JP5022970B2 - Exhaust gas purification material and exhaust gas purification filter - Google Patents

Description

  The present invention relates to an exhaust gas purification material and an exhaust gas purification filter. More specifically, the present invention relates to particulate matter (hereinafter sometimes referred to as PM) discharged from diesel engines including automobile applications. The present invention relates to an exhaust gas purifying material for combustion removal, and an exhaust gas purifying filter for a diesel engine using the catalyst.

Various harmful substances are contained in the exhaust gas of the diesel engine which is a diesel engine. In recent years, nitrogen oxides (NO _x ) and PM have become a problem among the harmful substances. Among these, PM is a fine particle mainly composed of carbon. As a method for removing PM, a method of mechanically trapping PM by installing a diesel particulate filter (hereinafter referred to as DPF) in an exhaust gas flow path is becoming common. When the amount of PM trapped in the DPF becomes a predetermined amount or more, the PM is regenerated by removing the PM from the DPF by burning or gasifying intermittently or continuously.

This DPF regeneration process requires a temperature equal to or higher than the exhaust gas temperature. Therefore, (1) a method of burning PM by external heating using an electric heater, a burner, etc., (2) an oxidation catalyst is installed on the engine side from the DPF, and NO in the exhaust gas is converted into NO by the oxidation catalyst. oxidized to _2, the method of burning PM by oxidizing power of the NO _2, (3) DPF to coexist NOx storage catalyst, due to the air-fuel ratio fluctuation of the exhaust gas, the NOx absorption and desorption from the NOx storage catalyst A method of burning PM by the active oxygen generated at the time has been proposed.

  The external heating method using an electric heater, a burner, etc. described in the above (1) needs to prepare the heating system and heating energy separately, and there is a problem that the DPF regeneration system and the regeneration operation become complicated. It was.

In the method using an oxidation catalyst described in (2) above, it is difficult to maintain the activity of the oxidation catalyst because the exhaust gas temperature is low. For this reason, there has been a problem that, unless under certain operating conditions, NO is oxidized and NO ₂ in an amount necessary for PM combustion cannot be secured in the exhaust gas. Further, there will be a problem that NOx in the exhaust gas will be reduced due to stricter exhaust gas regulations for NOx and sufficient NO ₂ cannot be obtained.

  The method of coexisting the NOx storage catalyst described in the above (3) is such that the NOx storage catalyst is poisoned by sulfur contained in the exhaust gas, and the NOx storage and release ability is reduced, thereby reducing the PM combustion activity. There was a problem.

  Based on the above problems, DPF supports a catalyst that is durable against toxic substances such as sulfur, and lowers the combustion start temperature of PM by the action of the catalyst, at the current exhaust gas temperature. A method of continuously burning PM is considered.

  As a specific example of this method, Non-Patent Document 1 discloses a system in which a sulfur adsorbent and a catalyst are combined. The system uses an alkali metal element as a sulfur adsorbent, and the alkali metal element adsorbs a sulfur component in the exhaust gas and prevents sulfur from flowing to the catalyst.

Spec Publ Soc Auto Eng (2007), no. SP-2080, 85-91

  In the system combining the sulfur adsorbent and the catalyst, poisoning deterioration due to sulfur of the catalyst can be suppressed while sulfur is adsorbed on the adsorbent. However, when sulfur exceeding the adsorbable amount of the adsorbent flows, the sulfur is also adsorbed by the catalyst. As a result, the catalyst is poisoned with sulfur, the catalytic activity is reduced, and the PM combustion temperature may increase.

  The present invention has been made in view of such problems of the prior art, and the object of the present invention is to prevent the purification catalyst component from being poisoned by sulfur contained in diesel engine exhaust gas at a low temperature. An object is to provide an exhaust gas purifying material and an exhaust gas purifying filter capable of burning PM.

  As a result of intensive studies to solve the above problems, the present inventors have made a configuration in which the exhaust gas purifying material is a mixed system of the purifying catalyst component and the coexisting substance, and the sulfur content adhering to the catalyst component of the coexisting substance. The present inventors have found that the above problems can be solved by a configuration in which the affinity for the sulfur-containing acidic gas is made higher than the affinity of the purification catalyst component, and the present invention has been completed.

That is, the first invention for solving the above-described problem is
An exhaust gas purifying material for lowering the combustion temperature of particulate matter mainly composed of carbon contained in exhaust gas of a diesel engine,
A purification catalyst component having a catalytic action to lower the combustion temperature of the particulate matter;
A coexisting substance which is a composite oxide containing at least one of an alkali metal and an alkaline earth metal that recovers the catalytic action reduced by poisoning of the sulfur-containing acidic gas, and at least one of an acidic element and an amphoteric element ;
See containing at least one kind of an element <br/> selected from platinum group elements,
The coexisting substance is
If the temperature rises above 500 ° C,
Restoring the catalytic action under one or both of the conditions where the concentration of the carbon monoxide component is 100 ppm or more or the concentration of the hydrocarbon component is 200 ppm or more;
The coexisting substance is contained in an amount of 5 to 50% by mass of the entire exhaust gas purification material,
The exhaust gas purification material has a specific surface area of 10 m ² / g or more and 100 m ² / g or less by the BET method .

The second invention is
An exhaust gas purification filter using the exhaust gas purification material.

The second aspect of the second invention is:
In addition to the exhaust gas purification material, an exhaust gas purification filter comprising an exhaust gas purification material comprising at least one element selected from platinum group elements.

  According to the present invention, since the purifying catalyst component and the coexisting substance are used, the sulfur-containing acidic gas can be preferentially adsorbed on the coexisting substance, and the sulfur-containing acidic gas adsorbed on the purifying catalyst component can be further absorbed. Desorption can be promoted. As a result, the purification catalyst component is less susceptible to poisoning by sulfur contained in the exhaust gas of the diesel engine, and the rise in PM combustion temperature can be suppressed.

  The exhaust gas purification material according to the present invention has a purification catalyst component and a coexisting substance. The purification catalyst component is a catalyst component that lowers the combustion temperature of PM. On the other hand, the coexisting substance is a substance that can recover the catalytic action of the purified catalytic component whose catalytic action has been reduced by poisoning with the sulfur-containing acidic gas contained in the exhaust gas. More specifically, it is a substance that adsorbs the sulfur-containing acidic gas contained in the exhaust gas more than the purification catalyst component.

  Further, the coexisting substance is the adsorbed sulfur-containing material at a timing when either or both of the carbon monoxide and hydrocarbon components in the exhaust gas are increased when the exhaust gas temperature is increased. It is a substance that can realize either or both of desorbing acidic gas or promoting desorption of sulfur-containing acidic gas adsorbed on the catalyst.

  As described above, since the present fuel contains a small amount of sulfur on the order of ppm, it is inevitable that sulfur-containing acidic gas is contained in the exhaust gas of the diesel engine. For this reason, the exhaust gas purification material is constantly exposed to sulfur-containing acidic gas, and the purification catalyst component contained in the exhaust gas purification material is also exposed to the sulfur-containing acidic gas, resulting in sulfur poisoning and reduced catalyst activity. End up. As a result, the combustion temperature of PM rises and PM stays in the DPF.

  However, in the exhaust gas purification material according to the present invention, the coexisting substance coexisting with the purification catalyst component has a higher affinity for the sulfur-containing acidic gas than the purification catalyst component. Because of this high affinity, coexisting substances adsorb sulfur-containing acidic gas in diesel engine exhaust gas prior to the purification catalyst component, so that poisoning of the purification catalyst component is greatly suppressed, preventing a decrease in catalytic action. be able to. Thereby, the combustion temperature of the particulate matter in the exhaust gas can be continuously reduced.

  Next, when the exhaust gas temperature rises, the concentration of carbon monoxide and hydrocarbon components in the exhaust gas rises, and when these rises occur simultaneously, the coexisting substances desorb the sulfur-containing acidic gas adsorbed on itself. Simultaneously, the sulfur-containing acidic gas adsorbed on the purification catalyst component is also released. Therefore, the catalytic action of the purification catalyst component can be recovered.

  Examples of the “sulfur-containing acid gas” include thiophenes, benzothiophenes, dibenzothiophenes, thiols such as t-butyl mercaptan, thioethers such as dimethyl sulfide, and carbonyl sulfide (COS). Moreover, the gas derived from difficult desulfurization compounds, such as 4-methyl dibenzothiophene (MDBT) and 4, 6- dimethyl dibenzothiophene (DMDBT) which exist in diesel fuel, is also included.

  Throughout the present specification and claims, the ability of the purification catalyst component to lower the combustion temperature of PM is referred to as catalytic action or catalytic activity.

  Hereinafter, the best mode for carrying out the invention will be described. 1. Regarding the material structure of the exhaust gas purifying material according to the present invention. 2. About the purification catalyst component and the coexisting substance in the exhaust gas purification material according to the present invention; 3. Regarding the action of the exhaust gas purifying material according to the present invention; 4. a method for producing a purification catalyst component and a coexisting substance according to the present invention; The purification catalyst component and the coexisting substance evaluation method according to the present invention will be described in detail in this order.

1. About the material structure of the exhaust gas purifying material according to the present invention [coexisting substances]
The coexisting substance used in combination with the purification catalyst component can be typically composed of a composite oxide containing at least one of an alkali metal and an alkaline earth metal and at least one of an acidic element and an amphoteric element.

  Here, it is preferable to use one or both of potassium and cesium as the alkali metal. As the alkaline earth metal element, it is preferable to use barium, strontium, calcium or magnesium, and any combination thereof, and more preferably one of strontium and barium, or a mixture thereof.

  On the other hand, bismuth is preferably used as the acidic element. Further, as the amphoteric element, it is preferable to use titanium, zirconium, aluminum, gallium, indium or tin, and those related to any combination thereof, and more preferably one of zirconium and aluminum or a mixture thereof. .

In addition, at least one of alkali metal and alkaline earth metal constituting the coexisting substance (this is described as A element) and at least one of an acidic element and amphoteric element (this is described as B element). It is preferable that a composite oxide represented by the general formula: A _(1-x) B _x O _δ is formed.

  As for x which shows the molar ratio of an alkali, alkaline-earth metal element, an acidic element, or an amphoteric element, 0 <x <= 0.9 is preferable and it is more preferable that it is 0 <x <= 0.8. δ is an arbitrary number (0 <δ <10) suitable for various composite oxides.

  When the coexisting substance is, for example, an oxide of an alkali metal or alkaline earth metal, the affinity of the oxide for the sulfur-containing acidic gas is strong. As a result, once the sulfur-containing acidic gas is adsorbed, its adsorption binding force is strong, and it becomes difficult to desorb the sulfur-containing acidic gas. Under such circumstances, if a sulfur-containing acidic gas that exceeds the adsorbable capacity flows, there is a concern that the adsorption capacity of the sulfur-containing acidic gas is greatly reduced. On the other hand, when the B element is present (0 <x), even if the sulfur-containing acidic gas is once adsorbed to the oxide, the sulfur-containing acidic gas can be easily desorbed.

  On the other hand, due to the presence of B element, the affinity of the coexisting substance with the sulfur-containing acidic gas tends to be weakened. Therefore, when the ratio of the B element is excessive, the coexisting substance does not adsorb the sulfur-containing acidic gas. Therefore, the abundance ratio of the B element is preferably x ≦ 0.9. If the ratio of the B element is this condition, the coexisting substance has the ability to adsorb sulfur-containing oxidizing gas, and can also desorb the adsorbed sulfur-containing acidic gas. That is, when 0 <x ≦ 0.9, the affinity of the coexisting substance for the sulfur-containing acid gas becomes appropriate.

  Further, among the combinations of elements constituting the coexisting substance, when the A element is Ba and the B element is Bi, when the A element is Sr and the B element is Bi, when the A element is Sr and the B element is Zr, In particular, it has been found that the affinity of the coexisting substance for the sulfur-containing acid gas is moderate.

  As a result, the coexisting substance generates an appropriate binding force due to an appropriate affinity with the sulfur-containing acid gas. Due to this moderate binding force, the sulfur-containing acidic gas adsorbed on the coexisting substances can be used when the exhaust gas temperature rises, when the concentrations of carbon monoxide and hydrocarbon components in the exhaust gas rise, and when these increases occur simultaneously. , Desorption from the coexisting substance becomes possible.

[Purification catalyst component]
The purification catalyst component is preferably an oxide having any crystal structure selected from perovskite, spinel, corundum, and fluorite.

  When using an oxide catalyst to lower the combustion temperature of PM emitted from a diesel engine, the oxide catalyst releases oxygen contained in its own crystals, and the released oxygen is considered to burn PM. It is done. In many cases, an oxide catalyst that exhibits a catalytic action by such a mechanism is caused by the crystal structure of the ability of the catalyst.

  Among the crystal structures described above, a fluorite structure is used, and an oxide mainly containing cerium is particularly preferable. It is generally known that cerium oxide is a substance with excellent oxygen absorption / release capacity used for three-way catalysts, and it is not in the stoichiometric ratio of the oxidizing and reducing components of the exhaust gas composition. , Occlude or release oxygen. When an element having a valence different from that of cerium is substituted, the oxygen storage / release capacity increases. Therefore, cerium oxide substituted with one or more elements is more preferable as the purification catalyst component.

2. About the purification catalyst component and the coexisting substance in the exhaust gas purification material according to the present invention [abundance ratio of the purification catalyst component and the coexisting substance]
The ratio of the coexisting substances in the exhaust gas purification material is effective in the range of 5 to 50% by mass, more preferably 5 to 40% by mass.

  When the ratio of the coexisting substances is 5% by mass or more, poisoning of the purification catalyst component by the sulfur-containing acidic gas can be suppressed. Furthermore, avoid the situation where the allowable range of sulfur-containing acidic gas adsorbed by coexisting substances is exceeded before the exhaust gas temperature rises and the concentration of carbon monoxide and hydrocarbon components in the exhaust gas rises. Can do.

  On the other hand, if the ratio of the coexisting substances is 50% by mass or less, the ratio of the purification catalyst component in the exhaust gas purification material can be secured, so that the catalytic activity for sufficiently burning PM can be obtained. However, the ratio of the coexisting substances in the exhaust gas purification material may depend on the exhaust system and configuration used, and is not limited to this.

[Coexistence of purification catalyst components and coexisting substances]
As the coexistence form of the purification catalyst component and the coexisting substance in the exhaust gas purification material, the following forms can be preferably applied.
(1) The purification catalyst component and the coexisting substance are pulverized and mixed so that the two powders are adjacent to each other. At this time, the two powders are not combined, and there may be a gap between the two powders.
(2) A coexisting substance is supported on the purification catalyst component.
(3) The purification catalyst component is supported on the coexisting substance.
(4) When the DPF is coated with the purification catalyst component and the coexisting substance, a mixed slurry of the purification catalyst component and the coexisting substance is coated.
(5) When the purification catalyst component and the coexisting substance are coated on the DPF, the purification catalyst component is first coated, and then the coexistence substance is coated.
(6) When the purification catalyst component and the coexisting substance are coated on the DPF, the coexistence substance is first coated, and then the purification catalyst component is coated.

[Characteristics of mixed powder of purification components and coexisting substances]
As a mixed powder characteristic of the purification catalyst component and the coexisting substance in the exhaust gas purification material, the specific surface area by the BET method is preferably 10 to 100 m ² / g. If the specific surface area is less than 10 m ² / g, the catalyst activity tends to be low, and if it exceeds 100 m ² / g, the catalyst activity tends to decrease due to thermal degradation due to temperature rise during regeneration. The particle size distribution preferably has a D50 diameter of 0.01 to 10 μm as measured by particle size distribution by a laser diffraction method. If the D50 diameter is less than 0.01 μm, a large amount of mixed powder is required to ensure the amount that penetrates into the DPF and develops the catalytic activity on the surface of the DPF, which is not preferable in terms of cost. If it exceeds 10 μm, the pores of the DPF are blocked and the pressure loss increases, which is not preferable.

[Other forms of coexistence of purification catalyst components and coexisting substances]
It is also preferable that the exhaust gas purification material composed of the purification catalyst component and the coexisting substance further contains a platinum group element. The platinum group element may be platinum, rhodium or palladium, and any combination thereof.

  It is also considered that the platinum group element contained in the purification catalyst component serves to assist the desorption when the sulfur-containing acidic gas is desorbed from the purification catalyst component. Therefore, it is preferably supported in a highly dispersed state with the purification catalyst component and coexisting substances. When the DPF is coated with a purification catalyst component or a coexisting substance, it may be supported on a carrier having a high specific surface area such as alumina. There is no restriction | limiting in particular in the support method of a platinum group element. Specifically, evaporation to dryness, impregnation and the like can be suitably applied.

3. Regarding the action of the exhaust gas purification material according to the present invention When the sulfur-containing acid gas is contained in the exhaust gas passing through the exhaust gas purification material composed of the purification catalyst component and the coexisting material described above, the sulfur-containing acid gas is , It is selectively adsorbed by the coexisting substance due to the affinity between the coexisting substance and the sulfur-containing acid gas. However, when the sulfur-containing acidic gas passes only through the coexisting substance, the coexisting substance has a low oxidizing power with respect to the sulfur-containing acidic gas, and thus the adsorption rate is low. However, since the purification catalyst component mixed with the coexisting substance has a high oxidizing power against the sulfur-containing acidic gas, the sulfur-containing acidic gas is easily oxidized and easily adsorbed on the coexisting substance. In the exhaust gas purification material, the sulfur-containing acidic gas is selectively adsorbed by the coexisting substance. As a result, poisoning of the purification catalyst component by the sulfur-containing acidic gas is greatly suppressed.

  In normal operation, the exhaust gas temperature of a diesel engine is as low as 200 ° C. or lower, but the temperature may be periodically raised by system control for various purposes. One of them is intended to regenerate the DPF. Fuel is injected into the engine side of the oxidation catalyst installed in the front stage of the DPF, and the exhaust gas temperature is increased by burning the fuel with the oxidation catalyst. The temperature of the exhaust gas to be introduced is raised, and the PM deposited on the DPF is burned.

  As another control, in a system in which a NOx storage catalyst is used in combination, the exhaust gas temperature periodically rises during regeneration of the NOx storage catalyst such as NOx release from the NOx storage catalyst. These exhaust gas increases occur by injecting fuel into the exhaust gas and combusting the fuel, so that the ratio of carbon monoxide and hydrocarbons in the exhaust gas is higher than in normal operation.

  The exhaust gas temperature rises and / or the concentration of carbon monoxide and hydrocarbon components in the exhaust gas increases due to the operation mode or system control of the diesel engine for the purpose of the DPF regeneration described above. The adsorbed sulfur-containing acidic gas can be desorbed. In addition, the coexisting substance promotes the desorption of the sulfur-containing acidic gas adsorbed on the purification catalyst component under the condition of desorbing the sulfur-containing acidic gas. Can be maintained over a long period of time.

  As a more preferable condition that the sulfur-containing acidic gas is desorbed, the temperature may be 500 ° C. or higher. This is because if the temperature is 500 ° C. or higher, the sulfur-containing acidic gas and sulfur in the gas are also desorbed, and it is possible to avoid that their adsorption or adsorption bonding becomes stronger. Further, the exhaust gas composition is preferably one or both of 100 ppm for carbon monoxide and 200 ppm or more for the hydrocarbon component.

  There are various hydrocarbon components in the exhaust gas such as propylene, but there is no particular limitation. Since the sulfur-containing acidic gas adsorbed on the coexisting substance or the purification catalyst component releases and desorbs oxygen, it is preferable that a reducing gas of carbon monoxide and hydrocarbon is present in order to efficiently recover the released oxygen. . In the presence of hydrogen that generates a strong reducing power, sulfur-containing acidic gas tends to be more easily desorbed, but the ratio of hydrogen contained in the exhaust gas varies greatly depending on the operating conditions of the diesel engine. Absent.

  The DPF using the exhaust gas purifying material according to the present invention preferably further includes a platinum group element. The platinum group elements preferably include those related to platinum, rhodium or palladium, and any combination thereof.

  As described above, when regenerating the DPF or the NOx storage catalyst, the fuel is injected into the exhaust gas to burn the fuel, so the ratio of carbon monoxide and hydrocarbons in the exhaust gas compared to normal operation. Becomes higher. Further, when PM is burned by the purification catalyst component, carbon monoxide may be generated due to incomplete combustion. This is because platinum group elements are effective for purifying these carbon monoxide and hydrocarbons.

  The platinum group element may be present at any position on the engine side from the DPF, on the DPF, and on the air release side from the DPF, but preferably on the DPF and on the air release side from the DPF. Further, since the platinum group element is required to purify carbon monoxide and hydrocarbon gas, it is preferably supported in a highly dispersed state. The supporting method in the highly dispersed state may be a general method such as evaporation to dryness or impregnation, and the supporting method is not particularly limited.

4). Purifying catalyst component and coexisting substance production method according to the present invention The purifying catalyst component and coexisting substance according to the present invention are, for example, a common coprecipitation method, an organic complex method, an amorphous precursor, and a solid phase method. It can be manufactured by a manufacturing method or the like.

  The purification catalyst component and the coexisting substance can be produced by the same production method except that the mixing of raw materials is changed. Therefore, the purification catalyst component and the method for producing the coexisting substance according to the present invention will be described below by taking the production of the coexisting substance as an example.

[Co-precipitation method]
The coprecipitation method prepares a salt of an element selected from the above alkali and alkaline earth metals and a salt of an element selected from an acidic element and an amphoteric element, and is suitable for producing a predetermined composite oxide. A raw salt aqueous solution containing these elements is prepared in a stoichiometric ratio.

  The salt of each element is not particularly limited. For example, inorganic salts such as sulfate, nitrate, phosphate, and chloride, and organic acid salts such as acetate and oxalate can be used. Of these, acetates and nitrates can be preferably used.

  This raw salt aqueous solution and a neutralizing agent are mixed to coprecipitate a salt containing the above elements. At this time, the neutralizing agent is not particularly limited, and for example, inorganic bases such as ammonia, caustic soda and caustic potash, and organic bases such as triethylamine and pyridine can be used. Moreover, the addition amount of a neutralizing agent is good to add and mix so that the pH of the slurry produced | generated after adding the neutralizing agent may be 6-14. A coprecipitate can be obtained by adjusting to the said pH range.

  The obtained coprecipitate is washed with water as necessary. Next, the obtained coprecipitate is dried by, for example, vacuum drying or ventilation drying. Then, the dried coprecipitate is heat-treated at 600 to 1200 ° C., preferably 800 to 1000 ° C. for 2 to 10 hours, whereby a desired composite oxide of coexisting substances can be obtained.

  At the time of the heat treatment, the atmosphere is not particularly limited as long as it is in a range in which a complex oxide of coexisting substances is generated. For example, air, nitrogen, argon, hydrogen, and an atmosphere in which water vapor is combined with each of these atmospheres can be used. From the viewpoint of production cost, air, nitrogen, and an atmosphere obtained by combining water vapor with these atmospheres are preferable.

[Organic complex method]
In the organic complex method, a salt of an element selected from the above-mentioned alkali and alkaline earth metals, an acidic element, and an amphoteric element are selected so that a stoichiometric ratio suitable for forming a predetermined composite oxide is obtained. A raw material organic complex aqueous solution is prepared from an element salt and a salt forming an organic complex such as citric acid, malic acid, or sodium ethylenediaminetetraacetate.

  As the salt of each element, the same salt as in the coprecipitation method can be used. The raw salt aqueous solution is prepared by mixing the raw salt of each element in the desired stoichiometric ratio and dissolving it in water. It can be prepared by mixing with an aqueous solution of the salt that forms. In addition, it is preferable that the mixture ratio of the salt which forms an organic complex is about 1.2-3 mol with respect to 1 mol of complex oxides and purification catalyst components of the coexisting substance obtained.

  This raw material aqueous solution is dried. The heating temperature at the time of drying is not particularly limited as long as the organic complex does not decompose, and is, for example, about room temperature to 150 ° C., preferably room temperature to 110 ° C., and can quickly remove moisture. I need it. Thereby, the above-mentioned organic complex is obtained.

  After forming an organic complex of each of the elements described above, temporary firing is performed. Pre-baking may be performed, for example, by heating at 250 ° C. or higher in a vacuum or an inert gas atmosphere.

  The obtained organic complex after calcination is heat-treated. By performing the heat treatment at, for example, 600 to 1000 ° C., preferably 600 to 950 ° C. for 2 to 10 hours, a target composite oxide of coexisting substances can be obtained. The atmosphere at the time of the heat treatment is not particularly limited as long as it is in a range in which a composite oxide of coexisting substances and a purification catalyst component are generated. For example, air, nitrogen, argon, hydrogen, and an atmosphere in which water vapor is combined with each of these atmospheres can be used. From the viewpoint of production cost, air, nitrogen, and an atmosphere obtained by combining water vapor with these atmospheres are preferable.

[Production method using amorphous precursor]
In the production method using an amorphous precursor, a powdery amorphous material containing an element selected from the above-mentioned alkali and alkaline earth metals at a stoichiometric ratio suitable for forming a composite oxide of coexisting substances is used. And a precursor material made of a powdery amorphous material containing an element selected from an acidic element and an amphoteric element.

A method for producing the amorphous precursor will be described.
First, a raw salt aqueous solution containing the above-described salts of both elements in a stoichiometric ratio suitable for forming a composite oxide of coexisting substances is prepared. Then, the raw salt aqueous solution and a precipitating agent such as carbonate containing alkali carbonate or ammonium ion are reacted at a temperature of 60 ° C. or lower and pH 6 or higher to generate a precipitate. The produced precipitate can be filtered and dried.

  More specifically, first, water-soluble mineral salts such as nitrates, sulfates, and chlorides of both elements described above are prepared. Then, an aqueous solution prepared by adjusting the molar ratio to be a raw salt aqueous solution containing a stoichiometric ratio suitable for generating a complex oxide of coexisting substances is prepared. The upper limit of the ion concentration of the constituent elements in the aqueous solution is determined by the solubility of the salts used. That is, it is preferable that the constituent element crystalline compound is not deposited. Usually, the total ion concentration of each of the above elements may be in the range of about 0.01 to 0.60 mol / L, but may exceed 0.60 mol / L.

  In order to obtain an amorphous precipitate from the aqueous solution, it is preferable to use a precipitating agent made of carbonate containing alkali carbonate or ammonium ion. Specific examples of the precipitant include sodium carbonate, sodium hydrogen carbonate, ammonium carbonate, ammonium hydrogen carbonate and the like. Moreover, it is also possible to add bases, such as sodium hydroxide and ammonia, as needed. Further, when a precipitate is formed by adding sodium hydroxide, ammonia, etc., an amorphous material suitable for the precursor material of the complex oxide used in the present invention can be obtained by blowing carbon dioxide into the aqueous solution. Can be obtained.

  When obtaining an amorphous precipitate, the pH of the aqueous solution is preferably controlled in the range of 6-11. This is because, in the region where the pH is 6 or more, rare earth elements form a precipitate, which is preferable. On the other hand, if the pH is 11 or less, crystalline precipitate formation can be avoided. Moreover, the production | generation of the crystalline compound particle | grains of a structural element can be avoided by making reaction temperature 60 degrees C or less.

  The obtained amorphous precursor is washed with water as necessary. Then, the obtained amorphous precursor is dried by, for example, vacuum drying or ventilation drying.

  By subjecting the dried amorphous precursor to a heat treatment of, for example, 500 to 1000 ° C., preferably 600 to 900 ° C. for 2 to 10 hours, a composite oxide or purification catalyst component of the desired coexisting substance can be obtained. it can. The atmosphere at the time of the heat treatment is not particularly limited as long as it is in a range in which a composite oxide of coexisting substances and a purification catalyst component are generated. For example, air, nitrogen, argon, hydrogen, and an atmosphere in which water vapor is combined with each of these atmospheres can be used. From the viewpoint of production cost, air, nitrogen, and an atmosphere obtained by combining water vapor with these atmospheres are preferable.

[Solid phase method]
In the solid-phase method, a salt of an element selected from the above-mentioned alkali and alkaline earth metal and a salt of an element selected from an acidic element and an amphoteric element are prepared, and a chemistry suitable for producing a predetermined composite oxide. These raw material salts are mixed in a stoichiometric ratio using a mixer such as a mortar.

  There are various kinds of raw material salts such as nitrates, carbonates, oxides, acetates, etc., but there is no particular limitation as long as the target coexisting substance complex oxide crystals are produced by the heat treatment described later. .

  By subjecting the mixture to a heat treatment of, for example, 500 ° C. to 1000 ° C., preferably 700 ° C. to 1000 ° C. for 2 to 30 hours, a desired composite oxide of coexisting substances can be obtained.

  The atmosphere at the time of the heat treatment is not particularly limited as long as it is in a range in which a composite oxide of coexisting substances and a purification catalyst component are generated. For example, air, nitrogen, argon, hydrogen, and an atmosphere in which water vapor is combined with each of these atmospheres can be used. From the viewpoint of production cost, air, nitrogen, and an atmosphere obtained by combining water vapor with these atmospheres are preferable.

5. Purification catalyst component and coexisting substance evaluation method according to the present invention Representative purification catalyst component and coexisting substance for evaluating the affinity for acid gas, crystal structure, durability against sulfur poisoning, and PM combustion performance The evaluation method will be described.

  The same evaluation method can be applied to the purification catalyst component and the coexisting substance. Thus, hereinafter, the method for evaluating an exhaust gas purifying material according to the present invention will be described by taking the evaluation of coexisting substances as an example.

[Affinity for acid gas]
The coexisting substance and Pt alumina (Pt 1 mass%) are weighed so as to have a mass ratio of 1: 1, and mixed in a mortar for 30 minutes. The mixed sample is compression-molded at 100 kg / cm ² by a mold press and then pulverized to produce a granular sample having a particle size of 0.5 to 1.0 mm.

0.2 g of the granular sample is placed in a vertical tubular furnace. Then, under the processing conditions of 300 ° C. × 4 hours, NO concentration is 400 ppm, H ₂ O is 10%, and the remaining N ₂ gas is flowed at a total flow rate of 500 cc / min to adsorb NOx. Thereafter, the temperature is raised from 300 ° C. to 700 ° C. in a N ₂ atmosphere at a rate of 10 ° C./min for 40 minutes. At this time, the desorbed NOx concentration is measured every 10 seconds, and the amount of NOx (desorption area) obtained by integrating the measured values at 240 points of the NOx concentration is calculated.

[X-ray diffraction measurement]
The measurement is performed in the range of 2θ = 20 to 70 degrees. As measurement conditions, a Co tube is used as the tube, and the tube voltage is 40 kV and the tube current is 30 mA. As the X-ray diffractometer, X-ray diffractometer RINT-2100 manufactured by Rigaku Corporation or an equivalent of this apparatus can be used.

[Sulfur poisoning treatment]
The coexisting substance according to the present invention and the purification catalyst component are weighed so as to have a predetermined mixing ratio, and mixed in a mortar for 15 minutes to produce an exhaust gas purification material. The exhaust gas purification material is compressed and molded at 100 kg / cm ² by a die press, and then pulverized to produce a granular sample having a particle size of 1.0 to 2.0 mm.

A granular sample (3 g) is placed in a vertical tubular furnace. Then, under the processing conditions of 300 ° C. × 10 hours, sulfur poisoning treatment is performed by flowing an SO ₂ concentration of 200 ppm, O ₂ 10%, H ₂ O 10%, and the remaining N ₂ gas at a total flow rate of 500 cc / min.
Let the sample after the said sulfur poisoning process be a sample after sulfur treatment.

In order to desorb sulfur from the exhaust gas purifying material, the sulfur-treated sample is placed in a vertical tubular furnace. Then, under the processing conditions of 650 ° C. × 10 minutes, CO 0.9%, C ₃ H ₆ 375 ppm, CO ₂ 10%, H ₂ 0.3%, H ₂ O 10%, and the balance N ₂ gas at a total flow rate of 5 L / min. And carry out a reduction treatment. The sample after the reduction treatment is used as the sample after the reduction treatment.

The sample after reduction is placed in a muffle furnace. Then, oxidation treatment is performed in an air atmosphere under the treatment conditions of 650 ° C. × 10 minutes. Then, the obtained sample subjected to sulfur poisoning treatment, reduction treatment, and oxidation treatment is used as a regenerated sample. That is, by this sulfur poisoning treatment, three types of samples are obtained: a sample after sulfur treatment, a sample after reduction treatment, and a sample after regeneration.
In addition, the granular sample after each process is pulverized in a mortar.

[PM combustion temperature evaluation]
A sample before sulfur treatment, a sample after sulfur treatment, and a sample after regeneration prepared by the sulfur poisoning treatment evaluation are prepared. On the other hand, commercially available carbon black (manufactured by Mitsubishi Chemical Corporation) or an equivalent of this material is prepared as a simulated PM.

  Then, weigh the sample before sulfur treatment and carbon black so that the mass ratio is 6: 1 and mix for 20 minutes with an automatic mortar machine (AGA type manufactured by Ishikawa Factory) or an equivalent of this device. A mixed powder with carbon black is obtained. Similarly, a mixed powder of a sample after sulfur treatment and carbon black, and a mixed powder of a sample after regeneration and carbon black are also prepared.

  20 mg of the mixed powder is placed in a thermogravimetric / differential calorimetry (TG / DTA) apparatus, and the temperature is raised from 50 ° C. to 700 ° C. in the air at a heating rate of 10 ° C./min, and weight measurement is performed. Note that the thermogravimetric and differential thermal measurement (TG / DTA) equipment is Seiko Instruments Inc., TG / DTA6300 type) or an equivalent of this equipment. Let it be the combustion temperature.

Example 1
[Purification catalyst component synthesis]
A cerium nitrate solution having a concentration of 0.2 mol / L was prepared. The liquid temperature was adjusted to 25 ° C. while stirring the solution. When the liquid temperature reached 25 ° C., ammonium carbonate was added as a precipitant to the solution, and the aqueous solution was adjusted to pH = 8 to generate a precipitate. The produced precipitate was collected by filtration, washed with water, and dried at 125 ° C. to obtain a precursor powder. Next, the precursor powder was calcined by heat treatment at 800 ° C. for 2 hours in an air atmosphere to obtain a purification catalyst component containing CeO ₂ . The X-ray diffraction pattern of the obtained purification catalyst component is shown in FIG.

[Synthesis of coexisting substances]
Barium nitrate and bismuth nitrate are mixed so that the molar ratio of barium element to bismuth element is 0.5: 0.5, and water is added so that the total molar concentration in the solution is 0.2 mol / L. This was added to obtain a raw material solution. While stirring this solution, the temperature of the solution was adjusted to 25 ° C., and when the temperature reached 25 ° C., ammonium carbonate was added as a precipitating agent, and the pH was adjusted to 8 to produce a precipitate. The produced precipitate was collected by filtration, washed with water, and dried at 125 ° C. to obtain a precursor powder. Next, the precursor powder was baked by heat treatment at 800 ° C. for 5 hours in an air atmosphere to obtain a coexisting substance containing BaBiO ₃ . The X-ray diffraction pattern of the obtained coexisting substance is shown in FIG.

[Exhaust gas purification material synthesis]
The purification catalyst component and the coexisting substance were weighed so that the mass ratio of the purification catalyst component and the coexistence substance was 6: 4 and mixed in a mortar for 15 minutes to obtain an exhaust gas purification material.

  In addition, about the exhaust-gas purification material obtained in Examples 1-7, 12, the specific surface area was calculated | required by BET method. The measurement was carried out using 4 Saab US made by Your Sonics. Further, the volume-based particle size distribution was measured by a laser diffraction particle size distribution measuring method. The measurement used a Helos particle size distribution measuring device (HELOS & RODOS). These measurement results are shown in Table 1.

(Example 2)
[Purification catalyst component synthesis]
The same operation as in Example 1 was performed to obtain a purification catalyst component containing CeO _{2 according} to Example 2.

[Synthesis of coexisting substances]
A coexisting substance according to Example 2 was obtained by performing the same operation as in Example 1 except that the coexisting substance was replaced with a substance containing SrBi ₄ O ₇ from that containing BaBiO ₃ .

[Exhaust gas purification material synthesis]
The purification catalyst component and the coexisting substance were weighed so that the mass ratio of the purification catalyst component and the coexistence substance was 67:33 and mixed in a mortar for 15 minutes to obtain an exhaust gas purification material according to Example 2.

(Example 3)
[Purification catalyst component synthesis]
The same operation as in Example 1 was performed to obtain a purification catalyst component containing CeO _{2 according} to Example 3.

[Synthesis of coexisting substances]
A coexisting substance according to Example 3 was obtained by performing the same operation as in Example 1 except that the coexisting substance was replaced with a substance containing SrZrO ₃ from one containing BaBiO ₃ .

[Exhaust gas purification material synthesis]
The purification catalyst component and the coexisting substance were weighed so that the mass ratio of the purification catalyst component and the coexistence substance was 70:30, and mixed in a mortar for 15 minutes to obtain an exhaust gas purification material according to Example 3.

(Comparative Example 1)
[Purification catalyst component synthesis]
The same operation as in Example 1 was performed to obtain a purified catalyst component containing CeO _{2 according} to Comparative Example 1.

[Synthesis of coexisting substances]
Coexisting materials were not synthesized.

[Exhaust gas purification material synthesis]
Only the purification catalyst component was mixed in a mortar for 15 minutes to obtain an exhaust gas purification material according to Comparative Example 1.

(Comparative evaluation between Examples 1 to 3 and Comparative Example 1)
The relationship between Examples 1 to 3 and Comparative Example 1 will be described. In contrast to Comparative Example 1 consisting only of the purification catalyst component, Example 1 is one in which 40% by mass of a coexisting substance (BaBiO ₃ ) coexists with the purification catalyst component according to Comparative Example 1, and Example 2 33% by mass of a coexisting substance (SrBi ₄ O ₇ ) coexists with the purification catalyst component according to Comparative Example 1, and Example 3 has 30% by mass with respect to the purification catalyst component according to Comparative Example 1. A substance (SrZrO ₃ ) coexists.

  Here, from the evaluation results according to Examples 1 to 3 and Comparative Example 1, the purification catalyst component and the coexisting substances constituting the exhaust gas purification material according to Examples 1 to 3 obtained were evaluated. The said evaluation was performed in the PM combustion temperature evaluation of the sample obtained by affinity evaluation to acid gas, and the sulfur poisoning process.

[Affinity Evaluation for Acid Gas]
<Evaluation of Example 1>
When the exhaust gas purifying material according to Example 1 was configured, the compatibility with acidic gas was evaluated for the coexisting substances and the purifying catalyst component according to Comparative Example 1.

  In addition, the affinity evaluation with respect to the acidic gas with respect to the purification catalyst component which concerns on the comparative example 1 performed operation similar to the affinity evaluation with respect to the acidic gas with respect to a coexisting substance except having replaced the coexisting substance with the purification catalyst component.

  From the affinity evaluation result to the acid gas, the affinity of the purification catalyst component according to Comparative Example 1 to the acid gas and the affinity of the coexisting substance according to Example 1 to the acid gas are determined by the ratio of the desorption area. When used, the purification catalyst component: the coexisting substance = 1.0: 15.0. That is, it was found that the coexisting substance according to Example 1 can adsorb much more NOx than the purification catalyst component.

Moreover, the maximum point temperature in the desorption curve of the coexisting substance according to Example 1 was 13 ° C. higher than that of the purification catalyst component.
From the above results, it was found that the coexisting substance according to Example 1 has higher affinity for the acidic gas than the purification catalyst component.
The desorption curve is a curve obtained by taking temperature (time) on the horizontal axis and NOx concentration on the vertical axis.

<Evaluation of Example 2>
Evaluation of the affinity of the obtained exhaust gas purifying material according to Example 2 for acidic gas was performed in the same manner as in Example 1.

  From the results of the affinity evaluation to the acid gas, the affinity of the purification catalyst component according to Comparative Example 1 to the acid gas and the affinity of the coexisting substance according to Example 2 to the acid gas are determined by the ratio of the desorption area. When used, the purification catalyst component: the coexisting substance = 1.0: 10.1. That is, it was found that the coexisting substance according to Example 2 can adsorb much more NOx than the purification catalyst component.

Moreover, the maximum point temperature in the desorption curve of the coexisting substance according to Example 2 was 10 ° C. higher than that of the purification catalyst component.
From the above results, it was found that the coexisting substance according to Example 2 has higher affinity for acidic gas than the purification catalyst component.

[PM combustion temperature evaluation of samples obtained by sulfur poisoning]
<Evaluation of Example 1>
The PM combustion temperature evaluation of the sample obtained by the above-described sulfur poisoning treatment was performed on the exhaust gas purifying material according to Example 1 and Comparative Example 1. The evaluation results are shown in Table 1 and FIG. FIG. 3 is a bar graph in which the combustion temperature of carbon black is plotted on the vertical axis, the combustion temperature of the sample before sulfur treatment is hatched, the combustion temperature of the sample after sulfur treatment is plain, and the combustion temperature of the sample after regeneration is represented by a grid line. . The same applies to FIGS. 4 to 6 described later.

  From the evaluation results, the following became clear. That is, in the exhaust gas purifying material according to Example 1, the increase in the combustion temperature of carbon black after sulfur poisoning treatment is 22 ° C. due to the presence of the coexisting substances, which is significantly higher than the increase in the combustion temperature 162 ° C. in Comparative Example 1. Is suppressed.

  Compared with the purification catalyst component according to Example 1 and Comparative Example 1, the combustion temperature of the coexisting material carbon black according to Example 1 is higher by 50 ° C. or more than the purification catalyst component. Furthermore, the purification catalyst component in the exhaust gas purification material according to Example 1 is 60% by mass, and the purification catalyst component in the exhaust gas purification material according to Comparative Example 1 is 100% by mass. That is, although the purification catalyst component in the exhaust gas purification material according to Example 1 is less than the purification catalyst component in the exhaust gas purification material according to Comparative Example 1, the carbon black after sulfur treatment by mixing of coexisting substances The increase in the combustion temperature is greatly suppressed. This is considered to be the effect that the exhaust gas purifying material according to Example 1 has an effect that sulfur is selectively adsorbed by the coexisting substance due to the presence of the coexisting substance and the adsorption of sulfur to the purification catalyst component is suppressed.

  Further, in the exhaust gas purifying material according to Example 1, the combustion temperature of the carbon black after regeneration remains at an increase of 16 ° C. compared with that before the treatment, and regeneration is promoted by the presence of coexisting substances. I understand. On the other hand, since the exhaust gas purifying material according to Comparative Example 1 is composed only of the purifying catalyst component, the combustion temperature of the carbon black after regeneration is 63 ° C. higher than that before the treatment and is sufficiently regenerated. I understand that there is not.

  That is, it was found that the coexisting substance according to Example 1 has a great effect on both “suppression of deterioration after sulfur treatment” and “promotion of regeneration”.

  Here, “suppression of deterioration after sulfur treatment” is thought to be due to the affinity between the coexisting substances and the sulfur-containing acidic gas, but “regeneration promotion” has some effect in addition to the affinity. The mechanism itself is still unknown.

  Note that the presence of the coexisting substances has a great effect on both “suppression of deterioration after sulfur treatment” and “acceleration of regeneration” as in Examples 2 to 12 described later. Is still unknown.

<Evaluation of Example 2>
The PM combustion temperature evaluation of the sample obtained by the sulfur poisoning process described above was performed on the exhaust gas purifying materials according to Example 2 and Comparative Example 1. The evaluation results are shown in Table 1 and FIG. From the evaluation results, the following became clear. That is, in the exhaust gas purifying material according to Example 2, the increase in the combustion temperature of carbon black after sulfur poisoning treatment is 80 ° C. due to the presence of coexisting substances, which is significantly higher than the increase in the combustion temperature in Comparative Example 1. It is suppressed.

  The purification catalyst component in the exhaust gas purification material according to Example 2 is 67% by mass, and the purification catalyst component in the exhaust gas purification material according to Comparative Example 1 is 100% by mass. That is, although the purification catalyst component in the exhaust gas purification material according to Example 2 is less than the purification catalyst component in the exhaust gas purification material according to Comparative Example 1, the carbon black after sulfur treatment by mixing coexisting substances The increase in the combustion temperature is greatly suppressed. This is considered to be due to the effect that in the exhaust gas purifying material according to Example 2, sulfur is selectively adsorbed by the coexisting substance due to the coexistence of the coexisting substance, and the adsorption of sulfur to the purification catalyst component is suppressed.

Moreover, in the exhaust gas purifying material according to Example 2, the combustion temperature of the carbon black after regeneration is lowered by 4 ° C. compared with that before treatment, and it can be seen that regeneration is promoted by the presence of coexisting substances. .
That is, it was found that the coexisting substance according to Example 2 has a great effect on both “suppressing deterioration after sulfur treatment” and “promotion of regeneration”.

<Evaluation of Example 3>
The PM combustion temperature evaluation of the sample obtained by the sulfur poisoning process described above was performed on the exhaust gas purifying material according to Example 3 and Comparative Example 1. The evaluation results are shown in Table 1 and FIG. In FIG. 3, (1) before the treatment, (2) after the sulfur treatment, and (3) after the regeneration are shown on each bar graph (the same applies to the subsequent figures). From the evaluation results, the following became clear. That is, in the exhaust gas purifying material according to Example 3, the increase in the combustion temperature of carbon black after sulfur poisoning treatment is 49 ° C. due to the presence of coexisting substances, which is significantly higher than the increase in the combustion temperature in Comparative Example 1. It is suppressed.

  Compared to the purification catalyst component according to Example 3 and Comparative Example 1, the combustion temperature of the coexisting substance carbon black according to Example 3 is 120 ° C. or more higher than that of the purification catalyst component. Furthermore, the purification catalyst component in the exhaust gas purification material according to Example 3 is 70% by mass, and the purification catalyst component in the exhaust gas purification material according to Comparative Example 1 is 100% by mass. That is, although the purification catalyst component in the exhaust gas purification material according to Example 3 is less than the purification catalyst component in the exhaust gas purification material according to Comparative Example 1, the carbon black after sulfur treatment by mixing of coexisting substances The increase in the combustion temperature is greatly suppressed. This is considered to be due to the effect that in the exhaust gas purifying material according to Example 3, sulfur is selectively adsorbed by the coexisting substances due to the coexistence of the coexisting substances, and the adsorption of sulfur to the purification catalyst component is suppressed.

In addition, in the exhaust gas purifying material according to Example 3, the combustion temperature of the carbon black after regeneration remains only 17 ° C. higher than that before treatment, and regeneration is promoted by the presence of coexisting substances. I understand.
That is, it was found that the coexisting substance according to Example 3 has a great effect on both “suppressing deterioration after sulfur treatment” and “promotion of regeneration”.

Example 4
[Purification catalyst component synthesis]
A purification catalyst component according to Example 4 was obtained by performing the same operation as in Example 1 except that the purification catalyst component was replaced by Ce _0.9 Bi _0.1 O _{2 + δ} from CeO ₂ .

[Synthesis of coexisting substances]
The same operation as in Example 1 was performed to produce BaBiO ₃ , and a coexisting substance according to Example 4 was obtained.

[Exhaust gas purification material synthesis]
The purification catalyst component and the coexisting substance were weighed so that the mass ratio of the purification catalyst component and the coexistence substance was 70:30, and mixed in a mortar for 15 minutes to obtain an exhaust gas purification material according to Example 4.

(Comparative Example 2)
[Purification catalyst component synthesis]
The same operation as Comparative Example 1 was performed to obtain a purification catalyst component containing Ce _0.9 Bi _0.1 O _{2 + δ according} to Comparative Example 2.

[Synthesis of coexisting substances]
Coexisting materials were not synthesized.

[Exhaust gas purification material synthesis]
Only the purification catalyst component was mixed in a mortar for 15 minutes to obtain an exhaust gas purification material according to Comparative Example 2.

(Comparative evaluation between Example 4 and Comparative Example 2)
The relationship between Example 4 and Comparative Example 2 will be described. In contrast to Comparative Example 2 consisting only of the purification catalyst component, Example 4 is a case where 30% by mass of a coexisting substance (BaBiO ₃ ) coexists with the purification catalyst component according to Comparative Example 2.

  Here, from the evaluation results according to Example 4 and Comparative Example 2, the purification catalyst component and the coexisting substances constituting the exhaust gas purification material according to Example 4 were evaluated. The said evaluation was performed by the affinity combustion to acid gas and PM combustion temperature evaluation of the sample obtained by the sulfur poisoning process.

[Affinity Evaluation for Acid Gas]
The affinity for acid gas was evaluated for the coexisting substance according to Example 4 and the purification catalyst component according to Comparative Example 2.

As a result, the affinity of the acidic gas between the coexisting substance according to Example 4 and the purification catalyst component according to Comparative Example 2 is such that the ratio of the desorption area is the purification catalyst component: coexistence substance = 1.0: 14.6. Trip coexisting substance, was found to be capable of adsorbing a large amount of the NO _x in much.

  Further, since the temperature of the maximum point in the desorption curve of the coexisting substance is 110 ° C. higher than that of the purification catalyst component, it was found that the coexisting substance has a high affinity for acidic gas.

[PM combustion temperature evaluation of samples obtained by sulfur poisoning]
The exhaust gas purifying material according to Example 4 and Comparative Example 2 was evaluated for affinity to the above-described sulfur-containing acidic gas. The evaluation results are shown in Table 1 and FIG. From the evaluation results, the following became clear. That is, in the exhaust gas purifying material according to Example 4, the increase in the combustion temperature of carbon black after the sulfur poisoning treatment is 45 ° C. due to the presence of the coexisting substances, which is significantly higher than the increase in the combustion temperature of 154 ° C. in Comparative Example 2. Is suppressed.

  Compared with the purification catalyst component according to Example 4 and Comparative Example 2, the combustion temperature of the coexisting substance carbon black according to Example 4 is higher by 50 ° C. or more than the purification catalyst component. Furthermore, the purification catalyst component in the exhaust gas purification material according to Example 4 is 70% by mass, and the purification catalyst component in the exhaust gas purification material according to Comparative Example 2 is 100% by mass. That is, although the purification catalyst component in the exhaust gas purification material according to Example 4 is less than the purification catalyst component in the exhaust gas purification material according to Comparative Example 2, carbon black after sulfur treatment by mixing of coexisting substances The increase in the combustion temperature is greatly suppressed. This is considered to be due to the effect that in the exhaust gas purifying material according to Example 4, sulfur is selectively adsorbed by the coexisting substances due to the coexistence of the coexisting substances, and the adsorption of sulfur to the purifying catalyst component is suppressed.

  Further, in the exhaust gas purifying material according to Example 4, the combustion temperature of the carbon black after regeneration remains at an increase of 5 ° C. compared with that before treatment, and regeneration is promoted by the presence of coexisting substances. I understand. On the other hand, since the exhaust gas purifying material according to Comparative Example 2 is composed only of the purifying catalyst component, the combustion temperature of the carbon black after regeneration is 74 ° C. higher than that before the treatment and is sufficiently regenerated. I understand that there is not.

(Example 5)
[Purification catalyst component synthesis]
A purification catalyst component according to Example 5 was obtained by performing the same operation as in Example 1 except that the purification catalyst component was replaced with Ce _0.5 Bi _0.1 Pr _0.4 O _{2 + δ} from CeO ₂ .

[Synthesis of coexisting substances]
The same operation as in Example 1 was performed to produce BaBiO ₃ to obtain a coexisting substance according to Example 5.

[Exhaust gas purification material synthesis]
The purification catalyst component and the coexisting substance were weighed so that the mass ratio of the purification catalyst component and the coexistence substance was 70:30, and mixed in a mortar for 15 minutes to obtain an exhaust gas purification material according to Example 5.

(Example 6)
[Purification catalyst component synthesis]
A purification catalyst component according to Example 6 was obtained by performing the same operation as in Example 1 except that the purification catalyst component was replaced with Ce _0.5 Bi _0.1 Pr _0.4 O _{2 + δ} from CeO ₂ .

[Synthesis of coexisting substances]
SrBi ₄ O ₇ was produced in the same manner as in Example 1, and a coexisting substance according to Example 6 was obtained.

[Exhaust gas purification material synthesis]
The purification catalyst component and the coexisting substance were weighed so that the mass ratio of the purification catalyst component and the coexistence substance was 50:50 and mixed in a mortar for 15 minutes to obtain an exhaust gas purification material according to Example 6.

(Example 7)
[Purification catalyst component synthesis]
A purification catalyst component according to Example 7 was obtained by performing the same operation as in Example 1 except that the purification catalyst component was replaced with Ce _0.5 Bi _0.1 Pr _0.4 O _{2 + δ} from CeO ₂ .

[Synthesis of coexisting substances]
The same operation as in Example 1 was performed to produce Sr _0.3 Bi _0.7 O _δ , and a coexisting substance according to Example 7 was obtained.

[Exhaust gas purification material synthesis]
The purification catalyst component and the coexisting substance were weighed so that the mass ratio of the purification catalyst component and the coexistence substance was 60:40 and mixed in a mortar for 15 minutes to obtain an exhaust gas purification material according to Example 7.

(Example 8)
[Purification catalyst component synthesis]
A purification catalyst component according to Example 8 was obtained by performing the same operation as in Example 1 except that the purification catalyst component was replaced with Ce _0.5 Bi _0.1 Pr _0.4 O _{2 + δ} from CeO ₂ .

[Synthesis of coexisting substances]
BaZrO ₃ was produced in the same manner as in Example 1 to obtain a coexisting substance according to Example 8.

[Exhaust gas purification material synthesis]
The purification catalyst component and the coexisting substance were weighed so that the mass ratio of the purification catalyst component and the coexistence substance was 76:24, and mixed in a mortar for 15 minutes to obtain an exhaust gas purification material according to Example 8.

Example 9
[Purification catalyst component synthesis]
A purification catalyst component according to Example 9 was obtained by performing the same operation as in Example 1 except that the purification catalyst component was replaced with Ce _0.5 Bi _0.1 Pr _0.4 O _{2 + δ} from CeO ₂ .

[Synthesis of coexisting substances]
The same operation as in Example 1 was performed to produce SrZrO ₃ , and a coexisting substance according to Example 9 was obtained.

[Exhaust gas purification material synthesis]
The purification catalyst component and the coexisting substance were weighed so that the mass ratio of the purification catalyst component and the coexistence substance was 80:20, and mixed in a mortar for 15 minutes to obtain an exhaust gas purification material according to Example 9.

(Example 10)
[Purification catalyst component synthesis]
A purification catalyst component according to Example 10 was obtained by performing the same operation as in Example 1 except that the purification catalyst component was replaced with Ce _0.5 Bi _0.1 Pr _0.4 O _{2 + δ} from CeO ₂ .

[Synthesis of coexisting substances]
The same operation as in Example 1 was performed to produce Sr ₃ Al ₂ O ₆ , and a coexisting material according to Example 10 was obtained.

[Exhaust gas purification material synthesis]
The purification catalyst component and the coexisting substance were weighed so that the mass ratio of the purification catalyst component and the coexistence substance was 77:23, and mixed in a mortar for 15 minutes to obtain an exhaust gas purification material according to Example 10.

(Example 11)
[Purification catalyst component synthesis]
A purification catalyst component according to Example 11 was obtained by performing the same operation as in Example 1 except that the purification catalyst component was replaced with Ce _0.5 Bi _0.1 Pr _0.4 O _{2 + δ} from CeO ₂ .

[Synthesis of coexisting substances]
BaAl ₂ O ₄ was produced in the same manner as in Example 1 to obtain a coexisting substance according to Example 11.

[Exhaust gas purification material synthesis]
The purification catalyst component and the coexisting substance were weighed so that the mass ratio of the purification catalyst component and the coexistence substance was 78:22, and mixed in a mortar for 15 minutes to obtain an exhaust gas purification material according to Example 11.

(Comparative Example 3)
[Purification catalyst component synthesis]
The same operation as in Example 1 was performed to obtain a purification catalyst component containing Ce _0.5 Bi _0.1 Pr _0.4 O _{2 + δ according} to Comparative Example 3.

[Synthesis of coexisting substances]
Coexisting materials were not synthesized.

[Exhaust gas purification material synthesis]
Only the purification catalyst component was mixed in a mortar for 15 minutes to obtain an exhaust gas purification material according to Comparative Example 3.

(Comparative evaluation between Examples 5-11 and Comparative Example 3)
The relationship between Examples 5-11 and Comparative Example 3 will be described. In contrast to Comparative Example 1 consisting only of the purification catalyst component, Example 5 is a case where 30% by mass of a coexisting substance (BaBiO ₃ ) coexists with the purification catalyst component according to Comparative Example 3. In Example 6, 50% by mass of a coexisting substance (SrBi ₄ O ₇ ) coexists with the purification catalyst component according to Comparative Example 3. In Example 7, 40% by mass of a coexisting substance (Sr _0.3 Bi _0.7 O _δ ) coexists with the purification catalyst component according to Comparative Example 3.

In Example 8, 24% by mass of a coexisting substance (BaZrO ₃ ) coexists with the purification catalyst component according to Comparative Example 3. In Example 9, 20% by mass of a coexisting substance (SrZrO ₃ ) coexists with the purification catalyst component according to Comparative Example 3. In Example 10, 23% by mass of a coexisting substance (Sr ₃ Al ₂ O ₆ ) coexists with the purification catalyst component according to Comparative Example 3. In Example 11, 22% by mass of a coexisting substance (BaAl ₂ O ₄ ) coexists with the purification catalyst component according to Comparative Example 3.

  Here, from the evaluation results according to Examples 5 to 11 and Comparative Example 3, the purification catalyst components and the coexisting substances constituting the obtained exhaust gas purification materials according to Examples 5 to 11 were evaluated. The said evaluation was performed by the affinity combustion to acid gas and PM combustion temperature evaluation of the sample obtained by the sulfur poisoning process.

[Affinity Evaluation for Acid Gas]
<Evaluation of Example 5>
The affinity evaluation of the obtained exhaust gas purifying material according to Example 5 to acid gas was performed in the same manner as in Example 1.

  From the results of the affinity evaluation to the acid gas, the affinity of the purification catalyst component according to Comparative Example 3 to the acid gas and the affinity of the coexisting substance according to Example 5 to the acid gas are the ratio of the desorption area. When expressed in terms of purification catalyst component: coexisting substance = 1.0: 5.6. That is, it was found that the coexisting substance according to Example 5 can adsorb a larger amount of NOx than the purification catalyst component.

Moreover, the maximum point temperature in the desorption curve of the coexisting substance according to Example 5 was 88 ° C. higher than that of the purification catalyst component.
From the above results, it was found that the coexisting substance according to Example 5 has higher affinity for acidic gas than the purification catalyst component.

<Evaluation of Example 6>
The affinity evaluation of the obtained exhaust gas purifying material according to Example 6 to the acid gas was performed in the same manner as in Example 1.

  From the results of the affinity evaluation to the acid gas, the affinity of the purification catalyst component according to Comparative Example 3 to the acid gas and the affinity of the coexisting substance according to Example 6 to the acid gas are the ratio of the desorption area. When expressed using, purification catalyst component: coexisting substance = 1.0: 3.7. That is, it was found that the coexisting substance according to Example 6 can adsorb a larger amount of NOx than the purification catalyst component.

Further, the maximum point temperature in the desorption curve of the coexisting substance according to Example 6 was 58 ° C. higher than that of the purification catalyst component.
From the above results, it was found that the coexisting substance according to Example 6 has higher affinity for the acidic gas than the purification catalyst component.

[PM combustion temperature evaluation of samples obtained by sulfur poisoning]
<Evaluation of Example 5>
The PM combustion temperature evaluation of the sample obtained by the above-described sulfur poisoning treatment was performed on the exhaust gas purifying materials according to Example 5 and Comparative Example 3. The evaluation results are shown in Table 1 and FIG. From the evaluation results, the following became clear. That is, in the exhaust gas purifying material according to Example 5, the increase in the combustion temperature of carbon black after the sulfur poisoning treatment is significantly suppressed from the increase in the combustion temperature in Comparative Example 3 due to the presence of the coexisting substances. .

  Compared with the purification catalyst component according to Example 5 and Comparative Example 3, the combustion temperature of the coexisting substance carbon black according to Example 5 is higher by 50 ° C. or more than the purification catalyst component. Furthermore, the purification catalyst component in the exhaust gas purification material according to Example 5 is 70% by mass, and the purification catalyst component in the exhaust gas purification material according to Comparative Example 3 is 100% by mass. That is, although the purification catalyst component in the exhaust gas purification material according to Example 5 is less than the purification catalyst component in the exhaust gas purification material according to Comparative Example 3, the carbon black after sulfur treatment by mixing of coexisting substances The increase in the combustion temperature was 34 ° C., which was significantly suppressed from the increase in the combustion temperature of Comparative Example 3 at 127 ° C. In the exhaust gas purifying material according to Example 5, it is considered that sulfur is selectively adsorbed by the coexisting substance due to the coexistence of the coexisting substance, and the sulfur adsorption to the purification catalyst component is suppressed.

Further, in the exhaust gas purifying material according to Example 5, the combustion temperature of the carbon black after regeneration is only increased by 10 ° C. compared with that before the treatment, and regeneration is promoted by the presence of coexisting substances. I understand. On the other hand, since the exhaust gas purifying material according to Comparative Example 3 is composed only of the purifying catalyst component, the combustion temperature of the carbon black after regeneration is 48 ° C. higher than that before the treatment and is sufficiently regenerated. I understand that there is not.
That is, it was found that the coexisting substance according to Example 5 has a great effect on both “suppressing deterioration after sulfur treatment” and “promotion of regeneration”.

<Evaluation of Example 6>
The PM combustion temperature evaluation of the sample obtained by the sulfur poisoning process described above was performed on the exhaust gas purifying materials according to Example 6 and Comparative Example 3. The evaluation results are shown in Table 1 and FIG. From the evaluation results, the following became clear. That is, in the exhaust gas purifying material according to Example 6, the increase in the combustion temperature of carbon black after sulfur poisoning treatment is 29 ° C. due to the presence of coexisting substances, which is significantly higher than the increase in the combustion temperature in Comparative Example 3. It is suppressed.

  The purification catalyst component in the exhaust gas purification material according to Example 6 is 50% by mass, and the purification catalyst component in the exhaust gas purification material according to Comparative Example 3 is 100% by mass. That is, although the purification catalyst component in the exhaust gas purification material according to Example 6 is less than the purification catalyst component in the exhaust gas purification material according to Comparative Example 3, the carbon black after sulfur treatment by mixing of coexisting substances The increase in the combustion temperature is greatly suppressed. In the exhaust gas purifying material according to Example 6, it is considered that sulfur is selectively adsorbed by the coexisting substance due to the coexistence of the coexisting substance, and the sulfur adsorption to the purification catalyst component is suppressed.

Further, in the exhaust gas purifying material according to Example 6, the combustion temperature of the carbon black after regeneration remains at an increase of 9 ° C., and it can be seen that regeneration is promoted by the presence of coexisting substances.
That is, it was found that the coexisting substance according to Example 6 has a great effect on both “suppressing deterioration after sulfur treatment” and “promotion of regeneration”.

<Evaluation of Example 7>
The PM combustion temperature evaluation of the sample obtained by the sulfur poisoning process described above was performed on the exhaust gas purifying materials according to Example 7 and Comparative Example 3. The evaluation results are shown in Table 1 and FIG. From the evaluation results, the following became clear. That is, in the exhaust gas purifying material according to Example 7, the increase in the combustion temperature of carbon black after sulfur poisoning treatment is 33 ° C. due to the presence of coexisting substances, which is significantly higher than the increase in the combustion temperature in Comparative Example 3. It is suppressed.

  The purification catalyst component in the exhaust gas purification material according to Example 7 is 60% by mass, and the purification catalyst component in the exhaust gas purification material according to Comparative Example 3 is 100% by mass. That is, although the purification catalyst component in the exhaust gas purification material according to Example 7 is less than the purification catalyst component in the exhaust gas purification material according to Comparative Example 3, the carbon black after sulfur treatment by mixing of coexisting substances The increase in the combustion temperature is greatly suppressed. This is considered to be due to the effect that in the exhaust gas purifying material according to Example 7, sulfur was selectively adsorbed by the coexisting substances due to the coexistence of the coexisting substances, and the adsorption of sulfur to the purification catalyst component was suppressed.

Further, in the exhaust gas purifying material according to Example 7, it can be seen that the combustion temperature of the carbon black after regeneration remains only 11 ° C. higher than that before treatment, and regeneration is promoted by the presence of coexisting substances. .
That is, it was found that the coexisting substance according to Example 7 has a great effect on both “suppressing deterioration after sulfur treatment” and “promotion of regeneration”.

<Evaluation of Example 8>
The PM combustion temperature evaluation of the sample obtained by the above-described sulfur poisoning treatment was performed on the exhaust gas purifying materials according to Example 8 and Comparative Example 3. The evaluation results are shown in Table 1 and FIG. From the evaluation results, the following became clear. That is, in the exhaust gas purifying material according to Example 8, the increase in the combustion temperature of carbon black after sulfur poisoning treatment is 75 ° C. due to the presence of coexisting substances, which is significantly higher than the increase in the combustion temperature in Comparative Example 3. It is suppressed.

  Compared to the purification catalyst component according to Example 8 and Comparative Example 3, the combustion temperature of the coexisting material carbon black according to Example 8 is 100 ° C. or more higher than that of the purification catalyst component. Furthermore, the purification catalyst component in the exhaust gas purification material according to Example 8 is 76% by mass, and the purification catalyst component in the exhaust gas purification material according to Comparative Example 3 is 100% by mass. That is, although the purification catalyst component in the exhaust gas purification material according to Example 8 is less than the purification catalyst component in the exhaust gas purification material according to Comparative Example 3, the carbon black after sulfur treatment by mixing of coexisting substances The increase in the combustion temperature is greatly suppressed. This is considered to be due to the effect that in the exhaust gas purifying material according to Example 8, sulfur is selectively adsorbed by the coexisting substance due to the coexistence of the coexisting substance, and the adsorption of sulfur to the purification catalyst component is suppressed.

Further, in the exhaust gas purifying material according to Example 8, the combustion temperature of the carbon black after the regeneration remains only 23 ° C. higher than that before the treatment, and it can be seen that the regeneration is promoted by the presence of the coexisting substances. .
That is, it was found that the coexisting substance according to Example 8 has a great effect on both “suppressing deterioration after sulfur treatment” and “promotion of regeneration”.

<Evaluation of Example 9>
The PM combustion temperature evaluation of the sample obtained by the above-described sulfur poisoning treatment was performed on the exhaust gas purifying materials according to Example 9 and Comparative Example 3. The evaluation results are shown in Table 1 and FIG. From the evaluation results, the following became clear. That is, in the exhaust gas purifying material according to Example 9, the increase in the combustion temperature of carbon black after sulfur poisoning treatment due to the presence of coexisting substances is 47 ° C., which is significantly higher than the increase in the combustion temperature in Comparative Example 3. It is suppressed.

  Compared with the purification catalyst component according to Example 9 and Comparative Example 3, the combustion temperature of the coexisting substance carbon black according to Example 9 is 100 ° C. or more higher than that of the purification catalyst component. Furthermore, the purification catalyst component in the exhaust gas purification material according to Example 9 is 80% by mass, and the purification catalyst component in the exhaust gas purification material according to Comparative Example 3 is 100% by mass. That is, although the purification catalyst component in the exhaust gas purification material according to Example 9 is less than the purification catalyst component in the exhaust gas purification material according to Comparative Example 3, the carbon black after sulfur treatment by mixing of coexisting substances The increase in the combustion temperature is greatly suppressed. This is considered to be due to the effect that in the exhaust gas purifying material according to Example 9, sulfur is selectively adsorbed by the coexisting substance due to the coexistence of the coexisting substance, and the adsorption of sulfur to the purification catalyst component is suppressed.

Further, in the exhaust gas purifying material according to Example 9, it can be seen that the combustion temperature of the carbon black after regeneration remains only 9 ° C. higher than that before treatment, and regeneration is promoted by the presence of coexisting substances. .
That is, it was found that the coexisting substance according to Example 9 has a great effect on both “suppressing deterioration after sulfur treatment” and “promotion of regeneration”.

<Evaluation of Example 10>
The PM combustion temperature evaluation of the sample obtained by the above-described sulfur poisoning treatment was performed on the exhaust gas purifying materials according to Example 10 and Comparative Example 3. The evaluation results are shown in Table 1 and FIG. From the evaluation results, the following became clear. That is, in the exhaust gas purifying material according to Example 10, the increase in the combustion temperature of carbon black after the sulfur poisoning treatment is 64 ° C. due to the presence of the coexisting substances, which is significantly higher than the increase in the combustion temperature in Comparative Example 3. It is suppressed.

  Compared with the purification catalyst component according to Example 10 and Comparative Example 3, the combustion temperature of the coexisting material carbon black according to Example 10 is higher by 150 ° C. or more than the purification catalyst component. Furthermore, the purification catalyst component in the exhaust gas purification material according to Example 7 is 80% by mass, and the purification catalyst component in the exhaust gas purification material according to Comparative Example 3 is 100% by mass. That is, although the purification catalyst component in the exhaust gas purification material according to Example 10 is less than the purification catalyst component in the exhaust gas purification material according to Comparative Example 3, the carbon black after sulfur treatment by mixing coexisting substances The increase in the combustion temperature is greatly suppressed. This is considered to be due to the effect that in the exhaust gas purifying material according to Example 10, sulfur is selectively adsorbed by the coexisting substances due to the coexistence of the coexisting substances, and the adsorption of sulfur to the purification catalyst component is suppressed.

Further, in the exhaust gas purifying material according to Example 10, the combustion temperature of the carbon black after regeneration remains at 12 ° C. higher than that before the treatment, and it can be seen that regeneration is promoted by the presence of coexisting substances. .
That is, it was found that the coexisting substance according to Example 10 has a great effect on both “suppression of deterioration after sulfur treatment” and “promotion of regeneration”.

<Evaluation of Example 11>
The PM combustion temperature evaluation of the sample obtained by the above-described sulfur poisoning treatment was performed on the exhaust gas purifying materials according to Example 11 and Comparative Example 3. The evaluation results are shown in Table 1 and FIG. From the evaluation results, the following became clear. That is, in the exhaust gas purifying material according to Example 11, the increase in the combustion temperature of carbon black after the sulfur poisoning treatment is 84 ° C. due to the presence of the coexisting substances, which is significantly higher than the increase in the combustion temperature in Comparative Example 3. It is suppressed.

  Compared with the purification catalyst component according to Example 11 and Comparative Example 3, the combustion temperature of the coexisting material carbon black according to Example 11 is higher by 150 ° C. or more than the purification catalyst component. Furthermore, the purification catalyst component in the exhaust gas purification material according to Example 7 is 78% by mass, and the purification catalyst component in the exhaust gas purification material according to Comparative Example 3 is 100% by mass. That is, although the purification catalyst component in the exhaust gas purification material according to Example 11 is less than the purification catalyst component in the exhaust gas purification material according to Comparative Example 3, the carbon black after sulfur treatment by mixing of coexisting substances The increase in the combustion temperature is greatly suppressed. In the exhaust gas purifying material according to Example 11, it is considered that sulfur is selectively adsorbed by the coexisting substance due to the coexistence of the coexisting substance, and the sulfur adsorption to the purification catalyst component is suppressed.

Further, in the exhaust gas purifying material according to Example 11, the combustion temperature of the carbon black after regeneration remains at a rise of 23 ° C. compared to that before the treatment, and it can be seen that regeneration is promoted by the presence of coexisting substances. .
That is, it was found that the coexisting substance according to Example 11 has a great effect on both “suppressing deterioration after sulfur treatment” and “promotion of regeneration”.

(Example 12)
[Purification catalyst component synthesis]
A purified catalyst component according to Example 12 was obtained by performing the same operation as in Example 1 except that the purified catalyst component was replaced by Ce _{0.8 2} to La _0.8 Ba _0.2 FeO ₃ .

[Synthesis of coexisting substances]
The same operation as in Example 1 was performed to produce BaBiO ₃ to obtain a coexisting substance according to Example 12.

[Exhaust gas purification material synthesis]
The purification catalyst component and the coexisting substance were weighed so that the mass ratio of the purification catalyst component and the coexistence substance was 67:33, and mixed in a mortar for 15 minutes to obtain an exhaust gas purification material according to Example 12.

(Comparative Example 4)
[Purification catalyst component synthesis]
The same operation as in Example 1 was performed to obtain a purification catalyst component containing La _0.8 Ba _0.2 FeO _{3 according} to Comparative Example 4.

[Synthesis of coexisting substances]
Coexisting materials were not synthesized.

[Exhaust gas purification material synthesis]
Only the purification catalyst component was mixed in a mortar for 15 minutes to obtain an exhaust gas purification material according to Comparative Example 4.

(Evaluation of Example 12 and Comparative Example 4)
The relationship between Example 12 and Comparative Example 4 will be described. In contrast to Comparative Example 4 consisting only of the purification catalyst component, Example 12 is one in which 33% by mass of a coexisting substance (BaBiO ₃ ) coexists with the purification catalyst component according to Comparative Example 4.

  Here, from the evaluation results according to Example 12 and Comparative Example 4, the purification catalyst component and the coexisting substances constituting the obtained exhaust gas purification material according to Example 12 were evaluated. The evaluation was performed by PM combustion temperature evaluation of a sample obtained by sulfur poisoning treatment.

[PM combustion temperature evaluation of samples obtained by sulfur poisoning]
<Evaluation of Example 12>
The exhaust gas purifying material according to Example 12 and Comparative Example 4 was evaluated for affinity to the above-described sulfur-containing acidic gas. The evaluation results are shown in Table 1 and FIG. From the evaluation results, the following became clear. That is, in the exhaust gas purifying material according to Example 12, the increase in the combustion temperature of carbon black after the sulfur poisoning treatment is 32 ° C. due to the presence of the coexisting substances, which is almost the same as the increase in the combustion temperature of 31 ° C. in Comparative Example 4. It was equivalent.

  Compared to the purification catalyst component according to Example 12 and Comparative Example 4, the combustion temperature of the coexisting substance carbon black according to Example 12 is 20 ° C. or more higher than that of the purification catalyst component. Furthermore, the purification catalyst component in the exhaust gas purification material according to Example 12 is 67% by mass, and the purification catalyst component in the exhaust gas purification material according to Comparative Example 4 is 100% by mass. That is, although the purification catalyst component in the exhaust gas purification material according to Example 12 is less than the purification catalyst component in the exhaust gas purification material according to Comparative Example 4, carbon black after sulfur treatment by mixing of coexisting substances The increase in the combustion temperature is greatly suppressed. This is considered to be due to the effect that in the exhaust gas purifying material according to Example 12, sulfur is selectively adsorbed by the coexisting substance due to the coexistence of the coexisting substance, and the adsorption of sulfur to the purification catalyst component is suppressed.

  Further, in the exhaust gas purifying material according to Example 12, the combustion temperature of carbon black after regeneration remains at an increase of 18 ° C. compared with that before treatment, and regeneration is promoted by the presence of coexisting substances. I understand. On the other hand, since the exhaust gas purifying material according to Comparative Example 4 is composed only of the purifying catalyst component, the combustion temperature of the carbon black after regeneration is 22 ° C. higher than that before the treatment and is sufficiently regenerated. I understand that there is not. That is, it was found that the coexisting substance according to Example 12 has a great effect on “promotion of regeneration”.

(Example 13)
[Purification catalyst component synthesis]
A purification catalyst component according to Example 13 was obtained by performing the same operation as in Example 1 except that the purification catalyst component was replaced with CeO ₂ of BET100.

[Synthesis of coexisting substances]
The same operation as in Example 1 was performed to produce BaBiO ₃ , and a coexisting substance according to Example 13 was obtained.

[Exhaust gas purification material synthesis]
The purification catalyst component and the coexisting substance were weighed so that the mass ratio of the purification catalyst component and the coexistence substance was 6: 4, and mixed in a mortar for 15 minutes to obtain an exhaust gas purification material according to Example 13.

(Example 14)
[Purification catalyst component synthesis]
A purification catalyst component according to Example 14 was obtained by performing the same operation as in Example 1 except that the purification catalyst component was replaced with CeO ₂ of BET160.

[Synthesis of coexisting substances]
BaBiO ₃ was produced in the same manner as in Example 1 to obtain a coexisting substance according to Example 14.

[Exhaust gas purification material synthesis]
The purification catalyst component and the coexisting substance were weighed so that the mass ratio of the purification catalyst component and the coexistence substance was 6: 4, and mixed in a mortar for 15 minutes to obtain an exhaust gas purification material according to Example 14.
(Comparative Example 5)
[Purification catalyst component synthesis]
Except for replacing purification catalyst component in the reagent CeO ₂ was obtained purifying catalyst component according to Comparative Example 5 The same operation as in Example 1.

[Synthesis of coexisting substances]
The same operation as in Example 1 was performed to produce BaBiO ₃ to obtain a coexisting substance according to Comparative Example 5.

[Exhaust gas purification material synthesis]
The purification catalyst component and the coexisting substance were weighed so that the mass ratio of the purification catalyst component and the coexistence substance was 6: 4, and mixed in a mortar for 15 minutes to obtain an exhaust gas purification material according to Comparative Example 5.

(Comparative evaluation of Examples 1, 13, 14 and Comparative Example 5)
The relationship between Examples 1, 13, and 14 and Comparative Example 5 will be described with reference to FIG. In the exhaust gas purifying materials according to Examples 1, 13, and 14 in which the specific surface area according to the BET method of the mixed powder characteristics of the purification catalyst component and the coexisting substance is within the range of 10 to 100 m ² / g, the specific surface area is large. The adsorption area of sulfur is also large, and it is considered that sulfur is selectively adsorbed by the coexisting substance due to the presence of the coexisting substance, and the adsorption of sulfur to the purification catalyst component is suppressed. On the other hand, since the exhaust gas purifying material according to Comparative Example 1 has a small specific surface area, the combustion temperature of carbon black before sulfur poisoning is high. From this, the specific surface area by the BET method of the characteristics of the mixed powder is preferably 10 to 100 m ² / g.

2 is an X-ray diffraction pattern of cerium oxide according to Example 1. FIG. _{2 is} an X-ray diffraction pattern of BaBiO _{3 according} to Example 1. FIG. It is a graph which shows the combustion temperature of the carbon black of the exhaust gas purification material before and after sulfur poisoning treatment and after regeneration treatment. It is a graph which shows the combustion temperature of the carbon black of the exhaust gas purification material before and after sulfur poisoning treatment and after regeneration treatment. It is a graph which shows the combustion temperature of the carbon black of the exhaust gas purification material before and after sulfur poisoning treatment and after regeneration treatment. It is a graph which shows the combustion temperature of the carbon black of the exhaust gas purification material before and after sulfur poisoning treatment and after regeneration treatment. It is a graph which shows the combustion temperature of the carbon black of the exhaust gas purification material before and after sulfur poisoning treatment and after regeneration treatment.

Claims (10)

An exhaust gas purifying material for lowering the combustion temperature of particulate matter mainly composed of carbon contained in exhaust gas of a diesel engine,
A purification catalyst component having a catalytic action to lower the combustion temperature of the particulate matter;
A coexisting substance which is a composite oxide containing at least one of an alkali metal and an alkaline earth metal that recovers the catalytic action reduced by poisoning of the sulfur-containing acidic gas, and at least one of an acidic element and an amphoteric element ;
See containing at least one kind of an element <br/> selected from platinum group elements,
The coexisting substance is
If the temperature rises above 500 ° C,
Restoring the catalytic action under one or both of the conditions where the concentration of the carbon monoxide component is 100 ppm or more or the concentration of the hydrocarbon component is 200 ppm or more;
The coexisting substance is contained in an amount of 5 to 50% by mass of the entire exhaust gas purification material,
An exhaust gas purification material having a specific surface area of 10 m ² / g or more and 100 m ² / g or less by the BET method of the exhaust gas purification material. The exhaust gas purification material according to claim 1, wherein the purification catalyst component has a crystal structure of perovskite, spinel, corundum, or fluorite. The purification catalyst component exhaust gas purification material that is either crab of claims 1-2 containing cerium. The exhaust gas purification material according to claim 3 , wherein the purification catalyst component is a complex oxide having a fluorite structure containing cerium. The coexisting material is a composite oxide containing at least one element selected from the group consisting of alkali metals and alkaline earth metals and at least one element selected from the group consisting of acidic elements and amphoteric elements The exhaust gas purifying material according to any one of claims 1 to 4 , wherein When the coexisting material is expressed as A, at least one element selected from the alkali metals and alkaline earth metals, and B as at least one element selected from the acidic elements and amphoteric elements, General formula A _(1-x) B _x O _δ (where 0 <x ≦ 0.9, 0 <δ <10)
The exhaust gas purifying material according to claim 5 , wherein the exhaust gas purifying material is a composite oxide satisfying the above. The alkali metal is potassium and / or cesium, the alkaline earth metal is at least one element selected from the group consisting of barium, strontium, calcium and magnesium, and the acidic element is bismuth. The exhaust gas purification material according to claim 5 or 6 , wherein the amphoteric element is at least one element selected from the group consisting of titanium, zirconium, aluminum, gallium, indium and tin. The exhaust gas purifying material according to claim 7 , wherein the alkaline earth metal is barium and / or strontium, the acidic element is bismuth, and the amphoteric element is zirconium and / or aluminum. An exhaust gas purification filter using the exhaust gas purification material according to any one of claims 1 to 8 . The exhaust gas purification filter according to claim 9 , further comprising an exhaust gas purification material comprising at least one element selected from platinum group elements in addition to the exhaust gas purification material.

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