Carbon monoxide removal catalyst and preparation method thereof, and method for preparing cerium dioxide carrier sol

Abstract

The invention discloses a carbon monoxide removal catalyst, a preparation method and a method for preparing cerium dioxide carrier sol, the carbon monoxide removal catalyst comprises: a composite substance, the composite substance comprises a first precious metal salt and a second precious metal salt, the first precious metal salt comprises a first precious metal element, and the second precious metal element comprises a second precious metal element; the first precious metal salt comprises a first precious metal element, the first precious metal element comprises a palladium element and / or a platinum element, the second precious metal salt comprises a second precious metal element, the second precious metal element comprises a ruthenium element and / or a rhodium element, and in the composite substance, the mass ratio of the first precious metal element to the second precious metal element is 1: (0.8-1.6); the shell at least partially covers the outer surface of the composite substance, and the shell comprises a cerium dioxide carrier. The carbon monoxide removal catalyst provided by the invention has a shell-core structure and has relatively high catalytic activity.

Description

Technical Field

[0001] The present application relates to the field of precious metal catalysts, and in particular, to a carbon monoxide removal catalyst and a preparation method thereof, and a method for preparing a cerium dioxide carrier sol. Background Art

[0002] With the rapid development of human society, industrial production has created an ever-increasing demand for energy. At present, fossil energy such as coal and oil still accounts for about 70% of my country's energy consumption. While the use of fossil energy provides stable and sufficient energy, the NO generated by its combustion x , SO2, dust and other by-products also have a huge impact on the environment. Among them, carbon monoxide (CO) gas generated in the oxidation reaction due to incomplete combustion of carbon-containing substances in fossil energy is also included, which is also one of the main polluting gases causing environmental pollution problems. The recovery and treatment of CO is still a challenging topic. When the concentration of CO in the exhaust gas is high, the CO in the exhaust gas can be enriched and recovered through a relatively simple process. The recovered CO is used as fuel gas, chemical raw material, metallurgical industry reducing agent, etc., which also has certain economic value. However, when the CO content in the exhaust gas is low, it is more difficult to recover the CO in the exhaust gas, and the cost of recovery and treatment is high.

[0003] It should be noted that the above statements are only used to provide background technical information related to the present application and do not necessarily constitute prior art. Summary of the invention

[0004] In the first aspect of the present application, the present application proposes a carbon monoxide removal catalyst, comprising: a composite substance, the composite substance comprising a first precious metal salt and a second precious metal salt, the first precious metal salt comprising a first precious metal element, the first precious metal element comprising a palladium element and / or a platinum element, the second precious metal salt comprising a second precious metal element, the second precious metal element comprising a ruthenium element and / or a rhodium element, wherein in the composite substance, the mass ratio of the first precious metal element to the second precious metal element is 1:(0.8-1.6); a shell, the shell at least partially covering the outer surface of the composite substance, the shell comprising a cerium dioxide carrier.

[0005] The carbon monoxide removal catalyst proposed in the present application has a core-shell structure, and the composite material includes a first precious metal and a second precious metal. The two types of precious metals are combined and synergistically in the composite material, so that the carbon monoxide removal catalyst has better catalytic ability; the shell structure containing the cerium dioxide carrier can provide active sites and shielding protection, which can not only load the precious metals and reactants to contact and catalyze chemical reactions on the shell, but also reduce the influence of interferences on the composite material, so that the carbon monoxide removal catalyst can exert a higher catalytic activity.

[0006] In some embodiments, the Dv50 particle size of the composite material is 5 nm to 15 nm. Thus, the composite material has higher catalytic activity and higher selectivity.

[0007] In some embodiments, the thickness of the shell is 15nm-25nm. Thus, the shell has good load capacity and shielding protection capability.

[0008] In the second aspect of the present application, the present application proposes a method for preparing the carbon monoxide removal catalyst, comprising: mixing a first precious metal salt solution and an auxiliary agent aqueous solution in a volume ratio of 1:(0.5-5) and heating them to obtain a first precious metal salt precursor; mixing an alcohol solution of the first precious metal salt precursor with an auxiliary agent alcohol solution in a volume ratio of 1:(3-6) to obtain a first precious metal salt precursor solution; mixing a complexing agent with a second precious metal salt solution and adding them to the first precious metal salt precursor solution, and heating them to obtain a composite substance, wherein the addition rate is 0.5mL / min-1.5mL / min; mixing a demulsifier, a cerium dioxide carrier sol, and a composite substance aqueous solution to obtain a carbon monoxide removal catalyst, wherein the cerium dioxide carrier sol includes a cerium dioxide carrier and an alcohol solvent, the concentration of the composite substance aqueous solution is 10mg / mL-30mg / mL, and the volume ratio of the cerium dioxide carrier sol to the composite substance aqueous solution is (1-1.5):1.

[0009] The method for preparing the carbon monoxide removal catalyst proposed in the present application is to prepare the first noble metal salt and the second noble metal salt under relatively mild reaction conditions in a liquid phase system to obtain a composite material with catalytic ability. The carbon monoxide removal catalyst with a core-shell structure is prepared by impregnating the cerium dioxide carrier sol with the composite material. The preparation process of the method is simple and the process is easy to control.

[0010] In some embodiments, the first noble metal salt includes at least one of palladium tetraamine oxalate, sodium palladiumate, chloropalladic acid, chloroplatinic acid, and potassium hexachloroplatinate. Thus, the first noble metal salt can release the first noble metal ion in the liquid phase.

[0011] In some embodiments, the mass density of the first noble metal salt solution is 10 mg / mL-20 mg / mL, which is beneficial for the preparation of the first noble metal salt precursor.

[0012] In some embodiments, the auxiliary agent aqueous solution includes a surfactant, a reducing agent, a capping agent, and deionized water, wherein the mass ratio of the surfactant, the reducing agent, the capping agent, and the deionized water is 1:(0.4-1):(1.6-5):(6.5-8). Thus, the auxiliary agent aqueous solution and the first noble metal salt are conducive to forming a stable first noble metal salt precursor.

[0013] In some embodiments, the temperature of the mixed heating treatment is 60° C.-90° C., and the time of the mixed heating is 20 min-60 min.

[0014] In some embodiments, the alcohol solution of the first noble metal salt precursor includes the first noble metal salt precursor and an alcohol solvent, and the concentration of the alcohol solution of the first noble metal salt precursor is 15 mg / mL-30 mg / mL. Thus, the first noble metal salt precursor can be uniformly dispersed in the alcohol solvent.

[0015] In some embodiments, the auxiliary alcohol solution includes a surfactant, a reducing agent, and an alcohol solvent, wherein the volume ratio of the surfactant, the reducing agent, and the alcohol solvent is 1:(0.3-1.5):(50-100). Thus, the auxiliary alcohol solution is conducive to the aggregation of the first noble metal salt precursor in the liquid phase to form a stable sol.

[0016] In some embodiments, the mass fraction of the first noble metal salt precursor solution is 10 mg / mL-20 mg / mL.

[0017] In some embodiments, the second noble metal salt solution includes a second noble metal salt, a surfactant, and an alcohol solvent, wherein the ratio of the mass of the second noble metal salt, the mass of the surfactant, and the volume of the alcohol solvent is 1:(100-150):(10-30). Thus, a homogeneous solution containing the second noble metal ions with a stable structure is formed.

[0018] In some embodiments, the second noble metal salt includes at least one of a ruthenium metal salt and a rhodium metal salt, wherein the ruthenium metal salt includes at least one of ruthenium trichloride and ruthenium acetate, and the rhodium metal salt includes at least one of rhodium chloride and rhodium nitrate. Thus, the second noble metal salt can release the second noble metal ion in the liquid phase.

[0019] In some embodiments, the molar ratio of the complexing agent, the second noble metal salt in the second noble metal salt solution, and the first noble metal salt in the first noble metal salt solution is 1:(1.5-3). Thus, in the liquid phase, the complexing agent, the first noble metal ion, the second noble metal ion, and form a stable complex.

[0020] In some embodiments, the demulsifier includes at least one of potassium chloride and sodium chloride.

[0021] In some embodiments, the ceria carrier sol comprises a ceria carrier and an alcohol solvent, wherein the mass ratio of the demulsifier to the ceria carrier is 1:(0.5-1.5), and the mass volume ratio of the ceria carrier to the alcohol solvent is 1:(5-20).

[0022] In some embodiments, the alcohol solvent includes at least one of ethylene glycol, polyethylene glycol 200, diethylene glycol, and tetraethylene glycol. Thus, the alcohol solvent is used as a solvent for the liquid phase system for preparing the carbon monoxide removal catalyst.

[0023] In some embodiments, the complexing agent includes at least one of citric acid monohydrate, oxalic acid, ethylenediaminetetraacetic acid, and glucose. Thus, the organic functional groups of the complexing agent can form a complex with the noble metal ions in the liquid phase.

[0024] In some embodiments, the surfactant includes at least one of polyvinyl pyrrolidone, octadecylamine, polyethylene oxide-polypropylene oxide-polyethylene oxide triblock copolymer, ethylene glycol dimethyl ether, dimethyl sulfoxide, N,N-dimethylformamide, N-methylpyrrolidone, hexadecyltrimethylammonium bromide, and tetrabutylammonium bromide. Thus, the aforementioned surfactant can optimize the surface catalytic activity of the first noble metal ion and the second noble metal ion.

[0025] In the third aspect of the present application, the present application proposes a method for preparing the cerium dioxide carrier sol, comprising: hydrothermally treating a cerium source, a surfactant, a co-solvent, a capping agent, a precipitant, and a mineralizer to obtain the cerium dioxide mixture, wherein the mass ratio of the cerium source, the surfactant, the co-solvent, the capping agent, the precipitant, and the mineralizer is 1:(3-5):(0.5-2):(0.3-0.8):(1-3):(0.1-0.9); calcining the cerium dioxide mixture to obtain a cerium dioxide carrier; wherein the temperature of the hydrothermal treatment is 150°C-200°C, the time of the hydrothermal treatment is 12h-48h, the temperature of the calcination treatment is 250°C-350°C, and the time of the calcination treatment is 2h-6h; and ultrasonically treating the cerium dioxide carrier and the alcohol solvent to obtain the cerium dioxide carrier sol.

[0026] The method for preparing the cerium dioxide carrier sol proposed in the present application prepares the cerium source into a cerium dioxide carrier with a pore structure and converts it into a gel molecule that is stable in an alcohol solvent. The method is simple in process and easy to control. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] The above and / or additional aspects and advantages of the present application will become apparent and easily understood from the description of the embodiments in conjunction with the following drawings, in which:

[0028] Figure 1 This is a carbon monoxide catalytic performance test curve (160° C.) of the carbon monoxide removal catalyst prepared in the examples of this application;

[0029] Figure 2 This is a carbon monoxide catalytic performance test curve (180° C.) of the carbon monoxide removal catalyst prepared in the examples of this application;

[0030] Figure 3 This is a carbon monoxide removal catalyst prepared in the examples of the present application. The carbon monoxide catalytic performance test curve (200°C);

[0031] Figure 4 This is the test curve of the carbon monoxide removal catalyst prepared in the examples of this application in a sulfur-containing environment. DETAILED DESCRIPTION

[0032] The embodiments of the present application are described in detail below. Examples of the embodiments are shown in the drawings, but unnecessary detailed descriptions may be omitted. For example, detailed descriptions of well-known matters and repeated descriptions of actually identical structures may be omitted. This is to avoid the following description from becoming unnecessarily lengthy and to facilitate understanding by those skilled in the art. In addition, the drawings and the following description are provided for those skilled in the art to fully understand the present application and are not intended to limit the subject matter described in the claims.

[0033] Unless otherwise defined, all technical and scientific terms used in this application have the same meanings as those commonly understood by technicians in the technical field to which this application belongs; the terms used in this application are only for the purpose of describing specific embodiments and are not intended to limit this application; unless otherwise specified, the numerical values ​​of the parameters mentioned in this application can be measured using various measurement methods commonly used in the art (for example, they can be tested according to the methods given in the embodiments of this application).

[0034] The terms "including" and "having" in the specification and claims of the present application and any modifications thereof are open expressions, that is, including the contents specified in the present application but not excluding other contents.

[0035] In the description of this application, regardless of whether the words "about" or "approximately" are used, all the numbers disclosed herein are approximate values. The value of each number may differ by less than 10% or a reasonable difference considered by those skilled in the art, such as 1%, 2%, 3%, 4% or 5%.

[0036] "Scope" disclosed in the present application is limited in the form of lower limit and upper limit, and a given range is limited by selecting a lower limit and an upper limit, and the selected lower limit and upper limit define the boundary of a special range. The scope limited in this way can be including end values ​​or not including end values, and can be arbitrarily combined, that is, any lower limit can be combined with any upper limit to form a scope. For example, if the scope of 60-120 and 80-110 is listed for a specific parameter, it is understood that the scope of 60-110 and 80-120 is also expected. In addition, if the minimum range values ​​1 and 2 are listed, and if the maximum range values ​​3, 4 and 5 are listed, the following scope can be all expected: 1-3, 1-4, 1-5, 2-3, 2-4 and 2-5. In the present application, unless otherwise specified, the numerical range "ab" represents the abbreviation of any real number combination between a and b, wherein a and b are real numbers. For example, the numerical range "0-5" means that all real numbers between "0-5" are listed in this document, and "0-5" is just an abbreviation of these numerical combinations. In addition, when a parameter is expressed as an integer ≥ 2, it is equivalent to disclosing that the parameter is, for example, an integer of 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, etc.

[0037] Unless otherwise specified, all embodiments and optional embodiments of the present application can be combined with each other to form a new technical solution.

[0038] Unless otherwise specified, all technical features and optional technical features of this application can be combined with each other to form a new technical solution.

[0039] In the smelting process of the steel industry, the sintering process is to mix and granulate the powdered iron ore, flux and fine coke, ignite the fine coke in the sintering machine, and press the loose iron ore powder and other raw materials into blocks for subsequent blast furnace smelting. The large amount of sintering flue gas generated during the sintering process contains a large amount of CO, accompanied by SO2, NO X , dust and other waste gas pollutants. Due to the characteristics of large gas volume, complex composition, large flue gas temperature fluctuation range, high moisture content and high oxygen content in sintering flue gas, it is difficult to treat and purify sintering flue gas. The average concentration of CO in sintering flue gas can reach 6000ppm-8000ppm, and SO2 in sintering flue gas accounts for 0.6%-1.2%. Even after purification, SO2 in sintering flue gas reaches the emission concentration limit of ≤35mg / m 3, low concentrations of SO2 will still affect the activity of existing CO removal catalysts and the effect of CO catalytic treatment. In order to meet the increasingly stringent environmental protection legal requirements and solve the problem of CO waste pollutant emissions in sintering flue gas, this application proposes a carbon monoxide removal catalyst that can maintain catalytic activity in a sulfide-containing atmosphere, and achieve safe, efficient and green reduction of CO emissions by catalytically oxidizing CO to CO2.

[0040] In the first aspect of the present application, the present application proposes a carbon monoxide removal catalyst, comprising: a composite substance, the composite substance comprising a first precious metal salt and a second precious metal salt, the first precious metal salt comprising a first precious metal element, the first precious metal element comprising a palladium element and / or a platinum element, the second precious metal salt comprising a second precious metal element, the second precious metal element comprising a ruthenium element and / or a rhodium element, wherein in the composite substance, the mass ratio of the first precious metal element to the second precious metal element is 1:(0.8-1.6); a shell, the shell at least partially covering the outer surface of the composite substance, the shell comprising a cerium dioxide carrier.

[0041] The carbon monoxide removal catalyst proposed in the present application has a core-shell structure, and the composite material includes a first noble metal and a second noble metal. The two types of noble metals are combined and coordinated in the composite material, so that the carbon monoxide removal catalyst has good catalytic ability; the shell structure containing the ceria carrier can provide active sites and shielding protection, which can not only load the noble metals and reactants to contact and catalyze chemical reactions on the shell, but also reduce the influence of interferences on the composite material, so that the carbon monoxide removal catalyst can exert a higher catalytic activity. In addition, the carbon monoxide removal catalyst can also allow some free noble metal components to slowly migrate to the surface of the ceria carrier in a low-temperature dry environment without destroying the original core-shell structure, so that the carbon monoxide removal catalyst can maintain a high catalytic activity for a long time.

[0042] In some embodiments, the Dv50 particle size of the composite material is 5 nm to 15 nm. Thus, the composite material has higher catalytic activity and higher selectivity.

[0043] In some embodiments, the shell has a thickness of 15 nm to 25 nm. Thus, the shell has good load capacity and shielding ability.

[0044] In a second aspect of the present application, the present application proposes a method for preparing the carbon monoxide removal catalyst, comprising:

[0045] S1: mixing and heating the first noble metal salt solution and the auxiliary agent aqueous solution in a volume ratio of 1:(0.5-5) to obtain a first noble metal salt precursor;

[0046] The method for preparing the carbon monoxide removal catalyst proposed in the present application is to realize the composite preparation of the first noble metal salt and the second noble metal salt in a liquid phase system by a sol-gel method under relatively mild reaction conditions to obtain a composite substance with catalytic ability. The composite substance is homogeneously distributed in the liquid phase system, and the molecules aggregate to form a gel structure through the impregnation of the cerium dioxide carrier sol and the composite substance, thereby preparing a carbon monoxide removal catalyst with a core-shell structure. The preparation process of this method is simple and the process is easy to control.

[0047] In some embodiments, the first noble metal salt includes at least one of tetraammine palladium oxalate, sodium palladiumate, chloropalladic acid, chloroplatinic acid, and potassium hexachloroplatinate. The first noble metal salt is soluble in water. Thus, the first noble metal salt can release the first noble metal ion in the liquid phase.

[0048] In some embodiments, the mass density of the first noble metal salt solution is 10 mg / mL-20 mg / mL. The mass density of the first noble metal salt solution is within the aforementioned range. After further mixing with the auxiliary aqueous solution, the concentration of the first noble metal ions in the first noble metal salt solution can be relatively evenly dispersed in the liquid phase, and the first noble metal salt precursor is prepared through a hydrothermal reaction. The first noble metal salt precursor forms a homogeneous solution, and the first noble metal precursor molecules aggregate to form a sol structure in the liquid phase system. This is conducive to the preparation of the first noble metal salt precursor.

[0049] In some embodiments, the auxiliary agent aqueous solution includes a surfactant, a reducing agent, a capping agent, and deionized water, wherein the mass ratio of the surfactant, the reducing agent, the capping agent, and the deionized water is 1:(0.4-1):(1.6-5):(6.5-8). The surfactant, the reducing agent, and the capping agent in the auxiliary agent aqueous solution work together to control the aggregation degree of the first noble metal salt precursor molecules and the size of the molecules due to steric hindrance, so as to adjust the particle size of the composite material formed by the first noble metal salt precursor. Thus, it is beneficial for the auxiliary agent aqueous solution to form a stable first noble metal salt precursor with the first noble metal salt and control the particle size of the composite material.

[0050] In some embodiments, the temperature of the mixed heating treatment is 60°C-90°C, and the mixed heating time is 20min-60min. Thus, a slightly boiling heating state is maintained during the mixed heating process, so that the first noble metal salt precursor obtains sufficient energy during the mixed heating process, which helps the first metal salt precursor homogeneous solution to form a gel structure of the first metal precursor during the mixed heating process, so as to promote the appropriate aggregation of the molecules of the first noble metal salt precursor to form a stable first noble metal salt precursor.

[0051] In some embodiments, the prepared first noble metal salt precursor is separated by centrifugation and washed with deionized water to obtain the first noble metal salt precursor.

[0052] In some embodiments, the first noble metal salt precursor is mixed with an alcohol solvent to obtain a first noble metal salt precursor solution.

[0053] S2: mixing the alcohol solution of the first noble metal salt precursor and the auxiliary agent alcohol solution in a volume ratio of 1:(3-6) to obtain a first noble metal salt precursor solution;

[0054] In some embodiments, the alcohol solution of the first noble metal salt precursor includes the first noble metal salt precursor and an alcohol solvent, and the concentration of the alcohol solution of the first noble metal salt precursor is 15 mg / mL-30 mg / mL. Thus, the first noble metal salt precursor can be uniformly dispersed in the alcohol solvent.

[0055] In some embodiments, the auxiliary alcohol solution includes a surfactant, a reducing agent, and an alcohol solvent, wherein the volume ratio of the surfactant, the reducing agent, and the alcohol solvent is 1: (0.3-1.5): (50-100). The coordination of the surfactant and the reducing agent enables the first noble metal to be dispersed in the alcohol solvent and to combine with the reducing agent to form a molecular structure with a network skeleton structure. Thus, the auxiliary alcohol solution is conducive to the aggregation of the first noble metal salt precursor in the liquid phase to form a stable sol structure.

[0056] In some embodiments, before the mixing process, the auxiliary alcohol solution is preheated, wherein the preheating temperature is 160° C.-220° C., and the preheating time is 10 min-50 min.

[0057] In some embodiments, the mass fraction of the first noble metal salt precursor solution is 10 mg / mL-20 mg / mL. Thus, the first noble metal salt precursor can be further combined with the second noble metal ion to prepare a composite material.

[0058] S3: mixing the complexing agent and the second noble metal salt solution, adding the mixture to the first noble metal salt precursor solution, and performing a heating treatment to obtain a composite material, wherein the adding speed is 0.5 mL / min-1.5 mL / min;

[0059] Thus, the second noble metal ions in the second noble metal salt are further complexed with the first noble metal salt precursor to form the composite material.

[0060] In some embodiments, the second noble metal salt solution includes a second noble metal salt, a surfactant, and an alcohol solvent, wherein the ratio of the mass of the second noble metal salt, the mass of the surfactant, and the volume of the alcohol solvent is 1:(100-150):(10-30). After the surfactant combines with the second noble metal ions released by the second noble metal salt, it can affect the distribution of electrons in the ligand molecules containing the second noble metal ions, thereby forming a structurally stable homogeneous solution containing the second noble metal ions.

[0061] In some embodiments, the second noble metal salt includes at least one of a ruthenium metal salt and a rhodium metal salt, wherein the ruthenium metal salt includes at least one of ruthenium trichloride and ruthenium acetate, and the rhodium metal salt includes at least one of rhodium chloride and rhodium nitrate. Thus, the second noble metal salt can release the second noble metal ion in the liquid phase.

[0062] In some embodiments, the molar ratio of the complexing agent, the second noble metal salt in the second noble metal salt solution, and the first noble metal salt in the first noble metal salt solution is 1:(1.5-3). The complexing agent can coordinate with the first noble metal ion released by the first noble metal salt and the second noble metal ion released by the second noble metal salt. Thus, the complexing agent, the first noble metal ion, and the second noble metal ion can form a stable complex.

[0063] S4: Mixing a demulsifier, a cerium dioxide carrier sol, and a composite substance aqueous solution to obtain a carbon monoxide removal catalyst, wherein the cerium dioxide carrier sol includes a cerium dioxide carrier and an alcohol solvent, the concentration of the composite substance aqueous solution is 10 mg / mL-30 mg / mL, and the volume ratio of the cerium dioxide carrier sol to the composite substance aqueous solution is (1-1.5):1.

[0064] Thus, the cerium dioxide carrier gel is infiltrated with the composite material to form the shell of the carbon monoxide removal catalyst. The first noble metal and the second noble metal shell in the composite material penetrate into the lattice of the CeO2 carrier in the shell structure to form a solid solution, which increases the surface oxygen vacancies and is beneficial to improving the catalytic performance of the carbon monoxide removal catalyst.

[0065] In some embodiments, the demulsifier includes at least one of potassium chloride and sodium chloride.

[0066] In some embodiments, the ceria carrier sol comprises a ceria carrier and an alcohol solvent, wherein the mass ratio of the demulsifier to the ceria carrier is 1:(0.5-1.5), and the mass volume ratio of the ceria carrier to the alcohol solvent is 1:(5-20). Thus, the alcohol solvent can fully infiltrate the ceria carrier, so that the ceria carrier remains suspended to form a stable ceria sol.

[0067] In some embodiments, the alcohol solvent includes at least one of ethylene glycol, polyethylene glycol 200, diethylene glycol, and tetraethylene glycol. Thus, the alcohol solvent is used as a solvent for the liquid phase system for preparing the carbon monoxide removal catalyst.

[0068] In some embodiments, the complexing agent includes at least one of citric acid monohydrate, oxalic acid, ethylenediaminetetraacetic acid, and glucose. Thus, the organic functional groups of the complexing agent can form a complex with the noble metal ions in the liquid phase.

[0069] In some embodiments, the surfactant includes at least one of polyvinyl pyrrolidone, octadecylamine, polyethylene oxide-polypropylene oxide-polyethylene oxide triblock copolymer, ethylene glycol dimethyl ether, dimethyl sulfoxide, N,N-dimethylformamide, N-methylpyrrolidone, hexadecyltrimethylammonium bromide, and tetrabutylammonium bromide. The aforementioned surfactant makes the noble metal ions in the liquid phase more uniformly dispersed. Thus, the aforementioned surfactant can optimize the surface catalytic activity of the first noble metal ion and the second noble metal ion.

[0070] In some embodiments, the reducing agent includes at least one of ascorbic acid, citric acid, and potassium borohydride. The reducing agent can be removed by calcination to generate gas and improve the porosity of the carbon monoxide removal catalyst.

[0071] In some embodiments, the carbon monoxide removal catalyst is dried to obtain carbon monoxide removal catalyst particles.

[0072] In the third aspect of the present application, the present application proposes a method for preparing the cerium dioxide carrier sol, comprising:

[0073] S1: hydrothermally treating a cerium source, a surfactant, a co-solvent, a capping agent, a precipitant, and a mineralizer to obtain the cerium dioxide mixture, wherein the mass ratio of the cerium source, the surfactant, the co-solvent, the capping agent, the precipitant, and the mineralizer is 1:(3-5):(0.5-2):(0.3-0.8):(1-3):(0.1-0.9); wherein the temperature of the hydrothermal treatment is 150°C-200°C, and the time of the hydrothermal treatment is 12h-48h.

[0074] S2: calcining the cerium dioxide mixture to obtain a cerium dioxide carrier; the calcination temperature is 250° C.-350° C., and the calcination time is 2 h-6 h;

[0075] S3: subjecting the ceria carrier and the alcohol solvent to ultrasonic treatment to obtain the ceria carrier sol.

[0076] The method for preparing the cerium dioxide carrier sol proposed in the present application prepares the cerium source into a cerium dioxide carrier with a pore structure and converts it into a gel molecule that is stable in an alcohol solvent. The method is simple and easy to control. The method for preparing the cerium dioxide carrier sol proposed in the present application is beneficial to exert the synergistic effect of the first noble metal, the second noble metal and CeO2 in the composite material when preparing a carbon monoxide removal catalyst, and enhances the thermal stability and structural stability of the carbon monoxide removal catalyst through the core-shell structure containing cerium dioxide. Penetrate into the CeO2 lattice to form a structure such as A x Ce 1-x O2 solid solution, A includes the first noble metal and the second noble metal, and increases the surface oxygen vacancies.

[0077] The scheme of the present application is described below by specific examples. It should be noted that the following examples are only used to illustrate the present application and should not be considered as limiting the scope of the present application. If no specific technology or conditions are specified in the examples, the technology or conditions described in the literature in this area or the product instructions are used. The reagents or instruments used are not specified by the manufacturer, and are all conventional products that can be obtained commercially.

[0078] Example 1

[0079] Weigh 120 mg of PVP, 70 mg of ascorbic acid, and 320 mg of potassium bromide, dissolve in 10 ml of deionized water, preheat at 80 °C for 25 min with magnetic stirring, then add 2 ml of 15 mg / ml chloropalladic acid solution, magnetically stir at 85 °C for 2.5 h, filter and wash, and redisperse in 10 ml of polyethylene glycol-200;

[0080] Weigh 100 mg of PVP and 50 mg of ascorbic acid and dissolve them in 10 ml of polyethylene glycol-200, preheat at 200°C for 15 min, weigh 1.5 ml of palladium solution and add it to the above solution, weigh 1 ml of rhodium nitrate solution with a density of 15 mg / ml, mix it into the above solution, continue stirring for 20 min, filter and wash, and redisperse in 10 ml of deionized water;

[0081] Weigh 0.002 mol of cerium nitrate and 0.25 mol of urea, dissolve them in 80 ml of deionized water, and then perform hydrothermal reaction at 150° C. for 18 h. After cooling to room temperature, filter and dry, and calcine at 350° C. for 3 h.

[0082] The solution containing two kinds of precious metals is mixed and impregnated with the carrier sol, and then calcined at 700° C. for 2.5 hours after drying to obtain the desired catalyst.

[0083] Example 2

[0084] Weigh 160 mg of N,N-dimethylformamide, 95 mg of citric acid, and 430 mg of potassium chloride, dissolve in 14 ml of deionized water, preheat at 85°C for 40 min with magnetic stirring, then add 3 ml of sodium palladium solution with a density of 19 mg / ml, magnetically stir at 85°C for 3 h, filter and wash, and redisperse in 15 ml of diethylene glycol;

[0085] Weigh 120 mg of N,N-dimethylformamide and 60 mg of citric acid and dissolve them in 10 ml of diethylene glycol. Preheat at 180°C for 30 min. Measure 2.6 ml of palladium solution and add it to the above solution. Weigh 1.5 ml of ruthenium acetate solution with a density of 18 mg / ml and mix it into the above solution. Continue stirring for 45 min. Filter and wash, and redisperse in 15 ml of deionized water.

[0086] Weigh 0.002 mol of cerium acetate, 0.1 mol of sodium phosphate hexahydrate, and 3 g of octadecylamine, dissolve them in 100 ml of ethylene glycol, and then perform hydrothermal reaction at 200° C. for 24 h. After cooling to room temperature, filter and dry, and calcine at 400° C. for 4 h.

[0087] The solution containing two kinds of precious metals is mixed and impregnated with the carrier sol, and then calcined at 600° C. for 2 hours after drying to obtain the desired catalyst.

[0088] Example 3

[0089] Weigh 180 mg of hexadecyltrimethylammonium bromide, 95 mg of citric acid, and 260 mg of potassium chloride, dissolve in 20 ml of deionized water, preheat at 90 °C for 50 min with magnetic stirring, then add 4 ml of 19 mg / ml chloroplatinic acid solution, magnetically stir at 85 °C for 3 h, filter and wash, and redisperse in 20 ml of tetraethylene glycol;

[0090] Weigh 140 mg of hexadecyltrimethylammonium bromide and 70 mg of citric acid and dissolve them in 16 ml of tetraethylene glycol. Preheat at 200°C for 250 min. Measure 3 ml of palladium solution and add it to the above solution. Weigh 1.5 ml of rhodium acetate solution with a density of 18 mg / ml and mix it into the above solution. Continue stirring for 35 min. Filter and wash, and redisperse in 15 ml of deionized water.

[0091] Weigh 0.002 mol of cerium chloride, 120 mg of PVP, and formic acid, dissolve them in ethylene glycol, mix them evenly, add urea, and hydrothermally react at 200°C for 36 hours after dissolution. After cooling to room temperature, filter and dry, and calcine at 400°C for 4 hours.

[0092] The solution containing two kinds of precious metals is mixed and impregnated with the carrier sol, and then dried and calcined at 550° C. for 3 hours to obtain the desired catalyst.

[0093] Test method:

[0094] CO catalytic test:

[0095] The experimental device of the interconnected catalyst includes a gas cylinder, a gas pipeline and valve, a temperature and flow control system, a reaction tube, a heating furnace, and a flow meter. The gas cylinder is a standard pressure tank, and the gas enters the pipeline through a valve. After entering the pipeline, the gas passes through the main valve, pressure reducing valve, ball valve, and mass flow meter and enters the mixing device for uniform mixing. The mass flow meter controls the flow value through a computer program. The CO concentration in the gas is 5000ppm, and the concentration at the inlet and outlet of the reaction tube is detected by a CO infrared detector.

[0096] Test on the change of CO catalytic performance under sulfur-containing conditions:

[0097] CO catalytic test was carried out in an environment with a SO2 concentration of 150ppm.

[0098] Test results:

[0099] refer to Figure 1-Figure 3 The carbon monoxide removal catalyst prepared in this example has stable catalytic performance within 12 hours under the test conditions of 160°C-200°C.

[0100] refer to Figure 4 The catalytic performance of the carbon monoxide removal catalyst prepared in this example remained at a relatively stable level within 20 hours under an environment with a SO2 concentration of 150 ppm.

[0101] In the description of this application, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. "First feature" and "second feature" may include one or more of the features.

[0102] In the description of the present application, a first feature being “on” or “under” a second feature may include that the first and second features are directly in contact with each other, or may include that the first and second features are not in direct contact with each other but are in contact with each other via another feature therebetween.

[0103] In the description of the present application, “above”, “over” and “above” a first feature to a second feature includes the first feature being directly above and obliquely above the second feature, or simply means that the first feature is horizontally higher than the second feature.

[0104] In the description of the present application, "A and / or B" may include the case of A alone, the case of B alone, or any of the cases of A and B, where A and B are only used for examples and may be any technical feature connected by "and / or" in the present application.

[0105] In the present application, the writing order of each step does not mean a strict execution order and does not constitute any limitation on the implementation process. The specific execution order of each step should be determined by its function and possible internal logic. If there is no special explanation, all steps of the present application can be performed sequentially or randomly, preferably sequentially. For example, the method includes steps (a) and (b), indicating that the method may include steps (a) and (b) performed sequentially, or may include steps (b) and (a) performed sequentially. For example, the method may also include step (c), indicating that step (c) can be added to the method in any order, for example, the method may include steps (a), (b) and (c), or may include steps (a), (c) and (b), or may include steps (c), (a) and (b), etc.

[0106] It should be noted that the present application is not limited to the above-mentioned embodiments. The above-mentioned embodiments are only examples, and the embodiments having the same structure as the technical idea and exerting the same effect within the scope of the technical solution of the present application are all included in the technical scope of the present application. In addition, without departing from the scope of the main purpose of the present application, various modifications that can be thought of by those skilled in the art to the embodiments and other methods of combining some of the constituent elements in the embodiments are also included in the scope of the present application.

Claims

1. A carbon monoxide removal catalyst, characterized in that: include: A composite substance, the composite substance comprising a first noble metal salt and a second noble metal salt, the first noble metal salt comprising a first noble metal element, the first noble metal element comprising a palladium element and / or a platinum element, the second noble metal salt comprising a second noble metal element, the second noble metal element comprising a ruthenium element and / or a rhodium element, Wherein, in the composite material, the mass ratio of the first noble metal element to the second noble metal element is 1:(0.8-1.6); A shell at least partially covers the outer surface of the composite material, and the shell includes a ceria carrier.

2. The carbon monoxide removal catalyst according to claim 1, characterized in that The Dv50 particle size of the composite material is 5nm-15nm; and / or, The thickness of the shell is 15nm-25nm.

3. A method for preparing the carbon monoxide removal catalyst according to claim 1 or 2, characterized in that: include: The first noble metal salt solution and the auxiliary agent aqueous solution are mixed and heated in a volume ratio of 1:(0.5-5) to obtain a first noble metal salt precursor; The alcohol solution of the first noble metal salt precursor and the alcohol solution of the auxiliary agent are mixed in a volume ratio of 1:(3-6) to obtain a first noble metal salt precursor solution; The complexing agent and the second noble metal salt solution are mixed and then added to the first noble metal salt precursor solution, and heated to obtain a composite material, wherein the adding speed is 0.5 mL / min-1.5 mL / min; The demulsifier, the cerium dioxide carrier sol and the composite material aqueous solution are mixed to obtain a carbon monoxide removal catalyst. The cerium dioxide carrier sol comprises a cerium dioxide carrier and an alcohol solvent, the concentration of the composite substance aqueous solution is 10 mg / mL-30 mg / mL, and the volume ratio of the cerium dioxide carrier sol to the composite substance aqueous solution is (1-1.5):

1.

4. The method according to claim 3, characterized in that The first noble metal salt comprises at least one of tetraammine palladium oxalate, sodium palladate, chloropalladic acid, chloroplatinic acid, and potassium hexachloroplatinate; and / or, The mass density of the first noble metal salt solution is 10 mg / mL-20 mg / mL; and / or, The auxiliary agent aqueous solution comprises a surfactant, a reducing agent, a capping agent, and deionized water, wherein the mass ratio of the surfactant, the reducing agent, the capping agent, and the deionized water is 1:(0.4-1):(1.6-5):(6.5-8); and / or, The temperature of the mixed heating treatment is 60° C.-90° C., and the time of the mixed heating is 20 min-60 min.

5. The method according to claim 3, characterized in that: The alcohol solution of the first noble metal salt precursor comprises the first noble metal salt precursor and an alcohol solvent, and the concentration of the alcohol solution of the first noble metal salt precursor is 15 mg / mL-30 mg / mL; and / or, The auxiliary alcohol solution comprises a surfactant, a reducing agent, and an alcohol solvent, wherein the volume ratio of the surfactant, the reducing agent, and the alcohol solvent is 1:(0.3-1.5):(50-100); and / or, The mass fraction of the first noble metal salt precursor solution is 10 mg / mL-20 mg / mL.

6. The method according to claim 3, characterized in that The second noble metal salt solution comprises a second noble metal salt, a surfactant, and an alcohol solvent, wherein the ratio of the mass of the second noble metal salt, the mass of the surfactant, and the volume of the alcohol solvent is 1:(100-150):(10-30); and / or, The second precious metal salt includes at least one of a ruthenium metal salt and a rhodium metal salt, wherein the ruthenium metal salt includes at least one of ruthenium trichloride and ruthenium acetate, and the rhodium metal salt includes at least one of rhodium chloride and rhodium nitrate; and / or, The molar ratio of the complexing agent, the second noble metal salt in the second noble metal salt solution and the first noble metal salt in the first noble metal salt solution is 1:(1.5-3).

7. The method according to claim 3, characterized in that The demulsifier comprises at least one of potassium chloride and sodium chloride; and / or, The ceria carrier sol comprises a ceria carrier and an alcohol solvent, wherein the mass ratio of the demulsifier to the ceria carrier is 1:(0.5-1.5), and the mass volume ratio of the ceria carrier to the alcohol solvent is 1:(5-20).

8. The method according to any one of claims 3 to 7, characterized in that: The alcohol solvent includes at least one of ethylene glycol, polyethylene glycol 200, diethylene glycol, and tetraethylene glycol; and / or, The complexing agent includes at least one of citric acid monohydrate, oxalic acid, ethylenediaminetetraacetic acid, and glucose.

9. The method according to any one of claims 4 to 6, characterized in that: The surfactant includes at least one of polyvinyl pyrrolidone, octadecylamine, polyethylene oxide-polypropylene oxide-polyethylene oxide triblock copolymer, ethylene glycol dimethyl ether, dimethyl sulfoxide, N,N-dimethylformamide, N-methylpyrrolidone, hexadecyltrimethylammonium bromide, and tetrabutylammonium bromide.

10. A method for preparing the cerium dioxide carrier sol according to claims 3-9, characterized in that: include: The cerium source, the surfactant, the co-solvent, the end-capping agent, the precipitant, and the mineralizer are subjected to hydrothermal treatment to obtain the cerium dioxide mixture, wherein the mass ratio of the cerium source, the surfactant, the co-solvent, the end-capping agent, the precipitant, and the mineralizer is 1:(3-5):(0.5-2):(0.3-0.8):(1-3):(0.1-0.9); The cerium dioxide mixture is calcined to obtain a cerium dioxide carrier; wherein: The temperature of the hydrothermal treatment is 150°C-200°C, the time of the hydrothermal treatment is 12h-48h, the temperature of the calcination treatment is 250°C-350°C, and the time of the calcination treatment is 2h-6h; The ceria carrier sol is obtained by subjecting the ceria carrier and the alcohol solvent to ultrasonic treatment.

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