KR100625219B1 - Method for preparing of catalyst filter for purifying exhaust gas of diesel automobile - Google Patents

Abstract

According to the present invention, there is provided a method for producing a catalytic filter for diesel vehicle exhaust gas purification. The catalyst filter manufacturing method includes the steps of undercoating a support solution on the catalyst filter; Drying and firing the undercoated filter catalyst; Coating a noble metal solution; Drying, calcining and reducing the coated precious metal solution. According to the catalyst filter manufacturing method of the present invention, a continuous use of nitrogen oxides is induced to provide a highly active catalyst filter capable of removing particulate matter at low temperature, and oxidation of particles and gaseous contaminants using the catalyst filter provided as described above. By significantly lowering the running temperature, it is possible to minimize the amount of precious metal used for the manufacture of the filter and to save energy for heating the filter bed.

Diesel exhaust gas, catalyst filter, precious metal, support, moisturizer

Description

Method for preparing catalyst filter for purifying exhaust gas of diesel vehicle             

1 is a schematic diagram of an apparatus for removing particulate matter from Johnson Matthey.

2 is an enlarged view of an electron microscope of a surface of a ceramic filter base material coated with a support of an active metal according to the present invention.

3 is an enlarged view of an electron microscope of the surface of the ceramic filter base material not coated with the support of the active metal.

4 is a photograph of a filter completed by coating platinum on a support according to the present invention.

FIG. 5 is a photograph at a magnification of the plane of the filter coated with platinum (FIG. 4) according to the present invention.

6 is a component analysis (EDS) spectrum of the filter surface according to the present invention.

7 is an external view of a catalyst filter manufactured according to Example 1. FIG.

8 is an interior view of a filter manufactured by the coating method according to the prior art.

9 is a cross-sectional view of the filter produced by the coating method according to the prior art.

10 is a graph of experimental results according to Example 2. FIG.

11 is a cross-sectional view of a coating of a catalyst filter depending on whether PVA is added to the coating solution.

The present invention relates to a method for producing a catalyst filter for exhaust gas purification of a diesel vehicle, and more particularly, to coat all external surfaces including the micro channel of the DPF with a support, and subsequently coated with a noble metal to particulate contaminants at low temperature. The present invention relates to a method for manufacturing a catalyst filter for purifying exhaust gas of a diesel vehicle, which can effectively remove the gas.

Diesel vehicles are competitive over gasoline vehicles because of their low fuel consumption and low total emissions due to their superior fuel combustion efficiency. Recently, diesel vehicles have been increasing worldwide due to the development of diesel engine manufacturing technology. In addition, the emission of pollutants is steadily reduced with the development of engine design and manufacturing technology. However, the regulations on pollutants are being tightened, which makes it difficult to satisfy the regulations.

In order to reduce diesel vehicle emissions, various systems using cyclic thermal incineration or continuous regeneration using a catalyst have been tried, but in terms of economics, a continuous regeneration method using an oxidation catalyst has been evaluated as the most effective. In particular, the combination with the filter can achieve high removal efficiency for particulate contaminants. (A. Setiabudi et al., “An optimal NOx assisted abatement of diesel soot in an advanced catalystic filter design,” Appl. Catal. B: Env., 42, 35-45 (2003)).

As a representative system, there may be mentioned a continuous regeneration filter system of Johnson Matthey (Fig. 1). Particulate matter discharged from the diesel engine is trapped in the pores of the surface or wall of the filter, which is transformed into a gas phase by the NO 2 produced according to Scheme 1 by an oxidation catalyst located at the front of the filter and removed (S). Liu et al., “An exploratory study of diesel soot oxidation with NO 2 and O 2 on supported metal oxide catalysts”, Appl. Catal. B: Env., 37, 309-319 (2002)).

Scheme 1

NO + 1/2 O ₂ → NO ₂

Scheme 2

NO ₂ + soot (C) → N ₂ , NO, CO, CO ₂

Scheme 3

O ₂ + Soot (C) → CO, CO ₂

Conventionally, particulate matter has been known to be removed by the combustion reaction of particulate matter on the surface of an oxidation catalyst as in Scheme 3. However, recent research suggests that particulate matter can be removed when nitrogen oxides are used in the low temperature range of 200–300 ° C (Scheme 2). In other words, when using a noble metal catalyst with NO oxidizing power, most of the particulate matter is oxidized by NO ₂ generated by the reaction formula 2 and is removed by catalytic combustion in a high temperature region of 350 ° C. or higher (A. Setiabudi et al. , “An optimal NOx assisted abatement of diesel soot in an advanced catalytic filter design”, Appl. Catal. B: Env., 42, 35-45 (2003)).

Therefore, it is expected to be effective when the nitrogen oxide is actively used when the system is configured for the purpose of maximizing fuel efficiency through the heating inhibition of the filter by performing the low temperature oxidation reaction on particulate matter. For this reason, the rate of generation of NO ₂ in the catalyst layer is a very important factor in the treatment of exhaust gas for diesel engines.

On the other hand, according to the diesel engine type and operating conditions of the prior art, since there is an excessive amount of NOx even after the treatment of particulate contaminants, a separate apparatus for treating the same is required. As shown in FIG. 1, NO ₂ is formed by an oxidation catalyst (DOC) positioned in front of the filter layer (DPF) and passed through the filter layer after being used for the oxidation reaction of soot collected in the DPF. Therefore, it is expected to be the NO ₂ is collected about the relative flow of the small exhaust gas as part of the pressure loss does not generate particulate matter when a gas movement is suppressed in the filter layer by the trapped particulate matter is itself formed in the DOC concentration . Therefore, the amount of NO ₂ , which is an oxidizing agent, appears to be very small in the particulate matter deposition part where a small amount of gas flow exists, and the accumulation of particulate matter is further accelerated. .

In Japanese Patent Laid-Open No. 2004-105792, coating is carried out using a slurry of microparticles of 1 micrometer or less for the purpose of coating the support of the active metal in the DPF pores of 20-40 micrometers, which have a relatively large average porosity, and again prevents macropores. At the same time a method is described for coating a slurry of rather large particles for the purpose of coating a support on the surface of a wall. In this case, however, the coating state is also affected by the average particle size of the particles included in the slurry and its viscosity, and thus, manufacturing is difficult and coating is not possible on the microporous surface of less than 1 micron present in the filter.

Meanwhile, US Patent 4,732,879 discloses a coating method of Al, Si, Ti, and Zr on a three-dimensional structure by the sol-gel method. In this process, since anhydrous alcohol is required as a solvent, a cost problem occurs due to the solvent, and a separate treatment process is required to treat the VOC generated during the drying process.

Korean Patent Application No. 1993-0004735 discloses that even when a precious metal is reduced to alcohol or hydrazine to be prepared in a colloidal state and supported using the same, even distribution of the precious metal can be obtained. At this time, since the alcohol or hydrazine is required as a reducing agent in the reduction process of metal ions, VOC generation in a drying process such as a sol-gel process cannot be avoided.

According to Chun-Wei Chen's research, one method for forming platinum nanoparticles is to reduce platinum by adding chloroplatinic acid to a solution of 40% by volume ethanol and 60% by volume of water to reduce platinum to colloid (1-2 nanometers). ) The manufacturing process has been reported. In order to inhibit the growth of colloidal particles, one of the non-ionic polymers (PVP, PVA, PNVF, PNVA) is required. In addition, reflux heating is required at 70-90 ° C. to supply the activation energy required for reduction (Chun-Wei Chen et al., “Colloidal Platinum Nanoparticles Stabilized by Vinyl Polymer with Amide Side Chains: Dispersion Stability and Catalytic Activity in Aqueous Electirlyte Solutions ", J. Colloid and Interface Science, 225, 349-358 (2000)).

On the other hand, in the prior art, the support is selected from a high surface area Al, Si, Ti, and Zr oxide by slurrying and coating it, and then proceeds in the order of supporting the active metal again or the precious metal is first supported (coated) in the support powder The method of slurrying and coating the surface of the filter is used. However, when the support is slurried or coated with an oxide powder in the coating process of the catalyst, the coating is present only on the surface of the filter. The micro flow path inside the filter is impossible to coat itself. Therefore, there is a problem that the utilization of the catalyst is greatly reduced, the utilization of NOx is low, and in particular, it is impossible to remove nano-sized particulate matter passing through the micropores.

In order to solve this problem of the prior art, the inventors of the present invention coated all the outer surface including the micro-channel of the DPF with a support and subsequently coated with a noble metal to remove particulate contaminants at low temperature as well as occurring in the catalyst layer An object of the present invention is to provide a method for preparing a catalytic filter for purifying exhaust gas of a diesel vehicle which can reuse nitrogen oxide as an oxidant.

According to the invention,

Undercoating the support solution on the catalyst filter of the structure;

Drying and calcining the undercoated support solution;

Coating a noble metal solution on the dry calcined support; And

Drying, calcining and reducing the coated precious metal solution;

It provides a method for producing a catalyst filter for diesel vehicle exhaust gas purification comprising a.

Hereinafter, the present invention will be described in more detail.

According to the present invention, the microporosity of the filter is formed by undercoating, drying, and firing the support solution on all outer surfaces including the microchannel of the DPF, thereby forming a metal oxide as a support, and recoating active precious metal on the surface on which the support is undercoated. There is an advantage in that the coating is possible, and thus prepared catalyst filter can remove particulate and gaseous contaminants in exhaust gas at low temperature, and can provide high oxidation power to hydrocarbons and carbon monoxide.

At least one oxide selected from Al, Si, Ti, and Zr may be used as a support material for the noble metal used in the preparation of the catalyst filter of the present invention. Preferred support oxides include titanium oxide (TiO _x ) and aluminum oxide (Al _2). O ₃ ), silica oxide (SiO ₂ ) and zirconium oxide (ZrO ₂ ). At this time, distilled water is used as a solvent of the coating solution for the support, and an organic or inorganic acid such as acetic acid, oxalic acid, citric acid, hydrochloric acid, or nitric acid is added to ensure solubility of the support precursor. Preferably oxalic acid or citric acid is recommended. In addition, a moisturizer is added to prevent the external diffusion of the metal precursor contained in the solution while delaying the drying rate of the solution. As the moisturizer added to the support solution, at least one nonionic water-soluble polymer having a large number of carbon bonds and having hydrophilic and hydrophobic functional groups is preferably used, but is not limited to polyethylene glycol (PEG) and polyvinylpyrrolidone ( Preference is given to adding at least one compound selected from the group consisting of PVP), polyvinyl alcohol (PVA), polyvinyl formamide (PNVF), polyvinyl acetamide (PNVA) and polyvinyl acrylic acid (PVAA). Do.

In the prior art, in order to suppress the external movement of the ionic metal, a method of controlling the drying rate by using a constant temperature and humidity system is very slow, or by preparing nanoparticles and inducing adsorption to the support, thereby preventing the external movement of the metal. In the present invention, the addition of a moisturizer to the aqueous solution has the advantage that the manufacturing is easy because the drying rate is naturally controlled together with securing accessibility of the precursor in the micropores.

The preparation method of the support solution used for manufacture of the catalyst filter of this invention is as follows. First, at least one support precursor selected from precursors containing titanium, aluminum, silica and zirconium is added to distilled water at 1 to 10% by weight, based on the weight of the total solution, wherein the precursor is transparent to ions or complexes. The form which can maintain a solution state is preferable. Inorganic acid to improve the solubility of the precursor is added in the same molar ratio as the support, followed by polyethylene glycol (PEG), polyvinylpyrrolidone (PVP), polyvinyl alcohol (PVA), polyvinylformamide (PNVF), polyvinylacet A support coating solution is prepared by adding at least one moisturizer selected from the group consisting of amide (PNVA) and polyvinyl acrylic acid (PVAA) at about three times the amount of support added. It is preferable to mix a small amount of lower alcohol in a method for improving the mobility in the micropores by lowering the surface tension of the solution in the process of adding the moisturizing agent. However, unlike the prior art using the sol-gel coating method, it is not necessary to use anhydrous alcohol, and even if a lower alcohol (for example, industrial ethanol) is added, it is sufficient to lower the surface tension of the liquid and 0.1 to 5% by weight based on the total weight. It is preferable to add by.

The support coating solution prepared as described above is absorbed and coated on a three-dimensional structure selected from a ceramic honeycomb filter, a ceramic foam filter, a ceramic fiber filter, a sintered metal metal filter, a metal foam filter, and a metal fiber filter. Remove with air. This process is repeated two more times to ensure that the solution is coated (wet) on all outer surfaces of the DPF catalytic filter. The filter in which the coating solution is absorbed is dried in a dryer at 40-110 ° C. for 3 to 24 hours and then calcined at 500-900 ° C. for 5-10 hours to convert and fix the metal to an oxide with removal of organic matter. It is possible to coat one or more times by adjusting the concentration and viscosity of the solution. For example, when the concentration of the coating solution is low, coating is performed several times. Finally, the coating amount of the support is 1 to 10 g per liter based on the outer volume of the filter. It is preferable to make it. In the coating of the support, in order to maximize the activity of the oxide, it is important to undergo a calcination step at a preferable temperature range. For example, in the case of coating titanium dioxide with a support, its crystal phase is preferably in the form of rutile, which is obtained. It is preferable to bake for 3-20 hours in the range of 700-900 ° C. In addition, when the alumina is coated with a support, it is preferable to fire for 3-20 hours in the range of 750-900 ° C. to have a theta-type crystal structure. In addition, in the case of using aluminum as a support, at least one of Ce, La, and Co is added in an amount of 1 to 10% by weight based on the weight of aluminum in order to obtain high temperature stability, and hexaaluminate is formed through the final firing process. The support of a noble metal can be formed as a form which provided heat resistance.

The noble metal precursor solution is coated on the outer surface of the DPF in the same manner as the coating method of the support. However, in consideration of the exhaust gas temperature depending on the mounting position of the vehicle to be applied, it is necessary to use a single noble metal or a mixture of two or more noble metals or to provide thermal stability of the support as well as a source of oxygen necessary for the oxidation reaction. It is desirable to add one or more of cobalt and lanthanum to adjust the composition to maximize NO oxidation. The noble metal oxidation catalyst used in the catalytic filter coating of the present invention is selected from the group consisting of Pt, Pd, Rh and Ru, wherein chlorite, nitrate, acetonate, acetylacetonate, And noble metal precursors of any form, such as ammonium and the like.

As described above, the noble metal which is the active metal is subsequently coated on the catalyst filter which is undercoated with the metal oxide (the support of the noble metal) and dried and calcined. The preparation method of the noble metal coating solution is as follows. First, at least one selected from the group consisting of Pt, Pd, Rh and Ru is a solution in an aqueous solvent such as distilled water using chlorite, nitrate, acetonate, acetylacetonate, or ammonium form of the oxidation catalyst as a noble metal precursor. It is dissolved by adding 0.1 to 5.0% by weight based on the total weight of the polyethylene glycol (PEG), polyvinylpyrrolidone (PVP), polyvinyl alcohol (PVA), polyvinyl formamide (PNVF), polyvinyl acetate At least one moisturizer selected from the group consisting of amide (PNVA) and polyvinyl acrylic acid (PVAA) is added at 0.1-5.0% by weight, based on the weight of the total solution and oxalic acid, citric acid, Add organic or inorganic acid. At this time, the concentration of the inorganic or organic acid added is added in a molar ratio of 1.5 times or less relative to the noble metal precursor. As in the coating process of the support, the lower alcohol is added in an amount of 0.1 to 5.0% based on the weight of the entire solution to improve the fluidity of the coating solution.

Absorb the noble metal solution to the filter coated with the support of the noble metal using the prepared solution and remove the excess solution using high pressure air, and then dried for 5 to 24 hours in a room temperature -110 ℃ dryer and 500-700 ℃ The mixture was calcined for 3-10 hours in an air atmosphere and then reduced for 1-5 hours in a hydrogen atmosphere at 200-400 ° C. to complete the manufacture of the filter. At this time, it is preferable that the coating amount of the noble metal catalyst is 0.1 to 5.0 g per liter based on the outer volume of the filter.

Thus, the final Pt / TiO _x / cordierite filter according to the catalyst filter manufacturing method of the present invention is shown in FIG. As a result of measuring the removal rate of particulate matter by attaching the catalyst filter manufactured according to the present invention to an automobile (2 liter diesel engine, fuel direct injection type electronic control engine, CRDi), the catalyst filter (FIG. 1) used in the related art was measured. Despite a single DPF system without a DOC, the removal rate was very high, over 93%, and the system volume reduction was achieved.

In addition, the catalyst filter prepared according to the present invention can remove particulate contaminants at low temperature, as well as reuse the nitrogen oxide generated in the catalyst layer as an oxidizing agent, thereby minimizing the amount of precious metal required for the manufacture of the filter and the filter layer. The energy required for heating can be saved. In addition, the production of VOC generated during manufacturing is minimized as compared with the prior art, and by using a moisturizing agent such as a non-ionic aqueous polymer, the movement of the active metal is suppressed and the drying process can be simplified.

The present invention can be more clearly understood by the following examples, the following examples are only for the purpose of illustrating the invention and are not intended to limit the scope of the invention.

Example 1

Corning's DPF filter (2.5 liters, 200 cells) was first coated with titanium dioxide to modify the surface properties of cordierite and then coated the precious metal.

First, a titanium dioxide coating solution was prepared as a support as follows. 67 g of oxalic acid and 450 g of PVP were dissolved in 5 liters of distilled water, and then 150 g of titanium isopropoxide was added thereto to dissolve at room temperature, and then 0.1 liter of ethanol was added thereto. At this time, the amount of oxalic acid is added in the same molar ratio as titanium isopropoxide, PVP is added three times compared to Ti.

The coating solution was absorbed into a filter calcined for 5 hours in an air atmosphere at 800 ° C., and then the coating process was repeated twice to remove excess solution existing in the microchannel of the filter with high pressure air. After drying for 24 hours in a dryer maintained at 80 ℃, 50% relative humidity and then baked for 10 hours in an air atmosphere of 800 ℃ to complete the coating of titanium dioxide, the coating state was confirmed by an electron microscope.

Comparing the inside (Fig. 2) of the coated filter of titanium dioxide in accordance with the coating in the filter base (Fig. 3) and the present invention does not proceed, whereas before the coating of the titanium dioxide hade sharp grain boundaries of cordierite the TiO ₂ In the photograph after coating, the sharpness of each crystal disappeared and the stepped stepped surface filled with the material. That is, it can be seen that TiO _2, which is a support for precious metals, can be effectively coated without losing porosity of the base material. Based on the weight change data of the base material before and after coating, the coating amount of titanium dioxide is 2.5g / liter.

After completing the coating of titanium dioxide as above, the support was coated with a noble metal solution as follows. 5 g of citric acid and 14 g of PVP were dissolved in 430 g of distilled water, and 12.48 g of chloroplatinic acid (H ₂ PtCl ₆ ) was mixed as a precursor of platinum. At this time, the platinum content is mixed to include 1.8 g based on 1 liter of the filter, and the weight of the solution is the weight absorbed by the filter base material of 2.5 liter volume.

The titanium dioxide coated filter was immersed in a platinum solution, a precious metal solution, and the excess solution present in the cell was removed twice using high pressure air, and the dryer was maintained at 80 ° C. for 50% relative humidity. Drying was carried out for 3 hours, calcined for 3 hours in an air atmosphere firing furnace at 700 ° C., and reduced for 2 hours at 300 ° C. hydrogen atmosphere.

The interior of the manufactured DPF under the same conditions is as shown in FIGS. 4 and 5. It can be seen that the same shape as the initial shape of the base material is maintained without clogging pores existing in the plane and cross section of the filter. The concentration of titanium dioxide and platinum on the surface was confirmed by the results of EDS analysis, Ti and Pt as summarized in Figure 6 and Table 1. In particular, it can be seen that the coating of the oxidation catalyst is maintained similar to the initial state of the filter without clogging pores.

TABLE 1

Filter surface analysis data

ingredient Content (wt%) Oxygen 49.93 magnesium 7.39 aluminum 16.48 Silica 23.90 titanium 0.86 iron 1.11 platinum 0.33 Sum 100

The completed catalyst filter was canned. Canning was equipped with one catalytic filter as shown in Figure 7, and the reduction rate of particulate matter and carbon monoxide was measured in the CVS 75 mode for a vehicle equipped with a CR liter engine with a 2-liter displacement. As a result of measurement, particulate matter was 0.118g / km before the catalyst filter was installed, but it was discharged at 0.008g / km after installation to obtain 93.2% removal rate.In addition, carbon monoxide was 0.826g / km before the catalyst filter was installed. Afterwards it was discharged at 0.016g / km to obtain a removal rate of 98.1%.

Example 2

A filter base material as in Example 1 was ground to a powder having a diameter of 0.1 mm or less, and a supported precious metal catalyst was prepared using the same undercoat titanium dioxide solution and precious metal solution. The catalyst was prepared by a catalyst (Pt / TiO ₂ / cordierite) which was coated with a noble metal catalyst (Pt / cordierite) which was not undercoated, and titanium dioxide and then supported on the outer surface.

The method of undercoating titanium dioxide on powder is as follows. Using the prepared coating solution, the precursor solution was added to reach 1% by weight of the support, and dried in a vacuum dryer and then calcined at 800 ° C. for 10 hours to form a titanium dioxide layer. The noble metal precursor was carried and dried in a 105 ℃ dryer, then calcined for 5 hours in an air atmosphere firing furnace of 700 ℃, the reduction was completed for 2 hours in a hydrogen atmosphere of 300 ℃.

For each of the catalysts, 90% by weight of the catalyst and 10% by weight of carbon black (made by Daegu, Germany) as a model reactant of particulate matter were ground and mixed with mortar. This was pressurized to a pressure of 400 tons / cm ² using a metal mold and then prepared by grinding to 40/80 mesh.

The oxidation power of the carbon black was measured for the mixed catalyst in a quartz reactor having an inner diameter of 4 mm. The concentration of carbon dioxide produced while heating at a rate of 0.5 ° C./min from 200 ° C. to 400 ° C. was measured.

The composition of the gas supplied to the reactor was similarly supplied to that of the diesel vehicle exhaust gas. The experiment was carried out under the same conditions of 15 vol% oxygen, 300 ppm of nitrogen monoxide, 5 vol% of moisture, 30 ppmmv of sulfur dioxide, gas supply amount of 100 ml / min, and catalyst loading of 200 mg (SV 40,000 / hr). The concentration of carbon dioxide produced was analyzed by gas chromatography (HP-6890, manufactured by Hewlett-Packard) installed online. The separation column used in the analysis was a capillary column having an internal diameter of 0.530 mm and a length of 30 m, and a thermal conductivity detector (TCD). At this time, hydrogen was used as the analyzer operating gas to improve sensitivity to carbon dioxide.

As a result of the experiment, as shown in the graph of FIG. 10, the catalyst which undercoated titanium dioxide and supported noble metal produced carbon dioxide at low temperature compared with the Pt / cordierite catalyst which did not undercoat titanium dioxide (40 ° C. decrease). . In this way, even if the precious metals of the same type and content are supported, it can be seen that it affects the oxidation reaction of the particulate matter depending on the coating of the support.

Comparative Example 1

The coating solution prepared according to Example 1 was coated on a 300 cell monolith except that no moisturizer was added.

The center of the filter was bisected to observe the internal state of the manufactured filter. In the case of FIG. 11A added with a moisturizer, it is determined that the content of the precious metal coated inside is higher than that of FIG. 11B, but the moisturizer is not added. In case of (b), it can be confirmed that precious metal is concentrated on both the outer surface of the monolith and the ends of the flow path. That is, most of the added precious metals are evaluated to be transferred to the outside with the movement of moisture in the drying process, and this phenomenon is evaluated to be suppressable by the addition of the moisturizing agent.

 Comparative Example 2

A Pt / TiO ₂ catalyst was first prepared, followed by wet milling to prepare a slurry, and then a slurry was coated in a filter (EX-80). An aqueous solution of precursor (H ₂ PtCl ₆ ) was added so that the content of Pt was 1% by weight based on the weight of the support.

TiO ₂ was used as rutile of Aldrich, and an aqueous platinum solution was prepared according to Example 1. Plating process of platinum was prepared in the same process as in Example 2. The slurry was supplied to the filter and the excess coating liquid in the cell was removed by high pressure air. Drying for 24 hours in a dryer (80 ℃, relative humidity 50%), calcined in the air atmosphere (700 ℃, 5 hours), and then reduced (300 ℃ hydrogen atmosphere, 2 hours) to complete the coating of the catalyst filter.

8 and 9 show the results of checking the internal coating state and the coating thickness of the completed filter with an electron microscope. 4 and 5 according to the present invention, most of the coated slurry is present in the form of a cake on the wall surface and it can be seen that there is no catalyst component in the micro or macropores inside the filter wall. Therefore, in the case of the slurry coating method, the oxidation reaction of the particulate matter deposited on the upper end of the catalyst is inevitably the main treatment method. However, since the effect of blocking most of the large pores present on the surface of the filter may be obtained, convenience may be provided in the manufacture of the filter itself, but pressure loss is increased and thus fuel efficiency is reduced. On the other hand, looking at the surface state of Figures 4 and 5 manufactured according to the present invention, since the initial pore shape is maintained in the thin film coating on the surface of the filter can be secured various advantages as compared to the conventional slurry coating method.

All simple modifications and variations of the present invention fall within the scope of the present invention, and the specific scope of the present invention will be apparent from the appended claims.

According to the catalyst filter manufacturing method of the present invention, a continuous use of nitrogen oxides is induced to provide a highly active catalyst filter capable of removing particulate matter at low temperature, and oxidation of particles and gaseous contaminants using the catalyst filter provided as described above. By significantly lowering the running temperature, it is possible to minimize the amount of precious metal used for the manufacture of the filter and to save energy for heating the filter bed.

Claims (13)

(A) Polyethylene glycol (PEG), polyvinylpyrrolidone (PVP), polyvinyl alcohol (PVA), polyvinyl acrylic acid (PVAA), polyvinyl formamide (PNVF) and polyvinyl acetamide (PNVA) Undercoating a support solution containing at least one humectant selected from the group consisting of the catalyst filter; (B) drying and baking the undercoated support solution; (C) On the dry calcined support, polyethylene glycol (PEG), polyvinylpyrrolidone (PVP), polyvinyl alcohol (PVA), polyvinyl acrylic acid (PVAA), polyvinyl formamide (PNVF) and Coating a noble metal catalyst solution containing at least one humectant selected from the group consisting of polyvinylacetamide (PNVA); And (D) drying and calcining the coated noble metal catalyst solution, and then reducing for 1-5 hours in a hydrogen atmosphere at 200-400 ° C. Method for producing a catalytic filter for diesel vehicle exhaust gas purification comprising a. The method of claim 1, wherein the firing step (b) is carried out at a temperature of 700-900 ° C. for 3-20 hours. delete The method of claim 1, wherein the support solution is prepared by adding at least one support precursor selected from precursors containing Ti, Al, Zr and Si in 1 to 10% by weight based on the total weight of the solution Method for producing catalytic filter for diesel exhaust gas purification. The catalyst filter for diesel vehicle exhaust gas purification according to claim 4, wherein when aluminum is used as the support, at least one of Ce, La, and Co in the solution is added in an amount of 1-10% by weight based on the weight of aluminum. Manufacturing method. The method of claim 1, wherein the noble metal catalyst solution is prepared by adding at least one catalyst precursor selected from precursors containing Pt, Pd, Rh and Ru to 0.1-5% by weight based on the total weight of the solution Method for producing a catalytic filter for diesel vehicle exhaust gas purification. The method of claim 6, wherein the noble metal catalyst is used in the form of chlorite, nitrate, acetonate, acetylacetonate, and ammonium and a precursor. delete The catalyst filter for diesel vehicle exhaust gas purification according to claim 1, wherein an organic-inorganic acid selected from the group consisting of acetic acid, oxalic acid, citric acid, hydrochloric acid and nitric acid is added to increase the solubility of the support or the noble metal catalyst solution. Manufacturing method. The diesel vehicle exhaust gas according to claim 1, wherein at least one of methanol, ethanol and propanol is added in an amount of 0.1-5.0 wt% based on the weight of the coating solution in order to improve the fluidity of the support and the noble metal coating solution. Method for producing a catalytic filter for purification. The method of claim 1, wherein the support coating amount is 1 to 10g per liter based on the outer volume of the filter. The method of claim 1, wherein the coating amount of the noble metal is 0.1 to 5.0 g per liter based on the outer volume of the filter. The method of claim 1, wherein the catalytic filter may be a three-dimensional structure, which is selected from the group consisting of ceramic honeycomb filter, ceramic foam filter, ceramic fiber filter, sintered metal metal filter, metal foam filter, and metal fiber filter. Method for producing a catalytic filter for exhaust gas purification of diesel vehicles, characterized in that at least one form.

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