JP2000334304A - Catalyst for selective oxidation of CO in gas and method for selective oxidation of CO in gas - Google Patents

Abstract

(57) Abstract: A CO oxidation catalyst for selectively oxidizing CO in combustion exhaust gas and hydrogen gas and a method for selectively oxidizing CO in those gases are provided. SOLUTION: (1) La-based perovskite oxide: L
a _{1 over} X Sr _X Mn _{1 over Y} Co Y O ₃ (where x = 0 to 1.0, y
= 0 to 1.0), (2) ZnMn ₂ O ₄ , ZnCo
A spinel oxide selected from ₂ O ₄ or ZnFe ₂ O ₄ ,
Or (3) MgO, CaO, HfO ₂ , Ta ₂ O ₅ , M
nO ₂ , Fe ₂ O ₃ , Co ₃ O ₄ , Rh ₂ O ₃ , CuO, Ce
A CO selective oxidation catalyst in a gas containing CO consisting of an oxide selected from O ₂ , Y ₂ O ₃ and La ₂ O ₃ , and CO
A method for the selective oxidation of CO in gas containing:

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a catalyst for selectively oxidizing CO in a gas containing carbon monoxide (CO), such as flue gas or hydrogen gas, and a method for selectively oxidizing CO in such a gas.

[0002]

2. Description of the Related Art For example, in a gas engine using city gas, natural gas, LP gas or the like, in order to increase combustion efficiency or heat efficiency and to reduce NOx, CO and HC (methane and other hydrocarbons) in exhaust gas. , The ratio of fuel gas to air during combustion is determined by the fuel gas lean
On the n) side, that is, a method in which the supply air amount is made larger than the theoretical air amount necessary for completely burning the fuel gas is applied.

[0003] The gas discharged from the lean burn gas engine contains CO, which is to be touched by humans. Therefore, the CO therein must be sufficiently removed. But,
This exhaust gas contains a large amount of oxygen corresponding to the amount of excess air and water vapor generated as a result of combustion. Therefore, in order to oxidize CO therein and emit it as harmless, it is necessary to include these. It is necessary to develop a purification method that can be applied effectively.

As a catalyst capable of simultaneously removing NOx, CO and HC, there is a three-way catalyst (for example, a catalyst having Pt or Rh supported on alumina), but this catalyst contains almost no oxygen in the exhaust gas to be treated. Moreover, the processing temperature is about 500 ~
It is assumed that the process is performed under the condition of 700 ° C. Therefore, it cannot be applied to CO oxidation treatment in a gas containing a large amount of oxygen and water vapor, such as exhaust gas from a lean burn gas engine.

[0005] As one of the industrial methods for producing hydrogen, there is a steam reforming method for hydrocarbon gas, which is a kind of gas fuel conversion method. In the steam reforming method, a reformer is used, and a hydrocarbon gas is converted into a reformed gas by a catalytic reaction using an appropriate catalyst such as a Ni-based or Ru-based catalyst. The reforming reaction when the hydrocarbon gas is mainly composed of CH ₄ is represented by the following reaction formula (1). However, in this reaction, in addition to unreacted steam and CO ₂ , some CO
The gas is contained as a by-product, and thus the reformed gas is subjected to a CO converter to convert the by-product CO gas into CO ₂ and remove it.

[0006]

Embedded image

The reaction (shift reaction) in the converter is represented by the following equation (2). As the H ₂ O required for this reaction, residual steam that has not been reacted in the reformer is used. CO
The gas leaving the converter is hydrogen (H ₂ ) except for excess water vapor
And carbon dioxide (CO ₂ ), and this hydrogen (H ₂ ) is the target gas component. However, since there is no effective catalyst for the reformed gas obtained through the shift converter,
CO is not completely removed, but contains a small amount of CO.

[0008]

Embedded image

[0009] Hydrogen gas is also used, for example, as fuel for fuel cells. As an example, CO in hydrogen gas used for PAFC (phosphoric acid fuel cell) is about 1%, and for PEFC (solid polymer fuel cell), the limit is about 100 ppm. I do. Therefore, it is necessary to remove the CO component before introducing it into the fuel cell. The hydrogen for adding hydrogen to the unsaturated bond or the hydrogen for oxyhydrogen is usually used in a cylinder, and its purity is required to be 5N or more.

Among the methods for purifying hydrogen, a method of using a catalyst includes a method of oxidizing and removing using a catalyst such as a platinum-based catalyst (JP-A-3-208801, JP-A-10-302821).
No., JP-A-3-93602, and JP-A-10-176177). Also, ultrafine gold (JP-A-63-252908) has been proposed as a CO oxidation catalyst.

However, it is oxidized and removed using a platinum-based catalyst or the like.
In this method, hydrogen is also oxidized and removed at the same time. FIG.
Supports Pt, Pd, and Rh on alumina, respectively.
Catalyst (Pt / Al_TwoO_Three, Pd / Al_TwoO_Three, Rh / A
l_TwoO_ThreeGas containing CO, hydrogen and oxygen using a catalyst)
(CO = 1%, H_Two= 1%, O_Two= 21%, balance = N
_TwoFIG. 9 is a diagram showing the results of an experiment performed for (). here
In this case, the apparatus shown in FIG.
It is calculated from the following. As shown in FIG. 1, these catalysts
Instead of oxidizing only CO, H_TwoIs also oxidized
U.

In the method of removing by a methanation reaction, this reaction is a reaction between CO and H ₂ (CO + 3
Since H ₂ → CH ₄ ), hydrogen does not proceed in an oxidizing atmosphere and also consumes hydrogen. Furthermore, ultrafine gold as a CO oxidation catalyst proposed in Japanese Patent Application Laid-Open No. 63-252908 has excellent properties, but gold is required to be ultrafine and is not easily manufactured.

[0013]

SUMMARY OF THE INVENTION Accordingly, the present invention has been made in order to solve the above-mentioned drawbacks in the prior art, and provides a CO oxidation catalyst capable of selectively oxidizing CO in combustion exhaust gas and hydrogen gas. Another object of the present invention is to provide a method for selectively oxidizing and removing CO in combustion exhaust gas and hydrogen gas.

[0014]

The present invention provides (1) La-based perovskite oxide: La
_-1-X Sr _X Mn _{1 over Y} Co Y O ₃ (where x = 0~1.0, y = 0
Provides CO selective oxidation catalyst in the gas comprising CO, characterized in that it consists of a is 1.0) and the invention is _{(2) ZnMn 2 O 4,} ZnCo 2 O 4 or ZnFe ₂ O ₄ The present invention provides (3) MgO, CaO, HfO ₂ , Ta ₂ O ₅ , a CO selective oxidation catalyst in a gas containing CO, comprising a spinel oxide selected from the group consisting of:
MnO ₂ , Fe ₂ O ₃ , Co ₃ O ₄ , Rh ₂ O ₃ , CuO, C
Provided is a CO selective oxidation catalyst in a gas containing CO, comprising an oxide selected from eO ₂ , Y ₂ O ₃ and La ₂ O ₃ .

Further, the present invention relates to (4) a method of converting a gas containing CO into a La-based perovskite oxide: La _1−X Sr _X Mn _1−Y
Co _Y O ₃ provides selective oxidation method (wherein x = 0 to 1.0, a y = 0 to 1.0) gas, characterized in that through the CO oxidation catalyst comprising CO, In addition, the present invention provides (5) a method of using a gas containing CO as ZnMn ₂ O ₄ , ZnCo ₂ O ₄ ,
Provides ZnFe ₂ O _4, MnCo ₂ O ₄ and CuCr selective oxidation method ₂ O ₄ consisting chosen spinel oxides from the CO gas, characterized in that through the oxidation catalyst CO,
The present invention also provides (6) a gas containing CO as MgO, CaO,
HfO ₂ , Ta ₂ O ₅ , MnO ₂ , Fe ₂ O ₃ , Co ₃ O ₄ , R
h ₂ O _3, CuO, provides selective oxidation method CeO _2, Y ₂ O ₃ and gas, characterized in that through the CO oxidation catalyst comprising an oxide selected from La ₂ O ₃ CO.

[0016]

BEST MODE FOR CARRYING OUT THE INVENTION The CO oxidation catalyst of the present invention comprises (A)
La perovskite oxide: La _{1 over} X Sr _X Mn _1-Y
Co _Y O ₃ catalyst comprising (wherein x = 0 to 1.0, a y = 0~1.0), (B) ZnMn 2 O 4, ZnCo 2 O 4
Or a catalyst comprising a spinel oxide selected from ZnFe ₂ O ₄ and (C) MgO, CaO, HfO ₂ , Ta ₂
O ₅ , MnO ₂ , Fe ₂ O ₃ , Co ₃ O ₄ , Rh ₂ O ₃ , Cu
The catalyst comprises an oxide of any one of O, CeO ₂ , Y ₂ O ₃ and La ₂ O ₃ .

According to the present invention, CO in the gas can be selectively oxidized and removed by these CO oxidation catalysts. Since these are oxides, they are easily available and can be easily manufactured, which is very advantageous in practical use. These oxides can be produced in the same manner as when producing various oxides. Raw materials containing the elements or element sources required for these oxides are uniformly mixed as powders and the like, and are obtained by firing.

When producing La-based perovskite-type oxides and spinel-type oxides, each component element, an oxide of each component element, or a raw material that becomes an oxide upon firing is used. For example, the following raw materials can be used as these raw materials. As the La source, for example, a metal (L
a), oxide (La ₂ O ₃ ), hydroxide [La (O
H) ₃ ], oxyacid salt [La ₂ (CO ₃ ) ₃ ], halide (LaCl ₃ , LaI ₃ etc.), organic acid salt [La (CH ₃ C)
O ₂ ) ₃ ] and the like are used.

As the Sr source, for example, metal (Sr), oxide (SrO), hydroxide [Sr (OH) ₂ etc.], oxyacid salt (SrCO ₃ , SrSO ₄ etc.), halide (SrO ₄ )
Cl _2, etc.), sulfides (SrS or the like), organic acid salt [Sr (C
H ₃ CO ₂ ) ₂ .H ₂ O etc. are used. As the Co source, for example, metal (Co), oxide (CoO, Co ₃ O)
₄ ), oxyacid salts (such as CoCO ₃ ), organic acid salts [Co (C
H ₃ CO ₂ ) ₂ ], halides (CoCl ₂ , CoI ₂
Etc.) are used.

Examples of the Mn source include metals (Mn), oxides (MnO, MnO ₂ , Mn ₂ O _3, etc.), hydroxides [M
_{n (OH) 2, MnO 2} · xH 2 O and the like], a halide (MnF _3, MnCl _3, etc.), sulfides (MnS, MoS ₂
Etc.), oxyacid salt _{[MnCO 3, Mn (NO 3)} 2 · 3H
_{2 O, Mn (NO 3)} 2 · 6H 2 O , etc.] or the like is used. Z
As the n source, for example, metal (Zn), oxide (ZnO)
Etc.), hydroxides [Zn (OH) ₂ etc.], halides (ZnF ₂ , ZnCl ₂ etc.), oxyacid salts [ZnCO ₃ , M
n (NO ₃ ) ₂ etc.].

Examples of the Fe source include metals (Fe), oxides (FeO, Fe ₂ O _3, etc.), hydroxides [Fe (OH)
₂ , Fe (OH) ₃ etc.], halides (FeCl ₂ , F
eCl ₃ , FeBr ₂ etc.), oxyacid salts [FeCO ₃ , Fe
(NO ₃ ) ₂ Fe (NO ₃ ) ₃ etc.]. As the Cr source, for example, metal (Cr), oxide (Cr ₂ O ₃ , C
rO ₃ ), chromic acid (H ₂ CrO ₄ ), dichromic acid (H
₂ Cr ₂ O ₇ ) or their salts and halides (CrCl
₃ etc.) are used. Examples of the Cu source include metals (Cu), oxides (Cu ₂ O, CuO, etc.), hydroxides (Cu (OH) _2, etc.), oxyacid salts (Cu ₂ CO ₃ , CuS
O _4, etc.), halides (CuCl _2, CuCl, CuI
Etc.), sulfides (Cu ₂ S, CuS, etc.), organic acid salts [Cu
(CH ₃ CO ₂ ) ₂ .H ₂ O etc.].

The gas to be treated in the present invention is (1) an exhaust gas containing oxygen and containing CO, and (2) a hydrogen gas containing oxygen and containing CO. Examples of the gas of (1) include combustion gases discharged from various combustion furnaces, various engines, gas fan heaters and the like.
Examples of the gas of (2) include water electrolysis, coal and coke gasification, liquid fuel gasification, gaseous fuel conversion (steam reforming of hydrocarbon gas, etc.), coke oven gas liquefaction separation, Examples of the gas include hydrogen-based gas obtained by various methods such as decomposition of methanol and ammonia. Some of these gases contain no or small amounts of oxygen. In this case, oxygen or air is added as necessary. Further, since the CO selective oxidation catalyst of the present invention has a temperature range effective as a CO selective oxidation catalyst for each type of oxide, it can be appropriately selected and used according to the temperature of the gas to be treated.

[0023]

EXAMPLES Hereinafter, the present invention will be described in more detail with reference to Examples, but it goes without saying that the present invention is not limited to these Examples. The apparatus used in the oxidation activity test was the apparatus shown in FIG.

<< Production Example 1: La-based perovskite-type oxidation
Object, substitution type La_1-XSr_XMn_1-YCo_YO_ThreeOxide tone
Made> Composition LaCoO_Three, LaCrO_Three, LaFeO_Three, L
aMnO_Three, La_0.7Sr_0.3MnO_ThreeAnd La_0.7Sr_0.3
Mn_0.6Co_0.4O_ThreeEach sample is manufactured as follows.
Was. The powder of each raw material shown in Table 1 was used as a raw material.
Each of the powders is weighed to have the above-mentioned composition, and mixed uniformly.
I combined. 400 kgf / cm of the obtained mixed powder ^TwoPressure
Press molding with force, pelletizing, calcining, pulverizing,
After pelletizing under the same conditions as above, the alumina crucible
Each sample was obtained by firing. These preparation conditions are shown in Table 1.
Is shown in

[0025]

[Table 1]

<< Oxidation Activity Test 1 >> The CO oxidation activity and the H ₂ oxidation activity of each sample of the La-based perovskite oxide obtained in Production Example 1 were measured. CO =
Using 1%, H ₂ = 1%, O ₂ = 21%, and N ₂ = balance (volume%, the same applies hereinafter), the test was performed at each temperature in the range of 100 ° C. to 600 ° C. FIG. 3 shows the result. Note that CO
The conversion rate (= CO oxidation rate; conversion)
In the gas to be treated, the CO concentration before the treatment is X and the CO concentration after the treatment is Y, which is calculated by the following equation (1). In this regard, the H ₂ conversion rate (= H ₂ oxidation rate; conversion)
Was similarly calculated.

[0027]

(Equation 1)

As shown in FIG. 3, it is clear that each sample selectively oxidizes CO. For example, LaCoO ₃
In the case of, CO starts to be oxidized from about 150 ° C.
At 85 ° C., about 85%, and at 300 ° C., 100%, that is, CO is completely oxidized. On the other hand, the oxidation activity with respect to H ₂ shifts to a higher temperature side, and is about 48% at 300 ° C. and about 82% at 400 ° C. Thus LaCo
The CO selective oxidation activity of O ₃ is clear. LaFeO ₃ ,
LaCrO ₃ and LaMnO ₃ also show a higher CO selective oxidation activity in these cases, although at higher temperatures.

<< Oxidation activity test 2 >> FIG.
For the sample of MnO _3, the gas to be treated containing CH ₄ : CO
= 1%, H ₂ = 1%, CH ₄ = 1%, O ₂ = 21%, N ₂ =
The results are obtained by performing the reaction at a temperature in the range of 100 ° C. to 600 ° C. using the balance. As shown in FIG.
Is effectively oxidized, compared to the oxidizing activity of H ₂ , at 250 ° C.
Thereafter, it shows an effective selective oxidizing property, and shows an excellent selective oxidizing property from 250 ° C. to over 500 ° C. as compared with the oxidizing activity of CH ₄ .

<< Oxidation activity test 3 >> The substituted La _1-X S
r _X Mn _{1 over} Y Co _Y O ₃ oxides: For each sample of La _0.7 Sr _0.3 MnO ₃ and _{La 0.7 Sr 0.3 Mn 0.6 Co 0.4} O 3 was measured CO oxidation activity and hydrogen oxidation activity. The conditions such as the gas to be treated and the reaction temperature are the same as in the oxidation activity test 1.
FIG. 5 shows the results, and also shows the results for LaMnO ₃ and LaCoO ₃ . La _0.7 Sr _0.3 Mn _0.6 C
For o _0.4 O _3, shows a substantially similar selective oxidation activity as LaCoO _3, are further improved compared to LaCoO _3.

That is, for example, at 200 ° C., CO 2
The oxidation activity, whereas it is about 84% when the LaCoO _3, a _{La 0.7 Sr 0.3 Mn 0.6 Co 0.4} O 3 in about 91%, for H ₂ oxidation activity, LaC
In the case of oO ₃ , it is about 18%, whereas La _0.7 Sr
_{In the case of 0.3} Mn _0.6 Co _0.4 O ₃ , the content is about 9%, indicating a more improved selective oxidation of CO. In this regard, La _0.7 S
Although r _0.3 MnO ₃ is on the higher temperature side, it exhibits the same CO selective oxidation activity.

Table 2 shows that in the above-mentioned oxidation activity test 3, H
₍₂₎ Maximum oxidation rate of CO with respect to oxidation rate, that is, CO selective oxidation rate [Tsel / ° C (reaction temperature at which maximum selectivity was shown)
Difference in CO oxidation rate and H ₂ oxidation ratio in; CO sele
activity /%]. LaMnO
₃ is 57.0% at 600 ° C, LaCoO ₃ is 200 ° C
Indicates a CO selective oxidation rate of 68.8%. La _0.7
Sr _0.3 MnO ₃ and La _0.7 Sr _0.3 Mn _0.6 Co _0.4 O ₃
In the case of La _0.7 Sr _0.3 MnO ₃ , it is even higher.
84.4% at 0 ° C., La _0.7 Sr _0.3 Mn _0.6 Co _0.4 O ₃
Shows a CO selective oxidation rate of 83.9% at 200 ° C.

[0033]

[Table 2]

<< Production Example 2: Preparation of Spinel-Type Oxide >> Composition ZnMn ₂ O ₄ , ZnCo ₂ O ₄ , ZnFe ₂ O ₄ , CuC
Each sample of r ₂ O ₄ was produced in the same manner as in Production Example 1. Table 3
Shows raw materials used and preparation conditions. Of these samples, samples other than CuCr ₂ O ₄ were subjected to main firing without undergoing calcination.

[0035]

[Table 3]

<< Oxidation Activity Test 4 >> ZnMn ₂ O ₄ , ZnC
o ₂ O _4, ZnFe about ₂ O _4, each sample of _{MnCo 2 O 4, CuCr 2 O} 4 was measured CO oxidation activity and hydrogen oxidation activity. The conditions of the gas to be treated and the reaction temperature are as follows:
Is the same as FIG. 6 shows the result. As shown in FIG. 6, it is clear that each sample selectively oxidizes CO.
For example, in the case of ZnCo ₂ O ₄ , CO begins to be oxidized at about 120 ° C., and about 59% at 200 ° C. and 10% at 250 ° C.
0%, that is, CO is completely oxidized. On the other hand, the oxidizing activity for H ₂ shifts to a higher temperature side and 2
It is about 5% even at 00 ° C. and about 20% even at 250 ° C.
Thus, the CO selective oxidation activity of ZnCo ₂ O ₄ is apparent. ZnMn ₂ O ₄ , MnFe ₂ O ₄ , MnCo ₂ O ₄ , C
The temperature of uCr ₂ O ₄ is also higher, but the same C
It shows O selective oxidation activity.

Table 4 shows that in the above oxidation activity test 4, H
_This shows the maximum oxidation rate of CO with respect to the oxidation rate, that is, the selective oxidation rate of CO. 350 ° C. for ZnMn ₂ O ₄
Has a CO selective oxidation rate of just over 20%, but ZnCo ₂ O ₄ ,
ZnFe ₂ O _4, a MnCo ₂ O _4, CuCr the ₂ O ₄ more effective, if the ZnCo ₂ O _4, 79.4 at 250 ° C.
It shows an excellent CO selective oxidation rate of 2%.

[0038]

[Table 4]

<< Oxidation Activity Test 5 >> Oxides: MgO, CaO, HfO ₂ , Ta ₂ O ₅ , Mn
O ₂ , Fe ₂ O ₃ , Co ₃ O ₄ , Rh ₂ O ₃ , CuO, Ce
For each of the 12 kinds of samples of O ₂ , Y ₂ O ₃ and La ₂ O ₃ , CO
The oxidation activity and the hydrogen oxidation activity were measured. These oxide samples are commercially available, and the conditions such as the gas to be treated and the reaction temperature are the same as in the oxidation activity test 1. Table 5 shows the maximum oxidation rate of CO with respect to the H ₂ oxidation rate in the present oxidation activity test 5, that is, the CO selective oxidation rate. Table 5
As comparative examples, Cr ₂ O ₃ , Ga ₂ O ₃ , In ₂ O ₃ , S
The case where four types of nO ₂ samples are used is also described.

[0040]

[Table 5]

As shown in Table 5, each of the above 12 kinds of oxides shows selective CO oxidation. For example, La ₂
O ₃ shows a significant CO selective oxidation rate of 12.7% at 500 ° C., and CuO shows an excellent CO selective oxidation rate of 76.1% at 300 ° C. On the other hand, in Comparative Examples: Cr ₂ O ₃ , Ga ₂ O ₃ , In ₂ O ₃ and SnO ₂ ,
Contrary to the above twelve oxides, H ₂ is selectively oxidized.

[0042]

According to the CO selective oxidation catalyst of the present invention,
CO in combustion exhaust gas and hydrogen gas can be selectively oxidized and removed. Further, since the CO selective oxidation catalyst of the present invention has a temperature range effective as a CO selective oxidation catalyst for each type of oxide, it can be appropriately selected and used according to the temperature of the gas to be treated. Further, since the catalyst of the present invention is an oxide, it is easily available and can be easily produced, which is extremely advantageous in practical use.

[Brief description of the drawings]

FIG. 1 Pt / Al ₂ O ₃ , Pd / Al ₂ O ₃ , Rh / Al
Shows the ₂ O ₃ catalyst of CO and H ₂ oxidation activity.

FIG. 2 is a view showing an apparatus used in oxidation activity tests 1 to 5.

FIG. 3 is a diagram showing the CO and hydrogen oxidation activity of a La-based perovskite oxide.

FIG. 4 is a graph showing the CO oxidation activity, H ₂ and CH ₄ oxidation activity of LaMnO ₃ .

5 is a diagram showing CO and hydrogen oxidation activity of substitutional La _{1 over} X Sr _X Mn _{1 over} Y Co _Y O ₃ oxide.

FIG. 6 is a graph showing CO and hydrogen oxidation activity of a spinel oxide.

Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat II (reference) B01J 23/02 B01J 23/02 M 23/10 A 23/10 M 23/16 A 23/16 M 23/34 A 23 / 34 M 23/46 A 23/46 M C01B 3/40 C01B 3/40 C01G 37/00 C01G 37/00 45/00 45/00 49/00 49/00 51/00 A 51/00 B01D 53/36 CF term (reference) 4D048 AA13 AB01 AC06 BA01X BA02X BA13X BA16X BA18X BA19X BA25X BA28X BA33X BA35X BA36X BA37X BA38X BA41X BA42X BB01 4G002 AA06 AB01 AB07 AE05 4G040 EA01 EB32 EC02 EC03 A08 EA04 AA02 AA08 AA09 AA11 BA06A BA06B BA06C BB04A BB04B BB04C BB05C BB06A BB06B BB06C BB09C BB16C BC09A BC09B BC09C BC10A BC10B BC10C BC12A BC12B BC12C BC31A BC31B BC31C BC35A BC35B BC35C BC40A BC40B BC40C BC42A BC42B BC42C BC43A BC43B BC43C BC52A BC52B BC52C BC56A BC56B BC56C BC58A BC58B BC58C BC62A BC62B BC62C BC66A BC66B BC66C BC67A BC67B BC67C BC68A BC68B BC68C BC71A BC71B BC71C CA 02 CA03 CA07 CA14 DA05 EA02Y FA01 FB07 FB33 FC02

Claims (8)

[Claims] 1. La perovskite oxide: La _1-X
Sr _X Mn _{1 over Y} Co Y O ₃ (where x = 0~1.0, y = 0~
1.0.) A catalyst for selective oxidation of CO in a gas containing CO. 2. ZnMn ₂ O ₄ , ZnCo ₂ O ₄ , ZnFe ₂
O _4, MnCo ₂ O ₄ and CuCr CO selective oxidation catalyst in the gas comprising CO, characterized in that it consists of spinel type oxide selected from ₂ O _4. 3. MgO, CaO, HfO_Two, Ta_TwoO_Five, Mn
O_Two, Fe_TwoO_Three, Co_ThreeO_Four, Rh_TwoO _Three, CuO, Ce
O_Two, Y_TwoO_ThreeAnd La_TwoO_ThreeConsisting of oxides selected from
CO selective oxidation catalyst in CO containing gas characterized by the following:
Medium. 4. The catalyst for selective oxidation of CO in a gas containing CO according to claim 1, wherein the gas containing CO is a combustion exhaust gas or a hydrogen gas. 5. A method according to claim 5, wherein the gas containing CO is a La-based perovskite oxide: La _1−X Sr _X Mn _1−Y Co _{YO 3} (where x = 0 to 0)
1.0, y = 0 to 1.0). 6. A gas containing CO is ZnMn ₂ O ₄ , ZnCo
_{2 O 4, ZnFe 2 O 4} , MnCo 2 O 4 and CuCr ₂ O ₄ from the chosen selective oxidation method in the gas CO, characterized in that through the CO oxidation catalyst comprising a spinel-type oxides. 7. A gas containing CO is MgO, CaO, HfO.
₂ , Ta ₂ O ₅ , MnO ₂ , Fe ₂ O ₃ , Co ₃ O ₄ , Rh
_A method for selectively oxidizing CO in a gas, comprising passing through a CO oxidation catalyst comprising an oxide selected from ₂ O ₃ , CuO, CeO ₂ , Y ₂ O ₃ and La ₂ O ₃ . 8. The C in gas according to claim 5, wherein the gas containing CO is a combustion exhaust gas or a hydrogen gas.
A method for selective oxidation of O.