JP2003326164A - Exhaust gas purifying catalyst, its manufacturing method, and exhaust gas purifier - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an exhaust gas purifying catalyst which can adsorb, desorb and clean NOx, is excellent especially in the adsorption performance of NOx, prevent sulfur poisoning, and easily remove the sulfur poisoning, a manufacturing method therefor, and an exhaust gas purifier. <P>SOLUTION: In the exhaust gas purifying catalyst, the upper surface side of a catalyst component arranged on a porous carrier contains a higher content of a cerium compound, and the lower surface side thereof contains a higher content of a cesium compound. A mixed solution of a solution of the soluble cerium compound and a solution of the soluble cesium compound is soaked and impregnated with a catalyst layer installed in the carrier to form the catalyst component part, thereby obtaining the exhaust gas purifying catalyst. A ternary catalyst and the exhaust gas purifying catalyst are disposed in order from the upstream side of an internal combustion engine or a combustion device to compose the exhaust gas purifier. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to hydrocarbons (HC) and carbon monoxide (C) in exhaust gas emitted from internal combustion engines such as automobiles (gasoline, diesel) and boilers.
TECHNICAL FIELD The present invention relates to an exhaust gas purifying catalyst for purifying O) and nitrogen oxides (NOx) and a method for manufacturing the same, and more particularly to an exhaust gas purifying catalyst that focuses on NOx purification when lean, a method for manufacturing the same, and an exhaust gas purifying apparatus.

[0002]

2. Description of the Related Art In recent years, the demand for fuel-efficient vehicles has been increasing due to the problem of exhaustion of petroleum resources and the problem of global warming, and the development of lean-burn vehicles has attracted attention for gasoline vehicles. In such a lean-burn vehicle, the exhaust gas atmosphere becomes an oxygen excess atmosphere (lean) compared to the theoretical air-fuel state during lean-burn driving, but when a normal three-way catalyst is applied in the lean region, excess oxygen Due to the influence, there is a problem that the NOx purification action becomes insufficient. Therefore, it has been desired to develop a catalyst that can purify NOx even if oxygen becomes excessive.

[0003]

[Problems to be Solved by the Invention]
Various catalysts for purifying Ox have been proposed. For example, as represented by a catalyst in which platinum (Pt) and lanthanum (La) are supported on a porous carrier (Japanese Unexamined Patent Publication No. 5-168860), NOx in a lean region is shown. A catalyst that absorbs NOx and releases NOx at the time of stoichiometry to purify it has been proposed. This catalyst is poisoned by sulfur-derived SOx contained in the fuel and the lubricating oil due to its NOx purification reaction mechanism, and its performance deteriorates. Since this poisoning by SOx is primary poisoning, if the catalyst is heated to a high temperature and SOx is desorbed, the poisoning is released.

However, the SOx desorption temperature is 650 ° C to 75 ° C.
The temperature is very high at 0 ° C., and even if it is temporary, in order to raise the temperature of the catalyst to that temperature, it is necessary to dispose the catalyst at a position close to the engine out. On the other hand, with such an arrangement, the temperature at the catalyst inlet is 350 ° C to
The temperature becomes as high as 500 ° C., and the NOx adsorption function is not sufficiently fulfilled. As a solution to this problem, as shown in the graph of FIG. 1, a method of using a strong alkali and satisfying the adsorption function even at high temperature can be considered. However, although the adsorption function is satisfied by the strong alkali, at the same time NO
This causes a decrease in the x-desorption function, and a strong alkali reduces the activity of the noble metal, resulting in a decrease in the NOx purification function. Therefore, the first problem is to perform desorption and purification of NOx in a NOx catalyst that uses a strong alkali at high temperature.

Further, in JP-A-2000-102728 and JP-A-2000-325791, in order to facilitate the release of S poisoning (S release at a lower temperature), the S release temperature is higher than that of alkali compounds. Low cerium compound N
There is proposed a method of disposing S on the Ox catalyst, temporarily adsorbing S to the cerium compound to prevent poisoning of the NOx catalyst on the lower surface side, and desorbing S from the Ce compound when S poison is released. This method is effective at first glance, but when a large amount of Ce compound is present in the outermost layer, a reducing material (hydrocarbon (H ₂ ) that reduces oxygen (O ₂ ) and NOx released from the Ce compound
C), carbon monoxide (CO), and hydrogen (H ₂ ) react with each other, and NOx reduction is not sufficiently performed, resulting in deterioration of NOx purification performance. Also, Ce compounds are NOx at high temperature.
Since the adsorption function is weak and no alkali compound is present in the outermost layer, the NOx adsorption function at that portion is deteriorated.
Therefore, the second problem is to suppress the S poisoning and to easily cancel the S poisoning while not further lowering the NOx purification function.

The present invention has been made in view of the above problems of the prior art, and an object of the present invention is to adsorb, desorb and purify NOx, and in particular, it has excellent NOx adsorption performance, and S An object of the present invention is to provide an exhaust gas purifying catalyst capable of suppressing poisoning and easily removing S poisoning, a method for manufacturing the same, and an exhaust gas purifying apparatus.

[0007]

Means for Solving the Problems As a result of intensive studies to solve the above problems, the present inventors have found that the above problems can be solved by containing a cerium compound and a cesium compound in the vicinity of a catalyst component in a certain arrangement. Find what you can solve,
The present invention has been completed.

That is, the exhaust gas purifying catalyst of the present invention contains more cerium compound on the upper surface side and more cesium compound on the lower surface side of the catalyst component portion arranged on the porous carrier. Characterize.

Further, in the method for producing an exhaust gas purifying catalyst according to the present invention, the catalyst layer is immersed and impregnated with a mixed solution containing a soluble cerium compound aqueous solution and a soluble cesium compound aqueous solution in a catalyst layer provided on a carrier. It is characterized by forming.

Further, the exhaust gas purifying apparatus of the present invention is characterized in that the three-way catalyst and the exhaust gas purifying catalyst are sequentially arranged from the upstream side of the exhaust passage of the internal combustion engine or the combustion apparatus.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION The exhaust gas purifying catalyst of the present invention will be described in detail below. In addition, in this specification, "%" shows a mass percentage unless otherwise specified.

As described above, the exhaust gas purifying catalyst of the present invention is formed by coating the catalyst component part on the porous carrier. The catalyst component part contains a cerium compound (Ce compound) and a cesium compound (Cs compound), of which the Ce compound is contained more in the upper surface side of the catalyst component part, and the Cs compound is the lower surface of the catalyst component part. More included on the side. With such a configuration, the adsorption performance, the desorption performance, and the purification performance of the NOx purification catalyst, especially the adsorption performance is improved, and further the S poisoning suppression and the S poisoning removal performance are improved. In the above catalyst component part, the "lower surface side" means the carrier contact surface side, and the "upper surface side" means the surface side facing it. Further, these are not particularly limited to the upper part and the lower part with the middle of the catalyst component part as a boundary, and the desired Ce amount,
It is a relative value determined according to the amount of Cs and the thickness of the catalyst component. Specifically, as shown in FIG. 2, when the catalyst component part has a two-layer structure, the upper catalyst layer is the upper side of the catalyst component layer and the lower catalyst layer is the lower side of the catalyst component layer.

Here, NOx by the exhaust gas purifying catalyst
The improvement of the performance of the catalyst will be described. By reducing the amount of Cs compound contained on the upper surface side of the catalyst component portion than on the lower surface side, deterioration of the noble metal as the NOx catalyst is prevented, and NO
x Purification performance can be sufficiently exhibited. Further, by increasing the amount of Cs compound contained on the lower surface side of the catalyst component part than on the upper surface side, the NOx adsorption function can be sufficiently exhibited. However, when the Cs compound is not included on the upper surface side of the catalyst component portion, or the Cs compound amount on the upper surface side of the catalyst component portion is 1/1 of the total Cs compound amount.
When it is less than 1, the NOx purification performance is extremely reduced. It is considered that this is because the NOx adsorption capacity near the upper surface side of the catalyst component part is extremely reduced. Therefore, a certain amount of Cs compound is required on the upper surface side of the catalyst component part, but the amount thereof is such that it does not cause deterioration of the noble metal that expresses NOx purification performance, specifically, 1 /% of the total amount of Cs compound.
It is preferably 11 or more and less than 1/2. In other words, the Cs compound contained in the catalyst component part preferably satisfies the following formula 0.1 ≦ Cs compound amount on the upper surface side of the catalyst component part / Cs compound amount on the lower surface side of the catalyst component part <1. The total amount of Cs ₂ O is preferably 20 g or more per 1 L of catalyst capacity.

Further, by increasing the amount of Ce compound contained on the upper surface side of the catalyst component portion than on the lower surface side, the reducing material is burned and the heat thereof is on the lower surface side (a portion containing a large amount of Cs compound).
NOx is desorbed from there. Further, by making the Ce compound contained on the lower surface side of the catalyst component portion smaller than that on the upper surface side, N strongly adsorbed on the lower surface side is obtained.
Ox is easily desorbed. This effect can be inferred from the fact that the NOx desorption performance is extremely deteriorated when the Ce compound is not contained at all on the lower surface side of the catalyst component part. At present, the cause of this is not clear, but it is considered that the balance of the distribution state of the Cs compound, the Ce compound and the noble metal is important for the desorption of NOx. However, if the amount of the Ce compound contained on the upper surface side of the catalyst component portion is too large, O ₂ released from the Ce compound reacts with the reducing material for reducing NOx, and the reducing material is consumed too much, NOx purification performance decreases. Therefore, specifically, the amount of Ce compounds contained on the upper surface side of the catalyst component is 1/2 or more of the total amount of Ce compounds 2 /
It is preferably less than 3. In other words, the Ce compound contained in the catalyst component part preferably satisfies the following formula 1 ≦ Ce compound content on the lower surface side of the catalyst component part / Ce compound content on the upper surface side of the catalyst component part <2. The total amount of Ce compounds is preferably 40 g or less as CeO ₂ per 1 L of the catalyst volume.

Further, suppression of S poisoning by the present exhaust gas purifying catalyst will be described. By increasing the amount of the Ce compound contained in the upper surface side of the catalyst component portion than in the lower surface side, S is adsorbed mainly on the upper surface side of the catalyst component portion and S poisoning occurs. At this time, since the Cs compound contained in the upper surface side of the catalyst component portion is small, the NOx purification performance is deteriorated due to S poisoning, but since the lower surface side of the catalyst component portion contains a large amount of Cs compound,
S-poisoning is less likely to occur, and deterioration of NOx purification performance can be minimized. Therefore, it is possible to make the entire catalyst less susceptible to S poisoning. For this reason, Ce is on the upper surface side.
Although it is desired to dispose as many compounds as possible, the NOx reducing material is consumed for the above reason, so it is not preferable to set it to 2/3 or more of the total Ce compound amount.

Further, S adsorbed on the Ce compound contained on the upper surface side of the catalyst component is more easily desorbed than S adsorbed on other alkali metals such as Cs. Easy to separate. Therefore, it is necessary to adsorb S on the upper surface side as much as possible. For this purpose, it is effective to increase the Ce compound amount or to thicken the upper surface side, but since these methods consume the NOx reducing material in the same manner as described above, the Ce compound amount is less than the total amount. 2/3
The above is not preferable. Further, it is not preferable to set the amount of Ce compound on the upper surface side to ½ or more of the total amount.
However, if the coating amount is too small, it is not desirable from the viewpoint of suppressing S poisoning, so it is preferable that the coating amount is 1/5 or more of the total coating amount.

As shown in FIG. 3, it is desirable that the amount of Ce compound contained in the catalyst component portion gradually increases toward the surface side, and the amount of Cs compound gradually increases toward the lower surface side. Is desirable. Further, the catalyst component part may be composed of two or more catalyst layers. Also in this case, similarly, it is preferable that the catalyst layer on the upper surface side has a larger content of the Ce compound and that the catalyst layer on the lower surface side of the catalyst layer has a larger content of the Cs compound. In particular, when the catalyst component part has a two-layer structure of an upper catalyst layer and a lower catalyst layer, the thickness of each layer is calculated by the following equation: 0.25 ≦ upper catalyst layer thickness / lower catalyst layer thickness It is preferable to satisfy ≦ 1. Further, the Ce compound contained in each layer is expressed by the following formula 1 ≦ Ce compound content of the lower catalyst layer / Ce of the upper catalyst layer.
It is preferable that the compound content ≦ 2 is satisfied. Further, the Cs compound contained in each layer preferably satisfies the following formula: 0.1 ≦ Cs compound content of upper catalyst layer / Cs compound content of lower catalyst layer <1. At this time, since the upper catalyst layer contains a larger amount of Ce compound, it is possible to burn the reducing material and transfer the heat to the lower catalyst layer. Further, since the lower catalyst layer contains more Cs compound, it is easy to desorb strongly adsorbed NOx.

Further, N in the exhaust gas is reduced by using a NOx catalyst.
In order to reduce Ox, it is necessary to effectively exhibit the following three functions. NOx adsorbing function This is a function to oxidize NOx in exhaust gas on a noble metal in an oxygen excess atmosphere (lean) and take it into an NOx adsorbent such as alkali. NOx desorption function A function of desorbing NOx adsorbed on the adsorbent and reacting it with the reducing agent on the noble metal under the atmosphere of reducing agent excess to the stoichiometric air-fuel ratio atmosphere (rich to stoichiometric). In addition, N
If Ox is not desorbed appropriately, the NOx adsorbent will be filled with NOx, and no more NOx can be adsorbed. NOx purification function It is a function of reacting NOx and a reducing material on a precious metal in a rich to stoichiometric manner.

If these functions are to be exhibited in the presence of a Cs compound, a reverse reaction may occur depending on the amount of reducing agent in a lean atmosphere, as shown in equations (1) and (2). (NOx adsorption reaction) CsCO ₃ + NO + 1 / 2O ₂ → CsNO ₃ + CO ₂ (1) (NOx desorption reaction) CsNO ₃ + 1 / 6C ₃ H ₆ → 1 / 2Cs ₂ CO ₃ + 1 / 2H ₂ O + NO (2)

That is, assuming that the velocity constant of equation 1 is K1 and the velocity constant of equation 2 is K2, when a large amount of reducing agent (propene as HC in equation 2) exists in the reaction atmosphere, even if lean, K1 and K2 The relationship becomes K2> K1, and the NOx desorption reaction becomes dominant. At this time, in order to satisfy K1> K2, the reducing agent in the reaction atmosphere may be removed. As such a method, specifically, the catalyst component part may be rhodium (Rh) and platinum (Pt) and / or palladium (P).
It is preferable to include d). In particular, the inclusion of Pd is most effective. However, if the amount of Pd is too small, it is difficult to obtain this effect sufficiently, and if the amount of Pd is too large, the reducing components (HC, CO
And H ₂ ) are consumed, and the NOx purification function may not work sufficiently. Therefore, it is preferable that the amount of Pd exists in the optimum range. Specifically, P in the catalyst component part
The ratio Pt / Pd between the t content and the Pd content is 1.1 to 4.
It is preferably 2. At this time, as shown in FIG. 4, the purification function becomes better while satisfying the adsorption function.

Further, Rh and Pt are provided on the upper surface side of the catalyst component portion.
It is preferable that Pd and / or Pd be included, and Pt and / or Pd be included on the lower surface side of the catalyst component part. As described above, P in the catalyst component part
The arrangement of d greatly affects the purification of NOx. That is, when Pd having a high effect of reducing the reducing material is present on the upper surface side of the catalyst component portion, the reducing material is consumed before the reducing material reaches the lower surface side of the catalyst component portion sufficiently, and the NOx purification function deteriorates. . Therefore, it is particularly preferable that Pd be present on the lower surface side of the catalyst component part as much as possible. For example, as shown in FIG. 5, in the catalyst component part having a two-layer structure, the smaller the amount of Pd contained in the upper catalyst layer is, the higher the NOx conversion rate is,
The highest conversion is obtained when Pd is not contained in the upper catalyst layer. However, after removal of S poisoning, the NOx conversion rate is large when Pd is present over the entire catalyst (Pd amount in the upper catalyst layer / Pd amount in the lower catalyst layer = 1). Although the detailed cause of this is not clear at present, it is considered that the S compound with Pd is more easily decomposed than the S compound with other noble metals. Taking the above into consideration, the ratio Pd _U / Pd _L between the Pd content (Pd _U ) on the upper surface side of the catalyst component portion and the Pd content (Pd _L ) on the lower surface side of the catalyst component portion is 0.
It is preferably -1.

The total amount of Rh, Pt or Pd, and the noble metal relating to any combination thereof is preferably 0.7 g or more and less than 5.7 g per 1 L of the catalyst.
A minimum of 0.7 g / L is required to develop the catalytic action, and even if the amount is increased to 5.7 g / L or more, there is almost no effect, which is disadvantageous in terms of cost.

Further, the Rh amount is the R with the Pt amount and the Pd amount.
There is an appropriate amount in the h ratio. Specifically, it is preferable that the following expression 3 ≦ (Pt + Pd) / Rh ≦ 10 is satisfied. While the amount of Rh has a great effect on the reduction of NOx, it is effective to set it in the above range in terms of resources and cost.

Furthermore, the thickness of the catalyst component part is also important. That is, when the upper surface side of the catalyst component portion is too thick, the reducing agent may not reach the lower surface side of the catalyst component portion and the desorption function may deteriorate, and when it is too thin, the lower surface side of the catalyst component portion with a large amount of Pd becomes relatively thick, After all, it results in consumption of the reducing material. Therefore, the thickness of the catalyst component upper surface side and the thickness of the catalyst component lower surface side satisfy the following formula: catalyst component upper surface side thickness / catalyst component lower surface side thickness = 0.25 to 1. Preferably, it is more preferably 0.6 to 0.7.

In addition to the Cs compound, a Ba compound or a Mg compound can be added to the catalyst component part. At this time, S poisoning is more easily released. Further, these compounds are preferably contained in a larger amount on the upper surface side of the catalyst component section than on the lower surface side of the catalyst component section. At this time, S is adsorbed similarly to the Ce compound, and further NOx adsorption performance of Ce or higher can be exhibited, so that the NOx purification performance is likely to be significantly improved. The reason why the S poison removal performance is improved is B
It is considered that the adsorbed S is taken in as a complex sulfate due to the interaction between a, Mg and Cs.

Furthermore, when a Ba compound and a Mg compound are contained, a part or all of them are compounded to form the following general formula Ba _x Mg _y (CO ₃ ) ₂ (where x and y are the respective elements). Atomic ratio, x = 0.
5 to 1.999, y = 0.001 to 1.5, x + y =
It is preferable to form a complex carbonate represented by 2.0). As shown in FIG. 6, when BaMg is combined with BaMg (CO ₃ ) ₂ , an XRD peak that is not found in BaCO ₃ appears, and durability at high temperature increases.
The aggregation of alkalis is reduced. This is considered to further facilitate the release of S poison.

The working air-fuel ratio in an internal combustion engine or the like using such an exhaust gas purifying catalyst is 15-50 and 10.
It is desirable to be 0 to 14.6, and if it is in this range, NOx can be efficiently purified. Further, the exhaust gas purifying catalyst of the present invention can be used in various shapes and can be used by supporting it on a refractory inorganic carrier. For example, it can be used by being carried on an integral structure type carrier such as a honeycomb structure made of a ceramic such as cordierite or a metal such as ferritic stainless steel. Further, it is desirable that such an exhaust gas purifying catalyst has high heat resistance in consideration of the situation of being exposed to high temperatures. Therefore, materials such as zirconia, lanthanum, and barium, which have been conventionally used for three-way catalysts, such as noble metals and alumina, which improve the heat resistance, may be appropriately added.

Next, the method for producing the exhaust gas purifying catalyst of the present invention will be described in detail. In the above exhaust gas purifying catalyst, after a catalyst component is first coated on a carrier to form a catalyst layer, the catalyst layer is dipped and impregnated with a mixed solution of a soluble Ce compound aqueous solution and a soluble Cs compound aqueous solution. It is obtained by adjusting the distribution state of the Ce compound and the Cs compound to form the catalyst component part. In this way, since the Ce compound and the Cs compound are impregnated at the same time,
S-poisoning release performance is further enhanced by sequentially impregnating the Ce compound and the Cs compound. At present, it is not clear about this effect, but Ce around the catalyst component such as precious metal
It can be inferred that Cs and Cs are optimally distributed. In addition, the Ce compound and the Cs compound when performing such simultaneous impregnation are
More preferably, it is used in the form of Ce acetate and Cs acetate, and then Ce nitrate and Cs nitrate are preferably used.

Next, the exhaust gas purifying apparatus of the present invention will be described in detail. Such an exhaust gas purifying device comprises a three-way catalyst and the above-mentioned exhaust gas purifying catalyst which are sequentially arranged from the upstream side of the exhaust passage of the internal combustion engine or the combustion device. With such a configuration, excellent NOx purification performance can be exhibited even when oxygen becomes excessive due to the use of the three-way catalyst in the lean region.

[0030]

EXAMPLES 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 Powder A was obtained by impregnating activated alumina having a specific top surface side product of 180 m ^{2 with} a dinitrodiamine platinum solution, drying and firing it in air at 400 ° C. for 1 hour. The Pt concentration of this powder was 1.0%. Specific surface side product is 1
80 m ² of activated alumina was impregnated with a Rh nitrate solution, dried and then calcined in air at 400 ° C. for 1 hour to obtain a powder B. The Rh concentration of this powder was 1.0%. 72 powder A
0.0 g, powder B 150.0 g, alumina sol 30
g and 900 g of water were put into a magnetic ball mill, mixed and pulverized to obtain a slurry liquid. This slurry liquid was attached to a cordierite-based monolith carrier (1.2 L, 900 cells), excess slurry in the cells was removed by an air stream, and the mixture was dried at 130 ° C and then calcined at 400 ° C for 1 hour to obtain a catalyst. Ingredient part 30
0 g / L of catalyst was obtained. This catalyst was immersed in a mixed aqueous solution of cesium acetate and cerium acetate, and cesium was added to the catalyst.
Impregnated with cerium. The amount of cesium is 30 as Cs ₂ O
The amount of g / L and the amount of cerium were 10 g / L as CeO ₂ .

In this catalyst, the thickness of the following formula: catalyst component upper surface side (a large amount of Ce compound and less Cs compound) / catalyst component lower surface side (a higher amount of Ce compound, less Cs compound) thickness The coating thickness ratio represented by the above was 0.6. Further, the content ratio of the cerium compound represented by the following formula: Ce compound content on the upper surface side of the catalyst component portion / Ce compound content on the lower surface side of the catalyst component portion was 1.1. Further, the content ratio of the cesium compound represented by the following formula: Cs compound content on the upper surface side of the catalyst component / Cs compound content on the lower surface side of the catalyst component was 0.5.

Example 2 Powder C was obtained by impregnating activated alumina having a specific upper surface side product of 180 m ^{2 with} a palladium nitrate solution, drying and calcining in air at 400 ° C. for 1 hour. The Pd concentration of this powder was 1.0%. Powder A 540.0
g, 150.0 g of powder B, 180.0 g of powder C, 30 g of alumina sol and 900 g of water were charged into a magnetic ball mill and mixed and pulverized to obtain a slurry liquid. This slurry liquid is used as a cordierite monolith carrier (1.2 L, 900 cells)
To remove the excess slurry in the cell by air flow, dried at 130 ℃, and baked at 400 ℃ for 1 hour,
A catalyst having a catalyst component portion of 300 g / L was obtained. This catalyst was immersed in a mixed aqueous solution of cesium acetate and cerium acetate to impregnate the catalyst with cesium and cerium. Cs amount is Cs
₂ O is 30 g / L, and the amount of cerium is 1 as CeO _2.
It is 0 g / L.

In this catalyst, the coating thickness ratio is 0.6.
3, the content ratio of the cerium compound was 1.2, and the content ratio of the cesium compound was 0.55.

Example 3 Powder D was obtained by impregnating activated alumina with a specific top surface side product of 180 m ^{2 with} a dinitrodiamine platinum solution, drying and firing in air at 400 ° C. for 1 hour. The Pt concentration of this powder was 0.8%. Specific surface side product is 1
80 m ² of activated alumina was impregnated with a dinitrodiamine platinum solution, dried and then baked in air at 400 ° C. for 1 hour to obtain a powder E. The Pt concentration of this powder was 0.4%. Activated ceria having a specific surface area of 120 m ² was impregnated with a dinitrodiamine platinum solution, dried and then fired in air at 400 ° C. for 1 hour to obtain a powder F. The Pt concentration of this powder was 1.5%. 724.5 g of powder E, 42.3 g of powder F,
88.2 g of activated alumina, 45 g of alumina sol and 900 g of water were put into a magnetic ball mill, and mixed and pulverized to obtain a slurry liquid. This slurry liquid was attached to a cordierite-based monolith carrier (1.2 L, 900 cells), excess slurry in the cells was removed by an air stream, and the mixture was dried at 130 ° C and then calcined at 400 ° C for 1 hour to obtain a catalyst. Component part 300g / L
The catalyst was obtained. On this catalyst component part, powder D was added 543.
6 g, powder F 63.5 g, powder B 212.4 g, activated alumina 35.5 g, alumina sol 45 g, water 9
00 g was put into a magnetic ball mill, the slurry liquid obtained by mixing and pulverizing was adhered, the excess slurry in the cell was removed by an air stream, and the mixture was dried at 130 ° C. and then calcined at 400 ° C. for 1 hour to obtain a catalyst component. Part of 200 g / L of catalyst was obtained. This catalyst was immersed in a mixed aqueous solution of cesium acetate and cerium acetate to impregnate the catalyst with cesium and cerium. The amount of cesium is 50 g / L as Cs ₂ O, and the amount of cerium is CeO ₂
Is 10 g / L. The amount of Ce other than impregnation is 2
It is 8.2 g / L. An EPMA image of this catalyst is shown in FIG.

In this catalyst, the coating thickness ratio is 0.6.
7. The content ratio of the cerium compound was 1.2, and the content ratio of the cesium compound was 0.43.

Example 4 The catalyst component part obtained in Example 3 was immersed in a mixed aqueous solution of cesium acetate, barium acetate, magnesium acetate and cerium acetate, and cesium, barium, magnesium and cerium were added to the catalyst. Impregnated. The amount of cesium is 50 g / L as Cs ₂ O, the amount of barium is 10 g / L as BaO, the amount of magnesium is 5 g / L as MgO, and the amount of cerium is 10 g / L as CeO _2.
Met. Moreover, the amount of Ce other than the impregnation was 28.2 g / L.

In this catalyst, the coating thickness ratio is 0.6.
7. The content ratio of the cerium compound was 1.1, and the content ratio of the cesium compound was 0.33.

Example 5 An exhaust gas purifying catalyst of this example was obtained by repeating the same operation as in Example 3 except that the coating thickness ratio was 0.25.

Example 6 An exhaust gas purifying catalyst of this example was obtained by repeating the same operation as in Example 3 except that the coating thickness ratio was 0.9.

Example 7 Powder G was obtained by impregnating activated alumina having a specific surface area of 180 m ^{2 with} a palladium nitrate solution, drying and firing at 400 ° C. for 1 hour in air. The Pd concentration of this powder was 0.8%. Specific surface side product is 180m
The activated alumina of ² was impregnated with a palladium nitrate solution, dried and then calcined in air at 400 ° C. for 1 hour to obtain a powder H. The Pd concentration of this powder was 0.4%. 22 powder H
1.1 g, powder E 503.7 g, powder F 42.3
g, activated alumina 87.9 g, alumina sol 45
g and 900 g of water were put into a magnetic ball mill and mixed and pulverized to obtain a slurry liquid. This slurry liquid was attached to a cordierite-based monolith carrier (1.2 L, 900 cells), excess slurry in the cells was removed by an air stream, and the mixture was dried at 130 ° C and then calcined at 400 ° C for 1 hour to obtain a catalyst. Ingredient part 300
g / L of catalyst was obtained. On this catalyst component part, 1 powder G
65.6 g, powder D 378 g, powder F 63.5 g,
Powder B (212.4 g), activated alumina (35.5 g), alumina sol (45 g) and water (900 g) were charged into a magnetic ball mill, and the slurry liquid obtained by mixing and pulverizing was attached to remove excess slurry in the cell by air flow. After removing and drying at 130 ° C, it was calcined at 400 ° C for 1 hour to obtain a catalyst component of 200 g /
L catalyst was obtained. This catalyst was immersed in a mixed aqueous solution of cesium acetate and cerium acetate to impregnate the catalyst with cesium and cerium. The amount of cesium is 50 g / Cs ₂ O
The amount of L and cerium is 10 g / L as CeO ₂ . Moreover, the amount of Ce other than the impregnation is 28.2 g / L.

In this catalyst, the coating thickness ratio is 0.6.
7. The content ratio of the cerium compound was 1.2, and the content ratio of the cesium compound was 0.45. Also, Pt
/ Pd ratio is 3, Pd _U / Pd _L ratio is 1, (Pt + Pd)
The / Rh ratio was 5.

(Example 8) 441.9 g of powder H, 282.9 g of powder E, 42.3 g of powder F, 87.9 g of activated alumina, 45 g of alumina sol and 900 g of water were put into a magnetic ball mill and mixed. It was crushed to obtain a slurry liquid.
This slurry liquid is used as a cordierite monolith carrier (1.2
L, 900 cells), remove excess slurry in the cells by air flow and dry at 130 ° C, then 400 ° C
It was calcined for 1 hour to obtain a catalyst of 300 g / L of catalyst component. On this catalyst component part, 543.6 g of powder D, 63.5 g of powder F, 212.4 g of powder B, 35.5 g of activated alumina, 45 g of alumina sol, and 900 g of water were charged into a magnetic ball mill, and mixed and ground. The slurry thus obtained was adhered, excess slurry in the cell was removed by an air stream, and the slurry was dried at 130 ° C. and then calcined at 400 ° C. for 1 hour to obtain a catalyst component part of 200 g / L catalyst. This catalyst was immersed in a mixed aqueous solution of cesium acetate and cerium acetate to impregnate the catalyst with cesium and cerium. The amount of cesium is Cs ₂ O
Is 50 g / L, and the amount of cerium is 10 g as CeO _2.
/ L. Also, the amount of Ce other than impregnation is 28.2 g / L
Is.

In this catalyst, the coating thickness ratio is 0.6.
7. The content ratio of the cerium compound was 1.2, and the content ratio of the cesium compound was 0.45. Also, Pt
/ Pd ratio is 3, Pd _U / Pd _L ratio is 0, (Pt + Pd)
The / Rh ratio was 5.

(Example 9) 401.7 g of powder H, 323.3 g of powder E, 42.3 g of powder F, 87.7 g of activated alumina, 45 g of alumina sol and 900 g of water were charged into a magnetic ball mill and mixed. It was crushed to obtain a slurry liquid.
This slurry liquid is used as a cordierite monolith carrier (1.2
L, 900 cells), remove excess slurry in the cells by air flow and dry at 130 ° C, then 400 ° C
It was calcined for 1 hour to obtain a catalyst of 300 g / L of catalyst component. On this catalyst component part, 301.1 g of powder G, 242.6 g of powder D, 63.5 g of powder F and 21 of powder B were placed.
2.4 g of activated alumina, 35.4 g of activated alumina, 45 g of alumina sol, and 900 g of water were put into a magnetic ball mill, and the slurry liquid obtained by mixing and pulverizing was attached to the slurry, and the excess slurry in the cell was removed by an air flow. 400 after drying at ℃
The mixture was calcined at 0 ° C. for 1 hour to obtain a catalyst component part of 200 g / L. This catalyst was immersed in a mixed aqueous solution of cesium acetate and cerium acetate to impregnate the catalyst with cesium and cerium. The amount of cesium was 50 g / L as Cs ₂ O, and the amount of cerium was 10 g / L as CeO ₂ . Moreover, the amount of Ce other than the impregnation was 28.2 g / L.

In this catalyst, the coating thickness ratio is 0.6.
7. The content ratio of the cerium compound was 1.2, and the content ratio of the cesium compound was 0.45. Also, Pt
/ Pd ratio is 1.2, Pd _U / Pd _L ratio is 1, (Pt + P
The d) / Rh ratio was 5.

(Example 10) 176.7 g of powder H, 548.1 g of powder E, 42.3 g of powder F, 87.9 g of activated alumina, 45 g of alumina sol and 900 g of water were charged into a magnetic ball mill and mixed. It was crushed to obtain a slurry liquid. This slurry liquid was attached to a cordierite monolith carrier (1.2 L, 900 cells), excess slurry in the cells was removed by an air stream, and the slurry was dried at 130 ° C.
The mixture was calcined at 400 ° C. for 1 hour to obtain a catalyst having a catalyst component portion of 300 g / L. On this catalyst component part, powder G is 132.3
g, powder D 411.3 g, powder F 63.5 g, powder B 212.4 g, activated alumina 35.5 g, alumina sol 45 g, and water 900 g were charged into a magnetic ball mill and mixed to obtain a slurry. The liquid is allowed to adhere, excess slurry in the cell is removed by air flow, and the cell is dried at 130 ° C. and then calcined at 400 ° C. for 1 hour to obtain a catalyst component portion of 200 g / L.
The catalyst was obtained. This catalyst was immersed in a mixed aqueous solution of cesium acetate and cerium acetate to impregnate the catalyst with cesium and cerium. The amount of cesium is 50 g / L as Cs ₂ O,
The amount of cerium was 10 g / L as CeO ₂ . Moreover, the amount of Ce other than the impregnation was 28.2 g / L.

In this catalyst, the coating thickness ratio is 0.6.
7. The content ratio of the cerium compound was 1.2, and the content ratio of the cesium compound was 0.45. Also, Pt
/ Pd ratio is 4, Pd _U / Pd _L ratio is 1, (Pt + Pd)
The / Rh ratio was 5.

(Example 11) 198.8 g of powder H, 437.9 g of powder E, 42.3 g of powder F, 176 g of activated alumina, 45 g of alumina sol and 900 g of water were charged into a magnetic ball mill and mixed and pulverized. The slurry liquid was obtained.
This slurry liquid is used as a cordierite monolith carrier (1.2
L, 900 cells), remove excess slurry in the cells by air flow and dry at 130 ° C, then 400 ° C
It was calcined for 1 hour to obtain a catalyst of 300 g / L of catalyst component. On this catalyst component part, 149.1 g of powder G, 328.4 g of powder D, 63.5 g of powder F and 31 of powder B were added.
8.2 g, 40.8 g of alumina sol, and 900 g of water were put into a magnetic ball mill, and a slurry liquid obtained by mixing and pulverizing was attached to remove excess slurry in the cell by an air flow and dried at 130 ° C. And calcined at 400 ° C. for 1 hour to obtain a catalyst having a catalyst component portion of 200 g / L. This catalyst was immersed in a mixed aqueous solution of cesium acetate and cerium acetate to impregnate the catalyst with cesium and cerium. The amount of cesium is Cs ₂ O
Is 50 g / L, and the amount of cerium is 10 g as CeO _2.
/ L. Also, the amount of Ce other than impregnation is 28.2 g / L
Is.

In this catalyst, the coating thickness ratio is 0.6.
7. The content ratio of the cerium compound was 1.2, and the content ratio of the cesium compound was 0.45. Also, Pt
/ Pd ratio is 3, Pd _U / Pd _L ratio is 1, (Pt + Pd)
The / Rh ratio was 3.

(Example 12) 241.2 g of powder H, 564.6 g of powder E, 42.3 g of powder F, 6.9 g of activated alumina, 45 g of alumina sol and 900 g of water were put into a magnetic ball mill and mixed. It was crushed to obtain a slurry liquid.
This slurry liquid is used as a cordierite monolith carrier (1.2
L, 900 cells), remove excess slurry in the cells by air flow and dry at 130 ° C, then 400 ° C
It was calcined for 1 hour to obtain a catalyst of 300 g / L of catalyst component. On this catalyst component part, 180.9 g of powder G, 423.5 g of powder D, 63.5 g of powder F, and 11 of powder B were placed.
5.7 g, activated alumina 71.4 g, alumina sol 45 g, and water 900 g were put into a magnetic ball mill, and the slurry liquid obtained by mixing and pulverizing was attached, and excess slurry in the cell was removed by an air flow to remove 130 400 after drying at ℃
The mixture was calcined at 0 ° C. for 1 hour to obtain a catalyst component part of 200 g / L. This catalyst was immersed in a mixed aqueous solution of cesium acetate and cerium acetate to impregnate the catalyst with cesium and cerium. The amount of cesium is 50 g / L as Cs ₂ O, and the amount of cerium is 10 g / L as CeO ₂ . Moreover, the amount of Ce other than the impregnation is 28.2 g / L.

In this catalyst, the coating thickness ratio is 0.6.
7. The content ratio of the cerium compound was 1.2, and the content ratio of the cesium compound was 0.45. Also, Pt
/ Pd ratio is 3, Pd _U / Pd _L ratio is 1, (Pt + Pd)
The / Rh ratio was 10.

Example 13 The catalyst component part obtained in Example 3 was immersed in an aqueous cerium acetate solution to impregnate the catalyst with cerium. Then, the catalyst was immersed in an aqueous cesium acetate solution to impregnate the catalyst with cesium. The amount of cesium is 50 g / L as Cs ₂ O, and the amount of cerium is CeO ₂
Is 10 g / L. The amount of Ce other than impregnation is 2
It is 8.2 g / L.

In this catalyst, the coating thickness ratio is 0.6.
7. The content ratio of the cerium compound was 1.2, and the content ratio of the cesium compound was 0.40.

(Embodiment 14) Specific upper surface side product is 180 m^Twoof
Activated alumina is impregnated with cerium nitrate solution, dried and then air
The powder was obtained by baking at 400 ° C. for 1 hour. Of this powder
The Ce concentration was 5.6%. Dinitrodia in this powder
Impregnate with minplatinum solution and dry for 1 hour at 400 ℃ in air
Calcination gave powder I. The Pt concentration of this powder is 0.8
%Met. Specific surface side product is 180m^TwoOf activated alumina
After impregnating with cerium nitrate solution and drying, 1 at 400 ℃ in air
It was calcined for a time to obtain a powder. The Ce concentration of this powder was 1.
It was 3%. Dinitrodiamine platinum solution to this powder
Impregnate and dry, then burn in air at 400 ° C for 1 hour to obtain powder
I got J. The Pt concentration of this powder was 0.4%. powder
724.5 g of powder J, 42.3 g of powder F, activated aluminum
88.2g of water, 45g of alumina sol, 900g of water
Put into a magnetic ball mill, mix and grind to obtain a slurry liquid.
It was This slurry liquid is used as a cordierite monolith carrier.
(1.2 L, 900 cells), and attach the cells by air flow
After removing the excess slurry inside and drying at 130 ℃,
Baking at 400 ℃ for 1 hour, touch the catalyst component part 300g / L
I got a medium. On this catalyst component part, powder I was added to 543.6.
g, powder F 63.5 g, powder B 212.4 g, activity
Alumina 35.5 g, alumina sol 45 g, water 90
Slurry obtained by putting 0 g into a magnetic ball mill and mixing and pulverizing
Liquid and attach excess liquid in the cell by air flow.
Removed and dried at 130 ° C, then baked at 400 ° C for 1 hour
Then, a catalyst having a catalyst component portion of 200 g / L was obtained. Of this catalyst
CeO is CeO_TwoIs 38.2 g / L. This
Immersing the catalyst in a cesium acetate aqueous solution,
Impregnated with um. Cs amount is Cs _Two50 g / O
It is L.

In this catalyst, the coating thickness ratio is 0.6.
7. The content ratio of the cerium compound was 1.2, and the content ratio of the cesium compound was 0.43.

(Example 15) 60.3 g of powder E, 42.3 g of powder F, 752.4 g of activated alumina, 45 g of alumina sol and 900 g of water were put into a magnetic ball mill, and mixed and pulverized to obtain a slurry liquid. It was This slurry liquid was attached to a cordierite-based monolith carrier (1.2 L, 900 cells), excess slurry in the cells was removed by an air stream, and the mixture was dried at 130 ° C and then calcined at 400 ° C for 1 hour to obtain a catalyst. A catalyst having a component part of 300 g / L was obtained. On this catalyst component part, 45 g of powder D, 63.5 g of powder F and 5 of powder B were added.
2.5g, activated alumina 694g, alumina sol 4
5 g of water and 900 g of water were put into a magnetic ball mill, and the slurry liquid obtained by mixing and pulverizing was adhered, and the excess slurry in the cell was removed by an air flow and dried at 130 ° C., then 400 ° C.
Calcination was carried out for 1 hour to obtain a catalyst having a catalyst component portion of 200 g / L. This catalyst was immersed in a mixed aqueous solution of cesium acetate and cerium acetate to impregnate the catalyst with cesium and cerium. The amount of cesium is 50 g / L as Cs ₂ O, and the amount of cerium is 10 g / L as CeO ₂ . Moreover, the amount of Ce other than the impregnation is 28.2 g / L.

In this catalyst, the coating thickness ratio is 0.6.
7. The content ratio of the cerium compound was 1.2, and the content ratio of the cesium compound was 0.45.

Example 16 An exhaust gas purifying catalyst of this example was obtained by repeating the same operation as in Example 3 except that the coating thickness ratio was 0.2.

Example 17 An exhaust gas purifying catalyst of this example was obtained by repeating the same operation as in Example 3 except that the coating thickness ratio was 1.1.

Example 18 Activated alumina having a specific surface area of 180 m ² was impregnated with a cerium nitrate solution, dried and calcined in air at 400 ° C. for 1 hour to obtain a powder. The Ce concentration of this powder was 10.1%. This powder was impregnated with a dinitrodiamine platinum solution, dried and then baked in air at 400 ° C. for 1 hour to obtain a powder M. The Pt concentration of this powder is 0.
It was 8%. 724.5 g of powder E and 35.
7 g, activated alumina 94.8 g, alumina sol 45
g and 900 g of water were put into a magnetic ball mill and mixed and pulverized to obtain a slurry liquid. This slurry liquid was attached to a cordierite-based monolith carrier (1.2 L, 900 cells), excess slurry in the cells was removed by an air stream, and the mixture was dried at 130 ° C and then calcined at 400 ° C for 1 hour to obtain a catalyst. Ingredient part 300
g / L of catalyst was obtained. On this catalyst component part, powder M
43.6 g, powder F 63.5 g, powder B 212.4 g
g, activated alumina 35.5 g, alumina sol 45
g, 900 g of water were charged into a magnetic ball mill, and a slurry liquid obtained by mixing and pulverizing was adhered, excess slurry in the cell was removed by an air stream, and the slurry was dried at 130 ° C., and then calcined at 400 ° C. for 1 hour. A catalyst having a catalyst component portion of 200 g / L was obtained.
The amount of cerium in this catalyst was 38.2 g / L as CeO _2.
Met. Immersing this catalyst in an aqueous solution of cesium acetate,
Cesium was impregnated in the catalyst. The amount of cesium was 50 g / L as Cs ₂ O. The coating thickness ratio of this catalyst is 0.6
7, the amount ratio of the cerium compound is 2.2, and the amount ratio of the cesium compound is 0.43.

(Example 19) Specific top surface side product is 180 m^Twoof
Impregnate activated alumina with cesium acetate solution, dry and air
The powder was obtained by baking at 400 ° C. for 1 hour. Of this powder
The Cs concentration was 20.7%. Dinitrodi
Impregnated with amine platinum solution and dried at 400 ℃ in air for 1 hour
Firing was performed to obtain powder Q. The Pt concentration of this powder is 0.
It was 4%. 724.5 g of powder Q and 42.
3 g, activated alumina 88.2 g, alumina sol 45
g and 900 g of water are charged into a magnetic ball mill, mixed and ground.
The slurry liquid was obtained. This slurry liquid is used for cordierite
Attach it to a Norris carrier (1.2 L, 900 cells) and air
Remove excess slurry in the cell by flow and dry at 130 ° C.
After being dried, it is calcined at 400 ° C. for 1 hour, and the catalyst component part 300
g / L of catalyst was obtained. Onto this catalyst component part, powder D 5
43.6 g, powder F 63.5 g, powder B 212.4 g
g, activated alumina 35.5 g, alumina sol 45
g and 900 g of water are charged into a magnetic ball mill, mixed and ground.
The slurry liquid obtained from
After removing the slurry and drying at 130 ℃, at 400 ℃
The mixture was calcined for 1 hour to obtain a catalyst component portion of 200 g / L.
The amount of cesium in this catalyst is Cs_Two50 g / L as O
It was. The catalyst is immersed in an aqueous cerium acetate solution to
It was impregnated with cerium. CeO is CeO _TwoAs
It was 10 g / L. Moreover, the amount of Ce other than the impregnation is 28.
It was 2 g / L. The coating thickness ratio of this catalyst was 0.67.
The cerium compound amount ratio is 1.2, and the cesium compound
The quantity ratio was 0.02.

(Example 20) Activated alumina having a specific surface area of 180 m ² was impregnated with a cerium nitrate solution, dried and then calcined in air at 400 ° C for 1 hour to obtain a powder. The Ce concentration of this powder was 4.1%. This powder was impregnated with a dinitrodiamine platinum solution, dried and then baked in air at 400 ° C. for 1 hour to obtain a powder R. The Pt concentration of this powder is 0.8
%Met. Activated alumina having a specific surface area of 180 m ² was impregnated with a cerium nitrate solution, dried, and then dried at 400 ° C. in air for 1 hour.
It was calcined for a time to obtain a powder. The Ce concentration of this powder is 2.
It was 1%. This powder was impregnated with a dinitrodiamine platinum solution, dried and then baked in air at 400 ° C. for 1 hour to obtain a powder S. The Pt concentration of this powder was 0.4%. 724.5 g of powder S, 42.3 g of powder F, 88.2 g of activated alumina, 45 g of alumina sol and 900 g of water were put into a magnetic ball mill, and mixed and pulverized to obtain a slurry liquid. This slurry liquid was attached to a cordierite monolith carrier (1.2 L, 900 cells), excess slurry in the cells was removed by an air stream, and the slurry was dried at 130 ° C.
The mixture was calcined at 400 ° C. for 1 hour to obtain a catalyst having a catalyst component portion of 300 g / L. On this catalyst component part, powder R was added to 543.6.
g, powder F 63.5 g, powder B 212.4 g, activated alumina 35.5 g, alumina sol 45 g, water 90
0 g was put into a magnetic ball mill, the slurry liquid obtained by mixing and pulverizing was adhered, the excess slurry in the cell was removed by an air flow, and the mixture was dried at 130 ° C. and then calcined at 400 ° C. for 1 hour to obtain a catalyst component. Part of 200 g / L of catalyst was obtained. The cerium amount of this catalyst was 38.2 g / L as CeO ₂ .
The catalyst was dipped in an aqueous solution of cesium acetate to impregnate the catalyst with cesium. The amount of cesium is 50 g as Cs ₂ O
Was / L. The coating thickness ratio of this catalyst is 0.67,
The amount ratio of the cerium compound was 1.0, and the amount ratio of the cesium compound was 0.43.

(Example 21) 110.4 g of powder H, 614.4 g of powder E, 42.3 g of powder F, 87.9 g of activated alumina, 45 g of alumina sol and 900 g of water were charged into a magnetic ball mill and mixed. It was crushed to obtain a slurry liquid. This slurry liquid was attached to a cordierite monolith carrier (1.2 L, 900 cells), excess slurry in the cells was removed by an air stream, and the slurry was dried at 130 ° C.
The mixture was calcined at 400 ° C. for 1 hour to obtain a catalyst having a catalyst component portion of 300 g / L. On the catalyst component part, powder G is 248.4.
g, powder D 295.2 g, powder F 63.5 g, powder B 212.4 g, activated alumina 35.5 g, alumina sol 45 g, water 900 g were charged into a magnetic ball mill and mixed and pulverized to obtain a slurry. The liquid is allowed to adhere, excess slurry in the cell is removed by air flow, and the cell is dried at 130 ° C. and then calcined at 400 ° C. for 1 hour to obtain a catalyst component portion of 200 g / L.
The catalyst was obtained. This catalyst was immersed in a mixed aqueous solution of cesium acetate and cerium acetate to impregnate the catalyst with cesium and cerium. The amount of cesium is 50 g / L as Cs ₂ O,
The amount of cerium was 10 g / L as CeO ₂ . Moreover, the amount of Ce other than the impregnation was 28.2 g / L. The coating thickness ratio of this catalyst was 0.67, the amount ratio of the cerium compound was 1.2, and the amount ratio of the cesium compound was 0.45. Also, the Pt / Pd ratio is 3, the Pd _U / Pd _L ratio is 3,
The (Pt + Pd) / Rh ratio was 5.

(Example 22) 490.8 g of powder H, 234 g of powder E, 42.3 g of powder F, 87.9 g of activated alumina, 45 g of alumina sol, 900 g of water were charged into a magnetic ball mill and mixed and ground. The slurry liquid was obtained. This slurry liquid is used as a cordierite monolith carrier (1.2
L, 900 cells), remove excess slurry in the cells by air flow and dry at 130 ° C, then 400 ° C
It was calcined for 1 hour to obtain a catalyst of 300 g / L of catalyst component. On this catalyst component part, 368.1 g of powder G, 175.5 g of powder D, 63.5 g of powder F, and 21 of powder B were added.
2.4 g of activated alumina, 35.5 g of activated alumina, 45 g of alumina sol, and 900 g of water were put into a magnetic ball mill, and the slurry liquid obtained by mixing and pulverizing was attached, and the excess slurry in the cell was removed by an air flow. 400 after drying at ℃
The mixture was calcined at 0 ° C. for 1 hour to obtain a catalyst component part of 200 g / L. This catalyst was immersed in a mixed aqueous solution of cesium acetate and cerium acetate to impregnate the catalyst with cesium and cerium. The amount of cesium was 50 g / L as Cs ₂ O, and the amount of cerium was 10 g / L as CeO ₂ . Moreover, the amount of Ce other than the impregnation was 28.2 g / L. The coating thickness ratio of this catalyst was 0.67, and the amount ratio of the cerium compound was 1.
2 and the amount ratio of the cesium compound was 0.45. Also,
The Pt / Pd ratio is 0.8, the Pd _U / Pd _L ratio is 1, (Pt
The + Pd) / Rh ratio was 5.

(Example 23) 147.3 g of powder H, 577.5 g of powder E, 42.3 g of powder F, 87.9 g of activated alumina, 45 g of alumina sol and 900 g of water were put into a magnetic ball mill and mixed. It was crushed to obtain a slurry liquid. This slurry liquid was attached to a cordierite monolith carrier (1.2 L, 900 cells), excess slurry in the cells was removed by an air stream, and the slurry was dried at 130 ° C.
The mixture was calcined at 400 ° C. for 1 hour to obtain a catalyst having a catalyst component portion of 300 g / L. On this catalyst component part, powder G
g, powder D 433.4 g, powder F 63.5 g, powder B 212.4 g, activated alumina 35.4 g, alumina sol 45 g, and water 900 g were charged into a magnetic ball mill and mixed to obtain a slurry. The liquid is allowed to adhere, excess slurry in the cell is removed by air flow, and the cell is dried at 130 ° C. and then calcined at 400 ° C. for 1 hour to obtain a catalyst component portion of 200 g / L.
The catalyst was obtained. This catalyst was immersed in a mixed aqueous solution of cesium acetate and cerium acetate to impregnate the catalyst with cesium and cerium. The amount of cesium is 50 g / L as Cs ₂ O,
The amount of cerium was 10 g / L as CeO ₂ . Moreover, the amount of Ce other than the impregnation was 28.2 g / L. The coating thickness ratio of this catalyst was 0.67, the amount ratio of the cerium compound was 1.2, and the amount ratio of the cesium compound was 0.45. Further, the Pt / Pd ratio is 5, the Pd _U / Pd _L ratio is 1,
The (Pt + Pd) / Rh ratio was 5.

(Example 24) 244.8 g of powder H, 575.7 g of powder E, 42.3 g of powder F, 37.2 g of alumina sol and 900 g of water were charged into a magnetic ball mill, mixed and pulverized to obtain a slurry liquid. Got This slurry liquid was attached to a cordierite-based monolith carrier (1.2 L, 900 cells), excess slurry in the cells was removed by an air stream, and the mixture was dried at 130 ° C and then calcined at 400 ° C for 1 hour to obtain a catalyst. A catalyst having a component part of 300 g / L was obtained. On this catalyst component part, 183.6 g of powder G, 431.6 g of powder D, 63.5 g of powder F, 98.1 g of powder B, 78.2 g of activated alumina, 45 g of alumina sol, and 900 g of water were magnetized. The resulting mixture was put into a ball mill, and the slurry liquid obtained by mixing and pulverizing was adhered to the slurry, and the excess slurry in the cell was removed by an air stream and dried at 130 ° C., followed by calcination at 400 ° C. for 1 hour to obtain a catalyst component portion of 200 g / L catalyst was obtained. This catalyst was immersed in a mixed aqueous solution of cesium acetate and cerium acetate to impregnate the catalyst with cesium and cerium. The amount of cesium is Cs ₂ O
Is 50 g / L, and the amount of cerium is 10 g as CeO _2.
Was / L. The amount of Ce other than impregnation is 28.2 g /
It was L. The coating thickness ratio of this catalyst was 0.67, the amount ratio of the cerium compound was 1.2, and the amount ratio of the cesium compound was 0.45. Also, the Pt / Pd ratio is 3, Pd _U /
The Pd _L ratio was 1 and the (Pt + Pd) / Rh ratio was 12.

(Example 25) 44.4 g of powder E, 42.3 g of powder F, 768.3 g of activated alumina, 45 g of alumina sol and 900 g of water were charged into a magnetic ball mill and mixed and pulverized to obtain a slurry liquid. It was This slurry liquid was attached to a cordierite-based monolith carrier (1.2 L, 900 cells), excess slurry in the cells was removed by an air stream, and the mixture was dried at 130 ° C and then calcined at 400 ° C for 1 hour to obtain a catalyst. A catalyst having a component part of 300 g / L was obtained. On this catalyst component part, 33.3 g of powder D, 63.5 g of powder F, and powder B
48.6 g, activated alumina 709.6 g, alumina sol 45 g, and water 900 g into a magnetic ball mill,
After adhering the slurry liquid obtained by mixing and pulverizing, removing excess slurry in the cell with an air stream and drying at 130 ° C.,
The mixture was calcined at 400 ° C. for 1 hour to obtain a catalyst component portion of 200 g / L. This catalyst was immersed in a mixed aqueous solution of cesium acetate and cerium acetate to impregnate the catalyst with cesium and cerium. The amount of cesium was 50 g / L as Cs ₂ O, and the amount of cerium was 10 g / L as CeO ₂ . Moreover, the amount of Ce other than the impregnation was 28.2 g / L. The coating thickness ratio of this catalyst was 0.67, the amount ratio of the cerium compound was 1.2, and the amount ratio of the cesium compound was 0.43.

Comparative Example 1 Activated alumina having a specific top surface side product of 180 m ² was impregnated with a cerium nitrate solution, dried and then calcined in air at 400 ° C. for 1 hour to obtain a powder. C of this powder
The e concentration was 2.3%. This powder was impregnated with a dinitrodiamine platinum solution, dried and then baked in air at 400 ° C. for 1 hour to obtain a powder K. Pt concentration of this powder is 0.8%
Met. Activated alumina having a specific surface area of 180 m ² was impregnated with a cerium nitrate solution, dried and calcined in air at 400 ° C. for 1 hour to obtain a powder. The Ce concentration of this powder is 2.9.
%Met. This powder was impregnated with a dinitrodiamine platinum solution, dried and then baked in air at 400 ° C. for 1 hour to give powder L.
Got The Pt concentration of this powder was 0.4%. 724.5 g of powder L, 42.3 g of powder F, 88.2 g of activated alumina, 45 g of alumina sol and 900 g of water were put into a magnetic ball mill, and mixed and pulverized to obtain a slurry liquid.
This slurry liquid is used as a cordierite monolith carrier (1.2
L, 900 cells), remove excess slurry in the cells by air flow and dry at 130 ° C, then 400 ° C
It was calcined for 1 hour to obtain a catalyst of 300 g / L of catalyst component. On this catalyst component part, 543.6 g of powder K, 63.5 g of powder F, 212.4 g of powder B, 35.5 g of activated alumina, 45 g of alumina sol, and 900 g of water were charged into a magnetic ball mill, and mixed and ground. The slurry thus obtained was adhered, excess slurry in the cell was removed by an air stream, and the slurry was dried at 130 ° C. and then calcined at 400 ° C. for 1 hour to obtain a catalyst component part of 200 g / L catalyst. The cerium amount of this catalyst was 38.2 g / L as CeO ₂ . The catalyst was dipped in an aqueous solution of cesium acetate to impregnate the catalyst with cesium. The amount of cesium was 50 g / L as Cs ₂ O. The coating thickness ratio of this catalyst was 0.67, the amount ratio of the cerium compound was 0.8, and the amount ratio of the cesium compound was 0.4.
It was 3.

(Comparative Example 2) Specific upper surface side product is 180 m^TwoLive
-Impregnated alumina with cesium acetate solution and dried in air
The powder was obtained by firing at 400 ° C. for 1 hour. C of this powder
The s concentration was 24.8%. Dinitrodia in this powder
Impregnate with minplatinum solution and dry for 1 hour at 400 ℃ in air
Calcination gave powder O. The Pt concentration of this powder is 0.8
%Met. Specific surface side product is 180m^TwoOf activated alumina
Impregnate with cesium acetate solution, dry, and air at 400 ℃ for 1
It was calcined for a time to obtain a powder. The Cs concentration of this powder is 8.
It was 3%. Dinitrodiamine platinum solution to this powder
Impregnate and dry, then burn in air at 400 ° C for 1 hour to obtain powder
P was obtained. The Pt concentration of this powder was 0.4%. powder
724.5g powder P, 42.3g powder F, activated aluminum
88.2g of water, 45g of alumina sol, 900g of water
Put into a magnetic ball mill, mix and grind to obtain a slurry liquid.
It was This slurry liquid is used as a cordierite monolith carrier.
(1.2 L, 900 cells), and attach the cells by air flow
After removing the excess slurry inside and drying at 130 ℃,
Baking at 400 ℃ for 1 hour, touch the catalyst component part 300g / L
I got a medium. On this catalyst component part, powder O was added to 543.6.
g, powder F 63.5 g, powder B 212.4 g, activity
Alumina 35.5 g, alumina sol 45 g, water 90
Slurry obtained by putting 0 g into a magnetic ball mill and mixing and pulverizing
Liquid and attach excess liquid in the cell by air flow.
Removed and dried at 130 ° C, then baked at 400 ° C for 1 hour
Then, a catalyst having a catalyst component portion of 200 g / L was obtained. Of this catalyst
Cs amount is Cs_TwoIt was 50 g / L as O. this
Immerse the catalyst in an aqueous cerium acetate solution and
Impregnated with aluminum. CeO is CeO _TwoAs 10g / L
Met. The amount of Ce other than impregnation is 28.2 g / L.
there were. The coating thickness ratio of this catalyst was 0.67.
The amount ratio of the aluminum compound is 1.2, and the amount ratio of the cesium compound is 1.
It was 3.

<Evaluation test> (Durability method) A catalyst was attached to the exhaust system of an engine with a displacement of 4400 cc, and domestic regular gasoline (S = 10 pp
m or less), the catalyst inlet temperature is 700 ° C., and
I drove for hours.

(S poisoning endurance) A catalyst was attached to the exhaust system of an engine with a displacement of 2000 cc and gasoline mixed with S (S = 3
00 ppm), the catalyst inlet temperature is 400 ° C.,
I ran for 5 hours. At this time, the lean (A / F = 25) running for 1 minute and the rich running (A / F = 11.0) for 2 seconds were repeated.

(S poison removal) A catalyst was installed in the exhaust system of an engine with a displacement of 2000 cc, domestic regular gasoline (S = 10 ppm or less) was used, and the catalyst inlet temperature was 70
It was operated at 0 ° C. and A / F = 14.2 for 10 minutes.

(Evaluation method) A catalyst was attached to the exhaust system of an engine having a displacement of 2000 cc, and after running for 50 hours at 700 ° C., the 10-15 mode was run at two points after the release of S poisoning. The conversion rate was calculated. In the mode, lean (A / F = 25) during steady running, fuel cut during deceleration,
During acceleration, the operation was rich (A / F = 11.0, seconds) → stoichiometric (A / F = 14.3). The catalyst inlet temperature was 400 ° C. The results are shown in Table 2.
Further, the same evaluation was carried out by disposing a three-way catalyst before the catalyst of the present invention. The results are shown in Table 3.

[0075]

[Table 1]

[0076]

[Table 2]

[0077]

[Table 3]

From Tables 1 to 3, the exhaust gas purifying catalysts obtained in Examples 1 to 25, which are within the preferred range of the present invention, are superior to the exhaust gas purifying catalysts obtained in Comparative Examples 1 and 2. It can be seen that it has excellent performance. In particular, the catalysts of the examples are excellent in NOx conversion performance before S poisoning and after S poisoning removal.

Although the present invention has been described in detail with reference to the preferred embodiments, the present invention is not limited to these embodiments, and various modifications can be made within the scope of the gist of the present invention. For example, the experiments of the examples were all carried out on a gasoline vehicle, but the same effect can be obtained with a diesel engine.

[0080]

As described above, according to the present invention, since the cerium compound and the cesium compound are contained in the vicinity of the catalyst component in a fixed arrangement, it is possible to adsorb, desorb and purify NOx, and particularly NOx. Has excellent adsorption performance of
It is possible to provide an exhaust gas purification catalyst that can suppress S poisoning and can easily remove S poisoning, a method for manufacturing the same, and an exhaust gas purification device.

[Brief description of drawings]

FIG. 1 is a graph showing the relationship between alkali species and NOx adsorption rate.

FIG. 2 is a diagram showing an outline of a coat layer structure.

FIG. 3 is a diagram showing an outline of a coat layer structure.

FIG. 4 is a graph showing the relationship between the Pt / Pd ratio and the NOx conversion rate.

FIG. 5 is a graph showing the relationship between the Pd _U / Pd _L ratio and the NOx conversion rate.

FIG. 6 is a view showing an X-ray diffraction peak of barium carbonate.

FIG. 7 is an EPMA image showing the impregnation state of Cs and Ce.

─────────────────────────────────────────────────── ─── Continued Front Page (51) Int.Cl. ⁷ Identification Code FI Theme Coat (reference) F01N 3/20 F01N 3/24 C 3/24 3/28 301E 3/28 301 B01D 53/36 104A 102H F term (reference) 3G091 AA17 AB03 AB06 AB09 BA11 BA14 GA18 GB05W GB06W GB07W GB17X HA10 4D048 AA06 AA13 AA18 AB05 AB07 BA01X BA14X BA15X BA19X BA30X BA31X BA33X BA41X BA45X BB02 BB16 CC32 CC46 EA04 4G069 AA03 AA08 BA01A BA01B BA13B BA21C BB02A BB02B BB04A BB04B BB16A BB16B BC06A BC06B BC06C BC10A BC10B BC13A BC13B BC43A BC43B BC43C BC71A BC71B BC72A BC72B BC75A BC75B BE08C CA03 CA09 EA19 EB12Y EB15X EB15Y EC29 EE06 EE09 FA02 FB19 FC02 FC08

Claims (18)

[Claims] 1. A porous carrier coated with a catalyst component part containing a cerium compound and a cesium compound, wherein the cerium compound is contained more on the upper surface side of the catalyst component part, and the cesium compound is contained in the catalyst component. The exhaust gas purifying catalyst is characterized in that it is contained more on the lower surface side of the portion. 2. The catalyst component part is composed of two or more catalyst layers, wherein the upper surface side of the catalyst layer has a higher content of the cerium compound, and the lower surface side of the catalyst layer has a higher content of the cesium compound. The exhaust gas purifying catalyst according to claim 1. 3. The catalyst component part satisfies the following formula 0.25 ≦ thickness of catalyst component part upper surface side / thickness of catalyst component part lower surface side ≦ 1. Exhaust gas purification catalyst described. 4. The cerium compound contained in the catalyst component part satisfies the following formula 1 ≦ Ce compound content on the upper surface side of the catalyst component part / Ce compound content on the lower surface side of the catalyst component part <2. The exhaust gas purifying catalyst according to any one of claims 1 to 3. 5. The cesium compound contained in the catalyst component part satisfies the following formula 0.1 ≦ Cs compound content on the upper surface side of the catalyst component part / Cs compound content on the lower surface side of the catalyst component part <1. The exhaust gas purifying catalyst according to any one of claims 1 to 4, which is characterized in that. 6. The catalyst component part comprises an upper catalyst layer and a lower catalyst layer, and satisfies the following formula: 0.25 ≦ thickness of upper catalyst layer / thickness of lower catalyst layer ≦ 1. Item 3. The exhaust gas purification catalyst according to Item 1 or 2. 7. The upper catalyst layer and the lower catalyst layer are represented by the following formula 1 ≦ Ce compound content of the upper catalyst layer / Ce of the lower catalyst layer:
The exhaust gas purifying catalyst according to claim 6, wherein the compound content ≤ 2 is satisfied. 8. The upper catalyst layer and the lower catalyst layer satisfy the following formula: 0.1 ≦ Cs compound content of upper catalyst layer / Cs compound content of lower catalyst layer <1. The exhaust gas purification catalyst according to 6 or 7. 9. The catalyst component portion contains rhodium and platinum and / or palladium.
The exhaust gas purifying catalyst according to any one of items 1 to 8. 10. The catalyst component upper surface side is at least one selected from the group consisting of rhodium, platinum and palladium.
Containing noble metal of the kind, the lower surface side of the catalyst component is platinum and / or
Alternatively, the exhaust gas purifying catalyst according to any one of claims 1 to 9, which contains palladium. 11. The ratio Pt / Pd between the platinum content and the palladium content in the catalyst component part is 1.1 to 4.2, and the palladium content (Pd _U ) on the upper surface side of the catalyst component part and the above. palladium content of the catalyst component portion lower surface (Pd _L) and the exhaust gas purifying catalyst according to claim 10 the ratio _Pd U / Pd _L is equal to or 0-1 of. 12. The exhaust gas purifying catalyst according to claim 9, wherein the total amount of the noble metal is 0.7 g or more and less than 5.7 g per 1 L of the catalyst. 13. The platinum content and the ratio of the palladium content to the rhodium content satisfy the following expression 3 ≦ (Pt + Pd) / Rh ≦ 10.
Exhaust gas purifying catalyst according to one section. 14. The catalyst component part according to claim 1, wherein the catalyst component part contains a Ba compound and / or a Mg compound, and the amount of these is larger on the upper surface side of the catalyst component part than on the lower surface side of the catalyst component part. The exhaust gas purifying catalyst according to any one of the items. 15. The Ba compound and the Mg compound are partly or wholly compounded to form a compound having the following general formula Ba _x Mg _y (CO ₃ ) ₂ (where x and y represent the atomic ratio of each element, and x = 0.
5 to 1.999, y = 0.001 to 1.5, x + y =
The exhaust gas purifying catalyst according to claim 14, which forms a complex carbonate represented by (2.0). 16. A method for producing the exhaust gas purifying catalyst according to claim 1, wherein a carrier is coated with a catalyst component to form a catalyst layer, and the catalyst layer is soluble in the catalyst layer. A mixed solution containing a cerium compound aqueous solution and a soluble cesium compound aqueous solution is dipped and impregnated, and at this time, a distribution state of the cerium compound and the cesium compound is adjusted to form a catalyst component part of an exhaust gas purifying catalyst. Production method. 17. The method for producing an exhaust gas purifying catalyst according to claim 16, wherein the cerium compound aqueous solution is a cerium acetate aqueous solution, and the cesium compound aqueous solution is a cesium acetate aqueous solution. 18. An exhaust gas purification apparatus using the exhaust gas purification catalyst according to any one of claims 1 to 15, wherein the three-way catalyst is provided from an upstream side of an exhaust passage of an internal combustion engine or a combustion apparatus. And an exhaust gas purifying device, wherein the exhaust gas purifying catalyst is sequentially arranged.