JP2002361092A - Catalyst slurry for denitrating exhaust gas, denitration catalyst and method of producing them - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a coating slurry for a denitration catalyst, from which an exhaust gas denitration catalyst having high activity and strength is obtained, and a method of producing the same, to obtain a catalyst body having high performance using the slurry and to reduce the production cost. SOLUTION: The slurry for the exhaust gas denitration catalyst is characterized in that titanium oxide is dispersed in an aqueous solution of a compound expressed by rational formula: (NH3 )3 Mo2 V3 O15 wherein the atomic ratio of V to Mo is substantially 3:2.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a catalyst slurry for exhaust gas denitration and a method for producing the same, and more particularly to a novel method for obtaining a thin, highly active catalyst for denitration in a simple process, and the resulting method. The present invention relates to a catalyst structure.

[0002]

2. Description of the Related Art Nitrogen oxides (NOx) in flue gas emitted from power plants, various factories, automobiles, and the like are substances that cause photochemical smog and acid rain. Flue gas denitration by selective catalytic reduction using NH ₃ ) as a reducing agent is widely used mainly in thermal power plants. As the catalyst, a titanium oxide (TiO ₂ ) -based catalyst containing vanadium (V), molybdenum (Mo) or tungsten (W) as an active component is used. In particular, those containing vanadium as one of the active components are active. Not only is high, but it is also the mainstream of the current denitration catalysts because it is less deteriorated by impurities contained in the exhaust gas and can be used at lower temperatures.
No. 128681). The catalyst is usually used after being formed into a honeycomb shape or a plate shape.

[0003] The above-mentioned catalysts are prepared by kneading titanium oxide and salts of catalytically active components such as V, Mo and W together with water, followed by molding and firing (kneading method); A method of impregnating a mixture with a mixed solution of salts of catalytically active components (impregnation method), a method of coating a slurry prepared from a previously prepared catalyst component powder on a metal or ceramic substrate (Japanese Patent Laid-Open No. 50-128681, Japanese Patent Publication No. 53
No. 34195, JP-A-63-234224) are known.

[0004]

SUMMARY OF THE INVENTION Among these prior arts,
The method of coating the catalyst slurry on the metal substrate is a method in which the number of manufacturing steps is small and a highly active catalyst is easily obtained.
There was a problem that the contact strength between the substrate and the catalyst component was low, and the catalyst was easily peeled off. For this reason, attempts have been made to form a high-density catalyst coating layer by pre-calcining or finely pulverizing the catalyst component to adjust the particle size. However, it is difficult to say that sufficient strength has been obtained. In particular, when the amount of the supported catalyst is increased for the purpose of improving the performance, cracks are generated in the catalyst coating layer, and the cracks serve as a starting point, and are easily separated by vibration or thermal shock. For this reason, a relatively low amount of the catalyst component must be used, and a high-performance catalyst body could not be obtained. Further, there is also a problem that the strength of the coating layer is low, and the strength is reduced due to abrasion in exhaust gas containing dust.

An object of the present invention is to provide a denitration catalyst slurry for coating capable of obtaining a highly active and high-strength exhaust gas denitration catalyst and a method for producing the same, thereby obtaining a high-performance catalyst body and reducing the production cost. It is in.

[0006]

Means for Solving the Problems To achieve the above object, the invention claimed in the present application is as follows. (1) The chemical formula (NH ₄ ) ₃ Mo ₂ V ₃ O _{15 wherein} the atomic ratio V / Mo of vanadium to molybdenum is substantially 3/2.
A catalyst slurry for exhaust gas denitration, comprising titanium oxide dispersed in an aqueous solution of a compound represented by the formula: (2) The catalyst slurry for denitration according to (1), further comprising colloidal silica and / or inorganic fibers.

(3) Molybdenum oxide (MoO ₃ ) and ammonium metavanadate (NH ₄ VO ₃ ) are mixed with an aqueous solvent so that the atomic ratio V / Mo of vanadium to molybdenum is substantially 3/2. With the chemical formula (NH ₄ )
₃ Mo ₂ V ₃ O to obtain an aqueous solution of the compound represented by ₁₅ steps and, preparation of the catalyst slurry for exhaust gas denitration which comprises a step of dispersing titanium oxide in the aqueous solution. (4) A catalyst for exhaust gas denitration, comprising a metal or glass or ceramic catalyst substrate coated with the slurry according to (1) or (2). (5) The denitration catalyst according to (4), wherein the catalyst substrate is a mesh having a through hole, and the catalyst is coated so as to fill the mesh.

(6) The exhaust gas denitration system according to (4), wherein the catalyst substrate is a mesh substrate having through holes, and the catalyst is coated in a state where the mesh has through holes. catalyst. (7) The exhaust gas according to any one of (4) to (6), wherein the catalyst base is a flat plate, and the flat plate is formed with corrugations, irregularities, and step-like projections. DeNOx catalyst. (8) A denitration catalyst structure in which the plate-shaped denitration catalyst according to (7) is laminated, and a gas passage is formed between the denitration catalysts. (9) The method for producing a denitration catalyst slurry according to (3), wherein the catalyst is coated by immersing the plate-like catalyst in the slurry according to (1) or (2).

(10) The catalyst slurry according to (1) or (2), after previously laminating and integrating a catalyst substrate having corrugated, uneven, stepped projections formed on the surface of a flat substrate. A method for producing a catalyst structure for exhaust gas denitration, characterized in that the catalyst structure is immersed in the coating and coated with a catalyst. (11) The chemical formula (NH ₄ ) ₃ Mo ₂ V ₃ O, in which the atomic ratio V / Mo of vanadium to molybdenum is substantially 3/2.
An exhaust gas denitration catalyst comprising a compound represented by formula ₁₅ supported on titanium oxide particles.

Hereinafter, the present invention will be described in detail with reference to the drawings. 1 (a), 1 (b), 1 (c), and 1 (d) are cross-sectional views of various meshes used as a catalyst substrate in the present invention, and FIG. FIG.

[0011] The soluble Mo- used in the catalyst slurry of the present invention.
The V compound has been found by the present inventors as a result of intensive studies for solving the above-mentioned prior art, and includes ammonium metavanadate (NH ₄ Vo ₃ ) and molybdenum trioxide (Mo).
O ₃ ) at a V / Mo atomic ratio of 3/2 (practically 3 /
It is a reddish-brown substance obtained by adding to water in 1.7 to 3 / 2.3) and stirring, and the compound is characterized by having a large solubility of 170 g / liter at room temperature. To a solution of this compound, titanium oxide, if necessary, colloidal silica or inorganic fiber as a binder is added to form a slurry, and this is sprayed on the base material or the base material is immersed in the slurry. Then, a catalyst component layer is formed on the substrate.

The weight ratio of the Mo-V compound to titanium oxide used in the slurry of the present invention is more than 0 and not more than 50/100,
Preferably it is 5/100 to 25/100. Further, the amount of colloidal silica added as required exceeds 50% by weight as SiO _{2 with} respect to titanium oxide.
%, Preferably 5 to 30% by weight. Further, as the inorganic fibers, ceramic fibers such as aluminosilicate fibers, quartz glass, E glass, and the like, which are cut into fibers having a low alkali content and cut to several tens μm or less can be used. The addition amount of the inorganic fiber is 0 to 70 with respect to titanium oxide.
wt%, preferably in the range of 10-50 wt%.

Examples of the mesh used for supporting the catalyst component include stainless steel, mild steel, an aluminum metal lath, a wire mesh, and an inorganic fiber mesh woven fabric fixed with an inorganic binder.
A plate-like porous ceramic body or the like is used. As shown in FIG. 1, these base materials are formed with projections such as corrugations and irregularities in advance, and are laminated by the various lamination methods shown in FIG. 2 to form gas channels.

The catalyst of the present invention only needs to support a slurry obtained by mixing a solution of a specific soluble Mo-V compound and a titanium oxide powder on a catalyst substrate. For example, the above-mentioned colloidal silica may be replaced with another inorganic sol. Or inorganic fibers other than those described above may be used. In addition, an organic or inorganic additive can be added to control the ease with which the slurry is coated.

The amount of the catalyst carried on the catalyst substrate can be freely selected depending on the thickness of the substrate and the required performance.
In the case of a substrate having a thickness of 100 mm, it is easy to obtain a high-performance catalyst by supporting 100 to 400 g / m ² .

Next, FIG. 3 (a) shows a catalyst slurry of the present invention applied to a metal lath substrate by a coating method so as to fill the mesh-like through holes of the metal lath substrate, and dried and fired. FIG. 3 is a view showing the appearance of a catalyzed body. For comparison, FIG. 3B shows the appearance of a catalyst similarly coated using a conventional catalyst slurry containing titanium oxide, ammonium metavanadate and ammonium molybdate. FIG.
In the conventional coating catalyst of (b), it can be seen that the catalyst layer shrinks due to evaporation of water in the slurry held in the mesh of the mesh-like carrier and sintering during firing, and a large crack is generated. The cracks serve as a starting point to easily drop the catalyst from the base material, so that a high-strength catalyst cannot be obtained.In addition, the catalyst layer shrinks due to moisture evaporation and sintering to reduce the pore volume. Performance cannot be obtained.

On the other hand, the catalyst of the present invention shown in FIG. 3A uses a specific slurry containing a soluble Mo-V compound and titanium oxide as main components to form a coating layer which does not cause any cracks. Can be formed. This soluble Mo-V compound has a descriptive formula of (NH ₄ ) ₃ Mo ₂ V ₃
It is estimated to be heteropoly acid represented by O _15. In general, heteropolyacid is called an inorganic polymer, and an attempt has been made to use it as an inorganic binder.This polymer structure enhances bonding between titanium oxide particles,
It is presumed that it inhibits contraction and contributes to the generation of cracks. Further, in the case of the conventional method, when an attempt is made to increase the strength by using a sol-like substance such as colloidal silica as a binder, oxo acid ions of Mo and V are dissolved out of the catalyst component and the inorganic sol is gelled, and the binder is formed. Less effective. However, in the method of the present invention, the specific compounds that are presumed to be polyacids of Mo and V, which are active ingredients, do not gel inorganic sols such as silica sol, maintain a stable mixed state for a long time, and have a binder effect. Therefore, a strong catalyst can be obtained.

Further, in the present invention, the shrinkage in the drying process after supporting the slurry is small, and the portion where the water is scattered forms pores to promote gas diffusion into the catalyst. This makes it possible to dramatically increase the activity as compared with the conventional coating method. The catalyst of the present invention not only achieves high strength and high activity by the above-mentioned actions, but also has the following great effects on catalyst production.

In a conventional slurry for slurry coating,
The slurry state is affected by inorganic metal ions. For this reason, when it is attempted to continuously manufacture a unit in which a metallic base material is laminated, the viscosity of the slurry is gradually increased by the dissolved metal ions, and it is difficult to carry the slurry. On the other hand, since the viscosity of the slurry does not increase even if the metal substrate is immersed in the slurry of the present invention, the catalyst slurry can be continuously coated, and a production method suitable for mass production is possible.

[0020]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, specific embodiments of the present invention will be described. Example 1 A slurry obtained by adding 90 g of molybdenum trioxide (MoO ₃ ) and 100 g of ammonium metavanadate (NH ₄ VO ₃ ) to 900 g of water was gently stirred at room temperature for 20 hours to allow the two to react and completely dissolve. Chemical formula (NH ₄ ) ₃ Mo ₂
A brown clear solution containing the compound represented by V ₃ O ₁₅ was obtained. The solid content of the obtained reaction solution is 17.5% by weight.
Colloidal silica (manufactured by Nissan Chemical Industries, trade name OS sol, SiO ₂ content: 20%) was mixed and added at a weight ratio of 7: 3 to the obtained Mo-V compound solution to prepare a mixed solution. 106 g of this mixed solution was dispensed, and E glass fiber (Central Glass Co., trade name: Milled Fiber EFH-100,
10 g (length: 100 μm) (50% of titanium oxide) and 50 g of titanium oxide powder (G5, manufactured by Millennium Co., Ltd.) were added, followed by stirring to obtain a coating slurry of the present invention.

Separately, a SUS430 strip steel having a width of 500 mm and a thickness of 0.2 mm is subjected to metal lath processing to form an opening of about 2 mm.
A 100 mm square test piece was cut out from a reticulated base material of mm. After immersing this test piece in the previously prepared coating slurry, pulling it up, carrying the catalyst slurry so as to fill the mesh of the metal lath, air-drying and firing at 500 ° C. for 2 hours, the catalyst carrying amount of the present invention of 350 g / m ² was obtained. A catalyst was obtained. Comparative Example 1 1.5 kg of titanium oxide having a specific surface area of about 230 m ² / g, 86.7 g of ammonium metavanadate, 88.3 g of ammonium molybdate and 75 g of oxalic acid were charged into a kneader, and kneaded while adding water until it became clay-like. Then, the molybdenum and vanadium compounds were uniformly supported on the titanium oxide. The obtained clay-like material is extruded using a granulator at 3 mmφ.
After being extruded into a cylindrical shape, the fluidized bed was dried and calcined at 500 ° C. for 2 hours, and then a fine powder of 1 μm or less having a particle size of 50% or more was obtained using a powdering machine.

The catalyst powder 40 g, the milled fiber 8
g and 60 g of water were mixed to prepare a slurry, which was supported on a SUS430 metal lath in the same manner as in Example 1 to obtain a catalyst having a supported amount of 380 g / m ² . Comparative Example 2 Example 1 was used in place of water at the time of preparing the slurry in Comparative Example 1.
A slurry was prepared using a solution having a 3/7 weight ratio of the colloidal silica and water used in the above. However, in the case of this slurry, a sharp increase in viscosity, which is considered to be caused by gelation of colloidal silica, was observed, and a good coating catalyst was not obtained. Examples 2 to 5 The mixing ratio of the Mo-V compound and the silica sol in Example 1 was changed from 7/3 to 100/0, 85/15, 50/50 and 3.
The catalyst of the present invention was obtained in the same manner as described above except that the ratio was changed to 0/70. Examples 6 to 10 The catalysts of the present invention were prepared in the same manner as in Example 1, except that the addition amount (20%) of the milled fiber to the titanium oxide was changed to 0, 10, 30, 50, and 70 wt%.

From the catalysts obtained in Examples 1 to 10 and Comparative Example 1, strip-shaped test pieces of 10 mm × 100 mm were cut out, and the denitration performance was measured under the conditions shown in Table 1. Also,
In order to evaluate the peeling resistance of the catalysts obtained in Examples 1 to 9 and Comparative Example, the amount of catalyst peeling when a prepared 100 mm × 100 mm square catalyst plate was dropped 10 times from a height of 1 m onto a steel plate was measured. It was measured. The results obtained by these tests are shown in Table 2 together with the catalyst composition.

[0024]

[Table 1]

[0025]

[Table 2]

Each of the catalysts of the examples has higher denitration performance than the catalyst of Comparative Example 1, and the amount of peeled catalyst in the peel test is small. This clearly shows that the method of the present invention is a suitable method for obtaining a catalyst having high performance and high strength.

Further, comparing the performances of Examples 1 to 5 with the amount of peeling, the amount of peeling can be reduced by increasing the amount of silica sol added, but the denitration performance tends to decrease, and TiO ₂
When the amount of SiO ₂ added to the composition is 30 wt% or less, which is the range shown in the examples, the activity and the strength can be maintained high.

Further, when the performances of the catalysts of Examples 1 and 6 to 10 are compared, it can be seen that an increase in the amount of the milled fiber which is an inorganic fiber is effective in improving the activity and reducing the amount of peeling. However, there was a tendency that the viscosity of the slurry increased with an increase in the amount of addition, making it difficult to form a thin coating layer. Therefore, it was found that when the content of the inorganic fibers was controlled to 70 wt% or less, and preferably 50 wt% or less with respect to titanium oxide, a good coating layer was easily obtained. Example 11 In Example 1, the metal lath was immersed in the catalyst slurry, pulled up, and further blown with compressed air to remove the slurry filling the eyes of the metal lath. The obtained catalyst was dried and calcined in the same manner as in Example 1 to obtain a network catalyst of the present invention in which the metal lath surface was covered with the catalyst thinly.

Comparative Example 3 Using the catalyst slurry of Comparative Example 1, a reticulated catalyst body was obtained in the same manner as in Example 11. Example 12 Instead of the milled fiber used in Example 1, aluminosilicate fiber (fiber flux, manufactured by Toshiba Monoflux Co., Ltd.) was used, which was crushed to a length of about 0.1 mm. A catalyst was obtained. Comparative Example 4 In place of the milled fiber used in Comparative Example 1, aluminosilicate fiber (fiber flux, manufactured by Toshiba Monoflux Co., Ltd.) was crushed to a length of about 0.1 mm. Was.

Example 13 1400 E-glass fibers having a fiber diameter of 9 μm
Titania 40 on a net woven with a roughness of book / inch
%, A silica sol of 20% and a polyvinyl alcohol of 1% were impregnated with a slurry, and dried at 150 ° C. to obtain a catalyst base material. This base material was cut into a 100 mm × 100 mm square, and the catalyst of the present invention was prepared in the same manner as above except that the metal lath support of Example 1 was used. Comparative Example 5 A catalyst was prepared in the same manner as in Comparative Example 1, except that the ceramic catalyst substrate used in Example 13 was used in place of the metal lath. The denitration performance of the catalysts of Examples 11 to 13 and Comparative Examples 3 to 5 and the amount of peeling by the peeling test were measured, and the results were shown in Table 3.
It was shown to.

[0031]

[Table 3]

From the comparison of the results of Example 11 and Comparative Example 3, it can be seen that the catalyst of the present invention can maintain high activity and low exfoliation even when the mesh of the net material is open and the amount of supported catalyst is small. Example 12 and Comparative Example 4 and Example 13
From the comparison of the results of Comparative Example 5 and Comparative Example 5, it can be seen that similarly excellent catalysts can be obtained even if the inorganic fibers are other, or the reticulated carrier is a ceramic carrier other than a metal lath.

By using a soluble Mo-V compound having a specific composition as described above, a catalyst having high denitration performance and peel strength can be obtained with extremely few steps. Example 14 A catalyst unit formed by laminating a large number of metal net-like substrates was impregnated with the catalyst slurry of the present invention and coated with a catalyst. That is, the same SUS430 used in Example 1 was used.
A 2mm high corrugation is formed on the metal lath substrate
A plurality of catalyst substrates as shown in FIG. 4 were prepared. Forty-six of these were laminated on a mild steel catalyst frame to prepare a catalyst carrier unit of 150 mm square and 250 mm length.

Separately, 20 kg of a slurry having the same composition as in Example 1 was prepared, and the above-mentioned unit was immersed. After elapse of 10 minutes while oscillating the unit, the unit was pulled up from the slurry and drained. After air drying while blowing air at room temperature with a fan, 5
It was calcined at 00 ° C for 2 hours to prepare a unitary catalyst of the present invention. Comparative Example 6 The same coating catalyst was obtained by using the same metal catalyst unit as in Example 14 and the catalyst slurry used in Comparative Example 1.

When the slurries after the tests of Example 14 and Comparative Example 6 were compared, no difference was observed in the properties of the former before and after the impregnation test, but the latter was discolored to black and the viscosity was significantly increased. It was observed. This is considered to be because Fe ions eluted from the metal substrate and the metal frame to alter the catalyst and increase the viscosity. As described above, in the conventional coating method, when a metal substrate is used, the change in viscosity due to the deterioration of the slurry hinders the production of a uniform catalyst. However, in the coating method according to the present invention, soluble Mo is used.
Since the -V compound is extremely stable, the coating operation can be stably continued without deterioration due to metal ions or the like. Therefore, it is understood that the present invention is useful also from the viewpoint of catalyst production.

Using an exhaust gas denitration apparatus capable of directly filling the catalyst units obtained in Example 14 and Comparative Example 6, Table 4
The denitration performance was measured under the following conditions. When the catalyst of the present invention was used, the denitration rate was as high as 99%, but the catalyst of Comparative Example 6 was as low as 94%. High performance is also obtained when the catalyst unit is formed by coating the slurry in a unit shape.

[0037]

[Table 4]

[0038]

According to the present invention, an exhaust gas denitration catalyst having high activity and little peeling can be obtained, and the performance of the denitration apparatus can be improved. In addition, the exhaust gas denitration catalyst slurry of the present invention does not require complicated manufacturing steps such as pre-baking and pulverization, and the properties of the obtained coating slurry are stable, and the elution of inorganic ions as in the case of a metal substrate carrier. Since the properties of the carrier are not changed even if the carrier is easy to be manufactured, it is possible to mass-produce a uniform catalyst at low cost.

[Brief description of the drawings]

FIG. 1 is a sectional view of a catalyst substrate showing an example of a line formed on a flat catalyst substrate used in the present invention.

FIG. 2 is a perspective view of a catalyst structure in the case where the plate-shaped catalyst of the present invention is used by being laminated.

FIG. 3 is a view showing the appearance of the catalyst of the present invention.

FIG. 4 is a view showing schematic dimensions of a catalyst substrate used in Example 14.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) B01J 35/04 351 B01J 37/02 301M 37/02 301 F01N 3/10 A F01N 3/10 3/28 301C 3/28 301 301P B01D 53/36 102D (72) Inventor Eiji Miyamoto 3-36 Takara-cho, Kure City, Hiroshima Prefecture Babcock Hitachi Kure Laboratory (72) Inventor Tetsuro Hikino 6-9 Takaramachi, Kure City, Hiroshima Prefecture Babcock Inside Kure Works, Hitachi Co., Ltd. (72) Inventor Koichi Yokoyama 3-36, Takara-cho, Kure-shi, Hiroshima Pref. Inside Kure Research Laboratory Kure (72) Inventor Akihiro Yamada 6-9, Takara-cho, Kure-shi, Hiroshima Pref. F-term in Kure office (reference) 3G091 AA02 AB04 BA01 BA14 BA39 GA03 GA04 GA05 GA07 GA09 GA20 GB01W GB10W GB15W G B16W GB17X 4D048 AA06 AB02 BA06X BA07X BA10X BA12X BA13X BA23X BA26X BA39X BA41X BA42X BA46X BB03 BB04 BB08 BB18 4G069 AA02 AA03 AA08 BA02A BD02 BA02B BA04A BA04B BA13ABA13 BC18 BCBBC EB02 EB03 EB10 EB15Y ED03 EE06 FA01 FA02 FA03 FB06 FB15 FB16 FB23 FC02 FC08

Claims (11)

[Claims] 1. The atomic ratio of vanadium to molybdenum V / M
The chemical formula (NH ₄ ) ₃ Mo _{2 wherein} o is substantially 3/2
Exhaust gas denitration catalyst slurry, wherein the titanium oxide in an aqueous solution of the compound dispersed represented by V ₃ O _15. 2. The catalyst slurry for denitration according to claim 1, further comprising colloidal silica and / or inorganic fibers. 3. Molybdenum oxide (MoO ₃ ) and ammonium metavanadate (NH ₄ VO ₃ ) are mixed with an aqueous solvent so that the atomic ratio V / Mo of vanadium to molybdenum becomes substantially 3/2. The reaction is carried out with the chemical formula (NH ₄ ) ₃ M
A method for producing a catalyst slurry for exhaust gas denitration, comprising a step of obtaining an aqueous solution of a compound represented by o ₂ V ₃ O ₁₅ and a step of dispersing titanium oxide in the aqueous solution. 4. A catalyst for exhaust gas denitration, comprising a catalyst substrate made of metal, glass or ceramic coated with the slurry according to claim 1 or 2. 5. The denitration catalyst according to claim 4, wherein the catalyst substrate is a mesh having through holes, and the catalyst is coated so as to fill the mesh. 6. The exhaust gas denitration catalyst according to claim 4, wherein the catalyst substrate is a net-like base material having a through hole, and the catalyst is coated in a state where the mesh has a through hole. . 7. The exhaust gas according to claim 4, wherein the catalyst base is a flat plate, and the flat plate is formed with corrugations, irregularities, and step-like projections. DeNOx catalyst. 8. A denitration catalyst structure wherein the plate-shaped denitration catalyst according to claim 7 is laminated, and a gas passage is formed between said denitration catalysts. 9. The method for producing a denitration catalyst slurry according to claim 3, wherein the catalyst is coated by immersing the plate-like catalyst in the slurry according to claim 1 or 2. 10. A catalyst base having a corrugated, uneven, or stepped projection formed on a flat base material surface, which is previously laminated and integrated, and then immersed in the catalyst slurry according to claim 1 or 2. A method for producing a catalyst structure for exhaust gas denitration, comprising coating a catalyst by heating. 11. The atomic ratio of vanadium to molybdenum V /
The chemical formula (NH ₄ ) ₃ Mo, wherein Mo is substantially 3/2.
₂ An exhaust gas denitration catalyst comprising a compound represented by V ₃ O ₁₅ supported on titanium oxide particles.