A partition-coated particle capture catalyst and preparation method thereof

Abstract

The present invention belongs to the technical field of automobile exhaust purification catalysts, and specifically relates to a partitioned coated particle capture catalyst and a preparation method thereof. The partitioned coated particle capture catalyst of the present invention comprises a carrier, one end of the carrier is an air inlet end, and the other end is an air outlet end, the air inlet end is provided with a catalytic coating, and the air outlet end is provided with a particle capture coating; the air inlet end catalytic coating comprises ruthenium cerium composite oxide, cerium zirconium composite oxide, yttrium zirconium aluminum composite oxide and a precious metal, and the air outlet end particle capture coating comprises one of aluminum oxide, silicon oxide and titanium oxide. The multi-component catalyst prepared by the present invention introduces ruthenium cerium composite oxide into the catalytic coating, so that it starts to store and release oxygen at a relatively low temperature, thereby rapidly purifying gaseous pollutants, and at the same time, the capture layer undergoes Ostwald ripening migration after high-temperature calcination, blocking the larger-sized pores of the carrier wall, and significantly improving the capture performance of particulate matter in the exhaust gas under the condition of low back pressure growth.

Description

Technical Field

[0001] The invention belongs to the technical field of automobile exhaust purification catalysts, and in particular relates to a partitioned coated particle trapping catalyst and a preparation method thereof. Background Art

[0002] Currently, more and more vehicles are equipped with gasoline engines with GDI technology. Although fuel economy and power have been greatly improved, more gaseous pollutants appear in the cold start phase of the engine, such as HC, CO and NOx, especially HC. Currently, there is no very efficient way to reduce HC emissions for hybrid or pure fuel vehicles. In addition, when the GDI stratified combustion mode is running, more carbon smoke will be generated, which further aggravates the pollution of particulate matter in the air. The current conventional particulate capture catalyst not only has insufficient filtering efficiency but also has large airflow resistance, which greatly reduces fuel economy. Therefore, low-temperature rapid catalysis of gaseous pollutants while reducing particulate matter emissions in exhaust gas has become a research hotspot for multi-catalysts for gasoline vehicles. Summary of the invention

[0003] The purpose of the present invention is to overcome the shortcomings of the prior art in that the catalytic efficiency of low-temperature gaseous pollutants and the particle filtration efficiency are not high enough and the catalyst back pressure is not low enough, and to provide a partitioned coated particle capture catalyst and a preparation method thereof. The partitioned coated particle capture catalyst prepared by the present invention can quickly catalyze the ignition of gaseous pollutants and significantly improve the particle capture performance in the exhaust gas.

[0004] In the first aspect, an embodiment of the present invention provides a partitioned coated particle capture catalyst, comprising a honeycomb wall flow carrier, one end of the honeycomb wall flow carrier is an air inlet end, and the other end of the honeycomb wall flow carrier is an air outlet end, the air inlet end is coated with a catalytic coating, and the air outlet end is coated with a particle capture coating; the air inlet end catalytic coating comprises ruthenium-cerium composite oxide, cerium-zirconium composite oxide, yttrium-zirconium-aluminum composite oxide and a precious metal, and the air outlet end particle capture coating comprises one of aluminum oxide, silicon oxide and titanium oxide.

[0005] Furthermore, the molar ratio of ruthenium element to cerium element in the ruthenium-cerium composite oxide is 1:1-1:2.

[0006] Furthermore, the precious metal includes one or more of platinum, palladium, rhodium and ruthenium, and the loading amount of the precious metal is 1-40g / ft 3 .

[0007] Further, the coating amount of the catalytic coating is 50-160 g / L, and the coating amount of the particle capture coating is 1-40 g / L;

[0008] The weight ratio of the ruthenium-cerium composite oxide to the cerium-zirconium composite oxide in the catalytic coating is 1:3-1:1, and the weight ratio of the cerium-zirconium composite oxide to the yttrium-zirconium-aluminum composite oxide is 1:1-4:1.

[0009] In a second aspect, an embodiment of the present invention provides a method for preparing the partition-coated particle capture catalyst according to the first aspect, comprising the following steps:

[0010] (1) Preparation of catalytic coating slurry: adding cerium-zirconium composite oxide and yttrium-zirconium-aluminum composite oxide to deionized water in sequence according to the coating formula, adding ruthenium-cerium composite oxide after sufficient stirring, and adding one or more of platinum dispersion, palladium solution, rhodium solution and ruthenium solution after sufficient stirring again to obtain catalytic coating slurry;

[0011] (2) Preparation of particle capture coating slurry: according to the coating formula, one or more of aluminum oxide, silicon oxide and titanium oxide are weighed and added into deionized water to obtain a particle capture coating slurry;

[0012] (3) Preparation of a particle capture coating catalyst: According to the coating loading requirement, the particle capture coating slurry described in step (2) is coated on the gas outlet end of the honeycomb wall flow carrier by vacuum suction at one time, and after drying, it is calcined at 950-1050° C. for 2-3 hours to obtain a catalyst semi-finished product containing only the particle capture coating;

[0013] (4) Preparation of catalytic coated catalyst: According to the coating loading requirement, the catalytic coating slurry described in step (1) is coated at one time on the air inlet end of the catalyst semi-finished product containing the particle capture coating obtained in step (3) by vacuum suction, and then dried and calcined at 400-600°C for 3-5 hours to obtain a partitioned coated particle capture catalyst finished product.

[0014] Furthermore, the preparation method of the ruthenium-cerium composite oxide in step (1) comprises the following steps: dissolving a cerium salt in deionized water, then adding a ruthenium salt, and after the cerium salt is completely dissolved, adjusting the pH of the mixed solution system to 9-11 using an alkaline reagent, continuing to stir for 1 hour, standing and aging for 8-10 hours, filtering to obtain a precipitate, washing it with deionized water for 3 times, drying the precipitate in an oven, and then calcining the product to obtain a ruthenium-cerium composite oxide.

[0015] Furthermore, the ruthenium salt is one or more of ruthenium trichloride, ruthenium acetate, tris(4,7-biphenyl-1,10-phenanthroline) ruthenium dichloride and ruthenium nitrate;

[0016] The cerium salt is one or more of cerium acetate, cerium carbonate, cerium sulfate, cerium ammonium nitrate, cerous carbonate dihydrate, cerous oxalate nonahydrate, cerous nitrate hexahydrate and cerous nitrate.

[0017] Furthermore, the alkaline reagent is one or more of ethylamine, ethylenediamine, diethylenetriamine, triethylenetetramine, tetramethylammonium hydroxide, tetraethylammonium hydroxide, monoethanolamine and triethanolamine.

[0018] Furthermore, the method for preparing the platinum dispersion in step (1) comprises the following steps: adding a dispersant into deionized water to form a dispersant solution, and then mixing the platinum solution and the dispersant solution in a weight ratio of 1:5-1:1 and stirring the mixture to obtain a platinum dispersion.

[0019] Further, the dispersant is one or more of acetic acid, citric acid, succinic acid, lactic acid, cellulose acetate, ethyl cellulose, cellulose nitrate, cellulose acetate butyrate, hydroxypropyl cellulose, hydroxyethyl cellulose, cellulose acetate phthalate, glucose, fructose, sucrose, maltose, mannose, rhamnose, sorbitol and trehalose;

[0020] The weight ratio of the dispersant to deionized water in the dispersant solution is 1:3-3:2.

[0021] Compared with the prior art, the technical solution of the embodiment of the present invention has the following beneficial effects:

[0022] The multi-catalyst prepared by the present invention introduces ruthenium-cerium composite oxide into the catalytic coating, so that it starts to store and release oxygen at a relatively low temperature, thereby quickly purifying gaseous pollutants. At the same time, the capture layer undergoes Ostwald ripening migration after high-temperature calcination, blocking the larger pores of the carrier wall, thereby significantly improving the capture performance of particulate matter in the exhaust gas under the condition of relatively low back pressure growth. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 It is a schematic diagram of the structure of the zone-coated particle trap catalyst in an embodiment of the present invention. DETAILED DESCRIPTION

[0024] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0025] The following examples and comparative examples all use a honeycomb wall-flow cordierite carrier with a specification of Φ132.1 mm×127 mm, a pore density of 300 cpsi, a pore wall thickness of 0.2032 mm, and a volume of 1.741 L.

[0026] Example 1

[0027] like Figure 1As shown, a partitioned coated particle capture catalyst comprises a honeycomb wall flow carrier, one end of the honeycomb wall flow carrier is an air inlet end, and the other end of the honeycomb wall flow carrier is an air outlet end, a catalytic coating is arranged at the air inlet end, and the coating amount of the catalytic coating is 90 g / L, and the catalytic coating at the air inlet end comprises ruthenium cerium composite oxide, cerium zirconium composite oxide, yttrium zirconium aluminum composite oxide and precious metals Pt and Rh, the weight ratio of ruthenium cerium composite oxide, cerium zirconium composite oxide and yttrium zirconium aluminum composite oxide is 40:40:20, and the loading amount of Pt is 9 g / ft 3 , the Rh loading is 1.5g / ft 3 ;

[0028] The gas outlet is provided with a particle capture coating, the component of which is silicon oxide, and the coating amount is 5g / L.

[0029] The preparation method of the above partition-coated particle capture catalyst adopts the following process steps:

[0030] (1) Preparation of ruthenium-cerium composite oxide: cerium acetate was weighed and dissolved in deionized water at a molar ratio of ruthenium to cerium of 1:2, and then ruthenium acetate was added. After ruthenium acetate was completely dissolved, the pH of the mixed solution system was adjusted to 9 with ethylenediamine, and the mixture was stirred for 1 hour. The mixture was allowed to stand for 8 hours, and the precipitate was filtered out. The precipitate was washed with deionized water for 3 times, and dried in an oven at 150°C. The product was then calcined at 750°C for 6 hours to obtain a ruthenium-cerium composite oxide.

[0031] (2) Preparation of platinum dispersion: adding acetic acid to deionized water to form a dispersant solution, wherein the weight ratio of acetic acid to deionized water in the dispersant solution is 1:1, and then mixing the Pt(NO3)2 solution and the dispersant solution in a weight ratio of 1:2 and stirring them thoroughly to obtain a platinum dispersion;

[0032] (3) Preparation of catalytic coating slurry: Cerium-zirconium composite oxide and yttrium-zirconium-aluminum composite oxide were added to deionized water in sequence according to the coating amount of 90 g / L. After sufficient stirring, ruthenium-cerium composite oxide was added. After sufficient stirring again, platinum dispersion and Rh(NO3)3 solution (the loading amount of precious metal Pt was 9 g / ft3) were added. 3 , the Rh loading is 1.5g / ft 3 ), after sufficient stirring, a catalytic coating slurry is obtained;

[0033] (4) Preparation of particle capture coating slurry: Weigh silicon oxide according to a coating amount of 5 g / L and add it to deionized water to obtain a particle capture coating slurry;

[0034] (5) Preparation of a particle capture coating catalyst: The particle capture coating slurry prepared in step (4) is coated at a coating amount of 5 g / L on the gas outlet end of the honeycomb wall flow carrier by vacuum suction at one time, dried at 120° C., and then calcined at 950° C. for 2 hours to obtain a catalyst semi-finished product containing only the particle capture coating;

[0035] (6) Preparation of catalytic coated catalyst: The catalytic coating slurry prepared in step (3) is coated at a coating amount of 90 g / L on the air inlet end of the catalyst semi-finished product containing the particle capture coating prepared in step (5) by vacuum suction at one time, and then dried and calcined at 400° C. for 3 hours to obtain a partitioned coated particle capture catalyst finished product.

[0036] Example 2

[0037] like Figure 1 As shown, a partitioned coated particle capture catalyst comprises a honeycomb wall flow carrier, one end of the honeycomb wall flow carrier is an air inlet end, and the other end of the honeycomb wall flow carrier is an air outlet end, a catalytic coating is arranged at the air inlet end, and the coating amount of the catalytic coating is 120 g / L, and the catalytic coating at the air inlet end comprises ruthenium cerium composite oxide, cerium zirconium composite oxide, yttrium zirconium aluminum composite oxide and precious metals Pt and Rh, the weight ratio of ruthenium cerium composite oxide, cerium zirconium composite oxide and yttrium zirconium aluminum composite oxide is 30:45:25, and the loading amount of Pt is 18 g / ft 3 , the Rh loading is 3g / ft 3 ;

[0038] A particle capture coating is provided at the gas outlet end. The component of the particle capture coating is aluminum oxide, and the coating amount is 10 g / L.

[0039] The preparation method of the above partition-coated particle capture catalyst adopts the following process steps:

[0040] (1) Preparation of ruthenium-cerium composite oxide: Weigh cerium carbonate dihydrate in a molar ratio of ruthenium to cerium of 1:1 and dissolve it in deionized water, then add ruthenium trichloride, and after it is completely dissolved, adjust the pH of the mixed solution system to 10 using tetramethylammonium hydroxide, continue stirring for 1 hour, let it stand for 9 hours, filter out the precipitate, wash it with deionized water 3 times, dry it in an oven at 150°C, and then calcine the product at 700°C for 8 hours to obtain a ruthenium-cerium composite oxide;

[0041] (2) Preparation of platinum dispersion: cellulose acetate is added to deionized water to form a dispersant solution, wherein the weight ratio of cellulose acetate to deionized water in the dispersant solution is 1:2, and then the Pt(NO3)2 solution and the dispersant solution are mixed in a weight ratio of 1:3 and stirred thoroughly to obtain a platinum dispersion;

[0042] (3) Preparation of catalytic coating slurry: Cerium-zirconium composite oxide and yttrium-zirconium-aluminum composite oxide were added to deionized water in sequence according to the coating amount of 120 g / L. After sufficient stirring, ruthenium-cerium composite oxide was added. After sufficient stirring again, platinum dispersion and Rh(NO3)3 solution (the loading amount of precious metal Pt was 18 g / ft3) were added. 3 , the Rh loading is 3g / ft 3 ), after sufficient stirring, a catalytic coating slurry is obtained;

[0043] (4) Preparation of particle capture coating slurry: Alumina was weighed and added into deionized water at a coating amount of 10 g / L to obtain a particle capture coating slurry;

[0044] (5) Preparation of particle capture coating catalyst: The particle capture coating slurry prepared in step (4) is coated at a coating amount of 10 g / L on the gas outlet end of the honeycomb wall flow carrier by vacuum suction at one time, dried at 140° C. and then calcined at 1000° C. for 2.5 hours to obtain a catalyst semi-finished product containing only the particle capture coating;

[0045] (6) Preparation of catalytic coated catalyst: According to the coating loading requirement, the catalytic coating slurry prepared in step (3) is coated at one time on the air inlet end of the catalyst semi-finished product containing the particle capture coating prepared in step (5) by vacuum suction, and then dried and calcined at 500° C. for 4 hours to obtain a partitioned coated particle capture catalyst finished product.

[0046] Example 3

[0047] like Figure 1 As shown, a partitioned coated particle capture catalyst comprises a honeycomb wall flow carrier, one end of the honeycomb wall flow carrier is an air inlet end, and the other end of the honeycomb wall flow carrier is an air outlet end, a catalytic coating is arranged at the air inlet end, and the coating amount of the catalytic coating is 140 g / L, and the catalytic coating at the air inlet end comprises ruthenium cerium composite oxide, cerium zirconium composite oxide, yttrium zirconium aluminum composite oxide and precious metals Pt and Rh, the weight ratio of ruthenium cerium composite oxide, cerium zirconium composite oxide and yttrium zirconium aluminum composite oxide is 30:45:25, and the loading amount of Pt is 27 g / ft 3 , the Rh loading is 4.5g / ft 3 ;

[0048] The gas outlet is provided with a particle capture coating, the component of which is titanium oxide, and the coating amount is 25 g / L.

[0049] The preparation method of the above partition-coated particle capture catalyst adopts the following process steps:

[0050] (1) Preparation of ruthenium-cerium composite oxide: Weigh cerium nitrate in a molar ratio of ruthenium to cerium of 1:1 and dissolve it in deionized water. Then add tri(4,7-biphenyl-1,10-phenanthroline)ruthenium dichloride. After it is completely dissolved, adjust the pH of the mixed solution system to 11 with monoethanolamine, continue stirring for 1 hour, let it stand for 10 hours, filter out the precipitate, wash it with deionized water for 3 times, dry it in an oven at 150°C, and then calcine the product at 800°C for 4 hours to obtain ruthenium-cerium composite oxide;

[0051] (2) Preparation of platinum dispersion: fructose is added to deionized water to form a dispersant solution, wherein the weight ratio of fructose to deionized water in the dispersant solution is 1:3, and then the Pt(NO3)2 solution and the dispersant solution are mixed in a weight ratio of 1:4 and stirred to obtain a platinum dispersion;

[0052] (3) Preparation of catalytic coating slurry: Cerium-zirconium composite oxide and yttrium-zirconium-aluminum composite oxide were added to deionized water in sequence according to the coating amount of 140 g / L. After sufficient stirring, ruthenium-cerium composite oxide was added. After sufficient stirring, platinum dispersion and Rh(NO3)3 solution (the loading amount of precious metal Pt was 27 g / ft3) were added. 3 , the Rh loading is 4.5g / ft 3 ), after sufficient stirring, a catalytic coating slurry is obtained;

[0053] (4) Preparation of particle capture coating slurry: titanium oxide was weighed and added into deionized water at a coating amount of 25 g / L to obtain a particle capture coating slurry;

[0054] (5) Preparation of particle capture coating catalyst: The particle capture coating slurry prepared in step (4) is coated at a coating amount of 25 g / L on the gas outlet end of the honeycomb wall flow carrier by vacuum suction at one time, dried at 160° C. and then calcined at 1050° C. for 3 hours to obtain a catalyst semi-finished product containing only the particle capture coating;

[0055] (6) Preparation of catalytic coated catalyst: According to the coating loading requirement, the catalytic coating slurry prepared in step (3) is coated at one time on the air inlet end of the catalyst semi-finished product containing the particle capture coating prepared in step (5) by vacuum suction, and then dried and calcined at 600°C for 5 hours to obtain a partitioned coated particle capture catalyst finished product.

[0056] Comparative Example 1

[0057] A particulate capture catalyst for gasoline vehicles, with a coating amount of 90g / L, La2O3-Al2O3 accounting for 22% of the coating mass, and cerium-zirconium composite oxide accounting for 78% of the coating mass. The composition of La2O3-Al2O3 is: 2wt% lanthanum oxide and 98wt% aluminum oxide; the composition of cerium-zirconium composite oxide is: 75wt% zirconium oxide, 20wt% cerium oxide, 2% lanthanum oxide and 8% neodymium oxide, and the Pt loading is 9g / ft 3 , the Rh loading is 1.5g / ft 3 .

[0058] A method for preparing a particulate capture catalyst for a gasoline vehicle, comprising the following steps:

[0059] (1) Preparation of coating slurry: 300 g La2O3-Al2O3, 300 g cerium-zirconium composite oxide and deionized water were mixed, and then Pt(NO3)2 solution and Rh(NO3)3 solution were added and stirred to obtain a uniformly dispersed PtRh coating slurry (wherein the Pt loading was 9 g / ft 3 , the Rh loading is 1.5g / ft 3 );

[0060] (2) Coating, drying and calcining: The PtRh coating slurry prepared in step (1) was coated on a honeycomb cordierite carrier at a coating amount of 90 g / L, dried at 150°C for 4 hours, and then calcined at 550°C for 4 hours to obtain a PtRh same-layer particle capture catalyst.

[0061] Comparative Example 2

[0062] A particulate capture catalyst for gasoline vehicles, with a coating amount of 140 g / L, La2O3-Al2O3 accounting for 22% of the coating mass, and cerium-zirconium composite oxide accounting for 78% of the coating mass; wherein the composition of La2O3-Al2O3 is: 2wt% of lanthanum oxide and 98wt% of aluminum oxide; the composition of cerium-zirconium composite oxide is: 75wt% of zirconium oxide, 20wt% of cerium oxide, 2% of lanthanum oxide and 8% of neodymium oxide; the loading amount of Pt is 27 g / ft 3 , the Rh loading is 4.5g / ft 3 .

[0063] A method for preparing a particulate capture catalyst for a gasoline vehicle, comprising the following steps:

[0064] (1) Preparation of coating slurry: 600 g La2O3-Al2O3, 1200 g cerium-zirconium composite oxide and deionized water were mixed, and then Pt(NO3)2 solution and Rh(NO3)3 solution were added and stirred to obtain a uniformly dispersed PtRh coating slurry (wherein the Pt loading was 27 g / ft 3 , the Rh loading is 4.5g / ft 3 );

[0065] (2) Coating, drying and calcining: The PtRh coating slurry prepared in step (1) was coated on a honeycomb cordierite carrier at a coating amount of 140 g / L, dried at 150°C for 4 hours, and then calcined at 550°C for 4 hours to obtain a PtRh same-layer particle capture catalyst.

[0066] The catalyst samples prepared in Example 1, Example 2, Example 3, Comparative Example 1 and Comparative Example 2 were subjected to the WLTC cycle vehicle emission test in accordance with the requirements of GB18352.6-2016 "Light-duty Vehicle Pollutant Emission Limits and Measurement Methods (China Phase VI)". The emissions of gaseous pollutants CO, THC and NOx were directly measured, and the particle capture rate was calculated based on the original emission of particulate matter (particulate matter directly discharged after the combustion of the automobile engine, calculated as 2.50×10 12 The gaseous pollutant emission and particulate matter emission tests of each embodiment were conducted 3 times, and the average value was taken as the final result. The emission test comparison is shown in Table 1.

[0067] Table 1 Comparison of vehicle pollutant emissions

[0068]

[0069] Table 1 The vehicle pollutant emission test results show that the THC, CO and NO in Example 1, Example 2 and Example 3 X The purification efficiency is significantly higher than that of Comparative Example 1 and Comparative Example 2, and the particle capture rate is significantly improved.

[0070] Finally, it should be noted that the above specific implementation methods are only used to illustrate the technical solution of the present invention rather than to limit it. Although the present invention has been described in detail with reference to examples, those skilled in the art should understand that the technical solution of the present invention can be modified or replaced by equivalents without departing from the spirit and scope of the technical solution of the present invention, which should be included in the scope of the claims of the present invention.

Claims

1. A zone-coated particle trap catalyst, characterized in that: It comprises a honeycomb wall flow type carrier, one end of the honeycomb wall flow type carrier is an air inlet end, the other end of the honeycomb wall flow type carrier is an air outlet end, the air inlet end is coated with a catalytic coating, and the air outlet end is coated with a particle trapping coating; the air inlet end catalytic coating comprises ruthenium-cerium composite oxide, cerium-zirconium composite oxide, yttrium-zirconium-aluminum composite oxide and precious metals, and the air outlet end particle trapping coating comprises one or more of aluminum oxide, silicon oxide and titanium oxide; The weight ratio of the ruthenium-cerium composite oxide to the cerium-zirconium composite oxide in the catalytic coating is 1:3-1:1, the weight ratio of the cerium-zirconium composite oxide to the yttrium-zirconium-aluminum composite oxide is 1:1-4:1, and the molar ratio of the ruthenium element to the cerium element in the ruthenium-cerium composite oxide is 1:1-1:2; The method for preparing the partition-coated particle trap catalyst comprises the following steps: (1) Preparation of catalytic coating slurry: adding cerium-zirconium composite oxide and yttrium-zirconium-aluminum composite oxide to deionized water in sequence according to the coating formula, adding ruthenium-cerium composite oxide after sufficient stirring, and adding one or more of platinum dispersion, palladium solution, rhodium solution and ruthenium solution after sufficient stirring again to obtain catalytic coating slurry; (2) Preparation of particle capture coating slurry: according to the coating formula, one or more of aluminum oxide, silicon oxide and titanium oxide are weighed and added into deionized water to obtain a particle capture coating slurry; (3) Preparation of a particle capture coating catalyst: According to the coating loading requirement, the particle capture coating slurry described in step (2) is coated on the gas outlet end of the honeycomb wall flow carrier by vacuum suction at one time, and after drying, it is calcined at 950-1050° C. for 2-3 hours to obtain a catalyst semi-finished product containing only the particle capture coating; (4) Preparation of catalytic coating catalyst: according to the coating loading requirement, the catalytic coating slurry described in step (1) is coated at one time on the air inlet end of the catalyst semi-finished product containing the particle trapping coating obtained in step (3) by vacuum suction, and then dried and calcined at 400-600° C. for 3-5 hours to obtain a partitioned coated particle trapping catalyst finished product; The preparation method of the ruthenium-cerium composite oxide described in step (1) comprises the following steps: dissolving a cerium salt in deionized water, then adding a ruthenium salt, and after the cerium salt is completely dissolved, adjusting the pH of the mixed solution system to 9-11 using an alkaline reagent, continuing to stir for 1 hour, standing and aging for 8-10 hours, filtering to obtain a precipitate, washing it with deionized water for 3 times, drying the precipitate in an oven, and then calcining the product to obtain a ruthenium-cerium composite oxide.

2. The zoned coated particle trap catalyst according to claim 1, characterized in that: The precious metal includes one or more of platinum, palladium, rhodium and ruthenium, and the loading amount of the precious metal is 1-40g / ft 3 .

3. The zoned coated particle trap catalyst according to claim 1, characterized in that: The coating amount of the catalytic coating is 50-160 g / L, and the coating amount of the particle capture coating is 1-40 g / L.

4. The zoned coated particle trap catalyst according to claim 1, characterized in that: The ruthenium salt is one or more of ruthenium trichloride, ruthenium acetate, tris(4,7-biphenyl-1,10-phenanthroline) ruthenium dichloride and ruthenium nitrate; The cerium salt is one or more of cerium acetate, cerium carbonate, cerium sulfate, cerium ammonium nitrate, cerous carbonate dihydrate, cerous oxalate nonahydrate, cerous nitrate hexahydrate and cerous nitrate.

5. The zoned coated particle trap catalyst according to claim 1, characterized in that: The alkaline reagent is one or more of ethylamine, ethylenediamine, diethylenetriamine, triethylenetetramine, tetramethylammonium hydroxide, tetraethylammonium hydroxide, monoethanolamine and triethanolamine.

6. The zoned coated particle trap catalyst according to claim 1, characterized in that: The method for preparing the platinum dispersion in step (1) comprises the following steps: adding a dispersant into deionized water to form a dispersant solution, and then mixing the platinum solution and the dispersant solution in a weight ratio of 1:5-1:1 and stirring the mixture to obtain a platinum dispersion.

7. The zoned coated particle trap catalyst according to claim 6, characterized in that: The dispersant is one or more of acetic acid, citric acid, succinic acid, lactic acid, cellulose acetate, ethyl cellulose, cellulose nitrate, cellulose acetate butyrate, hydroxypropyl cellulose, hydroxyethyl cellulose, cellulose acetate phthalate, glucose, fructose, sucrose, maltose, mannose, rhamnose, sorbitol and trehalose; The weight ratio of the dispersant to deionized water in the dispersant solution is 1:3-3:2.

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