Exhaust gas purification catalyst device

Abstract

This exhaust gas purification catalyst device includes: a base material; and a catalyst coat layer on the base material. The catalyst coat layer includes a Fe-BEA zeolite and Fe2O3 particles.

Description

Exhaust gas purification catalyst device

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

[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 of automobiles and the like, particularly diesel engines. The SCR process uses ammonia as a reducing agent to selectively reduce NOx using a catalyst.

[0003] In the SCR process, N is produced as a by-product of the reduction and purification of NOx. ２ O may be generated. ２ O is known as a greenhouse gas, and it is desirable to reduce its emissions as much as possible.

[0004] N in the SCR process ２ It is known to use a combination of Cu-zeolite (particularly Cu-CHA) and Fe-zeolite (particularly Fe-BEA) to suppress O emissions. However, Fe-BEA has the problem that its activity decreases due to poisoning by hydrocarbons (HC) in the exhaust gas.

[0005] Furthermore, in order to regenerate HC-poisoned Fe-BEA, it is conceivable to desorb HC by heat treatment. However, since desorbing 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 SCR containing Fe-BEA.

[0007] For example, Patent Document 1 proposes that the catalytic layer of an exhaust gas purification catalytic device has 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.

[0008] Japanese Patent Application Laid-Open No. 2016-221517

[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 a catalyst having a low 50% HC purification temperature, so that even if HC is adsorbed, it can be easily removed, and HC poisoning of Fe-BEA can be effectively suppressed, and NH ３ 50% purification temperature is high, and NH ３ The present invention provides an exhaust gas purification catalyst device in which the catalyst is utilized as a reducing agent for NOx purification without being oxidized, thereby exhibiting high NOx purification performance.

[0011] The present invention is as follows.

[0012] Aspect 1: A catalytic device for purifying exhaust gas, comprising a substrate and a catalytic coating layer on the substrate, wherein the catalytic coating layer is composed of Fe-BEA type zeolite and Fe ２ O ３ An exhaust gas purification catalyst device comprising the Fe particles. ２ O ３ The catalyst device for purifying exhaust gas according to Aspect 1, wherein the average particle diameter D50 of the particles is less than 0.90 μm. ２ O ３ The catalyst device for purifying exhaust gas according to Aspect 1, wherein the amount of the particles is more than 0.10 mass % and less than 10.00 mass % relative to 100 mass parts of the Fe-BEA type zeolite. ２ O ３ The catalyst device for purifying exhaust gas according to Aspect 2, wherein the amount of the particles is more than 0.10 mass % and less than 10.00 mass % relative to 100 mass parts of the Fe-BEA zeolite. ２ O ３The catalytic device for purifying exhaust gas according to any one of Aspects 1 to 4, wherein the amount of Fe converted is 1.0 mass % or more and 10.0 mass % or less, based on the total mass of the Fe-BEA type zeolite. Aspect 6: The catalytic device for purifying exhaust gas according to any one of Aspects 1 to 4, wherein the SAR of the Fe-BEA type zeolite is 20.0 or less. Aspect 7: The catalytic device for purifying exhaust gas according to any one of Aspects 1 to 4, wherein the catalyst 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 catalytic device for purifying exhaust gas according to any one of Aspects 1 to 4, wherein 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 and a second catalyst coating layer that does not contain 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: The exhaust gas purification catalyst device according to Aspect 1, wherein the catalyst coating layer contains 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 and a second catalyst coating layer that does not contain particles. Aspect 13: The exhaust gas purification catalyst device according to Aspect 12, wherein the second catalyst coating layer contains one or two selected from platinum and palladium. Aspect 14: The exhaust gas purification catalyst device according to Aspect 12, wherein the second catalyst coating layer contains Cu-zeolite. Aspect 15: The exhaust gas purification catalyst device according to Aspect 14, wherein the second catalyst coating layer contains 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 ３and a second catalyst coating layer that does not contain particles. Aspect 16: The exhaust gas purification catalyst device according to Aspect 15, wherein the second catalyst coating layer contains one or two selected from platinum and palladium. Aspect 17: The exhaust gas purification catalyst device according to Aspect 15, wherein the second catalyst coating layer contains Cu-zeolite. Aspect 18: The exhaust gas purification catalyst device according to Aspect 15, wherein the second catalyst coating layer contains 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 and a second catalyst coating layer that does not contain particles. Aspect 19: The exhaust gas purification catalyst device according to Aspect 18, wherein the second catalyst coating layer contains one or two elements selected from platinum and palladium. Aspect 20: The exhaust gas purification catalyst device according to Aspect 18, wherein the second catalyst coating layer contains Cu-zeolite. Aspect 21: The exhaust gas purification catalyst device according to any one of Aspects 1 to 4 and 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 using the exhaust gas purification catalyst device according to any one of Aspects 1 to 4 and 9 to 20. Aspect 24: A catalyst system for exhaust gas purification comprising the exhaust gas purification catalyst device according to any one of Aspects 1 to 4 and 9 to 20, and an ASC device. Aspect 25: The catalyst system for exhaust gas purification 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 from a diesel engine using the catalyst system for exhaust gas purification according to Aspect 24.

[0013] According to the present invention, poisoning by HC is effectively suppressed, and NH ３ The 50% purification temperature (T50) of ３is utilized as a reducing agent for NOx purification without being oxidized, thereby providing an exhaust gas purification catalyst device that exhibits high NOx purification performance.

[0014] The catalytic device for purifying exhaust gas of the present invention is an exhaust gas purifying catalytic device including a substrate and a catalytic coating layer on the substrate, wherein the catalytic coating layer is composed of Fe-BEA type zeolite and Fe ２ O ３ It is an exhaust gas purification catalytic device containing particles.

[0015] In the exhaust gas purification catalyst device of the present invention, Fe added to the catalyst coating layer ２ O ３ It is believed that the particles promote the combustion of adsorbed HC, thereby recovering the Fe-BEA from the HC poisoning state 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] 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 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 is made of Fe-BEA type zeolite and Fe ２ O ３ In order to achieve the effects of the present invention in the exhaust gas purification catalyst device of the present invention, Fe-BEA type zeolite and Fe ２ O ３ It is desirable that the particles are arranged close to each other. ２ O ３ The particles may coexist in one layer.

[0023] (Fe-BEA Zeolite) The catalyst coating layer in the exhaust gas purification catalyst device of the present invention contains Fe-BEA zeolite. The Fe-BEA zeolite is thought to have the function of exhibiting SCR catalyst in the exhaust gas purification catalyst device of the present invention.

[0024] Fe in Fe-BEA zeolite ２ O ３ From the viewpoint of ensuring the development of a good SCR catalyst, the converted Fe amount 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] SiO of Fe-BEA type zeolite ２ / Al ２ O ３ The ratio (SAR) of Al is determined from the viewpoint of the balance between the SCR catalytic activity and the ease of synthesis or availability. ２ O ３ SiO relative to the molar amount of ２The molar ratio of may be 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] (Fe ２ O ３ The catalyst coating layer in the exhaust gas purification catalyst device of the present invention is ２ O ３ Contains particles. ２ O ３ It is believed that the particles have the function of promoting the combustion of HC in the exhaust gas purification catalyst device of the present invention and suppressing HC poisoning of Fe-BEA.

[0029] Fe ２ O ３ The particles may be small in diameter from the viewpoint of highly active HC combustion promotion function. ２ O ３ The particle diameter (D50) at a cumulative mass percentage of 50% in the particle diameter 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] Fe ２ O ３The amount of the 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, and may be 10.00 parts by mass or less, less than 10.00 parts by mass, 8.00 parts by mass or less, 6.00 parts by mass or less, 5.00 parts by mass or less, 4.50 parts by mass or less, 4.00 parts by mass or less, or 3.50 parts by mass or less, relative to 100 parts by mass of the Fe-BEA-type zeolite.

[0031] In addition, Fe in the exhaust gas purification catalyst device of the present invention ２ O ３ The amount of particles is Fe per 1 L of substrate volume. ２ O ３ The mass of the particles may be, for example, 0.08 g / L or more and 25 g / L or less.

[0032] (Other Components) As described above, the catalyst coating layer in the exhaust gas purification catalyst device of the present invention contains Fe-BEA type zeolite and Fe ２ O ３ The catalyst coating layer contains Fe-BEA type zeolite and Fe ２ O ３ The catalyst coating layer may contain components other than the particles. The other components contained in the catalyst coating layer may be, for example, a zeolite other than the Fe-BEA type zeolite, an inorganic oxide other than the zeolite, a binder, etc. ２ O ３ The particles, zeolites other than Fe-BEA type zeolite, and inorganic oxides other than zeolites may contain elements such as alkali metals, alkaline earth metals, transition metals, and lanthanoids.

[0033] From the viewpoint of further increasing the SCR activity, the catalyst coating layer in the present invention may contain 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 of Fe-BEA zeolite 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 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 is ３ From the viewpoint of suppressing oxidation of the catalyst, the catalyst may be substantially free of platinum group elements. 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 in terms of metal 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 described above, Fe-BEA type zeolite and Fe ２ O ３ The particles may be contained in one layer.

[0038] In the exhaust gas purification catalyst device of the present invention, Fe-BEA type zeolite and Fe ２ O ３ The coating amount of one catalyst coating layer containing 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 base material 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 comprises Fe-BEA type zeolite and Fe ２ O ３The catalyst may have a single layer structure having only a catalyst coating layer containing 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 The catalyst layer may be composed of a second catalyst coating layer that does not contain 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] <Use of Exhaust Gas Purification Catalyst Device> The exhaust gas purification catalyst device of the present invention is suitably used, for example, as an SCR catalyst 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 manufactured by any method as long as it has the above-described configuration.

[0045] As an example of the method for producing an exhaust gas purification catalyst device of the present invention, a method for producing an exhaust gas purification catalyst device is described below. ２ O ３ A method for manufacturing an exhaust gas purification catalyst device having a single layer structure having only a particle-containing catalyst coating layer (first catalyst coating layer) will be described.

[0046] On the substrate, Fe-BEA type zeolite and Fe ２ O ３A single-layer catalyst device for purifying exhaust gases having only a catalyst coating layer containing particles 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 configuration of the desired exhaust gas purification catalytic device, and may be, for example, a cordierite or SiC straight-flow type monolith honeycomb substrate, a cordierite or SiC wall-flow type monolith honeycomb substrate, 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 be prepared by mixing, for example, Fe-BEA type zeolite and Fe ２ O ３ The catalyst coating layer forming slurry may further contain, in addition to the above, 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, Fe-BEA type zeolite and Fe ２ O ３ The catalyst device for purifying exhaust gases is manufactured having a catalyst coating layer containing particles. When the catalyst device for purifying exhaust gases has a second catalyst coating layer, the second catalyst 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] <<Catalyst System for Purifying Exhaust Gas>> According to another aspect of the present invention, there is provided a catalyst system for purifying exhaust gas.

[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 exhaust gas purification catalyst system may include, for example, the exhaust gas purification catalyst device of the present invention and an ammonia slip catalyst (ASC) device. In this case, the exhaust gas purification catalyst device 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 may be arranged, from upstream to downstream of the exhaust gas flow, in the following order: a DOC device, a DPF device, the exhaust gas purification catalyst device of the present invention, and an ASC device; or the exhaust gas purification catalyst device of the present invention, an ASC device, a DOC device, and a DPF device. Furthermore, an exhaust gas purification catalyst device other than those described above may also be arranged.

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

[0059] The method for purifying exhaust gas of the present invention is a method comprising purifying exhaust gas from a diesel engine using the catalytic device for exhaust gas purification of the present invention, or an exhaust gas purification catalytic system including the catalytic device for exhaust gas purification of the present invention.

[0060] 1. Fe ２ O ３ In the following Examples 1 to 4 and Comparative Examples 1 to 7, Fe-BEA type zeolite was added with Fe. ２ O ３ The effect of adding particles and Fe ２ O ３The influence of particle diameter D50 on the exhaust gas purification performance of the exhaust gas purification catalyst device was investigated.

[0061] (1) Production of an exhaust gas purification catalyst device <<Examples 1 to 6 and Comparative Examples 3, 4, 6, and 7>> 87.6 mass% of the zeolite material shown in Table 1, Fe shown in Table 1 ２ O ３ 2.7% by mass of particles and 9.7% by 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 (trade name "Novazan 200 Mesh" manufactured by ADM Japan Co., Ltd.) 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 on 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 coating amount of the catalyst coating layer in the obtained exhaust gas purification catalyst device was 150 g / L, the Fe-BEA amount was 131.4 g / L, and Fe ２ O ３ The particle amount was 4.05 g / L.

[0064] Comparative Example 1 The amounts of the zeolite material and the silica-based binder used were 90.0 mass% and 10.0 mass%, respectively, and Fe ２ O ３ A slurry for forming a catalyst coating layer was prepared in the same manner as in Example 1, except that no particles were used, and an exhaust gas purification catalyst device was manufactured using this slurry.

[0065] Comparative Example 2 Fe ２ O ３A 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 the particles, and an exhaust gas purification catalyst device was manufactured using this slurry.

[0066] Comparative Example 5: 90.0% by mass of Cu-CHA type zeolite was used as the zeolite material, the amount of silica-based binder used was 10.0% by mass, and Fe ２ O ３ A slurry for forming a catalyst coating layer was prepared in the same manner as in Example 1, except that no particles were used, and 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-mentioned respective Examples and Comparative Examples while increasing the inlet gas temperature from 100°C to 500°C at a temperature increase rate of 20°C / min, and the 50% purification temperature T50 for HC and NOx was examined. In addition, the following model gases were introduced while decreasing the inlet gas temperature from 500°C to 100°C at a temperature decrease rate of 20°C / min, and the 50% purification temperature T50 for NH ３ The 50% purification temperature T50 of the above was investigated. The results are shown in Table 1.

[0068] NH ３ The compositions of the model gases used to examine the T50 of NOx, HC, and NOx were 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] <NH ３ Composition of evaluation model gas> NH ３ : 500 ppm C ３ H ６ : 4,000 ppm C CO: 0.08 vol% CO ２ : 7% by volume O ２ : 8 volume% H ２ O: 7% by volume N ２ :balance

[0070] <Composition of model gas for HC evaluation> NO: 500 ppm C ３ H ６: 4,000 ppm C CO: 0.08 vol% CO ２ : 7% by volume O ２ : 8 volume% H ２ O: 7% by volume N ２ :balance

[0071] <Composition of model gas for NOx evaluation> NO: 250 ppm NO ２ :250ppm NH ３ : 500 ppm C ３ H ６ : 4,000 ppm C CO: 0.08 vol% CO ２ : 7% by volume O ２ : 8 volume% H ２ O: 7% by volume N ２ :balance

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

[0073]

[0074] The abbreviations of the zeolite materials in Table 1 have the following meanings: Fe-BEA: Fe ２ O ３ BEA-type zeolite carrying 4.4 mass% Fe (SAR=9.2) H-BEA: proton-exchanged BEA-type zeolite (SAR=41.9) Cu-CHA: CHA-type zeolite carrying 5.5 mass% 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] Fe ２ O ３ The particles used had average particle diameters D50 of 0.90 μm, 0.55 μm, 0.38 μm, 0.20 μm, and 0.01 μm. ２ O ３ The particles are manufactured by Toda Kogyo Co., Ltd. under the trade name "SRFCA-010-1." ２ O３ The particles are Fe particles having an average particle size D50 of 0.90 μm. ２ O ３ The particles (SRFCA-010-1) were milled and classified to prepare Fe particles with an average particle size D50 of 0.01 μm. ２ O ３ The particles are ２ O ３ The particles were contained in a sol state and were manufactured by Taki Chemical Co., Ltd. under the trade name "Bailar Fe-C10." The particles were added as they were to the mixture.

[0077] In Table 1, NH ３ The 50% purification temperature (T50) of NH ３ is difficult to oxidize, and NH ３ On the other hand, the 50% purification temperature (T50) of HC and NOx is preferably as low as possible from the viewpoint that 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, in which Fe-BEA was used as the zeolite material and platinum oxide was supported on it, and Comparative Examples 5 to 7, in which Cu-CHA was used as the zeolite material, showed a higher NH ３ The 50% purification temperature (T50) of NH ３ This was not preferable from the viewpoint of using the catalyst as a reducing agent for NOx purification.

[0080] In addition, Fe in H-BEA ２ O ３ The exhaust gas purification catalyst devices of Comparative Examples 3 and 4, to which NH was added, had a lower NH content than the exhaust gas purification catalyst device of Comparative Example 1. ３ However, the 50% purification temperature (T50) for HC became extremely high, and it was found that at least the purification performance for HC was significantly impaired.

[0081] In contrast, Fe-BEA ２ O３ The exhaust gas purification catalyst devices of Examples 1 to 6, to which NH was added, had a lower NH content than the exhaust gas purification catalyst device of Comparative Example 1. ３ The 50% purification temperature (T50) of ３ It has been verified that Fe can be easily used as a reducing agent for NOx purification, and that the 50% purification temperature (T50) of HC and NOx is low, making it possible to purify HC and NOx at a lower temperature. ２ O ３ The exhaust gas purification catalyst devices of Examples 2 to 5, in which the average particle diameter D50 of the catalyst particles was less than 0.90 μm, had an extremely low 50% HC purification temperature (T50).

[0082] 2. Fe ２ O ３ In the following Examples 7 to 14 and Comparative Example 8, the amount of Fe added was ２ O ３ The effect of the amount of particles added on the exhaust gas purification performance of the exhaust gas purification catalyst device was investigated.

[0083] (1) Production of an exhaust gas purification catalyst device <<Examples 7 to 14 and Comparative Example 8>> The above-mentioned Fe-BEA was used as the zeolite material, and Fe ２ O ３ The particles are Fe particles having an average particle size D50 of 0.38 μm. ２ O ３ An exhaust gas purifying catalyst device was produced in the same manner as in Example 1, except that particles were used and the amounts of both used were as shown in Table 2.

[0084] (2) Evaluation of the exhaust gas purification catalyst device Using the exhaust gas purification catalyst devices obtained in the above examples and comparative examples, the space velocity of the model gas was set at 85,561 h －１ The exhaust gas purification catalyst device 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]

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

[0088] Fe-BEA to Fe ２ O ３The exhaust gas purification catalyst devices of Examples 7 to 14, to which Fe was added, ２ O ３ Compared with the exhaust gas purification catalyst device of Comparative Example 8 using no Fe-BEA, the 50% purification temperature (T50) of HC and NOx was lower, and it was verified that HC and NOx can be purified at a lower temperature. ２ O ３ The exhaust gas purification catalyst devices of Examples 8 to 13 in which the amount of used is more than 0.10 mass % and less than 10.00 mass % have extremely low 50% purification temperatures (T50) of HC and NOx and low NH ３ The 50% purification temperature (T50) of NH ３ It was verified that the catalyst can be easily used as a reducing agent for NOx purification and can 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, wherein the catalyst coating layer is composed of Fe-BEA type zeolite and Fe ２ O ３ An exhaust gas purification catalytic device containing particles.

2. The above 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 less than 0.90 μm.

3. The above 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 mass % and less than 10.00 mass % relative to 100 parts by mass of the Fe-BEA type zeolite.

4. The above 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 less than 10.00 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 5. The exhaust gas purification catalyst device according to claim 1, wherein 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 type zeolite.

6. An exhaust gas purification catalyst device according to any one of claims 1 to 4, wherein the Fe-BEA type zeolite has an SAR of 20.0 or less.

7. The exhaust gas purification catalyst device according to any one of claims 1 to 4, wherein the catalyst coating layer is substantially free of platinum group elements.

8. An exhaust gas purification catalyst device according to any one of claims 1 to 4, wherein the catalyst coating layer has a single layer structure.

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

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

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

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

20. The exhaust gas purification catalyst device 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. The exhaust gas purification catalyst device according to any one of claims 10, 13, 16 and 19, which is used as an ASC catalyst for a diesel engine.

23. A method for purifying exhaust gas from a diesel engine, comprising purifying the exhaust gas using an 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 exhaust gas purification catalyst system according to claim 24, further comprising one or two exhaust gas purification catalyst devices selected from a DOC device and a DPF device.

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

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