KR102303999B1 - Sulfated catalyst for selectively reducing nitric oxide and methode for fabrication thereof - Google Patents

Abstract

The present invention relates to a catalyst for reducing nitrogen oxide and a method for preparing the same, and a promoter including antimony oxide (Sb-oxide), copper vanadate crystal grains represented by the following [Formula 1] and a carrier on which the copper vanadate crystal grains and the promoter are supported, wherein the copper vanadate crystal grains are subjected to sulfation treatment to form copper sulfate or vanadium sulfate on at least a portion of the surface.
[Formula 1]
Cu _X V ₂ O _X+5
Here, X is an integer having a value of 3 or 5.

Description

Sulfuration-treated catalyst for reducing nitrogen oxides and manufacturing method thereof

The present invention relates to a catalyst for reducing sulfurized nitrogen oxides and a method for preparing the same. In more detail, nitrogen with improved performance by sulfiding the surface of the catalyst included in the selective catalytic reduction of nitric oxide by NH ₃ , NH _{3 -SCR using ammonia (NH 3 ) as a reducing agent} It relates to a catalyst for reducing oxide and a method for preparing the same.

Recently, interest in a process capable of efficiently converting nitrogen oxide, which is one of the main precursors of fine dust formation, contained in flue gas of ships, power plants, and diesel vehicles, is increasing. One of the effective methods for this is a process of converting nitrogen oxides into nitrogen and water vapor using ammonia as a reducing agent (selective catalytic NO _X reduction by NH ₃ , NH ₃ -SCR), which is obtained by Equations (1) and (2) is expressed as

4NO + 4NH ₃ + O ₂ → 4N ₂ + 6H ₂ O _… (One)

2NO ₂ + 4NH ₃ + O ₂ → 3N ₂ + 6H ₂ O _… (2)

In the above process, 1) development of catalyst material, 2) improvement of catalyst surface properties, 3) _{improvement of NH 3} -SCR reaction performance, 4) sulfur dioxide/ammonium (SO ₂ /ammonium), sulfate/ammonium bisulfate of catalyst material Improvement of durability against (sulfate/ammonium bisulfate, ABS), alkali-metal, and thermal aging is a problem. In the case of SO _2, NH ₃ -SCR is oxidized during the reaction is converted to SO ₃ (formula _(3)), SO 3 is H ₂ O or H ₂ O / NH ₃ and reaction with H ₂ SO ₄ or through the ABS by-products are formed (Eqs. (4) and (5)). In the case of _{H 2} SO _{4 , it causes a serious corrosion problem at the rear end of the NH 3} -SCR catalyst process, and in the case of ABS, the catalyst surface is poisoned to reduce the nitrogen oxide conversion rate of the catalyst.

SO ₂ + ½ O ₂ → SO _{3 …} (3)

SO ₃ + 2NH ₃ + H ₂ O → (NH ₄ ) ₂ SO _{4 …} (4)

SO ₃ + NH ₃ + H ₂ O → (NH ₄ )HSO _{4 …} (5)

In the case of alkali-metals such as Na or K contained in fly ash of power plants, one of the compounds that can affect the deterioration of the durability of the catalyst, NH ₃ -SCR progress It may be mixed with a feed gas for supply to the catalyst surface. These alkali metal species poison the active acid sites (Bronsted acid or Lewis acid sites) on the catalyst surface during the _{NH 3 -SCR reaction, and are a major cause of lowering the conversion rate of nitrogen oxides.} In the case of thermal aging, which is another factor that degrades the durability of the catalyst, active points on the catalyst surface and gradual agglomeration of the promoter particles are caused when the diesel vehicle is driven for a long time. This is a major cause of lowering the conversion rate of nitrogen oxides contained in the exhaust gas of automobiles, since _{NH 3} or NO _{X reduces the surface density of the accessible active sites/procatalysts.}

On the other hand, _{in the case of a catalyst containing copper vanadate (Cu 3} V ₂ O ₈ or Cu ₅ V ₂ O ₁₀ ) as an active site and an antimony oxide of the periodic table incorporated as a promoter, and a nitrogen oxide reduction reaction system using the same, similar V Compared to a commercial catalyst having a content (V ₂ O ₅ -WO ₃ / TiO ₂ ), it shows improved NH ₃ -SCR performance and _{durability against SO 2} /ABS.

_{The present invention improves the NH 3} -SCR reaction performance by further improving the surface properties of the catalyst (eg, Cu ₃ V ₂ O ₈ -Sb/TiO ₂ ), and improves the durability of the catalyst for _{SO 2 /ABS,} An object of the present invention is to improve the durability of the catalyst against alkali metal species and deterioration.

However, these problems are exemplary, and the scope of the present invention is not limited thereto.

According to one aspect of the present invention for solving the above problems, a promoter comprising antimony oxide (Sb-oxide), copper vanadate crystal particles represented by the following [Formula 1], and the There is provided a catalyst for reducing nitrogen oxides, comprising copper vanadate crystal grains and a support on which the promoter is supported, wherein the copper vanadate crystal grains are sulfided to form copper sulfate or vanadium sulfate on at least a portion of the surface.

[Formula 1]

Cu _X V ₂ O _X+5

Here, X is an integer having a value of 3 or 5.

In addition, according to an embodiment of the present invention, the catalyst may have a porous surface.

In addition, according to an embodiment of the present invention, the copper vanadate crystal grains may have a diameter of 0.1 nm to 500 μm.

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In addition, according to an embodiment of the present invention, the support _{is any one of carbon (C), Al 2} O ₃ , MgO, ZrO ₂ , CeO ₂ , TiO ₂ and SiO ₂ , compared to 100 parts by weight of the support. The promoter may include 10 ^-4 to 50 parts by weight, and the iron vanadate crystal grains may include 10 ^-4 to 50 parts by weight relative to 100 parts by weight of the carrier.

And, according to one aspect of the present invention for solving the above problems, a catalyst comprising a promoter including antimony oxide (Sb-oxide), copper vanadate crystal grains represented by the following [Formula 1], and a support A method for preparing a catalyst for nitrogen oxide reduction comprising the steps of preparing a copper vanadate crystal grain and sulfiding the copper vanadate crystal grain, wherein the nitrogen oxide reduction catalyst comprises the copper vanadate crystal grain and the promoter There is provided a method for producing a catalyst for reducing nitrogen oxides supported on a support, wherein copper sulfate or vanadium sulfate is formed on at least a portion of the surface of the copper vanadate crystal grains.

[Formula 1]

Cu _X V ₂ O _X+5

Here, X is an integer having a value of 3 or 5.

Further, according to one embodiment of the present invention, the sulfation process is SO ₂ and O is performed by the reaction gas comprising _2, the concentration of SO ₂ and O ₂ in the reaction gas is in the range of 10ppm to 10 ⁵ ppm can have

In addition, according to an embodiment of the present invention, the flow rate of ^{the reaction gas has a range of 10 -5} mL min ^-1 to 10 ⁵ mL min ^-1 , and the pressure of the reaction gas is 10 ^-5 bar to 10 ⁵ bar.

In addition, according to an embodiment of the present invention, the sulfuration treatment may be performed at a temperature range of 200° C. to 800° C. for 0.1 hours to 24 hours.

According to an embodiment of the present invention made as described above, copper vanadate-based crystal grains (Cu ₃ V ₂ O ₈ or Cu ₅ V ₂ O ₁₀ ) and antimony oxide (Sb-oxide) are included. The performance of the catalyst for reducing nitrogen oxides can be improved by preparing a catalyst in which a promoter is dispersed in a support and sulfiding the catalyst surface.

_{In addition, the present invention improves the NH 3} -SCR reaction performance by oxidizing the surface of the catalyst to improve the active acid site (eg, Bronsted acid site) and oxidation / reduction characteristics (redox feature) _{, SO 2} It is possible to improve the durability of the catalyst against /ABS, alkali metal species and deterioration.

1 is a graph showing X-ray diffraction (XRD) patterns of _{catalysts and SO Y} ^2- functionalized catalysts according to Comparative Examples and Examples of the present invention.
2 is a high resolution transmission electron microscopy (HRTEM) photograph of _{a catalyst and SO Y} ^2- functionalized catalysts according to Comparative Examples and Examples of the present invention.
3 is a photograph showing X-ray photoelectron (XP) spectra under the O 1s region of _{catalysts and SO Y} ^2- functionalized catalysts according to Comparative Examples and Examples of the present invention.
4 is a photograph showing a background-subtracted in-situ diffuse reflectance infrared Fourier transform (DRIFT) spectra under _{SO 2} /O ₂ atmosphere and 300° C.-500° C. of catalysts according to Comparative Examples and Examples of the present invention.
_{5 to 7 are graphs showing NH 3} -SCR performance analysis results of catalysts according to Comparative Examples and Examples of the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS [0010] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS [0010] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS [0023] Reference is made to the accompanying drawings, which show by way of illustration specific embodiments in which the present invention may be practiced. These embodiments are described in sufficient detail to enable those skilled in the art to practice the present invention. It should be understood that the various embodiments of the present invention are different but need not be mutually exclusive. For example, certain shapes, structures, and characteristics described herein with respect to one embodiment may be embodied in other embodiments without departing from the spirit and scope of the invention. In addition, it should be understood that the location or arrangement of individual components within each disclosed embodiment may be changed without departing from the spirit and scope of the present invention. Accordingly, the detailed description set forth below is not intended to be taken in a limiting sense, and the scope of the invention, if properly described, is limited only by the appended claims, along with all scope equivalents to those claimed. In the drawings, like reference numerals refer to the same or similar functions in various aspects, and may be exaggerated for convenience.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings in order to enable those of ordinary skill in the art to easily practice the present invention.

The present invention relates to a catalyst for reducing nitrogen oxides having a sulfated surface and a method for preparing the same. The present invention relates to improvement of nitrogen oxide reduction reaction performance and durability of a catalyst by sulfiding a catalyst containing copper vanadate crystal grains.

According to an embodiment of the present invention, the catalyst for reducing nitrogen oxide is a promoter containing antimony oxide (Sb-oxide), copper vanadate crystal particles represented by the following [Formula 1] and It includes copper vanadate crystal grains and a support on which the promoter is supported, and the copper vanadate crystal grains are subjected to sulfation treatment to form copper sulfate or vanadium sulfate on at least a portion of the surface.

[Formula 1]

Cu _X V ₂ O _X+5

Here, X is an integer having a value of 3 or 5.

The present invention is NH ₃ -SCR catalyst for copper vanadate crystal grains, for example, Cu ₃ V ₂ O ₈ or Cu ₅ V ₂ O ₁₀ of It _{relates to functionalization by SO Y} ^{2 -} (where Y is an integer of 3 or 4) by sulfiding the surface. Functionalization of the catalyst using SO _Y ^2- can implement a catalyst surface advantageous for adsorption and conversion of nitrogen oxides during the _{NH 3} -SCR reaction, and can improve the performance of the _{NH 3 -SCR reaction compared to the non-functionalized catalyst.} In addition, the functionalization of the catalyst using _{SO Y} ^{2 -} may increase the durability against alkali metal species and deterioration during _{NH 3 -SCR reaction.}

According to an embodiment of the present invention, the method for preparing a catalyst for reducing nitrogen oxide includes a promoter including antimony oxide (Sb-oxide), copper vanadate crystal particles represented by the following [Formula 1], and a support. A method for preparing a catalyst for nitrogen oxide reduction comprising the steps of preparing a catalyst comprising: sulfiding copper vanadate crystal grains, wherein the catalyst for nitrogen oxide reduction includes copper vanadate crystal grains and a promoter; The copper vanadate crystal grains may have copper sulfate or vanadium sulfate formed on at least a part of the surface thereof.

[Formula 1]

Cu _X V ₂ O _X+5

Here, X is an integer having a value of 3 or 5.

First, a catalyst including a promoter, copper vanadate crystal grains and a support is prepared.

In the present specification, the proposed catalyst for reducing nitrogen oxides may include copper vanadate crystal grains. In particular, it may include Cu-rich copper vanadate containing a large amount of copper. In the present specification, "percopper vanadates (Cu-rich copper vanadates)" means vanadates (V ₂ O ₅ ) containing a large amount of CuO maintaining stoichiometry, for example, Cu ₃ V ₂ O ₈ (Cu ₃ O ₃ -V ₂ O ₅ ), Cu ₅ V ₂ O ₁₀ (Cu ₅ O ₅ -V ₂ O ₅ ), and the like.

The catalyst for nitrogen oxide reduction may be prepared by a conventional method to form copper vanadate crystal grains. For example, hydrothermal synthesis, solvothermal synthesis, mechano-chemical method (ball-milling), non-templated or templated synthesis, moisture The impregnation method or dry impregnation method (wet or dry impregnation method), thermal decomposition method (thermal decomposition method using Cu-V based complex) may be prepared by one or more methods.

In addition, the catalyst for nitrogen oxide reduction may include a promoter including antimony oxide (Sb-oxide).

In this case, the promoter including antimony oxide (Sb-oxide) included in the catalyst for reducing nitrogen oxides _{may reduce the binding energy between the sulfur dioxide (SO 2} ) and the surface of the catalyst. Due to this, the oxidation reaction of _{sulfur dioxide (SO 2} ) that may occur during the low-temperature SCR reaction may be minimized. That is, by minimizing the amount of ammonium sulfate adsorbed on the surface of the catalyst by reacting sulfur dioxide with ammonia, it is possible to prevent a problem in that the activity of the catalyst is reduced or corrosion by sulfuric acid occurs. Therefore, the catalyst for reducing nitrogen oxides, including a promoter, _{may have resistance to sulfur or sulfur dioxide (SO 2} ) poisoning, and it is possible to additionally provide an active site, an acid site.

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In addition, the catalyst for reducing nitrogen oxides may include a carrier on which copper vanadate crystal grains and a promoter are supported.

The active site of the catalyst must have large redox properties for smooth adsorption and conversion _{of nitrogen oxides (NO X ).} This is because the SCR cycle of nitrogen oxides is accompanied by a redox reaction with _{oxygen (O 2} ) to remove -ONO groups adsorbed to active sites on the catalyst surface. In this case, when the catalyst is prepared by supporting copper vanadate crystal grains on an appropriate support, highly reactive oxygen (O ₂ ) species present in the support can be smoothly supplied to the active site. That is, it is possible to improve the redox characteristics of the catalyst. At the same time, since copper vanadate crystal grains can be prepared in a highly dispersed form on a support, catalyst efficiency can be further improved. Therefore, it is possible to prepare a catalyst for reducing nitrogen oxides including the support having the characteristics to provide the above environment.

According to an embodiment of the present invention, the support is any one of carbon (C), Al ₂ O ₃ , MgO, ZrO ₂ , CeO ₂ , TiO ₂ and SiO ₂ ^{, and the oxide is 10 - based on} 100 parts by weight of the support. ^It contains 4 to 50 parts by weight, and the copper vanadate crystal grains relative to 100 parts by weight of the carrier may include 10 ^-4 to 50 parts by weight.

Next, sulfation treatment is performed on the prepared catalyst. The sulfation treatment according to the present invention means functionalization _{of the catalyst by SO Y} ^{2- .} As used herein, "functionalization" may refer to a process of improving the performance of a catalyst by increasing the number of active points of the catalyst or improving properties such as adsorption of reactants and catalysts. For example, when the catalyst for reducing nitrogen oxides of the present invention is subjected to sulfation treatment and _{functionalized by SO y} ^2- , a catalyst surface advantageous for adsorption and conversion of nitrogen oxides can be realized, and a new active site can be formed. .

The characteristics of the SO bond inherent in _{the SO Y} ^2- species bound to the metal species on the surface _{can be controlled through the functionalization by SO Y} ^2- by oxidizing the catalyst surface. _{Specifically, when SO Y} ^2- species present on the catalyst surface have an ionic character, they bind with the metal species of the catalyst in the form of bi-dentate binding, and have a covalent bond ( covalent character), it binds to the metal species of the catalyst in the form of mono-dentate binding. _{The NH 3} -SCR reaction performance of the catalyst may be influenced by the distribution in the catalyst of the above-mentioned binding form.

At this time, according to an embodiment of the present invention, the sulfation treatment may be performed by a reactive gas containing _{SO 2} and O _{2 .} And, the reaction gas, _{the concentration of SO 2} and O _{2 has} a range of 10ppm to 10 ⁵ ppm, the flow rate (flow rate) is 10 ^-5 mL min ^-1 to 10 ⁵ mL min ^-1 , the pressure is 10 ^-5 bar to 10 ⁵ bar. In addition, the sulfuration treatment may be performed at a temperature range of 200° C. to 800° C. for 0.1 hours to 24 hours.

When the conditions for the sulfation treatment of the catalyst are less than or equal to the above-described range, the SO _Y ^2- functionalization effect of the catalyst may be insufficient. In addition, when it is greater than or equal to the above range, oxygen species (Oα) having a reactivity that increases the activity _{of the NH 3 -SCR reaction due to excessive functionalization of the surface of the support and forming chemical adsorption may be eliminated.} Therefore, the sulfation treatment of the catalyst can be performed within the range of the above-mentioned conditions.

The catalyst modified by SO _Y ^2- _{functionalization by sulfation is SO Y} ^2- -NH ₄ form additional species. SO _Y ^2- -NH ₄ The species becomes a Bronsted acid site capable of adsorbing the reducing agent ammonia (NH _{3 ).} That is, the functionalized catalyst subjected to the sulfation treatment according to the present invention can increase the number of reactive sites compared to the non-functionalized catalyst. In addition, the catalyst modified by the functionalization using _{SO Y} ^2- may increase the oxidation/reduction characteristics compared to the non-functionalized catalyst by additionally forming _{metal-SO Y} ^{2- species.} In addition, metal-SO _Y ^2- species can improve the production efficiency of _{NO 2 for the fast NH 3} -SCR reaction of Equation (6) below.

NO + NO ₂ + 2NH ₃ → 2N ₂ + 3H ₂ O … (6)

Therefore, the catalyst for nitrogen oxide reduction according to the present invention can implement a catalyst surface advantageous for adsorption and conversion of ammonia/nitrogen oxide by _{SO Y} ^{2- functionalization through sulfation treatment.} And, by oxidizing the surface of the catalyst, active acid sites (eg, Bronsted acid site) and oxidation / reduction characteristics (redox feature) are improved to improve NH ₃ -SCR reaction performance, SO ₂ /ABS, It is possible to improve the durability of the catalyst against alkali metal species and deterioration.

Hereinafter, embodiments for helping understanding of the present invention will be described. However, the following examples are provided only to help the understanding of the present invention, and the embodiments of the present invention are not limited to only the following examples.

Example

1 to 7, catalyst synthesis according to Examples and Comparative Examples of the present invention, and nitrogen oxide reduction performance evaluation according to the sulfuration treatment of the catalyst will be described.

Comparative Example 1: Cu containing Sb promoter ₃ V ₂ O ₈ -Sb/TiO ₂ Preparation of catalyst (pristine)

_{49.5 g of TiO 2} was added to 500 mL of distilled water (containing 0.5 g of Sb) in which 1.23 g of Sb(CH ₃ COO) ₃ was dissolved, stirred and dehydrated, and then calcined at 500° C. for 5 hours processing, to prepare a TiO ₂ carrier with a 3wt.% compared to TiO ₂ Sb is incorporated. Using the TiO ₂ carrier prepared above, copper vanadate (Cu ₃ V ₂ O ₈ ) crystal grains are prepared by a wet impregnation method. Specifically, an aqueous solution is prepared by dissolving 4.5 mmol of Cu(NO ₃ ) ₂ ·3H ₂ O in 240 mL of distilled water. Then, 3.0 mmol of NH ₄ VO ₃ is added, and 6 g of TiO ₂ is added to the aqueous solution and stirred. Thereafter, the solid obtained by evaporating distilled water was calcined at 500° C. for 5 hours _{to prepare a Cu 3} V ₂ O ₈ -Sb/TiO ₂ catalyst, which is referred to as Comparative Example 1.

Example 1: SO at 300°C _Y ^2- Cu functionalized with (Y=3 or 4) ₃ V ₂ O ₈ -Sb/TiO ₂ Preparation of catalyst (S300)

_{The Cu 3} V ₂ O ₈ -Sb/TiO ₂ catalyst prepared by Comparative Example 1 was diluted with N ₂ at 500 ppm of SO _{2 /3} vol.% O ₂ atmosphere and 500 mL min ^-1 300 under a flow rate of After exposure at ℃ 45 minutes and then cooled to room temperature under _{N 2 atmosphere. The catalyst (S300) prepared through SO y} ^2- functionalization by sulfation under the above conditions is hereinafter referred to as Example 1.

Example 2: SO at 400°C _Y ^2- Cu functionalized with (Y=3 or 4) ₃ V ₂ O ₈ -Sb/TiO ₂ Preparation of catalyst (S400)

Except for changing the temperature condition applied in Example 1 to 400 ℃, Cu ₃ V ₂ O ₈ -Sb/TiO _{2 Functionalization using SO Y} ^2- on the catalyst surface under the same conditions as in Example 1 was performed. The catalyst (S400) prepared through this is hereinafter referred to as Example 2.

Example 3: SO at 500°C _Y ^2- Cu functionalized with (Y=3 or 4) ₃ V ₂ O ₈ -Sb/TiO ₂ Preparation of catalyst (S500)

Except for changing the temperature condition applied in Example 1 to 500 ℃, Cu ₃ V ₂ O ₈ -Sb/TiO ₂ Functionalization using _{SO Y} ^2- on the catalyst surface under the same conditions as in Example 1. The catalyst (S500) prepared through this is hereinafter referred to as Example 3.

Comparative Example 2: Cu mixed with Na species ₃ V ₂ O ₈ -Sb/TiO ₂ Preparation of catalyst (pristine-Na)

_{The Cu 3} V ₂ O ₈ -Sb/TiO ₂ catalyst prepared by Comparative Example 1 contains 30 mol.% of Na species relative to the total number of moles of Cu, V, and Sb contained in the catalyst surface to prepare pristine-Na . Specifically, 1.5 g of Cu ₃ V ₂ O ₈ -Sb/TiO ₂ catalyst and 0.0509 g of NaNO ₃ were physically mixed with a solid obtained by calcination at 400° C. for 5 hours to pristine-Na A catalyst was prepared and referred to as Comparative Example 2.

Example 4: Preparation of S400 catalyst (S400-Na) incorporating Na species

An S400-Na catalyst was prepared in the same manner as in Comparative Example 2 except for using S400 prepared in Example 2, which is referred to as Example 4.

Comparative Example 3: Aging Cu ₃ V ₂ O ₈ -Sb/TiO ₂ Preparation of catalyst (pristine-thermal aging)

_{The Cu 3} V ₂ O ₈ -Sb/TiO ₂ catalyst prepared in Comparative Example 1 was diluted with N _{2 3vol.} % O ₂ /6vol. % of water vapor atmosphere and 500mL min ^-1 exposed at 550 °C for 200 hours under a gas flow rate and then _{cooled to room temperature under N 2} atmosphere to prepare a pristine-thermal aging catalyst, which is referred to as Comparative Example 3.

Example 5: Preparation of aging-treated S400 catalyst (S400-thermal aging)

Except for using S400 prepared according to Example 2, an S400-thermal aging catalyst was prepared in the same manner as in Comparative Example 3, which is referred to as Example 5.

The catalysts for reducing nitrogen oxides of Comparative Example 1 and Examples 1 to 3 were analyzed using an X-ray diffractomer (XRD), and the resultant X-ray diffraction pattern (XRD pattern) are shown in FIG. 1 . 1 is a graph showing X-ray diffraction (XRD) patterns of catalysts according to Comparative Examples and Examples of the present invention. 1, includes a crystal plane of all of the catalyst are anatase phase (phase anatase (TiO ₂₎₎ having a tetragonal (tetragonal) crystal structure, which means a TiO ₂ carrier. Referring to (a) of FIG. 1 , it can be seen that in the catalyst of Comparative Example 1, crystal planes representing the crystal structure of _{monoclinic Cu 3} V ₂ O _{8 were observed.}

However, referring to Figure 1 (b), in the case of Examples 1 to 3, _{crystal planes representing the crystal structure of the monoclinic Cu 3} V ₂ O ₈ are not observed, which is due to the sulfuration treatment, SO _Y ^2- This is because Cu ₃ V ₂ O ₈ decomposed and combined with Cu or V to generate new species. This can be confirmed by the _{orthorhombic CuSO 4} crystal planes observed in Examples 2 and 3.

The surface morphology of the catalysts was analyzed using high resolution transmission electron microscopy (HRTEM), and the results are shown in FIG. 2 . FIG. 2 is a high resolution transmission electron microscopy (HRTEM) photograph of catalysts according to Comparative Examples and Examples of the present invention. The catalysts of FIG. 2 have a porous structure including particles of species produced by the bonding of _{Cu 3} V ₂ O ₈ , Cu or V and SO _Y ² to anatase agglomerate having a size of several hundred nanometers. Could know. According to the N ₂ physisorption experiment, the pore properties of the catalysts have a BET surface area of 30 m ² g ^-1 to 55 m ² g ^-1 , and a BJH pore volume of 0.18 cm ³ g ^{− It} has a value in the range of 1 to 0.23 cm ³ g ^{−1 .}

Experimental Example 1: Characterization of the catalyst surface

_{NH 3} -TPD (temperature-programmed desorption), CO-pulsed chemisorption, and H ₂ -TPR (temperature-programmed reduction) experiments were performed using Comparative Example 1 and Examples 1 to 3, and the results were shown in [ Table 1] summarized.

division Comparative Example 1 Example 1 Example 2 Example 3 mmol _NH3 g ^-1 (via NH ₃ -TPD) 3.1 7.5 7.0 3.8 μmol _CO g ^-1 (via CO-pulsed chemisorption) 20.5 3.1 2.4 2.6 mmol _H2 g ^-1 (via H ₂ -TPR) 3.0 3.8 4.3 4.0

According to the results of the CO-pulsed chemisorption experiment shown in Table 1, the sulfuration-treated catalysts of Examples 1 to 3 (S300 to S500) were very small compared to the non-functionalized catalyst (pristine) of Comparative Example 1. It can be seen that includes a Lewis acid site of. This is a result of coordinatingly unsaturated, open active sites being _{occupied by SO Y} ^{2- species during the sulfation treatment of the catalyst.} _{However, according to the NH 3} -TPD (temperature-programmed desorption) test results shown in [Table 1], the catalysts of Examples 1 to 3, which were subjected to sulfuration treatment, had higher amounts of the catalysts than the non-functionalized catalysts of Comparative Example 1. It can be seen that it contains acid sites. This is SO _Y ^2- functionalized catalyst _{through sulfation treatment SO Y} ^2- -NH ₄ This is because the number of Bronsted acid sites such as et al. has increased.

In addition, it can be seen that the catalysts of Examples 1 and 2 contained a greater amount of acidic points than those of Example 3. This means that _{Examples 1 and 2, which can adsorb more ammonia during the NH 3} -SCR reaction, have superior reaction performance compared to Comparative Examples 1 and 3. _{On the other hand, in the case of H 2} -TPR (temperature-programmed reduction), which can know the oxidation/reduction characteristics of the catalyst, it can be seen that Example 2 has the greatest oxidation/reduction characteristics.

_{The relative abundance of oxygen species (O 2} species) present on the surface of the catalysts was analyzed using X-ray photoelectron (XP) spectroscopy, and the results are shown in FIG. 3 . 3 is an XP spectra photograph in the O 1s region of catalysts according to Comparative Examples and Examples of the present invention. Referring to FIG. 3 , all catalysts are O ₂ ^2- _{or oxygen species of H 2} O adsorbed on the catalyst surface (Oα′), oxygen species having reactivity and chemical adsorption (Oα), and lattice oxygen It can be seen that it contains a species (Oβ). Among the oxygen species, it was found that Example 2 had the highest relative content of Oα related to the oxidation/reduction characteristics of the catalyst [~ 47 mol. % (Example 2), <35 mol. % (Comparative Example 1, Examples 1 and 3)]. Therefore, Comparative Example 1, Example 2, which shows the best surface properties among Examples 1 to 3, has the best performance in the _{NH 3 -SCR reaction.}

_{In order to analyze the properties of SO bonding inherent in SO Y} ^2- species combined with metal species present on the surface of Examples 1 to 3, in-situ diffuse reflectance infrared Fourier transform (DRIFT) spectroscopy was used, and as a result, is shown in FIG. 4 . For this experiment, Comparative Example 1 _{was pretreated at 400 °C for 1 hour under N 2} atmosphere, and then reference spectra at 300 °C, 400 °C, and 500 °C were obtained. After that, Comparative Example 1 of 1000ppm SO ₂ /3vol. % O _{2 In an} atmosphere of 300 ℃, 400 ℃, and 500 ℃ exposed for 30 minutes, the spectrum obtained at this time is shown after subtracting the reference spectrum at each temperature. 4 is a photograph showing a DRIFT spectrum under _{SO 2} /O ₂ atmosphere and temperature of catalysts according to Comparative Examples and Examples of the present invention.

In the case of Example 1, it was found to have a peak of SO bonding with covalent bonding properties in the region of ^{1280 to 1450 cm -1} _{, which indicates that SO Y} ^2- bonded to the metal species of the catalyst has a monodentate bonding form. it means. In the case of Example 3, it was found to have a peak of SO bonding having ionic bonding characteristics in the region of ^{1250 cm -1} _{or less, which means that SO Y} ^2- bonded to the metal species of the catalyst has a bidentate bonding form. do.

However, in the case of Example 2, it was found that SO _Y ^2- bound to the metal species of the catalyst has both a monodentate bond form and a bidentate bond form. Therefore, in the case of Example 2 in which various metal-SO _Y ² -species are embedded, it is expected that only one metal-SO _Y ² -species will show _{improved NH 3} -SCR reaction performance compared to Examples 1 and 3 can

Hereinafter, Experimental Example 2 proving the analysis of Experimental Example 1 will be described with reference to FIGS. 5 to 7 . _{5 to 7 are graphs showing NH 3} -SCR performance analysis results of various catalysts according to Comparative Examples and Examples of the present invention.

Experimental Example 2: Nitrogen oxide reduction (NH ₃ -SCR) system performance analysis (1)

The performance of the SCR process was measured using the catalysts of Example 1 and Comparative Examples 1 to 3. In the temperature range of 150 ℃ to 400 ℃, sulfur dioxide (SO ₂ ) was measured without injection, the conversion rate of nitrogen oxide [NO _x conversion, shown in Fig. 5 (a)] and nitrogen _{selectivity [N 2} selectivity, Fig. 5 (b)] is shown in FIG. At this time, _{the conditions of the NH 3} -SCR process, the reaction fluid is 800ppm NO _x , 800ppm NH ₃ , 3vol. % O ₂ , 6 vol. % H _{2 O and N 2} as an inert gas, a total flow rate is 500 mL min ⁻¹ , and a space velocity of 60,000 ^{hr −1} .

Referring to FIG. 5 , it can be seen that the catalyst of Example 2 has superior performance compared to other catalysts. This is the same result as described in the surface characteristic analysis of Experimental Example 1. This is because the catalyst of Example 2 provides a greater amount of acidic active sites and provides improved redox properties compared to Comparative Examples 1, 1, and 3, respectively.

Experimental Example 3: Performance analysis of nitrogen oxide reduction (SCR) system (2)

The performance of the SCR process was measured using the catalysts of Comparative Example 2 and Example 4. In the temperature range of 150 ℃ to 400 ℃, sulfur dioxide (SO ₂ ) was measured without injection, the conversion rate of nitrogen oxide [NO _x conversion, shown in FIG. 6 (a)] and nitrogen _{selectivity [N 2} selectivity, FIG. 6 (b)] is shown in FIG. At this time, the conditions of the SCR process, the reaction fluid is 800ppm NO _x , 800ppm NH ₃ , 3vol. % O ₂ , 6 vol. % H _{2 O and N 2} as an inert gas, the total flow rate is 500 mL min ⁻¹ , and the space velocity is 60,000 ^{hr −1} .

Referring to FIG. 6 , the catalysts of Example 4 (S400-Na) and Comparative Example 2 (pristine-Na) in which the catalyst surface was intentionally poisoned using Na, an alkali metal species, were prepared in Example 2 (S400) and Compared to the catalyst of Comparative Example 1 (pristine), it can be seen that the _{NH 3 -SCR performance is inferior.} However, it can be seen that the catalyst of Example 4 showed better performance than the catalyst of Comparative Example 2. This means that Example 4, which is a sulfated catalyst, has improved resistance to alkali metals during _{NH 3} -SCR, compared to Comparative Example 2, which is a non-functionalized catalyst.

Experimental Example 4: Performance analysis of nitrogen oxide reduction (SCR) system (3)

The performance of the SCR process was measured using the catalysts of Comparative Examples 3 and 5. In the temperature range of 150 ℃ to 400 ℃, sulfur dioxide (SO ₂ ) was measured without injecting, the conversion rate of nitrogen oxide [NO _x conversion, shown in Fig. 7 (a)] and nitrogen _{selectivity [N 2} selectivity, Fig. 7(b)] is shown in FIG. At this time, the conditions of the SCR process, the reaction fluid is 800ppm NO _x , 800ppm NH ₃ , 3vol. % O ₂ , 6 vol. % H _{2 O and N 2} as an inert gas, the total flow rate is 500 mL min ⁻¹ , and the space velocity is 60,000 ^{hr −1} .

Referring to Figure 7, the catalysts of Example 5 (S400-thermral aging) and Comparative Example 3 (pristine-thermal aging) that were degraded compared to the catalysts of Example 2 (S400) and Comparative Example 1 (pristine) Inferior NH ₃ It can be seen that -SCR performance is shown. However, it can be seen that the catalyst of Example 5 showed better performance than the catalyst of Comparative Example 3. This means that the sulfated catalyst Example 5 has improved resistance to degradation during _{NH 3} -SCR, compared to Comparative Example 3, which is a non-functionalized catalyst.

Although the present invention has been illustrated and described with reference to preferred embodiments as described above, it is not limited to the above-described embodiments and is not limited to the above-described embodiments, and various methods can be obtained by those of ordinary skill in the art to which the present invention pertains within the scope of the present invention. Transformation and change are possible. Such modifications and variations are intended to fall within the scope of the present invention and the appended claims.

Claims (9)

a promoter including antimony oxide (Sb-oxide);
Copper vanadate crystal grains represented by the following [Formula 1]; and
a carrier on which the copper vanadate crystal grains and the promoter are supported;
including,
The copper vanadate crystal grains are sulphated to form copper sulfate or vanadium sulfate on at least a portion of the surface,
The SO bond contained in the copper sulfate or vanadium sulfate is provided to have a covalent character, or to have both the covalent bond and the ionic character.
Catalyst for nitrogen oxide reduction.
[Formula 1]
Cu _X V ₂ O _X+5
Here, X is an integer having a value of 3 or 5. The method of claim 1,
A catalyst for reducing nitrogen oxides having a porous surface. The method of claim 1,
The copper vanadate crystal grains have a diameter of 0.1 nm to 500 μm, a catalyst for nitrogen oxide reduction. delete The method of claim 1,
The carrier is any one of carbon (C), Al ₂ O ₃ , MgO, ZrO ₂ , CeO ₂ , TiO ₂ and SiO ₂ ,
^{The promoter contains 10 -4} to 50 parts by weight relative to 100 parts by weight of the carrier,
The copper vanadate crystal grains are 10 ^-4 to 50 parts by weight based on 100 parts by weight of the support, a catalyst for reducing nitrogen oxides. Preparing a catalyst including a promoter containing antimony oxide (Sb-oxide), copper vanadate crystal grains represented by the following [Formula 1], and a support; and
A method for preparing a catalyst for reducing nitrogen oxides, comprising the step of sulfiding the copper vanadate crystal grains,
The catalyst for reducing nitrogen oxides,
The copper vanadate crystal grains and the promoter are supported on the carrier, and the copper vanadate crystal grains have copper sulfate or vanadium sulfate formed on at least a portion of a surface thereof,
The sulfuration treatment is carried out at a temperature range of 200 ° C to 400 ° C for 0.1 hours to 24 hours,
The SO bond contained in the copper sulfate or vanadium sulfate is provided to have a covalent character, or to have both the covalent bond and the ionic character.
A method for producing a catalyst for reducing nitrogen oxides.
[Formula 1]
Cu _X V ₂ O _X+5
Here, X is an integer having a value of 3 or 5. 7. The method of claim 6,
The sulfuration treatment is performed by a reactive gas containing _{SO 2} and O _{2 ,
The concentration of SO 2} and O ₂ in the reactive gas is in the range of 10 ppm to 10 ⁵ ppm, respectively, a method for producing a catalyst for reducing nitrogen oxides. 8. The method of claim 7,
The flow rate of the reaction gas is in ^{the range of 10 -5} mL min ^-1 to 10 ⁵ mL min ^-1 , and the pressure of the reaction gas is in the range of 10 ^-5 bar to 10 ⁵ bar, nitrogen oxides A method for producing a catalyst for reduction. delete

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