A composite catalyst for catalyzing organic pollutants at low temperature, and a preparation method and application thereof

Abstract

The application discloses a composite catalyst for low-temperature catalysis of organic pollutants and a preparation method and application thereof. The catalyst is prepared by taking TiO2 as a carrier, a copper-manganese-cerium composite oxide and a loaded noble metal platinum as active components of the catalyst; the weight percentage of the copper-manganese-cerium composite oxide is 10%, the weight percentage of the TiO2 carrier is 80%-90%, and the weight percentage of the noble metal platinum is 0.1%-1%; in the copper-manganese-cerium composite oxide, the molar ratio of copper, manganese and cerium is 1:(3-4):(0.5-1). The material is synthesized by adjusting the proportion of tetrabutyl titanate, glacial acetic acid and ethanol through a sol-gel method to obtain TiO2 with an ordered mesoporous structure, and the loaded noble metal platinum and copper-manganese-cerium metal oxide enable the material to have excellent low-temperature catalytic performance, a significantly improved organic pollutant removal efficiency, a greatly reduced production cost, and good adaptability to large-scale production and industrial application prospects.

Description

Technical Field

[0001] This invention belongs to the field of gas purification and treatment, specifically relating to a composite catalyst for low-temperature catalysis of organic pollutants, its preparation method, and its application. Background Technology

[0002] Organic pollutants, as key precursors to secondary organic aerosols and near-surface ozone formation, not only exacerbate air pollution through photochemical reactions but also pose a direct threat to human health due to their carcinogenic, teratogenic, and mutagenic effects. These substances are widely present in exhaust emissions from chemical, petrochemical, and related industries, and their emission intensity has increased significantly with the acceleration of urbanization and industrialization.

[0003] In recent years, many scholars have applied various nanomaterials as catalysts for the catalytic degradation of organic pollutants and investigated their physicochemical properties and catalytic performance. Among them, noble metal-supported composite oxide catalysts, with their advantages of high catalytic activity, excellent stability, and resistance to poisoning, are widely used in the field of industrial catalytic combustion. In the catalytic combustion of organic pollutants, the catalyst promotes the flameless combustion reaction of organic pollutants at an ignition temperature far lower than the conventional combustion temperature. In this process, the originally toxic organic pollutants are decomposed into non-toxic carbon dioxide and water, thereby achieving effective treatment of harmful substances in industrial waste gas and meeting environmental protection standards.

[0004] However, highly toxic organic pollutants generated from incinerators and vehicle exhaust, such as chlorobenzene, dioxins, aromatic hydrocarbons, and alkanes, have high boiling points and high catalytic ignition temperatures. Existing catalysts, designed for these high boiling points, suffer from high energy consumption and are prone to generating byproducts that cause secondary pollution. Therefore, there is an urgent need to develop a low-temperature catalyst and its preparation method to enable the combustion and transformation of these highly toxic organic pollutants at relatively low temperatures, thereby achieving energy conservation, emission reduction, and cost reduction. Summary of the Invention

[0005] To address the technical problems existing in the prior art, the primary objective of this invention is to provide a composite catalyst for the low-temperature catalysis of organic pollutants. This catalyst is synthesized in one step via a sol-gel method by mixing titanate with copper, manganese, and cerium nitrate solutions, thereby synthesizing a Cu-Mn-Ce-Ti oxide support. TiO2 provides a rigid framework (mainly anatase phase, with stable crystal structure), and CeO2... x Introducing a large number of oxygen vacancies (Ce 3+ / Ce 4+ Redox pairs), Cu / Mn ions (Cu 2+ / Cu + Mn 4+ / Mn 3+Pt nanoparticles are dispersed in the crystal lattice to form defect sites. The impregnation reduction method is used to uniformly disperse Pt nanoparticles in the mesoporous channels of Cu-Mn-Ce-Ti oxide support. At low temperature, organic pollutants diffuse rapidly to the Pt surface through the mesopores, while oxygen in the support lattice migrates to the periphery of Pt through the channel interface, shortening the "adsorption-activation-reaction" path.

[0006] Another object of the present invention is to provide a method for preparing the above-mentioned catalyst.

[0007] Another object of the present invention is to provide the application of the above-mentioned catalyst in the low-temperature catalytic oxidation of organic pollutants.

[0008] To achieve this objective, the present invention adopts the following technical solution:

[0009] A composite catalyst for low-temperature catalysis of organic pollutants, characterized in that the catalyst uses TiO2 as a support and copper-manganese-cerium composite oxide and noble metal platinum as active components;

[0010] The TiO2 support comprises 80% to 90% by weight; the copper-manganese-cerium composite oxide comprises 10% to 20% by weight; and the noble metal platinum comprises 0.1% to 1% by weight.

[0011] In the copper-manganese-cerium composite oxide, the molar ratio of copper, manganese, and cerium is 1:(3-4):(0.5-1).

[0012] Preferably, the TiO2 support is synthesized via a sol-gel method, has a mesoporous structure, and a specific surface area of ​​100-110 m² / g. 2 / g, with an average pore size of 9–10 nm.

[0013] Preferably, it includes the following steps:

[0014] (1) Mix titanate, glacial acetic acid and anhydrous ethanol to obtain solution A; dissolve copper salt, manganese salt and cerium salt in ultrapure water and stir to obtain solution B; add solution B dropwise to solution A, stir and heat in a water bath to obtain a mixed gel;

[0015] (2) The mixed gel obtained in step (1) is dried, calcined, ground and sieved to obtain a copper manganese cerium titanium catalyst.

[0016] (3) Add the copper-manganese-cerium-titanium catalyst obtained in step (2) to ultrapure water, then add chloroplatinic acid solution dropwise and stir; add sodium borohydride and sodium hydroxide mixed solution to the mixture and stir continuously;

[0017] (4) The solution obtained in step (3) is centrifuged and washed multiple times with ultrapure water and then vacuum dried to obtain the composite catalyst.

[0018] Preferably, in step (1),

[0019] The molar ratio of titanate, glacial acetic acid, and anhydrous ethanol is (1-2):(1-4):(4-8);

[0020] The molar ratio of the metal elements in the copper salt, manganese salt, and cerium salt is 1:4:1;

[0021] The water bath heating temperature is 60–80°C;

[0022] The titanate is tetrabutyl titanate; the copper salt is CuSO4 or Cu(NO3)2·3H2O; the manganese salt is MnSO4·4H2O, Mn(NO3)2 or MnCO3; and the cerium salt is Ce(NO3)3·6H2O.

[0023] Preferably, in step (2),

[0024] The drying conditions are 90–110°C, and the drying time is 20–30 h;

[0025] The calcination conditions are as follows: heating at 2-5℃ / min to 300-600℃ and calcining for 4-6 hours;

[0026] The grinding and sieving process uses a mesh size of 60.

[0027] Preferably, in step (3), the volume of the sodium borohydride and sodium hydroxide mixed solution is 1 to 5 mL.

[0028] Preferably, in step (4), the washing refers to washing until no Cl is present. - Vacuum drying conditions are 60–80℃ for 24–30 hours.

[0029] The present invention relates to the application of a low-temperature catalytic composite catalyst for organic pollutants in the catalytic oxidation of organic pollutants.

[0030] Preferably, the organic pollutant is benzene or n-hexane.

[0031] Preferably, the treatment conditions for the catalytic oxidation of organic pollutants are as follows: the concentration of organic pollutants in the mixed gas is 400 ppm, the reaction temperature is 30-300℃, the simulated temperature rise rate is 2℃ / min, and the ignition temperature is 100-125℃.

[0032] Compared with the prior art, the present invention has at least the following beneficial effects:

[0033] (1) The low-temperature organic pollutant catalyst and its preparation method: During the catalyst preparation process, an ordered mesoporous TiO2 support with a specific surface area of ​​100-110 m² was synthesized by the sol-gel method. 2 / g, with an average pore size of 10nm, the high specific surface area is conducive to exposing more active sites. The appropriate pore size distribution can provide good diffusion channels, enabling reactants to diffuse rapidly to the vicinity of active sites, while products can also desorb from active sites and diffuse out in a timely manner, thereby improving the efficiency of catalytic reaction.

[0034] (2) The low-temperature organic pollutant catalyst and its preparation method: During the catalyst preparation process, a highly dispersed and low-loaded copper-manganese-cerium-titanium composite oxide was formed by a one-step synthesis method. EDS characterization showed that copper, manganese and cerium elements were uniformly distributed on the TiO2 surface. The low loading can reduce the content of copper, manganese and cerium elements in the composite oxide, reduce the reduction of catalyst active sites and pore structure destruction caused by element agglomeration and sintering, thereby enhancing the performance of the catalyst.

[0035] (3) The low-temperature organic pollutant catalyst and its preparation method: During the catalyst preparation process, noble metal solutions such as chloroplatinic acid or tetraammineplatinum acetate are loaded by impregnation reduction method and uniformly dispersed on the surface of copper manganese cerium titanium catalyst by mechanical stirring. Some Pt ​​is dispersed in the form of single atoms on Cu-Mn-O active sites, and the other part forms small nanoparticles. XPS characterization shows that the binding energy of Pt atoms has shifted by 0.4 eV, which may be because the defect sites at the interface between Pt nanoparticles and the support become the main reaction centers, and electrons are transferred from the support to Pt to form electron-rich active centers.

[0036] (4) The present invention has the advantages of simple synthesis steps, low energy consumption (no need for secondary calcination) and low reaction temperature. Attached Figure Description

[0037] Figure 1 The curves show the comparison of the catalytic efficiency of the composite oxide catalyst prepared in Example 1 of this invention for different gases.

[0038] Figure 2 This is a comparison chart of the catalytic efficiency of the composite oxide catalyst prepared in Example 1 of the present invention and the cerium-titanium catalyst supported by the noble metal platinum in Comparative Example 1 for catalyzing benzene.

[0039] Figure 3 The images show the XRD patterns of the titanium composite oxide catalysts prepared in Examples 1-3 of this invention.

[0040] Figures 4(a)(b)(c) are XPS images of the composite oxide catalyst prepared in Example 1 of the present invention.

[0041] Figure 5 This is a TEM image of the composite oxide catalyst prepared in Example 1 of the present invention.

[0042] Figures 6(a) and (b) are BET diagrams of the composite oxide catalyst prepared in Example 1 of the present invention.

[0043] Figure 7 This is a SEM image of the composite oxide catalyst prepared in Example 1 of the present invention.

[0044] Figure 8 This is an EDS diagram of the composite oxide catalyst prepared in Example 1 of the present invention. Detailed Implementation

[0045] The technical solutions in the embodiments of the present invention will now be clearly and completely described with reference to the accompanying drawings. The described embodiments are merely some, not all, of the embodiments of the present invention. Other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are all within the scope of protection of the present invention. Unless otherwise specified, the experimental methods described in the following embodiments are conventional methods; the reagents and materials, unless otherwise specified, can be obtained from publicly available commercial channels.

[0046] This specification uses spatially relative terms such as “below,” “under,” “down,” “above,” “above,” and “upper” to explain the positioning of one element relative to a second element. These terms are intended to cover different orientations of the device, except for those different from those shown in the figures.

[0047] Furthermore, the use of terms such as "first" and "second" to describe various elements, layers, regions, and sections is not intended to be restrictive. The use of terms such as "having," "containing," "including," and "comprises" are open-ended terms, indicating the presence of the stated elements or features, but not excluding additional elements or features, unless the context explicitly states otherwise.

[0048] Example 1

[0049] In this embodiment, a catalyst was prepared with approximately 89% TiO2 support, approximately 10% copper-manganese-cerium composite oxide, and approximately 1% platinum (a noble metal). The steps are as follows:

[0050] 8.2 g of tetrabutyl titanate, 5.76 g of glacial acetic acid, and 8.84 g of anhydrous ethanol were mixed in a molar ratio of 1:4:8 to obtain solution A. 0.056 g of Cu(NO3)2·3H2O, 0.23 g of Mn(NO3)2·4H2O, and 0.089 g of Ce(NO3)3·6H2O were dissolved in 20 ml of ultrapure water and stirred at room temperature and pressure for 1 hour to obtain solution B, in which the molar ratio of copper, manganese, and cerium was 1:4:1. Solution B was added dropwise to solution A, and the mixture was stirred at a constant speed in a water bath for 2 hours. The mixture was then heated to 80 °C to obtain a mixed gel. The gel was dried in a vacuum drying oven at 90 °C for 24 hours to obtain a black blocky solid, which was then calcined in a muffle furnace at a heating rate of 2 °C / min to 500 °C for 4 hours. The calcined solid was ground and sieved to 60 mesh to obtain the copper-manganese-cerium-titanium catalyst. 0.15 g of the obtained copper-manganese-cerium-titanium catalyst powder and 252 μL of a 0.03 mol / L H₂PtCl₆·6H₂O solution (with a platinum loading of 1%) were dispersed in 30 mL of ultrapure water and stirred at room temperature for 2 hours to obtain solution C. 1 mL of a mixed solution of sodium borohydride and sodium hydroxide was added to solution C, and stirring was continued for 4 hours. The resulting solution was centrifuged and washed multiple times with ultrapure water until no Cl₂ was found. - The copper-manganese-cerium composite oxide catalyst supported on the noble metal platinum was obtained by vacuum drying at 60℃ for 24 hours.

[0051] Figure 1 The efficiency curves for the composite oxide catalyst prepared in Example 1 catalyzing benzene and n-hexane are shown. The catalytic conditions were: organic pollutant concentration of 400 ppm, reaction temperature of 30–300 °C, and simulated temperature ramp rate of 2 °C / min. Figure 1 It can be seen that the ignition temperature of the catalytic oxidation of organic pollutants is between 100-125℃. At 200℃, the catalytic efficiency for n-hexane reaches over 90%; at 250℃, the catalytic efficiency for benzene is close to 100%. Considering the complex structure and extremely high toxicity of dioxins, benzene was selected as the model for this experiment—both contain aromatic ring conjugated structures, and the catalytic oxidation reaction pathway of benzene can effectively simulate the key aromatic ring opening and carbon chain breaking steps in the degradation of dioxins. Figure 6 shows the BET diagram of the composite oxide catalyst in Example 1, which shows that the specific surface area of ​​the catalyst is 100-110 m². 2 / g, with an average pore size of 9–10 nm.

[0052] Example 2

[0053] In this embodiment, a catalyst was prepared with approximately 89.5% TiO2 support, approximately 10% copper-manganese-cerium composite oxide, and approximately 0.5% platinum (a noble metal). The steps are as follows:

[0054] 8.2 g of tetrabutyl titanate, 5.76 g of glacial acetic acid, and 8.84 g of anhydrous ethanol were mixed in a molar ratio of 1:4:8 to obtain solution A. 0.056 g of Cu(NO3)2·3H2O, 0.23 g of Mn(NO3)2·4H2O, and 5.76 g of Ce(NO3)3·6H2O were dissolved in 20 mL of ultrapure water and stirred at room temperature and pressure for 1 hour to obtain solution B, in which the molar ratio of copper, manganese, and cerium was 1:4:1. Solution B was added dropwise to solution A, and the mixture was stirred at a constant speed in a water bath for 2 hours. The mixture was then heated to 80 °C to obtain a mixed gel. The gel was dried in a vacuum drying oven at 90 °C for 24 hours to obtain a black blocky solid, which was then calcined in a muffle furnace at a heating rate of 2 °C / min to 500 °C for 4 hours. The calcined solid was ground and sieved to 60 mesh to obtain the copper-manganese-cerium-titanium catalyst. 0.15 g of the obtained copper-manganese-cerium-titanium catalyst powder and 126 μL of a 0.03 mol / L H₂PtCl₆·6H₂O solution (with a platinum loading of 0.5%) were dispersed in 30 mL of ultrapure water and stirred at room temperature for 2 hours to obtain solution C. 1 mL of a mixed solution of sodium borohydride and sodium hydroxide was added to solution C, and stirring was continued for 4 hours. The resulting solution was centrifuged and washed multiple times with ultrapure water until no Cl₂ was found. - The copper-manganese-cerium-titanium composite oxide catalyst supported on noble metal platinum was obtained by vacuum drying at 60℃ for 24 hours.

[0055] Example 3

[0056] In this embodiment, a catalyst was prepared with approximately 89.9% TiO2 support, approximately 10% copper-manganese-cerium composite oxide, and approximately 0.1% platinum (a noble metal). The steps are as follows:

[0057] 8.2 g of tetrabutyl titanate, 5.76 g of glacial acetic acid, and 8.84 g of anhydrous ethanol were mixed in a molar ratio of 1:4:8 to obtain solution A. 0.056 g of Cu(NO3)2·3H2O, 0.23 g of Mn(NO3)2·4H2O, and 0.089 g of Ce(NO3)3·6H2O were dissolved in 20 ml of ultrapure water and stirred at room temperature and pressure for 1 hour to obtain solution B, in which the molar ratio of copper, manganese, and cerium was 1:4:1. Solution B was added dropwise to solution A, and the mixture was stirred at a constant speed in a water bath for 2 hours. The mixture was then heated to 80 °C to obtain a mixed gel. The gel was dried in a vacuum drying oven at 90 °C for 24 hours to obtain a black blocky solid, which was then calcined in a muffle furnace at a heating rate of 2 °C / min to 500 °C for 4 hours. The calcined solid was ground and sieved to 60 mesh to obtain the copper-manganese-cerium-titanium catalyst. 0.15 g of the obtained copper-manganese-cerium-titanium catalyst powder and 26 μL of a 0.03 mol / L H₂PtCl₆·6H₂O solution (with a platinum loading of 0.1%) were dispersed in 30 mL of ultrapure water and stirred at room temperature for 2 hours to obtain solution C. 1 mL of a mixed solution of sodium borohydride and sodium hydroxide was added to solution C, and stirring was continued for 4 hours. The resulting solution was centrifuged and washed multiple times with ultrapure water until no Cl₂ was found. - The copper-manganese-cerium-titanium composite oxide catalyst supported on noble metal platinum was obtained by vacuum drying at 60℃ for 24 hours.

[0058] Example 4

[0059] In this embodiment, a catalyst was prepared with approximately 89% TiO2 support, approximately 10% copper-manganese-cerium composite oxide, and approximately 1% platinum (a noble metal). The steps are as follows:

[0060] 8.2 g of tetrabutyl titanate, 1.44 g of glacial acetic acid, and 8.84 g of anhydrous ethanol were mixed in a molar ratio of 1:1:8 to obtain solution A. 0.056 g of Cu(NO3)2·3H2O, 0.23 g of Mn(NO3)2·4H2O, and 0.089 g of Ce(NO3)3·6H2O were dissolved in 20 ml of ultrapure water and stirred at room temperature and pressure for 1 hour to obtain solution B, in which the molar ratio of copper, manganese, and cerium was 1:4:1. Solution B was added dropwise to solution A, and the mixture was stirred at a constant speed in a water bath for 2 hours. The mixture was then heated to 80 °C to obtain a mixed gel. The gel was dried in a vacuum drying oven at 90 °C for 24 hours to obtain a black blocky solid, which was then calcined in a muffle furnace at a heating rate of 2 °C / min to 500 °C for 4 hours. The calcined solid was ground and sieved to 60 mesh to obtain the copper-manganese-cerium-titanium catalyst. 0.15 g of the obtained copper-manganese-cerium-titanium catalyst powder and 252 μL of a 0.03 mol / L H₂PtCl₆·6H₂O solution (with a platinum loading of 1%) were dispersed in 30 mL of ultrapure water and stirred at room temperature for 2 hours to obtain solution C. 1 mL of a mixed solution of sodium borohydride and sodium hydroxide was added to solution C, and stirring was continued for 4 hours. The resulting solution was centrifuged and washed multiple times with ultrapure water until no Cl₂ was found. - The copper-manganese-cerium composite oxide catalyst supported on the noble metal platinum was obtained by vacuum drying at 60℃ for 24 hours.

[0061] Example 5

[0062] In this embodiment, a catalyst was prepared with approximately 89% TiO2 support, approximately 10% copper-manganese-cerium composite oxide, and approximately 1% platinum (a noble metal). The steps are as follows:

[0063] 8.2 g of tetrabutyl titanate, 5.76 g of glacial acetic acid, and 4.42 g of anhydrous ethanol were mixed in a molar ratio of 1:4:4 to obtain solution A. 0.056 g of Cu(NO3)2·3H2O, 0.23 g of Mn(NO3)2·4H2O, and 0.089 g of Ce(NO3)3·6H2O were dissolved in 20 ml of ultrapure water and stirred at room temperature and pressure for 1 hour to obtain solution B, in which the molar ratio of copper, manganese, and cerium was 1:4:1. Solution B was added dropwise to solution A, and the mixture was stirred at a constant speed in a water bath for 2 hours. The mixture was then heated to 80 °C to obtain a mixed gel. The gel was dried in a vacuum drying oven at 90 °C for 24 hours to obtain a black blocky solid, which was then calcined in a muffle furnace at a heating rate of 2 °C / min to 500 °C for 4 hours. The calcined solid was ground and sieved to 60 mesh to obtain the copper-manganese-cerium-titanium catalyst. 0.15 g of the obtained copper-manganese-cerium-titanium catalyst powder and 252 μL of a 0.03 mol / L H₂PtCl₆·6H₂O solution (with a platinum loading of 1%) were dispersed in 30 mL of ultrapure water and stirred at room temperature for 2 hours to obtain solution C. 1 mL of a mixed solution of sodium borohydride and sodium hydroxide was added to solution C, and stirring was continued for 4 hours. The resulting solution was centrifuged and washed multiple times with ultrapure water until no Cl₂ was found. - The copper-manganese-cerium composite oxide catalyst supported on the noble metal platinum was obtained by vacuum drying at 60℃ for 24 hours.

[0064] Example 6

[0065] In this embodiment, a catalyst was prepared with approximately 89% TiO2 support, approximately 10% copper-manganese-cerium composite oxide, and approximately 1% platinum (a noble metal). The steps are as follows:

[0066] 8.2 g tetrabutyl titanate, 0.72 g glacial acetic acid, and 2.21 g anhydrous ethanol were mixed in a molar ratio of 2:1:4 to obtain solution A. 0.056 g Cu(NO3)2·3H2O, 0.23 g Mn(NO3)2·4H2O, and 0.089 g Ce(NO3)3·6H2O were dissolved in 20 ml ultrapure water and stirred at room temperature and pressure for 1 hour to obtain solution B, in which the molar ratio of copper, manganese, and cerium was 1:4:1. Solution B was added dropwise to solution A, and the mixture was stirred at a constant speed in a water bath for 2 hours. The mixture was then heated to 80 °C to obtain a mixed gel. The gel was dried in a vacuum drying oven at 90 °C for 24 hours to obtain a black blocky solid, which was then calcined in a muffle furnace at a heating rate of 2 °C / min to 500 °C for 4 hours. The calcined solid was ground and sieved to 60 mesh to obtain the copper-manganese-cerium-titanium catalyst. 0.15 g of the obtained copper-manganese-cerium-titanium catalyst powder and 252 μL of a 0.03 mol / L H₂PtCl₆·6H₂O solution (with a platinum loading of 1%) were dispersed in 30 mL of ultrapure water and stirred at room temperature for 2 hours to obtain solution C. 1 mL of a mixed solution of sodium borohydride and sodium hydroxide was added to solution C, and stirring was continued for 4 hours. The resulting solution was centrifuged and washed multiple times with ultrapure water until no Cl₂ was found. - The copper-manganese-cerium composite oxide catalyst supported on the noble metal platinum was obtained by vacuum drying at 60℃ for 24 hours.

[0067] Comparative Example 1

[0068] 8.2 g of tetrabutyl titanate, 5.76 g of glacial acetic acid, and 8.84 g of anhydrous ethanol were mixed in a molar ratio of 1:4:8 to obtain solution A. 4.48 g of Ce(NO3)3·6H2O was dissolved in 20 ml of ultrapure water and stirred at room temperature and pressure for 1 hour to obtain solution B, in which the molar ratio of cerium to titanium was 1:2. Solution B was added dropwise to solution A, and the mixture was stirred at a constant speed in a water bath for 2 hours. The mixture was then heated to 80 °C to obtain a mixed gel. The gel was dried in a vacuum drying oven at 90 °C for 24 hours to obtain a black blocky solid, which was then calcined in a muffle furnace at a heating rate of 2 °C / min to 500 °C for 4 hours. The calcined solid was ground and sieved to 60 mesh to obtain the cerium-titanium catalyst. 0.15 g of the obtained cerium-titanium catalyst powder and 252 μL of H₂PtCl₆·6H₂O (with a platinum loading of 1%) were dispersed in 30 mL of ultrapure water and stirred at room temperature for 2 hours to obtain solution C. 1 mL of a mixed solution of sodium borohydride and sodium hydroxide was added to solution C, and stirring was continued for 4 hours. The resulting solution was centrifuged and washed multiple times with ultrapure water until no Cl₂ was found. - The platinum-supported cerium-titanium catalyst was obtained by vacuum drying at 60°C for 24 hours.

[0069] Figure 2 The figures show the efficiency curves of the catalysts in Example 1 and Comparative Example 1 catalyzing n-hexane. Figure 2 It can be seen that, compared with Example 1, the catalyst in Comparative Example 1 showed significantly reduced activity in catalyzing n-hexane.

[0070] Referring to Figures 4(a)(b)(c), X-ray photoelectron spectroscopy (XPS) characterization analysis shows that the introduction of copper and manganese elements causes the catalyst to exhibit Cu content. 2+ / Cu + With Mn 4+ / Mn 3+ The oxidation state distribution shows that this combination of valence states induces oxygen vacancy sites on the catalyst surface through electronic structure modulation. Peak fitting results from the O 1s XPS spectrum indicate that the synergistic effect of the copper-manganese components significantly increases the relative content of surface-active oxygen species, thereby promoting the formation of oxygen vacancy structures. When the noble metal platinum is introduced, through… Figure 5 Transmission electron microscopy (TEM) and XPS characterization confirmed that platinum species are uniformly dispersed in nanoparticle form and anchored at the aforementioned oxygen defect sites, forming highly efficient catalytic active centers. This multi-component synergistic array of active sites increases the density of accessible reactive sites per unit catalyst surface, providing more adsorption and activation sites for organic pollutant molecules, thereby significantly improving the intrinsic kinetic efficiency of the catalytic reaction. The optimization of this catalytic mechanism benefits from the regulatory effects of the copper-manganese components on the electronic structure and oxygen defect concentration, as well as the high dispersion of the noble metal platinum at the defect sites, forming a reaction pathway of "defect anchoring - noble metal activation - adsorption catalysis".

[0071] The above description, in conjunction with specific preferred embodiments, provides a further detailed explanation of the present invention and should not be construed as limiting the application of the invention to these descriptions. For those skilled in the art, appropriate deductions or substitutions can be made without departing from the core concept of the invention, and such deductions or substitutions still fall within the protection scope of the present invention.

Claims

1. A composite catalyst for low-temperature catalysis of organic pollutants, characterized in that, The catalyst uses TiO2 as a support and copper-manganese-cerium composite oxide and noble metal platinum as active components. The TiO2 support comprises 80% to 90% by weight; the copper-manganese-cerium composite oxide comprises 10% to 20% by weight; and the precious metal platinum comprises 0.1% to 1% by weight. In the copper-manganese-cerium composite oxide, the molar ratio of copper, manganese, and cerium is 1:(3~4):(0.5~1); copper, manganese, and cerium are distributed on the TiO2 surface; After reduction, platinum is distributed on the surface of the copper-manganese-cerium-titanium catalyst. Some of the platinum is dispersed in the form of single atoms on the Cu-Mn-O active sites, while the other part forms small nanoparticles.

2. The composite catalyst for low-temperature catalysis of organic pollutants according to claim 1, characterized in that, The TiO2 support was synthesized by the sol-gel method, has a mesoporous structure, a specific surface area of ​​100-110 m² / g, and an average pore size of 9-10 nm.

3. A method for preparing a composite catalyst for low-temperature catalysis of organic pollutants as described in any one of claims 1 to 2, characterized in that, Includes the following steps: (1) Take titanate, glacial acetic acid and anhydrous ethanol to mix to obtain solution A; take copper salt, manganese salt and cerium salt to dissolve in ultrapure water and stir to obtain solution B; add solution B dropwise to solution A, stir and heat in water bath to obtain mixed gel; (2) The mixed gel obtained in step (1) is dried, calcined, ground and sieved to obtain a copper manganese cerium titanium catalyst; (3) Add the copper-manganese-cerium-titanium catalyst obtained in step (2) to ultrapure water, and then add chloroplatinic acid solution dropwise while stirring; add a mixed solution of sodium borohydride and sodium hydroxide to the mixture and continue stirring; (4) The solution obtained in step (3) is centrifuged and washed multiple times with ultrapure water and then vacuum dried to obtain the composite catalyst.

4. The method for preparing a composite catalyst for low-temperature catalysis of organic pollutants according to claim 3, characterized in that, In step (1), The molar ratio of titanate, glacial acetic acid, and anhydrous ethanol is (1~2):(1~4):(4~8). The molar ratio of the metal elements in the copper salt, manganese salt, and cerium salt is 1:4:1; The water bath heating temperature is 60~80℃; The titanate is tetrabutyl titanate; the copper salt is at least one of CuSO4 and Cu(NO3)2·3H2O; the manganese salt is at least one of MnSO4·4H2O, Mn(NO3)2, and MnCO3; and the cerium salt is Ce(NO3)3·6H2O.

5. The method for preparing a composite catalyst for low-temperature catalysis of organic pollutants according to claim 3, characterized in that, In step (2), The drying conditions are 90~110℃, and the drying time is 20~30h; The calcination conditions are as follows: heating at 2~5℃ / min to 300~600℃ and calcining for 4~6 hours; The grinding and sieving process uses a mesh size of 60.

6. The method for preparing a composite catalyst for low-temperature catalysis of organic pollutants according to claim 3, characterized in that, In step (3), the volume of the sodium borohydride and sodium hydroxide mixed solution is 1~5 mL.

7. The method for preparing a composite catalyst for low-temperature catalysis of organic pollutants according to claim 3, characterized in that, In step (4), the washing refers to washing until no Cl is present. − Vacuum drying conditions are 60~80℃ for 24~30h.

8. The application of the composite catalyst for low-temperature catalysis of organic pollutants as described in claim 1 or 2 in the catalytic oxidation of organic pollutants.

9. The application according to claim 8, characterized in that, The organic pollutant is benzene or n-hexane.

10. The application according to claim 9, characterized in that, The treatment conditions for the catalytic oxidation of organic pollutants are as follows: the concentration of organic pollutants in the mixed gas is 400 ppm, the reaction temperature is 30~300℃, the simulated temperature rise rate is 2℃ / min, and the ignition temperature is 100~125℃.

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