Exhaust gas purification catalyst device

Abstract

A catalytic device for purifying exhaust gas, comprising a substrate and a catalytic coating layer on the substrate, wherein the catalytic coating layer contains Fe-BEA type zeolite and Fe2O3 particles. Exhaust gas purification catalytic device.

Description

[Technical Field]

[0001] The present invention relates to an exhaust gas purification catalyst device. [Background technology]

[0002] A process called selective catalytic reduction (SCR) is known as a method for purifying nitrogen oxides (NOx) contained in exhaust gases emitted from internal combustion engines such as automobiles, especially diesel engines. The SCR process uses ammonia as a reducing agent to selectively reduce NOx using a catalyst.

[0003] In the SCR process, N2O may be produced as a by-product of the reduction and purification of NOx. N2O is known to be a greenhouse gas, and it is desirable to reduce its emissions as much as possible.

[0004] It is known that Cu-zeolite (particularly Cu-CHA) and Fe-zeolite (particularly Fe-BEA) can be used in combination to suppress NO emissions in the SCR process. However, Fe-BEA has the problem of being poisoned by hydrocarbons (HC) in the exhaust gas, resulting in a decrease in activity.

[0005] Furthermore, in order to regenerate HC-poisoned Fe-BEA, it is possible to desorb HC by heat treatment. However, since desorption of HC from poisoned Fe-BEA requires heating at extremely high temperatures, there is a concern that the activity may decrease due to destruction of the BEA zeolite structure.

[0006] Therefore, in the prior art, several means have been proposed for suppressing HC poisoning of Fe-BEA in SCRs containing Fe-BEA.

[0007] For example, Patent Document 1 proposes that the catalytic layer of an exhaust gas purification catalytic device be made into a two-layer structure, with Fe-BEA placed in the lower layer and Cu-zeilite placed in the upper layer, thereby reducing the frequency of contact between Fe-BEA and HC. [Prior art documents] [Patent documents]

[0008] [Patent Document 1] Japanese Patent Application Laid-Open No. 2016-221517 Summary of the Invention [Problem to be solved by the invention]

[0009] In the prior art including Patent Document 1, the effect of suppressing HC poisoning of Fe-BEA is insufficient. In addition, once Fe-BEA is poisoned with HC, the regeneration temperature is extremely high, which is a problem in that an effective poisoning regeneration process cannot be established.

[0010] The object of the present invention is to provide an exhaust gas purification catalyst device which has a low 50% HC purification temperature, so that even if HC is adsorbed, it is easily removed, and HC poisoning of Fe-BEA is effectively suppressed, and at the same time, has a high 50% NH3 purification temperature, so that NH3 is not oxidized but is used as a reducing agent for NOx purification, thereby demonstrating high NOx purification performance. [Means for solving the problem]

[0011] The present invention is as follows.

[0012] Aspect 1: An exhaust gas purification catalyst device including a substrate and a catalyst coating layer on the substrate, The catalyst coating layer contains Fe-BEA type zeolite and Fe2O3 particles. Exhaust gas purification catalytic device. Aspect 2: The catalytic device for purifying exhaust gas according to Aspect 1, wherein the Fe2O3 particles have an average particle size D50 of less than 0.90 μm. Aspect 3: The amount of the Fe2O3 particles is 0.10 parts by mass with respect to 100 parts by mass of the Fe-BEA zeolite. Department Super 10.00 mass Department 2. The catalytic device for exhaust gas purification according to claim 1, wherein the total mass of the catalytic converter is less than 1000 MPa. Aspect 4: The amount of the Fe2O3 particles is 0.10 parts by mass relative to 100 parts by mass of the Fe-BEA zeolite Department Super 10.00 mass Department 3. The catalytic device for exhaust gas purification according to claim 2, wherein the total mass of the catalytic converter is less than 1000 MPa. <Aspect 5> The amount of Fe in the Fe-BEA zeolite, calculated as Fe2O3, is 1.0 mass% or more and 10.0 mass% or less, based on the total mass of the Fe-BEA zeolite. A catalytic device for purifying exhaust gas according to any one of aspects 1 to 4. Aspect 6: The catalytic device for purifying exhaust gas according to any one of Aspects 1 to 4, wherein the Fe-BEA zeolite has an SAR of 20.0 or less. Aspect 7: The catalytic device for purifying exhaust gas according to any one of Aspects 1 to 4, wherein the catalytic coating layer is substantially free of platinum group elements. Aspect 8: The catalytic device for purifying exhaust gas according to any one of Aspects 1 to 4, wherein the catalyst coating layer has a single layer structure. Aspect 9: The exhaust gas purification catalyst device according to aspect 1, wherein the catalyst coating layer is composed of a first catalyst coating layer containing Fe-BEA type zeolite and Fe2O3 particles, and a second catalyst coating layer not containing Fe-BEA type zeolite or Fe2O3 particles. Aspect 10: The exhaust gas purification catalyst device according to Aspect 9, wherein the second catalyst coating layer contains one or two selected from platinum and palladium. Aspect 11: The exhaust gas purification catalyst device according to Aspect 9, wherein the second catalyst coating layer contains Cu-zeolite. Aspect 12 3. The exhaust gas purification catalyst device according to claim 2, wherein the catalyst coating layer comprises a first catalyst coating layer containing Fe-BEA type zeolite and Fe2O3 particles, and a second catalyst coating layer not containing Fe-BEA type zeolite and Fe2O3 particles. Aspect 13 Aspect 13. A catalytic device for purifying exhaust gas according to aspect 12, wherein the second catalyst coating layer contains one or two selected from platinum and palladium. Aspect 14 13. A catalytic device for purifying exhaust gases according to aspect 12, wherein the second catalyst coating layer comprises Cu-zeolite. Aspect 15 Aspect 4. An exhaust gas purification catalyst device according to aspect 3, wherein the catalyst coating layer comprises a first catalyst coating layer containing Fe-BEA type zeolite and Fe2O3 particles, and a second catalyst coating layer not containing Fe-BEA type zeolite and Fe2O3 particles. Aspect 16 Aspect 16. A catalytic device for purifying exhaust gases according to aspect 15, wherein the second catalyst coating layer contains one or two selected from platinum and palladium. Aspect 17 16. A catalytic device for purifying exhaust gases according to aspect 15, wherein the second catalyst coating layer comprises Cu-zeolite. Aspect 18 5. An exhaust gas purification catalyst device according to claim 4, wherein the catalyst coating layer comprises a first catalyst coating layer containing Fe-BEA type zeolite and Fe2O3 particles, and a second catalyst coating layer not containing Fe-BEA type zeolite or Fe2O3 particles. Aspect 19 Aspect 19. A catalytic device for purifying exhaust gases according to aspect 18, wherein the second catalyst coating layer contains one or two selected from platinum and palladium. Aspect 20 19. A catalytic device for purifying exhaust gas according to aspect 18, wherein the second catalyst coating layer comprises Cu-zeolite. Aspect 21: The catalyst device for purifying exhaust gas according to any one of Aspects 1 to 4 and Aspects 9 to 20, which is used as an SCR catalyst for a diesel engine. Aspect 22: The exhaust gas purification catalyst device according to any one of Aspects 10, 13, 16, and 19, which is used as an ASC catalyst for a diesel engine. Aspect 23: A method for purifying exhaust gas from a diesel engine, the method comprising purifying exhaust gas using the exhaust gas purification catalyst device according to any one of Aspects 1 to 4 and Aspects 9 to 20. Aspect 24: A catalyst system for purifying exhaust gas, comprising the catalyst device for purifying exhaust gas according to any one of Aspects 1 to 4 and Aspects 9 to 20, and an ASC device. <<Aspect 25>> The exhaust gas purification catalyst system according to Aspect 24, further comprising one or two exhaust gas purification catalyst devices selected from a DOC device and a DPF device. Aspect 26: A method for purifying exhaust gas, comprising purifying exhaust gas from a diesel engine using the exhaust gas purification catalyst system described in aspect 24. [Effects of the Invention]

[0013] According to the present invention, an exhaust gas purification catalyst device is provided which effectively suppresses poisoning by HC, has a high 50% purification temperature (T50) of NH3, and is used as a reducing agent for NOx purification without being oxidized, thereby exhibiting high NOx purification performance. DETAILED DESCRIPTION OF THE INVENTION

[0014] <Exhaust gas purification catalyst device> The exhaust gas purification catalyst device of the present invention is An exhaust gas purification catalyst device comprising a substrate and a catalyst coating layer on the substrate, The catalyst coating layer contains Fe-BEA type zeolite and Fe2O3 particles. It is an exhaust gas purification catalytic device.

[0015] In the exhaust gas purification catalyst device of the present invention, it is believed that the Fe2O3 particles added to the catalyst coating layer promote the combustion of adsorbed HC, thereby recovering the Fe-BEA from HC poisoning and maintaining a high level of SCR performance. However, the present invention is not bound by any particular theory.

[0016] The elements constituting the exhaust gas purification catalyst device of the present invention will be described below in order.

[0017] <Base material> The substrate in the catalytic converter for exhaust gas purification of the present invention may be a substrate having a plurality of cell flow paths separated by partition walls, or may be a honeycomb substrate used in conventional catalytic converters for exhaust gas purification. The partition walls of the substrate may or may not have pores that fluidly connect adjacent exhaust gas flow paths.

[0018] The constituent material of the substrate may be, for example, a refractory inorganic oxide such as cordierite or silicon carbide (SiC), or may be a metal. The substrate may be of either a straight flow type or a wall flow type.

[0019] The substrate in the manufacturing method of the exhaust gas purification catalyst device of the present invention may typically be, for example, a straight-flow type monolith honeycomb substrate made of cordierite or SiC, a wall-flow type monolith honeycomb substrate made of cordierite or SiC, a metal honeycomb substrate, or the like.

[0020] The shape of the substrate may be a cylinder, an elliptical cylinder, a polygonal pillar, or the like.

[0021] The capacity of the substrate, as an apparent volume expressed as the base area x length, may be, for example, 500 mL or more, 800 mL or more, 1.0 L or more, or 1.2 L or more, and may be, for example, 8.0 L or less, 5.0 L or less, 3.0 L or less, 2.0 L or less, 1.5 L or less, or 1.2 L or less.

[0022] <Catalyst Coating Layer> The catalyst coating layer contains Fe-BEA type zeolite and Fe2O3 particles. In order to achieve the effects of the present invention in the exhaust gas purification catalyst device of the present invention, it is desirable that the Fe-BEA type zeolite and the Fe2O3 particles be arranged in close proximity to each other. Therefore, the Fe-BEA type zeolite and the Fe2O3 particles may coexist in one layer.

[0023] (Fe-BEA type zeolite) The catalyst coating layer in the catalytic device for purifying exhaust gas of the present invention contains Fe-BEA type zeolite, which is thought to have the function of exhibiting SCR catalytic activity in the catalytic device for purifying exhaust gas of the present invention.

[0024] From the viewpoint of ensuring the development of a good SCR catalyst, the amount of Fe in the Fe-BEA zeolite in terms of Fe2O3 may be 1.0 mass% or more, 2.0 mass% or more, 3.0 mass% or more, or 4.0 mass% or more, based on the total mass of the Fe-BEA zeolite, and may be 10.0 mass% or less, 8.0 mass% or less, 7.0 mass% or less, 6.0 mass% or less, or 5.0 mass% or less.

[0025] From the viewpoint of balancing the SCR catalytic ability with ease of synthesis or availability, the SiO2 / Al2O3 ratio (SAR) of the Fe-BEA-type zeolite may be, as the ratio of the molar amount of SiO2 to the molar amount of Al2O3, 50.0 or less, 20.0 or less, 18.0 or less, 16.0 or less, 14.0 or less, 12.0 or less, or 10.0 or less, or may be 1.0 or more, 3.0 or more, 5.0 or more, 7.0 or more, or 9.0 or more.

[0026] The Fe-BEA type zeolite may be in a particulate form. The particulate Fe-BEA type zeolite may have a particle size (D50) at a cumulative mass percentage of 50% in a particle size distribution measured by a dynamic light scattering method of 0.5 μm or more, 0.7 μm or more, 1.0 μm or more, 1.2 μm or more, or 1.5 μm or more, and may be 5.0 μm or less, 4.5 μm or less, 4.0 μm or less, or 3.5 μm or less.

[0027] The amount of Fe-BEA zeolite in the exhaust gas purification catalyst device of the present invention may be, for example, 80 g / L or more and 250 g / L or less in terms of the mass of Fe-BEA zeolite per 1 L of substrate volume.

[0028] (Fe2O3 particles) The catalyst coating layer in the catalytic device for purifying exhaust gas of the present invention contains Fe2O3 particles. The Fe2O3 particles are thought to have the function of promoting the combustion of HC in the catalytic device for purifying exhaust gas of the present invention and suppressing HC poisoning of the Fe-BEA.

[0029] The Fe2O3 particles may be small particles from the viewpoint of highly active expression of the HC combustion promoting function. The particle size (D50) of the Fe2O3 particles at a cumulative mass percentage of 50% in the particle size distribution measured by dynamic light scattering may be less than 0.90 μm, 0.80 μm or less, 0.60 μm or less, 0.40 μm or less, 0.20 μm or less, or 0.10 μm or less, or may be 0.01 μm or more, more than 0.01 μm, 0.05 μm or more, 0.10 μm or more, 0.20 μm or more, or 0.30 μm or more.

[0030] The amount of the Fe2O3 particles may be more than 0.10 parts by mass, 0.50 parts by mass or more, 1.00 parts by mass or more, 1.50 parts by mass or more, 2.00 parts by mass or more, 2.50 parts by mass or more, or 3.00 parts by mass or more, relative to 100 parts by mass of the Fe-BEA-type zeolite, and may be 10.00 parts by mass or more. Department Below, 10.00 mass Department It may be less than 8.00 parts by weight or less, 6.00 parts by weight or less, 5.00 parts by weight or less, 4.50 parts by weight or less, 4.00 parts by weight or less, or 3.50 parts by weight or less.

[0031] The amount of Fe2O3 particles in the exhaust gas purification catalyst device of the present invention may be, for example, 0.08 g / L or more and 25 g / L or less in terms of the mass of Fe2O3 particles per 1 L of substrate volume.

[0032] (Other ingredients) As described above, the catalyst coating layer in the exhaust gas purification catalytic device of the present invention contains Fe-BEA type zeolite and Fe2O3 particles. The catalyst coating layer may contain components other than Fe-BEA type zeolite and Fe2O3 particles. The other components contained in the catalyst coating layer may be, for example, a zeolite other than Fe-BEA type zeolite, an inorganic oxide other than zeolite, a binder, etc. The Fe-BEA type zeolite and Fe2O3 particles, as well as the zeolite other than Fe-BEA type zeolite and the inorganic oxide other than zeolite, may contain elements such as alkali metals, alkaline earth metals, transition metals, lanthanoids, etc.

[0033] From the viewpoint of further increasing the SCR activity, the catalyst coating layer in the present invention may contain Fe-BEA type zeolite in an amount of 80 mass% or more, 85 mass% or more, 90 mass% or more, 95 mass% or more, 98 mass% or more, or 99 mass% or more relative to the total mass of zeolite contained in the catalyst coating layer, or 100 mass% of the zeolite contained in the catalyst coating layer may be Fe-BEA type zeolite.

[0034] The inorganic oxide other than zeolite may be, for example, an oxide of one or more elements selected from Al, Si, Ti, Zr, Ce, rare earth elements other than Ce, etc. From the viewpoint of further increasing the SCR activity, the amount of the inorganic oxide other than zeolite contained in the catalyst coating layer may be 20 mass % or less, 10 mass % or less, 5 mass % or less, 3 mass % or less, or 1 mass % or less relative to the total mass of the catalyst coating layer, or the catalyst coating layer may not contain any inorganic oxide other than zeolite.

[0035] The binder contained in the catalyst coating layer may be selected from, for example, silica sol, alumina sol, zirconia sol, titania sol, and the like.

[0036] The catalyst coating layer in the exhaust gas purification catalyst device of the present invention may be substantially free of platinum group elements from the viewpoint of suppressing the oxidation of NH3. Specifically, "platinum group elements" as used herein refers to platinum, palladium, and rhodium. The amount of platinum group elements in the catalyst coating layer may be 0.1 g / L or less, 0.05 g / L or less, 0.01 g / L or less, 0.005 g / L or less, or 0.001 g / L or less, in terms of the total amount of platinum group elements per 1 L of substrate volume, or the catalyst coating layer may be completely free of platinum group elements.

[0037] <Layer structure of catalyst coating layer> As mentioned above, the Fe-BEA type zeolite and the Fe2O3 particles may be contained in one layer.

[0038] In the exhaust gas purification catalyst device of the present invention, the coating amount of one catalyst coating layer containing Fe-BEA-type zeolite and Fe2O3 particles may be 80 g / L or more and 300 g / L or less in terms of the mass of the catalyst coating layer per 1 L of substrate volume, from the viewpoint of exhibiting the effects of the present invention and not causing excessive pressure loss.

[0039] The coating layer of the exhaust gas purification catalyst device of the present invention is It may have a single-layer structure having only a catalyst coating layer containing Fe-BEA type zeolite and Fe2O3 particles, The catalyst may be composed of a first catalyst coating layer containing Fe-BEA type zeolite and Fe2O3 particles, and a second catalyst coating layer not containing Fe-BEA type zeolite or Fe2O3 particles.

[0040] The second coating layer may be, for example, a catalyst layer containing one or two selected from platinum and palladium. The second coating layer containing one or two selected from platinum and palladium may function as an ammonia slip catalyst (ASC).

[0041] Alternatively, the second catalyst coating layer may be a catalyst layer containing Cu-zeolite, etc. The catalyst layer containing Cu-zeolite can function as an SCR catalyst in the same manner as the first catalyst coating layer.

[0042] The first catalyst coating layer and the second catalyst coating layer may have a laminated structure in which both layers are stacked, or may have a zone structure in which both layers are formed in order in the exhaust gas flow direction.

[0043] <Applications of exhaust gas purification catalyst devices> The catalytic device for purifying exhaust gas of the present invention is suitably used, for example, as an SCR catalytic device for a diesel engine.

[0044] <<Method for manufacturing an exhaust gas purification catalyst device>> The exhaust gas purification catalyst device of the present invention may be produced by any method as long as it has the above-mentioned configuration.

[0045] As an example of the method for manufacturing an exhaust gas purification catalyst device of the present invention, a method for manufacturing an exhaust gas purification catalyst device having a single-layer structure having only a catalyst coating layer (first catalyst coating layer) containing Fe-BEA type zeolite and Fe2O3 particles on a substrate will be described.

[0046] A single-layer catalyst device for purifying exhaust gases, having only a catalyst coating layer containing Fe-BEA-type zeolite and Fe2O3 particles on a substrate, may be produced by coating a substrate with a catalyst coating layer-forming slurry and firing the coated substrate. After coating, the coated layer may be dried, if necessary, before firing.

[0047] The substrate may be appropriately selected depending on the desired configuration of the exhaust gas purification catalyst device, and may be, for example, a straight-flow type monolith honeycomb substrate made of cordierite or SiC, a wall-flow type monolith honeycomb substrate made of cordierite or SiC, or a metal honeycomb substrate.

[0048] The substrate may be coated with the catalyst coating layer forming slurry, for example, by placing the slurry on one end face of the substrate and sucking it from the other end face of the substrate.

[0049] The catalyst coating layer forming slurry may contain, for example, Fe-BEA type zeolite and Fe2O3 particles, as well as other components used as needed, depending on the desired configuration of the catalyst coating layer. In addition to the above, the catalyst coating layer forming slurry may further contain, for example, a thickener, a pH adjuster, an antifoaming agent, etc.

[0050] Coating of the catalyst coating layer forming slurry onto the substrate, and drying and calcination after coating may each be carried out in accordance with a known method.

[0051] By the above operations, a catalytic device for purifying exhaust gases having a catalytic coating layer containing Fe-BEA-type zeolite and Fe2O3 particles on a substrate is manufactured. When the catalytic device for purifying exhaust gases has a second catalytic coating layer, this second catalytic coating layer may be formed by a known method depending on the constituent components, or by a method with appropriate modifications made by a person skilled in the art.

[0052] <Exhaust gas purification catalyst system> According to another aspect of the present invention, there is provided an exhaust gas purification catalyst system.

[0053] The exhaust gas purification catalyst device of the present invention may be used alone, but is also suitable for use as an exhaust gas purification catalyst system in combination with other exhaust gas purification catalyst devices.

[0054] The catalyst system for exhaust gas purification may include, for example, the catalyst device for exhaust gas purification of the present invention and an ammonia slip catalyst (ASC) device. In this case, the catalyst device for exhaust gas purification of the present invention and the ASC device may be arranged in this order from the upstream side to the downstream side of the exhaust gas flow.

[0055] The exhaust gas purification catalyst system may further include one or two types of exhaust gas purification catalyst devices selected from a diesel oxidation catalyst (DOC) device and a diesel particulate filter (DPF) device, in addition to the exhaust gas purification catalyst device and ASC device of the present invention.

[0056] The exhaust gas purification catalyst system is configured to, for example, The order is a DOC device, a DPF device, an exhaust gas purification catalyst device of the present invention, and an ASC device; The order of the exhaust gas purification catalyst device of the present invention, the ASC device, the DOC device, and the DPF device; In addition, an exhaust gas purification catalyst device other than those described above may be further disposed.

[0057] The ASC device, the DOC device, and the DPF device in these exhaust gas purification catalyst systems may each be appropriately selected from known exhaust gas purification catalyst devices.

[0058] <Exhaust gas purification method> According to yet another aspect of the present invention, there is provided a method for purifying exhaust gas.

[0059] The exhaust gas purification method of the present invention comprises: The exhaust gas purification catalyst device of the present invention, or An exhaust gas purification catalyst system including the exhaust gas purification catalyst device of the present invention The method includes purifying the [Example]

[0060] 1. Effect of Fe2O3 particle size In the following Examples 1 to 4 and Comparative Examples 1 to 7, the effect of adding Fe2O3 particles to Fe-BEA type zeolite and the effect of the particle size D50 of the Fe2O3 particles on the exhaust gas purification ability of an exhaust gas purification catalyst device were investigated.

[0061] (1) Manufacturing of exhaust gas purification catalyst devices Examples 1 to 6 and Comparative Examples 3, 4, 6, and 7 87.6 mass% of the zeolite material shown in Table 1, 2.7 mass% of the Fe2O3 particles shown in Table 1, and 9.7 mass% of a silica-based binder (manufactured by Nissan Chemical Industries, Ltd., product name "Snowtex NXS") were added to pure water, and monoisopropanolamine was added as a pH adjuster to adjust the pH to a range of 8 to 10. The mixture was then stirred for 30 minutes to obtain a slurry.

[0062] The resulting slurry was milled for 10 minutes to adjust the secondary particle size D50 of the zeolite material to 1.9 to 3.3 μm. Next, xanthan gum (manufactured by ADM Japan, product name "Novazan 200 Mesh") was added as a thickening polysaccharide to adjust the slurry viscosity, and the mixture was stirred for 6 hours to prepare a slurry for forming a catalyst coating layer.

[0063] The catalyst coating layer forming slurry obtained above was coated onto a straight-flow type cordierite honeycomb substrate having a diameter of 25 mm and a length of 25 mm, dried at 80°C, and then fired at 500°C for 3 hours to produce an exhaust gas purification catalyst device. The catalyst coating layer in the obtained exhaust gas purification catalyst device had a coating amount of 150 g / L, an Fe-BEA amount of 131.4 g / L, and an Fe2O3 particle amount of 4.05 g / L.

[0064] Comparative Example 1 A catalyst coating layer forming slurry was prepared in the same manner as in Example 1, except that the amounts of the zeolite material and the silica-based binder used were 90.0 mass % and 10.0 mass %, respectively, and no FeO particles were used. An exhaust gas purification catalyst device was manufactured using this slurry.

[0065] Comparative Example 2 A slurry for forming a catalyst coating layer was prepared in the same manner as in Example 1, except that 2.7 mass % of platinum oxide was used instead of Fe2O3 particles, and an exhaust gas purification catalyst device was manufactured using this.

[0066] Comparative Example 5 A slurry for forming a catalyst coating layer was prepared in the same manner as in Example 1, except that 90.0 mass% of Cu-CHA type zeolite was used as the zeolite material, the amount of silica-based binder used was 10.0 mass%, and no Fe2O3 particles were used. An exhaust gas purification catalyst device was manufactured using this slurry.

[0067] (2) Evaluation of exhaust gas purification catalyst devices The following model gases were introduced into the exhaust gas purification catalyst devices obtained in the above examples and comparative examples while the inlet gas temperature was increased from 100°C to 500°C at a rate of 20°C / min, and the 50% purification temperature T50 for HC and NOx was measured. The following model gases were also introduced while the inlet gas temperature was decreased from 500°C to 100°C at a rate of 20°C / min, and the 50% purification temperature T50 for NH3 was measured. The results are shown in Table 1.

[0068] The composition of the model gases used to examine the T50 of NH3, HC, and NOx was as follows, and the T50 of each gas was evaluated separately. The space velocity of the model gases was 60,000 h -1 (Flow rate: 12,271 mL / min).

[0069] <Composition of model gas for NH3 evaluation> NH3: 500 ppm C3H6:4,000 ppmC CO: 0.08% by volume CO2: 7% by volume O2: 8% by volume H2O: 7% by volume N2: Balance

[0070] <Composition of model gas for HC evaluation> NO: 500 ppm C3H6:4,000 ppmC CO: 0.08% by volume CO2: 7% by volume O2: 8% by volume H2O: 7% by volume N2: Balance

[0071] <Composition of model gas for NOx evaluation> NO: 250 ppm NO2: 250 ppm NH3: 500 ppm C3H6:4,000 ppmC CO: 0.08% by volume CO2: 7% by volume O2: 8% by volume H2O: 7% by volume N2: Balance

[0072] In the above, "ppmC" indicates the carbon equivalent concentration.

[0073] [Table 1]

[0074] The abbreviations for the zeolite materials in Table 1 have the following meanings: Fe-BEA: BEA-type zeolite loaded with 4.4 mass% Fe (equivalent to Fe2O3) (SAR=9.2) H-BEA: Proton-exchanged BEA-type zeolite (SAR=41.9) Cu-CHA: CHA-type zeolite carrying 5.5% by mass of CuO (SAR = 14.0)

[0075] In the above, the amounts of Fe and Cu supported in the zeolite material are each expressed as mass percentages based on the total mass of the zeolite material.

[0076] The Fe2O3 particles used had average particle diameters D50 of 0.90 μm, 0.55 μm, 0.38 μm, 0.20 μm, and 0.01 μm. The Fe2O3 particles with an average particle diameter D50 of 0.90 μm were manufactured by Toda Kogyo Co., Ltd. under the product name "SRFCA-010-1." The Fe2O3 particles with average particle diameters D50 of 0.55 μm, 0.38 μm, and 0.20 μm were prepared by milling and classifying the Fe2O3 particles (SRFCA-010-1) with an average particle diameter D50 of 0.90 μm. The Fe2O3 particles with an average particle diameter D50 of 0.01 μm were blended by directly adding the Fe2O3 particles in a sol state, which were manufactured by Taki Chemical Co., Ltd. under the product name "Bailar Fe-C10."

[0077] In Table 1, a higher 50% conversion temperature (T50) for NH3 is preferable because NH3 is less likely to be oxidized and NH3 can be more easily used as a reducing agent for NOx purification. On the other hand, a lower 50% conversion temperature (T50) for HC and NOx is preferable because HC and NOx can be purified at a lower temperature.

[0078] The results in Table 1 reveal the following:

[0079] The exhaust gas purification catalyst devices of Comparative Example 2, which used Fe-BEA as the zeolite material and supported platinum oxide on it, and Comparative Examples 5 to 7, which used Cu-CHA as the zeolite material, had significantly lower NH3 50% purification temperatures (T50) than the exhaust gas purification catalyst device of Comparative Example 1, which used Fe-BEA as the zeolite material without adding a third component, and were therefore not preferable from the perspective of using NH3 as a reducing agent for NOx purification.

[0080] Furthermore, the exhaust gas purification catalyst devices of Comparative Examples 3 and 4, in which Fe2O3 was added to H-BEA, had a higher NH3 50% purification temperature (T50) than the exhaust gas purification catalyst device of Comparative Example 1, but the HC 50% purification temperature (T50) was extremely high, and it was found that at least the HC purification performance was significantly impaired.

[0081] In contrast, the exhaust gas purification catalyst devices of Examples 1 to 6, in which Fe2O3 was added to Fe-BEA, had a higher 50% purification temperature (T50) for NH3, making it easier to use NH3 as a reducing agent for NOx purification, and had lower 50% purification temperatures (T50) for HC and NOx, demonstrating that they could purify HC and NOx at lower temperatures, compared to the exhaust gas purification catalyst device of Comparative Example 1. In particular, the exhaust gas purification catalyst devices of Examples 2 to 5, in which the average particle diameter D50 of Fe2O3 was less than 0.90 μm, had an extremely low 50% purification temperature (T50) for HC.

[0082] 2. Effect of added amount of Fe2O3 particles In the following Examples 7 to 14 and Comparative Example 8, the influence of the amount of Fe2O3 particles added on the exhaust gas purification ability of the exhaust gas purification catalyst device was investigated. It should be noted that Example 14 is a reference example.

[0083] (1) Manufacturing of exhaust gas purification catalyst devices Examples 7 to 14 and Comparative Example 8 An exhaust gas purification catalyst device was manufactured in the same manner as in Example 1, except that the above-mentioned Fe-BEA was used as the zeolite material, the above-mentioned FeO particles having an average particle size D50 of 0.38 μm were used as the FeO particles, and the amounts of both were as shown in Table 2.

[0084] (2) Evaluation of exhaust gas purification catalyst devices Using the exhaust gas purification catalyst devices obtained in the above examples and comparative examples, the space velocity of the model gas was set to 85,561 h -1 The catalyst device for purifying exhaust gas was evaluated in the same manner as in Example 1, except that the flow rate was set to 17,500 mL / min.

[0085] The results obtained are shown in Table 2.

[0086] [Table 2]

[0087] The results in Table 2 reveal the following:

[0088] The exhaust gas purification catalyst devices of Examples 7 to 14, in which Fe2O3 was added to Fe-BEA, had lower 50% conversion temperatures (T50) for HC and NOx than the exhaust gas purification catalyst device of Comparative Example 8, which used Fe-BEA without added Fe2O3, demonstrating that they could purify HC and NOx at lower temperatures. In particular, the exhaust gas purification catalyst devices of Examples 8 to 13, in which the amount of Fe2O3 used relative to Fe-BEA was more than 0.10 mass% but less than 10.00 mass%, had extremely lower 50% conversion temperatures (T50) for HC and NOx and higher 50% conversion temperatures (T50) for NH3 than the exhaust gas purification catalyst device of Comparative Example 8, and it was verified that NH3 could be easily used as a reducing agent for NOx purification and that they could purify HC and NOx at lower temperatures.

Claims

1. An exhaust gas purification catalyst device comprising a substrate and a catalyst coating layer on the substrate, the substrate is made of cordierite, The catalyst coating layer is composed of Fe-BEA type zeolite and Fe ２ O ３ containing particles, The Fe-BEA zeolite has an SAR of 5.0 or more and 14.0 or less, The Fe ２ O ３ The average particle size D50 of the particles is 0.01 μm or more and 0.90 μm or less, The Fe ２ O ３ The amount of the particles is 0.10 parts by mass or more and 8.00 parts by mass or less relative to 100 parts by mass of the Fe-BEA type zeolite. Exhaust gas purification catalytic device.

2. The Fe ２ O ３ 2. The catalytic device for purifying exhaust gas according to claim 1, wherein the particles have an average particle size D50 of more than 0.01 μm and less than 0.90 μm.

3. The Fe ２ O ３ 2. The exhaust gas purification catalyst device according to claim 1, wherein the amount of the particles is more than 0.10 parts by mass and not more than 6.00 parts by mass per 100 parts by mass of the Fe-BEA type zeolite.

4. The Fe ２ O ３ 3. The exhaust gas purification catalyst device according to claim 2, wherein the amount of the particles is more than 0.10 parts by mass and not more than 6.00 parts by mass per 100 parts by mass of the Fe-BEA type zeolite.

5. Fe in the Fe-BEA type zeolite ２ O ３ The converted Fe amount is 1.0 mass% or more and 10.0 mass% or less based on the total mass of the Fe-BEA zeolite. The exhaust gas purification catalyst device according to any one of claims 1 to 4.

6. 5. The exhaust gas purification catalyst device according to claim 1, wherein the Fe-BEA type zeolite has an SAR of 7.0 or more and 12.0 or less.

7. The catalyst coating layer does not contain any platinum group elements, or the amount of platinum group elements in the catalyst coating layer is 0.1 g / L or less as a total amount of platinum group elements in terms of metal per 1 L of the substrate volume; The exhaust gas purification catalyst device according to any one of claims 1 to 4.

8. 5. The exhaust gas purification catalyst device according to claim 1, wherein the catalyst coating layer has a single layer structure.

9. The catalyst coating layer is composed of Fe-BEA type zeolite and Fe ２ O ３ a first catalyst coating layer containing particles, and a Fe-BEA type zeolite and Fe ２ O ３ 2. The exhaust gas purifying catalyst device according to claim 1, wherein the catalyst coating layer is a second catalyst coating layer containing no particles.

10. 10. The exhaust gas purification catalyst device according to claim 9, wherein the second catalyst coating layer contains one or two types selected from platinum and palladium.

11. 10. The exhaust gas purification catalyst device according to claim 9, wherein the second catalyst coating layer contains Cu-zeolite.

12. The catalyst coating layer is composed of Fe-BEA type zeolite and Fe ２ O ３ a first catalyst coating layer containing particles, and a Fe-BEA type zeolite and Fe ２ O ３ 3. The exhaust gas purifying catalyst device according to claim 2, wherein the catalyst coating layer is a second catalyst coating layer containing no particles.

13. 13. The exhaust gas purification catalyst device according to claim 12, wherein the second catalyst coating layer contains one or two types selected from platinum and palladium.

14. 13. The exhaust gas purification catalyst device according to claim 12, wherein the second catalyst coating layer contains Cu-zeolite.

15. The catalyst coating layer is composed of Fe-BEA type zeolite and Fe ２ O ３ a first catalyst coating layer containing particles, and a Fe-BEA type zeolite and Fe ２ O ３ 4. The exhaust gas purifying catalyst device according to claim 3, wherein the catalyst coating layer is a second catalyst coating layer containing no particles.

16. 16. The exhaust gas purification catalyst device according to claim 15, wherein the second catalyst coating layer contains one or two types selected from platinum and palladium.

17. 16. The exhaust gas purification catalyst device according to claim 15, wherein the second catalyst coating layer contains Cu-zeolite.

18. The catalyst coating layer is composed of Fe-BEA type zeolite and Fe ２ O ３ a first catalyst coating layer containing particles, and a Fe-BEA type zeolite and Fe ２ O ３ 5. The exhaust gas purifying catalyst device according to claim 4, wherein the catalyst coating layer is a second catalyst coating layer containing no particles.

19. 19. The exhaust gas purification catalyst device according to claim 18, wherein the second catalyst coating layer contains one or two types selected from platinum and palladium.

20. 19. The catalytic device for purifying exhaust gas according to claim 18, wherein the second catalyst coating layer contains Cu-zeolite.

21. The exhaust gas purification catalyst device according to any one of claims 1 to 4 and 9 to 20, which is used as an SCR catalyst for a diesel engine.

22. 20. The exhaust gas purification catalyst device according to claim 10, 13, 16, or 19, which is used as an ASC catalyst for a diesel engine.

23. A method for purifying exhaust gas, comprising purifying exhaust gas from a diesel engine using the exhaust gas purification catalyst device according to any one of claims 1 to 4 and 9 to 20.

24. An exhaust gas purification catalyst system comprising the exhaust gas purification catalyst device according to any one of claims 1 to 4 and 9 to 20, and an ASC device.

25. The catalyst system for purifying exhaust gas according to claim 24, further comprising one or two kinds of catalyst devices for purifying exhaust gas selected from a DOC device and a DPF device.

26. A method for purifying exhaust gas, comprising purifying exhaust gas from a diesel engine using the catalyst system for exhaust gas purification according to claim 24.