A precious metal catalyst based on additive manufacturing and a method for its production

Abstract

The application relates to the technical field of catalysts, in particular to a precious metal catalyst based on additive manufacturing and a preparation method thereof. The preparation method of the precious metal catalyst based on additive manufacturing comprises the following steps: 1) uniformly mixing chloroplatinic acid hexahydrate, oleylamine and an organic solvent, stirring at 40-50 DEG C for 1-3 hours, then removing the organic solvent to obtain a compound; 2) uniformly mixing the compound prepared in the step 1) with 1,6-hexanediol diacrylate, trimethylolpropane triacrylate, a photoinitiator and a pore former, then adding alumina powder and a dispersant, ball milling, defoaming and preparing a slurry; 3) performing 3D printing on the slurry prepared in the step 2), and cleaning to obtain a green body; 4) first heat treating the green body obtained in the step 3) at 280-330 DEG C for 3-5 hours, then heat treating at 350-450 DEG C for 1-2 hours, then heat treating at 850-950 DEG C in a hydrogen-containing atmosphere for 2-4 hours, and cooling, thereby obtaining the catalyst. The catalyst prepared in the application can greatly reduce the peeling and loss of precious metals.

Description

Technical Field

[0001] This application relates to the field of catalyst technology, and more specifically, to a noble metal catalyst based on additive manufacturing and a method for its preparation. Background Technology

[0002] Volatile organic compounds (VOCs) are a class of organic compounds with boiling points between 50 and 250°C. They are a general term for carbon-containing organic compounds that are easily volatile at room temperature and mainly originate from industrial emissions, automobile exhaust, and building materials.

[0003] VOCs pose significant threats to human health and the environment: most VOCs are irritating, toxic, and even carcinogenic; long-term exposure may induce leukemia, nasopharyngeal carcinoma, and other diseases; short-term exposure can irritate the eyes, nose, and throat, causing headaches, nausea, and fatigue, and in severe cases, damage the nervous system. VOCs are key precursors to the formation of fine particulate matter (PM2.5) and near-surface ozone (O3). Under sunlight, VOCs can also react with nitrogen oxides to generate photochemical smog, exacerbating haze. VOCs have become a key factor restricting further improvement in air quality.

[0004] In the control of VOCs emissions from industrial sources, catalytic oxidation is one of the most promising methods. Catalytic oxidation can significantly reduce the oxidation temperature of VOCs, decrease the formation of byproducts, and lower energy consumption. Currently, most industrial VOCs oxidation catalysts employ monolithic catalytic materials supported by honeycomb supports. These typically use inert materials such as honeycomb ceramics as supports, coupled with rare earth or transition metal oxide coatings, and use noble metals such as Pt and Pd as the main active components.

[0005] In large-scale industrial catalytic applications such as catalytic combustion of volatile organic compounds (VOCs) and purification of automotive exhaust, catalysts must simultaneously meet stringent requirements of high throughput, low gas pressure drop, and extremely high mass transfer efficiency. Traditional granular or extruded honeycomb catalysts suffer from bottlenecks such as limited geometric shapes and mass transfer dead zones in the internal flow field. Additive manufacturing (3D printing) technology, however, has been introduced into the field of industrial catalysis in recent years due to its ability to freely construct complex topological macroscopic flow channels such as minimal surface matte (TPMS) or lattice crystals, demonstrating enormous potential to revolutionize fluid dynamics performance.

[0006] Currently, there are two main technical routes for additive manufacturing catalysts: blending printing and secondary coating. Blending printing involves directly mixing a metal precursor into an inorganic ceramic printing slurry for integrated molding and sintering. In industrial practice with continuous high-speed airflow, the metal utilization rate of blending printing is extremely low; with the same metal loading, its VOCs ignition temperature (T50) is often 40 to 60 degrees Celsius higher than that of conventional coating methods. Secondary coating involves first printing a pure inorganic ceramic framework and sintering it at high temperature, then coating the surface of the framework with a precious metal coating using an impregnation method.

[0007] Chinese invention patent application CN119500106A discloses a method for preparing manganese-based catalysts by 3D printing, which includes the following steps: (1) mixing photosensitive resin mixture with ceramic powder to obtain photosensitive ceramic slurry, and performing 3D printing to obtain a printed blank; (2) degreasing and sintering the printed blank to obtain a 3D printed ceramic carrier; (3) coating the surface of the 3D printed ceramic carrier with a slurry containing manganese oxide, and calcining to obtain a manganese-based catalyst.

[0008] While coating methods exhibit high initial activity, conversion rates often experience a sharp decline after prolonged continuous operation. The root cause of this failure lies in the lack of chemical bonding between the coating and the 3D-printed substrate, which has undergone photopolymerization and high-temperature densification. The coating is held together only by weak van der Waals forces, making it highly susceptible to large-scale peeling under the combined effects of shearing and scouring by high-speed industrial fluids and thermal stress caused by the difference in thermal expansion coefficients between the substrate and the coating. Therefore, there is an urgent need to develop a new additive manufacturing catalyst process to address the problem of surface coatings easily peeling off under fluid shear. Summary of the Invention

[0009] To reduce the exfoliation and loss of metal catalysts, this application provides a noble metal catalyst based on additive manufacturing and its preparation method.

[0010] Firstly, the method for preparing the noble metal catalyst based on additive manufacturing in this application adopts the following technical solution: A method for preparing a noble metal catalyst based on additive manufacturing includes the following steps: 1) Mix chloroplatinic acid hexahydrate, oleylamine, and organic solvent evenly, stir at 40-50℃ for 1-3 hours, and then remove the organic solvent to obtain the complex; 2) Mix the composite obtained in step 1) with 1,6-hexanediol diacrylate, trimethylolpropane triacrylate, photoinitiator, and pore-forming agent evenly, then add alumina powder and dispersant, ball mill, degas, and obtain slurry. 3) The slurry obtained in step 2) is 3D printed, cleaned, and a green body is obtained; 4) Hold the green body obtained in step 3) at 280-330℃ for 3-5 hours, then at 350-450℃ for 1-2 hours, and then at 850-950℃ for 2-4 hours in a hydrogen atmosphere. Cool it to obtain the final product.

[0011] The preparation method of this application first utilizes the polar end of oleylamine to complex with platinum ions, grafting hydrophobic long carbon chains onto it to facilitate subsequent enrichment at the interface. As a typical amphiphilic molecule, oleylamine's polar amino end can form stable coordination bonds with chloroplatinate ions, while its long-chain alkyl nonpolar end exhibits significant hydrophobicity. At the moment of polymerization-induced phase separation in the subsequent slurry, the system becomes a cross-linked resin phase containing inorganic powder and a liquid phase containing a pore-forming agent. The noble metal precursor encapsulated by oleylamine exhibits interfacial activity and accumulates in the space at the interface between the two phases. The synergistic effect of chemical coupling between components and phase separation mechanics guides the noble metal component to migrate towards the future pore surface. Subsequently, multi-stage heat treatment achieves multi-level pore solidification and semi-embedded reduction of the noble metal. The relatively low temperature of 280-330℃ converts organic matter into CO, CO2, and water vapor, leaving behind a microporous alumina framework and platinum compounds attached to the pore walls. A medium temperature of 350-450℃ can further promote the removal of residual organic matter and form finer micropores, while also preventing the agglomeration of platinum components caused by localized overheating. Then, at 850-950℃, in-situ reduction of platinum is promoted, maintaining a good dispersion state.

[0012] Preferably, the mass ratio of chloroplatinic acid hexahydrate to oleylamine in step 1) is 1-2:1.5-2.5.

[0013] Preferably, the organic solvent in step 1) is anhydrous ethanol. Preferably, in step 1), 50-200 mL of organic solvent is used for every 1-2 g of chloroplatinic acid hexahydrate.

[0014] Preferably, the stirring rate in step 1) is 500-700 rpm.

[0015] Preferably, the removal of organic solvent in step 1) is carried out by rotary evaporation. More preferably, the conditions for rotary evaporation are: vacuum degree of 10-50 Pa and water bath temperature of 45-50℃.

[0016] Preferably, in step 1), the chloroplatinic acid hexahydrate, oleylamine, and organic solvent are mixed evenly by first mixing the chloroplatinic acid hexahydrate with the organic solvent evenly, and then adding oleylamine dropwise under stirring. Preferably, the dropping rate is 0.5-2 mL / min.

[0017] Preferably, the mass ratio of chloroplatinic acid hexahydrate in step 1) to 1,6-hexanediol diacrylate in step 2) is 1-2:130-150.

[0018] Preferably, in step 2), the mass ratio of 1,6-hexanediol diacrylate to trimethylolpropane triacrylate is 130-150:40-50.

[0019] Preferably, in step 2), the mass ratio of 1,6-hexanediol diacrylate to porogen is 130-150:65-80.

[0020] Preferably, the porogen in step 2) is either polyethylene glycol or polytetrahydrofuran. More preferably, the porogen in step 2) is polyethylene glycol. More preferably, the porogen in step 2) is PEG-400.

[0021] The porogen selected in this application is a phase separation porogen, and in addition, amphiphilic ligands are used to pre-link the noble metal precursor, which enables the construction of a mesoporous network during the printing and curing process, and the use of interfacial tension to fix the noble metal to the pore walls.

[0022] Preferably, in step 2), the mass ratio of 1,6-hexanediol diacrylate to photoinitiator is 130-150:5-6.

[0023] Preferably, the photoinitiator in step 2) is diphenyl(2,4,6-trimethylbenzoyl)phosphine oxide (or diphenyl(2,4,6-trimethylbenzoyl)phosphine oxide).

[0024] Preferably, in step 2), the mass ratio of 1,6-hexanediol diacrylate to alumina is 130-150:200-500.

[0025] The amount of alumina used in this application should not be too high. Because alumina powder has a large specific surface area, it will lead to excessively high slurry viscosity, affecting the spreadability during printing, resulting in poor interlayer bonding and defects such as printing channel deformation and material shortage. However, if the amount of alumina used is too low, it will lead to a decrease in the mechanical strength of the carrier after sintering.

[0026] Preferably, the mass ratio of 1,6-hexanediol diacrylate to dispersant in step 2) is 130-150:8-15. Preferably, the dispersant in step 2) is a BYK dispersant. Preferably, the dispersant in step 2) is either BYK-180 or BYK-111.

[0027] The dispersant added in this application has acidic groups that can combine with the basic groups on the surface of alumina to achieve an anchoring function. Its long carbon chains extend within the resin, providing a certain steric hindrance effect. During ball milling, this is equivalent to coating the alumina with a hydrophobic coating, not only solving the problem of excessive viscosity but also ensuring that during phase separation, the alumina remains in the resin framework phase, repelling PEG and forming channels. Preferably, the dispersant is BYK-180. Its amine salt structure also has better compatibility with oleylamine, is less prone to severe side reactions, and is less likely to form excessive residues.

[0028] Step 2) involves mixing the composite obtained in step 1) with 1,6-hexanediol diacrylate, trimethylolpropane triacrylate, photoinitiator, and porogen. This includes stirring 1,6-hexanediol diacrylate, trimethylolpropane triacrylate, photoinitiator, and porogen until a mixture is obtained, then adding the composite obtained in step 1) and stirring until homogeneous.

[0029] Preferably, the ball milling speed in step 2) is 300-450 rpm. The ball milling time is 3-5 hours.

[0030] Preferably, the vacuum degree for degassing in step 2) is 0.03-0.05 MPa, and the degassing time is 20-40 min.

[0031] Preferably, a DLP 3D printer is used for 3D printing in step 3). Preferably, the ultraviolet light wavelength is 405nm. The single-layer exposure time is 2.5-6s. The layer thickness is 50-100μm. Anhydrous ethanol is used for cleaning, combined with ultrasonic treatment.

[0032] Preferably, in step 4), the heating rate during the holding period at 280-330℃ is 0.3-1℃ / min. The heating rate during the holding period at 350-450℃ is 1-1.5℃ / min. The heating rate during the holding period at 850-950℃ is 2-5℃ / min.

[0033] Because the slurry of this application contains a large amount of organic matter, the heating rate during the heat preservation at 280-330℃ is 0.3-1℃ / min. The slow heating can minimize the release of gas and greatly reduce the problems of bubbling and cracking.

[0034] Secondly, this application provides a noble metal catalyst based on additive manufacturing prepared by the above method.

[0035] In summary, this application has the following beneficial effects: This application utilizes the chemical coupling of polymerization-induced phase separation and amphiphilic ligand molecular assembly to anchor noble metals onto the inner wall surface of a mesoporous network, achieving a significant increase in active exposed surface area with the same noble metal loading. While maintaining the low pressure drop characteristics of the macroscopically complex flow channels in 3D printing, a three-dimensionally coherent transport channel is formed within the dense framework, maintaining high resistance to fluid shearing and high-temperature sintering, greatly reducing the exfoliation and loss of noble metals, and improving the theoretical service life of the material in real high-air-velocity industrial waste gas treatment scenarios. Detailed Implementation

[0036] The present application will be further described in detail below with reference to the embodiments.

[0037] Unless otherwise specified, the raw materials used in the embodiments and comparative examples of this application are all commercially available.

[0038] The alumina in the following embodiments is preferably a powder with a particle size of about 2 μm and a purity of 99.9%.

[0039] Example 1 The method for preparing the noble metal catalyst based on additive manufacturing in this embodiment includes the following steps: 1) Add 1.5g of chloroplatinic acid hexahydrate to 100mL of anhydrous ethanol and mix well. Then, under magnetic stirring (600rpm), add 2.0g of oleylamine dropwise and mix well. Keep the mixture at 40℃ and stir for 2h. After the reaction is complete, use a rotary evaporator to remove the anhydrous ethanol to obtain a dark brown viscous oleylamine-platinum complex. 2) In a light-protected environment, add 150g of 1,6-hexanediol diacrylate (HDDA), 45g of trimethylolpropane triacrylate (TMPTA), 80g of polyethylene glycol PEG-400, and 6g of diphenyl (2,4,6-trimethylbenzoyl)phosphoric acid (TPO) to a stirrer and stir at 800 rpm for 30 minutes to form a homogeneous mixture; Add all the complex obtained in step 1) to the mixture and continue stirring for 15 minutes; then add 450g of alumina powder and 15g of dispersant BYK-180 in three batches (each batch 10 minutes apart); after the addition is complete, transfer the mixture to a ball mill and use alumina balls (material-to-ball mass ratio of 1:2) to ball mill and mix at 350 rpm for 4 hours; after ball milling, place the slurry in a vacuum degassing machine and treat it under a negative pressure of 0.05 MPa for 30 minutes to obtain a grayish-white slurry; 3) Pour the slurry obtained in step 2) into the material tank of the 3D printer, import the pre-designed structural model (50mm×50mm×50mm, cross-sectional dimensions), and print at a wavelength of 405nm, a single-layer exposure time of 2.5s, and a light intensity of 18mW / cm². 2 Printing was performed with a layer thickness of 50μm; anhydrous ethanol was used in conjunction with ultrasonic cleaning to remove any remaining uncured slurry from the surface, resulting in a grayish-brown green body. 4) Place the green body obtained in step 3) in a tube furnace and perform programmed heating: first, heat to 300℃ at a rate of 1℃ / min and hold for 4h; then heat to 400℃ at a rate of 1℃ / min and hold for 2h; then introduce a mixed atmosphere of hydrogen and nitrogen in a volume ratio of 5:95 and heat to 900℃ at a rate of 2℃ / min and hold for 3h, then allow it to cool naturally to room temperature.

[0040] Example 2 The method for preparing the noble metal catalyst based on additive manufacturing in this embodiment includes the following steps: 1) Add 1.5g of chloroplatinic acid hexahydrate to 100mL of anhydrous ethanol and mix well. Then, under magnetic stirring (600rpm), add 1.8g of oleylamine dropwise and mix well. Keep the mixture at 40℃ and stir for 2h. After the reaction is complete, use a rotary evaporator to remove the anhydrous ethanol to obtain a dark brown viscous oleylamine-platinum complex. 2) In a light-protected environment, add 134.5g of 1,6-hexanediol diacrylate (HDDA), 50.5g of trimethylolpropane triacrylate (TMPTA), 72g of polyethylene glycol PEG-400, and 6g of diphenyl (2,4,6-trimethylbenzoyl)phosphoric acid (TPO) to a stirrer and stir at 800 rpm for 30 minutes to form a homogeneous mixture; Add all the complex obtained in step 1) to the mixture and continue stirring for 15 minutes; then add 420g of alumina powder and 15g of dispersant BYK-180 in three batches (each batch 10 minutes apart); after the addition is complete, transfer the mixture to a ball mill and use alumina balls (material-to-ball mass ratio of 1:2) to ball mill and mix at 350 rpm for 4 hours; after ball milling, place the slurry in a vacuum degassing machine and treat it under a negative pressure of 0.05 MPa for 30 minutes to obtain a grayish-white slurry; 3) Pour the slurry obtained in step 2) into the material tank of the 3D printer, import the pre-designed structural model (50mm×50mm×50mm, cross-sectional dimensions), and print at a wavelength of 405nm, a single-layer exposure time of 2.5s, and a light intensity of 18mW / cm². 2Printing was performed with a layer thickness of 50μm; anhydrous ethanol was used in conjunction with ultrasonic cleaning to remove any remaining uncured slurry from the surface, resulting in a grayish-brown green body. 4) Place the green body obtained in step 3) in a tube furnace and perform programmed heating: first, heat to 300℃ at a rate of 0.5℃ / min and hold for 4 hours; then heat to 400℃ at a rate of 1℃ / min and hold for 2 hours; then introduce a mixed atmosphere of hydrogen and nitrogen in a volume ratio of 5:95 and heat to 900℃ at a rate of 2℃ / min and hold for 3 hours, and then allow it to cool naturally to room temperature.

[0041] Example 3 The difference between this embodiment and embodiment 2 is that step 2) is: 2) In a light-protected environment, add 183g of 1,6-hexanediol diacrylate (HDDA), 50.5g of trimethylolpropane triacrylate (TMPTA), 120g of polyethylene glycol PEG-400, and 6g of diphenyl(2,4,6-trimethylbenzoyl)phosphoric acid (TPO) to a stirrer and stir at 800 rpm for 30 minutes to form a homogeneous mixture; Add all the complex obtained in step 1) to the mixture and continue stirring for 15 minutes; then add 420g of alumina powder and 15g of dispersant BYK-180 in three batches (each batch 10 minutes apart); after the addition is complete, transfer the mixture to a ball mill and use alumina balls (material-to-ball mass ratio of 1:2) to ball mill and mix at 350 rpm for 4 hours; after ball milling, place the slurry in a vacuum degassing machine and treat it under a negative pressure of 0.05 MPa for 30 minutes to obtain a grayish-white slurry.

[0042] Everything else is the same as in Example 2.

[0043] Example 4 The difference between this embodiment and embodiment 2 is that step 4) is: 4) Place the green body obtained in step 3) in a tube furnace and perform programmed heating: first, heat to 300℃ at a rate of 0.5℃ / min and hold for 4 hours; then heat to 400℃ at a rate of 1℃ / min and hold for 2 hours; then introduce a mixed atmosphere of hydrogen and nitrogen in a volume ratio of 5:95 and heat to 1200℃ at a rate of 2℃ / min and hold for 3 hours; then cool naturally to room temperature.

[0044] Everything else is the same as in Example 2.

[0045] Example 5 The difference between this embodiment and embodiment 2 is that step 3) is: 3) Pour the slurry obtained in step 2) into the material tank of the 3D printer, import the pre-designed structural model (50mm×50mm×50mm, cross-sectional dimensions), and print at a wavelength of 405nm, a single-layer exposure time of 6.0s, and a light intensity of 18mW / cm². 2 Printing was performed with a layer thickness of 50μm; anhydrous ethanol was used in conjunction with ultrasonic cleaning to remove any remaining uncured slurry from the surface, resulting in a grayish-brown green body. Everything else is the same as in Example 2.

[0046] Comparative Example 1 The difference between this comparative example and Example 2 is that: 1) Add 1.5g of chloroplatinic acid hexahydrate to 100mL of water, mix well, and then stir magnetically at 40℃ (600rpm) for 2h; 2) In a light-protected environment, add 134.5g of 1,6-hexanediol diacrylate (HDDA), 50.5g of trimethylolpropane triacrylate (TMPTA), 72g of polyethylene glycol PEG-400, and 6g of diphenyl (2,4,6-trimethylbenzoyl)phosphoric acid (TPO) to a stirrer and stir at 800 rpm for 30 minutes to form a homogeneous mixture; Add all the mixture from step 1) to the mixture and continue stirring for 15 minutes; then add 420g of alumina powder and 15g of dispersant BYK-180 in three batches (each batch 10 minutes apart); after the addition is complete, transfer the mixture to a ball mill and use alumina balls (material-to-ball mass ratio of 1:2) to ball mill and mix at 350 rpm for 4 hours; after ball milling, place the slurry in a vacuum degassing machine and treat it under a negative pressure of 0.05 MPa for 30 minutes to obtain the slurry.

[0047] Everything else is the same as in Example 2.

[0048] Comparative Example 2 The difference between this comparative example and Example 2 is that: 1) Add 1.5g of chloroplatinic acid hexahydrate to 100mL of anhydrous ethanol and mix well. Then, under magnetic stirring (600rpm), add 1.8g of oleylamine dropwise and mix well. Keep the mixture at 40℃ and stir for 2h. After the reaction is complete, use a rotary evaporator to remove the anhydrous ethanol to obtain a dark brown viscous oleylamine-platinum complex. 2) In a light-protected environment, add 206.5g of 1,6-hexanediol diacrylate (HDDA), 50.5g of trimethylolpropane triacrylate (TMPTA), and 6g of diphenyl(2,4,6-trimethylbenzoyl)phosphoric acid (TPO) to a stirrer and stir at 800 rpm for 30 minutes to form a homogeneous mixture. Add all the complex obtained in step 1) to the mixture and continue stirring for 15 minutes; then add 420g of alumina powder and 15g of dispersant BYK-180 in three batches (each batch 10 minutes apart); after the addition is complete, transfer the mixture to a ball mill and use alumina balls (material-to-ball mass ratio of 1:2) to ball mill and mix at 350 rpm for 4 hours; after ball milling, place the slurry in a vacuum degassing machine and treat it under a negative pressure of 0.05 MPa for 30 minutes to obtain a grayish-white slurry.

[0049] Everything else is the same as in Example 2.

[0050] Experimental Example (1) Physicochemical tests The catalysts prepared in Examples 1-5 and Comparative Examples 1-2 were subjected to physicochemical property tests, and the test results are shown in the table below.

[0051] Table 1. Physicochemical test data of Examples 1-5 and Comparative Examples 1-2

[0052] The catalysts prepared in Examples 1 and 2 have a moderate specific surface area (55-58 m² / g) and a large average pore size (170-185 nm), and the platinum particles are uniformly dispersed and small in size. This provides sufficient channels and active sites for mass transfer and catalytic reaction, thereby achieving excellent catalytic activity and good structural stability.

[0053] Although the average pore size increased in Example 3, the specific surface area decreased due to the excessively large pore size, and the dispersibility of the platinum particles was not affected. The catalytic activity was similar to that in Example 2.

[0054] Example 4: Due to excessively high calcination temperature, the pore structure collapsed, the specific surface area decreased, and the platinum particles severely agglomerated, resulting in a significant reduction in catalytic activity.

[0055] Example 5: Due to excessive exposure time in a single layer, some platinum particles were encapsulated in the framework, resulting in a reduction in average pore size and effective active sites, which in turn reduced catalytic activity.

[0056] In Comparative Example 1, since no oleylamine was added, the platinum particles were encapsulated in the framework and could not fully expose the active sites, resulting in reduced catalytic activity.

[0057] In Comparative Example 2, since no pore-forming agent was added, the final catalyst formed was a dense ceramic framework with no mass transfer channels and most of the platinum particles were encapsulated in the framework, resulting in extremely low catalytic activity.

[0058] (2) Catalytic performance test The catalysts prepared in Examples 1-5 and Comparative Examples 1-2 were subjected to catalytic performance tests, and the test results are shown in the table below.

[0059] Table 2. Performance test results of catalysts prepared in Examples 1-5 and Comparative Examples 1-2

[0060] Examples 1 and 2, through optimization of the reactant monomer and pore-forming agent dosages, yielded excellent catalytic activity (T90 < 200℃), good mechanical strength (compressive strength > 45 MPa), and excellent structural stability (ultrasonic shedding rate < 0.2%, structural integrity after simulated exhaust gas impact test). This fully demonstrates that the additive manufacturing-based noble metal catalyst preparation method provided in this application achieves a good balance between catalytic activity, mechanical strength, and structural stability.

[0061] The test results of Examples 2 and 3 show that although excessive use of porogen PEG-400 can maintain good catalytic activity, it will lead to a significant reduction in the mechanical strength of the final catalyst, making it unable to withstand gas impacts in actual industrial applications.

[0062] The test results of Examples 2 and 4 show that excessively high calcination temperature can lead to a severe reduction in the catalytic activity of the catalyst. This is because high temperature causes the catalyst pore structure to collapse and the active component platinum particles to agglomerate.

[0063] The test results of Examples 2 and 5 show that while appropriately extending the exposure time of a single layer in 3D printing can improve the mechanical strength of the catalyst, it can reduce its catalytic activity. This may be because rapid curing causes some platinum particles to be encapsulated inside the matrix and unable to effectively contact the reactants.

[0064] As can be seen from the test results of Example 2, Comparative Examples 1 and 2, the catalytic activity of the final catalysts was significantly reduced after removing oleylamine or PEG-400.

[0065] This specific embodiment is merely an explanation of this application and is not intended to limit it. After reading this specification, those skilled in the art can make modifications to this embodiment without contributing any inventive step, but such modifications are protected by patent law as long as they fall within the scope of the claims of this application.

Claims

1. A method for preparing a noble metal catalyst based on additive manufacturing, characterized in that, Includes the following steps: 1) Mix chloroplatinic acid hexahydrate, oleylamine, and organic solvent evenly, stir at 40-50℃ for 1-3 hours, and then remove the organic solvent to obtain the complex; 2) Mix the composite obtained in step 1) with 1,6-hexanediol diacrylate, trimethylolpropane triacrylate, photoinitiator, and pore-forming agent evenly, then add alumina powder and dispersant, ball mill, degas, and obtain slurry. 3) The slurry obtained in step 2) is 3D printed, cleaned, and a green body is obtained; 4) Hold the green body obtained in step 3) at 280-330℃ for 3-5 hours, then at 350-450℃ for 1-2 hours, and then at 850-950℃ for 2-4 hours in a hydrogen atmosphere. Cool it to obtain the final product.

2. The method for preparing a noble metal catalyst based on additive manufacturing according to claim 1, characterized in that, In step 1), the mass ratio of chloroplatinic acid hexahydrate to oleylamine is 1-2:1.5-2.

5.

3. The method for preparing a noble metal catalyst based on additive manufacturing according to claim 1, characterized in that, In step 1), the chloroplatinic acid hexahydrate, oleylamine, and organic solvent are mixed evenly by first mixing the chloroplatinic acid hexahydrate with the organic solvent evenly, and then adding oleylamine dropwise under stirring conditions.

4. The method for preparing a noble metal catalyst based on additive manufacturing according to claim 1, characterized in that, The mass ratio of chloroplatinic acid hexahydrate in step 1) to 1,6-hexanediol diacrylate in step 2) is 1-2:130-150.

5. The method for preparing a noble metal catalyst based on additive manufacturing according to claim 4, characterized in that, In step 2), the mass ratio of 1,6-hexanediol diacrylate to trimethylolpropane triacrylate is 130-150:40-50.

6. The method for preparing a noble metal catalyst based on additive manufacturing according to claim 4, characterized in that, In step 2), the mass ratio of 1,6-hexanediol diacrylate to porogen is 130-150:65-80.

7. The method for preparing a noble metal catalyst based on additive manufacturing according to claim 1, characterized in that, In step 2), the porogen is either polyethylene glycol or polytetrahydrofuran.

8. The method for preparing a noble metal catalyst based on additive manufacturing according to claim 1, characterized in that, In step 2), the mass ratio of 1,6-hexanediol diacrylate to alumina is 130-150:200-500.

9. The method for preparing a noble metal catalyst based on additive manufacturing according to any one of claims 1-8, characterized in that, In step 4), the heating rate is 0.3-1℃ / min when holding at 280-330℃; the heating rate is 1-1.5℃ / min when holding at 350-450℃; and the heating rate is 2-5℃ / min when holding at 850-950℃.

10. A noble metal catalyst based on additive manufacturing prepared by the method of claim 1.

Images