Catalysts with noble metals supported at grain boundaries and on surfaces, methods for producing the same, and applications.

Abstract

The present invention relates to a catalyst carrying a precious metal on the grain boundaries and surface, and its manufacturing method and use. The catalyst carries a precious metal on the grain boundaries and surface of an active coating containing alumina and / or cerium-zirconium composite oxide, thereby improving the anchoring effect of the precious metal, preventing the migration, aggregation and growth of precious metal particles, maintaining the catalytic activity and high-temperature stability of the precious metal catalyst, and reducing the amount of precious metal used.

Description

[Technical Field]

[0001] <Cross-reference of related applications> This application is filed pursuant to and claims priority from the said Chinese patent application No. 202210135425.8, filed on 14 February 2022, and all contents of the said Chinese patent application are incorporated herein by reference.

[0002] The present invention relates to the technical field of noble metal catalysts, and more particularly to catalysts in which noble metals are supported at grain boundaries and on surfaces, methods for producing the same, and applications thereof. [Background technology]

[0003] Research shows that with the yearly increase in the number of vehicles worldwide, automobile exhaust pollution has become a major source of urban air pollution, and environmental problems caused by automobile exhaust emissions are becoming increasingly serious. Automotive catalytic converters are an effective solution for purifying automobile exhaust gases, and their core is a three-way catalyst supported by precious metals. Typically, an automotive three-way catalyst consists of a honeycomb support, precious metals, and an active coating. Its service life is mainly determined by the active coating material and manufacturing process of the three-way catalyst, which may contain cerium zirconium composite oxide and alumina, with the precious metals supported on the active coating. In actual applications, the environment in which automotive three-way catalysts are placed is harsh, containing not only water vapor but also high temperatures, sometimes reaching over 900°C. Therefore, high-temperature stability is required for the catalyst, coating material, and precious metals. Therefore, in order to ensure the conversion efficiency of automotive exhaust gas catalysts and maintain the catalytic activity of cerium zirconium composite oxide-supported precious metal catalysts, high-temperature aging of the coating material containing cerium zirconium-supported precious metals in high-temperature environments should be prevented as much as possible. On the other hand, high-temperature sintering of cerium zirconium should be prevented as much as possible. On the other hand, migration, aggregation, growth, or reduction or loss of catalytic activity due to being encased in coating materials such as cerium zirconium or alumina at high temperatures of precious metal particles should be prevented. High high-temperature stability is also required for oxidation-type catalysts such as natural gas catalytic combustion and organic exhaust gas treatment. [Overview of the project] [Problems that the invention aims to solve]

[0004] Based on the above-mentioned conditions of the prior art, the object of the present invention is to provide a catalyst with noble metals supported on grain boundaries and surfaces, a method for producing the same, and its uses. By dispersing noble metals on the grain boundaries and surfaces of alumina and / or cerium zirconium composite oxide, it is used to inhibit or delay elemental diffusion between grains and on the surface, suppressing the movement, aggregation, and growth of noble metal particles at high temperatures, thereby producing a cerium zirconium-based noble metal catalyst that is more resistant to high temperatures and more stable. Furthermore, by using the catalyst with noble metals supported on the grain boundaries and surfaces of alumina and / or cerium zirconium composite oxide produced as described above in the production of a honeycomb-type noble metal catalyst slurry, and by applying the slurry to a honeycomb to produce a honeycomb-type noble metal catalyst, the high-temperature resistance stability of the honeycomb-type noble metal catalyst is effectively improved, the catalytic activity of the catalyst under high-temperature, long-term use conditions is maintained, and the amount of noble metal used is reduced. [Means for solving the problem]

[0005] To achieve the above objective, according to a first aspect of the present invention, a catalyst is provided in which a noble metal is supported at grain boundaries and on the surface, the catalyst comprising a noble metal G, alumina and / or cerium zirconium composite oxide, wherein the noble metal G is dispersed at grain boundaries and on the surface of the alumina and / or cerium zirconium composite oxide, and the general chemical formula of the cerium zirconium composite oxide is Ce x Zr y M z O 2-α D δ And here, M is the cation doping element, and D is the anion doping element. 0≦x≦1, 0≦y≦1, 0≦z<0.5, and x, y, and z satisfy x+y+z=1. 0≦α≦0.1 and 0≦δ≦0.1.

[0006] According to a second aspect of the present invention, a honeycomb-type precious metal catalyst is provided, the catalyst comprising a honeycomb support, a precious metal G, and an active coating, the active coating being alumina and / or cerium zirconium composite oxide Ce x Zr y Mz O 2-α D δ wherein the noble metal G is dispersed in the grain boundaries and on the surface of alumina and / or cerium-zirconium composite oxide, and M is a cationic doping element, D is an anionic doping element, 0≤x≤1, 0≤y≤1, 0≤z<0.5, and x, y, z satisfy x+y+z=1, 0≤α≤0.1, 0≤δ≤0.1.

[0007] Further, the percentage of the cerium-zirconium composite oxide relative to the total mass of the active coating is 0 to 100%, preferably 30 to 70%.

[0008] Further, the noble metal G at the grain boundaries and on the surface is in a metallic state, or in a metallic state and an oxidized state.

[0009] Further, the noble metal G comprises one or a combination of two or more selected from the group consisting of Pt, Pd, Rh, Ir, Os, Ru, Au and Ag, and is preferably one or a combination of two or more selected from the group consisting of Pt, Pd, Rh and Ru.

[0010] Further, the doping element M is one or a combination of two or more selected from the group consisting of rare earth elements other than cerium, zirconium, transition metal elements other than rare earths, alkaline earth metal elements, Al, Si, Ga, Sn and Bi; the rare earth elements other than cerium comprise La, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu and Y, and are preferably La, Pr, Nd, Sm, Eu, Gd, Tm, Yb and Y; the transition metal elements comprise Sc, Ti, V, Mn, Fe, Co, Ni, Cu, Zn, Nb, Mo, Hf, Ta and W, and are preferably Ti, Mn, Fe, Co, Ni, Cu, Nb, Hf, W and Mo; the alkaline earth metal elements comprise Be, Mg, Ca, Sr and Ba, and are preferably Mg, Sr and Ba; the doping element D comprises one or a combination of two or more of anionic N, F and P.

[0011] Furthermore, the cerium zirconium composite oxide in the catalyst includes a core-shell structure, where the core contains rare earth elements and zirconium elements, and the yttria content in the shell is higher than the total yttria content in the composite oxide. The present invention designs the elemental types and content of the shell and / or core based on the theoretically calculated difference between elemental surface energy and oxygen vacancy formation energy, thereby comprehensively improving the thermal stability and oxygen storage and release performance of the cerium zirconium composite oxide.

[0012] Furthermore, the cerium zirconium composite oxide in the catalyst contains cerium zirconium oxide with an elemental gradient distribution structure. Based on the theoretically calculated difference between elemental surface energy and oxygen vacancy formation energy, the present invention designs the types and content of elements in the gradient structure, and gradually increases or decreases the content of specific elements from the inside to the outside in the radial direction of the crystal grains, thereby comprehensively improving the thermal stability and oxygen storage and release performance of the cerium zirconium composite oxide.

[0013] Furthermore, the material of the honeycomb carrier is porous ceramic or metal.

[0014] Furthermore, the amount of noble metal G supported in the catalyst is 0.01% to 3% by mass fraction, preferably 0.1% to 2%.

[0015] Furthermore, the amount of noble metal G supported in the catalyst is 0.01 to 2.8 g / L, preferably 0.1 to 2 g / L.

[0016] According to a third aspect of the present invention, a method for producing a catalyst with noble metals supported on grain boundaries and surfaces as described in the first aspect of the present invention is provided. Step S1 involves uniformly mixing a cerium zirconium composite oxide and / or activated alumina with a liquid salt of noble metal G, Step S2 involves performing one or two heat treatments on the product obtained in step S1, Step S3 comprises reducing and roasting the product obtained in step S2 once or twice in air or a reducing atmosphere to obtain a catalyst in which a noble metal is supported at the grain boundaries and surface of cerium zirconium composite oxide and / or activated alumina.

[0017] According to a fourth aspect of the present invention, a method for producing a honeycomb-type precious metal catalyst described in a second aspect of the present invention is provided, wherein one or more coating materials are applied to the honeycomb-type precious metal catalyst in layers or regions, the coating material being a mixture of cerium zirconium composite oxide, alumina, grain boundaries and surface supported with a precious metal, alumina with a precious metal supported on the grain boundaries and surface, cerium zirconium composite oxide and alumina with a precious metal supported on the grain boundaries and surface, and the production of the honeycomb-type precious metal catalyst is as follows: Step B1 involves uniformly mixing the aforementioned coating material with an adhesive, an acidity adjuster, and water in one or more steps to produce a coating slurry. Step B2 involves applying the coating slurry obtained in step B1 to the honeycomb carrier in one or more steps, or applying it to the honeycomb carrier region by region or layer by layer, and then drying it. Step B3 involves heat-treating and / or roasting the product obtained in step B2 in air or a reducing atmosphere to obtain a noble metal honeycomb catalyst.

[0018] According to a fifth aspect of the present invention, a method for producing a honeycomb-type precious metal catalyst as described in the second aspect of the present invention is provided, comprising: uniformly mixing cerium zirconium composite oxide and / or alumina, a liquid salt of a precious metal, an adhesive, an acidity adjuster, and water in one or more steps to produce a coating slurry; coating the obtained product onto a honeycomb support in one or more steps, or coating it onto the honeycomb support region by region or layer by layer and drying; and heat-treating and / or reducing-roasting the dried honeycomb support in a reducing atmosphere to obtain a honeycomb-type precious metal catalyst.

[0019] Furthermore, the heat treatment temperature is 200 to 800°C, the heat treatment time is 0.5 to 24 hours, preferably the heat treatment temperature is 400 to 700°C, and preferably the heat treatment time is 1 to 12 hours.

[0020] Furthermore, the roasting temperature is 400 to 700°C, the time is 0.5 to 24 hours, preferably the roasting temperature is 450 to 600°C, and preferably the roasting time is 1 to 12 hours.

[0021] Furthermore, the reducing atmosphere contains one or more of CO and H2.

[0022] Furthermore, the liquid salt of the precious metal G includes one or more combinations of molten salts or aqueous solutions of chlorides, nitrates, and acetates.

[0023] According to a sixth aspect of the present invention, applications of the catalyst described in the first and second aspects of the present invention are provided in the fields of automobile exhaust gas purification, industrial organic exhaust gas treatment, natural gas catalytic combustion, petrochemicals, hydrogen energy, and batteries. [Effects of the Invention]

[0024] As described above, the present invention provides a catalyst with a precious metal supported on its grain boundaries and surface, a honeycomb-type precious metal catalyst, a method for producing the same, and its applications. The catalyst with a precious metal supported on its grain boundaries and surface and the honeycomb-type precious metal catalyst provided in the present invention improve the anchoring action of the precious metal by dispersing the precious metal G on the grain boundaries and surface of alumina and / or cerium zirconium composite oxide, thereby avoiding migration, aggregation, and growth of precious metal particles, maintaining the catalytic activity and high-temperature stability of the precious metal catalyst, and reducing the amount of precious metal used. [Brief explanation of the drawing]

[0025] [Figure 1] This is a flowchart of a method for producing a catalyst in which noble metals are supported at grain boundaries and on the surface, according to an embodiment of the present invention. [Figure 2] This is a flowchart of the method for producing a honeycomb-type precious metal catalyst according to an embodiment of the present invention. [Modes for carrying out the invention]

[0026] To further clarify the object, technical concept and advantages of the present invention, the invention will be described in more detail below with reference to the accompanying drawings and in relation to specific embodiments. It should be understood that these descriptions are illustrative and do not limit the scope of the invention. Furthermore, in order to avoid unnecessary confusion of the concepts of the present invention, descriptions of known structures and techniques will be omitted in the following description.

[0027] Examples of the present invention provide a catalyst in which a noble metal is supported at the grain boundaries and on the surface, wherein the noble metal G is dispersed at the grain boundaries and on the surface of alumina and / or cerium zirconium composite oxide, where the general chemical formula of the cerium zirconium composite oxide is Ce x Zr y M z O 2-α D δ Here, M is the cation doping element, D is the anion doping element, and the range of values ​​for each element is as follows: 0≦x≦1, 0≦y≦1, 0≦z≦0.5, and x, y, and z satisfy x+y+z=1. 0≦α≦0.1 and 0≦δ≦0.1.

[0028] Embodiments of the present invention further provide a honeycomb-type precious metal catalyst, the catalyst comprising a honeycomb support, a precious metal G, and an active coating, the active coating being alumina and / or cerium zirconium composite oxide Ce x Zr y M z O 2-α D δ The noble metal G is alumina and / or cerium zirconium composite oxide Ce x Zr y M z O 2-α D δ The noble metal G is dispersed at the grain boundaries and on the surface, and the noble metal G is in a metallic state, or in a metallic state and an oxidized state, preferably in a metallic state, and the noble metal G is alumina and / or cerium zirconium composite oxide Ce x Zr y M z O 2-α Dδ The noble metal G is dispersed at the grain boundaries and on the surface of the active coating and is in a metallic state, which is advantageous due to its catalytic effect. The noble metal G may be one or a combination of one or more of Pt, Pd, Rh, Ir, Os, Ru, Au, and Ag, preferably one or a combination of one or more of Pt, Pd, Rh, and Ru, and the amount of noble metal G supported in the catalyst is 0.01 to 3% by mass fraction, preferably 0.1 to 2%.

[0029] The cerium zirconium composite oxide doping element M of the present invention is one or more combinations of rare earth elements other than cerium, zirconium and transition metal elements other than rare earth elements, alkaline earth metal elements, Al, Si, Ga, Sn, and Bi, wherein the rare earth elements other than cerium include La, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, and Y, preferably La, Pr, Nd, Sm, Eu, Gd, The elements are Tm, Yb, and Y, the transition metal elements include Sc, Ti, V, Mn, Fe, Co, Ni, Cu, Zn, Nb, Mo, Hf, Ta, and W, preferably Ti, Mn, Fe, Co, Ni, Cu, Nb, Hf, W, and Mo, the alkaline earth metal elements include Be, Mg, Ca, Sr, and Ba, preferably Mg, Sr, and Ba, and the doping element D may be one or more of the anions N, F, and P.

[0030] The cerium zirconium composite oxide in the catalyst provided in the embodiments of the present invention includes a core-shell structure. For other features and advantages of the core-shell structure of the cerium zirconium composite oxide, please refer to the Chinese patent application filed on September 17, 2020, application number CN202010982980.5, title of invention, "Cerium Zirconium-Based Composite Oxide with Core-Shell Structure and Method for Producing the Same," and its full description. The present invention designs the elemental types and content of the shell and / or core based on the difference between the theoretically calculated elemental surface energy and the oxygen vacancy formation energy, thereby comprehensively improving the thermal stability and oxygen storage and release performance of the cerium zirconium composite oxide.

[0031] The cerium zirconium composite oxide in the catalyst provided in the embodiments of the present invention includes a cerium zirconium composite oxide with an elemental gradient distribution structure. For other features and advantages of the elemental gradient distribution structure of the cerium zirconium composite oxide, please refer to the Chinese patent application filed on September 17, 2020, application number CN202010982979.2, titled "Cerium Zirconium-Based Composite Oxide with Elemental Gradient Distribution and Method for Producing the Same," and its full description. The present invention designs and controls the types and content of elements in the gradient structure based on the theoretically calculated difference between elemental surface energy and oxygen vacancy formation energy, gradually increasing or decreasing the content of specific elements from the inside to the outside in the radial direction of the crystal grains, thereby comprehensively improving the thermal stability and oxygen storage and release performance of the cerium zirconium composite oxide.

[0032] The embodiments of the present invention further provide a method for producing a catalyst on which noble metals are supported at grain boundaries and on the surface. Figure 1 shows a flowchart of the method for producing a catalyst on which noble metals are supported at grain boundaries and on the surface according to the embodiments of the present invention, and includes steps S1 to S3.

[0033] In S1, alumina and / or cerium zirconium composite oxide Ce are mixed in a predetermined composition ratio. x Zr y M z O 2-α D δ The liquid salt of the noble metal G is uniformly mixed, and the liquid salt of the noble metal G includes one or more combinations of molten salts or solutions of chloride, nitrate, or acetate, and the alumina and / or cerium zirconium composite oxide Ce in this step. x Zr y M z O 2-α D δ The mixing ratio of the material to the precious metal G is 0.01 to 3% by mass fraction, preferably 0.1 to 2%, depending on the amount of precious metal G supported.

[0034] In step S2, the product obtained in step S1 is subjected to one or two heat treatments, the temperature of which may be 200 to 800°C, the duration 0.5 to 24 hours, preferably the heat treatment temperature 400 to 700°C and the heat treatment duration 1 to 12 hours.

[0035] In step S3, the product obtained in step S2 is reduced and roasted once or twice in air or a reducing atmosphere to form alumina and / or cerium zirconium composite oxide Ce x Zr y M z O 2-α D δ A catalyst is obtained in which noble metals are dispersed at the grain boundaries and on the surface, the roasting temperature may be 400 to 800°C, the time 0.5 to 24 hours, preferably the roasting temperature 450 to 600°C and the roasting time 1 to 12 hours, the reducing atmosphere may contain one or more of CO and H2, and the reducing atmosphere may contain a small amount of O2, with the volume percentage content of O2 being 10% or less.

[0036] In the embodiments of the present invention, when performing heat treatment in step S2, by controlling the appropriate temperature, the grain boundaries of the substrate are activated and become paths for the diffusion of the noble metal, and by controlling the heat treatment time, the depth and distribution of diffusion of the noble metal along the grain boundaries can be controlled. In step S3, by controlling the reducing atmosphere, reduction temperature, and reduction time, the noble metal at the grain boundaries and surface can be reduced, or controlled to be partially reduced. By distributing the noble metal at the grain boundaries and surface of the cerium zirconium composite oxide in steps S2 and S3, on the one hand, elemental diffusion between crystal grains or on the surface of the cerium zirconium composite oxide is inhibited or delayed, preventing sintering aging and a decrease in specific surface area of ​​the cerium zirconium composite oxide, and increasing the thermal stability of the cerium zirconium composite oxide. On the other hand, the anchoring effect of the noble metal by the grain boundaries and surface of the cerium zirconium composite oxide delays the movement, aggregation, and growth of noble metal particles at high temperatures, resulting in a more high-temperature resistant and stable alumina and / or cerium zirconium composite oxide Ce x Zr yM z O 2-α D δ A catalyst is manufactured in which a noble metal is supported at the grain boundaries and on the surface.

[0037] An embodiment of the present invention further provides a method for producing the above-mentioned honeycomb-type precious metal catalyst, wherein one or more coating materials are applied to the honeycomb-type precious metal catalyst in layers or regions, and the coating material is a mixture of cerium zirconium composite oxide, alumina, grain boundaries and surface supported cerium zirconium composite oxide, alumina with a precious metal supported grain boundaries and surface, cerium zirconium composite oxide and alumina with a precious metal supported grain boundaries and surface, and Figure 2 shows a flowchart of the method for producing the honeycomb-type precious metal catalyst according to the embodiment of the present invention. Step B1 involves uniformly mixing the aforementioned coating material with an adhesive, an acidity adjuster, and water in one or more steps to produce a coating slurry. Step B2 involves applying the coating slurry obtained in step B1 to the honeycomb carrier in one or more steps, or applying it to the honeycomb carrier region by region or layer by layer, and then drying it. Step B3 includes heat treatment and / or roasting of the product obtained in step B2 to obtain a noble metal honeycomb catalyst, wherein the heat treatment temperature in step B2 may be 200 to 800°C, the time 0.5 to 24 hours, preferably the heat treatment temperature 400 to 700°C and the heat treatment time 1 to 12 hours, the roasting temperature in step B3 may be 400 to 800°C, the time 0.5 to 24 hours, preferably the roasting temperature 450 to 600°C and the roasting time 1 to 12 hours, and the roasting atmosphere in step B3 may be air atmosphere roasting or reducing atmosphere roasting, and the atmosphere for reducing roasting may be selected from one or more of CO and H2.

[0038] The embodiments of the present invention further provide another method for producing the above-mentioned honeycomb-type precious metal catalyst, comprising the following steps: applying one or more combinations of catalysts, including cerium zirconium composite oxide, alumina, cerium zirconium composite oxide, and / or activated alumina, with precious metals supported at the grain boundaries and on the surface, to a honeycomb carrier in layers or regions; and obtaining a honeycomb-type precious metal catalyst with precious metal G supported at the grain boundaries and on the surface of alumina and / or cerium zirconium composite oxide by a heat treatment step and a roasting step, and by controlling the atmosphere, temperature and time of the heat treatment and roasting. The anchoring action of the precious metal by the grain boundaries and surface prevents the movement and growth of precious metal particles, thereby maintaining the catalytic activity and high-temperature stability of the precious metal catalyst, improving the thermal stability performance of the honeycomb-type precious metal catalyst under long-term high-temperature environmental conditions, ensuring the catalytic activity of the catalyst, and reducing the amount of precious metal used.

[0039] The embodiments of the present invention further provide applications for the catalysts with noble metals supported on grain boundaries and surfaces, and the honeycomb-type noble metal catalysts, in the fields of automotive exhaust gas purification, industrial organic exhaust gas treatment, natural gas catalytic combustion, petrochemicals, hydrogen energy, and batteries. The catalysts with noble metals supported on grain boundaries and surfaces and the honeycomb-type noble metal catalysts provided in the embodiments of the present invention exhibit good high-temperature stability and can meet the application needs of the relevant fields.

[0040] The present invention will be further described below with reference to specific examples.

[0041] (Comparative Example 1) A fixed volume of palladium nitrate and platinum nitrate solution with a loading of 0.9% palladium and 0.3% platinum is measured out, and 200g Ce 0.52 Zr 0.36 La 0.05 Y 0.07 The sample was homogeneously mixed with O2 powder, dried at 110°C for 4 hours, and then roasted in an air atmosphere at 500°C for 5 hours to obtain a cerium zirconium-supported precious metal catalyst sample. An appropriate amount of cerium zirconium composite oxide-supported precious metal catalyst sample, prepared as described above, was aged at 1000°C for 4 hours. The cerium zirconium composite oxide-supported precious metal catalyst powder was then compressed, crushed, and sieved to obtain granular cerium zirconium composite oxide-supported precious metal catalyst with a mesh size of 30-40. Subsequently, catalyst performance tests were conducted on the granular catalyst. For the catalyst test, a simulated automobile exhaust gas mixture was used, with the content (volume ratio) of each component being 1.5% CO, 900 ppm NO, 900 ppm HC, 1.2% O2, 12% CO2, and the remainder being N2, with a space velocity of 50000 / h. The ignition temperatures (T50) of the samples for catalytic conversion of CO, NO, and HC were tested, and the results showed that the ignition temperature of CO was 325°C, the ignition temperature of NO was 339°C, and the ignition temperature of HC was 318°C.

[0042] (Comparative Example 2) 200g Ce 0.52 Zr 0.36 La 0.05 Y 0.07 A slurry was prepared from O2 powder, 200 g of activated alumina, and an appropriate amount of deionized water. Palladium nitrate and platinum nitrate were added in amounts of 0.45% palladium and 0.15% platinum relative to the total mass of the honeycomb carrier activated coating, and mixed uniformly. An adhesive and an acidity adjuster were then added to prepare a coating slurry. The slurry, prepared with a total loading amount of honeycomb catalyst precious metal of 1.2 g / L, was applied to a ceramic honeycomb carrier. The coated honeycomb carrier was dried at 110°C for 4 hours, and finally the honeycomb carrier was roasted in an air atmosphere at 500°C for 5 hours to obtain a honeycomb-type precious metal catalyst. The honeycomb-type precious metal catalyst manufactured as described above was aged at 1000°C for 4 hours, and then honeycomb-type precious metal catalyst samples with a diameter of 0.5 to 1 cm were cut out. Subsequently, catalytic performance tests were performed on the cut honeycomb-type precious metal catalyst samples. A simulated automobile exhaust gas mixture was used for the catalyst tests, and the content (volume ratio) of each component was 1.5% CO, 900 ppm NO, 900 ppm HC, 1.2% O2, 12% CO2, and the remainder N2. The space velocity was 50000 / h. The ignition temperature (T50) of the samples for catalytic conversion of CO, NO, and HC was tested, and the results showed that the ignition temperature of CO was 314°C, the ignition temperature of NO was 329°C, and the ignition temperature of HC was 311°C.

[0043] (Comparative Example 3) A fixed volume of palladium nitrate and rhodium nitrate solution with 1.2% palladium and 0.2% rhodium loadings is measured out, and 200g of Ce is added. 0.16 Zr 0.78 La 0.02 Nd 0.04 The sample was homogeneously mixed with O2 powder, dried at 110°C for 4 hours, and then roasted in an air atmosphere at 500°C for 5 hours to obtain a cerium zirconium-supported precious metal catalyst sample. Catalyst performance tests were performed on the sample, with the same sample preparation steps and catalyst test conditions as in Comparative Example 1. The test results showed that the ignition temperature of CO was 330°C, NO was 323°C, and HC was 331°C.

[0044] (Comparative Example 4) 200g Ce 0.16 Zr 0.78 La 0.02 Nd 0.04A slurry was prepared from O2 powder, 200 g of activated alumina, and an appropriate amount of deionized water. Palladium nitrate and rhodium nitrate were added in amounts of 0.6% palladium and 0.1% rhodium relative to the total mass of the honeycomb carrier activated coating, and mixed uniformly. An adhesive and acidity adjuster were then added to prepare a coating slurry. The slurry, prepared with a total loading amount of honeycomb catalyst noble metal of 1.4 g / L, was applied to a ceramic honeycomb carrier. The coated honeycomb carrier was dried at 110°C for 4 hours, and finally the honeycomb carrier was roasted in an air atmosphere at 500°C for 5 hours to obtain a honeycomb-type noble metal catalyst. Catalyst performance tests were performed on the samples. The sample manufacturing steps and catalyst test conditions were the same as in Comparative Example 2. The test results showed that the ignition temperature of CO was 326°C, the ignition temperature of NO was 319°C, and the ignition temperature of HC was 327°C.

[0045] (Example 1) A fixed volume of palladium nitrate and platinum nitrate solution with a loading of 0.9% palladium and 0.3% platinum is measured out, and 200g Ce 0.52 Zr 0.36 La 0.05 Y 0.07 The sample was uniformly mixed with O2 powder, dried at 110°C for 4 hours, then heat-treated at 550°C for 4 hours, and finally reduced-roasted under a hydrogen atmosphere at 500°C for 5 hours to obtain a catalyst sample PdPt / Ce with noble metals Pd and Pt supported on the grain boundaries and surface of the cerium zirconium composite oxide. 0.52 Zr 0.36 La 0.05 Y 0.07 O2 was obtained. Catalyst performance tests were performed on the samples. The sample manufacturing steps and catalyst test conditions were the same as in Comparative Example 1. The test results showed that the ignition temperature of CO was 290°C, the ignition temperature of NO was 320°C, and the ignition temperature of HC was 295°C.

[0046] (Example 2) Cerium zirconium composite oxide-supported precious metal catalyst PdPt / Ce prepared according to Example 1 0.52 Zr 0.36 La 0.05 Y 0.072200 g of O₂, an appropriate amount of alumina, and a certain amount of adhesive, acidity regulator, deionized water, etc. are used to form a coating slurry. The slurry prepared with a coating amount that gives a total supported amount of precious metal of 1.2 g / L in the honeycomb catalyst is coated onto a ceramic honeycomb carrier, then the coated honeycomb carrier is dried at 110°C for 4 hours, the honeycomb carrier is further heat-treated at 300°C for 5 hours, and finally the honeycomb carrier is calcined at 500°C for 5 hours to obtain a honeycomb-type precious metal catalyst, wherein the precious metals Pd and Pt are supported on the grain boundaries and surfaces of the cerium-zirconium composite oxide and alumina of the honeycomb-type precious metal catalyst. A catalyst performance test is carried out on the sample, the sample preparation steps and catalyst test conditions are the same as those of Comparative Example 2. The test results show that the light-off temperature of CO is 270°C, the light-off temperature of NO is 300°C, and the light-off temperature of HC is 284°C.

[0047] (Example 3) A certain volume of palladium nitrate and rhodium nitrate solution is weighed out according to the supported amounts of 1.2% palladium and 0.2% rhodium, and added to 200 g of Ce 0.16 Zr 0.78 La 0.02 Nd 0.04 O₂ powder and uniformly mixed, then the sample is dried at 110°C for 4 hours, the sample is further heat-treated at 550°C for 4 hours, and finally the sample is reduction-calcined at 500°C for 5 hours under a hydrogen atmosphere, to obtain a catalyst sample PdRh / Ce 0.16 Zr 0.78 La 0.02 Nd 0.04 O₂, wherein precious metals Pd and Rh are supported on the grain boundaries and surface of the cerium-zirconium composite oxide. A catalyst performance test is carried out on the sample, the sample preparation steps and catalyst test conditions are the same as those of Comparative Example 1. The test results show that the light-off temperature of CO is 278°C, the light-off temperature of NO is 279°C, and the light-off temperature of HC is 313°C.

[0048] (Example 4) The cerium-zirconium composite oxide supported precious metal catalyst PdRh / Ce 0.16 Zr 0.78 La 0.02 Nd 0.042200 g of O₂, an appropriate amount of activated alumina, a certain amount of adhesive, acidity regulator, deionized water, etc. are used to form a coating slurry. The slurry prepared at a coating amount of 1.4 g / L of the total supported amount of precious metal in the honeycomb catalyst is coated onto a ceramic honeycomb carrier, the coated honeycomb carrier is dried at 110°C for 4 hours, the honeycomb carrier is further heat-treated at 300°C for 5 hours, and finally the honeycomb carrier is calcined at 500°C for 5 hours to obtain a honeycomb-type precious metal catalyst, wherein the precious metals Pd and Rh are supported on the grain boundaries and surfaces of the cerium-zirconium composite oxide and alumina of the honeycomb-type precious metal catalyst. A catalyst performance test is carried out on the sample, the sample preparation steps and catalyst test conditions are the same as those of Comparative Example 2. The test results show that the ignition temperature of CO is 261°C, the ignition temperature of NO is 250°C, and the ignition temperature of HC is 287°C.

[0049] (Example 5) A certain volume of palladium nitrate solution, platinum nitrate solution and rhodium nitrate solution is weighed out according to the supported amounts of 0.4% palladium, 0.3% platinum and 0.01% rhodium, and added to 200 g of Ce 0.38 Zr 0.53 La 0.071 Pr 0.01 Y 0.01 O₂ powder and uniformly mixed, then the sample is dried at 110°C for 4 hours, the sample is further heat-treated at 550°C for 4 hours, and finally the sample is reduced and calcined at 500°C for 4 hours in a hydrogen atmosphere, to obtain a catalyst sample PdPtRh / Ce 0.38 Zr 0.53 La 0.071 Pr 0.01 Y 0.01 O₂ with precious metals Pd, Pt and Rh supported on the grain boundaries and surfaces of the cerium-zirconium composite oxide. A catalyst performance test is carried out on the sample, the sample preparation steps and catalyst test conditions are the same as those of Comparative Example 1. The test results show that the ignition temperature of CO is 260°C, the ignition temperature of NO is 287°C, and the ignition temperature of HC is 286°C.

[0050] (Example 6) A certain volume of palladium nitrate solution, platinum nitrate solution and rhodium nitrate solution is weighed out according to the supported amounts of 0.7% palladium, 0.2% platinum and 0.1% rhodium, and added to 200 g of Ce 0.33 Zr0.58 La 0.033 Nd 0.032 Y 0.025 The sample was uniformly mixed with O2 powder, dried at 110°C for 4 hours, then heat-treated at 200°C for 4 hours, and finally reduced-roasted under a hydrogen atmosphere at 500°C for 4 hours to obtain a catalyst sample PdPtRh / Cerium Zirconium composite oxide with noble metals Pd, Pt, and Rh supported on the grain boundaries and surface. 0.33 Zr 0.58 La 0.033 Nd 0.032 Y 0.025 O2 was obtained. Catalyst performance tests were performed on the samples. The sample manufacturing steps and catalyst test conditions were the same as in Comparative Example 1. The test results showed that the ignition temperature of CO was 315°C, the ignition temperature of NO was 324°C, and the ignition temperature of HC was 327°C.

[0051] (Example 7) A fixed volume of palladium nitrate, platinum nitrate, and rhodium nitrate solution with supported concentrations of 0.7% palladium, 0.2% platinum, and 0.1% rhodium is weighed out, and 200g of Ce is added. 0.33 Zr 0.58 La 0.033 Nd 0.032 Y 0.025 The sample was uniformly mixed with O2 powder, dried at 110°C for 4 hours, then heat-treated at 400°C for 4 hours, and finally reductively roasted at 500°C for 4 hours under a hydrogen atmosphere to obtain a catalyst sample PdPtRh / Cerium Zirconium composite oxide with noble metals Pd, Pt, and Rh supported on the grain boundaries and surface. 0.33 Zr 0.58 La 0.033 Nd 0.032 Y 0.025 O2 was obtained. Catalyst performance tests were performed on the samples. The sample manufacturing steps and catalyst test conditions were the same as in Comparative Example 1. The test results showed that the ignition temperature of CO was 278°C, the ignition temperature of NO was 310°C, and the ignition temperature of HC was 290°C.

[0052] (Example 8) A fixed volume of palladium nitrate, platinum nitrate, and rhodium nitrate solution with supported concentrations of 0.7% palladium, 0.2% platinum, and 0.1% rhodium is weighed out, and 200g of Ce is added. 0.33 Zr 0.58 La 0.033 Nd 0.032 Y 0.025 The sample was uniformly mixed with O2 powder, dried at 110°C for 4 hours, then heat-treated at 600°C for 4 hours, and finally reductively roasted at 500°C for 4 hours in a hydrogen atmosphere to obtain a catalyst sample PdPtRh / Cerium Zirconium composite oxide with noble metals Pd, Pt, and Rh supported on the grain boundaries and surface. 0.33 Zr 0.58 La 0.033 Nd 0.032 Y 0.025 O2 was obtained. Catalyst performance tests were performed on the samples. The sample manufacturing steps and catalyst test conditions were the same as in Comparative Example 1. The test results showed that the ignition temperature of CO was 259°C, the ignition temperature of NO was 277°C, and the ignition temperature of HC was 278°C.

[0053] (Example 9) Cerium zirconium composite oxide-supported precious metal catalyst PdPtRh / Ce prepared according to Example 8 0.33 Zr 0.58 La 0.033 Nd 0.032 Y 0.025 A coating slurry was prepared by combining 200g of O2, an appropriate amount of activated alumina, a certain amount of adhesive, an acidity adjuster, and deionized water. This slurry was then applied to a ceramic honeycomb support at a coating rate of 1g / L for the total amount of honeycomb catalyst noble metal supported. The coated honeycomb support was dried at 110°C for 4 hours, then heat-treated at 400°C for 12 hours, and finally roasted at 500°C for 5 hours to obtain a honeycomb-type noble metal catalyst. The noble metals Pd, Pt, and Rh were supported on the grain boundaries and surface of the cerium zirconium composite oxide and alumina of the honeycomb-type noble metal catalyst. Catalyst performance tests were performed on the samples. The sample manufacturing steps and catalyst test conditions were the same as in Comparative Example 2. The test results showed that the ignition temperature of CO was 257°C, the ignition temperature of NO was 283°C, and the ignition temperature of HC was 267°C.

[0054] (Example 10) A fixed volume of palladium, platinum, and rhodium chloride liquid salts with supported concentrations of 0.7% palladium, 0.2% platinum, and 0.1% rhodium is weighed out, and 200g of Ce is added. 0.33 Zr 0.58 La 0.033 Nd 0.032 Y 0.025 The sample was uniformly mixed with O2 powder, dried at 110°C for 4 hours, then subjected to a first heat treatment at 450°C for 4 hours, followed by a second heat treatment at 800°C for 4 hours, and finally reduced-roasted in a hydrogen atmosphere at 500°C for 4 hours to obtain a catalyst sample PdPtRh / Cerium Zirconium composite oxide with noble metals Pd, Pt, and Rh supported on the grain boundaries and surface. 0.33 Zr 0.58 La 0.033 Nd 0.032 Y 0.025 O2 was obtained. Catalyst performance tests were performed on the samples. The sample manufacturing steps and catalyst test conditions were the same as in Comparative Example 1. The test results showed that the ignition temperature of CO was 264°C, the ignition temperature of NO was 291°C, and the ignition temperature of HC was 275°C.

[0055] (Example 11) A coating slurry was prepared by combining 200g of activated alumina with a certain amount of adhesive, acidity adjuster, and deionized water. The alumina slurry was then applied to a ceramic honeycomb support in an amount containing 100g / L of alumina, and the coated honeycomb support was dried at 110°C for 4 hours. The cerium zirconium composite oxide-supported precious metal catalyst PdPtRh / Ce produced according to Example 10 was then prepared. 0.33 Zr 0.58 La 0.033 Nd 0.032 Y 0.025A slurry was prepared by coating 200g of O2 with a certain amount of adhesive, acidity adjuster, and deionized water. This slurry was prepared with a total loading amount of honeycomb catalyst noble metal of 1g / L and coated onto the alumina-coated ceramic honeycomb support. The coated honeycomb support was dried at 110°C for 4 hours, then heat-treated at 600°C for 4 hours, and finally roasted at 500°C for 5 hours to obtain a honeycomb-type noble metal catalyst. The noble metals Pd, Pt, and Rh were mainly supported at the grain boundaries and surface of the cerium zirconium composite oxide of the honeycomb-type noble metal catalyst, with small amounts supported at the grain boundaries and surface of the cerium zirconium composite oxide and alumina. Catalyst performance tests were performed on the samples. The sample manufacturing steps and catalyst test conditions were the same as in Comparative Example 2. The test results showed that the ignition temperature of CO was 267°C, the ignition temperature of NO was 279°C, and the ignition temperature of HC was 274°C.

[0056] (Example 12) A fixed volume of palladium-rhodium liquid acetate with a loading of 0.8% palladium and 0.08% rhodium is weighed out, and the surface of the cerium zirconium composite oxide Ce has a core-shell structure rich in yttrium. 0.18 Zr 0.64 La 0.03 Y 0.15 The sample was uniformly mixed with 200g of O2 powder, dried at 110°C for 4 hours, then subjected to a first heat treatment at 600°C for 6 hours, followed by a second heat treatment at 580°C for 5 hours, resulting in a catalyst sample PdRh / Cerium zirconium composite oxide with noble metals Pd and Rh supported on the grain boundaries and surface. 0.18 Zr 0.64 La 0.03 Y 0.15 O2 was obtained. Catalyst performance tests were performed on the samples. The sample manufacturing steps and catalyst test conditions were the same as in Comparative Example 1. The test results showed that the ignition temperature of CO was 251°C, the ignition temperature of NO was 264°C, and the ignition temperature of HC was 239°C.

[0057] (Example 13) Grain boundaries and surface-supported noble metal catalyst PdRh / Ce of cerium zirconium composite oxide prepared according to Example 12 0.18 Zr0.64 La 0.03 Y 0.15 A coating slurry was prepared by combining 200g of O2, an appropriate amount of activated alumina, a certain amount of adhesive, an acidity adjuster, and deionized water. This slurry was then applied to a ceramic honeycomb support with a total loading amount of 0.88g / L of honeycomb catalyst noble metal. The coated honeycomb support was dried at 110°C for 4 hours, then heat-treated at 600°C for 6 hours, and finally roasted at 580°C for 5 hours to obtain a honeycomb-type noble metal catalyst. The noble metals Pd and Rh were supported on the grain boundaries and surface of the cerium zirconium composite oxide and alumina of the honeycomb-type noble metal catalyst. Catalyst performance tests were performed on the samples. The sample manufacturing steps and catalyst test conditions were the same as in Comparative Example 2. The test results showed that the ignition temperature of CO was 243°C, the ignition temperature of NO was 250°C, and the ignition temperature of HC was 235°C.

[0058] (Example 14) A fixed volume of platinum-rhodium liquid acetate is weighed out with a platinum-0.3% and rhodium-0.02% loading, and a cerium-rich gradient cerium zirconium composite oxide (Ce) is placed on the surface. 0.33 Zr 0.57 La 0.04 Y 0.06 The sample was uniformly mixed with 200g of O2 powder, dried at 110°C for 4 hours, then subjected to a first heat treatment at 550°C for 4 hours, followed by a second heat treatment at 500°C for 5 hours to obtain a catalyst sample PtRh / Ce with noble metals Pt and Rh supported on the grain boundaries and surface of the cerium zirconium composite oxide. 0.33 Zr 0.57 La 0.04 Y 0.06 O2 was obtained. Catalyst performance tests were performed on the samples. The sample manufacturing steps and catalyst test conditions were the same as in Comparative Example 1. The test results showed that the ignition temperature of CO was 241°C, the ignition temperature of NO was 246°C, and the ignition temperature of HC was 251°C.

[0059] (Example 15) Cerium zirconium composite oxide-supported precious metal catalyst PtRh / Ce prepared according to Example 14 0.33 Zr 0.57 La0.04 Y 0.06 A coating slurry was prepared by combining 200g of O2, an appropriate amount of activated alumina, a certain amount of adhesive, an acidity adjuster, and deionized water. This slurry was then applied to a ceramic honeycomb support with a total loading amount of 0.32g / L of honeycomb catalyst noble metal. The coated honeycomb support was dried at 110°C for 4 hours, then heat-treated at 550°C for 4 hours, and finally roasted at 500°C for 5 hours to obtain a honeycomb-type noble metal catalyst. The noble metals Pt and Rh were supported on the grain boundaries and surface of the cerium zirconium composite oxide and alumina of the honeycomb-type noble metal catalyst. Catalyst performance tests were performed on the samples. The sample manufacturing steps and catalyst test conditions were the same as in Comparative Example 2. The test results showed that the ignition temperature of CO was 235°C, the ignition temperature of NO was 230°C, and the ignition temperature of HC was 243°C.

[0060] (Example 16) A fixed volume of palladium-platinum liquid nitrate with a loading of 0.2% palladium and 0.5% platinum is weighed out, and the surface of the cerium zirconium composite oxide Ce has a core-shell structure rich in cerium yttrium. 0.42 Zr 0.47 La 0.045 Y 0.064 The sample was uniformly mixed with 200g of O2 powder, dried at 110°C for 4 hours, then subjected to a first heat treatment at 610°C for 7 hours, followed by a second heat treatment at 470°C for 4 hours to obtain a catalyst sample PdPt / Cerium Zirconium composite oxide with noble metals Pd and Pt supported on the grain boundaries and surface. 0.42 Zr 0.47 La 0.045 Y 0.064 O2 was obtained. Catalyst performance tests were performed on the samples. The sample manufacturing steps and catalyst test conditions were the same as in Comparative Example 1. The test results showed that the ignition temperature of CO was 243°C, the ignition temperature of NO was 259°C, and the ignition temperature of HC was 239°C.

[0061] (Example 17) Cerium zirconium composite oxide-supported precious metal catalyst PdPt / Ce prepared according to Example 16 0.42 Zr 0.47 La0.045 Y 0.064 A coating slurry was prepared by combining 200g of O2, an appropriate amount of activated alumina, a certain amount of adhesive, an acidity adjuster, and deionized water. This slurry was then applied to a ceramic honeycomb support with a total loading amount of 0.7g / L of honeycomb catalyst noble metal. The coated honeycomb support was dried at 110°C for 4 hours, then heat-treated at 490°C for 7 hours, and finally roasted at 570°C for 4 hours to obtain a honeycomb-type noble metal catalyst. The noble metals Pd and Pt were supported on the grain boundaries and surface of the cerium zirconium composite oxide and alumina of the honeycomb-type noble metal catalyst. Catalyst performance tests were performed on the samples. The sample manufacturing steps and catalyst test conditions were the same as in Comparative Example 2. The test results showed that the ignition temperature of CO was 237°C, the ignition temperature of NO was 248°C, and the ignition temperature of HC was 227°C.

[0062] (Example 18) A fixed volume of palladium-rhodium liquid nitrate with a loading of 0.1% palladium and 0.02% rhodium is weighed out, and the surface of the cerium zirconium composite oxide Ce has a core-shell structure rich in neodymium. 0.24 Zr 0.7 La 0.017 Nd 0.043 The sample was uniformly mixed with 200g of O2 powder, dried at 110°C for 4 hours, then subjected to a first heat treatment at 520°C for 3 hours, followed by a second heat treatment at 630°C for 6 hours, resulting in a catalyst sample PdRh / Ce with noble metals Pd and Rh supported on the grain boundaries and surface of the cerium zirconium composite oxide. 0.24 Zr 0.7 La 0.017 Nd 0.043 O2 was obtained. Catalyst performance tests were performed on the samples. The sample manufacturing steps and catalyst test conditions were the same as in Comparative Example 1. The test results showed that the ignition temperature of CO was 233°C, the ignition temperature of NO was 211°C, and the ignition temperature of HC was 225°C.

[0063] (Example 19) Cerium zirconium composite oxide-supported precious metal catalyst PdRh / Ce prepared according to Example 18 0.24 Zr 0.7 La0.017 Nd 0.043 A coating slurry was prepared by combining 200g of O2, an appropriate amount of activated alumina, a certain amount of adhesive, an acidity adjuster, and deionized water. This slurry was then applied to a ceramic honeycomb support with a total loading amount of honeycomb catalyst noble metal of 0.12g / L. The coated honeycomb support was dried at 110°C for 4 hours, then heat-treated at 510°C for 3 hours, and finally roasted at 600°C for 5 hours to obtain a honeycomb-type noble metal catalyst. The noble metals Pd and Rh were supported on the grain boundaries and surface of the cerium zirconium composite oxide and alumina of the honeycomb-type noble metal catalyst. Catalyst performance tests were performed on the samples. The sample manufacturing steps and catalyst test conditions were the same as in Comparative Example 2. The test results showed that the ignition temperature of CO was 230°C, the ignition temperature of NO was 205°C, and the ignition temperature of HC was 222°C.

[0064] (Example 20) A fixed volume of palladium nitrate and platinum nitrate solution with a loading of 1% palladium and 0.01% platinum was uniformly mixed with 200 g of CeO2 powder. The sample was then dried at 110°C for 4 hours, followed by heat treatment at 500°C for 4.5 hours. Finally, the sample was reduced-roasted under a hydrogen atmosphere at 400°C for 24 hours to obtain a catalyst sample PdPt / CeO2 in which the noble metals Pd and Pt were supported at the grain boundaries and on the surface of cerium oxide. Catalyst performance tests were performed on the sample, with the same sample manufacturing steps and catalyst test conditions as in Comparative Example 1. The test results showed that the ignition temperature for CO was 304°C, for NO 339°C, and for HC 317°C.

[0065] (Example 21) A coating slurry was prepared by coating 200 g of cerium oxide-supported precious metal catalyst PdPt / CeO2, an appropriate amount of activated alumina, a certain amount of adhesive, an acidity adjuster, and deionized water, according to Example 20. The slurry was then coated onto a ceramic honeycomb support with a total loading amount of honeycomb catalyst precious metal of 0.61 g / L. The coated honeycomb support was dried at 110°C for 4 hours, then heat-treated at 300°C for 18 hours, and finally roasted at 400°C for 12 hours to obtain a honeycomb-type precious metal catalyst. The precious metals Pd and Pt were supported on the grain boundaries and surface of the cerium oxide and alumina in the honeycomb-type precious metal catalyst. Catalyst performance tests were performed on the samples. The sample manufacturing steps and catalyst test conditions were the same as in Comparative Example 2. The test results showed that the ignition temperature of CO was 288°C, the ignition temperature of NO was 329°C, and the ignition temperature of HC was 303°C.

[0066] (Example 22) A fixed volume of palladium and rhodium acetate solution with a loading of 1.2% palladium and 0.08% rhodium is mixed with 200g of Ce 0.38 Zr 0.53 La 0.045 Sm 0.03 Tm 0.015 The sample was uniformly mixed with O2 powder, dried at 110°C for 4 hours, heat-treated at 600°C for 4 hours, subjected to a first reductive roasting at 500°C for 5 hours under a hydrogen atmosphere, and finally subjected to a second reductive roasting at 650°C for 2 hours under a hydrogen atmosphere to obtain a catalyst sample PdRh / Ce with noble metals Pd and Rh supported on the grain boundaries and surface of the cerium zirconium composite oxide. 0.38 Zr 0.53 La 0.045 Sm 0.03 Tm 0.015 O2 was obtained. Catalyst performance tests were performed on the samples. The sample manufacturing steps and catalyst test conditions were the same as in Comparative Example 1. The test results showed that the ignition temperature of CO was 254°C, the ignition temperature of NO was 257°C, and the ignition temperature of HC was 260°C.

[0067] (Example 23) A fixed volume of platinum nitrate and rhodium nitrate solution with a platinum load of 1.9% and rhodium load of 0.1% is mixed with 200g of Ce 0.13 Zr 0.64 La 0.03 Nd 0.03 Mn 0.17 The sample was uniformly mixed with O2 powder, dried at 110°C for 4 hours, then heat-treated at 200°C for 24 hours, and finally reduced-roasted in a CO atmosphere at 700°C for 0.5 hours to obtain a catalyst sample PtRh / Ce with noble metals Pt and Rh supported on the grain boundaries and surface of the cerium zirconium composite oxide. 0.13 Zr 0.64 La 0.03 Nd 0.03 Mn 0.17 O2 was obtained. Catalyst performance tests were performed on the samples. The sample manufacturing steps and catalyst test conditions were the same as in Comparative Example 1. The test results showed that the ignition temperature of CO was 286°C, the ignition temperature of NO was 280°C, and the ignition temperature of HC was 293°C.

[0068] (Example 24) Cerium zirconium composite oxide-supported precious metal catalyst PdRh / Ce prepared according to Example 23 0.38 Zr 0.53 La 0.045 Sm 0.03 Tm 0.015 A coating slurry a was prepared by combining 200g of O2, an appropriate amount of activated alumina, a certain amount of adhesive, an acidity adjuster, and deionized water, and a cerium zirconium composite oxide-supported precious metal catalyst PtRh / Ce was prepared according to Example 15. 0.13 Zr 0.64 La 0.03 Nd 0.03 Mn 0.17Another coating slurry b was prepared by combining 200g of O2, an appropriate amount of activated alumina, a certain amount of adhesive, an acidity adjuster, and deionized water. Slurry a was then applied to half of the honeycomb support at a coating rate of 0.64 g / L of precious metal, and the half coated honeycomb support was dried at 110°C for 4 hours. Slurry b was then applied to the remaining half of the honeycomb support at a coating rate of 1 g / L of precious metal, and the coated honeycomb support was dried at 110°C for 4 hours. Next, the honeycomb support was heat-treated at 450°C for 3 hours, and finally, the honeycomb support was roasted at 550°C for 6 hours to obtain a honeycomb-type precious metal catalyst with a total precious metal load of 1.64 g / L. The precious metals Pd, Pt, and Rh were supported on the grain boundaries and surface of the cerium zirconium composite oxide and alumina of the honeycomb-type precious metal catalyst. Catalyst performance tests were performed on the samples. The sample manufacturing steps and catalyst test conditions were the same as in Comparative Example 2. The test results showed that the ignition temperature of CO was 245°C, the ignition temperature of NO was 249°C, and the ignition temperature of HC was 247°C.

[0069] (Example 25) A constant volume of rhodium nitrate solution with a 0.01% rhodium load is mixed with 200g of Ce 0.78 Zr 0.16 La 0.02 Y 0.02 Fe 0.02 The sample was uniformly mixed with O2 powder, dried at 110°C for 4 hours, then heat-treated at 300°C for 20 hours, roasted at 450°C in an air atmosphere for 4 hours, and finally reductively roasted at 570°C in a hydrogen atmosphere for 5 hours to produce a catalyst sample Rh / Ce with rhodium supported on the grain boundaries and surface of the cerium zirconium composite oxide. 0.78 Zr 0.16 La 0.02 Y 0.02 Fe 0.02 O2 was obtained. Catalyst performance tests were performed on the samples. The sample manufacturing steps and catalyst test conditions were the same as in Comparative Example 1. The test results showed that the ignition temperature of CO was 313°C, the ignition temperature of NO was 291°C, and the ignition temperature of HC was 305°C.

[0070] (Example 26) Cerium zirconium composite oxide-supported noble metal catalyst Rh / Ce prepared according to Example 25 0.78 Zr 0.16 La 0.02 Y 0.02 Fe 0.02 A coating slurry was prepared by combining 200g of O2, an appropriate amount of activated alumina, a certain amount of adhesive, an acidity adjuster, and deionized water. This slurry was then applied to a ceramic honeycomb support with a total loading amount of 0.01g / L of honeycomb catalyst noble metal. The coated honeycomb support was dried at 110°C for 4 hours, and finally roasted at 500°C for 5 hours to obtain a honeycomb-type noble metal catalyst. The noble metal Rh was supported on the grain boundaries and surface of the cerium zirconium composite oxide and alumina of the honeycomb-type noble metal catalyst. Catalyst performance tests were performed on the samples. The sample manufacturing steps and catalyst test conditions were the same as in Comparative Example 2. The test results showed that the ignition temperature of CO was 296°C, the ignition temperature of NO was 281°C, and the ignition temperature of HC was 293°C.

[0071] (Example 27) A fixed volume of palladium nitrate solution with a 0.5% palladium load is measured out, and 200g of Ce is added. 0.38 Zr 0.5 La 0.07 Pr 0.03 Y 0.01 Si 0.01 O 1.999 N 0.001 The sample was then uniformly mixed with 200g of activated alumina powder, dried at 110°C for 4 hours, heat-treated at 550°C for 3 hours, and finally reduced-roasted under a hydrogen atmosphere at 470°C for 16 hours to produce a catalyst sample Pd / Ce with noble metal Pd supported on the grain boundaries and surface of cerium zirconium composite oxide and alumina. 0.38 Zr 0.5 La 0.07 Pr 0.03 Y 0.01 Si 0.01 O 1.999 N 0.001Al2O3 was obtained. Catalyst performance tests were performed on the sample. The sample manufacturing steps and catalyst test conditions were the same as in Comparative Example 1. The test results showed that the ignition temperature of CO was 265°C, the ignition temperature of NO was 270°C, and the ignition temperature of HC was 270°C.

[0072] (Example 28) Cerium zirconium composite oxide and alumina-supported precious metal catalyst Pd / Ce prepared according to Example 27 0.38 Zr 0.5 La 0.07 Pr 0.03 Y 0.01 Si 0.01 O 1.999 N 0.001 A slurry was prepared by coating 200g of Al2O3 with an appropriate amount of adhesive, acidity adjuster, and deionized water. This slurry was then applied to a ceramic honeycomb support with a total loading amount of honeycomb catalyst noble metal of 1g / L. The coated honeycomb support was dried at 110°C for 4 hours, then heat-treated at 750°C for 1 hour, and finally roasted at 600°C for 5 hours to obtain a honeycomb-type noble metal catalyst. The noble metal Pd was supported on the grain boundaries and surface of the cerium zirconium composite oxide and alumina of the honeycomb-type noble metal catalyst. Catalyst performance tests were performed on the samples. The sample manufacturing steps and catalyst test conditions were the same as in Comparative Example 2. The test results showed that the ignition temperature of CO was 260°C, the ignition temperature of NO was 263°C, and the ignition temperature of HC was 258°C.

[0073] (Example 29) A fixed volume of palladium nitrate and platinum nitrate solution with a loading of 0.5% palladium and 1.8% platinum is mixed with 200g of Ce 0.18 Zr 0.64 La 0.03 Y 0.13 Yb 0.02 O 1.995 F 0.005 The sample was uniformly mixed with the powder, dried at 110°C for 4 hours, then heat-treated at 600°C for 4 hours, and finally reductively roasted at 600°C for 4 hours in a hydrogen atmosphere to obtain a catalyst sample PdPt / Cerium Zirconium composite oxide with noble metals Pd and Pt supported on the grain boundaries and surface.0.18 Zr 0.64 La 0.03 Y 0.13 Yb 0.02 O 1.995 F 0.005 The following results were obtained. Catalyst performance tests were performed on the samples, with the same sample manufacturing steps and catalyst test conditions as in Comparative Example 1. The test results showed that the ignition temperature of CO was 243°C, the ignition temperature of NO was 261°C, and the ignition temperature of HC was 242°C.

[0074] (Example 30) A fixed volume of platinum nitrate and rhodium nitrate solution with platinum 0.9% and rhodium 0.01% loadings is mixed with 200g of Ce 0.33 Zr 0.5 La 0.033 Nd 0.032 Y 0.025 Sr 0.04 Ba 0.04 The sample was uniformly mixed with O2 powder, dried at 110°C for 4 hours, then heat-treated at 600°C for 6.5 hours, and finally reduced-roasted under a hydrogen atmosphere at 500°C for 12 hours to produce a catalyst sample PtRh / Ce with noble metals Pt and Rh supported on the grain boundaries and surface of the cerium zirconium composite oxide. 0.33 Zr 0.5 La 0.033 Nd 0.032 Y 0.025 Sr 0.04 Ba 0.04 O2 was obtained. Catalyst performance tests were performed on the samples. The sample manufacturing steps and catalyst test conditions were the same as in Comparative Example 1. The test results showed that the ignition temperature of CO was 256°C, the ignition temperature of NO was 261°C, and the ignition temperature of HC was 263°C.

[0075] (Example 31) A cerium zirconium composite oxide-supported precious metal catalyst PtRh / Ce was prepared according to Example 30, with a cerium zirconium content of 90% and an alumina content of 10% in a honeycomb-type precious metal catalyst coating. 0.33 Zr 0.5 La 0.033 Nd 0.032 Y 0.025 Sr 0.04 Ba 0.04A slurry was prepared by coating 200g of O2, an appropriate amount of activated alumina, a certain amount of adhesive, an acidity adjuster, and deionized water. The slurry was prepared with a total loading amount of honeycomb catalyst noble metal of 1.64g / L and coated onto a ceramic honeycomb support. The coated honeycomb support was dried at 110°C for 4 hours, then heat-treated at 800°C for 0.5 hours, and finally roasted at 700°C for 0.5 hours to obtain a honeycomb-type noble metal catalyst. The noble metals Pt and Rh were supported on the grain boundaries and surface of the cerium zirconium composite oxide and alumina of the honeycomb-type noble metal catalyst. Catalyst performance tests were performed on the samples. The sample manufacturing steps and catalyst test conditions were the same as in Comparative Example 2. The test results showed that the ignition temperature of CO was 265°C, the ignition temperature of NO was 271°C, and the ignition temperature of HC was 274°C.

[0076] (Example 32) A fixed volume of platinum nitrate and rhodium nitrate solution with a platinum load of 0.5% and rhodium load of 0.4% is mixed with 200g of Ce 0.16 Zr 0.6 La 0.02 Nd 0.04 Mn 0.12 Ba 0.06 The sample was uniformly mixed with O2 powder, dried at 110°C for 4 hours, then heat-treated at 700°C for 8 hours, and finally reduced-roasted under a hydrogen atmosphere at 600°C for 4 hours to obtain a catalyst sample PtRh / Ce with noble metals Pt and Rh supported on the grain boundaries and surface of the cerium zirconium composite oxide. 0.16 Zr 0.6 La 0.02 Nd 0.04 Mn 0.12 Ba 0.06 O2 was obtained. Catalyst performance tests were performed on the samples. The sample manufacturing steps and catalyst test conditions were the same as in Comparative Example 1. The test results showed that the ignition temperature of CO was 251°C, the ignition temperature of NO was 248°C, and the ignition temperature of HC was 260°C.

[0077] (Example 33) Cerium zirconium composite oxide-supported precious metal catalyst PtRh / Ce prepared according to Example 32 0.16 Zr 0.6 La0.02 Nd 0.04 Mn 0.12 Ba 0.06 A coating slurry was prepared by combining 200g of O2, an appropriate amount of activated alumina, a certain amount of adhesive, an acidity adjuster, and deionized water. This slurry was then applied to a ceramic honeycomb support with a total loading amount of honeycomb catalyst noble metal of 1.08g / L. The coated honeycomb support was dried at 110°C for 4 hours, then heat-treated at 430°C for 3 hours, and finally roasted at 650°C for 6 hours to obtain a honeycomb-type noble metal catalyst. The noble metals Pt and Rh were supported on the grain boundaries and surface of the cerium zirconium composite oxide and alumina of the honeycomb-type noble metal catalyst. Catalyst performance tests were performed on the samples. The sample manufacturing steps and catalyst test conditions were the same as in Comparative Example 2. The test results showed that the ignition temperature of CO was 247°C, the ignition temperature of NO was 242°C, and the ignition temperature of HC was 253°C.

[0078] (Example 34) A constant volume of rhodium nitrate solution with a 0.1% rhodium load is added to 200g of Zr 0.86 La 0.09 Y 0.04 Ti 0.01 The sample was uniformly mixed with O2 powder, dried at 110°C for 4 hours, then heat-treated at 420°C for 6 hours, and finally reduced-roasted under a hydrogen atmosphere at 630°C for 4 hours to obtain a catalyst sample Rh / Zr with noble metal Rh supported on the grain boundaries and surface of the cerium zirconium composite oxide. 0.86 La 0.09 Y 0.04 Ti 0.01 O2 was obtained. Catalyst performance tests were performed on the samples. The sample manufacturing steps and catalyst test conditions were the same as in Comparative Example 1. The test results showed that the ignition temperature of CO was 271°C, the ignition temperature of NO was 248°C, and the ignition temperature of HC was 277°C.

[0079] (Example 35) A cerium zirconium composite oxide-supported precious metal catalyst Rh / Zr was prepared according to Example 34, with a cerium zirconium content of 70% and an alumina content of 30% in a honeycomb-type precious metal catalyst coating. 0.86 La0.09 Y 0.04 Ti 0.01 A coating slurry was prepared by combining 200g of O2, an appropriate amount of activated alumina, a certain amount of adhesive, an acidity adjuster, and deionized water. This slurry was then applied to a ceramic honeycomb support with a total loading amount of 0.14g / L of honeycomb catalyst noble metal. The coated honeycomb support was dried at 110°C for 4 hours, then heat-treated at 550°C for 3 hours, and finally roasted at 700°C for 1.5 hours to obtain a honeycomb-type noble metal catalyst. The noble metal rhodium was supported on the grain boundaries and surface of the cerium zirconium composite oxide and alumina of the honeycomb-type noble metal catalyst. Catalyst performance tests were performed on the samples. The sample manufacturing steps and catalyst test conditions were the same as in Comparative Example 2. The test results showed that the ignition temperature of CO was 268°C, the ignition temperature of NO was 233°C, and the ignition temperature of HC was 272°C.

[0080] (Example 36) A constant volume of rhodium nitrate solution with a 0.1% rhodium load is added to 200g of Zr 0.86 La 0.095 Y 0.045 The sample was uniformly mixed with O2 powder, dried at 110°C for 4 hours, then heat-treated at 630°C for 5 hours, and finally reduced-roasted under a hydrogen atmosphere at 700°C for 5 hours to obtain a catalyst sample Rh / Zr with noble metal Rh supported on the grain boundaries and surface of the cerium zirconium composite oxide. 0.86 La 0.095 Y 0.045 O2 was obtained. Catalyst performance tests were performed on the samples. The sample manufacturing steps and catalyst test conditions were the same as in Comparative Example 1. The test results showed that the ignition temperature of CO was 270°C, NO was 264°C, and HC was 274°C.

[0081] (Example 37) A cerium zirconium composite oxide-supported precious metal catalyst Rh / Zr was prepared according to Example 34, with a cerium zirconium content of 70% and an alumina content of 30% in a honeycomb-type precious metal catalyst coating. 0.86 La 0.095 Y 0.045A coating slurry was prepared by combining 200g of O2, an appropriate amount of activated alumina, a certain amount of adhesive, an acidity adjuster, and deionized water. This slurry was then applied to a ceramic honeycomb support with a total loading amount of 0.14g / L of honeycomb catalyst noble metal. The coated honeycomb support was dried at 110°C for 4 hours, then heat-treated at 600°C for 3 hours, and finally roasted at 660°C for 5 hours to obtain a honeycomb-type noble metal catalyst. The noble metal rhodium was supported on the grain boundaries and surface of the cerium zirconium composite oxide and alumina of the honeycomb-type noble metal catalyst. Catalyst performance tests were performed on the samples. The sample manufacturing steps and catalyst test conditions were the same as in Comparative Example 2. The test results showed that the ignition temperature of CO was 265°C, the ignition temperature of NO was 251°C, and the ignition temperature of HC was 268°C.

[0082] (Example 38) A fixed volume of palladium nitrate, platinum nitrate, and rhodium nitrate solutions with supported concentrations of 0.1% palladium, 0.2% platinum, and 0.1% rhodium is mixed with 200g of Ce. 0.25 Zr 0.6 La 0.05 Y 0.05 Nb 0.02 Sn 0.03 The sample was uniformly mixed with O2 powder, dried at 110°C for 4 hours, then heat-treated at 620°C for 4 hours, and finally reduced-roasted under a hydrogen atmosphere at 520°C for 7 hours to produce a catalyst sample PdPtRh / Ce with noble metals Pd, Pt, and Rh supported on the grain boundaries and surface of the cerium zirconium composite oxide. 0.25 Zr 0.6 La 0.05 Y 0.05 Nb 0.02 Sn 0.03 O2 was obtained. Catalyst performance tests were performed on the samples. The sample manufacturing steps and catalyst test conditions were the same as in Comparative Example 1. The test results showed that the ignition temperature of CO was 276°C, the ignition temperature of NO was 257°C, and the ignition temperature of HC was 273°C.

[0083] (Example 39) A constant volume of rhodium nitrate solution with a 0.1% rhodium load is mixed with 200g of Ce 0.18 Zr 0.62 La0.03 Y 0.13 Er 0.02 Ni 0.02 The sample was uniformly mixed with O2 powder, dried at 110°C for 4 hours, then heat-treated at 710°C for 2 hours, and finally reduced-roasted under a hydrogen atmosphere at 650°C for 3 hours to produce a catalyst sample Rh / Ce with noble metal Rh supported on the grain boundaries and surface of the cerium zirconium composite oxide. 0.18 Zr 0.62 La 0.03 Y 0.13 Er 0.02 Ni 0.02 O2 was obtained. Catalyst performance tests were performed on the samples. The sample manufacturing steps and catalyst test conditions were the same as in Comparative Example 1. The test results showed that the ignition temperature of CO was 291°C, the ignition temperature of NO was 258°C, and the ignition temperature of HC was 285°C.

[0084] (Example 40) A fixed volume of palladium nitrate and platinum nitrate solution with a loading of 0.9% palladium and 0.5% platinum is mixed with 200g of Al 0.48 Ce 0.175 Zr 0.3 La 0.018 Nd 0.018 Y 0.009 The sample was uniformly mixed with O2 powder, dried at 110°C for 4 hours, then heat-treated at 650°C for 5 hours, and finally reduced-roasted in a hydrogen atmosphere at 500°C for 5 hours to produce a catalyst sample PdPt / Al with noble metals Pd and Pt supported on the grain boundaries and surface of the cerium zirconium composite oxide. 0.48 Ce 0.175 Zr 0.3 La 0.018 Nd 0.018 Y 0.009 O2 was obtained. Catalyst performance tests were performed on the samples. The sample manufacturing steps and catalyst test conditions were the same as in Comparative Example 1. The test results showed that the ignition temperature of CO was 273°C, the ignition temperature of NO was 285°C, and the ignition temperature of HC was 277°C.

[0085] (Example 41) Cerium zirconium composite oxide-supported precious metal catalyst PdPt / Al prepared according to Example 40 0.48 Ce0.175 Zr 0.3 La 0.018 Nd 0.018 Y 0.009 A slurry was prepared by coating 200g of O2, an appropriate amount of activated alumina, a certain amount of adhesive, an acidity adjuster, and deionized water. The slurry was then coated onto a ceramic honeycomb support with a total loading amount of honeycomb catalyst noble metal of 1.4g / L. The coated honeycomb support was dried at 110°C for 4 hours, then heat-treated at 250°C for 4 hours, and finally roasted at 470°C for 16 hours to obtain a honeycomb-type noble metal catalyst. The noble metals Pd and Pt were supported on the grain boundaries and surface of the cerium zirconium composite oxide and alumina of the honeycomb-type noble metal catalyst. Catalyst performance tests were performed on the samples. The sample manufacturing steps and catalyst test conditions were the same as in Comparative Example 2. The test results showed that the ignition temperature of CO was 253°C, the ignition temperature of NO was 264°C, and the ignition temperature of HC was 269°C.

[0086] (Example 42) A fixed volume of palladium nitrate and platinum nitrate solution with a loading of 0.01% palladium and 2% platinum is mixed with 200g of Ce. 0.30 Zr 0.61 La 0.044 Gd 0.04 Cu 0.006 The sample was uniformly mixed with O2 powder, dried at 110°C for 4 hours, then heat-treated at 270°C for 12 hours, followed by a first roasting at 440°C for 3 hours under an air atmosphere, and finally a second roasting at 620°C for 3 hours under an air atmosphere to obtain a catalyst sample PdPt / Ce with noble metals Pd and Pt supported on the grain boundaries and surface of the cerium zirconium composite oxide. 0.30 Zr 0.61 La 0.044 Gd 0.04 Cu 0.006 O2 was obtained. Catalyst performance tests were performed on the samples. The sample manufacturing steps and catalyst test conditions were the same as in Comparative Example 1. The test results showed that the ignition temperature of CO was 283°C, the ignition temperature of NO was 272°C, and the ignition temperature of HC was 278°C.

[0087] (Example 43) A fixed volume of platinum nitrate solution with a platinum load of 0.5% was uniformly mixed with 200 g of activated alumina powder. The sample was then dried at 110°C for 4 hours, followed by heat treatment at 350°C for 7 hours. Finally, the sample was reduced and roasted at 500°C in a hydrogen atmosphere for 5 hours to obtain a catalyst sample Pt / Al2O3 in which the noble metal Pt was supported at the alumina grain boundaries and on the surface. 320g of Pt / Al2O3 and Ce were prepared using a mass ratio of 4:1 between Pt / Al2O3 and cerium zirconium powder. 0.13 Zr 0.64 La 0.03 Nd 0.03 Mn 0.17 A slurry was prepared by coating 280g of O, a certain amount of adhesive, an acidity adjuster, and deionized water. This slurry was then applied to a honeycomb support at a coating rate of 0.8g / L, with a total supported amount of honeycomb catalyst precious metal. The coated honeycomb support was dried at 110°C for 4 hours, then heat-treated at 270°C for 7 hours, and finally roasted at 500°C for 5 hours to obtain a honeycomb-type precious metal catalyst. The precious metal Pt was supported on the grain boundaries and surface of the cerium zirconium composite oxide and alumina of the honeycomb-type precious metal catalyst. Catalyst performance tests were performed on the samples. The sample manufacturing steps and catalyst test conditions were the same as in Comparative Example 2. The test results showed that the ignition temperature of CO was 277°C, the ignition temperature of NO was 273°C, and the ignition temperature of HC was 281°C.

[0088] (Example 44) Cerium zirconium composite oxide-supported precious metal catalyst PtRh / Ce prepared according to Example 23 0.13 Zr 0.64 La 0.03 Nd 0.03 Mn 0.17 Take 200g of O2, take 200g of Pt / Al2O3 prepared according to Example 43, and PtRh / Ce 0.13 Zr 0.64 La 0.03 Nd 0.03 Mn 0.17A coating slurry was prepared by coating O2, Pt / Al2O3, a certain amount of adhesive, an acidity adjuster, and deionized water with a total loading amount of honeycomb catalyst noble metal of 2.5 g / L. This slurry was then coated onto a ceramic honeycomb support, dried at 110°C for 4 hours, heat-treated at 400°C for 3 hours, and finally roasted at 550°C for 6 hours to obtain a honeycomb-type noble metal catalyst. The noble metals Pt and Rh were supported on the grain boundaries and surface of the cerium zirconium composite oxide and alumina of the honeycomb-type noble metal catalyst. Catalyst performance tests were performed on the samples. The sample manufacturing steps and catalyst test conditions were the same as in Comparative Example 2. The test results showed that the ignition temperature of CO was 253°C, the ignition temperature of NO was 249°C, and the ignition temperature of HC was 255°C.

[0089] (Example 45) A coating slurry was prepared by combining 200g of Pt / Al2O3 prepared according to Example 43 with a certain amount of adhesive, acidity adjuster, and deionized water. The alumina slurry was then applied to a ceramic honeycomb support in an amount containing 100g / L of alumina. The coated honeycomb support was dried at 110°C for 4 hours to produce cerium zirconium composite oxide (Ce). 0.30 Zr 0.61 La 0.044 Gd 0.04 Cu 0.006 Take 200g of O2 and Ce 0.30 Zr 0.61 La 0.044 Gd 0.04 Cu 0.006 O2 and a certain amount of adhesive, acidity adjuster, deionized water, etc. are used to make a coating slurry, and Ce 0.30 Zr 0.61 La 0.044 Gd 0.04 Cu 0.006A slurry containing O2 was applied at a coating rate of 100 g / L to the honeycomb support coated with Pt / Al2O3. The coated honeycomb support was dried at 110°C for 4 hours, then heat-treated at 530°C for 7 hours, and finally roasted at 640°C for 5 hours to obtain a honeycomb-type precious metal catalyst. The precious metal Pt was mainly supported on the grain boundaries and surface of the Pt / Al2O3 in the honeycomb-type precious metal catalyst, with small amounts supported on the grain boundaries and surface of cerium zirconium composite oxide and alumina. Catalyst performance tests were performed on the samples. The sample manufacturing steps and catalyst test conditions were the same as in Comparative Example 2. The test results showed that the ignition temperature of CO was 293°C, the ignition temperature of NO was 288°C, and the ignition temperature of HC was 287°C.

[0090] (Example 46) Cerium zirconium complex oxide Ce 0.3 Zr 0.6 La 0.05 Pr 0.05 200g each of O2 and activated alumina were taken and mixed uniformly with a certain amount of deionized water. The honeycomb carrier activated coating contained a load of 0.45% palladium, 0.13% platinum, and 0.01% rhodium. A certain amount of palladium, platinum, and rhodium nitrates were added to the slurry, and a certain amount of adhesive, acidity adjuster, and deionized water was added to prepare a coating slurry. The slurry, prepared with a total load of honeycomb catalyst noble metal of 1.18g / L, was applied to a ceramic honeycomb carrier. The coated honeycomb carrier was dried at 110°C for 4 hours, then heat-treated at 650°C for 4 hours, and finally reduced-roasted under a hydrogen atmosphere at 550°C for 6 hours to obtain a honeycomb-type noble metal catalyst. The noble metals Pd, Pt, and Rh were supported on the grain boundaries and surface of the cerium zirconium composite oxide and alumina of the honeycomb-type noble metal catalyst. Catalyst performance tests were performed on the samples. The sample manufacturing steps and catalyst test conditions were the same as in Comparative Example 2. The test results showed that the ignition temperature of CO was 281°C, the ignition temperature of NO was 294°C, and the ignition temperature of HC was 287°C.

[0091] Based on the above comparative examples and examples, the method for producing catalysts with noble metals supported on grain boundaries and surfaces and honeycomb-type noble metal catalysts provided in the examples of the present invention was adopted. By controlling the atmosphere, temperature, and time of the heat treatment and roasting steps, the obtained catalysts with noble metals supported on grain boundaries and surfaces and honeycomb-type noble metal catalysts were aged at 1000°C for 4 hours and then produced CO and NO. X The ignition temperatures for HC are clearly lower than those of catalysts produced using the conventional method in the comparative example, indicating good high-temperature stability and catalytic activity. The embodiment of the present invention avoids the migration, aggregation, and growth of precious metal particles by diffusing the precious metal into the grain boundaries and surface of an active coating containing cerium zirconium composite oxide or cerium zirconium composite oxide and alumina, thereby maintaining good catalytic activity of the precious metal catalyst, improving high-temperature stability, and reducing the amount of precious metal used.

[0092] As described above, the present invention relates to a catalyst with a precious metal supported on its grain boundaries and surface, a honeycomb-type precious metal catalyst, a method for producing the same, and its applications. The precious metal is dispersed on the grain boundaries and surface of alumina and / or cerium zirconium composite oxide. By supporting and dispersing the precious metal on the grain boundaries and surface of the catalyst, the present invention provides abundant defect sites on the grain boundaries and surface, which can improve the activity of the precious metal, realize an anchoring effect of the precious metal, avoid migration, aggregation, and growth of precious metal particles, maintain the catalytic activity and high-temperature stability of the precious metal catalyst, and reduce the amount of precious metal used.

[0093] It should be understood that the specific embodiments of the present invention described above are used solely to illustrate or interpret the principles of the present invention and are not intended to limit the invention. Therefore, any modifications, equivalent substitutions, improvements, etc., made without departing from the spirit and scope of the invention shall be within the scope of protection of the invention. Furthermore, the appended claims of the present invention are intended to cover all changes and modifications that fall within the appended claims and boundaries, or equivalent forms thereof.

Claims

1. A catalyst having a noble metal supported on its grain boundaries and surface, wherein the catalyst comprises a noble metal G, alumina, and a cerium zirconium composite oxide, the noble metal G being dispersed on the grain boundaries and surface of the alumina and cerium zirconium composite oxide, or the catalyst comprises a noble metal G and a cerium zirconium composite oxide, the noble metal G being dispersed on the grain boundaries and surface of the cerium zirconium composite oxide, and the general chemical formula of the cerium zirconium composite oxide is Ce ｘ Zr ｙ M ｚ O ２－α D δ And here, M is the cation doping element, and D is the anion doping element. 0 ≤ x ≤ 1, 0 ≤ y ≤ 1, 0 ≤ z < 0.5, and x, y, and z satisfy x + y + z = 1, and x and y are not simultaneously 0. A catalyst having noble metals supported at grain boundaries and on its surface, characterized in that 0 ≤ α ≤ 0.1 and 0 < δ ≤ 0.1, and the doping element D includes one or a combination of one or more anions N, F, and P.

2. A honeycomb-type noble metal catalyst, wherein the catalyst comprises a honeycomb carrier, a noble metal G and an active coating, and the active coating comprises alumina and a cerium-zirconium composite oxide Ce ｘ Zr ｙ M ｚ O ２－α D δ , or the active coating comprises cerium-zirconium composite oxide Ce x Zr y M z O 2-α D δ, the noble metal G is dispersed on the grain boundaries and the surface of the active coating, wherein M is the cation doping element, and D is the anion doping element. 0 ≤ x ≤ 1, 0 ≤ y ≤ 1, 0 ≤ z < 0.5, and x, y, and z satisfy x + y + z = 1, and x and y are not simultaneously 0. A honeycomb-type precious metal catalyst characterized in that 0 ≤ α ≤ 0.1 and 0 < δ ≤ 0.1, and the doping element D includes one or a combination of one or more anions N, F, and P.

3. The catalyst according to claim 2, characterized in that the percentage of the cerium zirconium composite oxide relative to the total mass of the active coating is 0 to 100%.

4. The catalyst according to any one of claims 1 to 3, characterized in that the noble metal G at the grain boundaries and surface is in a metallic state, or in a metallic state and an oxidized state.

5. The catalyst according to any one of claims 1 to 3, characterized in that the noble metal G includes one or a combination of one or more of Pt, Pd, Rh, Ir, Os, Ru, Au, and Ag.

6. The catalyst according to claim 5, wherein the doping element M includes one or more combinations of rare earth elements other than cerium, zirconium and transition metal elements other than rare earth elements, alkaline earth metal elements, and Al, Si, Ga, Sn, and Bi, the rare earth elements other than cerium include La, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, Sc, and Y, the transition metal elements include Ti, V, Mn, Fe, Co, Ni, Cu, Zn, Nb, Mo, Hf, Ta, and W, and the alkaline earth metal elements include Be, Mg, Ca, Sr, and Ba.

7. The catalyst according to claim 5, wherein the noble metal G includes one or a combination of one or more of Pt, Pd, Rh, and Ru; the rare earth elements other than cerium include La, Pr, Nd, Sm, Eu, Gd, Tm, Yb, and Y; the transition metal elements include Ti, Mn, Fe, Co, Ni, Cu, Nb, Hf, W, and Mo; and the alkaline earth metal elements include Mg, Sr, and Ba.

8. The honeycomb carrier catalyst according to claim 2, characterized in that the material of the honeycomb carrier is porous ceramics or metal.

9. The catalyst for which a noble metal is supported at grain boundaries and on the surface, as described in claim 1, characterized in that the amount of noble metal G supported in the catalyst is 0.01% to 3% by mass fraction.

10. The honeycomb carrier catalyst according to claim 2, characterized in that the amount of noble metal G supported in the catalyst is 0.01 to 2.8 g / L.

11. The catalyst according to any one of claims 1 to 3, characterized in that the cerium zirconium composite oxide in the catalyst includes a cerium zirconium composite oxide with an elemental gradient distribution and / or a cerium zirconium composite oxide with a core-shell structure.

12. The honeycomb carrier catalyst according to claim 9, characterized in that the amount of noble metal G supported in the catalyst is 0.1 to 2 g / L.

13. The catalyst according to claim 2, characterized in that the percentage of the cerium zirconium composite oxide relative to the total mass of the active coating is 30 to 70%, and the amount of noble metal G supported in the catalyst is 0.1 to 2 g / L.

14. Step S1 involves uniformly mixing a cerium zirconium composite oxide and / or activated alumina with a liquid salt of noble metal G, Step S2 involves performing one or two heat treatments on the product obtained in step S1. The method for producing a catalyst with a noble metal supported on its grain boundaries and surface, according to claim 1, comprising step S3, which involves reducing and roasting the product obtained in step S2 once or twice in air or a reducing atmosphere to obtain a catalyst with a noble metal supported on its grain boundaries and surface of cerium zirconium composite oxide and / or activated alumina.

15. The honeycomb-type precious metal catalyst is coated with one or more coating materials in layers or regions, wherein the coating material includes a mixture of cerium zirconium composite oxide, alumina, alumina with a precious metal supported on the grain boundaries and surface, alumina with a precious metal supported on the grain boundaries and surface, cerium zirconium composite oxide, and alumina with a precious metal supported on the grain boundaries and surface, and the manufacturing step of the honeycomb-type precious metal catalyst is: Step B1 involves uniformly mixing one or more of the aforementioned coating materials with an adhesive, an acidity adjuster, and water in one or more steps to produce a coating slurry. Step B2 involves applying the coating slurry obtained in step B1 to the honeycomb carrier in one or more steps, or applying it to the honeycomb carrier region by region or layer by layer, and then drying it. The method for producing a honeycomb-type precious metal catalyst according to claim 2, comprising step B3, which involves heat-treating and / or roasting the product obtained in step B2 in air or a reducing atmosphere to obtain a honeycomb-type precious metal catalyst.

16. A method for producing a honeycomb-type precious metal catalyst according to claim 2, characterized by uniformly mixing cerium zirconium composite oxide and / or alumina, a precious metal salt or liquid salt of a precious metal, an acidity adjuster, an adhesive and water in one or more steps to produce a coating slurry; coating the obtained slurry onto a honeycomb support in one or more steps, or coating the obtained slurry onto a honeycomb support region by region or layer by layer and drying; and heat-treating and / or reducing the dried honeycomb support in a reducing atmosphere.

17. The method according to any one of claims 14 to 16, characterized in that the heat treatment temperature is 200 to 800°C and the heat treatment time is 0.5 to 24 hours.

18. The method according to any one of claims 14 to 16, characterized in that the roasting temperature is 400 to 700°C and the time is 0.5 to 24 hours.

19. The method according to any one of claims 14 to 16, characterized in that the reducing atmosphere contains one or more of CO and H2.

20. The method according to 14 or 16, characterized in that the liquid salt of the precious metal G includes one or more combinations of molten salts or aqueous solutions of chlorides, nitrates, and acetates.

21. The method according to any one of claims 14 to 16, characterized in that the heat treatment temperature is 400 to 700°C, the heat treatment time is 1 to 12 hours, and the roasting temperature is 450 to 600°C, and the time is 1 to 12 hours.

22. Applications of the catalyst according to claim 1 or 2 in the fields of automotive exhaust gas purification, industrial organic exhaust gas treatment, natural gas catalytic combustion, petrochemicals, hydrogen energy, and batteries.

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