KR102108863B1 - Transition metal co-doped cerium oxide and method for preparing the same - Google Patents

Abstract

The present invention relates to a co-doped cerium oxide represented by the following Chemical Formula 1 and a method for manufacturing the same, and the co-doped cerium oxide of the present invention has high activity and is used as a catalyst for carbon monoxide oxidation reaction. It can be used.
[Formula 1]
M ¹ _x M ² _y Ce _{1- (x + y)} O _2-δ
In Chemical Formula 1,
M ¹ and M ² are different from each other, each independently a transition metal,
x is 0 <x≤0.2, y is 0 <y≤0.2, and δ is 0≤δ≤0.4.

Description

Transition metal co-doped cerium oxide and its manufacturing method {TRANSITION METAL CO-DOPED CERIUM OXIDE AND METHOD FOR PREPARING THE SAME}

The present invention relates to a cerium oxide co-doped with a transition metal and a method for manufacturing the same, and more particularly, to a cerium oxide co-doped with a transition metal that has high activity and can be used as a catalyst for a carbon monoxide oxidation reaction. It is about.

Cerium oxide is often used as a support for active materials. The role of the support in the reaction must be stable with the oxygen supply and the active substance. Cerium oxide is well formed on the surface due to its high oxygen storage capacity and redox ability of Ce ^{3 +} / Ce ^{4 +} . In addition, it has high thermal stability and excellent interaction with transition metals, so it has been applied as a support to various reactions and its superiority has been proved.

Automobile exhaust gas in Korea accounts for 85.4% of air pollution and is a serious pollutant. These emissions not only directly affect the human body, but also cause serious problems such as ozone (O ₃ ) production and global warming. In the metropolitan area, 47% of automobiles are concentrated in an area of only 12% of the country, so urban exhaust gas purification technology is essential to Korea. Typical harmful gases among automobile emissions include HC, NO _x , CO, CO ₂ and fine dust. Among them, various techniques are known to treat and decompose carbon monoxide (CO), and among them, the catalytic oxidation method is known as the best method in that it can directly convert contaminants into substances harmless to the human body. However, the prior art using a catalyst requires additional energy, such as thermal energy or light energy, and thus has many restrictions on its use. For this reason, recently, studies on catalysts for oxidizing carbon monoxide under room temperature conditions have been conducted, but most have problems of low carbon monoxide conversion and poor durability.

The present invention is to solve the problems of the prior art as described above, the object of the present invention is to provide a high activity, can be used as a catalyst for the oxidation of carbon monoxide transition metal co-doped cerium oxide and to provide a method for producing the same Having

According to an aspect of the present invention, a co-doped cerium oxide represented by Chemical Formula 1 is provided.

[Formula 1]

M ¹ _x M ² _y Ce _{1- (x + y)} O _2-δ

In Chemical Formula 1,

M ¹ and M ² are different from each other, each independently a transition metal,

x is 0 <x≤0.2, y is 0 <y≤0.2, and δ is 0≤δ≤0.4.

In addition, the co-doped cerium oxide is in Formula 1, M ¹ is silver (Ag), ruthenium (Ru), cobalt (Co) or manganese (Mn), M ² is copper (Cu) or iron (Fe).

In addition, the co-doped cerium oxide in Formula 1, M ¹ is silver (Ag), ruthenium (Ru), cobalt (Co) or manganese (Mn), M ² may be copper (Cu) have.

Further, the co-doped cerium oxide may be M ¹ in silver (Ag) or ruthenium (Ru), and M ² in copper (Cu).

In addition, the co-doped cerium oxide may be M ¹ in silver (Ag) and M ² in copper (Cu).

In addition, the co-doped cerium oxide may be for use as a catalyst in the oxidation reaction of carbon monoxide (CO).

In addition, the co-doped cerium oxide may be M ¹ in silver (Ag) and M ² in copper (Cu).

In addition, the carbon monoxide may be included in the combustion exhaust gas.

According to another aspect of the present invention, (a) preparing a precursor aqueous solution containing a cerium precursor and two transition metal precursors; (b) preparing an EDTA aqueous solution containing ethylenediaminetetraacetic acid (EDTA) and ammonia; (c) preparing an aqueous EDTA complex solution containing the complex of the EDTA by mixing and reacting the precursor aqueous solution, the EDTA aqueous solution, and citric acid; (d) drying the EDTA complex aqueous solution; And (e) preparing the co-doped cerium oxide represented by Chemical Formula 1 by sintering the dried product of step (d) by heat treatment; A manufacturing method is provided.

[Formula 1]

M ¹ _x M ² _y Ce _{1- (x + y)} O _2-δ

In Chemical Formula 1,

M ¹ and M ² are different from each other, each independently a transition metal,

x is 0 <x≤0.2, y is 0 <y≤0.2, and δ is 0≤δ≤0.4.

In addition, the cerium precursor may include at least one selected from the group consisting of cerium nitrate hydrate (Ce (NO ₃ ) ₃ ㆍ 6H ₂ O) and cerium chloride hydrate (CeCl ₃ ㆍ 7H ₂ O).

Also, the two transition metal precursors may be a silver precursor and a copper precursor, and the co-doped cerium oxide may be M ¹ in silver (Ag) and M ² in copper (Cu). have.

In addition, the silver precursor may include one or more selected from the group consisting of silver nitrate (AgNO ₃ ), silver chloride (AgCl), and silver perchlorate (AgClO ₄ ).

In addition, the copper precursor contains at least one selected from the group consisting of copper nitrate hydrate (CuN ₂ O ₆ ㆍ 3H ₂ O), copper hydroxide (Cu (OH) ₂ ) and copper chloride hydrate (CuCl ₂ ㆍ 2H ₂ O). can do.

In addition, the step (d ′) of evaporating impurities at 400 to 470 ° C. as a result of the step (d) dried between steps (d) and (e); may further include.

In addition, the sintering in step (e) can be performed at 450 to 700 ° C.

The co-doped cerium oxide of the present invention has a high activity and has an effect that can be used as a catalyst for carbon monoxide oxidation.

Figure 1a shows the results of XRD analysis of the cerium oxide single-doped Cu prepared according to Comparative Example 2.
1B shows Ce ₀ prepared according to Examples 1-6 _{. 90} Ag _{0 . 01} Cu _{0 . 09} O _{2 -δ} and Ce ₀ prepared according to Examples 1-7 _{. 90} Ag _{0 . 02} Cu _{0 . The} results of XRD analysis of ₀₈ O _{2 -δ} are shown.
Figure 1c shows the results of XRD analysis of Ag and Cu co-doped cerium oxide prepared according to Examples 1-1 to 1-5 and Ru and Cu co-doped cerium oxide prepared according to Example 2.
2A shows CeO ₂ prepared according to Comparative Example 1, Ce _0.95 Cu _0.05 O _2-δ prepared according to Comparative Example 2-1, and Ce ₀ prepared according to Example 1-1 _{. 95} Ag _{0 . 01} Cu _{0 . 04} O _{2 -δ} , TEM image of Ce _0.95 Ru _0.01 Cu _0.04 O _2-δ prepared according to Example 2.
2B shows Ce ₀ prepared according to Example 1-1 _{. 95} Ag _{0 . 01} Cu _{0 . This} is a SEM-EDS image of ₀₄ O _{2 -δ} .
3A shows Ce ₀ prepared according to Comparative Example 2-1 _{. 95} Cu _{0 . 05} shows the results of Raman spectrum analysis of O _{2 -δ} .
3B shows Ce ₀ prepared according to Example 1-1 _{. 95} Ag _{0 . 01} Cu _{0 . 04 The} results of Raman spectrum analysis of O _{2 -δ} are shown.
Figure 3c is Ce ₀ prepared according to Example 2 _{. 95} Ru _{0 . 01} Cu _{0 . 04 The} results of Raman spectrum analysis of O _{2 -δ} are shown.
Figure 3d shows the results of Raman spectrum analysis of CeO ₂ prepared according to Comparative Example 1.
4A shows Ce ₀ prepared according to Example 1-1 _{. 95} Ag _{0 . 01} Cu _{0 . The} results of XPS analysis of Ce _0.95 Cu _0.05 O _2-δ prepared according to ₀₄ O _{2 -δ} and Comparative Example 2-1 are shown.
4B shows Ce ₀ prepared according to Example 1-1 _{. 95} Ag _{0 . 01} Cu _{0 . The} results of XPS analysis of Ce _0.95 Cu _0.05 O _2-δ prepared according to ₀₄ O _{2 -δ} and Comparative Example 2-1 are shown.
4C shows Ce ₀ prepared according to Example 1-1 _{. 95} Ag _{0 . 01} Cu _{0 . The} results of XPS analysis of Ce _0.95 Cu _0.05 O _2-δ prepared according to ₀₄ O _{2 -δ} and Comparative Example 2-1 are shown.
4D shows Ce ₀ prepared according to Example 1-1 _{. 95} Ag _{0 . 01} Cu _{0 . The} results of XPS analysis of ₀₄ O _{2 -δ} are shown.
4E is Ce ₀ prepared according to Example 1-1 _{. 95} Ag _{0 . 01} Cu _{0 . The} results of XPS analysis of ₀₄ O _{2 -δ} are shown.
5A shows Ce ₀ prepared according to Example 1-1 _{. 95} Ag _{0 . 01} Cu _{0 . 04} O _{2 -δ} , Ce ₀ prepared according to Example 2 _{. 95} Ru _{0 . 01} Cu _{0 . 04} O _{2 -δ} , CeO ₂ prepared according to Comparative Example 1, Ce _0.95 Cu _0.05 O _2-δ prepared according to Comparative Example 2-1 adsorbed oxygen on the catalyst surface, and then confirmed the desorption capacity of oxygen. It is shown.
5B shows Ce ₀ prepared according to Example 1-1 _{. 95} Ag _{0 . 01} Cu _{0 . 04} O _{2 -δ} , Ce ₀ prepared according to Example 2 _{. 95} Ru _{0 . 01} Cu _{0 . 04} O _{2 -δ} , CeO ₂ prepared according to Comparative Example 1, Ce _0.95 Cu _0.05 O _2-δ prepared according to Comparative Example 2-1 is a graph showing the H ₂ consumption (H ₂ Consumption).
6A shows Ce ₀ prepared according to Example 1-1 _{. 95} Ag _{0 . 01} Cu _{0 . 04} O _{2 -δ} , Ce ₀ prepared according to Comparative Example 1-1 _{. 95} Cu _{0 . 05} O _{2 -δ} , Ce ₀ prepared according to Example 2 _{. 95} Ru _{0 . 01} Cu _{0 . It} is a graph showing the result of CO conversion using ₀₄ O _{2 -δ} .
6B is a graph showing activation energy calculated using FIG. 6A.
6C shows Ce ₀ prepared according to Example 1-1 _{. 95} Ag _{0 . 01} Cu _{0 . 04} O _{2 -δ} , Ce ₀ prepared according to Comparative Example 1-1 _{. 95} Cu _{0 . 05} O _{2 -δ} , Ce ₀ prepared according to Example 2 _{. 95} Ru _{0 . 01} Cu _{0 . It} is a graph showing the catalytic reaction rate according to the temperature of ₀₄ O _{2 -δ} .

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings so that those skilled in the art to which the present invention pertains may easily practice.

However, the following description is not intended to limit the present invention to specific embodiments, and when it is determined that a detailed description of known technologies related to the present invention may obscure the subject matter of the present invention, the detailed description will be omitted. .

The terms used herein are only used to describe specific embodiments, and are not intended to limit the present invention. Singular expressions include plural expressions unless the context clearly indicates otherwise. In this application, terms such as “include” or “have” are intended to indicate that a feature, number, step, operation, component, or combination thereof described in the specification exists, or that one or more other features or It should be understood that the existence or addition possibilities of numbers, steps, actions, elements, or combinations thereof are not excluded in advance.

The present invention provides a co-doped cerium oxide represented by Formula 1 below.

[Formula 1]

M ¹ _x M ² _y Ce _{1- (x + y)} O _2-δ

In Chemical Formula 1

M ¹ and M ² are different from each other, each independently a transition metal,

x is 0 <x≤0.2, y is 0 <y≤0.2, and δ is 0≤δ≤0.4.

In the above Chemical Formula 1, the co-doped cerium oxide is

M ¹ is silver (Ag), ruthenium (Ru), cobalt (Co) or manganese (Mn), preferably silver (Ag) or ruthenium (Ru), more preferably silver (Ag),

M ² may be copper (Cu) or iron (Fe), preferably copper (Cu).

The co-doped cerium oxide may be for use as a catalyst in the oxidation reaction of carbon monoxide (CO).

The carbon monoxide may be included in the combustion exhaust gas.

Hereinafter, a method of manufacturing a co-doped cerium oxide of the present invention will be described.

The present invention (a) preparing a precursor aqueous solution containing a cerium precursor and two types of transition metal precursors; (b) preparing an EDTA aqueous solution containing ethylenediaminetetraacetic acid (EDTA) and ammonia; (c) preparing an aqueous EDTA complex solution containing the complex of the EDTA by mixing and reacting the precursor aqueous solution, the EDTA aqueous solution, and citric acid; (d) drying the EDTA complex aqueous solution; And (e) preparing the co-doped cerium oxide represented by Chemical Formula 1 by sintering the dried product of step (d) by heat treatment; Provide a manufacturing method.

[Formula 1]

M ¹ _x M ² _y Ce _{1- (x + y)} O _2-δ

In Chemical Formula 1

M ¹ and M ² are different from each other, each independently a transition metal,

x is 0 <x≤0.2, y is 0 <y≤0.2, and δ is 0≤δ≤0.4.

First, a precursor aqueous solution containing a cerium precursor and two types of transition metal precursors is prepared (step a).

The cerium precursor may include at least one selected from the group consisting of cerium nitrate hydrate (Ce (NO ₃ ) ₃ ㆍ 6H ₂ O) and cerium chloride hydrate (CeCl ₃ ㆍ 7H ₂ O), preferably cerium nitrate Hydrate (Ce (NO ₃ ) ₃ ㆍ 6H ₂ O).

The two types of transition metal precursors are silver precursors and copper precursors, and the co-doped cerium oxide may be M ¹ in silver (Ag) and M ² in copper (Cu). .

The silver precursor may include one or more selected from the group consisting of silver nitrate (AgNO ₃ ), silver chloride (AgCl), and silver perchlorate (AgClO ₄ ), preferably silver nitrate (AgNO ₃ ).

The copper precursor may include at least one selected from the group consisting of copper nitrate hydrate (CuN ₂ O ₆ ㆍ 3H ₂ O), copper hydroxide (Cu (OH) ₂ ) and copper chloride hydrate (CuCl ₂ ㆍ 2H ₂ O). It may, preferably, include copper nitrate hydrate (CuN ₂ O ₆ ㆍ 3H ₂ O).

to the next, Ethylenediaminetetraacetic acid ( Ethylenediaminetetraacetic  acid, EDTA) and ammonia EDTA  Prepare an aqueous solution (step b).

Next, the aqueous precursor solution, the EDTA  The aqueous solution and citric acid were mixed and reacted to EDTA Complex  Containing EDTA Complex  Prepare an aqueous solution (step c).

Next, above EDTA Complex  Aqueous solution Dry it (Step d).

The step (d ′) of evaporating impurities at 400 to 470 ° C. may be further included.

Finally, the resultant of the dried step (d) is sintered by heat treatment to be represented by Chemical Formula 1 Co-doping (co-doped) cerium oxide is prepared (step e).

The sintering in step (e) can be performed at 450 to 700 ° C.

[Example]

Hereinafter, a preferred embodiment of the present invention will be described. However, this is for illustrative purposes, and the scope of the present invention is not limited thereby.

Example 1: Preparation of cerium oxide co-doped with Ag and Cu

Example  1-1: Ce: Ag: Cu Mole ratio = 0.95: 0.01: 0.04

Ce cerium nitrate hydrate (Ce (NO ₃ ) ₃ ㆍ 6H ₂ O), silver precursor silver nitrate (AgNO ₃ ) and copper precursor copper nitrate hydrate (CuN ₂ O ₆ ㆍ 3H ₂ O) are their metal elements, Ce An aqueous solution was prepared by dissolving in 100 mL of distilled water so that the molar ratio of: Ag: Cu was 0.95: 0.01: 0.04.

An EDTA solution was prepared by mixing EDTA (Ethylenediaminetetraacetic acid) with ammonia water, and then the EDTA solution, the aqueous solution, and 30 mL of citric acid were mixed to prepare a mixed solution. Ammonia was added and titrated so that the mixed solution was at pH 10. In order to maintain the temperature of the mixed solution at 80 ° C, an EDTA complex was prepared by heating on a plate at 158 ° C.

The EDTA complex was heat-treated at 450 ° C in a heating mantle to evaporate impurities, and sintered by heating at 500 ° C for 3 hours in a kiln to prepare Ce _0.95 Ag _0.01 Cu _0.04 O _2-δ , a co-doped cerium oxide. Here, 2-δ is a value determined depending on the type and amount of the metal to be doped. The metal cation and oxygen anion are electrically molar ratios of oxygen anions, and it is difficult to experimentally measure an accurate δ value.

Example  1-2: Ce: Ag: Cu Mole ratio = 0.95: 0.015: 0.035

Ce _0.95 Ag _0.015 Cu _{0.035 in the} same manner as in Example 1-1, except that in Example 1-1, the molar ratio of Ce: Ag: Cu was 0.95: 0.01: 0.04 instead of 0.95: 0.015: 0.035. O _2-δ was prepared.

Example  1-3: Ce: Ag: Cu Mole ratio = 0.95: 0.02: 0.03

Ce _0.95 Ag _0.02 Cu _{0.03 in the} same manner as in Example 1-1, except that the molar ratio of Ce: Ag: Cu in Example 1-1 was 0.95: 0.02: 0.03 instead of 0.95: 0.01: 0.04. O _2-δ was prepared.

Example  1-4: Ce: Ag: Cu Mole ratio = 0.95: 0.025: 0.025

Ce _0.95 Ag _0.025 Cu _{0.025 in the} same manner as in Example 1-1, except that in Example 1-1, the molar ratio of Ce: Ag: Cu was 0.95: 0.01: 0.04 instead of 0.95: 0.025: 0.025. O _2-δ was prepared.

Example  1-5: Ce: Ag: Cu Mole ratio = 0.95: 0.03: 0.02

Ce _0.95 Ag _0.03 Cu _{0.02 in the} same manner as in Example 1-1, except that the molar ratio of Ce: Ag: Cu in Example 1-1 was 0.95: 0.03: 0.02 instead of 0.95: 0.01: 0.04. O _2-δ was prepared.

Example  1-6: Ce: Ag: Cu Mole ratio = 0.90: 0.01: 0.09

Ce _0.90 Ag _0.01 Cu _{0.09 in the} same manner as in Example 1-1, except that the molar ratio of Ce: Ag: Cu in Example 1-1 was 0.90: 0.01: 0.09 instead of 0.95: 0.01: 0.04. O _2-δ was prepared.

Example  1-7: Ce: Ag: Cu Mole ratio = 0.90: 0.02: 0.08

Ce _0.90 Ag _0.02 Cu _{0.08 in the} same manner as in Example 1-1, except that the molar ratio of Ce: Ag: Cu in Example 1-1 was 0.90: 0.02: 0.08 instead of 0.95: 0.01: 0.04. O _2-δ was prepared.

Example  2: Ru  And Cu Co-doped  Cerium oxide ( Ce: Ru: Cu Mole ratio = 0.95: 0.01: 0.04) Preparation

Cerium precursor cerium nitrate hydrate (Ce (NO ₃ ) ₃ ㆍ 6H ₂ O), ruthenium precursor ruthenium chloride hydrate (RuCl ₃ ㆍ xH ₂ O) (x is any integer from 1 to 9) and copper precursor copper An aqueous solution was prepared by dissolving nitrate hydrate (CuN ₂ O ₆ ㆍ 3H ₂ O) in 100 mL of distilled water so that their metal element Ce: Ru: Cu molar ratio was 0.95: 0.01: 0.04.

An EDTA solution was prepared by mixing EDTA (Ethylenediaminetetraacetic acid) with ammonia water, and then the EDTA solution, the aqueous solution, and 30 mL of citric acid were mixed to prepare a mixed solution. Ammonia was added and titrated so that the mixed solution was at pH 10. In order to maintain the temperature of the mixed solution at 80 ° C, an EDTA complex was prepared by heating on a plate at 158 ° C.

The EDTA complex was heat-treated at 450 ° C in a heating mantle to evaporate impurities, and sintered by heating at 500 ° C for 3 hours in a kiln to prepare Ce _0.95 Ru _0.01 Cu _0.04 O _2-δ , a co-doped cerium oxide.

Comparative Example 1: Cerium oxide (CeO ₂ ) Produce

An aqueous solution was prepared by dissolving cerium nitrate hydrate (Ce (NO ₃ ) ₃ ㆍ 6H ₂ O), a cerium precursor, in 100 mL of distilled water so that the molar ratio of Ce, a metal element, was 1.

An EDTA solution was prepared by mixing EDTA (Ethylenediaminetetraacetic acid) with ammonia water, and then the EDTA solution, the aqueous solution, and 30 mL of citric acid were mixed to prepare a mixed solution. Ammonia was added and titrated so that the mixed solution was at pH 10. In order to maintain the temperature of the mixed solution at 80 ° C, an EDTA complex was prepared by heating on a plate at 158 ° C.

The EDTA complex was heat-treated at 450 ° C in a heating mantle to evaporate impurities, and sintered by heating at 500 ° C for 3 hours in a firing box to prepare CeO ₂ as a cerium oxide.

Comparative Example 2: Preparation of a cerium oxide doped with a single Cu

Comparative example  2-1: Ce: Cu Mole ratio = 0.95: 0.05

The cerium precursor cerium nitrate hydrate (Ce (NO ₃ ) ₃ ㆍ 6H ₂ O) and the copper precursor copper nitrate hydrate (CuN ₂ O ₆ ㆍ 3H ₂ O) have a molar ratio of Ce: Cu as their metal element of 0.95: 0.05. Dissolved in 100 mL of distilled water to prepare an aqueous solution.

An EDTA solution was prepared by mixing EDTA (Ethylenediaminetetraacetic acid) with ammonia water, and then the EDTA solution, the aqueous solution, and 30 mL of citric acid were mixed to prepare a mixed solution. Ammonia was added and titrated so that the mixed solution was at pH 10. In order to maintain the temperature of the mixed solution at 80 ° C, an EDTA complex was prepared by heating on a plate at 158 ° C.

The EDTA complex was heat-treated at 450 ° C in a heating mantle to evaporate impurities, and sintered by heating at 500 ° C for 3 hours in a kiln to prepare Ce _0.95 Cu _0.05 O _2-δ , which is a single doped cerium oxide.

Comparative Example 2-2: molar ratio of Ce: Cu = 0.9: 0.1

Ce _0.9 Cu _0.1 O _2-δ was prepared in the same manner as in Comparative Example 2-1, except that the molar ratio of Ce: Cu in Comparative Example 2-1 was 0.9: 0.1 instead of 0.95: 0.05.

Comparative Example 2-3: molar ratio of Ce: Cu = 0.8: 0.2

Comparative Example 2-1 Ce: 0.8 instead of 0.05: 0.95 molar ratio of Cu in the same manner as in Comparative Example 2-1 except that a 0.2 Ce _{0. 8} Cu _{0 . 2} O _{2 -δ} was prepared.

[Test Example]

Test Example 1: X-ray diffraction (XRD) analysis

XRD analysis was performed to confirm the oxide formation of the lattice substitution material on the surface of the cerium oxide.

Figure 1a shows the results of XRD analysis of a single doped cerium oxide Cu prepared according to Comparative Example 2. Referring to FIG. 1A, when the Cu material was incorporated into cerium oxide, it was confirmed that the oxide formation of the lattice substitution material was not seen to less than 20 mol%.

1B shows Ce ₀ prepared according to Examples 1-6 _{. 90} Ag _{0 . 01} Cu _{0 . 09} O _{2 -δ} and Ce ₀ prepared according to Examples 1-7 _{. 90} Ag _{0 . 02} Cu _{0 . The} results of XRD analysis of ₀₈ O _{2 -δ} are shown. When the 10 mol% Cu material in FIG. 1A was incorporated into cerium oxide, the AgCu co-doping combination was prepared at a total concentration ratio of 10 mol% because no oxide of the lattice substitution material was formed. However, referring to FIG. 1B, silver oxide was confirmed even when prepared at a concentration of 1 mol% silver (Ag).

1C shows the results of XRD analysis of cerium oxides co-doped with Ag and Cu of Examples 1-1 to 1-5 and cerium oxides co-doped with Ru and Cu of Example 2. Referring to FIG. 1C, it was confirmed that the AgCu combination did not form an oxide on the catalyst surface when the Ag 1 mol% and Cu 4 mol% concentrations, and the RuCu combination had the Ru 1 mol% and Cu 4 mol% concentrations.

Test Example 2: TEM and SEM-EDS image analysis

Figure 2a is CeO ₂ of Comparative Example 1, Ce ₀ of Example 1-1 _{. 95} Ag _{0 . 01} Cu _{0 . 04} O _{2 -δ} , Ce _0.95 Ru _0.01 Cu _0.04 O _{2-δ of} Example 2 and Ce ₀ of Comparative Example 2-1 _{. 95} Cu _{0 . 05 This is a} Transmission Electron Microscopy (TEM) image of O _{2 -δ} . 2B shows Ce ₀ prepared according to Example 1-1 _{. 95} Ag _{0 . 01} Cu _{0 . This} is an SEM-EDS (Scanning Electron Microscopy with Energy Dispersive Spectroscopy) image of ₀₄ O _{2 -δ} . 2A and 2B, it was confirmed that the lattice substitution materials were uniformly distributed on the catalyst surface.

Test Example 3: Raman spectrum analysis

3A to 3D are Ce ₀ of Comparative Example 2-1, respectively _{. 95} Cu _{0 . 05} O _{2 -δ} , Ce _0.95 Ag _0.01 Cu _0.04 O _2-δ of Example 1-1, Ce ₀ of Example 2 _{. 95} Ru _{0 . 01} Cu _{0 . It} shows the results of Raman spectrum analysis of ₀₄ O _{2 -δ} and CeO ₂ of Comparative Example 1. Referring to Figure 3a to 3d, the peak seen at 600cm ^-1 indicates the catalyst surface defects (oxygen vacancy), the strength ratio AgCu: 3.53%, Cu: 2.58%, RuCu: 1.98% AgCu combination group in the sample It was confirmed that it had the highest value.

Test Example 4: XPS (X-ray photoelectron spectroscopy) analysis

4A-4C show Ce ₀ prepared according to Example 1-1 _{. 95} Ag _{0 . 01} Cu _{0 . 04} O _{2 -δ} and Ce ₀ prepared according to Comparative Example 2-1 _{. 95} Cu _{0 . 05} shows the results of XPS analysis of O _{2 -δ} , and FIGS. 4D and 4E show the results of XPS analysis of Ce _0.95 Ag _0.01 Cu _0.04 O _2-δ prepared according to Example 1-1.

Referring to Figure 4a, Figure 4a is a result of the O 1s, the surface oxygen species that directly participate in the activity _{^{(O 2 -, O 2 2-}} , O -) to large, the area of that is, the number of the corresponding amount I could confirm.

Referring to FIG. 4B, when oxygen vacancy was formed on the surface of the catalyst, it was confirmed how easily or high oxygen vacancy could be formed as the oxidation number changed from Ce ^{4 +} to Ce ^{3 +} .

4C and 4D, it was confirmed that Cu species were mostly present on the surface of Cu ⁺ , and metallic Cu was not observed, so that lattice substitution was well performed.

Referring to Figure 4e, it was confirmed that most Ag species exist on the surface of Ag ⁺ , and metallic Ag is not observed.

Test Example 5: oxygen desorption ability of the catalyst surface

5A shows the result of confirming the desorption capacity of oxygen after adsorbing oxygen on the catalyst surface. The lower the oxygen desorption temperature, the easier it is to provide oxygen on the surface of the catalyst to the reactant. In the metal oxide, oxygen desorption is very important for the reaction. Referring to FIG. 5A, it was confirmed that AgCu co-doped cerium oxide desorbs oxygen more effectively at a lower temperature than other samples.

Test Example 6: Analysis of the activity of the catalyst

5B shows Ce ₀ of Example 1-1 _{. 95} Ag _{0 . 01} Cu _{0 . 04} O _{2 -δ} , Ce ₀ of Example 2 _{. 95} Ru _{0 . 01} Cu _{0 . 04} O _{2 -δ} , CeO ₂ of Comparative Example 1 and Ce ₀ of Comparative Example 2-1 _{. 95} Cu _{0 . 05} O ₂ is a graph showing the H ₂ consumption (H ₂ Consumption) of _-δ. When H ₂ is converted to H ₂ O, it is converted using catalyst surface oxygen. Referring to FIG. 5B, it was confirmed that it shows high activity at low temperature through consumption of H ₂ at low temperature.

6A is a graph showing the results of CO conversion under conditions of 1% CO, 1% O ₂ , and total flow rate of 100 ml / min under Ar flow, and FIG. 6B is a graph showing activation energy calculated using FIG. 6A. 6A and 6B, it was confirmed that AgCu co-doped cerium oxide has the lowest activation energy.

6c is a graph showing the catalytic reaction rate according to temperature. Referring to Figure 6c, it was confirmed that AgCu co-doped cerium oxide shows the highest reaction rate.

The scope of the present invention is indicated by the following claims rather than the above detailed description, and it should be interpreted that all changes or modified forms derived from the meaning and scope of the claims and equivalent concepts thereof are included in the scope of the present invention. do.

Claims (15)

It is a co-doped cerium oxide represented by the following formula (1),
A cerium oxide in which the co-doped cerium oxide is used as a catalyst in the oxidation reaction of carbon monoxide (CO);
[Formula 1]
M ¹ _x M ² _y Ce _{1- (x + y)} O _2-δ
In Chemical Formula 1,
M ¹ is silver (Ag), M ² is copper (Cu),
x is 0 <x≤0.2, y is 0 <y≤0.2, and δ is 0≤δ≤0.4. delete delete delete delete delete delete According to claim 1,
Co-doped cerium oxide, characterized in that the carbon monoxide is included in the combustion exhaust gas. In the method of manufacturing a co-doped cerium oxide,
The method of manufacturing the co-doped cerium oxide
(a) preparing a precursor aqueous solution containing a cerium precursor and two transition metal precursors;
(b) preparing an EDTA aqueous solution containing ethylenediaminetetraacetic acid (EDTA) and ammonia;
(c) preparing an aqueous EDTA complex solution containing the complex of the EDTA by mixing and reacting the precursor aqueous solution, the EDTA aqueous solution, and citric acid;
(d) drying the EDTA complex aqueous solution; And
(e) sintering the resultant of the dried step (d) by heat treatment to prepare a co-doped cerium oxide represented by Chemical Formula 1;
The two transition metal precursors are silver precursors and copper precursors,
Method for producing co-doped cerium oxide, wherein the co-doped cerium oxide is for use as a catalyst in the oxidation reaction of carbon monoxide (CO):
[Formula 1]
M ¹ _x M ² _y Ce _{1- (x + y)} O _2-δ
In Chemical Formula 1,
M ¹ is silver (Ag), M ² is copper (Cu),
x is 0 <x≤0.2, y is 0 <y≤0.2, and δ is 0≤δ≤0.4. The method of claim 9,
The cerium precursor is co-doped, characterized in that it comprises at least one selected from the group consisting of cerium nitrate hydrate (Ce (NO ₃ ) ₃ ㆍ 6H ₂ O) and cerium chloride hydrate (CeCl ₃ ㆍ 7H ₂ O). -doped) Method for manufacturing cerium oxide. delete The method of claim 9,
The silver precursor is silver nitrate (AgNO ₃ ), silver chloride (AgCl) and silver perchlorate (AgClO ₄ ) method for producing a co-doped (co-doped) cerium oxide, characterized in that it comprises at least one selected from the group consisting of. The method of claim 9,
The copper precursor comprises at least one selected from the group consisting of copper nitrate hydrate (CuN ₂ O ₆ ㆍ 3H ₂ O), copper hydroxide (Cu (OH) ₂ ) and copper chloride hydrate (CuCl ₂ ㆍ 2H ₂ O) Method for producing a co-doped cerium oxide, characterized in that. The method of claim 9,
Between steps (d) and (e)
Method of manufacturing a co-doped cerium oxide further comprising; evaporating the impurities of the dried product (d) at 400 to 470 ° C. (d ′). The method of claim 9,
Method of manufacturing a co-doped cerium oxide, characterized in that the sintering in step (e) is performed at 450 to 700 ° C.

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