KR101367023B1 - MANGANESE/TITANIA-BASED CATALYST, METHOD OF PREPARING THE SAME AND METHOD OF REMOVING NOx BY USING THE SAME - Google Patents

Abstract

The present invention relates to the preparation and application of a manganese / titania catalyst for nitrogen oxide removal, the method for preparing a manganese / titania catalyst by sequentially supporting, drying and firing a manganese precursor and a titania carrier, wherein the titania before the supporting process By measuring the surface charge of the carrier, a titania carrier having a zeta potential of 0 to 1.5 was selected, and a cerium oxide was mixed with the selected titania carrier to be supported, dried, and calcined with the manganese precursor. / Titania catalyst and manganese / titania-ceria catalyst can be provided.

Description

Manganese / Titania catalyst for removing nitrogen oxides, a method of manufacturing the same, and a method for removing nitrogen oxides using the same {MANGANESE / TITANIA-BASED CATALYST, METHOD OF PREPARING THE SAME AND METHOD OF REMOVING NOx BY USING THE SAME}

The present invention relates to the preparation and application of a manganese / titania catalyst for nitrogen oxide removal, in particular, a manganese / titania catalyst showing excellent denitrification activity in a low temperature region of 140 ~ 250 ℃ and a method for producing the same and to remove the nitrogen oxide using the same It is about how to.

Recently, it is selective with regard to the removal of nitrogen oxides (NOx: NO, NO ₂ , N ₂ O, etc.) that occur during the operation of industrial boilers, gas turbines, thermal power plants, waste incineration plants, marine engines, etc. and cause environmental pollution. Selective Catalytic Reduction (hereinafter referred to as “SCR”) is widely used.

As catalysts used for such SCRs, various catalysts have been proposed, ranging from precious metal catalysts to basic metal catalysts. However, the role of the active substance and the interaction with the carrier are known to have a significant effect on the removal characteristics of nitrogen oxides. .

Specifically, vanadium / titania catalysts, which are widely used in SCR, have recently been reported to exhibit excellent activity in the temperature range around 350 ° C. However, most of the commercially available vanadium / titania catalysts exhibit high activity in the high temperature region of 300 ° C. or higher, but have difficulty in implementing an oxidation / reduction reaction due to low activation energy in the low temperature region of about 260 ° C. or lower.

Meanwhile, "Journal of catalysis, 221, pp. 421-431, 2004" (hereinafter referred to as "prior art 1") discloses a manganese / titania catalyst as a catalyst usable in a low temperature region. Particularly, in the prior art 1, poisoning of sulfur dioxide occurs strongly during the catalytic reaction, so that the technical content of using SCR after removing sulfur dioxide before removing nitrogen oxide is introduced, and transition metals Mn, V, Co, Cu, Cr, Fe A comparison of the catalytic reaction characteristics is also shown by supporting active metals such as Ni and Ni in titania.

In addition, Korean Patent Laid-Open Publication No. 10-2010-0001315 (hereinafter referred to as "Prior Art 2") discloses a method for preparing a catalyst composition for removing nitrogen oxide and a method for removing nitrogen oxide in an exhaust gas containing water using the same. More specifically, it includes the technical content of impregnating activated carbon with a copper nitrate solution and then carrying a manganese oxide to remove nitrogen oxides.

As described above, the present study on the catalyst for removing nitrogen oxides has improved the adsorption point by improving the oxidation / reduction capacity at the low temperature (in the case of the prior art 1) or by improving the dispersion of manganese which is the active metal (the prior art 2 The main technical content is the case. However, the method of selecting a titania support for the preparation of a highly active manganese / titania catalyst, or improving the oxidation / reduction capacity at low temperature and improving the dispersion of manganese to enhance the adsorption point to increase the removal activity of nitrogen oxides Research is still insufficient, and considering such a situation, it may be said that research and development on ways to improve the activity of the catalysts are required.

The present invention has been made to solve the above-mentioned problems of the prior art, and an object of the present invention is to provide a method for selecting an optimal titania carrier among various commercial titania carriers used in the catalyst for removing nitrogen oxides.

In addition, another object of the present invention is to improve the dispersion of manganese to provide a catalyst for removing nitrogen oxides exhibiting excellent denitrification activity in a low temperature region of 140 ~ 250 ℃, a method for producing the same and a method for removing nitrogen oxides using the same There is.

As means for solving the above-mentioned technical problem,

The present invention provides a method for preparing a manganese / titania catalyst by sequentially supporting, drying and firing a manganese precursor and a titania carrier, wherein the surface charge of the titania carrier is measured before the supporting process to have a zeta potential of 0 to 1.5. It provides a method for producing a nitrogen oxide removal manganese / titania catalyst, characterized in that the titania carrier is selected, and cerium oxide is mixed with the selected titania carrier.

In this case, the cerium oxide is preferably mixed 4 ~ 8wt% based on the titania carrier, the manganese precursor is preferably mixed in 20wt% to the titania-ceria carrier.

In this case, the manganese precursor may be selected from manganese nitrate hydrate (Mn (NO ₃ ) ₂ x H ₂ O) or manganese acetate tetra hydrate ((C ₂ H ₃ O ₂ ) ₂ Mn ₄ H ₂ O). It is not particularly limited.

On the other hand, the firing process is preferably maintained for 0.5 to 5 hours at a temperature of 300 ~ 500 ℃ in a furnace of a gas atmosphere containing nitrogen, oxygen.

In this case, the furnace may be any one selected from a tube furnace, a convection furnace, or a grate furnace.

In addition, the present invention further comprises a manganese / titania-ceria catalyst comprising a titania carrier having a zeta potential of 0 to 1.5, a manganese / titania catalyst comprising a manganese precursor dispersed in the titania carrier, and a cerium oxide supported on the titania carrier. To provide.

In this case, the manganese oxide value of the manganese / titania catalyst is present in 4+ form, and the ratio of manganese atoms and titania-ceria atoms exposed on the surface is preferably 0.32 or more.

In addition, the present invention provides a method for removing nitrogen oxides by passing air containing ammonia and nitrogen oxides or exhaust gas containing moisture and nitrogen oxides through the manganese / titania-ceria catalyst for nitrogen oxide removal described above.

In this case, the oxygen concentration of the exhaust gas is 3 ~ 15%, the molar ratio of the ammonia and the nitrogen oxide may be 0.8 ~ 1.2.

On the other hand, the above-mentioned removal of the nitrogen oxide is preferably made at a temperature of 140 ~ 250 ℃ and space velocity of 60,000hr ^-1 or less.

According to the present invention, the surface charge of titania before loading of manganese is measured to select titania having a zeta potential (0 to 1.5) showing repulsion and attraction between the titania particles and the manganese particles as a carrier, and thus, a relatively large titania particle is used. Manganese particles may be uniformly dispersed in the.

In addition, by mixing 4-8 wt% of cerium oxide on a titania carrier to support manganese, the reduction ability of the catalyst and the degree of dispersion of manganese can be improved to effectively remove nitrogen oxides even in a low temperature region of 140 to 250 ° C.

1 is a graph showing the correlation between the specific surface area of titania carriers and the denitrification efficiency of manganese / titania catalysts,
2 is a graph showing the correlation between the pore size of titania carriers and the denitrification efficiency of manganese / titania catalysts,
3 is a graph showing the correlation between the total pore volume of titania carriers and the denitrification efficiency of manganese / titania catalysts,
4 is a graph showing the correlation between the surface charge of titania carriers and the denitrification efficiency of manganese / titania catalysts;
5 is a graph showing the manganese oxidation state of the manganese / titania-ceria catalyst according to the content of cerium oxide mixed in the titania carrier;
6 is an image showing the manganese dispersion state of the manganese / titania-ceria catalyst according to the content of cerium oxide mixed in the titania carrier;
7 is a graph showing ammonia adsorption characteristics of manganese / titania-ceria catalysts according to the content of cerium oxide mixed in a titania carrier;
8 is a graph showing the reducing power of the manganese / titania-ceria catalyst according to the content of cerium oxide mixed in the titania carrier.

Hereinafter, the present invention will be described in detail so that those skilled in the art can easily carry out the present invention.

In the method for preparing a manganese / titania catalyst for removing nitrogen oxides according to the present invention, a manganese precursor and a titania carrier are supported, dried and calcined, but titania having a specific range of surface charge is selected as a carrier to remove nitrogen oxides of the manganese / titania catalyst. There are technical features in improving the activity.

That is, the present invention measures the zeta potential of various commercial titania solutions before carrying manganese and selects titania having a zeta potential in the range of 0 to 1.5 as a carrier so that the attraction and repulsive force of titania particles and manganese particles are changed according to the surface charge of titania. It provides an environment to appear so that fine manganese particles can be uniformly supported on a relatively large titania surface without aggregation.

Meanwhile, in the present invention, in order to further improve the nitrogen oxide removal activity, after carrying out the mixing of 4-8 wt% of cerium oxide (CeO ₂ ) based on the titania carrier with the titania carrier selected as described above, it is another technical aspect. It features. In this case, the manganese oxide appears in the form of MnO ₂ , and the reducing power of the catalyst can be further enhanced due to the added cerium oxide.

In addition, the present invention can obtain the nitrogen oxide removal characteristics using ammonia by improving the dispersibility of manganese to enhance the adsorption power of ammonia to be described in more detail for the preparation method of manganese / titania-ceria catalyst according to the present invention do.

First, a carrier is prepared by supporting cerium oxide on titania in an amount of 4 to 8 wt% based on the weight of titania. In this case, the mixing of titania and cerium oxide is performed through the following process. Specifically, first, a rotary vacuum evaporator is used to remove the water of the titania and the cerium oxide slurry (Slurry). In this case, it is preferable to dry enough in a drying facility for at least one day so that residual water can be completely removed. When the drying is completed as described above, the titania-ceria carrier is completed by baking the sample at a temperature of 300 to 500 ° C. for 0.5 to 5 hours in a furnace in an air atmosphere.

Thereafter, an aqueous solution in which manganese precursor is dissolved, and an aqueous solution in which titania and cerium oxide are mixed are sufficiently mixed to prepare a slurry. In this case, the manganese precursor is dissolved in an aqueous solution by 20% by weight of the titania-ceria carrier. In the present invention, the manganese precursor is not particularly limited, but manganese nitrate hydrate (Mn (NO ₃ ) ₂ x H ₂ O) or manganese acetate tetra hydrate ((C ₂ H ₃ O ₂ ) ₂ Mn ₄ H ₂ O) It is preferable to use.

Subsequently, a rotary vacuum evaporator is used to remove the water from the slurry, and in this case, it is preferable to dry it at least one day in a drying facility so as to completely remove the remaining water.

Finally, the sample is fired when drying is complete. Firing is carried out for 0.5 to 5 hours at a temperature of 300 to 500 ° C. in a furnace in an air atmosphere in the same manner as the firing process of the titania-ceria carrier described above.

In the above, the method for preparing a manganese / titania catalyst for removing nitrogen oxide according to the present invention has been described. The manganese / titania-seria catalyst for nitrogen oxide removal according to the present invention prepared by the above-described method may be used by coating on structures such as metal plates, metal fibers, ceramic filters, honeycombs, or air purifiers, interior decorations, interior and exterior materials, wallpaper, etc. Can be used by coating.

In addition, the manganese / titania-ceria catalyst for nitrogen oxide removal according to the present invention may be used by extrusion processing in a particulate or monolith form with a small amount of binder. In this case, it is preferable that the catalyst is uniformly pulverized to a particle size of 1 ~ 10㎛ coated or extruded. This is because when the size of the particles is less than 1 μm, it is not preferable in terms of economics due to the fine grinding step, and when the size of the particles exceeds 10 μm, there is a problem that the uniformity and adhesion of the coating or the extrudate are lowered. In the present invention, the form of the catalyst is not particularly limited, and various forms such as honeycomb, slate, plate, pellet, and the like may be possible.

On the other hand, the manganese / titania-ceria catalyst for nitrogen oxide removal prepared according to the present invention can effectively decompose nitrogen oxides in the molar ratio of ammonia and nitrogen oxides 0.8 to 1.2, the space velocity of 60,000hr ^-1 . Here, the space velocity is an index indicating the amount of polluting gas that the catalyst can treat, which is expressed as a ratio of the amount of catalyst (volume) to the flow rate (volume) of the entire gas. It means plenty.

Removal of nitrogen oxides as described above can be made under the reaction conditions described below.

Specifically, the reactor is manufactured using a quartz tube having an inner diameter of 10 mm and a length of 600 mm, and fills quartz wool under the catalyst layer to fix the catalyst layer in the reactor. In this case, the gas injection pipe is made of stainless steel pipe, and the gas supplied to the reactor uses a MFC (Mass Flow Controller, MKS Co.) from each cylinder into which NO, N ₂ , O ₂ , and NH ₃ are injected. Adjust. On the other hand, the water supply is made by injecting N ₂ containing water into the reactor through a bubbler (bubbler), in this case circulator outside the double jacket type bubbler in order to maintain a constant supply amount The water is circulated at a constant temperature by using), and the portion flowing into the reactor is kept at 180 ° C by winding a heating band to prevent condensation of moisture. On the other hand, the temperature of the reactor is controlled by a PID temperature controller using a K-type thermocouple mounted on the fixed bed.

In the above, the preparation method and application of the manganese / titania catalyst for nitrogen oxide removal according to the present invention have been described. Hereinafter, embodiments of the present invention will be described after looking at the performance evaluation method of the present invention in detail.

First, in the manganese / titania catalyst prepared according to the present invention, the physicochemical properties of titania before manganese is loaded have a great influence on the removal efficiency of nitrogen oxide, and the physicochemical properties of titania have specific surface area, pore size and pore volume. BET (Brunauer Emmett-Teller) formula and BJH (Barrett-Joyer-Hanlenda) can be measured by. In addition, the zeta potential of the titania solution can be measured by using a zeta potential meter to measure the zeta potential of colloidal particles and solid surfaces in a dispersed state on the principle of electrophoretic light scattering (Laser Doppler method). In this case, the zeta potential is a control index of dispersion, aggregation, stability and particle functionality of the dispersion system.

Meanwhile, in the manganese / titania-ceria catalyst prepared according to the present invention, as described above, the oxidation state of manganese supported by the mixing of titania and a small amount of cerium oxide changes, and the oxidation state of manganese and titania or the characteristics of the catalyst are changed. Is analyzed and determined by XPS (X-ray Photoelectron Spectroscopy). That is, according to the XPS analysis, the characteristic peak of each element present on the surface of the catalyst is separated based on the intrinsic binding energy of the oxide containing the element, and the type of oxide present on the surface of the catalyst and Since the distribution ratio is known, XPS can indirectly confirm the effect of manganese oxide oxidation and dispersion on the selective NOx removal by analyzing the change in the oxidation of manganese oxide and the atomic distribution exposed on the catalyst surface.

In addition, the degree of dispersion can be seen the degree of dispersion on the surface through EDS Mapping, and the ammonia adsorption intensity can also be analyzed through the ammonia TPD analysis. The ammonia TPD technique can be used to evaluate the amount of adsorbed ammonia by measuring the ammonia intensity desorbed using mass spectrum while increasing the temperature of the adsorbed ammonia at room temperature after pretreatment of the catalyst for 1 hour and then increasing the temperature to 600 ° C. Can be.

On the other hand, the reduction capacity of the catalyst can be analyzed using the H ₂ -TPR technique. After pretreatment of the catalyst, after sufficiently adsorbing H ₂ at room temperature for about 1 hour, when the intensity of the desorbed H ₂ becomes constant, the reduction characteristics of the catalyst may be evaluated by measuring the H ₂ intensity using a TCD signal while increasing the temperature to 600 ° C.

In the above, the preparation method and application of the manganese / titania catalyst for nitrogen oxide removal according to the present invention have been described. Hereinafter will be described in detail for the embodiment of the present invention. The present invention may be more clearly understood by the following examples, which are intended for the purpose of illustration only and are not intended to limit the scope of the present invention.

Manufacturing example  One

In the preparation of the manganese / titania catalyst for nitrogen oxide removal according to the present invention, the surface charge, specific surface area, pore size, and total pore volume of various titania carriers were measured to select the optimum titania carrier among various commercial titania carriers. manganese nitrate hydrate as the precursor _{(Mn (NO 3) 2 xH} 2 O: Aldrich Chemical Co. in the trade name) or manganese acetate tetrahydrate _{((C 2 H 3 O 2} ) 2 Mn 4 H 2 O: Aldrich Chemical Co. of Brand name) was quantified to 10 wt% based on the weight of the titania carrier, and then dissolved in distilled water heated to 60 ° C. or higher to prepare an aqueous solution of manganese precursor. Subsequently, the manganese precursor aqueous solution and the titania precursor aqueous solution are mixed to prepare a slurry form, and then heated under 70 ° C. and stirring conditions by using a vacuum evaporator, and dried at a temperature of 80 ° C. to 120 ° C. for at least one day. Was removed completely. Finally, manganese / titania catalysts were prepared by firing in a tube furnace, convection furnace, or grate furnace at a temperature of 300-500 ° C. for 0.5-5 hours under an air atmosphere.

Manufacturing example  2

In the preparation of the manganese / titania catalyst for nitrogen oxide removal according to the present invention, a titania carrier having the highest activity is selected, and manganese nitrate hydrate (Mn (NO ₃ ) ₂ x H ₂ O: Aldrich is selected as a manganese precursor to the selected titania carrier. Chemical Co.) or manganese acetate tetra hydrate ((C ₂ H ₃ O ₂ ) ₂ Mn ₄ H ₂ O: brand name of Aldrich Chemical Co.) was quantified to 20wt% based on the weight of the titania carrier 60 ℃ It was dissolved in distilled water heated above to prepare an aqueous solution of manganese precursor. Subsequently, the manganese precursor aqueous solution and the titania precursor aqueous solution were mixed to prepare a manganese / titania catalyst in the same manner as in Preparation Example 1.

Production Example

In the present invention, the carrier to be supported with manganese has a great influence on the NOx removal activity through interaction with the active substance as described above. Therefore, in order to confirm the effect on the nitrogen oxide removal activity when a small amount of cerium oxide having excellent oxygen transfer ability is added to the titania carrier having the best activity in Preparation Example 1, the cerium oxide is supported by 4 to 8 wt% based on the weight of titania. A manganese / titania-seria catalyst was prepared in the same manner as in Preparation Example 1.

Comparative Manufacturing Example

In the present invention, in order to check the effect of excess cerium oxide on the titania carrier on nitrogen oxide removal activity, 20 to 50 wt% of cerium oxide is supported on the basis of the weight of titania. Manganese / Titania A ceria catalyst was prepared.

Example  One

Nitrogen oxide removal characteristics at low temperatures were evaluated for various manganese / titania catalysts prepared by Preparation Example 1 described above. Specifically, the experiment was carried out while maintaining the molar ratio of the supplied ammonia and nitrogen oxides of 1.0, oxygen of 8%, moisture of 8%, space velocity of 60,000hr ^-1 . Correlations with various physicochemical properties of titania carriers are shown in FIGS.

As shown in Figures 1 to 3, even though the same amount of manganese loading and reaction conditions, the nitrogen oxide removal activity shows a great difference according to the specific surface area, pore size and pore volume of the titania carrier, but there is no significant correlation with the nitrogen oxide removal efficiency. It can be seen. In addition, Figure 4 shows the nitrogen oxide removal efficiency of the manganese / titania catalyst according to the various surface charges of titania, from which it can be seen that the zeta potential of titania has a variety of surface charges in the range of -15 ~ 5, As the surface charge increases, the NOx removal efficiency increases, indicating a maximum value at 1.35, but above that, the denitrification efficiency rapidly decreases.

Example  2

The characteristics of nitrogen oxide removal at low temperatures were evaluated for the manganese / titania catalysts and the manganese / titania-ceria catalysts prepared in Preparation Example 2, Example Preparation Examples and Comparative Preparation Examples. Specifically, the experiment was carried out while maintaining the molar ratio of ammonia and nitrogen oxide supplied 1.0, oxygen 8%, moisture 8%, space velocity 60,000hr ^-1 , the conversion rate of nitrogen oxide measured by this method Is shown in Table 1 below.

division NO _X conversion (%) 120 DEG C 140 ° C 160 ° C 180 DEG C Mn / TiO ₂ 22.5 42.5 70 88 Mn / Ce (4) -TiO ₂ 32.5 59.5 79 90.5 Mn / Ce (8) -TiO ₂ 26.5 53.5 76 90.5 Mn / Ce (20) -TiO ₂ 20.5 36.5 56.5 75.5 Mn / Ce (50) -TiO ₂ 17 24 39 54.5

As shown in Table 1, it can be seen that even in the same amount of manganese loading and reaction conditions, there is a large difference in nitrogen oxide removal activity according to the mixing ratio of the cerium oxide mixed with the titania carrier, and in particular, according to the preparation example The manganese / titania-seria catalyst showed good nitrogen oxide removal activity of 80% in the region of 160 ° C., indicating that the activity was increased by 15% or more than the catalyst prepared according to Preparation Example 2. On the other hand, in the case of the manganese / titania-ceria catalyst prepared according to Comparative Preparation Example, rather than the catalyst prepared according to Preparation Example 2 was found to be more than 20% lower activity.

Example  3

The manganese / titania catalyst and the manganese / titania-ceria catalyst prepared by Preparation Example 2, Preparation Example and Comparative Preparation Example described above were subjected to XPS analysis to confirm the oxidation state of manganese. Indicated.

As shown in FIG. 5, the manganese oxidation state of the manganese / titania-ceria catalyst prepared according to the Preparation Example was mainly ⁴⁺ , whereas the manganese oxidation state of the catalyst prepared according to the Comparative Preparation Example was mainly ^3+. It can be seen that it exists as a species. Subsequently, XPS analysis was performed to identify the atoms exposed on the catalyst surface of the catalyst prepared by Preparation Example 2, Example Preparation Example and Comparative Preparation Example, and as a result, the number of atoms per unit volume of the catalyst (atom / cm ³ ) to calculate the atomic% and atomic ratio are shown in the following [Table 2].

division Manufacturing example Production Example Comparative Manufacturing Example Mn / TiO ₂ Mn / Ce (4) -TiO ₂ Mn / Ce (8) -TiO ₂ Mn / Ce (20) -TiO ₂ Mn / Ce (50) -TiO ₂ Mn 8.27 10.22 6.77 6.84 5.21 Ce - 4.04 4.39 7.28 8.91 Ti 18.01 17.75 16.75 15.26 13.53 Mn / Ti 0.46 0.58 0.40 0.45 0.38 Mn / Ce - 2.53 1.54 0.93 0.58 Mn / (Ce + Ti) - 0.47 0.32 0.30 0.23

The Mn / (Ce + Ti) atomic ratio of the catalyst prepared according to the Preparation Example from Table 2 is 0.32 or more, whereas the Mn / (Ce + Ti) atomic ratio of the catalyst prepared according to the Comparative Preparation Example is 0.3 or less. It can be seen that the decrease. This means that addition of cerium oxide to the titania carrier can control not only the oxidation state of manganese, but also the degree of surface exposure of manganese, the active site.

Example  4

For the manganese / titania catalyst and the manganese / titania-ceria catalyst prepared by Preparation Example 2, Preparation Example and Comparative Preparation Example described above, EDS Mapping analysis was performed to more clearly confirm the degree of dispersion of manganese. The results are shown in FIG. As shown in FIG. 6, it can be seen that the catalyst prepared according to the preparation example had the best dispersion of manganese, and the dispersion of manganese of the catalyst prepared according to Preparation Example 2 was low. In contrast, it can be seen that the manganese atoms of the catalyst prepared according to Comparative Preparation Example are mostly exposed but are aggregated.

Subsequently, an ammonia TPD experiment was performed to confirm the effect of the above-described dispersion of manganese on ammonia adsorption, and the results are shown in FIG. 7. As shown in FIG. 7, the catalyst prepared according to the preparation example showed the highest amount of ammonia adsorption, and the ammonia adsorption amount of the catalyst prepared according to the comparative example was very low. This means that the dispersion of manganese is enhanced by the effect of cerium oxide (4-8 wt%) added to the titania carrier and the adsorption point is increased, thereby improving the ammonia adsorption characteristics. That is, the removal efficiency of nitrogen oxides in the flue gas containing moisture and nitrogen oxides is improved by increasing the adsorption site.

Example  5

H ₂ -TPR for the manganese / titania catalyst and the manganese / titania-ceria catalyst prepared by the preparation example 2, the preparation example and the comparative preparation example described above to confirm the reducing power of the catalysts following the dispersion of manganese and the ammonia adsorption amount An experiment was performed and the results are shown in FIG. 8. As shown in Figure 8, the catalyst prepared according to the preparation example can be seen that the reduction temperature is shifted to a low temperature compared to the catalyst prepared according to Preparation Example 2, the catalyst prepared according to the comparative example is the reduction temperature is It can be seen that it moves to high temperature again. This means that the addition of an appropriate amount of ceria improves the reducing capacity of the catalyst, which greatly affects the NOx removal activity.

Claims (11)

In the method for preparing a manganese / titania catalyst by sequentially supporting, drying and calcining the manganese precursor and titania carrier,
The method of manufacturing a manganese / titania catalyst for nitrogen oxide removal further comprising the step of selecting the titania carrier having a zeta potential of 0 to 1.5 by measuring the surface charge of the titania carrier before the supporting process. The method of claim 1,
After mixing cerium oxide on the selected titania carrier, it is supported with the manganese precursor, dried and calcined, wherein the cerium oxide is mixed with 4-8 wt% of the manganese / titania catalyst for removing nitrogen oxides, based on the titania carrier. Manufacturing method. delete 3. The method of claim 2,
The manganese precursor is manganese nitrate hydrate (Mn (NO ₃ ) ₂ x H ₂ O) or manganese acetate tetra hydrate ((C ₂ H ₃ O ₂ ) ₂ Mn ₄ H ₂ O) Manganese for removing nitrogen oxides / Titania catalyst production method. 3. The method of claim 2,
The firing process is a method for producing a nitrogen oxide removal manganese / titania catalyst, characterized in that maintained for 0.5 to 5 hours at a temperature of 300 ~ 500 ℃ in a gas atmosphere containing nitrogen, oxygen. A manganese / titania catalyst for removing nitrogen oxides comprising a titania carrier having a zeta potential of 0 to 1.5 and a manganese precursor dispersed in the titania carrier. The method according to claim 6,
A manganese / titania catalyst for nitrogen oxide removal further comprising cerium oxide supported on the titania carrier based on the titania carrier. The method of claim 7, wherein
Manganese oxide removal manganese / titania catalyst characterized in that the manganese oxide value of the nitrogen oxide removal manganese / titania catalyst 4 ⁺ . The method of claim 7, wherein
A manganese / titania catalyst for removing nitrogen oxides, characterized in that the ratio of manganese atoms exposed to the surface of the nitrogen oxide removal manganese / titania catalyst is at least 0.32. A method for removing nitrogen oxides by passing air containing ammonia and nitrogen oxides or exhaust gas containing water and nitrogen oxides through the manganese / titania catalyst for removing nitrogen oxides according to any one of claims 7 to 9. 11. The method of claim 10,
The method of removing the nitrogen oxides is a method for removing nitrogen oxides, characterized in that made at a temperature of 140 ~ 250 ℃ and space velocity of 60,000hr ^-1 or less.

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