressed air inflow pipe 20, a holder 30, and an oxygen outflow pipe 40. The main body of the device is made of heat-resistant stainless steel (SUS310S).
The housing 10 has a cylindrical shape with both ends closed. The housing 10 is accompanied by a heating mechanism (not shown).
The compressed air inflow pipe 20 (downstream end thereof) is connected to the upstream end portion (upstream through hole 12 thereof) of the housing 10.
In this way, a flow path of compressed air inflow pipe 20 → housing 10 → oxygen outflow pipe 40 is formed.
The holder 30 is arranged inside the housing 10 (in the middle of the above-mentioned flow path). The holder 30 has a disk shape, and a circular hole 34 is formed in the center thereof.
An annular protrusion-shaped filter installation portion 32 is formed on the edge of the disk-shaped holder 30, and an oxygen extraction filter 50 is attached to the filter installation portion 32. At that time, gold or silver (in a molten state) is used as an adhesive, and the oxygen extraction filter 50 is adhered to the filter installation portion 32.
The oxygen outflow pipe 40 (upstream end thereof) is connected to the holder 30 (circular hole 34 thereof). The oxygen outflow pipe 40 extends in the housing 10 toward the downstream side, penetrates the housing 10 (the downstream through hole 14 thereof), and is exposed to the outside of the housing 10. The downstream end of the oxygen outflow pipe 40 is open to the atmosphere. Alternatively, the pressure is further reduced to a pressure lower than that. In this way, the pressure inside the oxygen outflow pipe 40 is set to 1 atm (atmospheric pressure) or less.

Then, the oxygen extraction device (oxygen production method) is used as follows.
The housing 10 and everything inside it (including the oxygen extraction filter 50) is maintained at a temperature of 700-900 ° C.
Compressed air is supplied into the housing 10 through the compressed air inflow pipe 20. The pressure of compressed air is 0.2 to 0.8 MPa (about 2 atm to about 8 atm), and a typical example thereof is 0.5 MPa (about 5 atm). The compressed air is supplied at a flow rate of 0.05 to 5.00 liters / second and flows into the housing 10.
Then, based on the oxygen partial pressure difference generated between the space on the upstream side and the space on the downstream side of the oxygen extraction filter 50, in the oxygen extraction filter 50, only oxygen in the air in the housing 10 permeates and oxygen flows out. Oxygen flows out through the tube 40.
In this way, only oxygen is extracted (manufactured) from the air.

Specific examples of the present invention will be described below. The present invention is not limited to these examples.
[Experiment on molar ratio of La, Sr, Co, Fe in mixed conductor]
As described above, the La-Sr-Co-Fe-based perovskite-type oxide is preferable as the mixed conductor, but the molar ratio of La, Sr, Co, and Fe was tested.
When _{x and} y in La x Sr _1-x Co _1-y F _y O _3-δ took various values, the oxygen permeation rate was measured.

Table 1 shows the experimental results.
The horizontal axis is the value of x, and the vertical axis is the oxygen permeation rate.
Further, ▲ indicates a case where the value of y is 0.1, ◯ indicates a case where the value of y is 0.2, and □ indicates a case where the value of y is 0.3.

According to this, if the oxygen permeation rate is preferably 0.15 μmol / (cm ² · sec) or more, 0 <x ≦ 0.2 is preferable for x. On that premise, 0 <y ≦ 0.2 is preferable for y.
The oxygen permeation rate was measured as described later.

[Experiment on the volume ratio of mixed conductors and oxide ion conductors in composite materials]
Next, various experiments were conducted on the volume ratio of the mixed conductor and the oxide ion conductor in the composite material (material for oxygen extraction filter) to obtain Examples 1 to 8 and Comparative Examples 1 to 3 below.
Table 2 shows the experimental results.

(Mixed conductor)
In all Examples and Comparative Examples, a perovskite-type oxide (LSCF1991) of _{La 0.1} Sr _0.9 Co _0.9 Fe _0.1 O _{3-δ was used as the mixed conductor.}
The firing temperature at the time of producing the mixed conductor was 1000 ° C. in Examples 1 to 3, 7 and 8 and Comparative Examples 1 to 3, and 1200 ° C. in Examples 4 to 6.

(Oxide ion conductor)
In Examples 1 to 4, 7 and 8, and Comparative Examples 2 and 3, samarium-doped ceria (SDC) was used as the oxide ion conductor. More specifically, it is Sm _0.2 Ce _0.8 O _2-δ , and is also referred to as “SDC20” as described above.
In Example 5, lanthanum-doped ceria (LDC) was used as the oxide ion conductor. More specifically, it is La _0.07 Ce _0.93 O _2-δ , and is also referred to as “LDC07” as described above.
In Example 6, gadolinium-doped ceria (GDC) was used as the oxide ion conductor. More specifically, it is Gd _0.2 Ce _0.8 O _2-δ , and is also referred to as “GDC 20” as described above.

(Volume ratio)
The volume ratio of the mixed conductor and the oxide ion conductor is as follows.
In Example 1, it is 80:20, and in Example 2, it is 60:40. In Examples 3 to 6, it is 50:50. In Example 7, it is 40:60, and in Example 8, it is 20:80.
On the other hand, it is 100: 0 in Comparative Example 1 and 90:10 in Comparative Example 2. Further, in Comparative Example 3, it is 10:90.
In each case, the firing temperature was 1250 ° C.

According to this, in Examples 1 to 8, good or generally good results were obtained in all of the mechanical strength (room temperature 3-point bending strength), the average coefficient of linear thermal expansion, and the oxygen permeation rate.
On the other hand, in Comparative Examples 1 and 2, the mechanical strength was weak and the average coefficient of linear thermal expansion was too high. Further, in Comparative Example 3, the average coefficient of linear thermal expansion was too low.
It will be analyzed in detail below.

Regarding the mechanical strength, the bending strength at three points at room temperature was measured based on R1601 of JIS (Japanese Industrial Standards).
In Examples 3 to 8 and Comparative Example 3, the mechanical strength (room temperature 3-point bending strength) is 100 MPa or more, which is good as a filter material. Further, it is 85 MPa in Example 1 and 95 MPa in Example 2, both of which are generally good (Example 2 can be said to be a considerably better one among them).
On the other hand, in Comparative Examples 1 and 2, the mechanical strength is 65 MPa or less, which is not suitable as a filter material.

The average coefficient of linear thermal expansion is the rate of linear expansion per 1 ° C increase when the temperature rises from 20 ° C (room temperature) to 900 ° C.
As described above based on FIG. 1, it is assumed that the main body of the oxygen extraction device used in a high temperature state of 700 to 900 ° C. is made of stainless steel (SUS310S having heat resistance) or the like. It is assumed that a filter is attached to the apparatus main body (holder 30) using molten gold or silver as an adhesive.
The coefficient of linear thermal expansion (room temperature to 900 ° C) of stainless steel (SUS310S) is 17.9 ppm / ° C, and the coefficient of linear thermal expansion of gold and silver (room temperature to each melting temperature of 1064 ° C and 960 ° C) is Where the values are 14.2 ppm / ° C and 18.9 ppm / ° C, respectively, the filter must also have a coefficient of linear thermal expansion close to those values (particularly, the coefficient of linear thermal expansion of gold or silver, which is an adhesive). be.
From this point of view, the coefficient of linear thermal expansion in Examples 1 to 8 is close to the coefficient of linear thermal expansion of the above-mentioned metal (including the metal as an adhesive), and is good as a material for a filter. Among them, Examples 2 to 6 have a coefficient of thermal expansion close to that of stainless steel (SUS310S) or silver, and can be said to be particularly good as a filter material when silver is used as an adhesive. Examples 7 and 8 have a coefficient of thermal expansion close to that of gold, and can be said to be particularly good as a filter material when gold is used as an adhesive.
On the other hand, in Comparative Examples 1 and 2, the coefficient of linear thermal expansion of the above metal is considerably larger than that of the metal, which is unsuitable. Further, in Comparative Example 3, it is considerably smaller than the coefficient of linear thermal expansion of the above metal, which is unsuitable.

The oxygen permeation rate was measured using the apparatus shown in FIG.
The device has a pair of alumina cylinders (first cylinder 60A, second cylinder 60B), both of which are arranged in series.
A disk-shaped macerite 68, a test body 80 (oxygen extraction filter), and a gold ring 69 are sandwiched between the first cylinder 60A and the second cylinder 60B in an airtight state. A through hole (reference numeral omitted) is formed in the central portion of the macerite 68.
A first valve device 62A is provided at the base end of the first cylinder 60A, and an air inflow pipe 64A is provided so as to penetrate the first valve device 62A. The air inflow pipe 64A has a smaller diameter than the first cylinder 60A, extends concentrically with the first cylinder 60A, and extends to the inside of the first cylinder 60A. The first valve device 62A is also provided with a first outflow pipe 66A, and a flow path having an annular cross section between the first cylinder 60A and the air inflow pipe 64A is directed toward the base end portion of the first cylinder 60A. The flowing gas flows out through the first outflow pipe 66A.
Similarly, a second valve device 62B is provided at the base end of the second cylinder 60B, and a helium inflow pipe 64B is provided so as to penetrate the second valve device 62B. The helium inflow pipe 64B has a smaller diameter than the second cylinder 60B, extends concentrically with the second cylinder 60B, and extends to the inside of the second cylinder 60B. The second valve device 62B is also provided with a second outflow pipe 66B, and the flow path of the annular cross section between the second cylinder 60B and the helium inflow pipe 64B is directed toward the base end portion of the second cylinder 60B. The flowing gas flows out through the second outflow pipe 66B. A gas chromatograph is provided on the downstream side of the second outflow pipe 66B.
The electric furnace 70 heats the portion between the downstream portion of the first cylinder 60A and the downstream portion of the second cylinder 60B to a high temperature (900 ° C.).

Then, the atmospheric pressure air naturally flows into the first cylinder 60A through the air inflow pipe 64A.
On the other hand, helium is made to flow into the second cylinder 60B through the helium inflow pipe 64B. In this way, the gas other than helium in the second cylinder 60B is made to flow out together with helium through the second outflow pipe 66B.
Regarding the air in the first cylinder 60A, only oxygen thereof passes through the test body 80, oxygen flows into the second cylinder 60B, and helium and oxygen flow out through the second outflow pipe 66B.
The amount of oxygen outflow is measured by a gas chromatograph, and the oxygen permeation rate (mol / (cm ² · sec)) in the test piece 80 is calculated.

As a result, in Examples 1 to 6, the oxygen permeation rate was 0.10 μmol / (cm ² · sec) or more, which is good. In Examples 7 and 8, the oxygen permeation rate is 0.08 μmol / (cm ² · sec) or more and less than 0.10 μmol / (cm ² · sec), which is generally good.

Taken together, it can be said that the volume ratio of the mixed conductor to the oxide ion conductor is preferably 20:80 to 80:20.
Among them, the volume ratio of the lower limit of the mixed conductor and the upper limit of the oxide ion conductor is more preferably 40:60, and the volume ratio of the upper limit of the mixed conductor and the lower limit of the oxide ion conductor is 60:40. It can be said that it is more preferable.
Further, it can be said that the volume ratio of the lower limit of the mixed conductor and the upper limit of the oxide ion conductor or the upper limit of the mixed conductor and the lower limit of the oxide ion conductor is more preferably 50:50.

Claims (7)

It is a composite material formed by sintering an oxide ion / electron mixed conductor having oxygen permeability and an oxide ion conductor in a mixed state.
A material for an oxygen extraction filter that extracts oxygen in the air. The material for an oxygen extraction filter according to claim 1.
The oxide ion / electron mixed conductor
A La-Sr-Co-Fe-based perovskite-type oxide.
The molar ratio of La, Sr, Co, Fe is x: 1-x: 1-y: y, and 0 <x ≦ 0.2, 0 <y ≦ 0.2.
Material for oxygen extraction filter. The oxygen extraction filter material according to claim 1 or 2.
The oxide ion conductor comprises at least one selected from samarium-doped ceria, lanthanum-doped ceria and gadolinium-doped ceria.
Material for oxygen extraction filter. The oxygen extraction filter according to any one of claims 1 to 3.
The volume ratio of the oxide ion / electron mixed conductor to the oxide ion conductor is 20:80 to 80:20.
Material for oxygen extraction filter. An oxygen extraction filter formed of the oxygen extraction filter material according to any one of claims 1 to 4. An oxygen extraction device provided with the oxygen extraction filter according to claim 5. An oxygen production method for producing oxygen by extracting oxygen from the atmosphere using the oxygen extraction filter according to claim 5.

Images