Pt-based coating type catalyst as well as preparation method and application thereof

Abstract

The invention relates to the technical field of novel environment-friendly materials, in particular to a Pt-based coating type catalyst as well as a preparation method and application thereof. The preparation method of the Pt-based coating type catalyst comprises the following steps: carrying out ultrasonic cleaning on a coating base material, then drying the coating base material, and then immersing the coating base material in an etching solution for etching and cleaning; the etched coating base material is sequentially soaked in a catalytic component solution and ammonia water, and a coating base material containing catalytic gel is obtained; and calcining the coating base material containing the catalytic gel to obtain the Pt-based coating type catalyst. The preparation process is simple, the catalyst and the base material are prepared synchronously, the catalyst is combined with the base material through chemical reaction, the binding strength is high, the secondary loading process is avoided, and the catalyst preparation and use process is shortened. The Pt-based coating type catalyst disclosed by the invention is integrally in a fibrofelt shape, and can be directly used for removing various pollutants (PM2.5 and VOCs).

Description

Technical Field

[0001] The present invention relates to the technical field of new environmental protection materials, and particularly relates to a Pt-based coated catalyst, a preparation method thereof, and an application thereof. Background Art

[0002] The Pt-based catalyst takes Pt as the core active component and realizes the catalytic function through the synergistic effect with other metals, carriers or functional groups. Due to its unique physical and chemical properties, the Pt-based catalyst shows significant advantages in the fields of resource recycling, green process adaptation, and environmental protection waste gas treatment. With its high catalytic activity, excellent stability, renewable property, and flexible structure design space, the Pt-based catalyst has become the core material in the fields of energy conversion, environmental governance, etc.

[0003] At present, the research on Pt-based catalysts mainly focuses on formula research and process research. The prepared Pt-based catalysts are mostly powders or particles, and the catalysts need to be loaded with other materials during use. In the field of air pollution control, it is often necessary to remove multiple pollutants in the air simultaneously, such as PM2.5, formaldehyde and other VOCs gases. The existing Pt-based catalysts need to be processed by secondary loading to achieve the purpose of removing multiple pollutants. The process is complex, and after secondary loading, the binding force between the catalyst and the substrate is low, and it is easy to fall off, resulting in the loss of the catalyst. Summary of the Invention

[0004] The purpose of the present invention is to provide a Pt-based coated catalyst, a preparation method thereof, and an application thereof, which have a simple preparation process, the catalyst and the substrate are prepared synchronously, the catalyst is combined with the substrate through a chemical reaction, the binding fastness is strong, the secondary loading process is avoided, and the catalyst preparation and use process is shortened.

[0005] To achieve the above purpose, the present invention provides the following solutions:

[0006] One of the technical solutions of the present invention, a preparation method of a Pt-based coated catalyst, comprises the following steps:

[0007] Ultrasonically clean the coated substrate and then dry it to obtain the dried coated substrate;

[0008] Immerse the dried coated substrate in an etching solution for etching, and then wash it to obtain the etched coated substrate;

[0009] Immerse the etched coated substrate in a catalytic component solution and ammonia water in sequence to obtain a coated substrate containing catalytic gel;

[0010] Calcine the coated substrate containing catalytic gel to obtain the Pt-based coated catalyst;

[0011] The catalytic component solution is prepared by adding chloroplatinic acid solution, tetrabutyl titanate solution and potassium permanganate solution into ethanol, mixing them evenly and adjusting the pH to 3-5.

[0012] In a preferred embodiment of the present invention, the coated substrate is a polyester wet non-woven fabric; the coated substrate is ultrasonically cleaned in a mixed solution with a volume ratio of ethanol to water of 3:8 for 30-50 min; the drying temperature is 50-80 °C and the time is 3-8 h.

[0013] In a preferred embodiment of the present invention, the etching solution is a phenol solution with a concentration of 2 wt%-10 wt%.

[0014] In a preferred embodiment of the present invention, the etching time is 8-30 min.

[0015] In a preferred embodiment of the present invention, the etched coated substrate is successively immersed in the catalytic component solution and ammonia water for 10-20 min and 5-10 min respectively.

[0016] When the etched coated substrate is immersed in the catalytic component solution, stirring is also carried out at 150 rpm.

[0017] In a preferred embodiment of the present invention, the calcination is specifically: calcining at 150-400 °C for 1-5 h in a nitrogen atmosphere.

[0018] In a preferred embodiment of the present invention, the concentration of the chloroplatinic acid solution is 5-30 mg / L; the concentration of the tetrabutyl titanate solution is 35-60 g / L; the concentration of the potassium permanganate solution is 10-20 g / L; the volume ratio of the chloroplatinic acid solution, tetrabutyl titanate solution, potassium permanganate solution to ethanol is 7:31:19:37; further preferably, the concentration of the chloroplatinic acid solution is 5-20 mg / L; the concentration of the tetrabutyl titanate solution is 48 g / L; the concentration of the potassium permanganate solution is 13 g / L; the volume ratio of the chloroplatinic acid solution, tetrabutyl titanate solution, potassium permanganate solution to ethanol is 7:31:19:37.

[0019] The second technical solution of the present invention is a Pt-based coated catalyst prepared by the above preparation method.

[0020] In a preferred embodiment of the present invention, the Pt-based coated catalyst is in the form of a fiber felt, composed of a coated substrate and a catalytic component, with a thickness of 2-4 mm and a grammage of 120-200 g / m 2; The coated substrate is carbon fiber, the porosity of the carbon fiber is greater than 40%, the pore diameter is 0.5 - 10 nm, the fiber length is 3 - 10 mm, and the fiber diameter is 100 - 500 μm; the catalytic component accounts for 20% - 40% of the total mass of the catalyst, and the catalytic component is a Pt-based material; by mass percentage, the proportion of Pt in the Pt-based material is 10% - 20%, the proportion of TiO2 is 50% - 60%, and the proportion of MnO2 is 30% - 40%.

[0021] The third technical solution of the present invention is the application of the above-mentioned Pt-based coated catalyst in removing PM2.5 or VOCs gas.

[0022] The present invention discloses the following technical effects:

[0023] In the present invention, a solution of the catalyst component is coated on the substrate raw material, and then a catalyst gel is generated on the substrate raw material through a chemical reaction. The substrate is carbonized to form activated carbon fibers by high-temperature heating and calcination, and the catalyst gel is calcined to generate the catalyst active component. The two are tightly combined to prevent the catalyst from falling off during use. The substrate raw material used forms numerous pores through etching, increasing the porosity after carbonization, and fresh catalyst attachment sites are formed on the surface of the substrate raw material through etching, enhancing the catalyst attachment performance.

[0024] The Pt-based coated catalyst prepared by the method of the present invention is in the form of a fiber felt as a whole and can be directly used for removing various pollutants. The activated carbon fibers can intercept the particulate matter components in the gas, and at the same time, the pores of the activated carbon fibers can adsorb VOCs gases such as formaldehyde. The adsorbed VOCs gases are slowly released and come into contact with the catalytic component, and are catalytically decomposed by the Pt-based catalyst. The transition metals Ti and Mn in the catalytic component can enhance the catalytic activity of the Pt catalyst and enhance the overall catalytic performance of the catalyst. Description of the Drawings

[0025] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for use in the embodiments. Obviously, the drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0026] Figure 1 It is a photograph of the appearance of the Pt-based coated catalyst prepared for Example 2.

[0027] Figure 2 It is an electron microscope photograph of the polyester wet non-woven fabric used in Example 2 of the present invention.

[0028] Figure 3 It is an electron microscope photograph of the catalyst before calcination in Example 2 (i.e., the coated substrate containing catalytic gel obtained in Step 4).

[0029] Figure 4 It is the electron microscope photograph of the catalyst after calcination in Example 2 (i.e., the Pt-based coated catalyst).

[0030] Figure 5 It is the catalytic performance of the Pt-based coated catalyst prepared in Example 2 for formaldehyde.

[0031] Figure 6 It is the PM2.5 filtration efficiency of the Pt-based coated catalyst prepared in Example 2. Detailed implementation manners

[0032] Now, various exemplary implementation manners of the present invention will be described in detail. This detailed description should not be considered as a limitation to the present invention, but should be understood as a more detailed description of certain aspects, characteristics and implementation schemes of the present invention.

[0033] It should be understood that the terms described in the present invention are only for describing particular implementation manners and are not used to limit the present invention. Additionally, for the numerical ranges in the present invention, it should be understood that each intermediate value between the upper and lower limits of the range is also specifically disclosed. Any intermediate value within any stated value or stated range, as well as each smaller range between any other stated value or intermediate value within the stated range, is also included in the present invention. The upper and lower limits of these smaller ranges may be independently included or excluded from the range.

[0034] Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by those of ordinary skill in the art to which the present invention pertains. Although the present invention only describes preferred methods and materials, any methods and materials similar or equivalent to those described herein can also be used in the implementation or testing of the present invention. All documents mentioned in this specification are incorporated by reference to disclose and describe the methods and / or materials related to the documents. In case of conflict with any incorporated document, the content of this specification shall prevail.

[0035] Without departing from the scope or spirit of the present invention, various improvements and changes can be made to the specific implementation manners of the specification of the present invention, which are obvious to those skilled in the art. Other implementation manners obtained from the specification of the present invention are obvious to those skilled in the art. The specification and examples of the present invention are only exemplary.

[0036] Regarding the use of "comprising", "including", "having", "containing", etc. in this article, they are all open-ended terms, meaning including but not limited to.

[0037] The "%" described in the present invention represents mass percentage unless otherwise specified.

[0038] The present invention discloses a Pt-based coated catalyst and a preparation method thereof. The preparation process is simple, the catalyst is prepared synchronously with the substrate, and the catalyst is combined with the substrate through a chemical reaction, with strong bonding strength, avoiding the secondary loading process and shortening the preparation and use process of the catalyst. The Pt-based coated catalyst disclosed by the present invention is in the shape of a fiber felt as a whole and can be directly used for the removal of various pollutants. The activated carbon fibers can intercept the particulate matter components in the gas, and at the same time, the pores of the activated carbon fibers can adsorb VOCs gases such as formaldehyde. The adsorbed VOCs gases are slowly released to contact with the catalytic components and are catalytically decomposed by the Pt-based catalyst. The transition metals Ti and Mn in the catalytic components can enhance the catalytic activity of the Pt catalyst and enhance the overall catalytic performance of the catalyst.

[0039] For the technical solutions described in the present invention, unless otherwise specified, they are all conventional solutions in the art. The reagents or raw materials used, unless otherwise specified, are all purchased from commercial channels or have been publicly disclosed.

[0040] The polyester wet non-woven fabric used in the examples of the present invention was purchased from Shandong Runyao Environmental Protection Technology Co., Ltd., and the main parameter specifications are 30*30*2.5 cm.

[0041] The dilute ammonia water used in the examples of the present invention is specifically ammonia water with a volume fraction of 5%.

[0042] The solvents of the chloroplatinic acid solution, tetrabutyl titanate solution and potassium permanganate solution used in the examples of the present invention are all water.

[0043] The test methods involved in the present invention are as follows:

[0044] Catalytic efficiency of the Pt-based coated catalyst for formaldehyde:

[0045] Test method: Formaldehyde gas is generated by bubbling paraformaldehyde through the gas path, and a fixed-bed reactor is used to load the catalyst for the formaldehyde purification performance test. The inlet and outlet gases are accurately measured for formaldehyde concentration using a portable formaldehyde detector. The test method refers to GB / T 23761-2020.

[0046] Calculation formula for formaldehyde catalytic efficiency: Formaldehyde catalytic efficiency = (C 进口，甲醛 -C 出口，甲醛 ) / C 进口，甲醛 *100%

[0047] Interception efficiency of the Pt-based coated catalyst for PM2.5 particulate matter:

[0048] An aerosol generator is used to generate standard PM2.5 particles (particle size distribution 0.3 - 2.5 μm). The PM2.5 is introduced into a closed pipeline (equipped with a filter material fixture to ensure no bypass leakage). An optical particle counter (OPC) is used to monitor the number concentration of PM2.5 entering and leaving the closed pipeline in real time. The test method refers to GB / T 18801 - 2015.

[0049] The calculation formula for the interception efficiency of PM2.5 particles: Interception efficiency of PM2.5 particles = C 进口，PM2.5 - C 出口，PM2.5 ) / C 进口，PM2.5 * 100%

[0050] The technical solutions provided by the present invention will be described in detail below in conjunction with the embodiments, but they should not be construed as limiting the protection scope of the present invention.

[0051] Example 1

[0052] A preparation method of a Pt-based coated catalyst is as follows:

[0053] Step 1: Ultrasonically clean the coated substrate (polyester wet non-woven fabric) in an ethanol-aqueous solution (ethanol: water volume ratio is 3:8) at a power of 100 W (60 - 120 W is acceptable) for 35 min. After cleaning, dry it at 70 °C for 5 h (drying at 50 - 80 °C for 3 - 8 h is acceptable) and then set aside;

[0054] Step 2: Immerse the coated substrate dried in Step 1 in a phenol solution with a mass concentration of 8% (solvent is ethanol) for 30 min. After immersion, take it out and wash it with clean water and set aside;

[0055] Step 3: Add 7 mL of chloroplatinic acid solution with a mass concentration of 5 mg / L, 31 mL of tetrabutyl titanate solution with a mass concentration of 48 g / L, and 19 mL of potassium permanganate solution with a mass concentration of 13 g / L to 37 mL of ethanol and stir well. Add nitric acid to adjust the pH to 4.3 to obtain a catalytic component solution;

[0056] Step 4: Immerse the etched coated substrate prepared in Step 2 into the catalytic component solution prepared in Step 3. After stirring and soaking at 150 rpm for 10 min, take out the coated substrate and immerse it in dilute ammonia water for 10 min to form a catalytic gel on the coated substrate in an alkaline environment;

[0057] Step 5: Calcinate the coated substrate containing the catalytic gel prepared in Step 4 at 300 °C for 1 h in a nitrogen atmosphere to obtain a Pt-based coated catalyst.

[0058] The Pt-based coated catalyst prepared in this example is in the form of a fiber felt, with a thickness of 2 mm and a grammage of 120 g / m 2, consisting of a coated substrate and a catalytic component; the coated substrate is carbon fiber, the porosity of the carbon fiber is 45%, the pore diameter is 0.5 nm, the fiber length is 3 mm, and the fiber diameter is 100 μm; the catalytic component accounts for 40% of the total mass of the catalyst, the catalytic component is a Pt-based material, the proportion of Pt in the Pt-based material is 15 wt%, the proportion of TiO2 is 51 wt%, and the proportion of MnO2 is 34 wt%.

[0059] The Pt-based coated catalyst prepared in this example has a formaldehyde catalytic efficiency of 80% and a PM2.5 particulate interception efficiency of 90%.

[0060] Example 2

[0061] A method for preparing a Pt-based coated catalyst comprises the following steps:

[0062] Step 1: The same as Step 1 of Example 1;

[0063] Step 2: Immerse the dried coated substrate obtained in Step 1 in a phenol solution with a mass concentration of 8% (the solvent is ethanol) for 15 min, take it out and wash it with clear water after soaking, and set it aside for later use;

[0064] Step 3: Add 7 mL of chloroplatinic acid solution with a mass concentration of 5 mg / L, 31 mL of tetrabutyl titanate solution with a mass concentration of 48 g / L, and 19 mL of potassium permanganate solution with a mass concentration of 13 g / L to 37 mL of ethanol, stir well, and adjust the pH to 4.3 with nitric acid to obtain a catalytic component solution;

[0065] Step 4: Immerse the etched coated substrate prepared in Step 2 into the catalytic component solution prepared in Step 3. After stirring and soaking at 150 rpm for 10 min, take out the coated substrate and immerse it in dilute ammonia water for 10 min to form a catalytic gel of the catalytic component on the coated substrate under an alkaline environment;

[0066] Step 5: Calcinate the coated substrate containing the catalytic gel obtained in Step 4 at 300 °C for 1 h under a nitrogen atmosphere to obtain a Pt-based coated catalyst.

[0067] The Pt-based coated catalyst prepared in this example is in the form of a fiber felt, with a thickness of 4 mm and a grammage of 200 g / m 2 , consisting of a coated substrate and a catalytic component; the coated substrate is carbon fiber, the porosity of the carbon fiber is 50%, the pore diameter is 10 nm, the fiber length is 10 mm, and the fiber diameter is 500 μm; the catalytic component accounts for 20% of the total mass of the catalyst, the catalytic component is a Pt-based material, the proportion of Pt in the Pt-based material is 10%, the proportion of TiO2 is 55%, and the proportion of MnO2 is 35%.

[0068] The Pt-based coated catalyst prepared in this example has a formaldehyde catalytic efficiency of 90% and a PM2.5 particulate interception efficiency of 95%.

[0069] Example 3

[0070] A preparation method of a Pt-based coated catalyst is as follows:

[0071] Step 1: The same as Step 1 of Example 1;

[0072] Step 2: Immerse the coated substrate dried in Step 1 in a phenol solution with a mass concentration of 8% (the solvent is ethanol) for 8 min. After the immersion, take it out and wash it with clear water for standby;

[0073] Step 3: Add 7 mL of chloroplatinic acid solution with a mass concentration of 5 mg / L, 31 mL of tetrabutyl titanate solution with a mass concentration of 48 g / L, and 19 mL of potassium permanganate solution with a mass concentration of 13 g / L to 37 mL of ethanol, stir well, and add nitric acid to adjust the pH to 4.3 to obtain a catalytic component solution;

[0074] Step 4: Immerse the etched coated substrate prepared in Step 2 into the catalytic component solution prepared in Step 3. After stirring and infiltrating at 150 rpm for 10 min, take out the coated substrate and immerse it in dilute ammonia water for 10 min to form a catalytic gel on the coated substrate under an alkaline environment;

[0075] Step 5: Calcinate the coated substrate containing the catalytic gel prepared in Step 4 at 300 °C for 1 h under a nitrogen atmosphere to obtain a Pt-based coated catalyst.

[0076] The Pt-based coated catalyst prepared in this example is in the form of a fiber felt, with a thickness of 4 mm and a grammage of 200 g / m 2 , and it is composed of a coated substrate and a catalytic component; the coated substrate is carbon fiber, the porosity of the carbon fiber is 50%, the pore diameter is 10 nm, the fiber length is 10 mm, and the fiber diameter is 500 μm; the catalytic component accounts for 20% of the total mass of the catalyst, the catalytic component is a Pt-based material, the proportion of Pt in the Pt-based material is 15%, the proportion of TiO2 is 50%, and the proportion of MnO2 is 35%.

[0077] The Pt-based coated catalyst prepared in this example has a catalytic efficiency for formaldehyde of 85% and a PM2.5 particulate interception efficiency of 95%.

[0078] Comparative Example 1

[0079] The difference from Example 2 is only that the phenol solution with a mass concentration of 8% (the solvent is ethanol) in Step 2 is replaced with a tetrachloroethane solution with a mass concentration of 8% (the solvent is ethanol); the other steps and parameters are the same as those in Example 2.

[0080] The Pt-based coated catalyst prepared in this comparative example is in the form of a fiber felt, with a thickness of 4 mm and a grammage of 200 g / m2 , which is composed of a coated substrate and a catalytic component; the coated substrate is carbon fiber, the porosity of the carbon fiber is 50%, the pore diameter is 10 nm, the fiber length is 10 mm, and the fiber diameter is 500 μm; the catalytic component accounts for 20% of the total mass of the catalyst, the catalytic component is a Pt-based material, the proportion of Pt in the Pt-based material is 12%, the proportion of TiO2 is 55%, the proportion of MnO2 is 33%, and the remaining components are the coating matrix (carbon fiber).

[0081] The highest formaldehyde catalytic efficiency of the Pt-based coated catalyst prepared in this comparative example is 75%, and the highest PM2.5 particulate interception efficiency is 73%.

[0082] Comparative Example 2

[0083] The difference from Example 2 is only that the phenol solution with a mass concentration of 8% (solvent is ethanol) in Step 2 is replaced by a benzene solution with a mass concentration of 8% (solvent is ethanol); the remaining steps and parameters are the same as those in Example 2.

[0084] The Pt-based coated catalyst prepared in this comparative example is in the form of a fiber felt, with a thickness of 4 mm and a grammage of 200 g / m 2 , which is composed of a coated substrate and a catalytic component; the coated substrate is carbon fiber, the porosity of the carbon fiber is 50%, the pore diameter is 10 nm, the fiber length is 10 mm, and the fiber diameter is 500 μm; the catalytic component accounts for 20% of the total mass of the catalyst, the catalytic component is a Pt-based material, the proportion of Pt in the Pt-based material is 10%, the proportion of TiO2 is 52%, and the proportion of MnO2 is 38%.

[0085] The highest formaldehyde catalytic efficiency of the Pt-based coated catalyst prepared in this comparative example is 70%, and the highest PM2.5 particulate interception efficiency is 70%.

[0086] Figure 1 is a photograph of the appearance of the Pt-based coated catalyst prepared in Example 2. From Figure 1 it can be seen that the active components are evenly dispersed on the surface of the carrier and there is no shedding phenomenon, indicating that the prepared Pt-based coated catalyst has a high binding ability to the powder.

[0087] Figure 2 is an electron microscope photograph of the polyester wet-laid nonwoven fabric used in Example 2 of the present invention. From Figure 2 it can be seen that the surface of the carrier without loaded active powder is smooth and there is no obvious rough interface.

[0088] Figure 3 is an electron microscope photograph of the catalyst before calcination in Example 2 (i.e., the coated substrate containing the catalytic gel obtained in Step 4). From Figure 3 it can be seen that after the active powder is loaded on the surface of the carrier, an obvious rough interface is formed, indicating that the active component is successfully combined with the carrier.

[0089] Figure 4 It is the electron micrograph of the calcined catalyst (i.e., Pt-based coated catalyst) in Example 2. From Figure 4 it can be seen that the interface combination effect occurs between the carrier and the active powder after calcination, and the active powder is strongly bonded to the carrier, which can effectively prevent the active powder on the carrier surface from falling off, verifying that the prepared coated catalyst has a high bonding strength.

[0090] Figure 5 It is the catalytic performance of the Pt-based coated catalyst prepared in Example 2 for formaldehyde. From Figure 5 it can be seen that at room temperature (20±5°C), the purification efficiency of 5-10 ppm formaldehyde can reach more than 90%, realizing the high-efficiency purification of formaldehyde.

[0091] Figure 6 It is the PM2.5 filtration efficiency of the Pt-based coated catalyst prepared in Example 2. From Figure 6 it can be seen that for PM2.5 with an average inlet concentration of about 220 μg / m 3 ³, the prepared Pt-based coated catalyst can achieve a particulate interception efficiency of more than 95% within 100 min.

[0092] The above-described embodiments are only used to describe the preferred mode of the present invention, and do not limit the scope of the present invention. Without departing from the design spirit of the present invention, various deformations and improvements made by those of ordinary skill in the art to the technical solutions of the present invention should all fall within the protection scope determined by the claims of the present invention.

Claims

1. A preparation method of a Pt-based coated catalyst, characterized in that, It includes the following steps: Ultrasonically clean the coated substrate and then dry it to obtain the dried coated substrate; Immerse the dried coated substrate in an etching solution for etching, and then wash it to obtain the etched coated substrate; Immerse the etched coated substrate successively in a catalytic component solution and ammonia water to obtain a coated substrate containing catalytic gel; Calcine the coated substrate containing catalytic gel to obtain the Pt-based coated catalyst; The catalytic component solution is prepared by adding a chloroplatinic acid solution, a tetrabutyl titanate solution, and a potassium permanganate solution to ethanol, mixing them evenly, and adjusting the pH to 3-5.

2. The preparation method of the Pt-based coated catalyst according to claim 1, wherein The coated substrate is a polyester wet non-woven fabric; the coated substrate is ultrasonically cleaned in a mixed solution with a volume ratio of ethanol to water of 3:8 for 30-50 min; the drying temperature is 50-80 °C and the time is 3-8 h.

3. The preparation method of the Pt-based coated catalyst according to claim 1, characterized in that, The etching solution is a phenol solution with a concentration of 2 wt%-10 wt%.

4. The preparation method of the Pt-based coated catalyst according to claim 1, characterized in that, The etching time is 8-30 min.

5. The preparation method of the Pt-based coated catalyst according to claim 1, characterized in that, The times for immersing the etched coated substrate successively in the catalytic component solution and ammonia water are 10-20 min and 5-10 min, respectively.

6. The preparation method of the Pt-based coated catalyst according to claim 1, wherein The calcination is specifically: calcining at 150-400 °C for 1-5 h under a nitrogen atmosphere.

7. The preparation method of the Pt-based coated catalyst according to claim 1, characterized in that, The concentration of the chloroplatinic acid solution is 5-30 mg / L; the concentration of the tetrabutyl titanate solution is 35-60 g / L; the concentration of the potassium permanganate solution is 10-20 g / L; the volume ratio of the chloroplatinic acid solution, the tetrabutyl titanate solution, the potassium permanganate solution to ethanol is 7∶31∶19∶37.

8. The Pt-based coated catalyst prepared by the preparation method according to any one of claims 1-7.

9. The Pt-based coated catalyst according to claim 8, wherein The Pt-based coated catalyst is in the form of a fibrous felt, composed of a coating substrate and a catalytic component, with a thickness of 2-4 mm and a grammage of 120-200 g / m 2 ; the coating substrate is carbon fiber, the porosity of the carbon fiber is greater than 40%, the pore diameter is 0.5-10 nm, the fiber length is 3-10 mm, and the fiber diameter is 100-500 μm; the catalytic component accounts for 20%-40% of the total mass of the catalyst, and the catalytic component is a Pt-based material; by mass percentage, the proportion of Pt in the Pt-based material is 10%-20%, the proportion of TiO2 is 50%-60%, and the proportion of MnO2 is 30%-40%.

10. The application of the Pt-based coated catalyst according to claim 8 or 9 in removing PM2.5 or VOCs gases.

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