JP2001113169A - Exhaust gas treating catalyst and method for treating exhaust gas - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a catalyst capable of removing such organic halogen compounds as dioxins in an exhaust gas, denitrating and decomposing ammonia and an exhaust gas treating method using the catalyst. SOLUTION: In an exhaust gas treating catalyst containing amorphous titanium oxide, the peak intensity exhibiting an anatase crystal present at 2θ=24.7 to 25.7 deg. of the X-ray powder diffraction is controlled to <=75% of the peak intensity exhibiting an anatase crystal present at 2θ=24.7 to 25.7 deg. of the X-ray powder diffraction of a reference material (titanium oxide DT-51 made by Millennium Co.) containing 5 wt.% V2O5 and 95 wt.% TiO2.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to an exhaust gas treating catalyst, a method for producing the same, and an exhaust gas treating method. In particular, a catalyst for removing organic halogen compounds such as dioxins in exhaust gas, a denitration catalyst for removing nitrogen oxides (NOx) in exhaust gas, and a catalyst for decomposing ammonia in exhaust gas. The present invention relates to an exhaust gas treatment catalyst excellent as an ammonia decomposition catalyst, a method for producing the same, and an exhaust gas treatment method.

[0002]

2. Description of the Related Art Dioxins and PCs are contained in exhaust gas generated from incineration facilities for treating industrial waste and municipal waste.
It contains very small amounts of toxic organic halogen compounds such as B and chlorophenol, and especially dioxins are extremely toxic even in a very small amount, and have serious effects on the human body. ing. In general, organic halogen compounds are extremely stable chemically, and in particular, dioxins are substances that are hardly decomposed as they are said to remain semipermanently in nature, and their content in exhaust gas is very low Therefore, it is difficult to remove this efficiently with a conventional exhaust gas treatment catalyst. Until now, noble metal catalysts such as a catalyst in which vanadium oxide or tungsten oxide is supported on titanium oxide or platinum have been used, but depending on the exhaust gas conditions, they cannot be said to have sufficient performance, and further improvement in catalyst performance is required. Is desired.

[0003] As a method of removing nitrogen oxides from exhaust gas which has been put into practical use at present, nitrogen oxides in the exhaust gas are catalytically reduced on a denitration catalyst using a solid reducing agent such as ammonia or urea, and harmless. The selective catalytic reduction (SCR) method, which decomposes into nitrogen and water, is common. As a denitration catalyst used for this, for example, a titanium-vanadium-based catalyst described in JP-A-10-235206 is known, but it cannot be said that the catalyst has sufficient performance depending on exhaust gas conditions.
Further improvement in catalyst performance is desired. In the purification of exhaust gas containing ammonia, Pt-Al ₂
Noble metal catalysts such as O ₃ catalyst, Ni, Mn, Cu, Fe
Metal oxide-based catalysts such as are generally used. However, when the ammonia decomposition activity becomes high, there remains a problem that NOx is generated in addition to nitrogen and water as a reaction product, and these solutions are desired. I have.

[0004]

SUMMARY OF THE INVENTION An object of the present invention is to provide a catalyst excellent in the performance of removing organic halogen compounds such as dioxins in exhaust gas, denitration performance, and ammonia decomposition performance, a method for producing the same, and the use of this catalyst. It is to provide an exhaust gas treatment method.

[0005]

Means for Solving the Problems The present inventors have confirmed that a catalyst containing titanium oxide is basically effective, and in general, remove organic halogen compounds, denitrate, and decompose ammonia. By using titanium oxide with a higher percentage of an amorphous structure instead of titanium oxide with a higher percentage of anatase structure, which has been considered to be highly active, trace amounts of harmful substances (organic halogen compounds,
The catalyst is designed to improve the adsorptive power to nitrogen oxides and ammonia) and the contact efficiency of the exhaust gas with the catalyst, and to promote the decomposition reaction of a trace amount of harmful substances contained in the exhaust gas.

That is, the exhaust gas treatment catalyst according to the present invention is a catalyst for removing organic halogen compounds containing titanium oxide in an amorphous phase.
The peak intensity indicating an anatase crystal present between 4.7 ° and 25.7 ° indicates that the reference substance is 5% by weight V ₂ O ₅ −
95% by weight TiO ₂ (titanium oxide DT- manufactured by Millennium)
51) The peak intensity of the anatase crystal present between 2θ = 24.7 ° and 25.7 ° in the powder X-ray diffraction of 7
It is not more than 5%. Further, the intensity of a peak indicating an anatase crystal existing between 2θ = 24.7 ° and 25.7 ° in powder X-ray diffraction measured under the following conditions is 1
It is not more than 0000 counts / sec.

Model Rigaku RE-300 X-ray source CuKα1 / 50 kV / 300 mA Counter Scintillation counter No filter Monochromator Curved crystal monochromator Divergence slit 1 ゜ Scattering slit 1 ゜ Receiving slit 0.3 mm Scanning speed 4 ゜ / min

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in detail.
The catalyst of the present invention contains a certain amount or more of titanium oxide in an amorphous phase as a component thereof.
The intensity of the peak indicating an anatase crystal existing between 2θ = 24.7 ° and 25.7 ° in the line diffraction is between 2θ = 24.7 ° and 25.7 ° in the powder X-ray diffraction of the reference substance. It is characterized by being at most 75% of the intensity of the peak indicating the existing anatase crystal, preferably at most 50%. In other words, the intensity of the peak indicating the anatase crystal existing between 2θ = 24.7 ° and 25.7 ° in the powder X-ray diffraction measured under the following conditions with respect to the above-mentioned reference substance is about 1302.
7 counts / sec, the catalyst of the present invention has 75%
Of about 10,000 counts / sec or less, preferably 6500 counts / sec or less.

Model Rigaku RE-300 X-ray source CuKα1 / 50 kV / 300 mA Counter Scintillation counter No filter Monochromator Curved crystal monochromator Divergence slit 1 ゜ Scattering slit 1 ゜ Receiving slit 0.3 mm Scanning speed 4 ゜ / min Titanium oxide anatase The crystal was 2θ = 2 in powder X-ray diffraction.
Although a peak is shown between 4.7 ° and 25.7 °, titanium oxide in the amorphous phase does not show a crystalline peak. Therefore, the smaller the peak intensity, the lower the proportion of anatase-type titanium oxide and the greater the proportion of amorphous phase titanium oxide. The reference substance used in the present invention is 5% by weight V ₂ O ₅ -95% by weight TiO ₂ (titanium oxide DT-51 manufactured by Millennium Co.), and its manufacturing method is as shown in Examples described later. Titanium oxide in the reference material has a very high anatase ratio.

[0010] The type of titanium source used in preparing the catalyst of the present invention is not particularly limited, as long as it generates titanium oxide by firing, in addition to titanium oxide. For example, an inorganic titanium compound such as titanium tetrachloride and titanium sulfate, and an organic titanium compound such as titanium oxalate and tetraisopropyl titanate can be used, and it is preferable to use a soluble titanium compound or a titanium alkoxide. The catalyst of the present invention contains at least one oxide selected from the group consisting of vanadium, molybdenum, tungsten, manganese, cobalt, nickel, zinc, zirconium, niobium, tin, tantalum, lanthanum, and cerium as constituent components. It is preferable to use vanadium oxide among them. The content of these oxides is preferably from 0.1 to 50% by weight, more preferably from 5 to 20% by weight.

When these metal oxides are contained,
There is no particular limitation on the starting material of each element. In addition to these oxides, any of hydroxides, ammonium salts, oxalates, halides, sulfates, nitrates, and the like that generate the oxide after firing can be used. The catalyst of the present invention further comprises, as constituent components, at least one metal selected from the group consisting of palladium, platinum, rhodium, ruthenium, silver, gold and iridium and / or
Or it is preferable to contain the metal oxide, and among these, platinum is particularly preferable. These metals and / or
Alternatively, the content of the metal oxide is preferably 0.01 to 5% by weight, more preferably 0.05 to 0.5% by weight.
% By weight.

To prepare the catalyst of the present invention, a titanium hydroxide is prepared by neutralizing a soluble titanium compound or hydrolyzing a titanium alkoxide.
It is preferable to obtain titanium oxide by firing at 400C, preferably 400C to 500C. If the firing temperature is lower than 350 ° C., there is a high possibility that the catalyst will undergo thermal degradation during the reaction. If the firing temperature exceeds 550 ° C., the proportion of anatase-type titanium oxide increases. Specifically, it is preferably prepared, for example, by the following procedure. (A) While stirring an aqueous solution of a soluble titanium compound such as titanium chloride, a base such as ammonia is added dropwise thereto to obtain a hydroxide precipitate of titanium. It is assumed that the precipitation is completed when the pH finally reaches 6 to 9. It is preferable to keep the temperature of the aqueous solution at 50 ° C. or less during the dropwise addition of the basic substance in order to suppress generation of crystal nuclei of titanium oxide. The precipitate is aged, washed well, and then calcined in the above temperature range. (B) While stirring the distilled water, an alkoxide of titanium is added dropwise to obtain a hydroxide precipitate of titanium. A small amount of ammonia is added to complete the precipitation. After thoroughly washing the precipitate, baking is performed in the above temperature range. Further, by adding an oxide or a salt such as silicon, yttrium, cerium, or sulfur to the titanium hydroxide precipitate of (A) or (B), followed by firing,
Alternatively, by co-precipitating oxides or salts such as silicon, yttrium, cerium, and sulfur at the time of precipitation of the titanium hydroxide of (A) and (B), followed by firing,
Anatase crystallization and rutile crystallization of titanium oxide can be suppressed, and the amorphous structure of titanium oxide can be maintained even at a firing temperature of 400 ° C. or more.

[0013] Titanium oxide (hereinafter referred to as "component A") is at least one selected from the group consisting of vanadium, molybdenum, tungsten, manganese, cobalt, nickel, zinc, zirconium, niobium, tin, tantalum, lanthanum and cerium. Oxide (hereinafter referred to as "B component")
For example, a method of adding a salt of the component B or a solution thereof to the powder or slurry of the component A, or a method of impregnating and supporting a solution of the salt of the component B on a molded body of the component A. And the like. That is, the molded body of the catalyst of the present invention may be used by molding from a powder or a slurry composed of the component A and the component B or a salt thereof, or the component B may be supported on a molded body composed of the component A. Can also be used.

The catalyst of the present invention may be used by shaping it into a plate, corrugated plate, mesh, honeycomb, column, or cylinder shape, or may be used in the form of alumina, silica, cordierite, or the like.
Plate, corrugated, made of titania, stainless metal, etc.
It may be used by being supported on a carrier having a mesh shape, a honeycomb shape, a column shape, a cylindrical shape, or the like. By using the catalyst of the present invention, not only the adsorption power for trace amounts of harmful substances in the exhaust gas and the contact efficiency of the exhaust gas with the catalyst are improved,
The active ingredient content such as vanadium oxide can be significantly increased as compared with the case where anatase-type titanium oxide or rutile-type titanium oxide is used.

The catalyst of the present invention is used for treating various exhaust gases. The composition of the exhaust gas is not particularly limited, but the catalyst of the present invention is very useful as a catalyst for removing organic halogen compounds, a denitration catalyst, and an ammonia decomposition catalyst. When the catalyst of the present invention is used as a catalyst for removing an organic halogen compound, the composition of an exhaust gas treated using the catalyst of the present invention is not particularly limited as long as it contains an organic halogen compound. Especially dioxins and PC
It is suitable for treating exhaust gas containing B. In order to remove the organic halogen compound using the catalyst of the present invention, the exhaust gas must be reduced to 13
It is desirable to contact the catalyst of the present invention at a temperature of 0 to 350 ° C, preferably 150 to 250 ° C.

When the catalyst of the present invention is used as a denitration catalyst, the catalyst of the present invention is brought into contact with exhaust gas in the presence of a reducing agent such as ammonia or urea to reduce and remove nitrogen oxides in the exhaust gas. There are no particular restrictions on the conditions at this time.
The reaction can be carried out under conditions generally used for this type of reaction. Specifically, the temperature may be appropriately determined in consideration of the type and properties of the exhaust gas, the required nitrogen oxide decomposition rate, and the like, but the temperature is preferably 130 to 550 ° C. If the temperature of the exhaust gas is lower than 130 ° C., the denitration efficiency is reduced. If the temperature exceeds 550 ° C., problems such as sintering of the active ingredient occur. When the catalyst of the present invention is used as an ammonia decomposition catalyst, the conditions are not particularly limited, and the reaction can be carried out under conditions generally used for this type of reaction. The exhaust gas treatment temperature is preferably from 130 to 550 ° C. If the temperature is lower than 130 ° C., the decomposition efficiency is low. If the temperature is higher than 550 ° C., sintering of the active ingredient and generation of NOx occur.

Under the conditions for treating exhaust gas using the catalyst of the present invention,
The type and properties of the exhaust gas and the required dioxy
Depends on the decomposition rate of organic halogen compounds such as
Therefore, they cannot be specified unconditionally.
May be appropriately determined in consideration of the above condition. Of the gas to be treated
Space velocities for the catalysts of the invention are from 100 to 10,000
0Hr^-1, Preferably 200-50,000Hr^-1In the range
Is good. 100Hr ^-1If the value is less than
It is too inefficient and becomes 100000Hr^-1A place beyond
In this case, the decomposition efficiency is reduced.

[0018]

The present invention will be described in more detail with reference to the following examples, but the present invention is not limited to these examples. The powder X-ray diffraction was measured under the following conditions. Model Rigaku RE-300 X-ray source CuKα1 / 50 kV / 300 mA Counter Scintillation counter Filter None Monochromator Curved crystal monochromator Divergence slit 1 ゜ Scattering slit 1 ゜ Receiving slit 0.3 mm Scanning speed 4ｍｉｎ / min [Preparation example (reference material Synthesis)] To 20 kg of titanium oxide (DT-51 manufactured by Millennium Co.), add a chemical solution obtained by dissolving 1.4 kg of ammonium metavanadate, 1.7 kg of oxalic acid, and 0.4 kg of monoethanolamine in 5 liters of water until uniform. Mix well. Next, after drying at 80 ° C., it was baked at 450 ° C. for 5 hours in an air atmosphere to obtain V _2.
A reference material having a composition of O ₅ : TiO ₂ weight ratio = 5: 95 was obtained.

FIG. 1 shows an X-ray powder diffraction spectrum of the obtained reference substance. The peak intensity indicating an anatase crystal existing between 2θ = 24.7 ° and 25.7 ° has an intensity of 1302.
7 counts / sec. [Example 1] Titanium oxide was prepared by the method described below. A sulfuric acid solution of titanyl sulfate (125 g / liter as TiO ₂ ,
340 liters (sulfuric acid concentration: 550 g / liter) were gradually added dropwise with stirring. After leaving the obtained gel for 3 hours,
The extract was washed with filtered water and subsequently dried at 100 ° C. for 10 hours. Then, it was fired at 400 ° C. The intensity of the X-ray diffraction peak indicating the anatase crystal was 3850 counts / sec, which was 30% of the reference substance.

Next, 1.4 kg of ammonium metavanadate, 1.7 kg of oxalic acid,
A chemical solution prepared by dissolving 0.4 kg of monoethanolamine in 5 liters of water was added, and 1 kg of phenolic resin and starch as a molding aid were added and mixed, kneaded with a kneader, and then extruded with an extruder to form an 80 mm square opening. 4.0m
m, a thickness of 1.0 mm, and a length of 500 mm. Next, after drying at 80 ° C., it was calcined at 380 ° C. for 5 hours in an air atmosphere to obtain a catalyst (A). The composition of the catalyst (A) thus obtained was as follows: V ₂ O ₅ : TiO ₂ = 5: 95
(Weight ratio). The intensity of the X-ray diffraction peak indicating the anatase crystal was 4688 counts / sec, which was 36% of the reference substance.

FIG. 2 shows an X-ray powder diffraction spectrum of the catalyst (A). [Example 2] A preparation method similar to the method described in Example 1,
A catalyst (B) having a composition of V ₂ O ₅ : TiO ₂ = 3: 97 (weight ratio) was prepared. The intensity of the X-ray diffraction peak indicating the anatase crystal was 4326 counts / sec, which was 33% of the reference substance. [Example 3] A preparation method similar to that described in Example 1 was used.
A catalyst (C) having a composition of V ₂ O ₅ : TiO ₂ = 10: 90 (weight ratio) was prepared. The intensity of the X-ray diffraction peak indicating the anatase crystal was 4796 counts / sec, which was 37% of the reference substance.

Example 4 The catalyst (A) prepared in Example 1 was impregnated with a 0.01M aqueous solution of palladium nitrate, dried at 120 ° C. and calcined at 350 ° C. to obtain a catalyst (D). . The carried amount of palladium oxide was 0.06% by weight. Comparative Example 1 The titanium oxide prepared by the method described in Example 1 was further calcined at 550 ° C. to obtain a titanium oxide having a high anatase crystallinity. The intensity of the X-ray diffraction peak indicating the anatase crystal was 10,343 counts / sec, which was 79% of that of the reference substance. 20 kg of titanium oxide having a high anatase crystallinity is added to 1.4 kg of ammonium metavanadate.
g, oxalic acid 1.7 kg, monoethanolamine 0.4
of a phenolic resin and a starch as a molding aid are mixed and kneaded with a kneader, and then extruded with an extruder.
mm square, aperture 4.0 mm, wall thickness 1.0 mm, length 50
It was formed into a 0 mm honeycomb shape. Next, after drying at 80 ° C., it was calcined at 450 ° C. for 5 hours in an air atmosphere to obtain a catalyst (A ′). The composition of the catalyst (A ′) thus obtained was V ₂ O ₅ : TiO ₂ = 5: 95 (weight ratio).
The intensity of the X-ray diffraction peak indicating the anatase crystal was 1172.
6 counts / sec, 90% of the reference material.

Comparative Example 2 A catalyst (B ') having a composition of V ₂ O ₅ : TiO ₂ = 3: 97 (weight ratio) was prepared by the same preparation method as described in Comparative Example 1. The intensity of the X-ray diffraction peak indicating the anatase crystal was 11665 counts / sec, which was 90% of that of the reference substance. Comparative Example 3 A preparation method similar to the method described in Comparative Example 1 was used.
A catalyst (C ′) having a composition of V ₂ O ₅ : TiO ₂ = 10: 90 (weight ratio) was prepared. The intensity of the X-ray diffraction peak indicating the anatase crystal was 11796 counts / sec, which was 91% of the reference substance.

Comparative Example 4 The catalyst (A ') prepared in Comparative Example 1 was impregnated with a 0.01M aqueous solution of palladium nitrate, dried at 120.degree. C. and calcined at 350.degree. Obtained. The carried amount of palladium oxide was 0.06% by weight. Example 5 Organochlorine compound decomposition tests were performed using the catalysts (A) to (D) and (A ') to (D') prepared in Examples 1 to 4 and Comparative Examples 1 to 4. Chlorophenol (hereinafter abbreviated as CP) as the organochlorine compound to be treated
The reaction was carried out under the following conditions.

The results are shown in Table 1. CP decomposition rate or C
The P removal rate was determined by the following equation. (Test conditions) Processing gas composition CP: 30 ppm, O ₂ : 10%, H ₂ O: 15%,
N ₂ : Balance Gas temperature: 160 ° C. Space velocity (SV): 4000 Hr ⁻¹ (Formula) CP decomposition rate (%) = [(CP concentration at reactor inlet) − (CP concentration at reactor outlet)] / (Reactor inlet) CP concentration) x 100

[0026]

[Table 1]

As shown in Table 1, in the catalyst of the comparative example, the removal rate of the organic halogen compound increases with the increase of the vanadium oxide content, but hardly increases at 5% or more. On the other hand, in the case of the catalyst containing a large amount of amorphous titanium oxide according to the embodiment, the removal rate of the organic halogen compound increases with the increase of the vanadium oxide content, and at 10%, the organic halogen compound is much higher than the conventional catalyst. Indicates the removal rate. Example 6 Using the catalysts (A) and (A ') prepared in Example 1 and Comparative Example 1, a denitration reaction was carried out under the following conditions. When the denitration rate was calculated by the following equation, it was 99% for the catalyst (A) and 94% for the catalyst (A ').
Met.

(Test conditions) Composition of processing gas: NO: 190 ppm, NH ₃ : 190 ppm, O ₂ : 9
%, H ₂ O: 17%,: N ₂ : Balance Gas temperature: 250 ° C. Space velocity (SV): 4000 Hr ⁻¹ (Formula) Denitration rate (%) = [(reactor inlet NOx concentration) − (reactor outlet) NOx concentration)] / (NOx concentration at reactor inlet) × 10
[Example 7] Using the catalysts (D) and (D ') prepared in Example 4 and Comparative Example 4, an ammonia decomposition reaction was carried out under the following conditions. When the ammonia decomposition rate was determined by the following equation, it was 98% for the catalyst (D) and 93% for the catalyst (D ').

(Test conditions) Composition of processing gas NH ₃ : 30 ppm, O ₂ : 2%, H ₂ O: 10%,
N ₂ : Balance Gas temperature: 330 ° C. Space velocity (SV): 4000 Hr ⁻¹ (Formula) Ammonia decomposition rate (%) = [(reactor inlet ammonia concentration) − (reactor outlet ammonia concentration)] / (reactor inlet) Ammonia concentration) x 10
0

[0030]

The catalyst of the present invention is excellent in the activity of decomposing toxic organic halogen compounds such as dioxins and the activity of decomposing ammonia. It also has excellent denitration performance and is useful as a catalyst for simultaneous removal of toxic organic halogen compounds such as nitrogen oxides and dioxins.

[Brief description of the drawings]

FIG. 1 Powder X-ray diffraction spectrum of a reference substance prepared in Preparation Example

FIG. 2 is a powder X-ray diffraction spectrum of the catalyst (A) prepared in Example 1.

Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat II (reference) B01J 23/10 B01J 23/16 A 23/14 23/38 A 23/16 23/74 A 23/38 B01D 53/36 E23 / 648 G 23/74 102B 102C B01J 23/64 102A (72) Inventor: Atsushi Morita 992, Nishioki, Okihama-shi, Aboshi-ku, Himeji-shi, Hyogo 1 Nippon Shokubai Co., Ltd. No. 992, Nishioki, Okihama, Abashiri-ku, Japan Nippon Shokubai Co., Ltd. (72) Noboru Sugishima Inventor No. 992, Nishioki, Nishioki, Abashiri-ku, Himeji-shi, Hyogo Pref. BA21Y BA23X BA24Y BA26Y BA27Y BA28Y BA30Y BA31X BA32Y BA33Y BA34Y BA37Y BA38Y BA41X BB02 4G069 AA02 AA03 AA08 AA09 AA11 AA12 BA04A BA04B BA04C BB04A BB04B BC22A BC32A BC33A BC35A BC42A BC43A BC51A BC54A BC54B BC54C BC55A BC56A BC59A BC60A BC62A BC67A BC68A BC70A BC71A BC72A BC72B BC74A BC75A CA02 CA10 CA11 CA1 3 CA19 DA06 EC22X EC25 EC26 FB08 FB13

Claims (6)

[Claims] 1. An exhaust gas treatment catalyst containing titanium oxide in an amorphous phase, wherein 2θ = 2 in powder X-ray diffraction.
The peak intensity indicating an anatase crystal present between 4.7 ° and 25.7 ° indicates that the reference substance is 5% by weight V ₂ O ₅ −
95% by weight TiO ₂ (titanium oxide DT- manufactured by Millennium)
51) The peak intensity of the anatase crystal present between 2θ = 24.7 ° and 25.7 ° in the powder X-ray diffraction of 7
An exhaust gas treatment catalyst characterized by being at most 5%. 2. An anatase crystal present between 2θ = 24.7 ° and 25.7 ° in powder X-ray diffraction measured under the following conditions in a catalyst for treating exhaust gas containing titanium oxide in an amorphous phase. An exhaust gas treatment catalyst having a peak intensity of 10,000 counts / second or less. Model Rigaku RE-300 X-ray source CuKα1 / 50kV / 300mA Counter Scintillation counter No filter Monochromator Curved crystal monochromator Divergence slit 1 ゜ Scattering slit 1 ゜ Receiving slit 0.3mm Scanning speed 4 ゜ / min 3. An amount of at least one oxide selected from the group consisting of vanadium, molybdenum, tungsten, manganese, cobalt, nickel, zinc, zirconium, niobium, tin, tantalum, lanthanum and cerium is 0.1 to 50% by weight. The exhaust gas treating catalyst according to claim 1 or 2, which is contained at a concentration of: 4. A composition containing at least one metal selected from the group consisting of palladium, platinum, rhodium, ruthenium, silver, gold and iridium and / or a metal oxide thereof in a concentration of 0.01 to 5% by weight. Claim 1
4. The exhaust gas treating catalyst according to any one of the above items 3. 5. A method comprising preparing a titanium hydroxide by neutralizing a soluble titanium compound or hydrolyzing a titanium alkoxide, and calcining the titanium hydroxide at 350 ° C. to 550 ° C. to obtain titanium oxide. The method for producing an exhaust gas treating catalyst according to any one of the above. 6. An exhaust gas treatment method comprising contacting exhaust gas with the exhaust gas treatment catalyst according to claim 1.