Cerium zirconium composite oxides doped at grain boundaries and surfaces, their manufacturing method and applications

Abstract

The present invention relates to a cerium-zirconium composite oxide doped on the grain boundary and surface, and its manufacturing method and use. The doping elements of the cerium-zirconium composite oxide are located partially or entirely on the grain boundary and surface, thereby increasing the number of defects and vacancies in the cerium-zirconium composite oxide, increasing the oxygen transfer ability, and providing good high-temperature stability. The cerium-zirconium composite oxide can inhibit the transfer, aggregation, and growth of precious metal particles, enhance the high-temperature stability of precious metal catalysts, and reduce the amount of precious metal used, and can be used in fields such as automobile exhaust gas purification, natural gas catalytic combustion, organic exhaust gas purification, and industrial flue gas denitrification treatment.

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. 202210135450.6, filed on February 14, 2022. All contents of the said Chinese patent application are incorporated herein by reference.

[0002] The present invention relates to the technical field of cerium zirconium composite oxides, and more particularly to cerium zirconium composite oxides doped at grain boundaries and surfaces, methods for producing the same, and applications thereof. [Background technology]

[0003] With the improvement of emission standards for automobile exhaust, industrial exhaust, and flue gas both domestically and internationally, the performance requirements for automobile exhaust gas purification catalysts and industrial exhaust gas and flue gas treatment catalysts are also increasing. As automobiles are fluid sources of pollution, the exhaust gas components and properties constantly change during operation, and it is difficult for ordinary catalysts to effectively purify automobile exhaust gas. Therefore, automobile exhaust gas purification catalysts and motorcycle exhaust gas purification catalysts containing precious metals such as platinum, palladium, and rhodium have been developed, and these catalysts utilize an important active coating material, namely cerium zirconium composite oxide. The cerium oxide in cerium zirconium composite oxide has a variable valency, and in an oxidizing or reducing atmosphere, Ce 4+ and Ce 3+A reversible change occurs, giving the cerium zirconium composite oxide oxygen storage and release function, effectively widening the catalyst's air-fuel ratio window and significantly improving the catalytic performance of automotive exhaust gas purification catalysts. Furthermore, cerium zirconium composite oxide improves the dispersion and utilization rate of precious metals supported on the catalyst, thereby significantly reducing the amount of precious metals used in the catalyst. Therefore, cerium zirconium composite oxide is an essential key material for automotive exhaust gas purification catalysts. The environment in which automotive exhaust gas purification catalysts are operated is harsh, with high temperatures that can reach over 900°C in some cases, and they also contain a certain amount of water vapor. As a result, catalysts require high temperature resistance, and cerium zirconium composite oxide requires not only a high specific surface area but also good high-temperature stability. In addition, cerium zirconium composite oxide has broad potential applications in catalysts for natural gas catalytic combustion, industrial organic exhaust gas treatment, and industrial flue gas denitrification.

[0004] The high temperatures of automobile exhaust gases alter the structure of cerium zirconium composite oxides, causing a continuous decrease in specific surface area and performance degradation. In particular, to meet increasingly stringent and improving automobile exhaust gas emission standards, it is necessary to improve the high-temperature stability performance of cerium zirconium composite oxides. Furthermore, in the application of cerium zirconium composite oxides to automobile exhaust gas purification catalysts, the platinum, palladium, and rhodium precious metal particles supported on the cerium zirconium composite oxide easily migrate, aggregate, and grow due to degradation from high-temperature exhaust gases over long periods, thereby causing catalyst deactivation. [Overview of the project] [Problems that the invention aims to solve]

[0005] Based on the above-mentioned conditions of the prior art, the object of the present invention is to provide a cerium zirconium composite oxide doped at grain boundaries and on the surface, a method for producing the same, and its uses. The high-temperature stability of the cerium zirconium composite oxide is improved, the oxygen vacancies and defects are increased, and catalysts produced using this are advantageous for the highly efficient support of precious metal particles, suppressing the migration, aggregation, and growth of precious metal particles, thereby improving the high-temperature stability performance of the catalyst. [Means for solving the problem]

[0006] To achieve the above objective, a first aspect of the present invention provides a cerium zirconium composite oxide doped at grain boundaries and on the surface, wherein the chemical formula of the cerium zirconium composite oxide is Ce x Zr 1-x-y M y O 2-α D δ And here, M is the cation doping element, and D is the anion doping element. 0.1 ≤ x ≤ 0.9, 0 <y≦0.2、0≦α≦0.1、0≦δ≦0.1である。

[0007] Furthermore, the grain boundaries and surface of the cerium zirconium composite oxide contain one or more of the following: an oxide of doping element M, or a nitrogen-containing compound formed by the oxide of doping element M and M and D, a fluoride, a phosphate, and a sulfate.

[0008] Furthermore, the doping element M is one or more of the following: rare earth elements other than cerium, transition metal elements, alkaline earth metal elements, and Al and Si; and the doping element D is one or more of the following: N, S, F and P.

[0009] Furthermore, the rare earth element is one or more combinations of La, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, Y, and Sc, the transition metal element is one or more combinations of Cu, Mn, Ni, Fe, Zn, Co, Ti, Hf, Cr, and W, and the alkaline earth metal element is one or more combinations of Mg, Ca, Sr, and Ba.

[0010] Furthermore, the doping element M of the cation contains one or more combinations of La, Pr, Nd, Sm, Eu, Yb, Y, Sc, Cu, Mn, Hf, Fe, Co, Al, Si, Mg, Ba, and Sr.

[0011] Furthermore, the specific surface area of the cerium zirconium composite oxide after heat preservation at 1000 °C for 10 h is greater than 50 m 2 / g, preferably greater than 60 m 2 / g, and the specific surface area after heat preservation at 1100 °C for 4 h is greater than 35 m 2 / g, preferably greater than 40 m 2 / g.

[0012] Furthermore, the total pore volume of the cerium zirconium composite oxide is greater than 0.4 mL / g, and the total pore volume after heat preservation at 1000 °C for 10 h is greater than 0.2 mL / g.

[0013] Furthermore, the cerium zirconium composite oxide doped on the grain boundaries and the surface includes an elemental gradient distribution structure or a core-shell structure, preferably a structure in which the outer surface or the shell is rich in cerium oxide, or a structure in which the doping element M is rich on the outer surface, or a structure in which the doping element M is on the outer surface or / and inside, and is one or more of these.

[0014] The second aspect of the present invention provides a method for producing the cerium zirconium composite oxide doped on the grain boundaries and the surface according to the first aspect of the present invention. Step S1 involves separately preparing aqueous solutions containing cerium ions and zirconium ions in stoichiometric ratios required for the product, mixing these to obtain a mixture, and then precipitation the mixture with a basic substance in a reactor in one or two steps, followed by filtering, washing, drying, and roasting the resulting precipitate to obtain a cerium-zirconium-containing oxide. Step S2 includes mixing the cerium zirconium-containing oxide obtained in step S1 with liquid salts of doping elements M and D, drying, performing one or two heat treatments, and further performing one or two roastings to obtain a cerium zirconium composite oxide doped at the grain boundaries and surface.

[0015] Furthermore, the aqueous solution containing zirconium ions in step S1 includes one or more aqueous solutions of zirconium oxychloride, zirconium oxynitrate, zirconium sulfate, zirconium acetate, and zirconium citrate.

[0016] Furthermore, the aqueous solution containing cerium ions in step S1 includes one or more aqueous solutions of cerium chloride, cerium nitrate, cerium sulfate, cerium acetate, and cerium citrate.

[0017] Furthermore, the basic substance comprises at least one of the hydroxides, carbonates, or bicarbonates of at least one element from among magnesium bicarbonate, urea, ammonium, sodium, and potassium, and preferably at least one of sodium hydroxide, urea, aqueous ammonia, and ammonium bicarbonate.

[0018] Furthermore, the pH value during the precipitation process in step S1 is controlled to 4.5 to 14, preferably 5 to 11, the pH value at the endpoint of precipitation is controlled to 8 to 13, preferably 9 to 11, and the reaction temperature during the precipitation process is 0 to 120°C, preferably 20 to 80°C.

[0019] Furthermore, the liquid salt of the doping element M includes one or more combinations of molten salts or aqueous solutions of chlorides, nitrates, sulfates, acetates, citrates, amino acid salts, and organosilicon compounds.

[0020] Furthermore, the doping element M is added in one or two steps in steps S1 and S2.

[0021] Furthermore, the doping element D is added in one or two steps in steps S1 and S2.

[0022] Furthermore, the doping element D is added in the form of one or more of the following: nitrates, fluorides, phosphates, and sulfates.

[0023] Furthermore, the roasting temperature in step S1 is 500 to 1050°C, the time is 1 to 24 hours, preferably the roasting temperature is 600 to 950°C, and the time is 3 to 12 hours.

[0024] Furthermore, the heat treatment temperature in step S2 is 100 to 600°C, the time is 0.5 to 24 hours, and preferably the heat treatment temperature is 150 to 450°C, and the time is 1 to 12 hours.

[0025] Furthermore, the roasting temperature in step S2 is 500 to 1050°C, the time is 1 to 24 hours, preferably the roasting temperature is 600 to 950°C, and the time is 3 to 12 hours.

[0026] A third aspect of the present invention provides a catalyst manufactured using a cerium zirconium composite oxide doped at grain boundaries and on the surface as described in the first aspect of the present invention.

[0027] A fourth aspect of the present invention provides applications for the catalyst described in the third aspect of the present invention in the fields of automobile exhaust gas purification, natural gas catalytic combustion, organic exhaust gas purification, and industrial flue gas denitrification treatment. [Effects of the Invention]

[0028] As described above, the present invention provides a cerium zirconium composite oxide doped at grain boundaries and on its surface, a method for producing the same, and its applications, in order to improve the high-temperature stability and catalytic application effect of the cerium zirconium composite oxide. The cerium zirconium composite oxide provided in the present invention contains an oxide of doping element M, or a nitrogen-containing compound formed by the oxide of doping element M and M and D, such as a fluoride, phosphate, and sulfate, at the grain boundaries and on the surface of the cerium zirconium composite oxide, with doping element M, or M and D, located at the grain boundaries and on the surface of the cerium zirconium composite oxide. The interaction between the doping element and the crystal grains of the cerium zirconium composite oxide is enhanced, and the dopant at the grain boundaries plays a role in dispersion and coating of the cerium zirconium crystal grains, thereby enabling the cerium zirconium composite oxide to have good high-temperature stability performance. At the same time, the number of defects and vacancies in the cerium zirconium composite oxide increases, enhancing oxygen transport capacity, effectively improving the catalytic activity of the catalyst, and reducing the amount of precious metal used in the catalyst. Furthermore, this cerium-zirconium composite oxide can suppress the migration, aggregation, and growth of precious metal particles, enhance the high-temperature stability performance of precious metal catalysts, and can be applied in fields such as automotive exhaust gas purification, natural gas catalytic combustion, organic exhaust gas purification, and industrial flue gas denitrification treatment.

[0029] The present invention has the following beneficial technical effects compared to the prior art. (1) The cerium zirconium composite oxide provided in the embodiment of the present invention, which is doped at the grain boundaries and on the surface, contains an oxide of doping element M, or a nitrogen-containing compound formed by the oxide of doping element M and M and D, such as a fluoride, phosphate, and sulfate, at the grain boundaries and on the surface, and the doping element M, or M and D, is located at the grain boundaries and on the surface of the cerium zirconium composite oxide. The cerium zirconium composite oxide has abundant defects and vacancies, and defects located at the grain boundaries are particularly abundant, thereby enhancing the interaction between the doping element and the crystal grains, and the dopants located at the grain boundaries perform dispersion and coating effects on the cerium zirconium crystal grains, thereby improving the high-temperature stability performance of the cerium zirconium composite oxide. (2) The cerium zirconium composite oxide provided in the embodiment of the present invention, doped at the grain boundaries and surface, particularly at the grain boundaries, is given abundant grain defects in the cerium zirconium composite oxide, thereby improving the activity of the dopant, improving the effective utilization rate of the dopant, and promoting the catalytic activity of the dopant. (3) The catalyst produced by applying the doped cerium zirconium composite oxide of the present invention to the grain boundaries and surface and supporting precious metals such as platinum, palladium, and rhodium is advantageous compared to conventional cerium zirconium composite oxides because the cerium zirconium composite oxide has abundant defects and the dopants have high activity and abundant defect sites, allowing for efficient dispersion and support of precious metal catalyst particles such as platinum, palladium, and rhodium. Furthermore, because it has many defect sites, it is effective in improving the catalytic activity of the catalyst and reducing the amount of precious metal used in the catalyst. In addition, the precious metal particles preferentially bind to the dopants at the grain boundaries, and there is a strong interaction between the two, which suppresses the movement, aggregation, and growth of the precious metal catalyst particles at high temperatures and improves the high-temperature stability performance of the catalyst. [Brief explanation of the drawing]

[0030] [Figure 1] This is a flowchart for the production of the grain boundary and surface-doped cerium zirconium composite oxide of the present invention. [Modes for carrying out the invention]

[0031] 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.

[0032] A first aspect of the present invention provides a cerium zirconium composite oxide doped at grain boundaries and surfaces, and the chemical formula of the cerium zirconium composite oxide is Ce x Zr 1-x-y M y O 2-α D δ where M is a cation doping element and D is an anion doping element, 0.1 ≦ x ≦ 0.9, 0 < y ≦ 0.2, 0 ≦ α ≦ 0.1, 0 ≦ δ ≦ 0.1, and preferably 0.01 ≦ δ ≦ 0.08.

[0033] The grain boundaries and surfaces of the cerium zirconium composite oxide contain one or more of an oxide of the doping element M, or a nitrogen-containing compound, fluoride, phosphate, and sulfate formed by the oxide of the doping element M and M and D. The doping element M, or M and D, is located at the grain boundaries and surfaces of the cerium zirconium composite oxide, and the existing form is one or more of an oxide, nitrogen-containing compound, fluoride, phosphate, and sulfate.

[0034] Generally, by doping at grain boundaries and surfaces, one or more of an oxide of the doping element M, or a nitrogen-containing compound, fluoride, phosphate, and sulfate formed by the oxide of the doping element M and M and D can be contained in the grain boundaries and surfaces of the cerium zirconium composite oxide. Furthermore, the doping element M, or M and D, is located at the grain boundaries and surfaces of the cerium zirconium composite oxide, and the existing form is one or more of an oxide, nitrogen-containing compound, fluoride, phosphate, and sulfate. Furthermore, the M element contains at least one of La, Pr, Nd, Y, Sc, Cu, Mn, Hf, Mg, Ba, and Sr at the grain boundaries and surfaces of the cerium zirconium composite oxide, and the molar occupancy of the M element at the grain boundaries and surfaces is 10% to 70%. The D element is preferably at least one of N and S at the grain boundaries and surfaces, and the molar occupancy of the D element at the grain boundaries and surfaces is 10% to 70%. By controlling precipitation parameters, the heat treatment temperature and roasting temperature, time, atmosphere, etc. of the product, the forms and ratios of M and D at the grain boundaries and surfaces are adjusted and controlled.

[0035] By achieving doping at the grain boundaries and surface in the cerium zirconium composite oxide, the oxide has abundant defects and vacancies, particularly defects located at the grain boundaries, which enhances the interaction between the doping element and the crystal grains. Furthermore, the dopants located at the grain boundaries play a role in dispersion and coating of the cerium zirconium crystal grains, thereby improving the high-temperature stability performance of the cerium zirconium composite oxide.

[0036] The doping element M is converted to an oxide at the grain boundaries, on the surface, and within the crystal grains, or M combines with D to form one or more of the nitrogen-containing compounds, fluorides, phosphates, and sulfates, preferably the doping element M is converted to an oxide at the grain boundaries and on the surface of the cerium zirconium composite oxide, and / or M combines with D to form one or more of the nitrogen-containing compounds, fluorides, phosphates, and sulfates, M forms an oxide, and D combines with M to form nitrogen-containing compounds, fluorides, phosphates, sulfates, etc., improving the high-temperature stability of the cerium zirconium composite oxide and allowing adjustment and control of the pore structure or oxygen storage capacity.

[0037] The doping element M may be one or more combinations of rare earth elements other than cerium, transition metal elements, alkaline earth metal elements, and Al and Si, where the rare earth element may be one or more combinations of La, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, Y, and Sc, preferably one or more combinations of La, Pr, Nd, Sm, Eu, Yb, Y, and Sc. The transition metal element may be one or more combinations of Cu, Mn, Ni, Fe, Zn, Co, Ti, Hf, Cr, and W; the alkaline earth metal element may be one or more combinations of Mg, Ca, Sr, and Ba; more preferably, the doping element M of the cation includes one or more combinations of La, Pr, Nd, Sm, Eu, Yb, Y, Sc, Cu, Mn, Hf, Fe, Co, Al, Si, Mg, Ba, and Sr. The doping element D may be one or more combinations of N, S, F, and P, preferably N and S.

[0038] The cerium zirconium composite oxide in question has a specific surface area of ​​50 m² after being heated at 1000°C for 10 hours. 2 Greater than / g, preferably 60m 2 It is larger than / g, and the specific surface area after being kept warm at 1100°C for 4 hours is 35m². 2 Greater than / g, preferably 40m 2 It is greater than / g. Furthermore, the total pore volume of the cerium zirconium composite oxide is greater than 0.4 mL / g, and the total pore volume after incubation at 1000°C for 10 hours is greater than 0.2 mL / g.

[0039] Furthermore, the cerium zirconium composite oxide doped at the grain boundaries and on the surface includes an elemental gradient distribution structure or a core-shell structure, preferably one or more of the following: a structure in which the outer surface or shell is rich in cerium oxide, a structure in which the doping element M is rich on the outer surface, or a structure in which the doping element M is on the outer surface and / or internally. This further improves the high-temperature stability and oxygen storage capacity of the cerium zirconium composite oxide, is advantageous for the dispersion and support of noble metal particles, improves catalytic activity, and reduces the amount of noble metal used. 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. For further features and advantages of the core-shell structure of cerium zirconium composite oxides, please refer to the Chinese patent application filed on September 17, 2020, application number CN202010982980.5, with the title "Cerium Zirconium-Based Composite Oxide with Core-Shell Structure and Method for Producing the Same," and its full description.

[0040] A second aspect of the present invention provides a method for producing a grain boundary and surface-doped cerium zirconium composite oxide as described in the first aspect of the present invention, the flowchart of which is shown in Figure 1. Step S1 involves separately preparing aqueous solutions containing cerium ions and zirconium ions in stoichiometric ratios required for the product, mixing these to obtain a mixture, and then precipitation the mixture with a basic substance in a reactor in one or two steps, followed by filtering, washing, drying, and roasting the resulting precipitate to obtain a cerium-zirconium-containing oxide. Step S2 includes mixing the cerium zirconium-containing oxide obtained in step S1 with liquid salts of doping elements M and D, drying, performing one or two heat treatments, and further performing one or two roastings to obtain a cerium zirconium composite oxide doped at the grain boundaries and surface.

[0041] Here, the aqueous solution containing zirconium ions in step S1 may be one or more aqueous solutions of zirconium oxychloride, zirconium oxynitrate, zirconium sulfate, zirconium acetate, and zirconium citrate; the aqueous solution containing cerium ions may be one or more aqueous solutions of cerium chloride, cerium nitrate, cerium sulfate, cerium acetate, and cerium citrate; the basic substance may be at least one of magnesium bicarbonate, urea, ammonium, sodium, and potassium hydroxides, carbonates, or bicarbonates, preferably at least one of sodium hydroxide, urea, aqueous ammonia, and ammonium bicarbonate. The pH value during the precipitation process in step S1 is controlled to 4.5 to 14, preferably 5 to 11, and the pH value at the endpoint of precipitation is controlled to 8 to 13, preferably 9 to 11. The reaction temperature during the precipitation process is 0 to 120°C, preferably 20 to 80°C. The roasting temperature in step S1 is 500 to 1050°C, and the time is 1 to 24 hours, preferably 600 to 950°C, and the time is 3 to 12 hours.

[0042] The doping element M may be added in one or two steps in steps S1 and S2. For example, the doping element M may be added alone in step S1 or step S2 depending on the stoichiometry required for the product, or a portion may be added in step S1 and the other portion in step S2 depending on the stoichiometry required for the product, and any of the above addition methods may be selected as needed. The molar occupancy of element M at the grain boundaries and surface of the cerium zirconium composite oxide is 10 to 70 mol%. The liquid salt of the doping element M may include one or more combinations of chlorides, nitrates, sulfates, acetates, citrates, amino acid salts, and molten salts or aqueous solutions of organosilicon compounds.

[0043] The doping element D may be added in one or two steps in steps S1 and S2, and, similar to the method of adding doping element M, any of the addition methods may be selected as needed. The molar occupancy of element D at the grain boundaries and surface of the cerium zirconium composite oxide is 10 to 70 mol%. The doping element D may be added as one or more of the nitrates, fluorides, phosphates, and sulfates.

[0044] In step S2, the heat treatment temperature is 100 to 600°C and the time is 0.5 to 24 hours, preferably 150 to 450°C and 1 to 12 hours. Furthermore, different heat treatment methods can be employed, for example, by performing heat treatment in stages to allow more doping elements to penetrate the grain boundaries and surface more uniformly and stably.

[0045] In step S2, the roasting temperature is 500 to 1050°C and the time is 1 to 24 hours, preferably 600 to 950°C and 3 to 12 hours. Furthermore, two roasting stages can be employed, which effectively controls the particle size and dispersibility of the cerium zirconium composite oxide and further improves its high-temperature stability performance.

[0046] In the present invention, doping of doping elements M and D at grain boundaries and surfaces of cerium zirconium composite oxide is obtained by solid-liquid mixing of M and D in the form of ionic solutions or liquid salts with the cerium zirconium-containing oxide in step S2, followed by further heat treatment and roasting after drying, or by adding M and D in the form of ionic solutions or liquid salts in two steps, S1 and S2.

[0047] A third aspect of the present invention provides a catalyst manufactured using a cerium zirconium composite oxide doped at grain boundaries and on the surface as described in the first aspect of the present invention. This catalyst can be applied in fields such as automobile exhaust gas purification, natural gas catalytic combustion, organic exhaust gas purification, and industrial flue gas denitrification.

[0048] A fourth aspect of the present invention provides applications for the catalyst described in the third aspect of the present invention in the fields of automobile exhaust gas purification, natural gas catalytic combustion, organic exhaust gas purification, and industrial flue gas denitrification treatment.

[0049] The present invention will be further described below with reference to specific examples.

[0050] (Comparative Example 1) Molar distribution of cerium zirconium composite oxide Ce 0.50 Zr 0.35 La 0.10 Y 0.05 O 1.98 A mixture of CeCl3, ZrOCl2, LaCl3, and YCl3 with a total metal ion molar concentration of 1.5 mol / L was prepared using 250 mL of a mixture. This mixture was then mixed with a 2.5 mol / L sodium hydroxide solution to induce a precipitation reaction. The precipitation temperature was 25°C, the pH value during the precipitation process was controlled to 10 ± 0.2, and the pH value at the end of the precipitation was 11. The precipitate was then subjected to post-treatment such as filtration and washing to obtain a precursor. The precursor was dried at 110°C for 10 hours and roasted at 800°C for 5 hours to obtain a cerium zirconium composite oxide. The total pore volume of the cerium zirconium composite oxide was 0.353 mL / g, and the total pore volume after high-temperature aging at 1000°C for 10 hours was 0.161 mL / g. The specific surface area of ​​the cerium zirconium composite oxide after high-temperature aging at 1000°C for 10 hours was 47.6 m². 2 The specific surface area after high-temperature aging at 1100°C for 4 hours was 31.5 m² / g. 2 It was / g.

[0051] (Comparative Example 2) Molar distribution of cerium zirconium composite oxide Ce 0.80 Zr 0.10 La 0.05 Nd 0.05 O 1.97A mixture of Ce(NO3)3, ZrO(NO3)2, La(NO3)3, and Nd(NO3)3 with a total metal ion molar concentration of 1.5 mol / L was prepared using 250 mL of a mixture. This mixture was then mixed with a 2.5 mol / L aqueous ammonia solution to induce a precipitation reaction. The precipitation temperature was 25°C, the pH value during the precipitation process was 10 ± 0.2, and the pH value at the end of the precipitation was 11. The precipitate was then subjected to post-treatment such as filtration and washing to obtain a precursor. The precursor was dried at 110°C for 10 hours and roasted at 800°C for 5 hours to obtain a cerium zirconium composite oxide. The total pore volume of the cerium zirconium composite oxide was 0.306 mL / g, and the total pore volume after high-temperature aging at 1000°C for 10 hours was 0.148 mL / g. The specific surface area of ​​the cerium zirconium composite oxide after high-temperature aging at 1000°C for 10 hours was 44.7 m². 2 The specific surface area after high-temperature aging at 1100°C for 4 hours was 30.9 m² / g. 2 It was / g.

[0052] (Example 1) Molar distribution of cerium zirconium composite oxide Ce 0.50 Zr 0.35 La 0.10 Y 0.05 O 1.98 A mixture of CeCl3 and ZrOCl2 with a total metal ion molar concentration of 1.5 mol / L was prepared using 250 mL of a mixture. This mixture was then mixed with a 2.5 mol / L sodium hydroxide solution to induce a precipitation reaction. The precipitation temperature was 25°C, the pH value during the precipitation process was controlled to 10 ± 0.2, and the pH value at the end of the precipitation was 11. The precipitate was then subjected to post-treatment such as filtration and washing to obtain a precursor. The precursor was then dried at 110°C for 10 hours and roasted at 800°C for 5 hours to obtain a cerium zirconium-containing oxide. Cerium zirconium complex oxide Ce 0.50 Zr 0.35 La 0.10 Y 0.05 O 1.98A fixed volume of a mixed solution of La(NO3)3 and Y(NO3)3 with a total metal ion concentration of 1.6 mol / L was prepared using a molar distribution. This mixed solution was then uniformly mixed with the cerium zirconium-containing oxide obtained above, dried, heat-treated at 200°C for 2 hours, and then roasted at 600°C for 5 hours to obtain a cerium zirconium composite oxide, in which La and Y were located at the grain boundaries and on the surface in oxide form. The total pore volume of the cerium zirconium composite oxide was 0.458 mL / g, and the total pore volume after high-temperature aging at 1000°C for 10 hours was 0.230 mL / g. The specific surface area of ​​the cerium zirconium composite oxide after high-temperature aging at 1000°C for 10 hours was 53.2 m². 2 The specific surface area after high-temperature aging at 1100°C for 4 hours was 36.4 m² / g. 2 It was / g.

[0053] (Example 2) Molar distribution of cerium zirconium composite oxide Ce 0.80 Zr 0.10 La 0.05 Nd 0.05 O 1.97 A mixture of Ce(NO3)3 and ZrO(NO3)2 with a total metal ion molar concentration of 1.5 mol / L was prepared using 250 mL of a mixture. This mixture was then mixed with a 2.5 mol / L aqueous ammonia solution to induce a precipitation reaction. The precipitation temperature was 25°C, the pH value during the precipitation process was controlled to 10 ± 0.2, and the pH value at the end of the precipitation was 11. The precipitate was then subjected to post-treatment such as filtration and washing to obtain a precursor. The precursor was then dried at 110°C for 10 hours and roasted at 800°C for 5 hours to obtain a cerium zirconium-containing oxide. Cerium zirconium complex oxide Ce 0.80 Zr 0.10 La 0.05 Nd 0.05 O 1.97A fixed volume of a mixed solution of La(NO3)3 and Nd(NO3)3 with a total metal ion concentration of 1.1 mol / L was prepared using a molar distribution. This mixed solution was then uniformly mixed with the cerium zirconium-containing oxide obtained above. After drying, the mixture was heat-treated at 300°C for 1 hour, and then roasted at 800°C for 3 hours to obtain a cerium zirconium composite oxide, in which La and Nd were located at the grain boundaries and on the surface in oxide form. The total pore volume of the cerium zirconium composite oxide was 0.423 mL / g, and after high-temperature aging at 1000°C for 10 hours, the total pore volume was 0.209 mL / g. The specific surface area of ​​the cerium zirconium composite oxide after high-temperature aging at 1000°C for 10 hours was 50.8 m². 2 The specific surface area after high-temperature aging at 1100°C for 4 hours was 35.6 m² / g. 2 It was / g.

[0054] (Example 3) Molar distribution of cerium zirconium composite oxide Ce 0.40 Zr 0.50 La 0.05 Nd 0.05 O 1.96 A mixture of Ce(NO3)3 and ZrO(NO3)2 with a total metal ion molar concentration of 1.5 mol / L was prepared using 250 mL of a mixture. This mixture was then mixed with a 2.5 mol / L aqueous ammonia solution to induce a precipitation reaction. The precipitation temperature was 45°C, the pH value during the precipitation process was controlled to 6 ± 0.2, and the pH value at the end of the precipitation was 9.5. The precipitate was then subjected to post-treatment such as filtration and washing to obtain a precursor. The precursor was then dried at 110°C for 10 hours and roasted at 800°C for 5 hours to obtain a cerium zirconium-containing oxide. A fixed volume of a mixed solution of La(NO3)3 and Nd(NO3)3 with a total metal ion concentration of 2.5 mol / L was prepared by mixing it with the cerium zirconium composite oxide. This mixed solution was then uniformly mixed with the cerium zirconium-containing oxide obtained above, dried, heat-treated at 300°C for 5 hours, and then roasted at 800°C for 3 hours to obtain the cerium zirconium composite oxide, in which La and Nd were located at the grain boundaries and on the surface in oxide form. The total pore volume of the cerium zirconium composite oxide was 0.433 mL / g, and the total pore volume after high-temperature aging at 1000°C for 10 hours was 0.229 mL / g. The specific surface area of ​​the cerium zirconium composite oxide after high-temperature aging at 1000°C for 10 hours was 53.8 m². 2 The specific surface area after high-temperature aging at 1100°C for 4 hours was 36.6 m² / g. 2 It was / g.

[0055] (Example 4) Molar distribution of cerium zirconium composite oxide Ce 0.25 Zr 0.65 La 0.05 Y 0.05 O 1.97 A mixture of Ce(NO3)3, La(NO3)3, and ZrO(NO3)2 with a total metal ion molar concentration of 1.5 mol / L was prepared using a compounding method. This mixture was then mixed with a 2.5 mol / L aqueous ammonia solution to induce a precipitation reaction. The precipitation temperature was 55°C, the pH value during the precipitation process was controlled to 6 ± 0.2, and the pH value at the end of the precipitation was 9.5. The precipitate was then subjected to post-treatment such as filtration and washing to obtain a precursor. The precursor was then dried at 110°C for 10 hours and roasted at 750°C for 5 hours to obtain lanthanum-containing cerium zirconium oxide. A fixed volume of a 2.5 mol / L Y(NO3)3 solution was prepared by mixing it with the cerium zirconium composite oxide in a molar ratio. The Y(NO3)3 solution was then uniformly mixed with the lanthanum-containing cerium zirconium oxide obtained above, dried, heat-treated at 500°C for 5 hours, and then roasted at 850°C for 3 hours to obtain the cerium zirconium composite oxide, in which Y was located at the grain boundaries and on the surface in oxide form. The total pore volume of the cerium zirconium composite oxide was 0.401 mL / g, and the total pore volume after high-temperature aging at 1000°C for 10 hours was 0.201 mL / g. The specific surface area of ​​the cerium zirconium composite oxide after high-temperature aging at 1000°C for 10 hours was 50.1 m². 2 The specific surface area after high-temperature aging at 1100°C for 4 hours was 35.1 m² / g. 2 It was / g.

[0056] (Example 5) Molar distribution of cerium zirconium composite oxide Ce 0.80 Zr 0.05 Nd 0.15 O 1.95 S 0.05 A mixture of CeCl3 and ZrOCl2 with a total metal ion molar concentration of 1.5 mol / L was prepared using a compounding method. An appropriate amount of 1.0 mol / L sulfuric acid solution as a coordinating agent was added, sulfuric acid was introduced, and the mixture was uniformly mixed. This mixture was then mixed with a 2.5 mol / L sodium hydroxide solution to induce a precipitation reaction. The precipitation temperature was 25°C, the pH value during the precipitation process was 10-14, and the pH value at the end of the precipitation was 12. The precipitate was subjected to post-treatment such as filtration and washing to obtain a precursor. The precursor was dried at 110°C for 10 hours and roasted at 500°C for 10 hours to obtain a cerium zirconium-containing oxide. Cerium zirconium complex oxide Ce 0.80 Z r0.05 Nd 0.15 O 1.95 S 0.05A 1.50 mol / L Nd(NO3)3 solution and a 0.4 mol / L (NH4)2SO4 solution were prepared by mixing them in a certain volume according to the molar distribution. The Nd(NO3)3 solution and the (NH4)2SO4 solution were sequentially and gradually mixed uniformly with the cerium zirconium-containing oxide obtained above, dried, heat-treated at 200 °C for 24 hours, and then calcined at 600 °C for 6 hours to obtain a cerium zirconium composite oxide, which contained elements Nd and S at its grain boundaries and surfaces, and existed in the forms of neodymium oxide and neodymium sulfate respectively. The total pore volume of the cerium zirconium composite oxide was 0.402 mL / g, and the total pore volume after high-temperature aging at 1000 °C for 10 hours was 0.204 mL / g. The specific surface area of the cerium zirconium composite oxide after high-temperature aging at 1000 °C for 10 hours was 50.2 m 2 / g, and the specific surface area after high-temperature aging at 1100 °C for 4 hours was 35.1 m 2 / g.

[0057] (Example 6) For the cerium zirconium composite oxide with a molar distribution of Ce 0.40 Zr 0.40 La 0.05 Nd 0.10 Y 0.05 O 1.96 A 270 mL mixture of Ce(NO3)3, ZrO(NO3)2, and La(NO3)3 with a total metal ion molar concentration of 1.4 mol / L was prepared according to the molar distribution. The mixture was mixed with a 2.4 mol / L ammonium bicarbonate solution for precipitation reaction. The precipitation temperature was 30 °C, the pH value during the precipitation process was 7 ± 0.2, the pH value at the end point of precipitation was 8. Post-treatments such as filtration and washing were performed on the precipitate to obtain a precursor, and the precursor was dried at 110 °C for 10 hours and calcined at 500 °C for 24 hours to obtain a cerium zirconium-containing oxide. For the cerium zirconium composite oxide Ce 0.40 Zr 0.40 La 0.05 Nd 0.10 Y 0.05 O 1.96A mixed solution of Nd(NO3)3 and Y(NO3)3 with a total metal ion concentration of 1.6 mol / L was prepared by mixing in a certain volume according to the molar distribution. The mixed solution of Nd(NO3)3 and Y(NO3)3 was uniformly mixed with the cerium zirconium-containing oxide obtained above, dried, heat-treated at 300 °C for 12 hours, and then calcined at 800 °C for 12 hours to obtain a cerium zirconium composite oxide. Elements Nd and Y were contained in its grain boundaries and surface, both of which existed in the form of oxides. The total pore volume of the cerium zirconium composite oxide was 0.462 mL / g, and the total pore volume after high-temperature aging at 1000 °C for 10 hours was 0.236 mL / g. The specific surface area of the cerium zirconium composite oxide after high-temperature aging at 1000 °C for 10 hours was 54.6 m 2 / g, and the specific surface area after high-temperature aging at 1100 °C for 4 hours was 36.8 m 2 / g.

[0058] (Example 7) For the cerium zirconium composite oxide with a molar distribution of Ce 0.40 Zr 0.50 La 0.10 O 1.95 P 0.05 , 290 mL of a mixed solution of CeCl3 and ZrOCl2 with a total metal ion molar concentration of 1.3 mol / L was prepared. The mixed solution was mixed with a 2.2 mol / L sodium carbonate solution for a precipitation reaction. The precipitation temperature was 50 °C, the pH value during the precipitation process was controlled to be 9 ± 0.2, the pH value at the end point of the precipitation was 10. Post-treatments such as filtration and washing were performed on the precipitate to obtain a precursor. Then the precursor was dried at 110 °C for 10 hours and calcined at 600 °C for 8 hours to obtain a cerium zirconium-containing oxide. For the cerium zirconium composite oxide Ce 0.40 Zr 0.50 La 0.10 O 1.95 P[[ID=三十]] 0.05A fixed volume of 1.0 mol / L La(NO3)3 solution and 0.5 mol / L ammonium phosphate solution were prepared by mixing them in a molar ratio. The La(NO3)3 solution and ammonium phosphate solution were then sequentially and uniformly mixed with the cerium zirconium-containing oxide obtained above. After drying, the mixture was heat-treated at 400°C for 6 hours, and then roasted at 800°C for 8 hours to obtain a cerium zirconium composite oxide. La was present in the form of oxide and phosphate at the grain boundaries and on the surface of the cerium zirconium composite oxide. The total pore volume of the cerium zirconium composite oxide was 0.468 mL / g, and the total pore volume after high-temperature aging at 1000°C for 10 hours was 0.240 mL / g. The specific surface area of ​​the cerium zirconium composite oxide after high-temperature aging at 1000°C for 10 hours was 55.1 m². 2 The specific surface area after high-temperature aging at 1100°C for 4 hours was 37.2 m² / g. 2 It was / g.

[0059] (Example 8) Molar distribution of cerium zirconium composite oxide Ce 0.333 Zr 0.581 La 0.044 Pr 0.042 O 1.98 A mixture of CeCl3 and ZrOCl2 with a total metal ion molar concentration of 1.5 mol / L was prepared using 250 mL of a mixture. This mixture was then mixed with a 2.5 mol / L sodium hydroxide solution to induce a precipitation reaction. The precipitation temperature was 60°C, the pH value during the precipitation process was controlled to 10 ± 0.2, and the pH value at the end of the precipitation was 11. The precipitate was then subjected to post-treatment such as filtration and washing to obtain a precursor. The precursor was then dried at 110°C for 10 hours and roasted at 750°C for 6 hours to obtain a cerium zirconium-containing oxide. Cerium zirconium complex oxide Ce 0.333 Zr 0.581 La 0.044 Pr 0.042 O 1.98A mixed solution of La(NO3)3 and Pr(NO3)3 with a total metal ion concentration of 1.0 mol / L was prepared by compounding a fixed volume of these solutions. The La(NO3)3 and Pr(NO3)3 mixed solution was then uniformly mixed with the cerium zirconium-containing oxide obtained above. After drying, the mixture was heat-treated at 300°C for 6 hours, and then roasted at 800°C for 6 hours to obtain a cerium zirconium composite oxide. La and Pr were present in oxide form at the grain boundaries and on the surface of the cerium zirconium composite oxide. The total pore volume of the cerium zirconium composite oxide was 0.523 mL / g, and after high-temperature aging at 1000°C for 10 hours, the total pore volume was 0.259 mL / g. The specific surface area of ​​the cerium zirconium composite oxide after high-temperature aging at 1000°C for 10 hours was 56.9 m². 2 The specific surface area after high-temperature aging at 1100°C for 4 hours was 40.2 m² / g. 2 It was / g.

[0060] (Example 9) Molar distribution of cerium zirconium composite oxide Ce 0.373 Zr 0.520 La 0.044 Y 0.063 O 1.98 A mixture of Ce(NO3)3, ZrO(NO3)2, and La(NO3)3 (50% of the required total amount of La) with a total metal ion molar concentration of 1.5 mol / L was prepared by compounding 250 mL of this mixture. This mixture was then mixed with a 3.0 mol / L aqueous ammonia solution to induce a precipitation reaction. The precipitation temperature was 30°C, the pH value during the precipitation process was 9-12, and the pH value at the end of the precipitation was 9. The precipitate was then subjected to post-treatment such as filtration and washing to obtain a precursor. The precursor was then dried at 110°C for 10 hours and roasted at 700°C for 8 hours to obtain a cerium zirconium-containing oxide. Cerium zirconium complex oxide Ce 0.373 Zr 0.520 La 0.044 Y 0.063 O 1.98A mixed solution of La(NO3)3 (50% of the required total amount of La) and Y(NO3)3 with a total metal ion concentration of 1.0 mol / L was prepared by compounding a fixed volume of these solutions. The La(NO3)3, Y(NO3)3 mixed solution was then uniformly mixed with the cerium zirconium-containing oxide obtained above, dried, heat-treated at 350°C for 6 hours, and then roasted at 700°C for 8 hours to obtain a cerium zirconium composite oxide. La and Y were present in oxide form at the grain boundaries and on the surface of the cerium zirconium composite oxide. The total pore volume of the cerium zirconium composite oxide was 0.491 mL / g, and the total pore volume after high-temperature aging at 1000°C for 10 hours was 0.248 mL / g. The specific surface area of ​​the cerium zirconium composite oxide after high-temperature aging at 1000°C for 10 hours was 55.8 m². 2 The specific surface area after high-temperature aging at 1100°C for 4 hours was 37.9 m² / g. 2 It was / g.

[0061] (Example 10) Molar distribution of cerium zirconium composite oxide Ce 0.55 Zr 0.25 La 0.15 Cu 0.05 O 1.95 A mixture of Ce(NO3)3 and ZrO(NO3)2 with a total metal ion molar concentration of 1.0 mol / L was prepared using a compounding method. This mixture was then mixed with a 2.2 mol / L urea solution and added to an autoclave. The temperature was gradually increased to 120°C, and a hydrothermal reaction was carried out for 8 hours. The precipitate product was subjected to post-treatment such as filtration and washing to obtain a precursor. The precursor was then dried at 110°C for 10 hours and roasted at 800°C for 5 hours to obtain a cerium zirconium-containing oxide. Cerium zirconium complex oxide Ce 0.55 Zr 0.25 La 0.15 Cu 0.05 O 1.95A mixed solution of La(NO3)3 and Cu(NO3)2 with a total metal ion concentration of 2.2 mol / L was prepared by compounding a fixed volume of this solution. This mixed solution was then uniformly mixed with the cerium zirconium-containing oxide obtained above. After drying, the mixture was heat-treated at 600°C for 0.5 hours, and then roasted at 1050°C for 1 hour to obtain a cerium zirconium composite oxide. La and Cu were present in oxide form at the grain boundaries and on the surface of the cerium zirconium composite oxide. The total pore volume of the cerium zirconium composite oxide was 0.443 mL / g, and after high-temperature aging at 1000°C for 10 hours, the total pore volume was 0.219 mL / g. The specific surface area of ​​the cerium zirconium composite oxide after high-temperature aging at 1000°C for 10 hours was 51.7 m². 2 The specific surface area after high-temperature aging at 1100°C for 4 hours was 35.8 m² / g. 2 It was / g.

[0062] (Example 11) Molar distribution of cerium zirconium composite oxide Ce 0.50 Zr 0.35 Ba 0.05 Mn 0.10 O 1.96 A mixture of CeCl3 and ZrOCl2 with a total metal ion molar concentration of 1.2 mol / L was prepared using 320 mL of a mixture. This mixture was then mixed with a 2.1 mol / L sodium hydroxide solution to induce a precipitation reaction. The precipitation temperature was 90°C, the pH value during the precipitation process was 12-14, and the pH value at the end of the precipitation was 13. The precipitate was then subjected to post-treatment such as filtration and washing to obtain a precursor. The precursor was dried at 110°C for 10 hours and roasted at 1050°C for 1 hour to obtain a cerium zirconium-containing oxide. Cerium zirconium complex oxide Ce 0.50 Zr 0.35 Ba 0.05 Mn 0.10 O 1.96A mixed solution of Ba(NO3)2 and Mn(NO3)2 with a total metal ion concentration of 1.6 mol / L was prepared by compounding a fixed volume of this solution. The Ba(NO3)2 and Mn(NO3)2 mixed solution was then uniformly mixed with the cerium zirconium-containing oxide obtained above. After drying, the mixture was heat-treated at 400°C for 6 hours, and then roasted at 700°C for 8 hours to obtain a cerium zirconium composite oxide. Ba and Mn were present in oxide form at the grain boundaries and on the surface of the cerium zirconium composite oxide. The total pore volume of the cerium zirconium composite oxide was 0.451 mL / g, and the total pore volume after high-temperature aging at 1000°C for 10 hours was 0.224 mL / g. The specific surface area of ​​the cerium zirconium composite oxide after high-temperature aging at 1000°C for 10 hours was 52.8 m². 2 The specific surface area after high-temperature aging at 1100°C for 4 hours was 36.2 m² / g. 2 It was / g.

[0063] (Example 12) Molar distribution of cerium zirconium composite oxide Ce 0.330 Zr 0.580 La 0.033 Nd 0.032 Y 0.025 O 1.97 A mixture of CeCl3, ZrOCl2, and LaCl3 with a total metal ion molar concentration of 1.5 mol / L was prepared using 250 mL of a mixture. This mixture was then mixed with a 2.5 mol / L sodium hydroxide solution to induce a precipitation reaction. The precipitation temperature was 45°C, the pH value during the precipitation process was controlled to 10 ± 0.2, and the pH value at the end of the precipitation was 11. The precipitate was then subjected to post-treatment such as filtration and washing to obtain a precursor. The precursor was dried at 110°C for 10 hours and roasted at 850°C for 5 hours to obtain a cerium zirconium-containing oxide. Cerium zirconium complex oxide Ce 0.330 Zr 0.580 La 0.033 Nd 0.032 Y 0.025 O 1.97A mixed solution of Nd(NO3)3 and Y(NO3)3 with a total metal ion concentration of 0.7 mol / L was prepared by compounding a fixed volume of this solution. The Nd(NO3)3 and Y(NO3)3 mixed solution was then uniformly mixed with the cerium zirconium-containing oxide obtained above. After drying, the mixture was heat-treated at 350°C for 6 hours, and then roasted at 850°C for 5 hours to obtain a cerium zirconium composite oxide. The cerium zirconium composite oxide contained Nd and Y elements at the grain boundaries and on the surface, both present in oxide form. The total pore volume of the cerium zirconium composite oxide was 0.548 mL / g, and the total pore volume after high-temperature aging at 1000°C for 10 hours was 0.276 mL / g. The specific surface area of ​​the cerium zirconium composite oxide after high-temperature aging at 1000°C for 10 hours was 57.1 m². 2 The specific surface area after high-temperature aging at 1100°C for 4 hours was 40.9 m² / g. 2 It was / g.

[0064] (Example 13) Molar distribution of cerium zirconium composite oxide Ce 0.18 Zr 0.64 La 0.03 Y 0.15 O 1.96 A mixture of CeCl3, ZrOCl2, and YCl3 with a total metal ion molar concentration of 1.5 mol / L was prepared using 250 mL of a mixture. This mixture was then mixed with a 2.5 mol / L sodium hydroxide solution to induce a precipitation reaction. The precipitation temperature was 50°C, the pH value during the precipitation process was 10-14, and the pH value at the end of the precipitation was 10.5. The precipitate was then subjected to post-treatment such as filtration and washing to obtain a precursor. The precursor was dried at 110°C for 10 hours and roasted at 650°C for 8 hours to obtain a cerium zirconium-containing oxide. Cerium zirconium complex oxide Ce 0.18 Zr 0.64 La 0.03 Y 0.15 O 1.96A 0.5 mol / L La(NO3)3 solution was prepared by compounding a fixed volume with the molar distribution specified above. The La(NO3)3 solution was then uniformly mixed with the cerium zirconium-containing oxide obtained above, dried, heat-treated at 200°C for 10 hours, and then roasted at 650°C for 8 hours to obtain a cerium zirconium composite oxide. La was present in oxide form at the grain boundaries and on the surface of the cerium zirconium composite oxide. The total pore volume of the cerium zirconium composite oxide was 0.582 mL / g, and the total pore volume after high-temperature aging at 1000°C for 10 hours was 0.286 mL / g. The specific surface area of ​​the cerium zirconium composite oxide after high-temperature aging at 1000°C for 10 hours was 57.9 m². 2 The specific surface area after high-temperature aging at 1100°C for 4 hours was 43.8 m² / g. 2 It was / g.

[0065] (Example 14) Molar distribution of cerium zirconium composite oxide Ce 0.16 Zr 0.78 La 0.02 Nd 0.04 O 1.98 A mixture of CeCl3 and ZrOCl2 with a total metal ion molar concentration of 1.5 mol / L was prepared using 250 mL of a mixture. This mixture was then mixed with a 2.5 mol / L sodium hydroxide solution to induce a precipitation reaction. The precipitation temperature was 80°C, the pH value during the precipitation process was 10-14, and the pH value at the end of the precipitation was 10. The precipitate was then subjected to post-treatment such as filtration and washing to obtain a precursor. The precursor was then dried at 110°C for 10 hours and roasted at 600°C for 10 hours to obtain a cerium zirconium-containing oxide. Cerium zirconium complex oxide Ce 0.16 Zr 0.78 La 0.02 Nd 0.04 O 1.98A mixed solution of La(NO3)3 and Nd(NO3)3 with a total metal ion concentration of 0.7 mol / L was prepared by compounding a fixed volume of this solution. The La(NO3)3 and Nd(NO3)3 mixed solution was then uniformly mixed with the cerium zirconium-containing oxide obtained above. After drying, the mixture was heat-treated at 400°C for 6 hours, and then roasted at 600°C for 12 hours to obtain a cerium zirconium composite oxide. La and Nd were present in oxide form at the grain boundaries and on the surface of the cerium zirconium composite oxide. The total pore volume of the cerium zirconium composite oxide was 0.591 mL / g, and the total pore volume after high-temperature aging at 1000°C for 10 hours was 0.289 mL / g. The specific surface area of ​​the cerium zirconium composite oxide after high-temperature aging at 1000°C for 10 hours was 60.2 m². 2 The specific surface area after high-temperature aging at 1100°C for 4 hours was 45.1 m² / g. 2 It was / g.

[0066] (Example 15) Molar distribution of cerium zirconium composite oxide Ce 0.40 Zr 0.40 Al 0.20 O 1.93 N 0.08 A mixture of Ce(NO3)3 and ZrO(NO3)2 with a total metal ion molar concentration of 1.2 mol / L was prepared using 320 mL of a compound. This mixture was then mixed with a 2.2 mol / L aqueous ammonia / ammonium bicarbonate solution and allowed to precipitate. The precipitation temperature was 30°C, the pH value during the precipitation process was 7.5 to 8.5, and the pH value at the end of the precipitation was 8. The precipitate was then subjected to post-treatment such as filtration and washing to obtain a precursor. The precursor was dried at 110°C for 10 hours and roasted at 950°C for 4 hours to obtain a cerium zirconium-containing oxide. Cerium zirconium complex oxide Ce 0.40 Zr 0.40 Al 0.20 O 1.93 N 0.08A 2.2 mol / L Al(NO3)3 solution and a 0.8 mol / L NH4NO3 solution were prepared by mixing them in fixed volumes in the specified molar proportions. The Al(NO3)3 solution and NH4NO3 solution were then uniformly mixed sequentially with the cerium zirconium-containing oxide obtained above. After drying, the mixture was heat-treated at 300°C for 8 hours, and then roasted at 800°C for 6 hours to obtain a cerium zirconium composite oxide. Al was present in the form of an oxide at the grain boundaries and on the surface of the cerium zirconium composite oxide, and N was present in the form of a nitrogen-containing compound at the grain boundaries and on the surface of the cerium zirconium composite oxide. The total pore volume of the cerium zirconium composite oxide was 0.611 mL / g, and the total pore volume after high-temperature aging at 1000°C for 10 hours was 0.301 mL / g. The specific surface area of ​​the cerium zirconium composite oxide after high-temperature aging at 1000°C for 10 hours was 62.4 m². 2 The specific surface area after high-temperature aging at 1100°C for 4 hours was 46.3 m² / g. 2 It was / g.

[0067] (Example 16) Molar distribution of cerium zirconium composite oxide Ce 0.60 Zr 0.30 Ba 0.10 O 1.98 F 0.01 A mixture of CeCl3 and ZrOCl2 with a total metal ion molar concentration of 1.0 mol / L was prepared using 380 mL of a mixture. This mixture was then mixed with a 2.3 mol / L sodium hydroxide solution to induce a precipitation reaction. The precipitation temperature was 20°C, the pH value during the precipitation process was 4.5 to 10, and the pH value at the end of the precipitation was 11. The precipitate was then subjected to post-treatment such as filtration and washing to obtain a precursor. The precursor was dried at 110°C for 10 hours and roasted at 700°C for 8 hours to obtain a cerium zirconium-containing oxide. Cerium zirconium complex oxide Ce 0.60 Zr 0.30 Ba 0.10 O 1.98 F 0.01A fixed volume of 1.0 mol / L Ba(NO3)2 solution and 0.1 mol / L NH4F solution were prepared by mixing them in the specified molar proportions. The Ba(NO3)2 solution and NH4F solution were then uniformly mixed sequentially with the cerium zirconium-containing oxide obtained above. After drying, the mixture was heat-treated at 150°C for 12 hours, and then roasted at 600°C for 12 hours to obtain a cerium zirconium composite oxide. Ba was present in the form of an oxide at the grain boundaries and on the surface of the cerium zirconium composite oxide, and F was present in the form of a fluoride at the grain boundaries and on the surface of the cerium zirconium composite oxide. The total pore volume of the cerium zirconium composite oxide was 0.450 mL / g, and the total pore volume after high-temperature aging at 1000°C for 10 hours was 0.222 mL / g. The specific surface area of ​​the cerium zirconium composite oxide after high-temperature aging at 1000°C for 10 hours was 52.2 m². 2 The specific surface area after high-temperature aging at 1100°C for 4 hours was 36.2 m² / g. 2 It was / g.

[0068] (Example 17) Molar distribution of cerium zirconium composite oxide Ce 0.45 Zr 0.35 Y 0.15 Mg 0.05 O 1.96 A mixture of Ce(NO3)3, ZrO(NO3)2, and Y(NO3)3 with a total metal ion molar concentration of 1.5 mol / L was prepared using 250 mL of a compound solution. This mixture was then mixed with a 3.0 mol / L aqueous ammonia solution to induce a precipitation reaction. The precipitation temperature was 30°C, the pH value during the precipitation process was 9-12, and the pH value at the end of the precipitation was 9. The precipitate was then subjected to post-treatment such as filtration and washing to obtain a precursor. The precursor was dried at 110°C for 10 hours and roasted at 950°C for 3 hours to obtain a cerium zirconium-containing oxide. Cerium zirconium complex oxide Ce 0.45 Zr 0.35 Y 0.15 Mg 0.05 O 1.96A fixed volume of a 0.5 mol / L Mg(NO3)2 solution was prepared using the specified molar distribution. The Mg(NO3)2 solution was then uniformly mixed with the cerium zirconium-containing oxide obtained above. After drying, the mixture was heat-treated at 250°C for 10 hours, followed by roasting at 900°C for 5 hours to obtain a cerium zirconium composite oxide. The element Mg was present in oxide form at the grain boundaries and on the surface of the cerium zirconium composite oxide. The total pore volume of the cerium zirconium composite oxide was 0.438 mL / g, and after high-temperature aging at 1000°C for 10 hours, the total pore volume was 0.221 mL / g. The specific surface area of ​​the cerium zirconium composite oxide after high-temperature aging at 1000°C for 10 hours was 52.9 m². 2 The specific surface area after high-temperature aging at 1100°C for 4 hours was 36.1 m² / g. 2 It was / g.

[0069] (Example 18) Molar distribution of cerium zirconium composite oxide Ce 0.40 Zr 0.45 Pr 0.10 Sm 0.05 O 1.97 A mixture of CeCl3 and ZrOCl2 with a total metal ion molar concentration of 0.8 mol / L was prepared using 470 mL of a mixture. This mixture was then mixed with a 1.0 mol / L sodium hydroxide solution to induce a precipitation reaction. The precipitation temperature was 50°C, the pH value during the precipitation process was 5-9, and the pH value at the end of the precipitation was 10. The precipitate was then subjected to post-treatment such as filtration and washing to obtain a precursor. The precursor was dried at 110°C for 10 hours and roasted at 500°C for 16 hours to obtain a cerium zirconium-containing oxide. Cerium zirconium complex oxide Ce 0.40 Zr 0.45 Pr 0.10 Sm 0.05 O 1.97A mixed solution of Pr(NO3)3 and Sm(NO3)3 with a total metal ion concentration of 1.6 mol / L was prepared by compounding a fixed volume of these solutions. The Pr(NO3)3 and Sm(NO3)3 mixed solution was then uniformly mixed with the cerium zirconium-containing oxide obtained above. After drying, the mixture was heat-treated at 300°C for 8 hours, and then roasted at 500°C for 24 hours to obtain a cerium zirconium composite oxide. The elements Pr and Sm were present in oxide form at the grain boundaries and on the surface of the cerium zirconium composite oxide. The total pore volume of the cerium zirconium composite oxide was 0.451 mL / g, and the total pore volume after high-temperature aging at 1000°C for 10 hours was 0.235 mL / g. The specific surface area of ​​the cerium zirconium composite oxide after high-temperature aging at 1000°C for 10 hours was 54.8 m². 2 The specific surface area after high-temperature aging at 1100°C for 4 hours was 36.9 m² / g. 2 It was / g.

[0070] (Example 19) Molar distribution of cerium zirconium composite oxide Ce 0.20 Zr 0.60 EU 0.10 Co 0.10 O 1.98 A mixture of Ce(NO3)3 and ZrO(NO3)2 with a total metal ion molar concentration of 1.5 mol / L was prepared using 250 mL of a compound. This mixture was then mixed with a 3.0 mol / L aqueous ammonia solution to induce a precipitation reaction. The precipitation temperature was 35°C, the pH value during the precipitation process was 9-12, and the pH value at the end of the precipitation was 9. The precipitate was then subjected to post-treatment such as filtration and washing to obtain a precursor. The precursor was then dried at 110°C for 10 hours and roasted at 600°C for 12 hours to obtain a cerium zirconium-containing oxide. Cerium zirconium complex oxide Ce 0.20 Zr 0.60 EU 0.10 Co 0.10 O 1.98A mixed solution of Eu(NO3)3 and Co(NO3)2 with a total metal ion concentration of 2.2 mol / L was prepared by compounding a fixed volume of this solution. This mixed solution was then uniformly mixed with the cerium zirconium-containing oxide obtained above. After drying, the mixture was heat-treated at 450°C for 1 hour, and then roasted at 800°C for 6 hours to obtain a cerium zirconium composite oxide. Both Eu and Co elements were present in oxide form at the grain boundaries and on the surface of the cerium zirconium composite oxide. The total pore volume of the cerium zirconium composite oxide was 0.552 mL / g, and after high-temperature aging at 1000°C for 10 hours, the total pore volume was 0.279 mL / g. The specific surface area of ​​the cerium zirconium composite oxide after high-temperature aging at 1000°C for 10 hours was 57.3 m². 2 The specific surface area after high-temperature aging at 1100°C for 4 hours was 42.5 m² / g. 2 It was / g.

[0071] (Example 20) Molar distribution of cerium zirconium composite oxide Ce 0.90 Zr 0.05 Gd 0.03 Yb 0.02 O 1.97 A mixture of Ce(NO3)3 and ZrO(NO3)2 with a total metal ion molar concentration of 1.3 mol / L was prepared using 290 mL of a compound solution. This mixture was then mixed with a 3.0 mol / L aqueous ammonia solution to induce a precipitation reaction. The precipitation temperature was 20°C, the pH value during the precipitation process was 9-12, and the pH value at the end of the precipitation was 9. The precipitate was then subjected to post-treatment such as filtration and washing to obtain a precursor. The precursor was then dried at 110°C for 10 hours and roasted at 550°C for 12 hours to obtain a cerium zirconium-containing oxide. Cerium zirconium complex oxide Ce 0.90 Zr 0.05 Gd 0.03 Yb 0.02 O 1.97A mixed solution of Gd(NO3)3 and Yb(NO3)3 with a total metal ion concentration of 0.6 mol / L was prepared by compounding a fixed volume of this solution. This mixed solution was then uniformly mixed with the cerium zirconium-containing oxide obtained above. After drying, it was heat-treated at 350°C for 7 hours, and then roasted at 600°C for 12 hours to obtain a cerium zirconium composite oxide. The composite oxide contained Gd and Yb elements at its grain boundaries and on its surface, both present in oxide form. The total pore volume of the cerium zirconium composite oxide was 0.406 mL / g, and after high-temperature aging at 1000°C for 10 hours, the total pore volume was 0.210 mL / g. The specific surface area of ​​the cerium zirconium composite oxide after high-temperature aging at 1000°C for 10 hours was 50.4 m². 2 The specific surface area after high-temperature aging at 1100°C for 4 hours was 35.3 m² / g. 2 It was / g.

[0072] (Example 21) Molar distribution of cerium zirconium composite oxide Ce 0.70 Zr 0.20 Fe 0.04 Ba 0.04 Sc 0.02 O 1.98 A mixture of CeCl3 and ZrOCl2 with a total metal ion molar concentration of 1.5 mol / L was prepared using 250 mL of a compound. This mixture was then mixed with a 2.5 mol / L sodium hydroxide solution to induce a precipitation reaction. The precipitation temperature was 80°C, the pH value during the precipitation process was 10-14, and the pH value at the end of the precipitation was 10. The precipitate was then subjected to post-treatment such as filtration and washing to obtain a precursor. The precursor was dried at 110°C for 10 hours and roasted at 600°C for 12 hours to obtain a cerium zirconium-containing oxide. Cerium zirconium complex oxide Ce 0.70 Zr 0.20 Fe 0.04 Ba 0.04 Sc 0.02 O 1.98A mixed solution of Fe(NO3)3, Ba(NO3)2, and Sc(NO3)3 with a total metal ion concentration of 1.1 mol / L was prepared by compounding a fixed volume of these solutions. The Fe(NO3)3, Ba(NO3)2, and Sc(NO3)3 mixed solution was then uniformly mixed with the cerium zirconium-containing oxide obtained above. After drying, the mixture was heat-treated at 300°C for 8 hours, and then roasted at 800°C for 7 hours to obtain a cerium zirconium composite oxide. The grain boundaries and surface contained elements Fe, Ba, and Sc, all present in oxide form. The total pore volume of the cerium zirconium composite oxide was 0.431 mL / g, and after high-temperature aging at 1000°C for 10 hours, the total pore volume was 0.217 mL / g. The specific surface area of ​​the cerium zirconium composite oxide after high-temperature aging at 1000°C for 10 hours was 51.6 m². 2 The specific surface area after high-temperature aging at 1100°C for 4 hours was 35.7 m² / g. 2 It was / g.

[0073] (Example 22) Molar distribution of cerium zirconium composite oxide Ce 0.50 Zr 0.45 Mn 0.05 O 1.99 A mixture of CeCl3 and ZrOCl2 with a total metal ion molar concentration of 1.5 mol / L was prepared using 250 mL of a mixture. This mixture was then mixed with a 2.5 mol / L sodium hydroxide solution to induce a precipitation reaction. The precipitation temperature was 0°C, the pH value during the precipitation process was controlled to 9 ± 0.2, and the pH value at the end of the precipitation was 11. The precipitate was then subjected to post-treatment such as filtration and washing to obtain a precursor. The precursor was then dried at 110°C for 10 hours and roasted at 450°C for 18 hours to obtain a cerium zirconium-containing oxide. Cerium zirconium complex oxide Ce 0.50 Zr 0.45 Mn 0.05 O 1.99A fixed volume of Mn(NO3)2 molten salt was prepared using the specified molar proportions. An appropriate amount of Mn(NO3)2 molten salt was uniformly mixed with the cerium zirconium-containing oxide obtained above. After drying, the mixture was heat-treated at 600°C for 0.5 hours, and then roasted at 950°C for 3 hours to obtain a cerium zirconium composite oxide. The composite oxide contained Mn elements at its grain boundaries and on its surface, present in oxide form. The total pore volume of the cerium zirconium composite oxide was 0.404 mL / g, and the total pore volume after high-temperature aging at 1000°C for 10 hours was 0.206 mL / g. The specific surface area of ​​the cerium zirconium composite oxide after high-temperature aging at 1000°C for 10 hours was 50.3 m². 2 The specific surface area after high-temperature aging at 1100°C for 4 hours was 35.2 m² / g. 2 It was / g.

[0074] (Example 23) Molar distribution of cerium zirconium composite oxide Ce 0.40 Zr 0.45 Si 0.10 Hf 0.02 Sr 0.03 O 1.98 A mixture of Ce(NO3)3 and ZrO(NO3)2 with a total metal ion molar concentration of 1.5 mol / L was prepared using 250 mL of a compound solution. This mixture was then mixed with a 3.0 mol / L aqueous ammonia solution to induce a precipitation reaction. The precipitation temperature was 30°C, the pH value during the precipitation process was controlled to 9.0 ± 0.2, and the pH value at the end of the precipitation was 10. The precipitate was then subjected to post-treatment such as filtration and washing to obtain a precursor. The precursor was then dried at 110°C for 10 hours and roasted at 650°C for 10 hours to obtain a cerium zirconium-containing oxide. Cerium zirconium complex oxide Ce 0.40 Zr 0.45 Si 0.10 Hf 0.02 Sr 0.03 O 1.98A mixed solution of ethyl orthosilicate, Sr(NO3)2, and HfO(NO3)2 with a total metal ion concentration of 1.6 mol / L was prepared by compounding a fixed volume of these solutions. This mixed solution was then uniformly mixed with the cerium zirconium-containing oxide obtained above. After drying, the mixture was heat-treated at 350°C for 7 hours, and then roasted at 800°C for 5 hours to obtain a cerium zirconium composite oxide. The grain boundaries and surface contained Si, Sr, and Hf elements, all present in oxide form. The total pore volume of the cerium zirconium composite oxide was 0.467 mL / g, and after high-temperature aging at 1000°C for 10 hours, the total pore volume was 0.229 mL / g. The specific surface area of ​​the cerium zirconium composite oxide after high-temperature aging at 1000°C for 10 hours was 54.9 m². 2 The specific surface area after high-temperature aging at 1100°C for 4 hours was 37.3 m² / g. 2 It was / g.

[0075] (Example 24) Molar distribution of cerium zirconium composite oxide Ce 0.333 Zr 0.581 La 0.044 Pr 0.042 O 1.98 A mixture of CeCl3 and ZrOCl2 with a total metal ion molar concentration of 1.5 mol / L was prepared using 250 mL of a mixture. This mixture was then mixed with a 2.5 mol / L sodium hydroxide solution to induce a precipitation reaction. The precipitation temperature was 60°C, the pH value during the precipitation process was controlled to 10 ± 0.2, and the pH value at the end of the precipitation was 11. The precipitate was then subjected to post-treatment such as filtration and washing to obtain a precursor. The precursor was then dried at 110°C for 10 hours and roasted at 750°C for 6 hours to obtain a cerium zirconium-containing oxide. Cerium zirconium complex oxide Ce 0.333 Zr 0.581 La 0.044 Pr 0.042 O 1.98A mixed solution of La(NO3)3 and Pr(NO3)3 with a total metal ion concentration of 1.0 mol / L was prepared by compounding a fixed volume of these solutions. The La(NO3)3 and Pr(NO3)3 mixed solution was then uniformly mixed with the cerium zirconium-containing oxide obtained above. After drying, the mixture was heat-treated at 250°C for 4 hours, then further heated to 400°C for 5 hours, and finally roasted at 800°C for 6 hours to obtain a cerium zirconium composite oxide. La and Pr were present in oxide form at the grain boundaries and on the surface of the cerium zirconium composite oxide. The total pore volume of the cerium zirconium composite oxide was 0.551 mL / g, and the total pore volume after high-temperature aging at 1000°C for 10 hours was 0.279 mL / g. The specific surface area of ​​the cerium zirconium composite oxide after high-temperature aging at 1000°C for 10 hours was 57.8 m². 2 The specific surface area after high-temperature aging at 1100°C for 4 hours was 41.1 m² / g. 2 It was / g.

[0076] (Example 25) Molar distribution of cerium zirconium composite oxide Ce 0.373 Zr 0.520 La 0.044 Y 0.063 O 1.98 A mixture of Ce(NO3)3, ZrO(NO3)2, and La(NO3)3 (50% of the required total amount of La) with a total metal ion molar concentration of 1.5 mol / L was prepared by compounding 250 mL of this mixture. This mixture was then mixed with a 3.0 mol / L aqueous ammonia solution to induce a precipitation reaction. The precipitation temperature was 30°C, the pH value during the precipitation process was 9-12, and the pH value at the end of the precipitation was 9. The precipitate was then subjected to post-treatment such as filtration and washing to obtain a precursor. The precursor was then dried at 110°C for 10 hours and roasted at 700°C for 8 hours to obtain a cerium zirconium-containing oxide. Cerium zirconium complex oxide Ce 0.373 Zr 0.520 La 0.044 Y 0.063 O 1.98A mixed solution of La(NO3)3 (50% of the required total amount of La) and Y(NO3)3 with a total metal ion concentration of 1.0 mol / L was prepared by compounding a fixed volume of these solutions. The La(NO3)3, Y(NO3)3 mixed solution was then uniformly mixed with the cerium zirconium-containing oxide obtained above. After drying, the mixture was heat-treated at 200°C for 5 hours, then further heated to 450°C for 3 hours, then roasted at 650°C for 5 hours, and finally roasted at 800°C for 3 hours to obtain a cerium zirconium composite oxide. La and Y were present in oxide form at the grain boundaries and on the surface of the cerium zirconium composite oxide. The total pore volume of the cerium zirconium composite oxide was 0.501 mL / g, and the total pore volume after high-temperature aging at 1000°C for 10 hours was 0.254 mL / g. The specific surface area of ​​cerium zirconium composite oxide after high-temperature aging at 1000°C for 10 hours was 56.3 m². 2 The specific surface area after high-temperature aging at 1100°C for 4 hours was 38.4 m² / g. 2 It was / g.

[0077] (Example 26) Molar distribution of cerium zirconium composite oxide Ce 0.380 Zr 0.531 La 0.072 Pr 0.017 O 1.98 A mixture of Ce(NO3)3 and ZrO(NO3)2 with a total metal ion molar concentration of 1.2 mol / L was prepared using a compounding method. This mixture was then mixed with a 2.5 mol / L sodium hydroxide solution to induce a precipitation reaction at a precipitation temperature of 30°C, with a pH of 10-14 during the precipitation process and a pH of 10.5 at the end of the precipitation. A second precipitation reaction was then carried out with the desired LaCl3 solution and sodium hydroxide solution, with a pH of 10.5 at the end of the precipitation. The precipitate was then subjected to post-treatment such as filtration and washing to obtain a precursor. The precursor was dried at 110°C for 10 hours and roasted at 750°C for 5 hours to obtain a core-shell structured cerium zirconium-containing oxide. Cerium zirconium complex oxide Ce 0.380 Zr 0.531 La 0.072 Pr 0.017 O 1.98A solution of Pr(NO3)3 with a total metal ion concentration of 1.0 mol / L was prepared by compounding a fixed volume of Pr(NO3)3 in a molar distribution. The Pr(NO3)3 solution was uniformly mixed with the cerium zirconium-containing oxide obtained above, dried, and then heat-treated at 200°C for 5 hours, further heated to 450°C for 3 hours, and then roasted at 800°C for 3 hours to obtain a core-shell structured cerium zirconium composite oxide. The shell was rich in praseodymium oxide, and La and Pr were present in oxide form at the grain boundaries and on the surface of the cerium zirconium composite oxide. The total pore volume of the cerium zirconium composite oxide was 0.556 mL / g, and the total pore volume after high-temperature aging at 1000°C for 10 hours was 0.287 mL / g. The specific surface area of ​​the cerium zirconium composite oxide after high-temperature aging at 1000°C for 10 hours was 59.5 m². 2 The specific surface area after high-temperature aging at 1100°C for 4 hours was 42.1 m² / g. 2 It was / g.

[0078] (Example 27) Molar distribution of cerium zirconium composite oxide Ce 0.421 Zr 0.470 La 0.045 Y 0.064 O 1.97 A 250 mL mixture containing CeCl3 and ZrOCl2 with a total metal ion molar concentration of 1.0 mol / L was prepared, and this mixture was mixed with a 2.5 mol / L sodium hydroxide solution to induce a precipitation reaction. The precipitation temperature was 60°C, and the pH value during the precipitation process was controlled to 5-11. The pH value was adjusted twice to precipitate in stages. First, the pH value was adjusted to 5 to precipitate zirconium ions, and then the pH value was gradually adjusted to 11 to precipitate cerium ions. The final pH value of the precipitation was 11. The precipitate was subjected to post-treatment such as filtration and washing to obtain a precursor, and the precursor was dried at 110°C for 10 hours and roasted at 750°C for 6 hours to obtain a cerium zirconium-containing oxide with a gradient distribution. Cerium zirconium complex oxide Ce 0.421 Zr 0.470 La 0.045 Y 0.064 O 1.97A mixed solution of La(NO3)3 and Y(NO3)3 with a total metal ion concentration of 1.3 mol / L was prepared by compounding a fixed volume of the La(NO3)3 and Y(NO3)3 mixed solution. This La(NO3)3 and Y(NO3)3 mixed solution was then uniformly mixed with the cerium zirconium-containing oxide obtained above. After drying, the mixture was heat-treated at 150°C for 8 hours, then further heated to 400°C for 5 hours, and finally roasted at 800°C for 5 hours to obtain a cerium zirconium composite oxide. The cerium zirconium composite oxide had an elemental gradient distribution structure, with the exterior rich in cerium oxide, lanthanum oxide, and yttrium oxide, and La and Y present in oxide form at the grain boundaries and on the surface of the cerium zirconium composite oxide. The total pore volume of the cerium zirconium composite oxide was 0.597 mL / g, and the total pore volume after high-temperature aging at 1000°C for 10 hours was 0.295 mL / g. The specific surface area of ​​cerium zirconium composite oxide after high-temperature aging at 1000°C for 10 hours was 62.8 m². 2 The specific surface area after high-temperature aging at 1100°C for 4 hours was 43.1 m² / g. 2 It was / g.

[0079] (Example 28) Molar distribution of cerium zirconium composite oxide Ce 0.239 Zr 0.703 La 0.017 Nd 0.041 O 1.98 A 250 mL mixture containing CeCl3 and ZrOCl2 with a total metal ion molar concentration of 1.5 mol / L was prepared by mixing this mixture with a 2.5 mol / L sodium hydroxide solution to induce a precipitation reaction. The precipitation temperature was 80°C, and the pH value during the precipitation process was controlled to 9-11. A two-stage precipitation was performed, first adjusting the pH to 5 to precipitate zirconium ions, then aging for 1 hour. After that, the pH value was gradually adjusted to 11 to precipitate cerium ions. The final pH value of the precipitation was 11. The precipitate was then subjected to post-treatment such as filtration and washing to obtain a precursor. The precursor was dried at 110°C for 10 hours and roasted at 600°C for 8 hours to obtain a core-shell structured cerium-zirconium-containing oxide. Cerium zirconium complex oxide Ce 0.239 Zr 0.703 La 0.017 Nd0.041 O 1.98 A mixed solution of La(NO3)3 and Nd(NO3)3 with a total metal ion concentration of 1.5 mol / L was prepared by compounding a fixed volume of this solution. The La(NO3)3 and Nd(NO3)3 mixed solution was then uniformly mixed with the cerium zirconium-containing oxide obtained above. After drying, the mixture was heat-treated at 250°C for 4 hours, then further heated to 300°C for 5 hours, and finally roasted at 600°C for 6 hours to obtain a cerium zirconium composite oxide. The cerium zirconium composite oxide had a core-shell structure, with the exterior rich in lanthanum oxide and neodymium oxide, and La and Nd present in oxide form at the grain boundaries and on the surface of the cerium zirconium composite oxide. The total pore volume of the cerium zirconium composite oxide was 0.558 mL / g, and the total pore volume after high-temperature aging at 1000°C for 10 hours was 0.289 mL / g. The specific surface area of ​​cerium zirconium composite oxide after high-temperature aging at 1000°C for 10 hours was 60.8 m². 2 The specific surface area after high-temperature aging at 1100°C for 4 hours was 42.6 m² / g. 2 It was / g.

[0080] (Example 29) Molar distribution of cerium zirconium composite oxide Ce 0.330 Zr 0.576 La 0.035 Nd 0.034 Y 0.025 O 1.98 A 250 mL mixture containing CeCl3 and ZrOCl2 with a total metal ion molar concentration of 1.2 mol / L was prepared by mixing this mixture with a 2.5 mol / L sodium hydroxide solution to induce a precipitation reaction. The precipitation temperature was 60°C, and the pH value during the precipitation process was controlled to 5-10. The pH value was adjusted twice to allow precipitation in stages. First, the pH value was adjusted to 5 to precipitate zirconium ions, and then the pH value was gradually adjusted to 10 to precipitate cerium ions. The final pH value of the precipitation was 10. The precipitate was then subjected to post-treatment such as filtration and washing to obtain a precursor. The precursor was dried at 110°C for 10 hours and roasted at 750°C for 6 hours to obtain a cerium zirconium-containing oxide with a gradient distribution. Cerium zirconium complex oxide Ce 0.330 Zr0.576 La 0.035 Nd 0.034 Y 0.025 O 1.98 A mixed solution of La(NO3)3, Nd(NO3)3, and Y(NO3)3 with a total metal ion concentration of 1.2 mol / L was prepared by compounding a fixed volume of this solution. The La(NO3)3, Nd(NO3)3, and Y(NO3)3 mixed solution was then uniformly mixed with the cerium zirconium-containing oxide obtained above. After drying, the mixture was heat-treated at 200°C for 6 hours, then further heated to 400°C for 5 hours, and finally roasted at 800°C for 5 hours to obtain a cerium zirconium composite oxide. The cerium zirconium composite oxide had an elemental gradient distribution structure, with the exterior rich in lanthanum oxide, neodymium oxide, and yttrium oxide, and La, Nd, and Y present in oxide form at the grain boundaries and on the surface of the cerium zirconium composite oxide. The total pore volume of the cerium zirconium composite oxide was 0.571 mL / g, and the total pore volume after high-temperature aging at 1000°C for 10 hours was 0.299 mL / g. The specific surface area of ​​cerium zirconium composite oxide after high-temperature aging at 1000°C for 10 hours was 62.8 m². 2 The specific surface area after high-temperature aging at 1100°C for 4 hours was 43.1 m² / g. 2 It was / g.

[0081] (Example 30) Molar distribution of cerium zirconium composite oxide Ce 0.184 Zr 0.642 La 0.028 Y 0.146 O 1.98A 250 mL mixture of CeCl3, ZrOCl2, and YCl3 (with 50% Y) with a total metal ion molar concentration of 0.7 mol / L was prepared. This mixture was then mixed with a 2.5 mol / L sodium hydroxide solution to induce a precipitation reaction. The precipitation temperature was 40°C, and the pH value during the precipitation process was controlled to 5-11. The pH value was adjusted twice to allow precipitation in stages. First, the pH value was adjusted to 5 to precipitate zirconium ions, and then the pH value was gradually adjusted to 11 to precipitate cerium ions and yttrium ions. The final pH value of the precipitation was 11. The precipitate was then subjected to post-treatment such as filtration and washing to obtain a precursor. The precursor was dried at 110°C for 10 hours and roasted at 800°C for 5 hours to obtain a cerium zirconium-containing oxide with a gradient distribution. Cerium zirconium complex oxide Ce 0.184 Zr 0.642 La 0.028 Y 0.146 O 1.98 A mixed solution of La(NO3)3 and Y(NO3)3 (with Y making up 50%) with a total metal ion concentration of 1.0 mol / L was prepared by compounding a fixed volume of the La(NO3)3 and Y(NO3)3 mixed solution. This La(NO3)3 and Y(NO3)3 mixed solution was then uniformly mixed with the cerium zirconium-containing oxide obtained above. After drying, the mixture was heat-treated at 250°C for 4 hours, then further heated to 450°C for 1 hour, then roasted at 700°C for 4 hours, and finally roasted at 800°C for 3 hours to obtain a cerium zirconium composite oxide. The cerium zirconium composite oxide had an elemental gradient distribution structure, with the exterior being rich in lanthanum oxide and yttrium oxide, present both on the outer and interior surfaces, and La and Y present in oxide form at the grain boundaries and on the surface of the cerium zirconium composite oxide. The total pore volume of the cerium zirconium composite oxide was 0.599 mL / g, and after high-temperature aging at 1000°C for 10 hours, the total pore volume was 0.301 mL / g. The specific surface area of ​​the cerium zirconium composite oxide after high-temperature aging at 1000°C for 10 hours was 63.1 m². 2 The specific surface area after high-temperature aging at 1100°C for 4 hours was 43.4 m² / g. 2 It was / g.

[0082] (Example 31) Molar distribution of cerium zirconium composite oxide Ce 0.326 Zr 0.569 La 0.043 Y 0.062 O 1.98 A 250 mL mixture of CeCl3 and ZrOCl2 with a total metal ion molar concentration of 0.8 mol / L was prepared, and this mixture was mixed with a 2.5 mol / L sodium hydroxide solution to induce a precipitation reaction at a precipitation temperature of 60°C, with the pH value during the precipitation process controlled to 10-14, and the final pH being 10. A second precipitation reaction was then carried out with the desired LaCl3 solution and sodium hydroxide solution, with the final pH being 10. The precipitate was then subjected to post-treatment such as filtration and washing to obtain a precursor, which was then dried at 110°C for 10 hours and roasted at 750°C for 6 hours to obtain a core-shell structured cerium zirconium-containing oxide. Cerium zirconium complex oxide Ce 0.326 Zr 0.569 La 0.043 Y 0.062 O 1.98 A solution of Y(NO3)3 with a total metal ion concentration of 1.5 mol / L was prepared by compounding a fixed volume of the Y(NO3)3 solution. The Y(NO3)3 solution was uniformly mixed with the cerium zirconium-containing oxide obtained above, dried, and then heat-treated at 350°C for 3 hours, further heated to 400°C for 5 hours, and then roasted at 800°C for 5 hours to obtain a cerium zirconium composite oxide. The cerium zirconium composite oxide had a core-shell structure, with the exterior rich in lanthanum oxide and yttrium oxide, and La and Y were present in oxide form at the grain boundaries and on the surface of the cerium zirconium composite oxide. The total pore volume of the cerium zirconium composite oxide was 0.573 mL / g, and the total pore volume after high-temperature aging at 1000°C for 10 hours was 0.288 mL / g. The specific surface area of ​​the cerium zirconium composite oxide after high-temperature aging at 1000°C for 10 hours was 60.3 m². 2 The specific surface area after high-temperature aging at 1100°C for 4 hours was 42.3 m² / g. 2 It was / g.

[0083] (Example 32) Molar distribution of cerium zirconium composite oxide Ce 0.156 Zr0.763 La 0.041 Nd 0.040 O 1.98 A 250 mL mixture of CeCl3 and ZrOCl2 with a total metal ion molar concentration of 1.0 mol / L was prepared, and this mixture was mixed with a 2.5 mol / L sodium hydroxide solution to induce a precipitation reaction at a precipitation temperature of 60°C, with the pH value during the precipitation process controlled to 10-14, and the final pH being 11. A second precipitation reaction was then carried out with the desired LaCl3 solution and sodium hydroxide solution, with the final pH being 11. The precipitate was then subjected to post-treatment such as filtration and washing to obtain a precursor, which was then dried at 110°C for 10 hours and roasted at 850°C for 4 hours to obtain a core-shell structured cerium zirconium-containing oxide. Cerium zirconium complex oxide Ce 0.156 Zr 0.763 La 0.041 Nd 0.040 O 1.98 A solution of Nd(NO3)3 with a total metal ion concentration of 0.8 mol / L was prepared by compounding a fixed volume of Nd(NO3)3 in a molar distribution. The Nd(NO3)3 solution was uniformly mixed with the cerium zirconium-containing oxide obtained above, dried, and then heat-treated at 250°C for 4 hours, further heated to 300°C for 5 hours, and then roasted at 850°C for 4 hours to obtain a cerium zirconium composite oxide. The cerium zirconium composite oxide had a core-shell structure, with the exterior rich in neodymium oxide and lanthanum oxide, and La and Nd present in oxide form at the grain boundaries and surface of the cerium zirconium composite oxide. The total pore volume of the cerium zirconium composite oxide was 0.598 mL / g, and the total pore volume after high-temperature aging at 1000°C for 10 hours was 0.298 mL / g. The specific surface area of ​​the cerium zirconium composite oxide after high-temperature aging at 1000°C for 10 hours was 60.9 m². 2 The specific surface area after high-temperature aging at 1100°C for 4 hours was 42.9 m² / g. 2 It was / g.

[0084] (Example 33) Molar distribution of cerium zirconium composite oxide Ce 0.163 Zr 0.781 La 0.016 Nd0.040 O 1.98 A 250 mL mixture containing Ce(NO3)3, ZrO(NO3)2, and Nd(NO3)3 (50% Nd) with a total metal ion molar concentration of 1.0 mol / L was prepared by mixing this mixture with a 3.0 mol / L aqueous ammonia solution to induce a precipitation reaction. The precipitation temperature was 35°C, and the pH value during the precipitation process was controlled to 5-10.5. The pH value was adjusted twice to allow precipitation in stages. First, the pH value was adjusted to 5 to precipitate zirconium ions, and then the pH value was gradually adjusted to 10.5 to precipitate cerium ions and neodymium ions. The final pH value of the precipitation was 10.5. The precipitate was subjected to post-treatment such as filtration and washing to obtain a precursor. The precursor was dried at 110°C for 10 hours and roasted at 600°C for 12 hours to obtain a cerium zirconium-containing oxide with a gradient distribution. Cerium zirconium complex oxide Ce 0.163 Zr 0.781 La 0.016 Nd 0.040 O 1.98 A mixed solution of La(NO3)3 and Nd(NO3)3 (50% Nd) with a total metal ion concentration of 1.3 mol / L was prepared by compounding a fixed volume of this solution. The La(NO3)3 and Nd(NO3)3 mixed solution was then uniformly mixed with the cerium zirconium-containing oxide obtained above. After drying, the mixture was heat-treated at 250°C for 4 hours, then further heated to 450°C for 1 hour, and finally roasted at 800°C for 5 hours to obtain a cerium zirconium composite oxide. The cerium zirconium composite oxide had an elemental gradient distribution structure, with the exterior being rich in lanthanum oxide and neodymium oxide, present both externally and internally. La and Nd were present in oxide form at the grain boundaries and on the surface of the cerium zirconium composite oxide. The total pore volume of the cerium zirconium composite oxide was 0.593 mL / g, and the total pore volume after high-temperature aging at 1000°C for 10 hours was 0.294 mL / g. The specific surface area of ​​cerium zirconium composite oxide after high-temperature aging at 1000°C for 10 hours was 62.5 m². 2 The specific surface area after high-temperature aging at 1100°C for 4 hours was 43.2 m² / g. 2 It was / g.

[0085] (Example 34) Molar distribution of cerium zirconium composite oxide Ce 0.523 Zr 0.365 La 0.046 Y 0.066 O 1.98 A 250 mL mixture of Ce(NO3)3 (50% Ce) and ZrO(NO3)2 with a total metal ion molar concentration of 0.7 mol / L is prepared, and this mixture is mixed with a 3 mol / L aqueous ammonia solution to induce a precipitation reaction. The precipitation temperature is 30°C, the pH value during the precipitation process is controlled to 9-11, the final pH is 11, and the desired Y(NO3) is obtained. 3、 A second precipitation reaction was carried out with a mixed solution of Ce(NO3)3 (50% Ce) and a sodium hydroxide solution. The pH value at the endpoint of the precipitation was 10. The precipitate was then subjected to post-treatment such as filtration and washing to obtain a precursor. The precursor was dried at 110°C for 10 hours and roasted at 700°C for 10 hours to obtain a core-shell structured cerium zirconium-containing oxide. Cerium zirconium complex oxide Ce 0.523 Zr 0.365 La 0.046 Y 0.066 O 1.98 A solution of La(NO3)3 with a total metal ion concentration of 1.5 mol / L was prepared by compounding a fixed volume of the La(NO3)3 solution with the cerium zirconium-containing oxide obtained above. The La(NO3)3 solution was then uniformly mixed with the cerium zirconium-containing oxide obtained above, dried, and then heat-treated at 200°C for 4 hours, further heated to 350°C for 4 hours, then heated at 600°C for 5 hours, and finally roasted at 850°C for 3 hours to obtain a cerium zirconium composite oxide. The cerium zirconium composite oxide had a core-shell structure, with the exterior rich in cerium oxide, lanthanum oxide, and yttrium oxide, and La and Y were present in oxide form at the grain boundaries and on the surface of the cerium zirconium composite oxide. The total pore volume of the cerium zirconium composite oxide was 0.599 mL / g, and the total pore volume after high-temperature aging at 1000°C for 10 hours was 0.311 mL / g. The specific surface area of ​​cerium zirconium composite oxide after high-temperature aging at 1000°C for 10 hours was 63.2 m². 2 The specific surface area after high-temperature aging at 1100°C for 4 hours was 43.5 m² / g. 2 It was / g.

[0086] (Example 35) Molar distribution of cerium zirconium composite oxide Ce 0.48 Zr 0.34 La 0.04 Mg 0.06 Mn 0.08 O 1.98 A 250 mL mixture of CeCl3 and ZrOCl2 with a total metal ion molar concentration of 1.5 mol / L was prepared, and this mixture was mixed with a 2.5 mol / L sodium hydroxide solution to induce a precipitation reaction at a precipitation temperature of 35°C, with the pH value during the precipitation process controlled to 9-11, and the final pH being 11. A second precipitation reaction was then carried out with the desired MgCl3 solution and sodium hydroxide solution, with the final pH value being 10.5. The precipitate was then subjected to post-treatment such as filtration and washing to obtain a precursor, which was then dried at 110°C for 10 hours and roasted at 800°C for 8 hours to obtain a core-shell structured cerium zirconium-containing oxide. Cerium zirconium complex oxide Ce 0.48 Zr 0.34 La 0.04 Mg 0.06 Mn 0.08 O 1.98 A fixed volume of a mixed solution of La(NO3)3 and Mn(NO3)3 with a total metal ion concentration of 0.8 mol / L was prepared by compounding the La(NO3)3 and Mn(NO3)3 mixed solution. This mixed solution was then uniformly mixed with the cerium zirconium-containing oxide obtained above. After drying, the mixture was heat-treated at 100°C for 8 hours, then further heated to 400°C for 3 hours, and finally roasted at 700°C for 6 hours to obtain a cerium zirconium composite oxide. The cerium zirconium composite oxide had a core-shell structure, with the exterior rich in manganese oxide and lanthanum oxide, and La, Mn, and Mg present in oxide form at the grain boundaries and on the surface of the cerium zirconium composite oxide. The total pore volume of the cerium zirconium composite oxide was 0.580 mL / g, and the total pore volume after high-temperature aging at 1000°C for 10 hours was 0.289 mL / g. The specific surface area of ​​cerium zirconium composite oxide after high-temperature aging at 1000°C for 10 hours was 61.2 m². 2 The specific surface area after high-temperature aging at 1100°C for 4 hours was 42.8 m² / g. 2It was / g.

[0087] From the data shown in the above examples, it can be seen that the total pore volume of the cerium zirconium composite oxide obtained using the manufacturing method of the examples of the present invention, and the total pore volume after high-temperature aging at 1000°C for 10 hours, are clearly higher than those of the cerium zirconium composite oxide obtained using the manufacturing method of the comparative example. The specific surface area of ​​the cerium zirconium composite oxide obtained using the manufacturing method of the examples of the present invention is higher than that of the cerium zirconium composite oxide obtained using the manufacturing method of the comparative example, both after high-temperature aging at 1000°C for 10 hours and after high-temperature aging at 1100°C for 4 hours. The cerium zirconium composite oxide obtained using the manufacturing method of the examples of the present invention can be obtained with excellent high-temperature stability.

[0088] As described above, the present invention relates to a cerium zirconium composite oxide doped at grain boundaries and on the surface, a method for producing the same, and its applications, thereby improving the high-temperature stability and catalytic application effect of the cerium zirconium composite oxide. The cerium zirconium composite oxide provided in the present invention contains doping elements at its grain boundaries and on its surface, and furthermore, the doping elements are located at its grain boundaries and on its surface, increasing the number of defects and vacancies in the cerium zirconium composite oxide, enhancing its oxygen transport capacity, and providing good high-temperature stability. Moreover, the cerium zirconium composite oxide can suppress the migration, aggregation, and growth of precious metal particles, enhance the high-temperature stability of precious metal catalysts, and can be applied in fields such as automobile exhaust gas purification, natural gas catalytic combustion, organic exhaust gas purification, and industrial flue gas denitrification treatment.

[0089] 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 cerium zirconium composite oxide doped at grain boundaries and on the surface, wherein the chemical formula of the cerium zirconium composite oxide is Ce ｘ Zr １－ｘ－ｙ M ｙ O ２－α D δ And here, M is the cation doping element, and D is the anion doping element. The grain boundaries and surface of the cerium zirconium composite oxide contain an oxide of doping element M, where 0.1 ≤ x ≤ 0.9, 0 < y ≤ 0.2, 0 ≤ α ≤ 0.1, and 0 ≤ δ ≤ 0.1, or the grain boundaries and surface of the cerium zirconium composite oxide contain one or more nitrogen-containing compounds, fluorides, phosphates, and sulfates formed by M and D, as well as an oxide of doping element M. The doping element M is one or more combinations of rare earth elements other than cerium, transition metal elements, alkaline earth metal elements, and Al and Si, and the doping element D is one or more combinations of N, S, F, and P. The cerium zirconium composite oxide is characterized by being doped at grain boundaries and on the surface, and is used in the fields of automobile exhaust gas purification, natural gas catalytic combustion, organic exhaust gas purification, and industrial flue gas denitrification treatment.

2. The cerium zirconium composite oxide doped on grain boundaries and surfaces according to claim 1, characterized in that the rare earth element is one or a combination of one or more of La, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, Y, and Sc; the transition metal element is one or a combination of one or more of Cu, Mn, Ni, Fe, Zn, Co, Ti, Hf, Cr, and W; and the alkaline earth metal element is one or a combination of one or more of Mg, Ca, Sr, and Ba.

3. The cerium zirconium composite oxide doped on grain boundaries and surfaces according to claim 2, characterized in that the doping element M of the cation includes one or more of the following: La, Pr, Nd, Sm, Eu, Yb, Y, Sc, Cu, Mn, Hf, Fe, Co, Al, Si, Mg, Ba, and Sr.

4. The specific surface area of the cerium zirconium composite oxide after heat preservation at 1000 °C for 10 hours is greater than 50 m ２ / g, preferably greater than 60 m ２ / g, and the specific surface area after heat preservation at 1100 °C for 4 hours is greater than 35 m ２ / g, preferably greater than 40 m ２ [[ID=

5. The cerium zirconium composite oxide doped on grain boundaries and surfaces according to claim 1, characterized in that the total pore volume of the cerium zirconium composite oxide is greater than 0.4 mL / g, and the total pore volume after incubation at 1000°C for 10 hours is greater than 0.2 mL / g.

6. Step S1 involves separately preparing aqueous solutions containing cerium ions and zirconium ions in stoichiometric ratios required for the product, mixing these solutions to obtain a mixture, and then precipitation the mixture with a basic substance in a reactor in one or two steps, followed by filtering, washing, drying, and roasting the resulting precipitate to obtain a cerium-zirconium-containing oxide. A method for producing a cerium zirconium composite oxide doped at grain boundaries and on the surface, according to any one of claims 1 to 5, comprising: step S2, which involves mixing the cerium zirconium-containing oxide obtained in step S1 with liquid salts of doping elements M and D, drying, performing one or two heat treatments, and further roasting one or two times to obtain a cerium zirconium composite oxide doped at grain boundaries and on the surface.

7. The method according to 6, characterized in that the aqueous solution containing zirconium ions in step S1 contains one or more aqueous solutions of zirconium oxychloride, zirconium oxynitrate, zirconium sulfate, zirconium acetate, and zirconium citrate.

8. The method according to 6, characterized in that the aqueous solution containing cerium ions in step S1 includes one or a combination of one or more aqueous solutions of cerium chloride, cerium nitrate, cerium sulfate, cerium acetate, and cerium citrate.

9. The method according to 6, characterized in that the basic substance comprises magnesium bicarbonate, urea, and at least one of the hydroxides, carbonates, or bicarbonates of at least one element selected from ammonium, sodium, and potassium.

10. The method according to 6, characterized in that the pH value during the precipitation process in step S1 is 4.5 to 14, the pH value at the endpoint of precipitation is 8 to 13, and the reaction temperature during the precipitation process is 0 to 120°C.

11. The method according to 6, characterized in that the liquid salt of the doping element M comprises one or more combinations of molten salts or aqueous solutions of chlorides, nitrates, sulfates, acetates, citrates, amino acid salts, and organosilicon compounds.

12. The method according to 6, characterized in that the doping element M is added in one or two steps in steps S1 and S2.

13. The method according to 6, characterized in that the doping element D is added in one or two steps in steps S1 and S2.

14. The method according to 13, characterized in that the doping element D is added in the form of one or more of the following: nitrates, fluorides, phosphates, and sulfates.

15. The method according to 6, characterized in that the roasting temperature in step S1 is 500 to 1050°C and the time is 1 to 24 hours.

16. The method according to 6, characterized in that the heat treatment temperature in step S2 is 100 to 600°C and the time is 0.5 to 24 hours.

17. The method according to 6, characterized in that the roasting temperature in step S2 is 500 to 1050°C and the time is 1 to 24 hours.

18. A catalyst characterized by being manufactured using a cerium zirconium composite oxide doped with grain boundaries and surfaces as described in any one of claims 1 to 5.

19. Applications of the catalyst according to claim 18 in the fields of automobile exhaust gas purification, natural gas catalytic combustion, organic exhaust gas purification, and industrial flue gas denitrification treatment.

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