Preparation methods, catalysts and applications of monolithic catalysts for CO catalytic oxidation

Abstract

This invention discloses a method for preparing a monolithic catalyst for CO catalytic oxidation, the catalyst itself, and its applications. The method includes: S1. Core-shell promoter preparation: TiO2 nanoparticles are provided, and a hydroxide precursor containing Sb and Sn is coated on their surface using a co-precipitation method. After drying and calcination, a TiO2-Sb-SnO2 composite powder with a core-shell structure is obtained; S2. Promoter layer coating: The composite powder obtained in step S1 is mixed with a binder and a solvent to form a slurry, which is then coated onto the surface of a honeycomb ceramic carrier. After drying and calcination, a composite promoter layer is formed; S3. Active component loading: The carrier with the composite promoter layer obtained in step S2 is immersed in a noble metal precursor solution. After drying, it is subjected to thermal shock treatment, so that the noble metal is loaded onto the surface of the composite promoter layer in the form of nanoparticles. The catalyst of this invention achieves nearly 100% CO conversion and maintains excellent stability for more than 100 hours.

Description

Technical Field

[0001] This invention relates to the field of flue gas purification technology in the iron and steel industry, specifically to a method for preparing a monolithic catalyst for CO catalytic oxidation, the catalyst itself, and its applications. Background Technology

[0002] CO is one of the main air pollutants emitted by industries such as steel, coking, and power generation. End-of-pipe treatment technologies, with catalytic oxidation as their core, are effective means of CO removal. Among these, noble metal catalysts are widely used due to their abundant active sites and high electron transport rates. However, industrial flue gas has a complex composition, especially the ubiquitous presence of SO2 and H2O. SO2 can compete with the active sites of the catalyst, adsorbing onto the catalyst surface and forming sulfuric acid or sulfates, which can cover the active sites and even block the carrier pores, leading to permanent catalyst deactivation. H2O, on the other hand, competes with the reactants CO and O2 for adsorption, inhibiting the reaction. Therefore, developing a CO oxidation catalyst that can maintain high activity and long lifespan under sulfur- and water-containing conditions is currently a major technological challenge in this field. Summary of the Invention

[0003] In view of the above problems, the present invention is proposed to provide a method for preparing a monolithic catalyst for CO catalytic oxidation, the catalyst, and its application, which overcomes or at least partially solves the above problems.

[0004] A method for preparing a monolithic catalyst for CO catalytic oxidation according to an embodiment of the present invention includes the following steps: S1. Preparation of core-shell additives: TiO2 nanoparticles are provided, and Sb and Sn hydroxide precursors are coated on their surface by co-precipitation. After drying and calcination, TiO2-Sb-SnO2 composite powder with core-shell structure is obtained. S2. Coating of the additive layer: The composite powder obtained in step S1 is mixed with binder and solvent to form a slurry, which is then coated on the surface of the honeycomb ceramic carrier and dried and calcined to form a composite additive layer; S3. Loading of active components: The carrier loaded with the composite additive layer obtained in step S2 is immersed in a noble metal precursor solution, taken out and dried, and then subjected to thermal shock treatment so that the noble metal is loaded on the surface of the composite additive layer in the form of nanoparticles.

[0005] In some embodiments, the preparation method of the TiO2 nanoparticles in step S1 includes: mixing K2CO3 with metatitanic acid in a molar ratio of 1:(2-3), drying, grinding, and calcining to obtain potassium tetratitanate, and then subjecting it to water boiling, acid boiling, filtration, drying, grinding, filtration, and secondary calcination treatment.

[0006] In some implementations, in step S1, the molar ratio of Sn to Sb is (4-7):1.

[0007] In some embodiments, in step S2, the binder is silica sol or aluminum sol; the calcination temperature is 500-600°C, and the time is 2-6 hours.

[0008] In some embodiments, in step S3, the noble metal precursor is chloroplatinic acid or platinum nitrate, and the total noble metal loading is 0.1-0.3 wt% of the total mass of the catalyst.

[0009] In some implementations, in step S3, the thermal shock treatment is achieved by capacitor discharge, with an input power of 150-400W and a single pulse duration of 15-100ms.

[0010] According to another embodiment of the present invention, a monolithic catalyst for sulfur- and water-resistant CO catalytic oxidation prepared according to any one of the above-described preparation methods is provided, comprising: Honeycomb ceramic carrier; A composite additive layer coated on the surface of the carrier, the composite additive layer comprising a TiO2-Sb-SnO2 composite oxide with a core-shell structure; Noble metal nanoparticles loaded on the surface of the composite additive layer; The TiO2-Sb-SnO2 composite oxide has a regular structure with TiO2 as the core and Sb-doped SnO2 as the shell.

[0011] In some embodiments, the cellular ceramic carrier is one or more of cordierite, mullite, and corundum.

[0012] In some embodiments, the mass percentage of TiO2-Sb-SnO2 composite oxide in the composite additive layer is 10%-30%.

[0013] According to another aspect of the present invention, an application of the catalyst according to any one of the above claims in purifying sulfur- and water-containing industrial flue gas is provided, wherein the industrial flue gas comprises at least one of the following: CO concentration of 500-20000 ppm, SO2 concentration of 50-300 mg / m³. 3 The volume content of H2O is 10%-20%, and the temperature is 100-400℃. Compared with the prior art, the embodiments of the present invention can achieve the following beneficial effects: (1) Synergistic anti-sulfur and anti-water mechanism: The TiO2@Sb-SnO2 composite additive layer provided in this invention is the key. The Sb-SnO2 shell provides good conductivity and suitable surface acidity, which can both promote electron transfer and selectively inhibit the strong adsorption of SO2, effectively avoiding the poisoning of noble metal active sites by SO2 and H2O molecules. At the same time, TiO2 nanoparticles, as a pre-synthesized core, can effectively adsorb and activate CO, ensuring high CO catalytic efficiency.

[0014] (2) High dispersion and stability of active sites: High-temperature thermal shock, an unconventional preparation technique, is used to replace the traditional slow calcination. At the same time, a conductive core-shell auxiliary layer is constructed. The combination of the two enables the loading process of noble metal to complete the precursor decomposition and shaping instantly, which greatly inhibits the migration and sintering of noble metal particles, thereby obtaining smaller and more uniformly distributed nano-active sites, improving the utilization rate of noble metal and the intrinsic catalytic activity.

[0015] (3) Simple and controllable process: The entire preparation process does not require complex equipment or harsh conditions. The three-step process of pre-synthesis, coating and thermal shock is clear, the parameters are easy to control, and the reproducibility is good, making it very suitable for industrial scale-up production.

[0016] (4) Excellent overall performance: The catalyst of this invention performs well under simulated harsh flue gas conditions (such as CO concentration of 15000ppm and SO2 concentration of 100mg / m³). 3 H2O content 15 vol%, space velocity 20000 h⁻¹ -1 At 200-250℃, CO can be completely converted, and its activity does not decrease after more than 100 hours of continuous operation, demonstrating excellent stability and practical application potential. Attached Figure Description

[0017] Figure 1 This is a schematic flowchart of the preparation method of the monolithic catalyst for CO catalytic oxidation provided by the present invention; Figure 2 This is a CO conversion graph of Test Example 1 provided by the present invention; Figure 3 This is a CO conversion graph of Test Example 2 provided by the present invention; Figure 4 This is a CO conversion graph of Test Example 3 provided by the present invention; Figure 5 This is a graph showing the CO conversion rate of Test Example 4 provided by the present invention; Figure 6 This is a graph showing the CO conversion rate from the catalyst activity test in Example 1 provided by the present invention; Figure 7 This is a graph showing the CO conversion rate from the catalyst stability test in Example 1 provided by the present invention; Figure 8This is a physical image of the catalyst provided by the present invention. Detailed Implementation

[0018] Numerous specific details are set forth in the following description to provide a full understanding of the invention. However, the invention can be practiced in many other ways different from those described herein, and those skilled in the art can make similar extensions without departing from the spirit of the invention. Therefore, the invention is not limited to the specific embodiments disclosed below.

[0019] It should be understood that the terminology used in this invention is merely for describing particular embodiments and is not intended to limit the invention. Furthermore, regarding numerical ranges in this invention, it should be understood that each intermediate value between the upper and lower limits of the range is also specifically disclosed. Every smaller range between any stated value or intermediate value within a stated range, and any other stated value or intermediate value within said range, is also included within the scope of this invention. The upper and lower limits of these smaller ranges may be independently included. Unless otherwise stated, all technical and scientific terms used in this invention have the same meaning as commonly understood by one of ordinary skill in the art. While only preferred methods and materials have been described in this invention, any methods and materials similar to or equivalent to those described herein may be used in the practice or testing of this invention.

[0020] Various modifications and variations can be made to the specific embodiments described in this specification without departing from the scope or spirit of the invention, as will be apparent to those skilled in the art. Other embodiments derived from this specification will be obvious to those skilled in the art, and the specification and embodiments are merely exemplary.

[0021] The terms “comprising,” “including,” “having,” “containing,” etc., used in this invention are all open-ended terms, meaning that they include but are not limited to.

[0022] In the description of this invention, references to terms such as "one embodiment," "some embodiments," "illustrative embodiment," "example," "specific example," or "some examples," etc., refer to specific features, structures, materials, or characteristics described in connection with that embodiment or example, which are included in at least one embodiment or example of this invention.

[0023] The method for preparing a monolithic catalyst for CO catalytic oxidation according to one aspect of the present invention has sulfur and water resistance functions, combined with Figure 1 As shown, it includes the following steps: 1) Pre-synthesized TiO2 nanoparticles: A chemical synthesis method was used. A certain amount of K2CO3 and metatitanic acid were dispersed in deionized water and stirred until homogeneous. After drying, grinding, sieving, and calcination, potassium tetratitanate nanomaterials were obtained. The potassium tetratitanate sample was ground and sieved, then boiled first in deionized water, then boiled again in HCl, filtered, and dried to obtain tetratitanic acid nanomaterials. After further grinding, sieving, and calcination, TiO2 nanoparticles were obtained. 2) Pre-synthesis of TiO2@Sb-SnO2 core-shell structured nanoparticles: The TiO2 nanoparticles obtained in step 0) are used as the core, and Sb-Sn hydroxide is coated on the surface by co-precipitation. SnCl4·5H2O and SbCl3 are used as precursor sources, mixed with a cosolvent and a neutralizing agent, and TiO2@Sb-SnO2 precursor is prepared after co-precipitation reaction. After drying and calcination, TiO2@Sb-SnO2 nanoparticles with a regular core-shell structure are obtained. 3) Preparation of slurry and coating: The TiO2@Sb-SnO2 nanopowder obtained in step 1), binder and solvent are mixed and ball-milled to form a uniform slurry. The slurry is then coated on the surface of the honeycomb ceramic carrier. After drying and calcination, a firm TiO2@Sb-SnO2 composite additive layer is formed. 4) High-temperature thermal shock loading of noble metals: The carrier with the additive layer obtained in step 3) is immersed in a noble metal precursor solution, taken out and dried, and then subjected to high-temperature thermal shock treatment to load the noble metal on the surface of the additive layer in the form of nanoparticles, thus obtaining the monolithic catalyst.

[0024] In some embodiments, in step 1), the TiO2 nanoparticles are prepared by a hydrothermal method, wherein the molar ratio of K2CO3:TiO2 is 1:(2-3), preferably 1:2.

[0025] In some embodiments, in step 1), the calcination temperature is 500-600℃ and the calcination time is 3-5h.

[0026] In some embodiments, during step 2), when the Sb-Sn hydroxide is co-precipitated and coated, the molar ratio of SnCl4·5H2O to SbCl3 is (4-7):1, preferably 5:1; and the loading of Sn is 15wt% relative to TiO2.

[0027] In some embodiments, in step 2), the calcination temperature is 500-600℃ and the calcination time is 3-5h.

[0028] In some embodiments, in step 2), the co-solvent is 3 mol / L dilute hydrochloric acid, and the neutralizing agent is 7.5 mol / L ammonia solution.

[0029] In some embodiments, in step 3), the binder is silica sol or aluminum sol; the mass percentage of TiO2@Sb-SnO2 nanoparticles in the slurry is 10%-30%.

[0030] In some embodiments, in step 3), the honeycomb ceramic carrier is one or more of cordierite, mullite, and corundum, preferably cordierite.

[0031] In some embodiments, in step 3), the coating method is an equal-volume impregnation method; the calcination temperature after coating is 500-600℃, and the calcination time is 2-6 hours.

[0032] In some embodiments, in step 4), the noble metal precursor is one of chloroplatinic acid and platinum nitrate, preferably platinum nitrate.

[0033] In some embodiments, the total loading of the noble metal active component in step 4) is 0.2 wt% of the catalyst mass.

[0034] In some embodiments, in step 4), the high-temperature thermal shock treatment is achieved by capacitor discharge, with an input power of 150-400W and an impact duration of 15-100ms.

[0035] This invention also includes the application of the above-mentioned catalyst in purifying carbon monoxide in sintering flue gas, coke oven gas, or industrial boiler flue gas, wherein the flue gas conditions include, but are not limited to: CO concentration 500-20000 ppm, SO2 concentration 50-300 mg / m³. 3 H2O content 10%-20%, temperature 100-400℃.

[0036] To enable those skilled in the art to better understand the technical solution of this invention, the following description is provided in conjunction with the appendix. Figure 2-8 The present invention will be further described in detail below with reference to the preferred embodiments.

[0037] Example 1: A monolithic catalyst for sulfur- and water-resistant CO catalytic oxidation synthesized based on high-temperature thermal shock and its preparation method thereof specifically include the following steps: 1) Carrier pretreatment: Soak 200-mesh cordierite honeycomb ceramic (size: 10cm×10cm×5cm) in 5% dilute nitric acid for 2 hours, rinse with deionized water until neutral, and dry at 110℃ for 3 hours.

[0038] 2) Pre-synthesized TiO2 nanoparticles: A certain amount of K2CO3 and metatitanic acid were dispersed in deionized water at a K2CO3:TiO2 molar ratio of 1:2 and stirred until homogeneous. After drying, grinding, and passing through a 60-mesh sieve, the mixture was calcined at 600℃ for 4 hours in a muffle furnace to obtain potassium tetratitanate nanomaterials. The potassium tetratitanate sample was ground and passed through a 60-mesh sieve, then boiled in deionized water for 6 hours. After filtration and washing, the sample was boiled again in 2 mol / L HCl for 6 hours, filtered, and dried to obtain tetratitanic acid nanoparticles. These were then ground again, passed through a 60-mesh sieve, and calcined at 550℃ for 4 hours to obtain TiO2 nanoparticles. 3) Pre-synthesis of TiO2@Sb-SnO2 powder: 10g of TiO2 nanoparticles were dispersed in 200mL of deionized water to prepare a TiO2 suspension. The suspension was dissolved in 50mL of dilute hydrochloric acid (3mol / L) at a SnCl4·5H2O:SbCl3 molar ratio of 5:1 to obtain solution A. Under vigorous stirring in an 80℃ water bath, solution A and an ammonia solution (7.5mol / L, used to maintain pH≈7) were simultaneously added dropwise to the TiO2 suspension at a rate of 1mL / min. After the addition was complete, the reaction continued for 2 hours. The mixture was then filtered, washed, dried, and finally calcined in a muffle furnace at 550℃ for 4 hours to obtain the TiO2@Sb-SnO2 composite powder.

[0039] 4) Coating the additive layer: Mix the above powder with silica sol (binder) at a mass ratio of 4:1, add deionized water and ball mill for 6 hours to prepare a uniform slurry with a solid content of 20%. Apply the slurry to the pretreated cordierite carrier by impregnation, dry at 110°C, and then calcine in air at 550°C for 4 hours to form a strong additive layer.

[0040] 5) High-temperature thermal shock loading of Pt: Platinum nitrate solution was used, and the target loading of Pt was controlled at 0.2 wt% (relative to the total catalyst mass). The support was impregnated in the platinum salt solution using an equal-volume impregnation method, and then dried at room temperature. The dried sample was placed in a high-temperature thermal shock apparatus, and a pulsed current of 300 W was applied under a nitrogen atmosphere for 50 milliseconds to instantly complete the loading and reduction of the Pt precursor, resulting in the final catalyst denoted as Pt / ZJ-1@CHC-HTS (ZJ: promoter layer, CHC: cordierite support, HTS: high-temperature thermal shock).

[0041] Example 2: A monolithic catalyst for sulfur- and water-resistant CO catalytic oxidation synthesized based on high-temperature thermal shock and its preparation method are disclosed. The basic synthesis steps are the same as those in Example 1. The difference is that in step 2), the molar ratio of K2CO3:TiO2 is added at 1:3. The rest is the same as in Example 1. The resulting catalyst is denoted as Pt / ZJ-2@CHC-HTS.

[0042] Example 3: A monolithic catalyst for the catalytic oxidation of sulfur and water resistant CO based on high-temperature thermal shock synthesis and its preparation method are disclosed. The basic synthesis steps are the same as those in Example 1. The difference is that in step 3), SnCl4·5H2O:SbCl3 is added at a molar ratio of 4:1. The rest is the same as in Example 1. The resulting catalyst is denoted as Pt / ZJ-3@CHC-HTS.

[0043] Example 4: A monolithic catalyst for the catalytic oxidation of sulfur and water resistant CO based on high-temperature thermal shock synthesis and its preparation method are disclosed. The basic synthesis steps are the same as those in Example 1. The difference is that in step 3), SnCl4·5H2O:SbCl3 is added at a molar ratio of 6:1. The rest is the same as in Example 1. The resulting catalyst is denoted as Pt / ZJ-4@CHC-HTS.

[0044] Example 5: A monolithic catalyst for sulfur- and water-resistant CO catalytic oxidation synthesized based on high-temperature thermal shock and its preparation method are disclosed. The basic synthesis steps are the same as those in Example 1. The difference is that in step 3), SnCl4·5H2O:SbCl3 is added at a molar ratio of 7:1. The rest is the same as in Example 1. The resulting catalyst is denoted as Pt / ZJ-5@CHC-HTS.

[0045] Comparative Example 1: A monolithic catalyst for the catalytic oxidation of sulfur and water based on high-temperature thermal shock synthesis and its preparation method are disclosed. The basic synthesis steps are the same as those in Example 1. The difference is that in step 1), mullite is used as the support. The rest is the same as in Example 1. The resulting catalyst is denoted as Pt / ZJ@M-HTS.

[0046] Comparative Example 2: A monolithic catalyst for sulfur- and water-resistant CO catalytic oxidation synthesized based on high-temperature thermal shock and its preparation method are disclosed. The basic synthesis steps are the same as those in Example 1. The difference is that in step 1), corundum is used as the support. The rest is the same as in Example 1. The resulting catalyst is denoted as Pt / ZJ@G-HTS.

[0047] Comparative Example 3: A monolithic catalyst for sulfur- and water-resistant CO catalytic oxidation synthesized based on high-temperature thermal shock and its preparation method are disclosed. The basic synthesis steps are the same as those in Example 1. The difference is that steps 2), 3), and 4) are omitted, and the Pt active component is directly loaded by high-temperature thermal shock. The rest is the same as in Example 1. The resulting catalyst is denoted as Pt@CHC-HTS.

[0048] Comparative Example 4: A monolithic catalyst for sulfur and water resistant CO catalytic oxidation synthesized based on high-temperature thermal shock and its preparation method are disclosed. The basic synthesis steps are the same as those in Example 1. The difference is that in step 5), the precursor of Pt is chloroplatinic acid. The rest is the same as in Example 1. The resulting catalyst is denoted as Pt-1 / ZJ@CHC-HTS.

[0049] Comparative Example 5: A monolithic catalyst for the catalytic oxidation of sulfur and water resistant CO, synthesized based on high-temperature thermal shock, and its preparation method are disclosed. The basic synthesis steps are the same as in Example 1, except that in step 5), the support with the promoter layer is immersed in a noble metal precursor solution, dried, and then directly calcined in a muffle furnace at 550°C for 4 hours to obtain the final catalyst. Other steps are the same as in Example 1. The obtained catalyst is designated as Pt / ZJ@CHC-DS.

[0050] It should be noted that the comparative examples in this application are only for ease of comparison and are still part of the embodiments, and are within the protection scope of this application.

[0051] Test Example 1: The prepared examples and comparative catalysts were subjected to a fixed-bed reaction with CO concentration of 15,000 ppm, O2 concentration of 12 vol%, N2 as balance gas, and gas space velocity of 20,000 h⁻¹. -1 Reaction temperature: 200℃.

[0052] Test Example 2: The prepared examples and comparative catalysts were subjected to a fixed-bed reaction with CO gas concentration of 15000 ppm and SO2 gas concentration of 150 mg / m³. 3 O2 concentration: 12 vol%, N2: balance gas, gas space velocity: 20000 h⁻¹ -1 Reaction temperature: 200℃.

[0053] Test Example 3: The prepared examples and comparative catalysts were subjected to a fixed-bed reaction with CO gas concentration of 15000 ppm, O2 concentration of 12 vol.%, H2O content of 15 vol%, N2 as balance gas, and gas space velocity of 20000 h⁻¹. -1 Reaction temperature: 200℃.

[0054] Test Example 4: The prepared examples and comparative catalysts were subjected to a fixed-bed reaction with CO gas concentration of 15000 ppm and SO2 gas concentration of 150 mg / m³. 3 O2 concentration: 12 vol%, H2O content: 15%, N2: balance gas, gas space velocity: 20000 h⁻¹ -1 Reaction temperature: 200℃.

[0055] Catalyst activity was tested under the conditions of Test Example 1, Test Example 2, Test Example 3, and Test Example 4. The test results for CO are shown in Table 1. Figure 1 , Figure 2 , Figure 3 and Figure 4 As shown; Table 1. Summary of CO conversion rate data for test cases (%) The key role of the TiO2@Sb-SnO2 composite additive layer: 1) Providing high specific surface area and stable anchoring points: As shown in the activity performance data of Comparative Example 3, its catalytic activity is extremely low. This fully demonstrates that the unmodified cordierite support, due to its small specific surface area, cannot effectively disperse and fix the active centers of noble metals. However, the pre-fabricated TiO2@Sb-SnO2 composite additive layer of this invention successfully constructs a microscopic nano-active interface with a high specific surface area on the macroscopic cordierite support. Simultaneously, its excellent conductivity provides a solid foundation for the subsequent high dispersion of Pt nanoparticles.

[0056] 2) Imparting intrinsic electrical conductivity and sulfur resistance to the catalyst: Conductivity: Experimental data from Examples 1-5 show that Sb doping significantly improves the conductivity of the additive layer, which is crucial for forming a uniform Joule thermal field and achieving instantaneous uniform dispersion of the Pt precursor during the HTS process. The most preferred Example 1 has a stable CO conversion efficiency of 100%.

[0057] Sulfur resistance: In Test Examples 2 and 4 containing SO2, all examples containing the composite additive layer (Examples 1-5) exhibited significantly higher stability than Comparative Example 3. This demonstrates that the surface acidity of the composite additive layer can selectively inhibit the strong adsorption of SO2 molecules at the active sites, fundamentally blocking the sulfur poisoning pathway and thus improving the sulfur resistance of the catalyst.

[0058] The decisive significance of high-temperature thermal shock (HTS) technology: High-temperature thermal shock (HTS) technology is a core process for achieving high dispersion and stability of active sites in noble metals, with significance far exceeding traditional heat treatment methods. Achieving ultra-high dispersion of noble metal nanoparticles, the performance comparison between Comparative Example 5 and Example 1 demonstrates that, even with the same excellent additive layer, the catalyst prepared by the traditional calcination method exhibits severely insufficient activity and stability. Fundamentally, the extremely high heating and cooling rates of HTS technology significantly suppress the surface migration and aggregation of Pt atoms, resulting in smaller and more uniformly distributed Pt nanoparticles. This not only greatly improves the atomic utilization rate of noble metals but also significantly enhances intrinsic catalytic activity.

[0059] In summary, the combination of the composite additive layer and high-temperature thermal shock (HTS) technology produces an excellent synergistic effect. The additive layer provides an ideal conductive substrate for the HTS process, ensuring the uniformity and efficiency of thermal shock; while the HTS technology maximizes the structural advantages of the additive layer, uniformly loading Pt onto the support surface in the optimal form, thus enhancing the intrinsic activity of the catalyst while providing superior sulfur and water resistance.

[0060] Compared with the prior art, the beneficial effects and outstanding advantages of the present invention are as follows: 1) The innovative design concept of “conductive additive layer + high temperature thermal shock” was proposed: by first constructing a core-shell structure additive layer with high specific surface area, excellent conductivity and specific surface acidity on cordierite carrier, and then using high temperature thermal shock technology to instantaneously load Pt active components, the industry problem of high dispersion and anti-poisoning performance of precious metals can be solved at the same time.

[0061] 2) Excellent catalytic performance: The prepared catalyst exhibits a CO conversion rate of nearly 100% and an ultra-long stability of more than 100 hours under simulated harsh flue gas conditions (containing high concentrations of SO2 and H2O), with comprehensive performance far exceeding that of catalysts prepared by the traditional impregnation-calcination method.

[0062] 3) Advanced and controllable preparation process: The high-temperature thermal shock process is completed instantaneously, with low energy consumption and no need for complex equipment. Moreover, the parameters of the entire preparation process are easy to control and have good reproducibility, laying a solid foundation for industrial-scale production.

[0063] 4) Broad application prospects: The catalyst of this invention is not only applicable to CO purification of sintering flue gas in iron and steel, but its core sulfur and water resistant design strategy also provides new ideas and technical paths for the development of catalysts for treating sulfur-containing and water-containing motor vehicle exhaust gas, chemical process waste gas and other fields.

[0064] It should be noted that although the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make possible changes and modifications without departing from the spirit and scope of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope defined in the claims of the present invention.

Claims

1. A method for preparing a monolithic catalyst for CO catalytic oxidation, characterized in that, Includes the following steps: S1. Preparation of core-shell additives: TiO2 nanoparticles are provided, and Sb and Sn hydroxide precursors are coated on their surface by co-precipitation. After drying and calcination, TiO2-Sb-SnO2 composite powder with core-shell structure is obtained. S2. Coating of the additive layer: The composite powder obtained in step S1 is mixed with binder and solvent to form a slurry, which is then coated on the surface of the honeycomb ceramic carrier and dried and calcined to form a composite additive layer; S3. Loading of active components: The carrier loaded with the composite additive layer obtained in step S2 is immersed in a noble metal precursor solution, taken out and dried, and then subjected to thermal shock treatment so that the noble metal is loaded on the surface of the composite additive layer in the form of nanoparticles.

2. The preparation method according to claim 1, characterized in that, In step S1, the method for preparing the TiO2 nanoparticles includes: mixing K2CO3 with metatitanic acid in a molar ratio of 1:(2-3), drying, grinding, and calcining to obtain potassium tetratitanate, and then subjecting it to water boiling, acid boiling, filtration, drying, grinding, filtration, and secondary calcination treatment to obtain the final product.

3. The preparation method according to claim 1, characterized in that, In step S1, the molar ratio of Sn to Sb is (4-7):

1.

4. The preparation method according to claim 1, characterized in that, In step S2, the binder is silica sol or aluminum sol; the calcination temperature is 500-600℃ and the time is 2-6 hours.

5. The preparation method according to claim 1, characterized in that: In step S3, the noble metal precursor is chloroplatinic acid or platinum nitrate, and the total loading of noble metal is 0.1-0.3 wt% of the total mass of the catalyst.

6. The preparation method according to claim 1, characterized in that, In step S3, the thermal shock treatment is achieved by capacitor discharge, with an input power of 150-400W and a single pulse duration of 15-100ms.

7. A monolithic catalyst for sulfur- and water-resistant CO catalytic oxidation prepared by the method according to any one of claims 1-6, characterized in that, include: Honeycomb ceramic carrier; A composite additive layer coated on the surface of the carrier, the composite additive layer comprising a TiO2-Sb-SnO2 composite oxide with a core-shell structure; Noble metal nanoparticles loaded on the surface of the composite additive layer; The TiO2-Sb-SnO2 composite oxide has a regular structure with TiO2 as the core and Sb-doped SnO2 as the shell.

8. The catalyst according to claim 7, characterized in that, The honeycomb ceramic carrier is one or more of cordierite, mullite, and corundum.

9. The catalyst according to claim 7 or 8, characterized in that, In the composite additive layer, the mass percentage of TiO2-Sb-SnO2 composite oxide is 10%-30%.

10. The application of the catalyst according to any one of claims 7-9 in purifying sulfur- and water-containing industrial flue gas, characterized in that, The industrial flue gas contains at least one of the following: CO concentration of 500-20000 ppm, SO2 concentration of 50-300 mg / m³. 3 The volume content of H2O is 10%-20%, and the temperature is 100-400℃.

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