JPH11246220A - Perovskite type multiple oxide, its production and solid oxide electrolyte fuel cell using that - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a perovskite multiple oxide which suppresses the solid phase reaction on the interface with a solid electrolyte, which shows improved heat resistance and durability while keeping the good catalytic activity, and which realizes power generation in a low temp. region, and to provide the producing method of the perovskite multiple oxide, and a solid oxide electrolyte fuel cell and its electrode by using the oxide above described. SOLUTION: In a perovskite multiple oxide expressed by the general formula of ABCO3 , two kinds of specified elements A', A'' are assigned in the A site, two kinds of specified elements B', B'' are assigned in the B site, and further, Mg which functions as a sintering assistant is assigned in the C site. Therefore, the perovskite multiple oxide of this invention is expressed by A'1-x A''x B'1-y B ''y CO3 . In the formula, A' is a lanthanoid element, A'' is a lonthanoid element except for A', B' is an aluminum group element, B'' is a platinum group element, and C is an alkaline earth element, and (x) and (y) satisfy 0<x<1 and 0<y<1, respectively. The multiple oxide is used to produce an electrode material or the like.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a novel perovskite-type composite oxide that behaves as an oxide-mixed ion conductive material and a method for producing the same, and more particularly, to a method using a hydrogen carbonate-based liquid fuel or natural gas. In a solid electrolyte fuel cell that generates electric power by using a perovskite-type composite oxide that can be used as an air electrode material for a solid electrolyte such as zirconia or ceria, and has a catalytic action, a method for producing the same, an electrode catalyst using the same, and an electrode And a fuel cell.

[0002]

2. Description of the Related Art Conventionally, noble metals such as platinum, rhodium and palladium have been used as an air electrode material of a solid oxide fuel cell for generating electricity using a hydrocarbon-based liquid fuel or natural gas. And the characteristics deteriorated depending on the use environment. In particular, when it is also used as an air electrode catalyst of a solid oxide fuel cell,
Since it is assumed that the air electrode material is used at a temperature of about 000 ° C., an air electrode material having excellent heat resistance is also desired from the viewpoint of durability. The use of a perovskite-type composite oxide having high mixed ionic conductivity as an air electrode material has been studied.

Under these circumstances, recently, as highly active perovskite-type composite oxides, LaCoO ₃ and LaM
nO ₃ , LaSr _0.8 Mn _0.2 O ₃ , LaGaO _3, etc. have been reported by the National Institute of Materials Technology, the University of Tokyo Engineering, the Central Research Institute of Electric Power Industry, etc. (Preprint of 97th Autumn Meeting of the Institute of Electrical Chemistry, Tokyo, Japan) . Japanese Unexamined Patent Publication (Kokai) No. 5-139750 discloses an oxide superionic conductive material represented by A ₃ B ₂ XO ₈ (a typical example is Ba ₃ Sc ₂₎ from Nippon Telegraph and Telephone Corporation.
ZrO ₈ ) has been proposed.

[0004]

However, even with the use of these highly active perovskite-type composite oxides, the temperature range in which ionic conduction develops is still 800 ° C. or higher, and the ionic conduction is not maintained for a long time in a high temperature range or a reducing atmosphere. When used, the zirconia-based or ceria-based solid electrolyte reacts with the perovskite-type composite oxide in the case of such a highly active material,
There have been problems such as an increase in resistance at the solid electrolyte / perovskite-type composite oxide interface and occurrence of structural defects due to partial omission and the like, and as a result, power generation efficiency of the fuel cell is reduced.

When a perovskite-type composite oxide is used as an air electrode material for a fuel cell, its catalytic action and electric conductivity are particularly utilized. In this case, an oxygen ion conductor, that is, a solid electrolyte is used. While reducing the interfacial resistance between the air electrode material and ensuring the adhesion,
It is necessary to suppress a chemical reaction at the solid electrolyte / air electrode material interface or separation due to thermal stress.

[0006] The present invention has been made in view of such problems of the prior art, and an object thereof is to suppress a solid-phase reaction at an interface with a solid electrolyte and to provide a good catalytic action. A perovskite-type composite oxide that can improve heat resistance and durability while maintaining power and realize power generation at low temperatures.
An object of the present invention is to provide a method for producing the same, a solid oxide electrolyte fuel cell using the same, and an electrode thereof.

[0007]

Means for Solving the Problems The present inventors have made intensive studies to solve the above-mentioned problems, and as a result, have found that a perovskite-type composite oxide represented by the general formula ABCO ₃ using a specific metal element such as doping with Mg. A perovskite-type composite oxide that effectively controls the lattice defect of the A site that improves the ionic conductivity and the valency of the B site atom that performs the catalytic action, and expresses the ionic conductivity in a low temperature range Were found to solve the above problem, and the present invention was completed.

That is, the perovskite-type composite oxide of the present invention has the following general formula (1): A ′ _1−x A ″ _x B ′ _1−y B ″ _y CO ₃ (1) A ′ is a lanthanoid element, A ″ is a lanthanoid element other than A ′, B ′ is an aluminum group element, B ″ is a platinum group element, C is an alkaline earth metal element, and x is 0 <
x <1, y indicates a number satisfying 0 <y <1. ).

Further, the electrode material of the present invention is an electrode material used for an electrode of a solid oxide electrolyte fuel cell,
It is characterized by containing a perovskite-type composite oxide as described above. Further, the electrode catalyst of the present invention is an electrode catalyst used for an electrode of a solid oxide electrolyte fuel cell, and is characterized by containing the above-described perovskite-type composite oxide.

Further, the fuel cell electrode of the present invention is an electrode used for a solid oxide electrolyte fuel cell,
It is characterized by carrying the above-mentioned electrode catalyst. Also,
A solid oxide electrolyte fuel cell according to the present invention includes an air electrode containing the above electrode material.

Further, in the method for producing a perovskite complex oxide of the present invention, when producing the perovskite complex oxide as described above, various metal elements constituting the perovskite complex oxide represented by the above formula (1) A hydrothermal reaction with the nitrate or carbonate of the above to obtain a monooxycarbonate, and firing the obtained monooxycarbonate in the air.

Further, according to the method for producing an electrode for a fuel cell of the present invention, when producing an electrode for a solid oxide electrolyte fuel cell comprising the above-mentioned electrode material, the electrode material is calcined in air. Then, the obtained temporarily sintered powder is applied to a solid electrolyte substrate, and then fired in air.

[0013]

According to the present invention, in the perovskite-type composite oxide represented by the general formula ABCO ₃ , the A site is provided with two predetermined elements A ′ and A ″, and the B site is provided with two types of B ′ and B ″. The predetermined element was further provided with Mg functioning as a sintering aid at the C site. As a result, A that improves ionic conductivity
The lattice defects of the site and the valence of the B-site element having a catalytic action and making an important contribution to the air electrode, particularly the valence of Pt and Pd, are effectively controlled to enhance the conduction characteristics between the electron-ion mixed conductor. The air electrode characteristics are improved. In addition, since the solid-state reaction between the perovskite-type composite oxide and the solid electrolyte in contact with the perovskite-type composite oxide is suppressed, the durability and heat resistance of the composite oxide that can behave as an air electrode are improved, and Low temperature operation becomes possible.

That is, in the present invention, the valence of the B-site metal element is effectively controlled by changing the molar ratio of each metal at the A site of the perovskite-type composite oxide which behaves as an ion conductive material. As a result, the electronic state is controlled. In addition, by constructing a perovskite structure having lattice defects at the A site, the ability to release and absorb oxygen is improved. As a result, the internal resistance at the solid electrolyte / air electrode (catalyst) interface is reduced, and the operating temperature can be reduced. I can do it. Furthermore, durability and heat resistance can be improved by the sintering suppressing effect of the perovskite-type composite oxide itself.

In addition, as a result of introducing the above-described lattice defects, sorbed oxygen generally important for oxygen transfer can be increased. The sorbed oxygen includes (a) oxygen (α-oxygen) which is desorbed in a wide temperature range of 800 ° C. or less and sorbs into oxygen vacancies generated by partial substitution of A-site ions;
(B) There are two types of oxygen (β-oxygen) which desorb in a sharp peak at around 820 ° C. and correspond to the reduction of the B-site element to a lower valence. Since Pt and Pd existing in the metal are stabilized, the mobility of oxygen is improved in a wide temperature range.

Further, after the perovskite-type composite oxide of the present invention and alumina or silica sol are mixed and pulverized to form a slurry, the slurry is applied on a solid electrolyte substrate and sintered, whereby the sintering aid existing in the structure is obtained. Due to the synergistic effect with the material Mg, it has strong adhesion to the solid electrolyte substrate,
It is possible to obtain a fuel cell air electrode that exhibits stable performance with respect to a heat cycle caused by the start / stop of the fuel cell and also has an electrode catalytic action.

[0017]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the perovskite-type composite oxide of the present invention will be described in detail. As described above, the perovskite-type composite oxide of the present invention functions as an oxide composite ion-conductive material, and specifically, can be used also as an electrode catalyst and an electrode material in a solid oxide electrolyte fuel cell. It is suitable for forming an air electrode of such a fuel cell.

The perovskite-type composite oxide of the present invention comprises:
The following general formula (1): A ′ _1−x A ″ _x B ′ _1−y B ″ _y CO ₃ (1) (where A ′ is a lanthanoid element and A ″ is a lanthanoid element other than A ′) , B ′ are an aluminum group element, B ″ is a platinum group element, C is an alkaline earth metal element, and x is 0 <
x <1, y indicates a number satisfying 0 <y <1. ). Specifically, La is A for A ′, and G is A for A ″.
d and / or Dy, B ′ is Al, B ″ is P
Mg is preferable as t and / or Pd and C. Also,
In the formula (1), x is 0 <x ≦ 0.5, and y is 0 <y ≦
It is preferable that the number satisfies 0.2, and x is 0.5
If y exceeds 0.2, and if y exceeds 0.2, no improvement in the effect can be expected, which is not preferable.

Next, a method for producing the perovskite-type composite oxide of the present invention will be described. This composite oxide is prepared by mixing nitrates or carbonates of various metals represented by the above formula (1) at a predetermined stoichiometric ratio, and adding nitrate to a solution of ammonium hydrogencarbonate when nitrate is used as a starting salt. Then, once converted to a carbonate, a monooxycarbonate is synthesized by a hydrothermal reaction in heated steam. If the starting salt is a carbonate, the monooxycarbonate is dispersed in pure water and then subjected to hydrothermal reaction in heated steam to produce a monooxycarbonate. It is obtained by synthesizing a carbonate and then calcining the obtained monooxycarbonate in air. Therefore, various constituent metal elements shown in the formula (1), that is, La, Gd, Dy, Pt
And Pd can be said to be derived from these nitrates or carbonates.

Hereinafter, a typical example of the above-mentioned production method will be described. First, dinitrodiaminoplatinum diluted to about twice the amount with pure water in a mixed solution of La nitrate, Gd nitrate or Dy nitrate, Al nitrate and Mg nitrate is described. Add the Pd nitrate or dinitrodiamino Pd solution and mix well with stirring. Next, this mixed solution is added to ammonium hydrogen carbonate dissolved and stirred in pure water in an autoclave in advance. After adding the entire amount, about 110 to 120 ° C in an autoclave,
Steam with a vapor pressure of 3 kg / cm ² is introduced in a sealed state.
When the internal pressure of the autoclave reaches about 1.1 to 1.2 kg / cm ^{2, the} amount of introduced steam is adjusted, and the reaction is continued for 2 to 3 hours. The reaction is terminated about 0.4 to 0.5 hours after the introduction of steam is no longer necessary. After completion of the reaction, filtration, washing, and drying are performed, and the air is filtered for about 5 hours.
By baking at 00 to 600 ° C. for 3 to 5 hours, a perovskite-type composite oxide of the present invention is obtained.

Next, the electrode catalyst, electrode material and air electrode for a fuel cell of the present invention will be described. As described above, the electrode catalyst and the electrode material of the present invention contain the perovskite-type composite oxide represented by the general formula (1). Further, the air electrode of the present invention uses the electrode catalyst of the present invention on the electrode material of the present invention or another electrode material, or uses only the electrode material of the present invention or is mixed with other materials. Can be formed.

Here, the above-mentioned electrode catalyst, electrode material and air electrode are in contact with the solid electrolyte in a high temperature solid electrolyte fuel cell using a solid electrolyte such as zirconia or ceria, preferably yttrium partially stabilized diconia. used. When the perovskite-type composite oxide of the present invention is used as an electrode catalyst, specific examples of the electrode material other than the electrode material of the present invention include zirconia and titania.

Further, the air electrode of the present invention can be prepared by applying the perovskite composite oxide to a solid electrolyte substrate and then firing in air. At this time, the perovskite composite oxide may be used alone, or may be mixed with alumina or silica sol. By using such a mixture, a synergistic effect of sintering aid components Mg and alumina can be obtained, It is possible to coat the solid electrolyte substrate with strong adhesion, and it is possible to obtain a fuel cell that realizes more stable operation.

Typically, the perovskite-type composite oxide powder is pulverized and mixed with a hydrochloric acid sol containing 10% by weight or less of alumina or silica in a planetary ball mill to obtain a slurry. After being applied to the electrolyte substrate, it is sintered at about 800 to 850 ° C. in the air to obtain the air electrode of the present invention. The content of alumina and zirica was set to 10% by weight or less because
If it exceeds 0% by weight, the amount of perovskite component is relatively reduced, which is not preferable. The reason for using the hydrochloric acid sol is to take into account the effect of the sintering aid of Cl ^- ions.

[0025]

EXAMPLES Hereinafter, the present invention will be described in more detail with reference to Examples and Comparative Examples, but the present invention is not limited to these Examples.

(Example 1) The ratio of each element is La 0.9 mol, Gd 0.1 mol, Al 0.95 mol, Pd 0.05
The nitrate of each element was mixed so as to be 1.0 mol and 1.0 mol of Mg. That is, lanthanum nitrate _{[La (NO 3) 3 ·} 6H
₂ O] _389.6g, gadolinium nitrate [Gd (NO _3)
3 · 6H ₂ O] 45.1g, aluminum nitrate [Al (N
_{O 3) 3 · 9H 2 O} ] 356.4g, palladium nitrate [P
d (NO ₃ ) ₂ + H ₂ O] 11.5 g + 11.5 g, magnesium nitrate [Mg (NO ₃ ) ₂ .6H ₂ O] 256.4
g was mixed with 1 L of pure water and sufficiently stirred to obtain a mixed solution.

Ammonium hydrogen carbonate [NH ₄ HCO ₃ ] 2
61 g was previously dissolved in 0.5 L of pure water in an autoclave, and the above mixed solution was charged with stirring.
After charging the whole amount of the mixed solution, the autoclave was closed and the temperature was maintained at about 120
At 2 ° C., steam pressure of about 2 kg / cm ² was injected, and when the internal pressure of the autoclave reached 1.1 kg / cm ² , the supply of steam was temporarily stopped. Then, the reaction was performed while adjusting the supply amount of steam so that the internal pressure of the autoclave was maintained at 1.1 kg / cm ² and the maximum condition was 1.2 kg / cm ² . Two hours after the start of the supply of steam, the internal pressure was maintained at 1.1 kg / cm ² even when the supply of steam was stopped. After continuing the reaction for 0.5 hour in this state, the stirring was stopped and the sealing was released.

The slurry-like hydrate after the reaction is removed from the autoclave, and the precipitate is collected by suction filtration.
The precipitate was washed with pure water and dried in an oven at 120 ° C. for 12 hours. Thereafter, the dried powder was calcined in an air at 500 ° C. for 5 hours using an alumina crucible to obtain an electrode material of the present example, which is a perovskite-type composite oxide powder having a catalytic action. Theoretical composition of the electrode material was ^{La 0.9 Gd 0.1 Al 0.95 Pd 0.05} MgO 3. The composition is shown in Table 1.

Next, 100 g of the electrode material of the present example and 8% by weight
100 g of hydrochloric acid acidic alumina sol (a mixed solution of 13 g of boehmite alumina and 87 g of 10 wt% hydrochloric acid aqueous solution) was pulverized and mixed for 5 hours using a planetary ball mill (pots and balls are made of agate), and a perovskite-type composite oxide fine powder slurry was prepared. I got 6.8 g of the obtained slurry,
An oxide was uniformly applied as an oxide on a 15 cm square solid electrolyte substrate, dried at 50 ° C. for 12 hours, and then sintered at 1200 ° C. in air to obtain an air electrode A of this example. The amount of Pd used per air electrode A was 137.4 mg, and was 0.61 mg / cm ² per unit area. Table 2 shows the composition of the cathode
Shown in

Example 2 La 0.8 mol, Gd 0.2
The same operation as in Example 1 was repeated except that the moles, that is, 346.3 g of lanthanum nitrate and 90.3 g of gadolinium nitrate, were used, and the perovskite-type composite oxide La _0.8 Gd _0.2 Al _0.95 Pd _0.05 MgO which was the electrode material of this example Got _three .
Further, the same operation as in Example 1 was further repeated using the obtained electrode material to obtain the air electrode B of this example. This air pole B
The amount of Pd used per sheet was 136.3 mg, and the amount per unit area was 0.606 mg / cm ² .

(Example 3) La 0.7 mol, Gd 0.3
Mol: 303 g of lanthanum nitrate, 1 gadolinium nitrate
Except that the 35.4g, repeat the same operation as in Example 1 to obtain a perovskite-type composite oxide _{La 0.7 Gd 0.3 Al 0.95 Pd 0.05} MgO 3 is an electrode material of the present embodiment. Next, the same operation as in Example 1 was further repeated using this electrode material to obtain the air electrode C of this example. The amount of Pd used per sheet of air C was 135.3 mg, and was 0.601 mg / cm ² per unit area.

Example 4 La 0.6 mol, Gd 0.4
The same operation as in Example 1 was repeated except that the moles, ie, 259.7 g of lanthanum nitrate and 180.5 g of gadolinium nitrate, were used, and the electrode material of the present example was La _0.6 Gd _0.4 Al _0.95 Pd.
_0.05 MgO ₃ was obtained. Next, the same operation as in Example 1 was further repeated using this electrode material to obtain an air electrode D of this example. The amount of Pd used per one air electrode D is 134.
3 mg, and 0.60 mg / c per unit area.
m ² .

Example 5 La 0.5 mol, Gd 0.5
The same operation as in Example 1 was repeated except that the moles, that is, 216.5 g of lanthanum nitrate and 225.7 g of gadolinium nitrate, were used, and the electrode material of this example was La _0.5 Gd _0.5 Al _0.95 Pd.
_0.05 MgO ₃ was obtained. Further, the same operation as in Example 1 was repeated using this electrode material to obtain an air electrode E of this example.
The amount of Pd used per air electrode E is 133.3 mg.
And it was 0.59 mg / cm ² per unit area.

Example 6 0.9 mol of Al, 0.1 Pd
The same operation as in Example 2 was repeated except that the moles, ie, 337.6 g of aluminum nitrate and 23 g + 23 g of [palladium nitrate + H ₂ O], were used, and the electrode material La _0.8 G of this example was used.
to obtain a _{d 0.2 Al 0.9 Pd 0.1 MgO 3} . Further, the same operation as in Example 1 was repeated using this electrode material to obtain the air electrode F of this example. The used amount of Pd per one air electrode F is 268.3 mg, and 1.19 per unit area.
mg / cm ² .

(Example 7) 0.85 mol of Al, Pd.
The same operation as in Example 2 was repeated except that 15 mol, that is, 318.9 g of aluminum nitrate and 34.6 g + 34.6 g of [palladium nitrate + H ₂ O], and the electrode material of this example was La _0.8 Gd _0.2 Al _0.85 Pd _0.15. MgO ₃ was obtained. Further, the same operation as in Example 1 was repeated using this electrode material to obtain the air electrode G of this example. The amount of Pd used per air electrode G was 396.2 mg, and was 1.76 mg / cm ² per unit area.

Example 8 0.8 mol of Al, 0.2 Pd
The same operation as in Example 2 was repeated except that the moles, ie, 300.1 g of aluminum nitrate and 46.1 g + 46.1 g of [palladium nitrate + H ₂ O], were used, and the electrode material of this example was La _0.8 Gd _0.2 Al _0.8 Pd _0.2 MgO. Got _three . Furthermore,
The same operation as in Example 1 was repeated using this electrode material to obtain the air electrode H of this example. The amount of Pd used per air electrode H was 520.15 mg, and was 2.3 mg / cm ² per unit area.

Example 9 0.975 mol of Al, Pt
0.025 mol, ie 365.75 aluminum nitrate
g, dinitrodiaminoplatinum nitrate solution (Pt = 200 g /
(kg solution) 24.5 g + 24.5 g of H ₂ O, and the same operation as in Example 2 was repeated to obtain an electrode material La _0.8 Gd _0.2 Al _0.975 Pt _0.025 MgO ₃ of this example. Further, the same operation as in Example 1 was repeated using this electrode material to obtain the air electrode I of this example. The amount of Pt used per one air electrode I was 125.4 mg, and was 0.56 mg / cm ² per unit area.

Example 10 0.95 mol of Al, Pt
0.05 mol, i.e. aluminum nitrate 356.4 g, dinitrodiamino platinum nitrate solution 48.8g + H ₂ O48.
The same operation as in Example 2 was repeated except that the amount was 8 g,
Electrode material of this example _{La 0.8 Gd 0.2 Al 0.95 Pt 0} .05 MgO
Got _three . Further, the same operation as in Example 1 was repeated using this electrode material to obtain an air electrode J of this example. The amount of Pt used per air electrode J was 245.4 mg, and was 1.09 mg / cm ² per unit area.

Example 11 0.925 mol of Al, Pt
0.075 mole, i.e. aluminum nitrate 347 g, dinitrodiamino platinum nitrate solution 73.0g + H ₂ O73.0
g, the same operation as in Example 2 was repeated, and the electrode material of this example La _0.8 Gd _0.2 Al _0.925 Pt _0.075 MgO
Got _three . Further, the same operation as in Example 1 was repeated using this electrode material to obtain the air electrode K of this example. The amount of Pt used per air electrode K was 362.1 mg, and was 1.61 mg / cm ² per unit area.

(Example 12) Al 0.9 mol, Pt0.
The same operation as in Example 2 was repeated except that 1 mol, that is, 337.6 g of aluminum nitrate and 97.5 g of dinitrodiaminoplatinum nitric acid solution + 97.5 g of H ₂ O, was used, and the electrode material of this example was La _0.8 Gd _0.2 Al _0.9 Pt _0.1 MgO ₃ was obtained. Further, the same operation as in Example 1 was repeated using this electrode material to obtain the air electrode L of this example. The amount of Pt used per one air electrode L was 475 mg, and was 2.11 mg / cm ² per unit area.

Example 13 La 0.9 mol, Dy0.
The nitrates of each metal were mixed at a ratio of 1 mol, 0.95 mol of Al, and 0.05 mol of Pd. That is, 389.6 g of lanthanum nitrate, dysprosium nitrate [Dy (N
_{O 3) 3 · 5H 2 O} ] 43.9g, aluminum nitrate 35
6.4 g, [palladium nitrate + H ₂ O] 11.5 g + 1
1.5 g and 256.4 g of magnesium nitrate were mixed with 1 L of pure water and sufficiently stirred, and the same operation as in Example 1 was repeated to obtain an electrode material of this example La _0.9 Dy _0.1 Al _0.95 Pd.
_0.05 MgO ₃ was obtained. Next, the same operation as in Example 1 was repeated using this electrode material to obtain the air electrode M of this example. The amount of Pd used per one cathode M is 137.3.
mg, and 0.61 mg / cm per unit area.
^{Was 2} .

(Example 14) La 0.8 mol, Dy 0.
The same operation as in Example 13 was repeated except that 2 mol, that is, 346.3 g of lanthanum nitrate and 87.7 g of dysprosium nitrate, was used, and the electrode material of this example was La _0.8 Dy _0.2 Al _0.95.
Pd _0.05 MgO ₃ was obtained. Further, the same operation as in Example 1 was repeated using this electrode material to obtain the air electrode N of this example. The amount of Pd used per air electrode N is 135.8.
mg and 0.603 mg / c per unit area.
m ² .

Example 15 0.7 mol of La, Dy0.
The same operation as in Example 13 was repeated except that 3 mol, that is, 313 g of lanthanum nitrate and 131.6 g of dysprosium nitrate were used, and the electrode material of this example La _0.7 Dy _0.3 Al _0.95 P
d _0.05 MgO ₃ was obtained. Further, the same operation as in Example 1 was repeated using this electrode material to obtain an air electrode O of this example. The amount of Pd used per air electrode O is 134.5.
mg and 0.60 mg / cm per unit area.
^{Was 2} .

Example 16 0.6 mol of La, Dy0.
The same operation as in Example 13 was repeated except that 4 mol, that is, 259.7 g of lanthanum nitrate and 175.4 g of dysprosium nitrate were used, and the electrode material La _0.6 Dy _0.4 Al of this example was repeated.
_0.95 Pd _0.05 MgO ₃ was obtained. Further, the same operation as in Example 1 was repeated using this electrode material, and the air electrode P of this example was repeated.
I got The amount of Pd used per air electrode P is 13
3.2 mg, 0.59 mg per unit area
/ Cm ² .

(Example 17) La 0.5 mol, Dy 0.
The same operation as in Example 13 was repeated except that 5 mol, that is, 216.5 g of lanthanum nitrate and 219.3 g of dysprosium nitrate were used, and the electrode material La _0.5 Dy _0.5 Al of this example was repeated.
_0.95 Pd _0.05 MgO ₃ was obtained. Further, the same operation as in Example 1 was repeated using this electrode material, and the air electrode Q of this example was repeated.
I got The amount of Pd used per one cathode Q is 132
mg and 0.59 mg / cm per unit area.
^{Was 2} .

Example 18 0.9 mol of Al, 0.1 mol of Pd.
The same operation as in Example 14 was repeated, except that 1 mol, that is, 337.6 g of aluminum nitrate and 23 g + 23 g of [palladium nitrate + H ₂ O] was used.
_0.8 Dy _0.2 Al _0.9 Pd _0.1 MgO ₃ was obtained. Further, the same operation as in Example 1 was repeated using this electrode material to obtain the air electrode R of this example. The amount of Pd used per one air electrode R is 267.2 mg, and per unit area:
1.19 mg / cm ² .

Example 19 0.85 mol of Al, Pd
0.15 mol, ie 318.9 g of aluminum nitrate,
The same operation as in Example 14 was repeated, except that [palladium nitrate + H ₂ O] was changed to 34.6 g + 34.6 g, to obtain an electrode material La _0.8 Dy _0.2 Al _0.85 Pd _0.15 MgO ₃ of this example. Further, the same operation as in Example 1 was repeated using this electrode material to obtain an air electrode S. The amount of Pd used per air electrode S was 394.6 mg, and was 1.75 mg / cm ² per unit area.

Example 20 0.8 mol of Al, Pd.
The same operation as in Example 14 was repeated except that 2 mol, that is, 300.1 g of aluminum nitrate and 46.1 g + 46.1 g of [palladium nitrate + H ₂ O] were used, and the electrode material of this example La _0.8 Dy _0.2 Al _0.8 Pd _0.2 MgO ₃ was obtained. Further, the same operation as in Example 1 was repeated using this electrode material to obtain the air electrode T of this example. The amount of Pd used per one air electrode T was 518 mg, and was 2.3 mg / cm ² per unit area.

Example 21 0.975 mol of Al, Pt
0.025 mol, ie 365.3 g of aluminum nitrate,
Dinitrodiaminoplatinic nitric acid solution (Pt = 200 g / kg
Solution) + H ₂ O 24.5 g + 24.5 g except that
The same operation as in Example 14 was repeated to obtain the electrode material L of this example.
a _0.8 Dy _0.2 Al _0.975 Pt _0.025 MgO ₃ was obtained. Further, the same operation as in Example 1 was repeated using this electrode material to obtain the air electrode U of this example. The amount of Pt used per air electrode U was 124.9 mg, and was 0.56 mg / cm ² per unit area.

Example 22 0.95 mol of Al, Pt
0.05 mol, that is, 356.4 g of aluminum nitrate, dinitrodiaminoplatinum nitrate solution + 48.8 g of H ₂ O + 4
The same operation as in Example 14 was repeated except that the amount was changed to 8.8 g, and the electrode material of this example was La _0.8 Dy _0.2 Al _0.95 Pt _0.05
MgO ₃ was obtained. Further, using this electrode material,
The same operation as described above was repeated to obtain the air electrode V of this example. The amount of Pt used per air electrode V was 244.4 mg, and was 1.09 mg / cm ² per unit area.

Example 23 0.925 mol of Al, Pt
0.075 mole, i.e. aluminum nitrate 347 g, dinitrodiamino platinum nitrate solution + H ₂ O73.0g + 73.
The same operation as in Example 14 was repeated except that the amount was 0 g, and the electrode material of this example was La _0.8 Dy _0.2 Al _0.925 Pt _0.075.
MgO ₃ was obtained. Further, using this electrode material,
The same operation as described above was repeated to obtain the air electrode W of this example. The amount of Pt used per air electrode W was 360.6 mg, and was 1.60 mg / cm ² per unit area.

Example 24 0.9 mol of Al, 0.1 mol of Pt.
1 mol, that is, 337.6 g of aluminum nitrate, 97.5 g of dinitrodiaminoplatinum nitric acid solution + 97.5 g of H ₂ O + 97.5 g
Except that the repeats in the same manner as in Example 14, to obtain an electrode material _{La 0.8 Dy 0.2 Al 0.9 Pt 0.} 1 MgO 3 of the present embodiment. Further, the same operation as in Example 1 was repeated using this electrode material to obtain the air electrode X of this example. This air electrode X1
The amount of Pt used per sheet was 473 mg, and was 2.1 mg / cm ² per unit area.

Example 25 An air electrode Y was obtained by repeating the same operation as in Example 1 except that 100 g of hydrochloric acid acidic silica sol containing 6% by weight of Si was used. This air electrode Y1
The amount of Pd used per sheet was 140.6 mg, and was 0.625 mg / cm ² per unit area.

Comparative Example 1 La 0.8 mol, Gd 0.2
Mol, 1.0 mol of Al, 1.0 mol of Mg, 346.3 g of lanthanum nitrate and 9 gadolinium nitrate.
0.3 g, 375.1 g of aluminum nitrate, and 256.4 g of magnesium nitrate were mixed with 1 L of pure water, and sufficiently stirred to obtain a mixed solution. The same operation as in Example 1 was repeated for this mixed solution to obtain a perovskite-type composite oxide powder. The theoretical composition of this composite oxide powder is La _0.8 G
d _0.2 AlMgO ₃ .

Next, 0.05 mol of Pd, that is, palladium nitrate 1 was added to the obtained perovskite-type composite oxide powder.
A solution obtained by dissolving 1.5 g in 100 ml of pure water was mixed, sufficiently stirred, dried in an oven at 120 ° C. for 3 hours, and baked in air at 500 ° C. for 2 hours to obtain an electrode material of this example. A Pd-supported perovskite-type composite oxide powder was obtained.

100 g of the obtained Pd-supported perovskite-type composite oxide powder and 8% by weight hydrochloric acid acidic alumina sol 10
And 0 g were pulverized and mixed using a planetary ball mill for 5 hours to obtain a Pd-supported perovskite-type composite oxide fine powder slurry. The obtained slurry is uniformly coated with 6.8 g of oxide as an oxide on a 15 cm square solid electrolyte substrate, dried at 50 ° C. for 12 hours, and then sintered in air at 850 ° C. to obtain an air electrode a of this example. . The amount of Pd used per air electrode a is 1
35.6 mg, and 0.602 per unit area.
gm / cm ² .

Comparative Example 2 La 0.8 mol, Dy 0.2
The same operation as in Comparative Example 1 was repeated except that the moles, that is, 346.3 g of lanthanum nitrate and 87.7 g of dysprosium nitrate, were used, and the perovskite-type composite oxide La _0.8 Dy _0.2
AlMgO ₃ was obtained. Further, the same operation as in Comparative Example 1 was repeated to obtain a Pd-supported perovskite-type composite oxide powder as the electrode material of this example. Next, the same operation as in Comparative Example 1 was repeated using this electrode material to obtain an air electrode b.
The amount of Pd used per air electrode b was 135 mg, and was 0.60 mg / cm ² per unit area.

[0058] (Comparative Example 3) using a perovskite-type composite oxide La _0.8 Gd _0.2 AlMgO ₃ powder obtained in Comparative Example 1 was slurried by coating the solid electrolyte substrate and sintered, air in this example The pole c was obtained. The air electrode c contains neither Pt nor Pd.

[0059]

[Table 1]

[0060]

[Table 2]

(Characteristic evaluation) Examples 1 to 24 and Comparative Example 1
The measurement cell shown in FIG. 1 was assembled using the air electrode using the electrode material as the perovskite-type composite oxide obtained in Nos. 3 to 3, and the electromotive force was measured. In this measurement, the electromotive force of the noble metal element-containing type oxide according to the present invention and that of the conventional perovskite type composite oxide were Ner
The temperature that coincides with the theoretical electromotive force according to the unst equation was defined as the operation start temperature T _Ne (° C.), and this T _Ne (° C.) was used as an index for characteristic evaluation. In the characteristic evaluation, in FIG.
m of oxygen was flowed, and the electromotive force was measured when 10% O ₂ -N ₂ gas was flowed through the measurement electrode. The evaluation results are also shown in Table 1.

(Evaluation of characteristics after durability) Examples 2, 6, 10,
The air electrodes B, F, J, N, R, V, and a and b obtained in Examples 14, 18, and 22 and Comparative Examples 1 and 2 were durable in an air atmosphere at 1200 ° C. for 5 hours, and the electromotive force was the same as described above. Was measured, and the change in the operation start temperature was determined. Table 3 shows the obtained results.

[0063]

[Table 3]

As shown in Table 3, in Comparative Examples 1 and 2 in which Pd was supported on the composite oxide, Pd crystal particles grew due to heat (durability). Although it operates at a low temperature, it can be seen that it is significantly deteriorated as compared with the air electrode in each embodiment in which Pd or the like is incorporated in the crystal structure.

[0065]

As described above, according to the present invention, a perovskite-type composite oxide represented by the general formula ABCO ₃ is constituted by using a specific metal element such as Mg doping. A perovskite-type composite oxide capable of suppressing solid-phase reaction at the interface with the solid electrolyte, improving heat resistance and durability while maintaining good catalytic action, and realizing power generation in a low temperature range, a method for producing the same, and a method for producing the same And a solid oxide electrolyte fuel cell using the same and an electrode thereof. For this reason, the necessity of using a high heat-resistant material for stacking, which was considered in the conventional high temperature operation type solid electrolyte fuel cell, is eliminated, and the cost can be reduced by using an inexpensive material. Can be put to practical use early, and the effects of using alternative fuels and protecting the environment can be expected.

[Brief description of the drawings]

FIG. 1 is a schematic view showing a measurement cell for evaluating characteristics.

Claims (12)

[Claims] 1. The following general formula (1): A ′ _1-x A ″ _x B ′ _1-y B ″ _y CO ₃ (1) (where A ′ is a lanthanoid element and A ″ is A Lanthanoid elements other than ', B' is an aluminum group element, B "is a platinum group element, C is an alkaline earth metal element, and x is 0 <
x <1, y indicates a number satisfying 0 <y <1. A perovskite-type composite oxide characterized by the following formula: 2. In the formula (1), A ′ is La, A ″
Is Gd and / or Dy, B 'is Al, B "is Pt and / or
2. The perovskite-type composite oxide according to claim 1, wherein Pd and C are Mg. 3. In the formula (1), x is 0 <x ≦ 0.
5. The perovskite-type composite oxide according to claim 1, wherein y satisfies 0 <y ≦ 0.2. 4. An electrode material used for an electrode of a solid oxide electrolyte fuel cell, wherein the material is an electrode material.
An electrode material comprising the perovskite-type composite oxide described in any one of the above items. 5. An electrocatalyst used for an electrode of a solid oxide electrolyte fuel cell, wherein the electrocatalyst is an electrode catalyst.
An electrocatalyst comprising the perovskite-type composite oxide described in any one of the above items. 6. An electrode for use in a solid oxide electrolyte fuel cell, comprising an electrode catalyst according to claim 5 supported thereon. 7. A solid oxide electrolyte fuel cell comprising an air electrode containing the electrode material according to claim 4. 8. A solid oxide electrolyte fuel cell comprising the electrode according to claim 6 as an air electrode. 9. In producing the perovskite-type composite oxide according to any one of claims 1 to 3, the metal element constituting the perovskite-type composite oxide represented by the above formula (1) is selected from the group consisting of: A method for producing a perovskite-type composite oxide, which comprises subjecting a nitrate or a carbonate to a hydrothermal reaction to obtain a monooxycarbonate, and calcining the obtained monooxycarbonate in the air. 10. In producing an electrode for a solid oxide electrolyte fuel cell comprising the electrode material according to claim 4, the electrode material is preliminarily calcined in air to obtain a temporarily sintered powder. Is applied to a solid electrolyte substrate, and then fired in air to produce a fuel cell electrode. 11. The solid electrolyte substrate according to claim 10, wherein the application to the solid electrolyte substrate is performed by applying a slurry obtained by kneading the electrode material with alumina sol or silica sol to the solid electrolyte substrate. A method for manufacturing a fuel cell electrode. 12. The alumina sol or silica sol is acidic with hydrochloric acid and the concentration of alumina or silica is 10% by weight.
The method for manufacturing a fuel cell according to claim 11, wherein: