Chlorine-poisoning-resistant co oxidation catalyst, and preparation method and application thereof

Abstract

This invention discloses a chlorine-poison-resistant CO oxidation catalyst, its preparation method, and its application, belonging to the field of catalyst technology. The chlorine-poison-resistant CO oxidation catalyst of this invention comprises anatase TiO2 support and active components supported on the support; wherein the active components include Pt, Pd, and Ru. The chlorine-poison-resistant CO oxidation catalyst of this invention achieves a space velocity of 60,000 h⁻¹. ‑1 CO concentration 10000 mg / m³ 3 Under harsh conditions containing 200 ppm HCl or 200 ppm chlorobenzene, complete CO conversion can be achieved at 165 °C, and the catalyst activity retention rate is >95% after 100 h of reaction.

Description

Technical Field

[0001] This invention relates to the field of catalyst technology, and in particular to a CO oxidation catalyst resistant to chlorine poisoning, its preparation method, and its application. Background Technology

[0002] With the rapid development of modern industry, the synergistic emission of chlorinated volatile organic compounds (CVOCs) and carbon monoxide (CO) has become a key challenge in air pollution control. For example, waste gases generated from high-temperature processes such as waste incineration, steel sintering, chemical synthesis (e.g., pesticide and pharmaceutical intermediate production), and waste pyrolysis not only contain large amounts of CO but also often contain high concentrations of hydrogen chloride (HCl) gas and chlorinated organic compounds such as chlorobenzene and dioxins. CO, as a typical air pollutant, not only harms human health but is also a precursor to photochemical smog; the presence of chlorinated organic compounds greatly increases the difficulty of purification. Currently, catalytic oxidation is considered the most effective means of removing CO from exhaust gases due to its low energy consumption and high efficiency. However, in actual operating conditions, the composition of exhaust gases is extremely complex, especially the presence of chlorine, which easily leads to irreversible deactivation of the catalyst, becoming the biggest bottleneck restricting the industrial application of this technology.

[0003] Existing commercial CO oxidation catalysts mainly utilize noble metals such as platinum (Pt) and palladium (Pd) supported on alumina (Al2O3) or titanium dioxide (TiO2) supports, achieving excellent low-temperature activity. However, these catalysts are highly susceptible to deactivation in chlorine-containing atmospheres. The deactivation mechanisms primarily involve two aspects: first, chemical poisoning, where chlorine free radicals generated from the decomposition of HCl or chlorobenzene in the gas phase undergo strong chemisorption with active sites, occupying the active centers and forming stable metal chlorides (such as Pt-Cl bonds), leading to the permanent loss of active sites; second, carbon deposition and blockage, where chlorobenzene macromolecules are difficult to completely oxidize on the catalyst surface, easily forming viscous polymers or carbon deposits that cover the catalyst pore surface, hindering reactant diffusion. Although researchers have attempted to alleviate chlorine poisoning by doping with rare earth elements or adjusting the acidity / alkalinity of the support, these efforts often have unintended consequences. For example, simply increasing the basicity of the support can neutralize HCl, but it leads to a significant decrease in CO oxidation activity and fails to address the accumulation of chlorine species generated from chlorobenzene cracking at active sites, making it difficult to meet the requirements for long-term stable operation in industrial applications.

[0004] To address the aforementioned technical shortcomings, the development of novel catalysts possessing both high activity and superior chlorine resistance has become a research hotspot in this field. In existing technologies, bimetallic or multimetallic synergistic catalytic systems have been widely explored to enhance catalyst resistance to poisoning due to their ability to generate electronic and geometric effects. However, traditional bimetallic systems (such as Pt-Pd) still exhibit significant limitations when facing high concentrations and diverse forms of chlorine species (the coexistence of HCl and chlorobenzene): while the Pd component can adsorb chlorine, it lacks the ability to convert it; and although the Pt component has high activity, it is extremely sensitive to chlorine. Therefore, there is an urgent need to develop a catalyst that can still exhibit excellent catalytic activity and stability when facing high concentrations and diverse forms of chlorine species (the coexistence of HCl and chlorobenzene). Summary of the Invention

[0005] The purpose of this invention is to provide a CO oxidation catalyst resistant to chlorine poisoning, its preparation method, and its application, so as to solve the problems existing in the prior art.

[0006] To achieve the above objectives, the present invention provides the following solution: One of the technical solutions of the present invention is a CO oxidation catalyst resistant to chlorine poisoning, comprising anatase TiO2 support and an active component supported on the support; The active components include Pt, Pd, and Ru, which are highly dispersed on the surface of the support in a three-component mixed single-atom form.

[0007] In this invention, the anatase TiO2 support serves as the catalyst support framework, and three active components (Pt, Pd, and Ru) are loaded on the surface of the anatase TiO2 support for catalytic oxidation of CO and resistance to chlorine poisoning.

[0008] The CO oxidation catalyst for chlorine poisoning resistance in this invention uses a titanium-based support as a highly stable framework and possesses a Pt-Pd-Ru synergistic active center. Utilizing the electronic complementary effect of these three noble metals, it fundamentally solves the problem of easy chlorination and deactivation of a single noble metal in a chlorine-containing atmosphere. Specifically, Pt acts as the main active center responsible for efficient CO adsorption and oxidation, Pd acts as a chlorine capture center responsible for dissociating chlorine species (HCl and C-Cl bonds), and Ru acts as an electron regulation center to adjust the surface electron cloud density and inhibit chlorobenzene polymerization and carbon deposition, significantly reducing the risk of chlorine poisoning and achieving long-term stable operation in complex flue gas environments containing HCl and chlorobenzene. Through the synergistic electronic effect of the three components, a "weak adsorption-rapid desorption" mode for chlorine species is achieved.

[0009] Preferably, the loading of the active component is 0.1~1.0 wt.%; The molar ratio of Pt, Pd, and Ru is (1~2):(1~3):(0.5~1). This ratio has been precisely optimized to maximize the utilization of noble metal atoms. By controlling the total loading below 1.0 wt.%, the catalyst cost is significantly reduced. Simultaneously, by adjusting the Pd / Ru ratio, an electron-rich environment is constructed on the Pt surface, weakening the chloride ion (Cl) content. - The binding energy between the catalyst and the Pt active center allows the catalyst to maintain excellent chlorine resistance even at extremely low loading.

[0010] Preferably, the specific surface area of ​​the anatase TiO2 support is 80~150 m². 2 / g, with a pore size of 5~20nm; the use of anatase TiO2 support is not only inexpensive, but its abundant Lewis acid sites on the surface help to anchor trace amounts of precious metal particles and prevent high-temperature sintering.

[0011] More preferably, the specific surface area of ​​the anatase TiO2 support is 100 m². 2 / g.

[0012] The second technical solution of the present invention: a method for preparing the above-mentioned CO oxidation catalyst resistant to chlorine poisoning, comprising the following steps: A complexing agent was added to a mixed solution of platinum salt, palladium salt and ruthenium salt to obtain a precursor solution of the active component (the system was in a naturally weakly acidic state (pH≈2~4)). The anatase TiO2 support was impregnated in the precursor solution of the active component, dried, and then calcined to obtain the CO oxidation catalyst resistant to chlorine poisoning.

[0013] Preferably, the complexing agent includes citric acid; The amount of citric acid used is 1 to 2 times the total mass of platinum salt, palladium salt and ruthenium salt, which can prevent the difference in precipitation rate between different metal ions, ensure the stability of the solution and the uniform distribution of Pt, Pd and Ru on the surface of the carrier.

[0014] The platinum salt includes chloroplatinic acid or platinum nitrate; The palladium salt includes palladium nitrate or palladium chloride; The ruthenium salts include ruthenium trichloride or ruthenium acetylacetonate.

[0015] Preferably, the impregnation temperature is room temperature and the time is 1-2 hours to ensure that the precursor solution fully enters the carrier pores.

[0016] Preferably, the drying temperature is 80~120℃ and the time is 6~12h.

[0017] More preferably, the drying temperature is 100°C and the time is 8 hours.

[0018] Preferably, the calcination atmosphere is air, the heating rate is 2~5℃ / min, the temperature is 450~550℃, and the time is 3~6h; the calcination process converts the metal salt into oxide and forms a Pt-Pd-Ru three-component mixed single atom on the surface of the support, while retaining the crystal structure of the anatase TiO2 support.

[0019] More preferably, the calcination heating rate is 2℃ / min, the temperature is 500℃, and the time is 4h.

[0020] More preferably, the solvent in the active component precursor solution is water or ethanol.

[0021] The method of the present invention does not require stepwise impregnation or reduction activation steps. The uniform dispersion of the three active components can be achieved by one-step co-impregnation and constant temperature calcination at 500°C. The preparation process is simple and suitable for industrial scale-up production.

[0022] This invention employs a one-step co-impregnation combined with isothermal calcination process, simplifying the cumbersome traditional multi-step impregnation procedure and improving production efficiency. By precisely controlling the pH value and complexation environment of the precursor solution, it ensures that the three metal ions can simultaneously decompose, migrate, and form uniformly dispersed Pt-Pd-Ru single atoms during drying and calcination, rather than simply undergoing physical mixing. The isothermal calcination at 500℃ ensures sufficient decomposition of the precursor while preventing excessively high temperatures from causing the anatase TiO2 support to transform into the rutile phase, thus maintaining the support's high specific surface area.

[0023] The calcination temperature of 500℃ is sufficient to convert the metal salt into oxide while retaining the surface hydroxyl groups of the anatase support. These hydroxyl groups help maintain the high dispersion of the metal particles during subsequent reduction and activation.

[0024] The third technical solution of the present invention: the application of the above-mentioned chlorine-resistant CO oxidation catalyst in the purification of chlorine- and CO-containing waste gas.

[0025] Preferably, the method of application includes: passing the chlorine- and CO-containing waste gas into the chlorine-resistant CO oxidation catalyst, and carrying out a CO catalytic oxidation reaction under heating conditions.

[0026] Preferably, the chlorine- and CO-containing waste gas includes waste incineration flue gas, chemical synthesis tail gas, or steel sintering flue gas.

[0027] Preferably, the chlorine in the chlorine- and CO-containing waste gas is one or more of chlorobenzene, HCl, and dioxins, with the concentration of HCl ≤200 ppm, the concentration of chlorobenzene ≤200 ppm, and the concentration of dioxins ≤200 ppm; the concentration of CO in the chlorine- and CO-containing waste gas is 1000~10000 mg / m³. 3 .

[0028] Preferably, the space velocity of the chlorine- and CO-containing waste gas is 10,000 to 60,000 h⁻¹. -1 The heating temperature is 150~500℃.

[0029] More preferably, the concentration of CO in the chlorine- and CO-containing waste gas is 10000 mg / m³. 3 .

[0030] More preferably, the concentration of HCl in the chlorine and CO-containing waste gas is 200 ppm, the concentration of chlorobenzene is 200 ppm, and the concentration of dioxin is 200 ppm.

[0031] More preferably, the space velocity of the chlorine- and CO-containing exhaust gas is 60,000 h⁻¹. -1 .

[0032] More preferably, the heating temperature is 200~500℃; this application parameter covers a variety of harsh operating conditions such as the steel industry, waste incineration, and chemical exhaust gas. The wide temperature window of 200~500℃ indicates that the catalyst can utilize the waste heat of industrial flue gas for the reaction, without the need for additional heating, resulting in significant energy savings. Even with only anatase TiO2 as the support and no other modifiers, a high conversion rate can be maintained with a total precious metal loading as low as 0.1 wt.%, demonstrating its extremely high industrial application value.

[0033] The CO oxidation catalyst of the present invention, which is resistant to chlorine poisoning, can achieve catalytic oxidation of CO in flue gas containing a high concentration of chlorobenzene / HCl / dioxin of 200 ppm, and no carbon deposits are generated on the catalyst surface after the reaction.

[0034] The present invention discloses the following technical effects: (1) The CO oxidation catalyst resistant to chlorine poisoning of the present invention has a space velocity of 60,000 h⁻¹ -1 CO concentration 10000 mg / m³ 3 Under harsh conditions containing 200 ppm HCl, 200 ppm chlorobenzene, or 200 ppm dioxin, complete CO conversion can be achieved at 165 °C, and the catalyst activity retention rate is >95% after 100 h of reaction.

[0035] (2) This invention combines the synergistic effect of Pt-Pd-Ru three components with the chlorine resistance of the anatase TiO2 support to reconstruct the chlorine adsorption energy on the catalyst surface, so that the chlorine species change from "strong chemical adsorption" to "weak adsorption-rapid desorption". Under an atmosphere containing 200ppm HCl, the activity decay is less than 5% in a 100h stability test, which solves the problem that traditional catalysts are deactivated when they come into contact with chlorine.

[0036] Secondly, this invention reduces the total loading of precious metals to below 1.0 wt.%, and through a simple process of one-step co-impregnation and constant-temperature calcination at 500°C, it achieves high dispersion of active components on the surface of anatase, significantly reducing manufacturing costs.

[0037] Furthermore, this invention solves the problem of carbon deposition in the catalyst by relying solely on the physicochemical stability of the anatase TiO2 support itself, combined with the C-Cl bond breaking ability of the Pd-Ru interface, thus achieving the dual effects of chlorine resistance and carbon deposition resistance.

[0038] (3) The catalyst of the present invention can achieve 100% CO conversion efficiency at temperatures below 200°C, and is particularly suitable for the deep treatment of low-temperature chlorine-containing flue gas.

[0039] (4) The preparation process of this invention is simple and the utilization rate of precious metals is high. It solves the problem of traditional catalysts being deactivated by chlorine and is particularly suitable for the deep purification of complex chlorine-containing flue gas such as waste incineration and chemical tail gas.

[0040] (5) In the catalyst of the present invention, the Pt component is responsible for the efficient activation of CO, the Pd component is specifically for capturing and converting chloride species, and the Ru component acts as a "buffer zone" to regulate the electronic structure and reduce the binding energy between chloride species and the active center. At the same time, by utilizing the moderate surface acidity and unique crystal structure of the anatase TiO2 support, the corrosion of chloride ions is blocked from both physical and chemical levels, thereby achieving efficient and stable removal of CO in complex chlorine-containing waste gas environments. Detailed Implementation

[0041] Various exemplary embodiments of the present invention will now be described in detail. This detailed description should not be considered as a limitation of the present invention, but rather as a more detailed description of certain aspects, features, and embodiments of the present invention.

[0042] 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, with respect to 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 in this invention. The upper and lower limits of these smaller ranges may be independently included or excluded from the range.

[0043] Unless otherwise stated, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art. While only preferred methods and materials have been described herein, any methods and materials similar or equivalent to those described herein may be used in the implementation or testing of this invention. All references to this specification are incorporated by way of citation to disclose and describe methods and / or materials associated with those references. In the event of any conflict with any incorporated reference, the content of this specification shall prevail.

[0044] 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 also be obvious to those skilled in the art. This specification and embodiments are merely exemplary.

[0045] The terms “include,” “including,” “have,” “contain,” etc., used in this article are all open-ended terms, meaning that they include but are not limited to.

[0046] It should be noted that any aspects not described in detail in this invention are conventional practices in the field and are not the focus of this invention.

[0047] Example 1 A method for preparing a CO oxidation catalyst resistant to chlorine poisoning: (1) Dissolve 0.13g chloroplatinic acid (H2PtCl6·6H2O), 0.066g palladium nitrate (Pd(NO3)2·2H2O) and 0.065g ruthenium trichloride (RuCl3·3H2O) in 100mL of deionized water, add 0.5g citric acid, stir for 30min to obtain the active component precursor solution.

[0048] (2) 100g of anatase TiO2 support (specific surface area of ​​100m²) 2 The catalyst (Pt, Pd and Ru) was immersed in an equal volume of active component precursor solution, stirred and impregnated at room temperature for 1 h, dried at 100 °C for 8 h, and calcined at 500 °C for 4 h in air atmosphere at a heating rate of 2 °C / min to obtain a CO oxidation catalyst resistant to chlorine poisoning (total loading of Pt, Pd and Ru is 0.1 wt.%, Pt:Pd:Ru (molar ratio) = 1:1:1).

[0049] Example 2 A method for preparing a CO oxidation catalyst resistant to chlorine poisoning: (1) Dissolve 0.44 g chloroplatinic acid (H2PtCl6·6H2O), 0.23 g palladium nitrate (Pd(NO3)2·2H2O) and 0.11 g ruthenium trichloride (RuCl3·3H2O) in 100 mL of deionized water, add 1.56 g citric acid, stir for 30 min to obtain the active component precursor solution.

[0050] (2) 100g of anatase TiO2 support (specific surface area of ​​100m²) 2 The catalyst (Pt, Pd and Ru) was immersed in an equal volume of active component precursor solution, stirred and impregnated at room temperature for 1 h, dried at 100 °C for 8 h, and calcined at 500 °C for 4 h in air atmosphere at a heating rate of 2 °C / min to obtain a CO oxidation catalyst resistant to chlorine poisoning (total loading of Pt, Pd and Ru is 0.3 wt.%, Pt:Pd:Ru (molar ratio) = 1:1:0.5).

[0051] Example 3 A method for preparing a CO oxidation catalyst resistant to chlorine poisoning: (1) Dissolve 0.675g chloroplatinic acid (H2PtCl6·6H2O), 1.040g palladium nitrate (Pd(NO3)2·2H2O) and 0.341g ruthenium trichloride (RuCl3·3H2O) in 100mL of deionized water, add 3.0g citric acid, stir for 30min to obtain the active component precursor solution.

[0052] (2) 100g of anatase TiO2 support (specific surface area of ​​100m²) 2 The catalyst (Pt, Pd and Ru) was immersed in an equal volume of active component precursor solution, stirred and impregnated at room temperature for 1 h, dried at 100 °C for 8 h, and calcined at 500 °C for 4 h in air atmosphere at a heating rate of 2 °C / min to obtain a CO oxidation catalyst resistant to chlorine poisoning (total loading of Pt, Pd and Ru is 0.8 wt.%, Pt:Pd:Ru (molar ratio) = 1:3:1).

[0053] Example 4 A method for preparing a CO oxidation catalyst resistant to chlorine poisoning: (1) Dissolve 1.28g chloroplatinic acid (H2PtCl6·6H2O), 0.85g palladium nitrate (Pd(NO3)2·2H2O) and 0.26g ruthenium trichloride (RuCl3·3H2O) in 100mL of deionized water, add 3.6g citric acid, stir for 30 min to obtain the active component precursor solution.

[0054] (2) 100g of anatase TiO2 support (specific surface area of ​​100m²) 2The catalyst (Pt, Pd and Ru) was immersed in an equal volume of active component precursor solution, stirred and impregnated at room temperature for 1 h, dried at 100 °C for 8 h, and calcined at 500 °C for 4 h in air atmosphere at a heating rate of 2 °C / min to obtain a CO oxidation catalyst resistant to chlorine poisoning (total loading of Pt, Pd and Ru is 1.0 wt.%, Pt:Pd:Ru (molar ratio) = 2:3:1).

[0055] Example 5 A method for preparing a CO oxidation catalyst resistant to chlorine poisoning: (1) Dissolve 0.91g chloroplatinic acid (H2PtCl6·6H2O), 0.43g palladium nitrate (Pd(NO3)2·2H2O) and 0.21g ruthenium trichloride (RuCl3·3H2O) in 100mL of deionized water, add 2.3g citric acid, stir for 30 min to obtain the active component precursor solution.

[0056] (2) 100g of anatase TiO2 support (specific surface area of ​​100m²) 2 The catalyst (Pt, Pd and Ru) was immersed in an equal volume of active component precursor solution, stirred and impregnated at room temperature for 1 h, dried at 100 °C for 8 h, and calcined at 500 °C for 4 h in air atmosphere at a heating rate of 2 °C / min to obtain a CO oxidation catalyst resistant to chlorine poisoning (total loading of Pt, Pd and Ru is 0.6 wt.%, Pt:Pd:Ru (molar ratio) = 2:1:0.5).

[0057] Comparative Example 1 A method for preparing a Pt / TiO2 catalyst: (1) Dissolve 0.266g of chloroplatinic acid (H2PtCl6·6H2O) in 100mL of deionized water, add 0.4g of citric acid, stir for 30 min to obtain the active component precursor solution.

[0058] (2) 100g of anatase TiO2 support (specific surface area of ​​100m²) 2 The Pt / TiO2 catalyst (with a pore size of 5~20nm) was immersed in an equal volume of active component precursor solution, stirred and impregnated at room temperature for 1h, dried at 100℃ for 8h, and calcined at 500℃ for 4h in air atmosphere at a heating rate of 2℃ / min to obtain the Pt / TiO2 catalyst (Pt loading is 0.1wt.%).

[0059] Comparative Example 2 A method for preparing a Pd / TiO2 catalyst: (1) Dissolve 0.216g palladium nitrate (Pd(NO3)2·2H2O) in 100mL deionized water, add 0.32g citric acid, stir for 30min to obtain the active component precursor solution.

[0060] (2) 100g of anatase TiO2 support (specific surface area of ​​100m²) 2 The Pd / TiO2 catalyst (with a pore size of 5~20nm) was immersed in an equal volume of active component precursor solution, stirred and impregnated at room temperature for 1h, dried at 100℃ for 8h, and calcined at 500℃ for 4h in air atmosphere at a heating rate of 2℃ / min to obtain the Pd / TiO2 catalyst (Pd loading is 0.1wt.%).

[0061] Comparative Example 3 A method for preparing a Pt-Pd / TiO2 catalyst: (1) Dissolve 0.171g chloroplatinic acid (H2PtCl6·6H2O) and 0.076g palladium nitrate (Pd(NO3)2·2H2O) in 100mL of deionized water, add 0.37g citric acid, stir for 30 min to obtain the active component precursor solution.

[0062] (2) 100g of anatase TiO2 support (specific surface area of ​​100m²) 2 The Pt-Pd / TiO2 catalyst (with a pore size of 5~20nm) was immersed in an equal volume of active component precursor solution, stirred and impregnated at room temperature for 1h, dried at 100℃ for 8h, and calcined at 500℃ for 4h in air atmosphere at a heating rate of 2℃ / min to obtain the catalyst (the total loading of Pt and Pd is 0.1wt.%).

[0063] Comparative Example 4 A method for preparing a Pt-Ru / TiO2 catalyst: (1) Dissolve 0.133g chloroplatinic acid (H2PtCl6·6H2O) and 0.067g ruthenium trichloride (RuCl3·3H2O) in 100mL of deionized water, add 0.30g citric acid, stir for 30 min to obtain the active component precursor solution.

[0064] (2) 100g of anatase TiO2 support (specific surface area of ​​100m²) 2 The Pt-Ru / TiO2 catalyst (with a pore size of 5~20nm) was immersed in an equal volume of active component precursor solution, stirred and impregnated at room temperature for 1h, dried at 100℃ for 8h, and calcined at 500℃ for 4h in air atmosphere at a heating rate of 2℃ / min to obtain the catalyst (the total loading of Pt and Ru is 0.1wt.%).

[0065] Comparative Example 5 A method for preparing a Pd-Ru / TiO2 catalyst: (1) Dissolve 0.138g palladium nitrate (Pd(NO3)2·2H2O) and 0.129g ruthenium trichloride (RuCl3·3H2O) in 100mL of deionized water, add 0.27g citric acid, stir for 30min to obtain the active component precursor solution.

[0066] (2) 100g of anatase TiO2 support (specific surface area of ​​100m²) 2 The catalyst (Pd-Ru / TiO2 catalyst with a pore size of 5~20nm) was immersed in an equal volume of active component precursor solution, stirred and impregnated at room temperature for 1h, dried at 100℃ for 8h, and calcined at 500℃ for 4h in air atmosphere at a heating rate of 2℃ / min to obtain Pd-Ru / TiO2 catalyst (total loading of Pd and Ru is 0.1wt.%).

[0067] Comparative Example 6 A method for preparing a Pt-Pd-Ni / TiO2 catalyst (1) Dissolve 0.132g chloroplatinic acid (H2PtCl6·6H2O), 0.069g palladium nitrate (Pd(NO3)2·2H2O), and 0.124g nickel nitrate hexahydrate in 100mL of deionized water, add 0.45g citric acid, stir for 30min to obtain the active component precursor solution.

[0068] (2) 100g of anatase TiO2 support (specific surface area of ​​100m² / g, pore size of 5~20nm) was immersed in an equal volume of active component precursor solution, stirred and impregnated at room temperature for 1h, dried at 100℃ for 8h, and calcined at 500℃ for 4h at a heating rate of 2℃ / min in air atmosphere to obtain Pt-Pd-Ni / TiO2 catalyst (total loading of Pt, Pd, and Ni is 0.1wt.%).

[0069] Comparative Example 7 A method for preparing a Pt-Pd-Ru / TiO2 catalyst: (1) Dissolve 0.13g chloroplatinic acid (H2PtCl6·6H2O), 0.066g palladium nitrate (Pd(NO3)2·2H2O), and 0.065g ruthenium trichloride (RuCl3·3H2O) in 100mL of deionized water, add 0.25g oxalic acid, stir for 30min to obtain the active component precursor solution.

[0070] (2) 100g of anatase TiO2 support (specific surface area of ​​100m²) 2The Pt-Pd-Ru / TiO2 catalyst (with a pore size of 5~20nm) was immersed in an equal volume of active component precursor solution, stirred and impregnated at room temperature for 1h, dried at 100℃ for 8h, and calcined at 500℃ for 4h in air atmosphere at a heating rate of 2℃ / min to obtain the catalyst (the total loading of Pt, Pd, and Ru is strictly 0.1wt.%).

[0071] Comparative Example 8 A method for preparing a Pt-Pd-Ru / TiO2 catalyst: (1) Dissolve 0.13g chloroplatinic acid (H2PtCl6·6H2O), 0.066g palladium nitrate (Pd(NO3)2·2H2O), and 0.065g ruthenium trichloride (RuCl3·3H2O) in 100mL of deionized water, add 0.45g citric acid, and stir for 30 min to obtain the active component precursor solution.

[0072] (2) 100g of anatase TiO2 support (specific surface area of ​​100m²) 2 The Pt-Pd-Ru / TiO2 catalyst (with a pore size of 5-20 nm) was immersed in an equal volume of active component precursor solution, stirred and impregnated at room temperature for 1 h, and dried at 100 °C for 8 h. The catalyst was then calcined at 700 °C for 4 h in air at a heating rate of 2 °C / min to obtain the catalyst (total loading of Pt, Pd, and Ru was 0.1 wt.%).

[0073] Excessive calcination temperature leads to performance degradation.

[0074] Example 1 (1) The catalysts prepared in the examples and comparative examples were tested for their resistance to HCl poisoning. The test conditions included: fixed-bed reactor, catalyst loading of 200 mg, and space velocity of 60,000 h⁻¹. -1 Flue gas composition: [CO] = 10000 mg / m³ 3 [O2] = 10 vol%, [HCl] = 200 ppm, N2 is the balance gas; the reactor temperature is set to 150~500℃, and the test results are shown in Table 1.

[0075] Table 1 Evaluation of resistance to HCl poisoning (2) The catalysts prepared in the examples and comparative examples were tested for their resistance to chlorobenzene poisoning. The test conditions included: fixed-bed reactor, catalyst loading of 200 mg, and space velocity of 60,000 h⁻¹. -1 Flue gas composition: [CO] = 10000 mg / m³ 3[O2] = 10 vol%, [chlorobenzene] = 200 ppm, N2 is the balance gas; the reactor temperature is set to 150~500℃, and the test results are shown in Table 2.

[0076] Table 2 Evaluation of resistance to chlorobenzene poisoning As can be seen from Tables 1 and 2, the chlorine-resistant CO oxidation catalyst prepared in the embodiments of the present invention still maintains excellent CO oxidation performance under a chlorine-containing atmosphere. At a low loading of 0.1 wt.% (Example 1), the catalyst, in flue gas containing 200 ppm HCl or 200 ppm chlorobenzene, T 100 All of them were able to maintain a temperature of 310℃, demonstrating excellent minimum performance.

[0077] As can be seen from the comparison of Examples 1-5, in the HCl poisoning resistance test, as the total loading of the active component increases from 0.1 wt.% to 1.0 wt.%, the catalyst's T... 100 The temperature decreased significantly from 310℃ to 155℃. This indicates that increasing the number of active sites is an effective way to improve the reaction rate and reduce the complete conversion temperature.

[0078] As can be seen from the comparison between Example 1 and Comparative Examples 1-5, in the HCl poisoning resistance test, single metal or bimetallic catalysts are almost ineffective in a chlorine-containing atmosphere (T 100 All are above 440℃. This proves the necessity of the synergistic effect of the Pt-Pd-Ru tricomponents: Pt is the main active center for CO oxidation, Pd is responsible for the specific adsorption and dissociation of Cl species, and Ru regulates the surface electron cloud density and inhibits the polymerization and carbon deposition of chlorobenzene. All three are indispensable.

[0079] As can be seen from the comparison between Example 1 and Comparative Examples 1-5, in the chlorobenzene poisoning resistance test, the absence of any one metal will lead to T 100 The temperature rises sharply to over 370°C, and deep dehydrogenation polymerization easily occurs on the catalyst surface, forming dense coke-like material. This further verifies that the three-component alloy structure can effectively break C-Cl bonds, prevent pore blockage, and maintain the long-term stable operation of the catalyst.

[0080] The CO oxidation catalyst prepared in this invention, resistant to chlorine poisoning, solves the problems of easy chlorination deactivation and carbon buildup in chlorine-containing waste gas even with a total active component loading as low as 0.1 wt.%. This invention utilizes the chlorine species capture and cracking function of the Pd-Ru interface, combined with the acid corrosion resistance of anatase TiO2, to achieve high space velocities (60,000 h⁻¹) even with 200 ppm HCl or 200 ppm chlorobenzene. -1 The efficient and stable removal of CO from flue gas fully meets the application needs of complex industrial scenarios such as waste incineration and chemical exhaust gas.

[0081] Furthermore, the CO oxidation catalyst for resisting chlorine poisoning of the present invention can convert chlorobenzene into HCl, CO2, and H2O.

[0082] Example 2 Activity retention rate Infrared mass spectrometry analysis revealed that the catalyst prepared in Example 4 retained >95% of its activity after 100 hours of reaction.

[0083] Example 3 The catalyst prepared in Example 4 was tested for its resistance to HCl and chlorobenzene poisoning. The test conditions included: a fixed-bed reactor, a catalyst loading of 200 mg, and a space velocity of 60,000 h⁻¹. -1 Flue gas composition: [CO] = 10000 mg / m³ 3 [O2] = 10 vol%, [HCl] = 200 ppm, [chlorobenzene] = 200 ppm, N2 is the balance gas; the reactor temperature is set to 150~500℃.

[0084] Test results showed that when multiple forms of chlorine species (HCl and chlorobenzene) are present simultaneously, the catalyst prepared in Example 4 will completely convert CO at 180°C and operate stably for a long time.

[0085] The embodiments described above are merely preferred embodiments of the present invention and are not intended to limit the scope of the present invention. Various modifications and improvements made by those skilled in the art to the technical solutions of the present invention without departing from the spirit of the present invention should fall within the protection scope defined by the claims of the present invention.

Claims

1. A CO oxidation catalyst resistant to chlorine poisoning, characterized in that, Includes anatase TiO2 support and active components loaded on the support; The active components include Pt, Pd, and Ru.

2. The CO oxidation catalyst resistant to chlorine poisoning according to claim 1, characterized in that, The loading of the active component is 0.1~1.0 wt.%; And / or, the molar ratio of Pt, Pd and Ru is (1~2):(1~3):(0.5~1).

3. The CO oxidation catalyst resistant to chlorine poisoning according to claim 1, characterized in that, The specific surface area of ​​the anatase TiO2 support is 80~150m². 2 / g, with a pore size of 5~20nm.

4. A method for preparing a CO oxidation catalyst resistant to chlorine poisoning as described in any one of claims 1 to 3, characterized in that, Includes the following steps: A complexing agent is added to a mixed solution of platinum salt, palladium salt and ruthenium salt to obtain a precursor solution of the active component; The anatase TiO2 support was impregnated in the precursor solution of the active component, dried, and then calcined to obtain the CO oxidation catalyst resistant to chlorine poisoning.

5. The preparation method according to claim 4, characterized in that, The complexing agent includes citric acid; The amount of citric acid used is 1 to 2 times the total mass of the platinum salt, palladium salt, and ruthenium salt; And / or, the platinum salt includes chloroplatinic acid or platinum nitrate; And / or, the palladium salt includes palladium nitrate or palladium chloride; And / or, the ruthenium salt includes ruthenium trichloride or ruthenium acetylacetonate.

6. The preparation method according to claim 4, characterized in that, The soaking time is 1 to 2 hours.

7. The preparation method according to claim 4, characterized in that, The drying temperature is 80~120℃, and the time is 6~12h.

8. The preparation method according to claim 4, characterized in that, The calcination atmosphere is air, the heating rate is 2~5℃ / min, the temperature is 450~550℃, and the time is 3~6h.

9. The application of the chlorine-resistant CO oxidation catalyst according to any one of claims 1 to 3 in the purification of chlorine- and CO-containing waste gas.

10. The application according to claim 9, characterized in that, The method of application includes: passing the chlorine- and CO-containing waste gas into the chlorine-resistant CO oxidation catalyst, and carrying out a CO catalytic oxidation reaction under heating conditions.

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