JP2002336706A - Catalyst structure for cleaning exhaust gas and method for manufacturing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a high performance catalyst structure for cleaning exhaust gas low in cost capable of more enhancing catalytic reaction efficiency. SOLUTION: In the catalyst structure 3 for cleaning exhaust gas constituted by laminating a large number of catalyst elements 1, each of which is obtained by supporting a catalyst component on a reticulated substrate having a large number of strip-like projections 5 provided thereto at a predetermined pitch so as to form an uneven shape having a stairs-shaped, corrugated board-shaped or U-shaped cross section, at a lamination pitch 2 so that the strip-like projections 5 cross each other between the adjacent catalyst elements 1, strip-like parts 4 not carrying catalyst component through which meshes pierce partially or entirely are provided to the parts opposed to the strip-like projections 5 of the adjacent catalyst elements 1.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an exhaust gas treatment catalyst structure and a method for producing the same, and more particularly to a method for efficiently reducing nitrogen oxides (hereinafter referred to as NOx) in exhaust gas with ammonia (NH ₃ ). And a method for producing the same.

[0002]

2. Description of the Related Art NO in smoke exhausted from power plants and the like
x is a causative substance such as acid rain, and as an effective method for removing it, for example, a flue gas denitration method in which selective catalytic reduction treatment is performed using NH ₃ as a reducing agent.

[0003] A denitration catalyst applied to such a selective catalytic reduction denitration method is usually formed into a honeycomb shape, a plate shape or the like, and various production methods have been proposed. Among them, a metal thin plate is subjected to metal lath processing and then subjected to aluminum spraying, a woven or non-woven fabric made of ceramic fiber is used as a substrate, a catalyst component is applied thereto, and a pressed catalyst is processed into an element having a waveform. The catalyst structure formed by laminating a large number of such layers has excellent features such as low ventilation loss and is hardly clogged with dust and combustion ash of coal, and is currently used in many cases for denitration of exhaust gas from thermal power boilers. Japanese Patent Application Laid-Open No. 54-7918 discloses such a prior art.
8 and JP-A-59-73053.

As a technique capable of promoting the catalytic reaction by disturbing the flow of the gas to be treated, there are known a stepwise or corrugated shaped catalyst body of the present inventor, and a flat weave. A catalyst structure in which cloth or a net-like material such as a metal plate having a hole penetrating the front and back is alternately laminated, or a belt-like projection having a stepped or corrugated shape is provided on a plate-shaped catalyst having a hole penetrating the front and back. There is a catalyst structure which is alternately stacked so that the belt-like projections intersect, and the catalyst structure has a structure in which the gas to be treated is disturbed through the openings of the catalyst and the mesh to form a catalyst structure. Is promoted, the reaction rate is dramatically improved, and high catalytic performance is obtained.

[0005]

In recent years, in order to improve the performance of an exhaust gas denitration apparatus, the thickness of a catalyst has been reduced.
Efforts have been made in many areas to reduce ventilation losses and raw material costs. In the field of denitrification of exhaust gas from coal-fired boilers, which used to use a catalyst with a large pitch between catalysts at a low gas flow rate, the demand for compact denitration equipment that increased the gas flow rate and narrowed the catalyst pitch was also increasing. Is growing.

[0006] The above-mentioned unknown technique of the present inventor matches recent trends in that the reaction is promoted by disturbing the gas flow, but the contact efficiency between the gas to be treated and the catalyst is increased. However, there has been a demand for the development of a catalyst structure for exhaust gas treatment and a method for producing the same, which can be produced by a low-cost and simple method.

An object of the present invention is to provide a high-performance, low-cost exhaust gas treatment catalyst structure capable of disturbing the flow of a gas to be treated and further promoting a catalytic reaction, and a method for producing the same. To provide.

[0008]

Means for Solving the Problems To solve the above problems, the present inventor conducted various studies on a method for supporting a catalyst component on a catalyst substrate, a method for laminating a plate-like catalyst, and the like. By adopting a method of supporting the catalyst component instead of the conventional coating and rolling method and employing a dipping method in a slurry containing the catalyst component, cost reduction by reducing the number of steps, and the amount of catalyst used, for example, from 700 g / m ² to 400 g / m ² , and in the case of CU (Cross Undulated) shape, regular openings are formed in the catalyst element, and high performance can be achieved by turbulence of gas. As a result, a net-like substrate provided with band-shaped protrusions at a predetermined pitch so that the cross section becomes a stepped shape, a corrugated plate shape, and a U-shaped shape crosses each other between adjacent substrates where the band-shaped protrusions are adjacent to each other. like A substrate structure with several stacked, for example 1.0~4.5mm the longitudinal direction of the mesh size of the mesh substrate of the substrate structure, the short-side direction of the mesh width 1.0
~ 2.5mm, the laminating pitch between the reticulated substrates is 2.0 ~
When it is 5.0 mm, the viscosity is 1.5 to 2.3 Pa · s.
By immersing in a catalyst component-containing slurry adjusted to (1500 to 2300 cP), a part or all of a mesh penetrates a portion of the mesh substrate facing a belt-like projection of an adjacent mesh substrate. By forming a portion and drying and baking it under predetermined conditions, the required amount of supported catalyst and the number of manufacturing steps are reduced,
The inventors have found that a catalyst structure can be obtained at low cost and in which the catalyst contact efficiency is remarkably improved by three-dimensional turbulence of the gas flow, and have reached the present invention.

That is, the invention claimed in the present application is as follows. (1) A catalyst element in which a catalyst component is carried on a net-like substrate provided with a large number of band-shaped projections at a predetermined pitch so as to have a step-like, corrugated, or U-shape cross section, In an exhaust gas treatment catalyst structure in which a large number of protrusions intersect each other between adjacent catalyst elements, the catalyst element has a portion of a mesh or a mesh at a portion opposed to the band-shaped protrusion of the adjacent catalyst element. A catalyst structure for exhaust gas treatment, comprising a strip-shaped catalyst component-unsupported portion which is entirely penetrated. (2) The exhaust gas treatment catalyst according to (1), wherein the mesh substrate is a metal lath substrate, and the catalyst component contains at least one of oxides of titanium, vanadium, molybdenum, and tungsten. Structure.

(3) A catalyst element in which a catalyst component is carried on a net-like substrate provided with a large number of band-shaped projections at a predetermined pitch so as to have a step-like, corrugated or U-shaped cross section. In the method for manufacturing a catalyst structure for exhaust gas treatment in which a plurality of strip-shaped projections are stacked so as to cross each other between adjacent catalyst elements, the angles of the strip-shaped projections provided at the predetermined pitch with respect to a substrate edge are respectively different. The two types of reticulated substrates are stacked on each other so that the strip-shaped protrusions of the reticulated substrate cross each other between adjacent substrates to form a substrate structure, and the substrate structure is adjusted to a predetermined viscosity. Immersed in the slurry containing the catalyst component,
In a portion opposed to the band-shaped projection of the adjacent net-like substrate, part or all of the mesh penetrates, and after supporting the catalyst component so as to leave a band-shaped catalyst component unsupported portion, drying and firing are performed. A method for producing a catalyst structure for treating exhaust gas.

(4) The mesh width of the mesh substrate in the long side direction of the above-mentioned board structure is 1.0 to 4.5 mm, the mesh width of the short side direction is 1.0 to 2.5 mm, and the lamination pitch between the mesh substrates. Is 2.0 to 5.0 mm, the viscosity of the catalyst component-containing slurry is 1.5 to 2.3 Pa · s (1500 to 23 Pa).
00cP). The method for producing a catalyst structure for exhaust gas treatment according to (3) above, wherein

(5) A metal lath substrate is used as the reticulated substrate, and a slurry containing at least one of titanium, vanadium, molybdenum and tungsten oxides is used as the catalyst component-containing slurry. ) Or (4), a method for producing a catalyst structure for treating exhaust gas. (6) The method according to any one of (3) to (5), wherein the viscosity of the catalyst component-containing slurry is adjusted to adjust the ratio of through holes in the belt-shaped catalyst component-unsupported portion. Method for producing a catalyst structure for treating exhaust gas.

[0013]

FIG. 1 is an explanatory view showing a catalyst structure according to one embodiment of the present invention. FIG. 2 is a partially enlarged view showing a metal lath substrate as a mesh substrate applied to the present invention. FIG. 3 is an explanatory diagram showing a situation in which a catalyst component is supported on a metal lath substrate as a net-like substrate of the substrate structure, leaving a catalyst component unsupported portion.

In FIG. 1, the catalyst structure for exhaust gas treatment comprises a catalyst element 1 in which a catalyst component is carried on a metal lath substrate provided with strip-shaped projections 5 at a predetermined pitch so that the cross section becomes uneven. Is a catalyst structure for exhaust gas treatment, wherein a number of the protrusions 5 are stacked so as to cross each other between the adjacent catalyst elements 1, and a portion of the catalyst element 1 facing the strip-shaped protrusion 5 of the adjacent catalyst element, This is provided with a strip-shaped catalyst component-unsupported portion 4 penetrating part or all of the mesh, and 6 is a gas flow to be treated.

[0015] Such a catalyst structure for treating exhaust gas is manufactured as follows. That is, when a large number of metal lath substrates each having a mesh length 8 in the lath length direction of 4.0 mm and a mesh width 9 in the short direction shown in FIG. 2 of 2.0 mm are stacked, the stacking pitch becomes, for example, 4.0 mm. Two kinds of strip-shaped projections 5 having different heights are provided at different angles with respect to the edges of the metal lath substrate, and the two kinds of metal lath boards are crossed between adjacent boards. The substrate structure is formed by laminating a large number of every other substrate structure, and this substrate structure has a predetermined viscosity, for example, 1.8 Pa · s (1800 c
By immersing in the slurry containing the catalyst component adjusted in P), as shown in FIG. 3, the catalyst slurry between the metal lath substrate 1 and the portion of the metal lath substrate 1 facing the strip-shaped projection 5 adjacent thereto. Slurry that covers the mesh of the sandwiched portion of the metal lath substrate by the tension from the band-shaped projections 5 (upper band-shaped projections shown in FIG. 3) located on both upper and lower sides of the metal lath substrate because the metal lath substrate tends to become spherical due to surface tension. Is pulled up and down, and the slurry at that part cannot maintain the surface tension enough to cover the mesh, and a part or all of the mesh penetrates from the front to the back, forming a catalyst component unsupported part, and the other part of the catalyst The components are supported so as to close the mesh. Therefore, by drying and calcining the catalyst-supporting structure under predetermined conditions, a strip-shaped catalyst in which part or all of the mesh penetrates a portion of the catalyst element facing the strip-shaped projection of the adjacent catalyst element. An exhaust gas treatment catalyst structure provided with a component-unsupported portion is obtained. The metal lath substrate 1 shown in FIG.
7 mm.

According to this embodiment, after the metal lath substrate is subjected to surface roughening treatment or application of a catalyst component, the mesh size and the laminating conditions of the metal lath substrate can be adjusted without passing through a step of penetrating the mesh using compressed air. A catalyst structure having a catalyst component-unsupported portion, in which part or all of a mesh penetrates a portion of a metal lath substrate facing an adjacent strip-shaped projection simply by immersing the substrate structure in a slurry having a predetermined viscosity prepared as described above. The body is obtained. This catalyst structure can cause a three-dimensional gas flow turbulence through an open mesh portion while maintaining the catalyst surface area as compared with the conventional catalyst structure, so that the catalytic reaction efficiency is significantly improved. . In addition, by adopting the method of immersing the catalyst component-containing slurry in the substrate structure as a method of supporting the catalyst component on the metal lath substrate, the amount of the supported catalyst component can be significantly reduced as compared with the conventional coating or rolling method. A low mass and low cost catalyst structure is obtained.

In the present invention, as the net-like substrate, for example, a metal lath substrate obtained by processing a metal lath into a metal lath, or a substrate made of a woven or nonwoven fabric made of ceramic fibers is used. The metal lath substrate may be rolled by rolling or pressing. As the catalyst component, one containing at least one of oxides of titanium, vanadium, molybdenum and tungsten is used. Preferably, for example, titanium oxide is used as a main component, and vanadium (V), molybdenum (Mo) ) And / or those containing an oxide of tungsten (W).

In the present invention, as the cross-sectional shape of the metal lath substrate, for example, as shown in FIGS. 4A to 4E, an uneven shape such as a stepped shape, a corrugated shape, and a U-shape is exemplified. , And other uneven shapes. In the present invention, two types of net-like substrates constituting the substrate structure are used, in which the angles of the strip-like projections provided at a predetermined pitch with respect to the edge of the substrate are different. However,
A plurality of substrates having the same angle may be prepared, and alternately turned upside down and stacked, thereby forming a substrate structure.

In the present invention, by adjusting the laminating pitch of the substrate, the mesh width, and the viscosity of the slurry containing the catalyst component, a part or all of the mesh is formed on the portion of the mesh substrate facing the band-like projection of the adjacent mesh substrate. A catalyst structure having a belt-shaped unsupported portion of the catalyst component through which is penetrated is prepared.

In the present invention, the mesh width of the metal lath substrate constituting the substrate structure in the longitudinal direction is 1.0 to 4.5 mm,
When the mesh width in the short direction is 1.0 to 2.5 mm and the lamination pitch between the substrates is 2.0 to 5.0 mm, the viscosity of the catalyst component-containing slurry may be 1.5 to 2.3 Pa · s. It is preferably, and more preferably, 1.8 to 2.1 Pa · s. When the viscosity of the slurry is 2.4 Pa · s or more, all the meshes cannot be closed or immersed, and when the viscosity is 1.4 Pa · s or less, the required amount of supported catalyst cannot be secured.

In the present invention, by adjusting the viscosity of the catalyst component slurry between 1.5 and 2.3 Pa · s,
The ratio of the mesh penetrating the front and back, that is, the ratio of the through holes in the catalyst component unsupported portion can be adjusted. Examples of those that increase the viscosity of the slurry include antifoaming agents, titanium oxide, and inorganic fibers.
For example, a surfactant, silica sol, oxalic acid and the like can be mentioned. These components may be used alone or in combination of two or more. In the present invention, the drying conditions of the substrate structure supporting the catalyst component are, for example, at room temperature in the air for 20 to 30 hours, and the firing conditions after drying are, for example, 500 ° C. for 2 hours.

[0022]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, specific embodiments of the present invention will be described. Example 1 306.5 g of ammonium metavanadate and 275.9 g of molybdenum trioxide were mixed in 2759 g of water and mixed with about 20
After stirring for 1 hour, 100 μm length of inorganic fiber milled fiber 11 was added to a solution containing 1432 g of silica sol.
23 g and 2625 g of titanium oxide were added to obtain a viscosity of 1.
A catalyst component slurry of 8 Pa · s (1800 cP) was obtained.

On the other hand, the plate thickness is 0.64 mm, and the opening ratio is 74.0.
%, A metal lath having a mesh length of 4.0 mm and a mesh width of 2.0 mm in the short direction was sandwiched between the molds, and FIG.
And a band-shaped protrusion having a lamination pitch of 4.0 mm when laminating the substrates is formed by a pair of two opposite sides of the metal lath substrate.
Molded in large numbers at an angle of 0 °, width 498 mm, length 5
A 00 mm metal lath substrate was obtained. This was turned upside down on every other sheet, laminated, and then baked at 400 ° C. for 10 minutes to obtain a substrate structure by degreasing.

This substrate structure is immersed in the catalyst component slurry to leave an unsupported portion of the catalyst component, in which a part or all of the mesh penetrates a portion of the metal lath substrate facing the band-shaped projection of the adjacent metal lath substrate. Thus, a catalyst-carrying structure carrying a catalyst component was obtained. The structure was dried in the air at room temperature for 25 hours, and then calcined at 500 ° C. for 2 hours to obtain a catalyst structure for exhaust gas treatment.

[0025] Titanium oxide 1.2kg of ammonium molybdate in Comparative Example 1 specific surface area of _{^{270m 2 / g ((NH 4}} ) 6 · Mo 7 O 24 · 4H 2
O) 0.25 kg, ammonium metavanadate 0.23
kg, 0.3 kg of oxalic acid, and water were added to form a paste. To this was added 15 wt% of kaolin-based inorganic fiber (trade name: kao wool), and the mixture was further kneaded to obtain a paste having a water content of 30.5%.

The above paste was applied to the same metal lath base material as in Example 1 using a pair of rolling rollers on the openings and the surface of the base material to form a catalyst element. This catalyst element was sandwiched between molds to have the same shape as in Example 1,
Every other sheet was turned upside down, laminated, and fired at 500 ° C. for 2 hours to obtain a catalyst structure.

Comparative Example 2 To the catalyst component slurry of Example 1, 131 g of titanium oxide and 0.85 g of a surfactant were added, and the viscosity was 2.4 Pa · s (24
00cP) was obtained. The substrate structure obtained in the same manner as in Example 1 was immersed therein, dried at room temperature for 25 hours, and fired at 500 ° C. for 2 hours to obtain a catalyst structure in which the mesh of the catalyst element was completely closed. For the catalyst structures of Example 1, Comparative Examples 1 and 2, the denitration performance was measured under the conditions shown in Table 1. Table 2 shows the test results and the mass ratio of the catalyst structure.
Are shown together. In the table, the activity ratio is a ratio of the volume-based overall reaction rate constant, and the value of Comparative Example 1 was set to 1.

[0028]

[Table 1]

[0029]

[Table 2] From the results in Table 2, it can be seen that the catalyst structure of Example 1 uses a smaller amount of catalyst than the catalyst structure of Comparative Example 1, and the catalyst activity is significantly improved. In contrast, the catalyst structure of Comparative Example 1 has a larger mass than that of Example 1,
Moreover, it can be seen that the catalytic activity is low.

The reason why the catalyst structure of Example 1 has improved catalytic activity as compared with Comparative Example 1 is as follows.
By providing a belt-shaped catalyst component unsupported portion through which a part or all of the mesh penetrates at a portion facing the belt-shaped projection, the gas to be processed flows through the catalyst component unsupported portion and is disturbed. This is probably because the contact efficiency with the catalyst was improved. The reason why the mass of the catalyst structure of Example 1 was reduced as compared with Comparative Example 1 is that the method of loading the catalyst on the catalyst structure (metal lath substrate) of Comparative Example 1 was a coating and rolling method. In contrast to the structure in which the catalyst component closed the entire mesh of the substrate, Example 1 is considered to be due to supporting the catalyst component by immersing the substrate structure in the catalyst slurry.

In Comparative Example 2, the amount of supported catalyst was reduced as in Example 1. However, since the viscosity of the catalyst slurry was not appropriate, the unsupported portion of the catalyst component penetrating part or all of the mesh was used. It is considered that the activity ratio was not sufficiently increased as compared with Example 1 because no network was formed and all the meshes were closed.

[0032]

According to the invention described in claim 1 of the present application,
Since the required amount of catalyst component is reduced, and the gas stream to be treated is three-dimensionally disturbed to improve the contact efficiency with the catalyst,
A low-mass, low-cost exhaust gas treatment catalyst structure is obtained,
The catalytic reaction efficiency is significantly improved. According to the invention as set forth in claim 2 of the present application, in addition to the effects of the above invention, a catalyst structure for exhaust gas denitration, which requires a small amount of catalyst and has excellent denitration activity, can be obtained. According to the invention described in claim 3 of the present application, the amount of catalyst used and the number of manufacturing steps are reduced, and a low-cost and highly active catalyst structure for exhaust gas treatment can be manufactured.

According to the invention described in claim 4 of the present application, a strip-shaped catalyst component-unsupported portion is formed at a portion of each net-like substrate facing the strip-like projection of an adjacent net-like substrate, and the gas flow to be processed is tertiary. Because of the original flow, an exhaust gas treatment catalyst structure having high catalytic reaction efficiency can be obtained as in the above invention. According to the invention described in claim 5 of the present application, in addition to the effects of the above invention, a catalyst structure for exhaust gas denitration that is excellent in denitration activity at low cost can be manufactured. According to the invention as set forth in claim 6 of the present application, in addition to the effects of the above invention, a catalyst structure for exhaust gas treatment that meets the processing conditions by adjusting the degree of three-dimensional turbulence of gas can be obtained.

[Brief description of the drawings]

FIG. 1 is an explanatory view of an exhaust gas treatment catalyst structure according to an embodiment of the present invention.

FIG. 2 is a partially enlarged explanatory view of a metal lath substrate used in the present invention.

FIG. 3 is an explanatory diagram showing a situation where an unsupported portion of a catalyst component is formed.

FIG. 4 is an explanatory diagram showing a cross-sectional shape of a mesh substrate applied to the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Metal lath substrate (catalyst element), 2 ... catalyst pitch, 3 ... catalyst structure, 4 ... catalyst component unsupported portion (through-hole of mesh), 5 ... belt-like projection, 6 ... gas flow to be treated, 7 ... lath Feed pitch, 8: Lath long mesh width, 9: Lath short mesh width.

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) B01J 37/02 301 B01J 37/02 301D F01N 3/10 A F01N 3/10 3/28 301P 3/28 301 B01D 53/36 102D (72) Inventor Koichi Yokoyama 3-36 Takara-cho, Kure-shi, Hiroshima Pref. Inside Bureok Hitachi Kure Research Institute (72) Inventor Naomi Imada 3-36 Takara-cho, Kure-shi Hiroshima Pref. Inside the laboratory (72) Inventor Tetsuro Hikino 6-9 Takara-cho, Kure-shi, Hiroshima Babcock Hitachi Kure Works F-term (reference) 3G091 AB01 GA09 GA16 GA18 GA20 GB01X GB10W 4D048 AA06 AB02 AC04 BA07Y BA10X BA13Y BA23X BA26X BA27Y BA39Y BA41X BB02 BB12 BB16 4G069 AA03 AA08 AA11 BA13A BA13B BA17 BB04A BC50A BC54A BC54B BC59A BC59B BC60A CA02 CA08 CA13 EA20 EA23 EA25 EB04 EB10 EB12X EB12Y EB14Y EC29 FA03 FA04 FA06 FB15 FB16

Claims (6)

[Claims] 1. A catalyst element in which a catalyst component is carried on a net-like substrate provided with a large number of band-shaped projections at a predetermined pitch so as to have a step-like, corrugated, and U-shaped cross section. In an exhaust gas treatment catalyst structure in which a large number of the belt-shaped projections are stacked so as to intersect with each other between adjacent catalyst elements, a portion of the catalyst element facing the belt-shaped projection of the adjacent catalyst element has a mesh. A catalyst structure for exhaust gas treatment, comprising a strip-shaped catalyst component-unsupported portion that penetrates all or part of the catalyst structure. 2. The net-like substrate is a metal lath substrate,
The exhaust gas treatment catalyst structure according to claim 1, wherein the catalyst component contains at least one of oxides of titanium, vanadium, molybdenum, and tungsten. 3. A catalyst element in which a catalyst component is carried on a net-like substrate provided with a large number of belt-like projections at a predetermined pitch so as to have a step-like, corrugated, or U-shape in cross section. In the method for manufacturing a catalyst structure for exhaust gas treatment in which a plurality of strip-shaped projections are stacked so as to cross each other between adjacent catalyst elements, angles of the strip-shaped projections provided at the predetermined pitch with respect to a substrate edge are respectively different. Two types of net-like substrates were stacked in a row so that the strip-shaped projections of the net-like substrate crossed each other between adjacent substrates to form a substrate structure, and the substrate structure was adjusted to a predetermined viscosity. The catalyst component is immersed in the slurry containing the catalyst component, and the catalyst component is formed so as to leave a strip-shaped catalyst component-unsupported portion through which a part or all of the mesh penetrates in a portion of each mesh substrate facing the strip projection of the adjacent mesh substrate. A method for producing a catalyst structure for exhaust gas treatment, comprising drying, calcining, and drying after carrying the components. 4. The mesh width of the mesh substrate in the long side direction of the board structure in the long side direction is 1.0 to 4.5 mm, the mesh width in the short side direction is 1.0 to 2.5 mm, and the laminating pitch between the mesh substrates is 4. When the viscosity is 2.0 to 5.0 mm, the viscosity of the slurry containing the catalyst component is 1.5 to 2.3 Pa · s (1500 to 230 Pa).
0 cP). The method for producing a catalyst structure for exhaust gas treatment according to claim 3, wherein the pressure is 0 cP). 5. A metal lath substrate as the reticulated substrate, and a slurry containing at least one of titanium, vanadium, molybdenum and tungsten oxides is used as the catalyst component-containing slurry. 5. The method for producing a catalyst structure for exhaust gas treatment according to item 4. 6. The ratio of through-holes in the belt-shaped portion not carrying a catalyst component is adjusted by adjusting the viscosity of the slurry containing the catalyst component.
The method for producing a catalyst structure for exhaust gas treatment according to any one of the above.