Pt-based coated catalyst, its preparation method and use

Abstract

The present application relates to the technical field of environmental protection new material, particularly relates to a Pt-based coating type catalyst and a preparation method and application thereof. The preparation method of the Pt-based coating type catalyst comprises the following steps: after the coating substrate is ultrasonically cleaned and dried, then immersed in an etching liquid for etching and cleaning; the coating substrate after etching is immersed in a catalytic component solution and ammonia water in sequence to obtain a coating substrate containing catalytic gel; the coating substrate containing catalytic gel is calcined to obtain the Pt-based coating type catalyst. The present application has the advantages of simple preparation process, synchronous preparation of the catalyst and the substrate, combination of the catalyst and the substrate through chemical reaction, strong combination strength, avoidance of secondary loading process and shortening of the catalyst preparation and use process. The Pt-based coating type catalyst disclosed by the present application is in the form of a fibrous felt and can be directly used for removal of various pollutants (PM2.5, VOCs).

Description

Technical Field

[0001] This invention relates to the field of environmentally friendly new materials technology, and in particular to a Pt-based coated catalyst, its preparation method, and its application. Background Technology

[0002] Pt-based catalysts are catalysts that use Pt as the core active component and achieve catalytic function through synergistic effects with other metals, supports, or functional groups. Due to their unique physicochemical properties, Pt-based catalysts have shown significant advantages in areas such as resource recycling, green process adaptation, and environmental waste gas treatment. With their high catalytic activity, excellent stability, renewability, and flexible structural design space, Pt-based catalysts have become core materials in energy conversion and environmental governance.

[0003] Current research on Pt-based catalysts mainly focuses on formulation and process research. The prepared Pt-based catalysts are mostly in the form of powder or granules. 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 at the same time, such as PM2.5, formaldehyde and other VOCs. Existing Pt-based catalysts need to undergo secondary loading processing to achieve the purpose of removing multiple pollutants. The process is complicated, and the catalyst has low bonding force with the substrate after secondary loading, making it easy to fall off and causing catalyst loss. Summary of the Invention

[0004] The purpose of this invention is to provide a Pt-based coated catalyst, its preparation method, and its application. The catalyst has the advantages of simple preparation process, simultaneous preparation of catalyst and substrate, strong bonding between catalyst and substrate through chemical reaction, avoidance of secondary loading process, and shortening of catalyst preparation and use process.

[0005] To achieve the above objectives, the present invention provides the following solution:

[0006] One of the technical solutions of this invention is a method for preparing a Pt-based coated catalyst, comprising the following steps:

[0007] The coated substrate is ultrasonically cleaned and then dried to obtain the dried coated substrate.

[0008] The dried coating substrate is immersed in an etching solution for etching, and then cleaned to obtain the etched coating substrate.

[0009] The etched coating substrate is sequentially immersed in a catalytic component solution and ammonia water to obtain a coating substrate containing catalytic gel;

[0010] The coating substrate containing the catalytic gel was calcined 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 to ethanol, mixing them, and adjusting the pH to 3-5.

[0012] In a preferred embodiment of the present invention, the coating substrate is a wet-laid polyester nonwoven fabric; the coating substrate is ultrasonically cleaned in a mixed solution of ethanol:water with a volume ratio of 3:8 for 30-50 minutes; the drying temperature is 50-80℃ and the time is 3-8 hours.

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

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

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

[0016] The etched coated substrate was immersed in the catalytic component solution and stirred at 150 rpm.

[0017] In a preferred embodiment of the present invention, the calcination specifically involves calcining at 150-400°C for 1-5 hours under 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; and the volume ratio of the chloroplatinic acid solution, tetrabutyl titanate solution, potassium permanganate solution, and ethanol is 7:31:19:37. More 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; and the volume ratio of the chloroplatinic acid solution, tetrabutyl titanate solution, potassium permanganate solution, and ethanol is 7:31:19:37.

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

[0020] In a preferred embodiment of the present invention, the Pt-based coated catalyst is a fibrous felt, composed of a coating substrate and catalytic components, with a thickness of 2-4 mm and a basis weight of 120-200 g / m³. 2The coating substrate is carbon fiber with a porosity greater than 40%, a pore size of 0.5-10 nm, a fiber length of 3-10 mm, and a fiber diameter of 100-500 μm. The catalytic component accounts for 20%-40% of the total mass of the catalyst and is a Pt-based material. By mass percentage, the Pt-based material contains 10%-20% Pt, 50%-60% TiO2, and 30%-40% MnO2.

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

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

[0023] This invention involves coating a catalyst solution onto a substrate material, followed by a chemical reaction to generate a catalyst gel on the substrate. High-temperature calcination then carbonizes the substrate, forming activated carbon fibers. The calcined catalyst gel generates the active catalyst components, and the two are tightly bonded together, preventing catalyst detachment during use. The substrate material is etched to create numerous pores, increasing its porosity after carbonization. This etching process also creates fresh catalyst adhesion sites on the substrate surface, enhancing catalyst adhesion performance.

[0024] The Pt-based coated catalyst prepared by the method of this invention is in the form of a fibrous felt and can be used directly to remove various pollutants. The activated carbon fiber can intercept particulate matter in the gas, and the pores of the activated carbon fiber can adsorb VOCs such as formaldehyde. The adsorbed VOCs are slowly released and come into contact with the catalytic components, where they 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 improve the overall catalytic performance of the catalyst. Attached Figure Description

[0025] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0026] Figure 1 Photographs showing the appearance of the Pt-based coated catalyst prepared in Example 2.

[0027] Figure 2 This is an electron microscope image of the polyester wet-laid nonwoven fabric used in Example 2 of the present invention.

[0028] Figure 3 The image shows an electron microscope (EM) image of the catalyst before calcination in Example 2 (i.e., the coated substrate containing catalytic gel obtained in step four).

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

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

[0031] Figure 6 The PM2.5 filtration efficiency of the Pt-based coated catalyst prepared in Example 2. Detailed Implementation

[0032] 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.

[0033] 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. Any stated value or intermediate value within a stated range, as well as each smaller range between 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.

[0034] 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.

[0035] 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.

[0036] 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.

[0037] Unless otherwise specified, the "%" mentioned in this invention refers to a percentage by mass.

[0038] This invention discloses a Pt-based coated catalyst and its preparation method. The preparation process is simple, with the catalyst and substrate prepared simultaneously. The catalyst bonds to the substrate through a chemical reaction, resulting in strong bonding and avoiding secondary loading processes, thus shortening the catalyst preparation and usage process. The Pt-based coated catalyst disclosed in this invention is integrally fibrous felt-like and can be directly used to remove various pollutants. The activated carbon fibers can intercept particulate matter in the gas, while the pores of the activated carbon fibers can adsorb VOCs such as formaldehyde. The adsorbed VOCs are slowly released and come into contact with the catalytic components, where they 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, thereby enhancing the overall catalytic performance of the catalyst.

[0039] Unless otherwise specified, the technical solutions described in this invention are all conventional solutions in the field, and the reagents or raw materials used are all purchased from commercial channels or are publicly available unless otherwise specified.

[0040] The polyester wet-laid nonwoven fabric used in this embodiment of the invention was purchased from Shandong Runyao Environmental Protection Technology Co., Ltd., and its main parameters are 30*30*2.5cm.

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

[0042] In the embodiments of the present invention, the solvents for chloroplatinic acid solution, tetrabutyl titanate solution and potassium permanganate solution are all water.

[0043] The testing methods involved in this invention are as follows:

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

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

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

[0047] Pt-based coated catalyst PM2.5 particulate matter interception efficiency:

[0048] Standard PM2.5 particles (0.3-2.5μm in size) are generated using an aerosol generator and introduced into a sealed duct (with built-in filter material clamps to ensure no bypass leakage). The number and concentration of PM2.5 entering and leaving the sealed duct are monitored in real time using an oral particle counter (OPC). The test method is in accordance with GB / T 18801-2015.

[0049] The formula for calculating PM2.5 particulate matter interception efficiency is: PM2.5 particulate matter interception efficiency = 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 with reference to the embodiments, but they should not be construed as limiting the scope of protection of the present invention.

[0051] Example 1

[0052] A method for preparing a Pt-based coated catalyst, comprising the following steps:

[0053] Step 1: Clean the coated substrate (wet polyester nonwoven fabric) with ethanol-water solution (ethanol:water volume ratio of 3:8) for 35 minutes using ultrasonic cleaning at 100W (60-120W is also acceptable). After cleaning, dry at 70℃ for 5 hours (50-80℃ for 3-8 hours is also acceptable) and set aside for later use.

[0054] Step 2: Immerse the coated substrate dried in Step 1 in an 8% phenol solution (ethanol as solvent) for 30 minutes. After immersion, remove it and rinse it with clean water for later use.

[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 thoroughly. Add nitric acid to adjust the pH to 4.3 to obtain the catalytic component solution.

[0056] Step 4: Immerse the etched coating substrate obtained in Step 2 into the catalytic component solution prepared in Step 3. Stir and soak at 150 rpm for 10 min. Then, take out the coating substrate and immerse it in dilute ammonia water for 10 min, so that the catalytic component can form a catalytic gel on the coating substrate in an alkaline environment.

[0057] Step 5: Calcine the coating substrate containing catalytic gel obtained in Step 4 at 300°C for 1 hour under a nitrogen atmosphere to obtain a Pt-based coated catalyst.

[0058] The Pt-based coated catalyst prepared in this embodiment is a fibrous felt with a thickness of 2 mm and a basis weight of 120 g / m². 2It consists of a coating substrate and a catalytic component; the coating substrate is carbon fiber with a porosity of 45%, a pore size of 0.5 nm, a fiber length of 3 mm, and a fiber diameter of 100 μm; the catalytic component accounts for 40% of the total mass of the catalyst, and the catalytic component is a Pt-based material, in which Pt accounts for 15 wt%, TiO2 accounts for 51 wt%, and MnO2 accounts for 34 wt%.

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

[0060] Example 2

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

[0062] Step 1: Same as Step 1 in Example 1;

[0063] Step 2: Immerse the coated substrate dried in Step 1 in an 8% phenol solution (ethanol as solvent) for 15 minutes. After immersion, remove it and rinse it with clean water 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 and stir thoroughly. Add nitric acid to adjust the pH to 4.3 to obtain the catalytic component solution.

[0065] Step 4: Immerse the etched coating substrate obtained in Step 2 into the catalytic component solution prepared in Step 3. Stir and soak at 150 rpm for 10 min. Then, take out the coating substrate and immerse it in dilute ammonia water for 10 min, so that the catalytic component can form a catalytic gel on the coating substrate in an alkaline environment.

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

[0067] The Pt-based coated catalyst prepared in this embodiment is a fibrous felt with a thickness of 4 mm and a basis weight of 200 g / m². 2 It consists of a coating substrate and a catalytic component; the coating substrate is carbon fiber with a porosity of 50%, a pore size of 10 nm, a fiber length of 10 mm, and a fiber diameter of 500 μm; the catalytic component accounts for 20% of the total mass of the catalyst, and the catalytic component is a Pt-based material, in which Pt accounts for 10%, TiO2 accounts for 55%, and MnO2 accounts for 35%.

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

[0069] Example 3

[0070] A method for preparing a Pt-based coated catalyst, comprising the following steps:

[0071] Step 1: Same as Step 1 in Example 1;

[0072] Step 2: Immerse the coated substrate dried in Step 1 in an 8% phenol solution (ethanol as solvent) for 8 minutes. After immersion, remove it and rinse it with clean water for later use.

[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 and stir thoroughly. Add nitric acid to adjust the pH to 4.3 to obtain the catalytic component solution.

[0074] Step 4: Immerse the etched coating substrate obtained in Step 2 into the catalytic component solution prepared in Step 3. Stir and soak at 150 rpm for 10 min. Then, take out the coating substrate and immerse it in dilute ammonia water for 10 min, so that the catalytic component can form a catalytic gel on the coating substrate in an alkaline environment.

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

[0076] The Pt-based coated catalyst prepared in this embodiment is a fibrous felt with a thickness of 4 mm and a basis weight of 200 g / m². 2 It consists of a coating substrate and a catalytic component; the coating substrate is carbon fiber with a porosity of 50%, a pore size of 10 nm, a fiber length of 10 mm, and a fiber diameter of 500 μm; the catalytic component accounts for 20% of the total mass of the catalyst, and the catalytic component is a Pt-based material, in which Pt accounts for 15%, TiO2 accounts for 50%, and MnO2 accounts for 35%.

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

[0078] Comparative Example 1

[0079] The only difference from Example 2 is that the 8% phenol solution (solvent is ethanol) in step two is replaced with an 8% tetrachloroethane solution (solvent is ethanol); all other steps and parameters are the same as in Example 2.

[0080] The Pt-based coated catalyst prepared in this comparative example is a fibrous felt with a thickness of 4 mm and a basis weight of 200 g / m².2 It consists of a coating substrate and a catalytic component; the coating substrate is carbon fiber with a porosity of 50%, a pore size of 10 nm, a fiber length of 10 mm, and a fiber diameter of 500 μm; the catalytic component accounts for 20% of the total mass of the catalyst, and the catalytic component is a Pt-based material, in which Pt accounts for 12%, TiO2 accounts for 55%, MnO2 accounts for 33%, and the remaining component is the coating matrix (carbon fiber).

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

[0082] Comparative Example 2

[0083] The only difference from Example 2 is that the 8% phenol solution (solvent is ethanol) in step two is replaced with an 8% benzene solution (solvent is ethanol); all other steps and parameters are the same as in Example 2.

[0084] The Pt-based coated catalyst prepared in this comparative example is a fibrous felt with a thickness of 4 mm and a basis weight of 200 g / m². 2 It consists of a coating substrate and a catalytic component; the coating substrate is carbon fiber with a porosity of 50%, a pore size of 10 nm, a fiber length of 10 mm, and a fiber diameter of 500 μm; the catalytic component accounts for 20% of the total mass of the catalyst, and the catalytic component is a Pt-based material, in which Pt accounts for 10%, TiO2 accounts for 52%, and MnO2 accounts for 38%.

[0085] The Pt-based coated catalyst prepared in this comparative example has a maximum catalytic efficiency of 70% for formaldehyde and a maximum PM2.5 particulate matter interception efficiency of 70%.

[0086] Figure 1 An image showing the appearance of the Pt-based coated catalyst prepared in Example 2. Figure 1 It can be seen that the active components are uniformly dispersed on the surface of the support and there is no shedding, indicating that the prepared Pt-based coated catalyst has a high binding capacity for powder.

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

[0088] Figure 3 This is an electron microscope (EM) image of the catalyst before calcination in Example 2 (i.e., the coated substrate containing catalytic gel obtained in step four). Figure 3 It can be seen that after the active powder is loaded onto the carrier surface, a rough interface is formed, indicating that the active component has successfully combined with the carrier.

[0089] Figure 4 This is an electron microscope image of the calcined catalyst (i.e., the Pt-based coated catalyst) from Example 2. Figure 4 It can be seen that after calcination, the carrier and the active powder undergo interfacial bonding, and the active powder and the carrier are strongly bonded together, which can effectively prevent the active powder from falling off the surface of the carrier, thus proving that the prepared coated catalyst has high bonding strength.

[0090] Figure 5 The catalytic performance of the Pt-based coated catalyst prepared in Example 2 for formaldehyde is shown. Figure 5 It can be seen that under room temperature (20±5℃) conditions, it can achieve a purification efficiency of over 90% for 5-10ppm formaldehyde, thus achieving highly efficient purification of formaldehyde.

[0091] Figure 6 The PM2.5 filtration efficiency of the Pt-based coated catalyst prepared in Example 2 is shown. Figure 6 It can be seen that the average concentration of imported goods is 220 ug / m³. 3 The prepared Pt-based coated catalyst can achieve a particulate matter interception efficiency of more than 95% within 100 minutes, which is close to PM2.5.

[0092] 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. The application of a Pt-based coated catalyst in the removal of PM2.5 or VOCs gases, characterized in that, The preparation method of the Pt-based coated catalyst includes the following steps: The coated substrate is ultrasonically cleaned and then dried to obtain the dried coated substrate. The dried coating substrate is immersed in an etching solution for etching, and then cleaned to obtain the etched coating substrate. The etched coating substrate is sequentially immersed in a catalytic component solution and ammonia water to obtain a coating substrate containing catalytic gel; The coating substrate containing the catalytic gel is calcined to obtain the Pt-based coated catalyst; The catalytic component solution is prepared by adding chloroplatinic acid solution, tetrabutyl titanate solution and potassium permanganate solution to ethanol, mixing them, and adjusting the pH to 3-5. The Pt-based coated catalyst is in the form of a fibrous felt, composed of a coating substrate and catalytic components, with a thickness of 2-4 mm and a basis weight of 120-200 g / m³. 2 The coating substrate is carbon fiber with a porosity greater than 40%, a pore size of 0.5-10 nm, a fiber length of 3-10 mm, and a fiber diameter of 100-500 μm. The catalytic component accounts for 20%-40% of the total mass of the catalyst and is a Pt-based material. By mass percentage, the Pt-based material contains 10%-20% Pt, 50%-60% TiO2, and 30%-40% MnO2. The coating substrate is a wet-laid polyester nonwoven fabric; The etching solution is a phenol solution with a concentration of 2wt%-10wt%; The etching time is 8-30 minutes.

2. The application according to claim 1, characterized in that, The coated substrate is ultrasonically cleaned in a mixed solution of ethanol and water at a volume ratio of 3:8 for 30-50 minutes; the drying temperature is 50-80℃ and the time is 3-8 hours.

3. The application according to claim 1, characterized in that, The etched coated substrate was immersed in the catalytic component solution and ammonia water for 10-20 min and 5-10 min respectively.

4. The application according to claim 1, characterized in that, The calcination specifically involves calcining at 150-400℃ for 1-5 hours under a nitrogen atmosphere.

5. The application 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; and the volume ratio of the chloroplatinic acid solution, tetrabutyl titanate solution, potassium permanganate solution, and ethanol is 7:31:19:37.

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