Selective catalytic reduction catalyst material, selective catalytic reduction catalyst using the same, and method for producing selective catalytic reduction catalyst material

Abstract

To provide means that enables enhancement of NOx purification performance in a selective catalytic reduction catalyst.SOLUTION: A selective catalytic reduction catalyst material comprises a Cu-supported CHA-type zeolite and a metal oxide, in which a parameter relating to the electronegativity of a metal contained in the metal oxide is controlled to be within a predetermined range.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a material for a selective catalytic reduction catalyst, a selective catalytic reduction catalyst using the same, and a method for producing the material for a selective catalytic reduction catalyst. [Background technology]

[0002] Nitrogen oxides (NO) contained in exhaust gases emitted from internal combustion engines such as automobile engines x To reduce emissions of NOx (a general term for NO, NO2, etc.), selective catalytic reduction (SCR) has been put into practical use. SCR converts NOx into N2 and HO by catalytic reduction with ammonia, a reducing agent, in the presence of a metal ion-exchanged zeolite catalyst.

[0003] For example, Patent Document 1 discloses a catalyst composition suitable for use as a selective catalytic reduction catalyst, which comprises small pore molecular sieve particles impregnated with a promoter metal, having a pore structure and a maximum ring size of eight tetrahedral atoms, and metal oxide particles containing one or more oxides of transition metals or lanthanides of Group 3 or 4 of the periodic table, dispersed within the small pore molecular sieve particles and outside the pore structure of the small pore molecular sieve particles. According to Patent Document 1, the above-mentioned configuration allows for enhanced NO production at low and / or high temperatures. x It is said that this can result in reduction and reduced N2O production at low and / or high temperatures. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 2019-502550 Summary of the Invention [Problem to be solved by the invention]

[0005] However, in recent years, regulations on automobile exhaust gas have become stricter, and further reductions in NOx emissions are required.

[0006] Therefore, an object of the present invention is to provide a means for improving the NOx purification performance of a selective catalytic reduction catalyst. [Means for solving the problem]

[0007] The present inventors have conducted extensive research to solve the above-mentioned problems, and as a result, have found that in a selective catalytic reduction catalyst material containing Cu-supported CHA-type zeolite and an inorganic oxide, the above-mentioned problems can be solved by controlling a parameter related to the electronegativity of the metal contained in the inorganic oxide within a predetermined range, thereby completing the present invention.

[0008] That is, one embodiment of the present invention is a selective catalytic reduction catalyst material comprising a Cu-supported CHA-type zeolite and an inorganic oxide, wherein the inorganic oxide is a single metal oxide or a metal oxide mixture containing at least two single metal oxides, and the parameter E of the inorganic oxide calculated by the following formula 1 is greater than 1.22 and less than 1.35.

[0009]

number

[0010] In the above formula 1, E k is the electronegativity of the metal of the single metal oxide k in the inorganic oxide, and x k is the ratio of the mass of the single metal oxide k to the total mass of the inorganic oxide, and n is the number of types of single metal oxides constituting the inorganic oxide, and is an integer of 1 or more. [Effects of the Invention]

[0011] According to the present invention, the NOx purification performance of a selective catalytic reduction catalyst can be improved. DETAILED DESCRIPTION OF THE INVENTION

[0012] Hereinafter, embodiments of the present invention will be described, but the technical scope of the present invention should be defined based on the claims and is not limited to the following embodiments. In this specification, the numerical range "A to B" means "greater than or equal to A and less than or equal to B." Furthermore, "A and / or B" means "either A or B" or "both A and B."

[0013] <Selective catalytic reduction catalyst materials> One embodiment of the present invention is a selective catalytic reduction catalyst material comprising a Cu-supported CHA-type zeolite and an inorganic oxide, wherein the inorganic oxide is a single metal oxide or a metal oxide mixture containing at least two single metal oxides, and the parameter E of the inorganic oxide calculated by the following formula 1 is greater than 1.22 and less than 1.35:

[0014]

number

[0015] In the above formula 1, E k is the electronegativity of the metal of the single metal oxide k in the inorganic oxide, and x k is the ratio of the mass of the single metal oxide k to the total mass of the inorganic oxide, and n is the number of types of single metal oxides constituting the inorganic oxide, and is an integer of 1 or more.

[0016] According to the studies of the present inventors, it has been found that a selective catalytic reduction catalyst containing a selective catalytic reduction catalyst material having the above-described configuration exhibits improved NOx purification performance. Although the mechanism by which this effect is achieved is not completely clear, the following mechanism is presumed. That is, the inorganic oxide, which has appropriate acid-base properties, (1) suppresses Cu elution due to low interaction with Cu in the zeolite cages that serve as active sites, and (2) improves performance by realizing appropriate adsorption of NH3, a basic reducing agent. Note that the above mechanism is merely based on speculation, and whether it is correct or incorrect does not affect the technical scope of the present invention.

[0017] [Cu-loaded CHA-type zeolite] The selective catalytic reduction catalyst material according to this embodiment essentially contains Cu-supported CHA-type zeolite. It is believed that Cu ions in the Cu-supported CHA-type zeolite function as a catalyst for the reaction of NOx and NH3 to N2 and HO.

[0018] As used herein, "CHA-type zeolite" refers to a zeolite having a skeletal structure defined by the International Zeolite Association (IZA) as the skeletal code "CHA." Note that the skeletal code defines only the geometric structure of the skeleton, and may include zeolites with different compositions and lattice constants. Furthermore, as used herein, "Cu-supported CHA-type zeolite" refers to a CHA-type zeolite that has been ion-exchanged with Cu.

[0019] The silica / alumina ratio (SiO2 / Al2O3 (molar ratio); SAR) in Cu-supported CHA-type zeolite is not particularly limited, but is preferably 10 to 50, more preferably 10 to 30, and even more preferably 20 to 25. A silica / alumina ratio of 10 or more is preferred because the proportion of more highly active Cu sites (ZCuOH) increases relative to the slightly less active Cu sites (Z2Cu) (Z: Al sites of the zeolite). A silica / alumina ratio of 50 or less is preferred because it allows a large amount of Cu, which serves as an active site, to be introduced into the zeolite.

[0020] In Cu-loaded CHA-type zeolite, the Cu loading amount (the amount of Cu loaded by ion exchange) depends on the silica / alumina ratio of the Cu-loaded CHA-type zeolite. This is because the smaller the silica / alumina ratio (the higher the alumina ratio), the greater the number of negative charges and the greater the number of cations that can be loaded. The Cu / Al (molar ratio) in Cu-loaded CHA-type zeolite is preferably 0.2 to 0.5, more preferably 0.3 to 0.45, and even more preferably 0.35 to 0.4. A Cu / Al (molar ratio) of 0.2 or more is preferred because it increases the amount of Cu that serves as active sites. A Cu / Al (molar ratio) of 0.5 or less is preferred because it suppresses NH3 oxidation performance and improves N2 selectivity at high temperatures of 500°C or higher.

[0021] The content of Cu-supported CHA-type zeolite in the selective catalytic reduction catalyst material according to this embodiment is not particularly limited, but from the viewpoint of further improving the reaction efficiency of the selective catalytic reduction reaction, it is preferably 80 to 97 mass%, more preferably 82 to 95 mass%, even more preferably 85 to 93 mass%, and particularly preferably 87 to 90 mass%, relative to 100 mass% of the total mass of the inorganic oxide and the Cu-supported CHA-type zeolite.

[0022] [Inorganic oxides] The selective catalytic reduction catalyst material according to this embodiment essentially contains an inorganic oxide. The inorganic oxide functions as a binder before calcination and can contribute to improving the reaction efficiency of the selective catalytic reduction reaction after calcination.

[0023] In this embodiment, the inorganic oxide is a single metal oxide or a metal oxide mixture containing at least two single metal oxides. As used herein, the term "single metal oxide" refers to a metal oxide containing only one metal element. Examples of single metal oxides (including single metal oxides constituting a metal oxide mixture) include, but are not limited to, zirconia (ZrO), alumina (AlO), ceria (CeO), yttria (YO), lanthana (LaO), titania (TiO), niobia (NbO), tantalum oxide (TaO), and strontium oxide (SrO).

[0024] This embodiment is characterized in that the inorganic oxide has a parameter E calculated by the following formula 1 that is greater than 1.22 and less than 1.35.

[0025]

number

[0026] In the above formula 1, E k is the electronegativity of the metal in the single metal oxide k in the inorganic oxide. In this specification, "electronegativity" refers to Pauling's electronegativity. Below, we will list the main metals and their electronegativity.

[0027] [Table 1]

[0028] In the above formula 1, x k is the ratio of the mass of the single metal oxide k to the total mass of the inorganic oxides. k The sum is 1.

[0029] In the above formula 1, n is the number of types of single metal oxides constituting the inorganic oxide, and is an integer of 1 or more. n is preferably an integer of 1 to 5, more preferably an integer of 1 to 3, and even more preferably 1 or 2.

[0030] The parameter E is greater than 1.22 and less than 1.35. A parameter E of 1.22 or less is undesirable because the basicity of the catalyst surface increases, inhibiting NH3 adsorption. A parameter E of 1.35 or more is undesirable because the affinity between Cu and the metal oxide increases, promoting Cu elution. From the viewpoint of further improving NOx purification performance, the parameter E is preferably greater than 1.22 and less than 1.33, more preferably 1.23 to 1.31, even more preferably 1.24 to 1.30, particularly preferably 1.25 to 1.29, and most preferably 1.27 to 1.28. The parameter E can be controlled by adjusting the type and amount of the single metal oxide constituting the inorganic oxide.

[0031] According to one embodiment of the present invention, the inorganic oxide preferably contains zirconia, and more preferably is zirconia. In these cases, as will be described in detail in the <Production method of selective catalytic reduction catalyst> below, by controlling the average particle size of the zirconia precursor in the slurry, the NOx purification performance of the selective catalytic reduction catalyst can be further improved.

[0032] According to another embodiment of the present invention, the inorganic oxide is preferably a metal oxide mixture containing at least two single metal oxides. In this case, the metal oxide mixture preferably contains at least two selected from the group consisting of zirconia, alumina, ceria, yttria, and lanthana, and more preferably is composed of zirconia and yttria, zirconia and lanthana, ceria and alumina, ceria and zirconia, or alumina and lanthana. This configuration facilitates control of parameter E, thereby further improving the NOx purification performance of the selective catalytic reduction catalyst.

[0033] The content of the inorganic oxide in the selective catalytic reduction catalyst material according to this embodiment is not particularly limited, but from the viewpoint of further improving the reaction efficiency of the selective catalytic reduction reaction after calcination, it is preferably 3 to 20 mass%, more preferably 5 to 18 mass%, even more preferably 7 to 15 mass%, and particularly preferably 10 to 13 mass%, relative to 100 mass% of the total mass of the inorganic oxide and the Cu-supported CHA-type zeolite.

[0034] [Other ingredients] The selective catalytic reduction catalyst material according to this embodiment may further contain components other than the Cu-supported CHA-type zeolite and inorganic oxide, as long as the effects of the present invention are not significantly impaired. Examples of the other components include Cu and Fe-supported FAU-type zeolite and MFI-type zeolite.

[0035] The content of other components in the selective catalytic reduction catalyst material according to this embodiment is not particularly limited, but is preferably 0 to 5 mass%, more preferably 0 to 3 mass%, even more preferably 0 to 1 mass%, and particularly preferably 0 mass%, relative to 100 mass% of the total mass of the selective catalytic reduction catalyst material (i.e., the selective catalytic reduction catalyst material consists only of Cu-supported CHA-type zeolite and inorganic oxide).

[0036] <Selective catalytic reduction catalyst> According to one aspect of the present invention, there is provided a catalyst having a catalyst layer containing the selective catalytic reduction catalyst material on a refractory three-dimensional structure.

[0037] [Fireproof three-dimensional structure] The refractory three-dimensional structure serves as a support for the catalyst layer. The refractory three-dimensional structure generally has partition walls that define a plurality of gas flow paths that penetrate from the gas inlet end face to the gas outlet end face, and the catalyst layer is supported on the partition walls. The type and size of the refractory three-dimensional structure are not particularly limited, and any known structure in the field of exhaust gas purification catalysts can be appropriately adopted. A honeycomb support is preferably used as the refractory three-dimensional structure. Examples of honeycomb support include monolith honeycomb support, metal honeycomb support, and plug honeycomb support for particulate filters. The material of the honeycomb support is preferably a heat-resistant metal such as cordierite, silicon carbide, silicon nitride, stainless steel, or an Fe-Cr-Al alloy.

[0038] The honeycomb carrier is manufactured by extrusion molding or by winding sheet-like elements. The shape of the gas passage openings (cell shape) may be any of hexagonal, rectangular, square, triangular, and corrugated. A cell density (number of cells / unit cross-sectional area) of 100 to 1200 cells / square inch (15.5 to 186 cells / square centimeter) is sufficient for use, and preferably 200 to 900 cells / square inch (31 to 139.5 cells / square centimeter).

[0039] The length of the fire-resistant three-dimensional structure along the gas flow path (length of the partition wall) is preferably more than 15 mm and not more than 1000 mm, more preferably 30 mm or more and 500 mm or less, and even more preferably 40 mm or more and 300 mm or less.

[0040] [Catalyst layer] The catalyst layer is supported on the partition walls of the fire-resistant three-dimensional structure. The catalyst layer essentially contains the selective catalytic reduction catalyst material. The content of the selective catalytic reduction catalyst material in the catalyst layer per liter of the fire-resistant three-dimensional structure is preferably 50 to 500 g / L, more preferably 70 to 300 g / L, and even more preferably 100 to 200 g / L. If the content of the selective catalytic reduction catalyst material is within the above range, the NOx purification performance can be further improved.

[0041] The catalyst layer may further contain other components in addition to the selective catalytic reduction catalyst material, as long as the effects of the present invention are not significantly impaired. The other components that can be contained in the catalyst layer are the same as the "other components" described above in <Selective catalytic reduction catalyst material>.

[0042] The content of other components in the catalyst layer is not particularly limited, but is preferably 0 to 5 mass%, more preferably 0 to 3 mass%, even more preferably 0 to 1 mass%, and particularly preferably 0 mass%, relative to 100 mass% of the total mass of the catalyst layer (i.e., the catalyst layer consists only of the selective catalytic reduction catalyst material).

[0043] <Method for producing selective catalytic reduction catalyst> The method for producing the selective catalytic reduction catalyst is not particularly limited, but is preferably the following method. That is, a method for producing a selective catalytic reduction catalyst according to another embodiment of the present invention comprises preparing a slurry containing the inorganic oxide precursor and the Cu-supported CHA-type zeolite (hereinafter also referred to as "slurry preparation step (1)" or "step (1)"); and applying the slurry to the refractory three-dimensional structure to form a coating film, and drying and firing the coating film (hereinafter also referred to as "catalyst layer formation step (2)" or "step (2)"). Each step of the production method according to this embodiment will be described in detail below.

[0044] [Slurry preparation step (1)] In step (1), a slurry containing an inorganic oxide precursor and Cu-supported CHA-type zeolite is prepared.

[0045] The inorganic oxide precursor is not particularly limited as long as it constitutes an inorganic oxide after firing, but is preferably a colloidal solution (sol) of a hydrate. For example, when the inorganic oxide is zirconia, the zirconia precursor is preferably a colloidal solution of zirconia hydrate (zirconia sol). Furthermore, when the inorganic oxide is a mixture of zirconia and yttria, the zirconia precursor and the yttria precursor are preferably a colloidal solution of zirconia hydrate (zirconia sol) and a colloidal solution of yttria hydrate (yttria sol), respectively.

[0046] Average particle size of inorganic oxide hydrate (D 50 The average particle diameter (D) is not particularly limited, but is preferably 0.5 to 10,000 nm, more preferably 1 to 8,000 nm, and even more preferably 3 to 5,000 nm. 50 When the average particle diameter (D) is 0.5 nm or more, the interaction between Cu and the metal oxide is reduced, and the elution of Cu is suppressed, which is preferable. 50 ) is preferably 10,000 nm or less, since this facilitates slurry processability. 50 ) are values ​​measured by the method described in the Examples below.

[0047] According to the studies of the present inventors, as will be shown in the examples described later, when the inorganic oxide is composed of only zirconia, the average particle diameter (D 50It has been found that as the average particle diameter (D ) of the zirconia precursor increases, the NOx purification performance of the selective catalytic reduction catalyst tends to improve. The mechanism by which such an effect is achieved is not completely clear, and the present invention is not bound by any theory, but it is speculated that the increase in particle diameter reduces the interaction with Cu, thereby suppressing the elution of Cu. Therefore, in a method for producing a selective catalytic reduction catalyst according to a preferred embodiment of the present invention, the inorganic oxide is the single metal oxide, the precursor of the single metal oxide is a zirconia precursor, and the average particle diameter (D 50 ) exceeds 500 nm. The average particle diameter of the zirconia precursor (D 50 ) is more preferably 600 to 7000 nm, further preferably 1000 to 6000 nm, particularly preferably 3000 to 5500 nm, and most preferably 4000 to 5000 nm.

[0048] The average particle size of Cu-loaded CHA-type zeolite in the slurry (D 50 The average particle diameter (D) is not particularly limited, but is preferably 1 to 5 μm, more preferably 1.5 to 4.5 μm, and even more preferably 2 to 4 μm. 50 If the average particle diameter (D) is 1 μm or more, gas diffusibility is improved, which is preferable. 50 In this specification, the average particle diameter (D 50 ) is the value measured using a laser diffraction / scattering particle size analyzer (PSA1090 manufactured by Anton Paar).

[0049] The solvent (dispersion medium) contained in the slurry is not particularly limited, but examples thereof include water (pure water, ultrapure water, deionized water, distilled water, etc.), lower alcohols such as ethanol and 2-propanol, and organic alkaline aqueous solutions. Of these, water and lower alcohols are preferred, and water is more preferred. The amount of solvent in the slurry is not particularly limited, but is preferably an amount such that the proportion of solids in the slurry (solids mass concentration) is preferably 5 to 60 mass%, more preferably 10 to 50 mass%.

[0050] If necessary, the pH of the slurry may be adjusted to a desired range. Examples of acids used to adjust the pH include acetic acid, hydrochloric acid, sulfuric acid, nitric acid, and carbonic acid. Examples of bases used to adjust the pH include ammonia, tetraethylammonium hydroxide, sodium hydroxide, potassium hydroxide, sodium carbonate, and potassium carbonate. These may be used alone or in combination of two or more.

[0051] [Catalyst layer formation process (2)] In step (2), the slurry is applied to the refractory three-dimensional structure to form a coating film, and the coating film is dried and fired.

[0052] The slurry can be applied to the fire-resistant three-dimensional structure by a known method such as wash coating. The amount of the slurry applied is such that the amount of each component of the catalyst layer falls within the aforementioned range.

[0053] Known methods can also be used as appropriate for drying and baking the coating film formed on the partition walls by the above-mentioned coating. In this specification, "drying" refers to removing the solvent contained in the coating film, and "baking" refers to further treating the coating film from which the solvent has been removed at a high temperature to adhere each component to the partition walls. The drying conditions are not particularly limited, but are preferably carried out in air at a temperature of 50°C or higher but lower than 300°C, more preferably 80°C or higher but 200°C, for a period of 5 minutes or longer but 10 hours or shorter, and more preferably 15 minutes or longer but 8 hours or shorter. The baking conditions are also not particularly limited, but are preferably carried out in air at a temperature of 300°C or higher but 1200°C, more preferably 400°C or higher but 700°C, for a period of 10 minutes or longer but 10 hours or shorter, and more preferably 30 minutes or longer but 5 hours or shorter.

[0054] <Method for purifying nitrogen oxides> According to yet another aspect of the present invention, there is provided a method for purifying nitrogen oxides, comprising contacting the selective catalytic reduction catalyst with a mixed gas containing exhaust gas containing nitrogen oxides (NOx) emitted from an internal combustion engine and ammonia (NH3).

[0055] Examples of internal combustion engines include diesel engines, diesel hybrid engines, engines that use natural gas or the like as fuel, gasoline engines, etc. Among these, diesel engines are preferred.

[0056] Nitrogen oxides (NOx) include nitric oxide (NO), nitrogen dioxide (NO2), nitrogen trioxide (NO3), nitrous oxide (dinitrogen monoxide) (N2O), dinitrogen trioxide (N2O3), dinitrogen tetroxide (N2O4), and dinitrogen pentoxide (N2O5).

[0057] Ammonia (NH3) can be mixed with the exhaust gas upstream of the selective catalytic reduction catalyst. Ammonia may be mixed with the exhaust gas in its original form, or it may be mixed with the exhaust gas as an ammonia precursor (e.g., urea water) and converted to ammonia during contact with the selective catalytic reduction catalyst.

[0058] The space velocity (GHSV) of the mixed gas is not particularly limited, but is preferably 1,000 h -1 Over 500,000h -1 Less than or equal to 5,000 hours -1 Over 200,000h -1 The linear velocity of the gas is also not particularly limited, but is preferably 0.1 m / sec or more and 8.5 m / sec or less, and more preferably 0.2 m / sec or more and 6.7 m / sec or less.

[0059] Although the embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments and can be modified in various ways within the scope of the claims. Furthermore, the embodiments described in this specification can be combined in any manner to form other embodiments.

[0060] The following embodiments are also included within the scope of the present invention: a selective catalytic reduction catalyst material according to claim 1 having the features of claim 2; a selective catalytic reduction catalyst material according to claim 1 or 2 having the features of claim 3; a selective catalytic reduction catalyst material according to any one of claims 1 to 3 having the features of claim 4; a selective catalytic reduction catalyst material according to any one of claims 1 to 4 having the features of claim 5; a selective catalytic reduction catalyst material according to any one of claims 1 to 5 having the features of claim 6; a selective catalytic reduction catalyst comprising the selective catalytic reduction catalyst material according to any one of claims 1 to 6 and having the features of claim 7; a method for producing the selective catalytic reduction catalyst according to claim 7, which production method has the features of claim 8; and the production method according to claim 8 having the features of claim 9. [Example]

[0061] The present invention will be described in more detail below with reference to examples. However, the technical scope of the present invention is not limited to the following examples. Unless otherwise specified, each operation was carried out under the conditions of room temperature (25°C) and a relative humidity of 40% RH or more and 50% RH or less.

[0062] <Average particle size of precursor (D 50 )> A colloidal solution was prepared by adding 37.7 parts by mass of an aqueous acetic acid solution (concentration 99% by mass) to water in an amount such that the solids concentration of the final colloidal solution would be 20% by mass, and dispersing 62.3 parts by mass of the sol (precursor dispersed in water) to be measured in this. When the average particle diameter (D50) was 0.1 μm or more, the average particle diameter (D50) was measured by the Fraunhofer diffraction method using a laser diffraction / scattering particle diameter measuring device (PSA1090 manufactured by Anton Paar). 50 When the average particle diameter (D50) was less than 0.1 μm, the average particle diameter (D) was measured in 90° dynamic light scattering mode using a molecular size analyzer (Malvern, Zetasizer Lab) that uses dynamic light scattering. 50 ) was measured.

[0063] <Production of selective catalytic reduction catalyst> [Example 1] (Preparation of Slurry) 10.59 parts by mass of an aqueous acetic acid solution (concentration: 99% by mass) was added to water in an amount such that the solid content of the finally obtained slurry would be 45% by mass, and a water-dispersed zirconia sol (average particle diameter (D 50 ) 3.36 nm, solid content 40 mass % 18 mass parts were dispersed, and further Cu-supported CHA-type zeolite (Cu / Al (molar ratio) = 0.38, SiO2 / Al2O3 (molar ratio) = 24, average particle diameter (D 50 ) 3 μm, the same below) were added and mixed so that the mass ratio of the calcined Cu-supported CHA-type zeolite:ZrO 2 was 132:18, and slurry A was obtained.

[0064] (Catalyst Preparation) Slurry A was applied to a cordierite support (diameter 24 mm, length 43 mm, cylindrical, 400 cells / square inch (1 inch = 25.4 mm), wall thickness 4 mil (1 mil = 0.0254 mm), cell shape square; the same applies below) so that the loading after calcination would be 150 g / L, and the support was dried at 90°C for 20 minutes and then calcined at 550°C for 30 minutes. This resulted in catalyst A, in which a catalytic layer containing selective catalytic reduction catalyst material A consisting of Cu-supported CHA-type zeolite and zirconia (ZrO2) was supported on the cordierite support. The parameter E of the inorganic oxide (zirconia) contained in selective catalytic reduction catalyst material A was E = 1 × 1.33 = 1.33.

[0065] [Example 2] (Preparation of Slurry) Instead of the water-dispersed zirconia sol, a water-dispersed mixed sol containing zirconia and yttria in a mass ratio of 80:20 (average particle diameter (D 50 Slurry B (mass ratio of Cu-supported CHA-type zeolite:ZrO2:Y2O3 after calcination was 132:14.4:3.6) was obtained in the same manner as in Example 1, except that 4530 nm of zeolite and 40% by mass of solids were used.

[0066] (Catalyst Preparation) The slurry was applied to a cordierite carrier, dried, and fired in the same manner as in Example 1, except that slurry B was used instead of slurry A. As a result, catalyst B was obtained, in which a catalytic layer containing selective catalytic reduction catalyst material B consisting of Cu-supported CHA-type zeolite, zirconia (ZrO2), and yttria (YO3) was supported on the cordierite carrier. The parameter E of the inorganic oxide (a mixture of zirconia and yttria) contained in selective catalytic reduction catalyst material B was E = 0.8 × 1.33 + 0.2 × 1.22 = 1.31.

[0067] [Example 3] (Preparation of Slurry) Instead of the water-dispersed zirconia sol, a water-dispersed mixed sol containing zirconia and yttria in a mass ratio of 50:50 (average particle diameter (D 50 Slurry C (mass ratio of Cu-supported CHA-type zeolite:ZrO2:Y2O3 after calcination was 132:9:9) was obtained in the same manner as in Example 1, except that a sintered product having a viscosity of 3690 nm and a solid content of 50 mass% was used.

[0068] (Catalyst Preparation) The slurry was applied to a cordierite carrier, dried, and fired in the same manner as in Example 1, except that slurry C was used instead of slurry A. As a result, catalyst C was obtained, in which a catalytic layer containing selective catalytic reduction catalyst material C consisting of Cu-supported CHA-type zeolite, zirconia (ZrO2), and yttria (YO3) was supported on the cordierite carrier. The parameter E of the inorganic oxide (a mixture of zirconia and yttria) contained in selective catalytic reduction catalyst material C was E = 0.5 × 1.33 + 0.5 × 1.22 = 1.28.

[0069] [Example 4] (Preparation of Slurry) Instead of the water-dispersed zirconia sol, a water-dispersed mixed sol containing zirconia and lanthana in a mass ratio of 80:20 (average particle diameter (D 50Slurry D (mass ratio of Cu-supported CHA-type zeolite:ZrO2:La2O3 after firing was 132:14.4:3.6) was obtained in the same manner as in Example 1, except that 6.14 nm of Cu was used, and solid content was 40 mass%).

[0070] (Catalyst Preparation) The slurry was applied to a cordierite carrier, dried, and fired in the same manner as in Example 1, except that slurry D was used instead of slurry A. As a result, catalyst D was obtained, in which a catalytic layer containing selective catalytic reduction catalyst material D consisting of Cu-supported CHA-type zeolite, zirconia (ZrO2), and lanthana (La2O3) was supported on the cordierite carrier. The parameter E of the inorganic oxide (a mixture of zirconia and lanthana) contained in selective catalytic reduction catalyst material D was E = 0.8 × 1.33 + 0.2 × 1.10 = 1.28.

[0071] [Comparative Example 1] (Preparation of Slurry) Instead of the water-dispersed zirconia sol, a water-dispersed mixed sol containing zirconia and lanthana in a mass ratio of 50:50 (average particle diameter (D 50 Slurry E (mass ratio of Cu-supported CHA-type zeolite:ZrO2:La2O3 after calcination was 132:9:9) was obtained in the same manner as in Example 1, except that a sintered powder having a viscosity of 7740 nm and a solid content of 40 mass% was used.

[0072] (Catalyst Preparation) The slurry was applied to a cordierite carrier, dried, and fired in the same manner as in Example 1, except that slurry E was used instead of slurry A. As a result, catalyst E was obtained, in which a catalytic layer containing selective catalytic reduction catalyst material E consisting of Cu-supported CHA-type zeolite, zirconia (ZrO2), and lanthana (La2O3) was supported on the cordierite carrier. The parameter E of the inorganic oxide (a mixture of zirconia and lanthana) contained in selective catalytic reduction catalyst material E was E = 0.5 × 1.33 + 0.5 × 1.10 = 1.22.

[0073] Comparative Example 2 (Preparation of Slurry) Instead of the water-dispersed zirconia sol, a water-dispersed alumina sol (average particle diameter (D 50 Slurry F (mass ratio of Cu-supported CHA-type zeolite to Al2O3 after firing was 132:18) was obtained in the same manner as in Example 1, except that 37.6 nm of Cu-supported CHA-type zeolite and 20 mass% of Al2O3 were used.

[0074] (Catalyst Preparation) The slurry was applied to a cordierite carrier, dried, and fired in the same manner as in Example 1, except that slurry F was used instead of slurry A. As a result, catalyst F was obtained, in which a catalytic layer containing selective catalytic reduction catalyst material F made of Cu-supported CHA-type zeolite and alumina (Al2O3) was supported on the cordierite carrier. The parameter E of the inorganic oxide (alumina) contained in selective catalytic reduction catalyst material F was E = 1 × 1.61 = 1.61.

[0075] [Example 5] Instead of the water-dispersed zirconia sol, a water-dispersed zirconia sol (average particle diameter (D 50 (Preparation of slurry) and (production of catalyst) were carried out in the same manner as in Example 1, except that a zeolite having a particle size of 59 nm and a solid content of 20 mass% was used, thereby obtaining catalyst G in which a catalytic layer containing selective catalytic reduction catalyst material G (parameter E=1.33) made of Cu-supported CHA-type zeolite and zirconia (ZrO) was supported on a cordierite carrier.

[0076] Comparative Example 3 (Preparation of Slurry) Instead of the water-dispersed zirconia sol, a water-dispersed mixed sol containing zirconia and titania in a mass ratio of 50:50 (average particle diameter (D 50 Slurry H (mass ratio of Cu-supported CHA-type zeolite:ZrO2:TiO2 after firing was 132:9:9) was obtained in the same manner as in Example 1, except that 210 nm of zeolite powder and 55 mass% of solid content were used.

[0077] (Catalyst Preparation) The slurry was applied to a cordierite carrier, dried, and fired in the same manner as in Example 1, except that slurry H was used instead of slurry A. As a result, catalyst H was obtained, in which a catalytic layer containing selective catalytic reduction catalyst material H consisting of Cu-supported CHA-type zeolite, zirconia (ZrO2), and titania (TiO2) was supported on the cordierite carrier. The parameter E of the inorganic oxide (mixture of zirconia and titania) contained in selective catalytic reduction catalyst material H was E = 0.5 × 1.33 + 0.5 × 1.54 = 1.44.

[0078] Comparative Example 4 (Preparation of Slurry) Instead of the water-dispersed zirconia sol, a water-dispersed mixed sol (average particle diameter (D 50 Slurry I (mass ratio of Cu-supported CHA-type zeolite:ZrO2:TiO2 after firing was 132:1.8:16.2) was obtained in the same manner as in Example 1, except that 620 nm of zeolite, 80% by mass of solids, was used.

[0079] (Catalyst Preparation) The slurry was applied to a cordierite carrier, dried, and fired in the same manner as in Example 1, except that slurry I was used instead of slurry A. As a result, catalyst I was obtained, in which a catalytic layer containing selective catalytic reduction catalyst material I composed of Cu-supported CHA-type zeolite, zirconia (ZrO2), and titania (TiO2) was supported on the cordierite carrier. The parameter E of the inorganic oxide (mixture of zirconia and titania) contained in selective catalytic reduction catalyst material I was E = 0.1 × 1.33 + 0.9 × 1.54 = 1.52.

[0080] Comparative Example 5 (Preparation of Slurry) Instead of the water-dispersed zirconia sol, a water-dispersed mixed sol containing alumina and titania in a mass ratio of 50:50 (average particle diameter (D 50Slurry J (mass ratio of Cu-supported CHA-type zeolite:Al2O3:TiO2 after firing was 132:9:9) was obtained in the same manner as in Example 1, except that 270 nm of zeolite powder and 70 mass% of solid content were used.

[0081] (Catalyst Preparation) The slurry was applied to a cordierite carrier, dried, and fired in the same manner as in Example 1, except that slurry J was used instead of slurry A. As a result, catalyst J was obtained, in which a catalytic layer containing selective catalytic reduction catalyst material J composed of Cu-supported CHA-type zeolite, alumina (Al2O3), and titania (TiO2) was supported on the cordierite carrier. The parameter E of the inorganic oxide (a mixture of alumina and titania) contained in selective catalytic reduction catalyst material J was E = 0.5 × 1.61 + 0.5 × 1.54 = 1.58.

[0082] [Example 6] (Preparation of Slurry) Instead of the water-dispersed zirconia sol, a water-dispersed mixed sol containing alumina and ceria in a mass ratio of 30:70 (average particle diameter (D 50 Slurry K (mass ratio of Cu-supported CHA-type zeolite:Al2O3:CeO2 after firing was 132:5.4:12.6) was obtained in the same manner as in Example 1, except that 23.9 nm of Cu-supported CHA-type zeolite, 80 mass% solids content was used.

[0083] (Catalyst Preparation) The slurry was applied to a cordierite carrier, dried, and fired in the same manner as in Example 1, except that slurry K was used instead of slurry A. As a result, catalyst K was obtained, in which a catalytic layer containing selective catalytic reduction catalyst material K composed of Cu-supported CHA-type zeolite, alumina (Al2O3), and ceria (CeO2) was supported on the cordierite carrier. The parameter E of the inorganic oxide (a mixture of alumina and ceria) contained in selective catalytic reduction catalyst material K was E = 0.3 × 1.61 + 0.7 × 1.12 = 1.27.

[0084] [Example 7] (Preparation of Slurry) Instead of the water-dispersed zirconia sol, a water-dispersed mixed sol containing zirconia and ceria in a mass ratio of 50:50 (average particle diameter (D 50 Slurry L (mass ratio of Cu-supported CHA-type zeolite:ZrO2:CeO2 after firing was 132:9:9) was obtained in the same manner as in Example 1, except that 9.66 nm of Cu, 70% by mass of solid content was used.

[0085] (Catalyst Preparation) The slurry was applied to a cordierite carrier, dried, and fired in the same manner as in Example 1, except that slurry L was used instead of slurry A. As a result, catalyst L was obtained, in which a catalytic layer containing selective catalytic reduction catalyst material L composed of Cu-supported CHA-type zeolite, zirconia (ZrO2), and ceria (CeO2) was supported on the cordierite carrier. The parameter E of the inorganic oxide (mixture of zirconia and ceria) contained in selective catalytic reduction catalyst material L was E = 0.5 × 1.33 + 0.5 × 1.12 = 1.23.

[0086] [Example 8] (Preparation of Slurry) Instead of the water-dispersed zirconia sol, a water-dispersed mixed sol containing alumina and lanthana in a mass ratio of 35:65 (average particle diameter (D 50 Slurry M (mass ratio of Cu-supported CHA-type zeolite:Al2O3:La2O3 after firing was 132:6.3:11.7) was obtained in the same manner as in Example 1, except that 37.6 nm of Cu, 50% by mass of solid content was used.

[0087] (Catalyst Preparation) The slurry was applied to a cordierite carrier, dried, and fired in the same manner as in Example 1, except that slurry M was used instead of slurry A. As a result, catalyst M was obtained, in which a catalytic layer containing selective catalytic reduction catalyst material M consisting of Cu-supported CHA-type zeolite, alumina (Al2O3), and lanthana (La2O3) was supported on the cordierite carrier. The parameter E of the inorganic oxide (a mixture of alumina and lanthana) contained in selective catalytic reduction catalyst material M was E = 0.35 × 1.61 + 0.65 × 1.10 = 1.28.

[0088] [Example 9] (Preparation of Slurry) Instead of the water-dispersed zirconia sol, a water-dispersed mixed sol containing zirconia and yttria in a mass ratio of 20:80 (average particle diameter (D 50 Slurry N (mass ratio of Cu-supported CHA-type zeolite:ZrO2:Y2O3 after calcination was 132:3.6:14.4) was obtained in the same manner as in Example 1, except that 8.30 nm of zeolite, 50% by mass of solid content was used.

[0089] (Catalyst Preparation) The slurry was applied to a cordierite carrier, dried, and fired in the same manner as in Example 1, except that slurry N was used instead of slurry A. As a result, catalyst N was obtained, in which a catalytic layer containing selective catalytic reduction catalyst material N composed of Cu-supported CHA-type zeolite, zirconia (ZrO2), and yttria (YO3) was supported on the cordierite carrier. The parameter E of the inorganic oxide (a mixture of zirconia and yttria) contained in selective catalytic reduction catalyst material N was E = 0.2 × 1.33 + 0.8 × 1.22 = 1.24.

[0090] [Example 10] As a zirconia precursor, water-dispersed zirconia sol (average particle diameter (D 50A catalyst O having a Cu-supported CHA-type zeolite and a selective catalytic reduction catalyst material O (parameter E=1.33) composed of zirconia (ZrO2) and a catalyst layer supported on a cordierite carrier was used.

[0091] [Example 11] As a zirconia precursor, water-dispersed zirconia sol (average particle diameter (D 50 ) 13.06 nm, solid content 40 mass % was used. Except for this, (slurry preparation) and (catalyst production) were carried out in the same manner as in Example 1, to obtain catalyst P in which a catalytic layer containing selective catalytic reduction catalyst material P (parameter E = 1.33) composed of Cu-supported CHA-type zeolite and zirconia (ZrO2) was supported on a cordierite carrier.

[0092] [Example 12] As a zirconia precursor, water-dispersed zirconia sol (average particle diameter (D 50 ) 1010 nm, solid content 40 mass % was used. Except for this, (slurry preparation) and (catalyst production) were carried out in the same manner as in Example 1, to obtain catalyst Q in which a catalytic layer containing selective catalytic reduction catalyst material Q (parameter E = 1.33) composed of Cu-supported CHA-type zeolite and zirconia (ZrO2) was supported on a cordierite carrier.

[0093] [Example 13] As a zirconia precursor, water-dispersed zirconia sol (average particle diameter (D 50 ) 3040 nm, solid content 40 mass % was used. Except for this, (slurry preparation) and (catalyst production) were carried out in the same manner as in Example 1, to obtain catalyst R in which a catalytic layer containing selective catalytic reduction catalyst material R (parameter E = 1.33) made of Cu-supported CHA-type zeolite and zirconia (ZrO2) was supported on a cordierite carrier.

[0094] [Example 14] As a zirconia precursor, water-dispersed zirconia sol (average particle diameter (D50 ) A material with a particle size of 4250 nm and a solid content of 40% by mass was used. Except for this, the same procedures as in Example 1 were carried out for (slurry preparation) and (catalyst preparation), and a catalyst S was obtained, on which a catalyst layer containing a selective catalytic reduction catalyst material S (parameter E = 1.33) composed of Cu-supported CHA zeolite and zirconia (ZrO2) on a cordierite carrier was supported.

[0095] <NOx Purification Performance Evaluation> The catalyst was installed in an evaluation apparatus, and the gas of Composition 1 shown in Table 2 below was supplied to the reaction line and pretreated at 500 °C for 10 minutes. Then, the catalyst was cooled to 200 °C. Next, the gas of Composition 2 shown in Table 2 below was supplied to the reaction line, and after 5 minutes, the gas of Composition 3 shown in Table 2 below was supplied to the reaction line at a space velocity (SV) of 150,000 h -1 to carry out the SCR reaction. After confirming that the NO concentration in the gas on the catalyst outlet side became constant, the NO conversion rate (%) was calculated from the NO concentration C1 [volume ppm] in the gas on the catalyst inlet side and the NO concentration C2 [volume ppm] in the gas on the catalyst outlet side using the formula: {(C1 - C2) / C1} × 100. The results are shown in Table 3 below.

[0096]

Table 2

[0097] ] [[ID=]]<0

Table 3

[0098] <0 As shown in Table 1, according to the present invention, the NOx purification performance can be improved. In particular, it can be seen that when the parameter E is within the range exceeding 1.22 and less than 1.33, even more excellent NOx purification performance is exhibited.

[0099] Also, in the case where the inorganic oxide is only zirconia, it can be seen that when the average particle diameter (D 50 ) of the zirconia precursor exceeds 500 nm, the NOx purification performance is improved.

Claims

1. A selective catalytic reduction catalyst material comprising a Cu-supported CHA-type zeolite and an inorganic oxide, the inorganic oxide is a single metal oxide or a metal oxide mixture containing at least two single metal oxides; a selective catalytic reduction catalyst material, wherein the inorganic oxide has a parameter E calculated by the following formula 1 that is greater than 1.22 and less than 1.35; [Equation 1] In the above formula 1, E ｋ is the electronegativity of the metal of the single metal oxide k in the inorganic oxide, and x ｋ is the ratio of the mass of the single metal oxide k to the total mass of the inorganic oxide, and n is the number of types of single metal oxides constituting the inorganic oxide, and is an integer of 1 or more.

2. The material for a selective catalytic reduction catalyst according to claim 1 , wherein the parameter E is less than 1.

33.

3. The selective catalytic reduction catalyst material according to claim 2 , wherein the parameter E is 1.27 or more and 1.28 or less.

4. the inorganic oxide is a metal oxide mixture containing at least two single metal oxides; 2. The selective catalytic reduction catalyst material according to claim 1, wherein the metal oxide mixture comprises at least two selected from the group consisting of zirconia, alumina, ceria, yttria, and lanthana.

5. 5. The selective catalytic reduction catalyst material according to claim 4, wherein the metal oxide mixture is composed of zirconia and yttria, zirconia and lanthana, ceria and alumina, ceria and zirconia, or alumina and lanthana.

6. 2. The selective catalytic reduction catalyst material according to claim 1, wherein the inorganic oxide is contained in an amount of 3 to 20 mass % based on the total mass of the inorganic oxide and the Cu-supported CHA-type zeolite.

7. A selective catalytic reduction catalyst having a catalyst layer comprising the material for selective catalytic reduction catalyst according to any one of claims 1 to 6 on a fire-resistant three-dimensional structure.

8. preparing a slurry containing the inorganic oxide precursor and the Cu-supported CHA-type zeolite; Applying the slurry to the fire-resistant three-dimensional structure to form a coating; drying and baking the coating; The method for producing the selective catalytic reduction catalyst according to claim 7, comprising:

9. the inorganic oxide is a single metal oxide, the precursor of the single metal oxide is a zirconia precursor; The average particle diameter (D ５０ 9. The method of claim 8, wherein the thickness of the first and second electrodes is greater than 500 nm.

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