In-vehicle purification material as well as preparation method and application thereof

Abstract

The invention discloses an in-vehicle purification material and a preparation method and application thereof, and relates to the technical field of in-vehicle air purification, the purification material provided by the invention is a perovskite type metal oxide catalyst with a three-dimensional ordered macroporous structure, has excellent catalytic activity and poisoning resistance, and is suitable for in-vehicle air purification.

Description

Technical Field

[0001] This application relates to the field of in-vehicle air purification technology, and in particular to an in-vehicle purification material, its preparation method, and its application. Background Technology

[0002] In recent years, with consumers paying significantly more attention to in-vehicle air quality, it has become a key consideration in their car-buying decisions. Continued media coverage of in-vehicle air pollution has sparked widespread public attention and in-depth discussions. To protect consumer rights, relevant government departments have gradually strengthened their oversight of in-vehicle air quality, issuing a series of standards and regulations, such as the "GB / T 27630 Guidelines for Evaluating Air Quality in Passenger Cars," which clearly stipulates the concentration limits for harmful substances in in-vehicle air. These measures have prompted automakers to increase their investment in research and development of in-vehicle air purification technologies, driving continuous innovation and development in this field.

[0003] Currently, in-vehicle air purification technologies mainly include activated carbon adsorption technology, negative ion generator technology, plasma purification technology, photocatalytic technology, and catalytic oxidation technology. Catalytic oxidation utilizes a catalyst to enable volatile organic compounds to undergo flameless combustion at a relatively low ignition temperature, decomposing them into carbon dioxide and water vapor. It has advantages such as low energy consumption, wide applicability, and no secondary pollution.

[0004] However, existing catalytic purification technologies still have significant shortcomings. For example, traditional heating catalysis relies on gas heat transfer, which suffers from low heat transfer efficiency, uneven temperature inside the catalyst, and slow start-up response; while some perovskite catalyst preparation methods can easily lead to the encapsulation of active sites, affecting catalytic efficiency.

[0005] Therefore, developing in-vehicle purification materials that combine high catalytic activity and anti-poisoning properties has become an urgent problem to be solved in the industry. Summary of the Invention

[0006] This application provides an in-vehicle purification material (which may be simply referred to as a purification material) and its preparation method and application. The purification material provided in this application is a perovskite-type metal oxide catalyst with a three-dimensional ordered macroporous structure, which has excellent catalytic activity and anti-poisoning performance.

[0007] In a first aspect, this application provides an in-vehicle purification material, which includes a perovskite-type metal oxide having a three-dimensional ordered macroporous structure.

[0008] The purification material provided in this application is a perovskite-type metal oxide. The perovskite-type metal oxide has a three-dimensional ordered macroporous structure with a high specific surface area, pore volume, and ordered channels, which is conducive to the diffusion of reactant gases and improves the reaction rate. The active components are uniformly dispersed on the surface of the channels in the form of nanoparticles, avoiding the aggregation problem of traditional methods and exposing more active sites, thereby improving the catalytic activity and anti-poisoning performance of the purification material and achieving efficient purification of various VOCs in the vehicle.

[0009] In some embodiments, the chemical formula of the perovskite-type metal oxide is La. 1-x M x Mn y Fe 1-y O3, where M includes one of Ca, Ba, and Sm, X = 0.01~0.3, and y = 0.1~0.9. Perovskite-type metal oxides have a specific chemical composition La. 1-x M x Mn y Fe 1-y O3 (M is one of Ca, Ba, and Sm, x=0.01~0.3, y=0.1~0.9) This composition, combined with a three-dimensional ordered macroporous structure, effectively regulates the crystal structure and surface chemical properties through the synergistic effect of A-site doping and B-site Mn-Fe, significantly increasing the oxygen vacancy concentration and enhancing the reactivity of surface oxygen species. At the same time, this specific composition range is conducive to the uniform dispersion and stable existence of active sites on the pore surface, thereby synergistically achieving high catalytic activity, excellent resistance to poisoning, and structural stability, realizing efficient and deep oxidation purification of various VOCs in the vehicle.

[0010] In some embodiments, the pore size of the perovskite metal oxide is 100-300 nm. Limiting the pore size of the perovskite metal oxide to this range ensures that the vast majority of gas molecules can freely enter and exit, avoiding blockage. Furthermore, it can shorten the diffusion path, reduce mass transfer resistance, and increase the overall reaction rate.

[0011] In some embodiments, the pore volume of the perovskite-type metal oxide is 0.1~2 cm³. 3 / g. Limiting the pore volume of perovskite-type metal oxides to the above range provides ample internal space for loading other active components; in addition, it can protect sensitive catalytic species from deactivation in harsh environments.

[0012] In some embodiments, the specific surface area of ​​the perovskite-type metal oxide is 30-100 m². 2 / g. By limiting the specific surface area of ​​perovskite-type metal oxides to the above range, they possess a high density of surface active sites, exhibiting excellent catalytic activity.

[0013] Secondly, this application provides a method for preparing the aforementioned in-vehicle air purification material, comprising: A mixed salt solution is obtained by mixing La salt, M salt, Mn salt, Fe salt and solvent, wherein M includes one of Ca, Ba and Sm. The polymethyl methacrylate microsphere template was impregnated in the mixed salt solution, and after standing and filtration, it was dried to obtain the impregnation intermediate. The impregnated intermediate is calcined to obtain an in-vehicle purification material.

[0014] The preparation method provided in this application successfully constructs a perovskite-type metal oxide with a three-dimensional ordered macroporous structure by impregnating a polymethyl methacrylate (PMMA) microsphere template with a mixed salt solution of a specific chemical composition, followed by a calcination process. This method enables uniform dispersion of the active components within the material, effectively preventing particle agglomeration, significantly increasing the specific surface area and pore volume, thereby fully exposing catalytic active sites and enhancing the mass transfer efficiency of reactant gases. The preparation process is stable and controllable, and the resulting purification material exhibits high catalytic activity, excellent thermal stability, and anti-poisoning properties in in-vehicle VOCs purification.

[0015] In some embodiments, the solvent includes a mixture of methanol and ethylene glycol. Using the above-mentioned solvent allows for synergistic dissolution, leveraging both the strong dissolving and complexing capabilities of ethylene glycol and the viscosity-reducing effect of methanol, thus achieving effective dissolution and uniform mixing of the precursor.

[0016] In some embodiments, the volume ratio of methanol to ethylene glycol is 1:(3~5). Limiting the volume ratio of methanol to ethylene glycol within this range significantly reduces the risk of dissolution of the PMMA template. Ethylene glycol, as the main component of the mixed solvent, alters the overall solubility and moves it away from the PMMA dissolution zone. Furthermore, at this ratio, the complexing effect of ethylene glycol combined with the diluting effect of methanol effectively controls the condensation reaction rate of metal ions, which is beneficial for forming a final catalytic material with smaller crystallite size and higher specific surface area.

[0017] In some embodiments, the mixing treatment temperature is 30–50°C. Limiting the mixing treatment temperature within this range improves solubility and dissolution efficiency, as higher temperatures enhance molecular thermal motion and increase solvent diffusion. Excessively high temperatures may cause precursor decomposition and template damage. The 30–50°C temperature range effectively promotes dissolution and complexation while remaining well below the solvent's boiling point and the nitrate's decomposition temperature, ensuring operational safety and material stability.

[0018] In some embodiments, the settling process is performed under vacuum for 12–24 hours. This settling period within this range completely eliminates air from the template pores. Since the PMMA template is a three-dimensional network formed by tightly packed microspheres, it contains a large amount of air. These air bubbles can become significant obstacles to the permeation of the precursor solution, leading to incomplete filling and potentially resulting in pore defects. Additionally, it helps degas the mixed solvent. The solution itself may dissolve trace amounts of gas, which may precipitate and form bubbles during subsequent processing. Vacuum settling removes these gases, further improving the homogeneity and permeability of the solution.

[0019] In some embodiments, the drying temperature is 50–70°C. Drying within this temperature range allows for the smooth removal of the low-boiling-point solvent (methanol) without structural damage; it also maintains the supporting role of the high-boiling-point solvent (ethylene glycol), supporting the skeletal structure. Methanol has a boiling point of 65°C; setting the drying temperature within this range precisely covers methanol's boiling point, ensuring that methanol is effectively converted to a gaseous state and removed. Ethylene glycol, with a boiling point as high as 197°C, has a very low evaporation rate within this temperature range. It supports the initial gel network formed by the precursor, preventing it from collapsing due to the large capillary forces after methanol evaporation.

[0020] In some embodiments, the drying process takes 24–36 hours. This time range ensures a low evaporation rate, minimizing capillary stress. During the drying of porous gels, the greatest destructive force comes from the capillary stress generated during liquid evaporation. Sufficient drying time allows the solvent evaporation front to advance slowly, giving the gel skeleton enough time to elastically deform and rearrange, thereby safely releasing internal stress and effectively preventing cracking and collapse. Furthermore, it allows for deep solvent removal. If drying is incomplete, residual solvent will decompose or carbonize violently during subsequent high-temperature calcination, not only generating significant destructive force but also potentially introducing carbon impurities and contaminating the catalyst.

[0021] In some embodiments, the calcination includes a first calcination and a second calcination. By employing a two-stage calcination process, the complete and stable removal of organic components can be achieved. The first calcination specifically targets the decomposition and oxidation of all organic matter (PMMA template, ethylene glycol solvent, and possible complexes). The second calcination focuses on the crystallization of the inorganic catalyst framework. Furthermore, crystal growth and phase transitions can be precisely controlled. The catalyst activity is closely related to its crystal phase; the second high-temperature calcination allows for independent optimization of temperature and time to generate the target crystal phase and control grain size, avoiding over-sintering, thereby achieving high specific surface area and high catalytic activity.

[0022] In some embodiments, the first calcination is programmed to increase the temperature at a rate of 1-2°C / min to 250-300°C and calcinate for 2-4 hours. This limited first calcination process ensures safe and thorough removal of organic matter without damaging the framework structure. Slow heating ensures that the decomposition and oxidation of PMMA and ethylene glycol are gradual and controllable. The target temperature range is above the solvent boiling point but below the framework sintering temperature, ensuring complete solvent removal. Sufficient calcination time guarantees deep and complete removal of the template.

[0023] In some embodiments, the second calcination is programmed to be performed at a heating rate of 1-2°C / min, reaching 600-800°C for 4-6 hours. This limited second calcination process allows the amorphous framework to be transformed into a high-performance catalyst with the target crystalline phase, high specific surface area, and excellent stability while maintaining the macroporous structure. The heating rate (1-2°C / min) allows for a smooth transition to high temperatures, minimizing stress during crystallization. The phase transition from amorphous to crystalline is accompanied by volume changes. Slow heating allows the phase transition to occur more uniformly throughout the sample, avoiding internal stress caused by rapid local crystallization. Calcination at 600-800°C ensures sufficient crystallization of the catalyst framework; this temperature range is typical for most metal oxides to form stable target crystalline phases. Furthermore, over-sintering can be avoided. If the temperature is too low, crystallization will be incomplete and the catalytic activity will be low; if the temperature is too high (e.g., >900°C), the grains will grow rapidly and sinter, causing the walls of the macroporous framework to become denser, the pore size to shrink, and the specific surface area to drop sharply, thereby reducing the catalytic performance.

[0024] In some embodiments, the preparation method of the polymethyl methacrylate microsphere template includes: mixing methyl methacrylate with deionized water, heating to 80-90°C under stirring, adding potassium persulfate aqueous solution, continuing the reaction for 2-3 hours, and then filtering, centrifuging, washing and drying to obtain the polymethyl methacrylate microsphere template.

[0025] This preparation process utilizes an aqueous environment of 80–90°C and potassium persulfate initiation to polymerize methyl methacrylate (PMMA), effectively controlling the sphericity and particle size distribution of PMMA microspheres. Following filtration, centrifugation, and drying, a PMMA microsphere template with a well-defined structure and good monodispersity is obtained. This preparation process is stable and highly reproducible, providing a uniform and size-controllable template foundation for the subsequent construction of perovskite catalysts with a three-dimensional ordered macroporous structure. This ensures that the final purification material possesses a regular pore structure and excellent mass transfer performance.

[0026] Thirdly, this application provides an application of the aforementioned in-vehicle purification material, characterized in that the in-vehicle purification material is used for in-vehicle air purification.

[0027] This application applies the purification material to in-vehicle air purification, which can fully utilize its three-dimensional ordered macroporous structure and high catalytic activity to efficiently degrade various volatile organic compounds (VOCs) such as benzene, toluene, formaldehyde, and acetaldehyde in the vehicle air conditioning system or air purification device, converting them into harmless carbon dioxide and water at a lower ignition temperature, thereby significantly improving the air quality inside the vehicle, meeting the relevant national standards, and possessing the advantages of long-lasting purification with resistance to poisoning and good stability. Detailed Implementation

[0028] To enable those skilled in the art to better understand the present application, the technical solutions in the embodiments of the present application are clearly and completely described. Obviously, the described embodiments are only some embodiments of the present application, and not all embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present application.

[0029] In recent years, with consumers paying significantly more attention to in-vehicle air quality, it has become a key factor in the car-buying decision-making process. Continued media coverage of in-vehicle air pollution has sparked widespread public concern and in-depth discussions. To protect consumer rights, relevant government departments have gradually strengthened their supervision of in-vehicle air quality, issuing a series of standards and regulations, such as the "GB / T 27630 Guidelines for Evaluating Air Quality in Passenger Cars," which clearly stipulates the concentration limits of harmful substances in in-vehicle air. These measures have prompted automakers to increase their investment in the research and development of in-vehicle air purification technologies, driving continuous innovation and development in this field.

[0030] Currently, common in-vehicle air purification technologies include activated carbon adsorption, negative ion generators, plasma purification, photocatalysis, and catalytic oxidation. Among these, catalytic oxidation, which uses a catalyst to cause volatile organic compounds to undergo flameless combustion at a relatively low ignition temperature, decomposing them into carbon dioxide and water, has advantages such as low energy consumption, wide applicability, and no secondary pollution, and is considered a promising purification method.

[0031] Catalysts used in catalytic oxidation methods are mainly classified into two categories: noble metals (such as platinum and palladium) and transition metal oxides (such as manganese, cobalt, and copper). Noble metal catalysts exhibit outstanding performance, stability, and resistance to high temperatures, acids, alkalis, and humidity, but they are expensive. Transition metal oxide catalysts, while less expensive, have relatively weaker catalytic performance, are prone to deactivation and poisoning, and only show high catalytic efficiency for specific pollutants. Furthermore, since VOC concentrations are generally low in vehicles, it is not conducive to the catalyst fully exerting its catalytic oxidation effect. Three-dimensional porous materials can be used to adsorb and enrich VOC molecules using their large specific surface area and numerous holes, increasing their local reaction concentration and thus improving catalytic oxidation efficiency. Perovskite catalysts, due to their controllable oxygen vacancies, good thermal stability, and resistance to poisoning, have attracted increasing attention from researchers in recent years.

[0032] In the prior art, Chinese patent CN207088916U discloses an air purification system, including a detection device, a catalytic module, and a heating module. By detecting the VOC concentration, the controller activates the purification device, causing the air to pass through the catalytic and heating modules for decomposition, purification, and then return to the vehicle. Simultaneously, an adsorption module can be used for further purification. However, the specific structure and active component distribution of the catalytic module in this system are not disclosed in detail, and the heating method relies on gas heat transfer, resulting in problems such as low heat transfer efficiency, uneven internal temperature of the catalyst, and slow start-up response.

[0033] Another Chinese patent, CN106475105A, discloses a double perovskite composite metal oxide catalyst, its preparation method, and its application. Its chemical formula is A2B2O6, where the A-site is La, Sr, or Ce, and the B-site is Mn, Fe, Co, Cu, or Ni. The catalyst surface is also loaded with transition metal oxides, with the loading amount being 5-20% of the total mass of the catalyst and the loaded oxides. This catalyst is prepared using the citric acid method, but this method easily leads to the active sites being encapsulated by catalyst particles, affecting catalytic efficiency.

[0034] In summary, existing in-vehicle purification materials still have shortcomings in terms of structural design, exposure of active sites, and mass transfer efficiency. Developing new purification materials that combine high catalytic activity, excellent anti-poisoning properties, and suitability for low-temperature start-up environments in vehicles has become an urgent technical problem to be solved in this field.

[0035] In view of this, this application provides an in-vehicle purification material, its preparation method and application. The purification material provided by this application is a perovskite-type metal oxide catalyst with a three-dimensional ordered macroporous structure, which has excellent catalytic activity and anti-poisoning performance.

[0036] In a first aspect, this application provides an in-vehicle purification material. According to an embodiment of this application, the in-vehicle purification material includes a perovskite-type metal oxide, which has a three-dimensional ordered macroporous structure.

[0037] The purification material provided in this application has a three-dimensional ordered macroporous structure, with a high specific surface area, pore volume and ordered channels, which is conducive to the diffusion of reactant gases and improves the reaction rate. The active components are uniformly dispersed on the surface of the channels in the form of nanoparticles, avoiding the agglomeration problem of traditional methods, exposing more active sites, thereby improving the catalytic activity and anti-poisoning performance of the purification material, and achieving efficient purification of various VOCs in the vehicle.

[0038] In conjunction with the first aspect, the chemical formula of the perovskite-type metal oxide is La. 1-x M x Mn y Fe 1-y O3, wherein M includes one of Ca, Ba, and Sm, X = 0.01~0.3, and y = 0.1~0.9.

[0039] The perovskite-type metal oxide provided in this application has a specific chemical composition La. 1-x M x Mn y Fe 1-y O3 (M is one of Ca, Ba, and Sm, x=0.01~0.3, y=0.1~0.9) This composition, combined with a three-dimensional ordered macroporous structure, effectively regulates the crystal structure and surface chemical properties through the synergistic effect of A-site doping and B-site Mn-Fe, significantly increasing the oxygen vacancy concentration and enhancing the reactivity of surface oxygen species. At the same time, this specific composition range is conducive to the uniform dispersion and stable existence of active sites on the pore surface, thereby synergistically achieving high catalytic activity, excellent resistance to poisoning, and structural stability, realizing efficient and deep oxidation purification of various VOCs in the vehicle.

[0040] In conjunction with the first aspect, in some embodiments provided in this application, the pore size of the perovskite metal oxide is 100-300 nm. Limiting the pore size of the perovskite metal oxide to this range ensures that the vast majority of gas molecules can freely enter and exit, avoiding blockage. Furthermore, it can shorten the diffusion path, reduce mass transfer resistance, and improve the overall reaction rate.

[0041] In conjunction with the first aspect, in some embodiments provided in this application, the pore volume of the perovskite-type metal oxide is 0.1~2 cm³. 3 / g. Limiting the pore volume of perovskite-type metal oxides to the above range provides ample internal space for loading other active components; in addition, it can protect sensitive catalytic species from deactivation in harsh environments.

[0042] In conjunction with the first aspect, in some embodiments provided in this application, the specific surface area of ​​the perovskite-type metal oxide is 30~100 m². 2 / g. By limiting the specific surface area of ​​perovskite-type metal oxides to the above range, they possess a high density of surface active sites, exhibiting excellent catalytic activity.

[0043] Secondly, this application provides a method for preparing the above-mentioned in-vehicle purification material. According to an embodiment of this application, La salt, M salt, Mn salt, Fe salt and solvent are mixed to obtain a mixed salt solution, wherein M includes one of Ca, Ba and Sm; polymethyl methacrylate microsphere templates are impregnated in the mixed salt solution, and after standing and filtration, they are dried to obtain an intermediate; the intermediate is calcined to obtain the purification material.

[0044] The preparation method provided in this application successfully constructs a perovskite-type metal oxide with a three-dimensional ordered macroporous structure by impregnating a polymethyl methacrylate (PMMA) microsphere template with a mixed salt solution of a specific chemical composition, followed by a calcination process. This method enables uniform dispersion of the active components within the material, effectively preventing particle agglomeration, significantly increasing the specific surface area and pore volume, thereby fully exposing catalytic active sites and enhancing the mass transfer efficiency of reactant gases. The preparation process is stable and controllable, and the resulting purification material exhibits high catalytic activity, excellent thermal stability, and anti-poisoning properties in in-vehicle VOCs purification.

[0045] According to an embodiment of the present invention, the method includes: S100, Preparation of mixed salt solution In this step, La salt, M salt, Mn salt, Fe salt and solvent are mixed, wherein M includes one of Ca, Ba and Sm, to obtain a mixed salt solution.

[0046] It should be noted that this application does not strictly limit the specific types of soluble metal salts such as La, M, Mn, and Fe salts. Those skilled in the art can flexibly select them based on actual process conditions, cost, and availability. For example, the salts can be water-soluble or alcohol-soluble compounds such as nitrates, acetates, and chlorides.

[0047] To better illustrate and implement this solution, nitrates are consistently used as examples in the specific embodiments of this application: La salt is lanthanum nitrate, M salt is the nitrate corresponding to metal M (Ca, Ba, Sm) (such as calcium nitrate, barium nitrate, samarium nitrate), Mn salt is manganese nitrate, and Fe salt is iron nitrate.

[0048] In conjunction with the second aspect, in some embodiments provided in this application, the solvent includes a mixture of methanol and ethylene glycol. Using the aforementioned solvent allows for synergistic dissolution, leveraging both the strong dissolving and complexing capabilities of ethylene glycol and the viscosity-reducing effect of methanol, thus achieving effective dissolution and uniform mixing of the precursor.

[0049] In conjunction with the second aspect, in some embodiments provided in this application, the volume ratio of methanol to ethylene glycol is 1:(3~5). Limiting the volume ratio of methanol to ethylene glycol to this range can significantly reduce the risk of dissolution of the PMMA template. Ethylene glycol, as the main component of the mixed solvent, alters the overall solubility and moves it away from the PMMA dissolution zone. Furthermore, at this ratio, the complexing effect of ethylene glycol combined with the diluting effect of methanol can effectively control the condensation reaction rate of metal ions, which is beneficial for forming a final catalytic material with smaller crystal size and higher specific surface area.

[0050] In conjunction with the second aspect, in some embodiments provided in this application, the mixing treatment temperature is 30~50°C. Limiting the mixing treatment temperature within this range can improve solubility and dissolution efficiency, as increased temperature enhances molecular thermal motion and improves the solvent's diffusion capacity. Excessively high temperatures may cause precursor decomposition and template damage. A temperature range of 30~50°C effectively promotes dissolution and complexation while remaining well below the boiling point of the solvent and the decomposition temperature of nitrates, ensuring operational safety and material stability.

[0051] S200, Perform template impregnation treatment In this step, the polymethyl methacrylate microsphere template is impregnated in the mixed salt solution obtained in step S100, and after standing and filtration, it is dried to obtain the impregnation intermediate.

[0052] In conjunction with the second aspect, in some embodiments provided in this application, the settling is performed under vacuum for 12-24 hours. This settling process within the aforementioned range can completely eliminate air from the template pores. Since the PMMA template is a three-dimensional network formed by tightly packed microspheres, it contains a large amount of air. These air bubbles can become significant obstacles to the permeation of the precursor solution, leading to incomplete filling and potentially forming pore defects. Furthermore, it also helps degas the mixed solvent. The solution itself may dissolve trace amounts of gas, which may precipitate and form bubbles during subsequent processing. Vacuum settling can remove these gases, further improving the homogeneity and permeability of the solution.

[0053] In conjunction with the second aspect, in some embodiments provided in this application, the drying temperature is 50~70°C. Drying within this temperature range allows for the smooth removal of the low-boiling-point solvent (methanol), preventing structural damage; it also maintains the supporting role of the high-boiling-point solvent (ethylene glycol), supporting the skeletal structure. Methanol has a boiling point of 65°C; setting the drying temperature within this range precisely covers the boiling point of methanol, ensuring that methanol is effectively converted to a gaseous state and removed. Ethylene glycol, with a boiling point as high as 197°C, has a very low evaporation rate within this temperature range. It supports the initial gel network formed by the precursor, preventing it from collapsing due to the large capillary forces after methanol evaporation.

[0054] In conjunction with the second aspect, in some embodiments provided in this application, the drying process takes 24-36 hours. This time range ensures a low evaporation rate and minimizes capillary stress. During the drying of porous gels, the greatest destructive force comes from the capillary stress generated during liquid evaporation. Sufficient drying time allows the solvent evaporation front to advance slowly, giving the gel skeleton enough time to elastically deform and rearrange, thereby safely releasing internal stress and effectively preventing cracking and collapse. Furthermore, it allows for deep solvent removal. If drying is incomplete, residual solvent will decompose or carbonize violently during subsequent high-temperature calcination, not only generating significant destructive force but also potentially introducing carbon impurities and contaminating the catalyst.

[0055] In conjunction with the second aspect, in some embodiments provided in this application, the preparation method of the polymethyl methacrylate microsphere template includes: mixing methyl methacrylate with deionized water, heating to 80-90°C under stirring, adding potassium persulfate aqueous solution, continuing the reaction for 2-3 hours, and then filtering, centrifuging, washing and drying to obtain the polymethyl methacrylate microsphere template.

[0056] By employing an aqueous environment of 80–90°C and initiating the polymerization of methyl methacrylate (PMMA) with potassium persulfate, the sphericity and particle size distribution of PMMA microspheres can be effectively controlled. Following filtration, centrifugation, and drying, a PMMA microsphere template with a regular structure and good monodispersity can be obtained. This preparation process is stable and highly reproducible, providing a uniform and size-controllable template foundation for the subsequent construction of perovskite catalysts with a three-dimensional ordered macroporous structure. This ensures that the final purification material possesses a regular pore structure and excellent mass transfer performance.

[0057] S300, subjected to calcination treatment In this step, the impregnation intermediate is calcined to obtain the purified material.

[0058] In conjunction with the second aspect, in some embodiments provided in this application, the calcination includes a first calcination and a second calcination. By employing a two-stage calcination process, the complete and stable removal of organic components can be achieved. The first calcination specifically targets the decomposition and oxidation of all organic matter (PMMA template, ethylene glycol solvent, and possible complexes). The second calcination focuses on the crystallization of the inorganic catalyst framework. Furthermore, crystal growth and phase transitions can be precisely controlled. The activity of the catalyst is closely related to its crystal phase; the second high-temperature calcination can independently optimize temperature and time to generate the target crystal phase and control grain size, avoiding over-sintering, thereby obtaining a high specific surface area and high catalytic activity.

[0059] In conjunction with the second aspect, in some embodiments provided in this application, the first calcination procedure is set to raise the temperature to 250-300°C at a rate of 1-2°C / min and calcinate for 2-4 hours. This limited first calcination procedure ensures the safe and thorough removal of organic matter without damaging the framework structure. The slow heating ensures that the decomposition and oxidation processes of PMMA and ethylene glycol are gradual and controllable. The target temperature range is higher than the solvent boiling point but lower than the framework sintering temperature, ensuring complete solvent removal. Sufficient calcination time ensures deep and complete removal of the template.

[0060] In conjunction with the second aspect, in some embodiments provided in this application, the second calcination procedure is set to a heating rate of 1~2°C / min to 600~800°C for 4~6 hours. This limited second calcination procedure allows the amorphous framework to be transformed into a high-performance catalyst with the target crystalline phase, high specific surface area, and excellent stability while maintaining the macroporous structure. The heating rate (1~2°C / min) allows for a smooth transition to high temperatures, minimizing stress during the crystallization process. The phase transition from amorphous to crystalline is accompanied by volume changes. Slow heating allows the phase transition to occur more uniformly throughout the sample, avoiding internal stress caused by rapid local crystallization. Calcination at 600~800°C allows for sufficient crystallization of the catalyst framework; this temperature range is typical for most metal oxides to form stable, target crystalline phases. Furthermore, over-sintering can be avoided. If the temperature is too low, crystallization will be incomplete and the catalytic activity will be low; if the temperature is too high (e.g., >900°C), the grains will grow rapidly and sinter, causing the walls of the macroporous framework to become denser, the pore size to shrink, and the specific surface area to drop sharply, thereby reducing the catalytic performance.

[0061] Thirdly, this application provides an application of the aforementioned in-vehicle purification material, characterized in that the in-vehicle purification material is used for in-vehicle air purification.

[0062] This application applies the purification material to in-vehicle air purification, which can fully utilize its three-dimensional ordered macroporous structure and high catalytic activity to efficiently degrade various volatile organic compounds (VOCs) such as benzene, toluene, formaldehyde, and acetaldehyde in the vehicle air conditioning system or air purification device, converting them into harmless carbon dioxide and water at a lower ignition temperature, thereby significantly improving the air quality inside the vehicle, meeting the relevant national standards, and possessing the advantages of long-lasting purification with resistance to poisoning and good stability.

[0063] Furthermore, the purification material obtained above is coated onto the filter element of the vehicle's air conditioning system to form a catalytic purification functional layer. Considering that the temperature environment required for the catalyst to exert its optimal catalytic activity is approximately 300°C, a corresponding heating unit needs to be configured within the air conditioning system to achieve this temperature condition. Specifically: 1) In traditional fuel vehicles, the heating system mainly relies on the waste heat of the engine cycle, and the air outlet temperature is usually not higher than 100°C, which is difficult to directly meet the ignition temperature requirements of the catalyst.

[0064] 2) In new energy vehicles, the advantage of electric energy can be utilized to achieve this by using active electric heating technology. For example, high-density PTC (positive temperature coefficient) ceramic heating elements can be integrated into the air conditioning duct to provide and maintain the required operating temperature for the catalyst, ensuring that its purification efficiency is fully utilized.

[0065] The technical solutions provided in this application will be described in detail below with reference to the embodiments.

[0066] Example 1 Embodiment 1 of this application provides an in-vehicle purification material La 0.99 Ca 0.01 Mn 0.9 Fe 0.1 O3 and its preparation method, the in-vehicle purification material includes perovskite metal oxide, the perovskite metal oxide having a three-dimensional ordered macroporous structure.

[0067] 1. Weigh lanthanum nitrate, calcium nitrate, manganese nitrate, and ferric nitrate according to stoichiometric ratios, and prepare a solution with the chemical composition La. 0.99 Ca 0.01 Mn 0.9 Fe 0.1 O3 precursor mixed salt solution.

[0068] 2. PMMA Template Synthesis: 120 mL of MMA and 440 mL of deionized water were added to a four-necked round-bottom flask. The mixture was stirred at 300 rpm and heated to 80°C. Simultaneously, 0.6 g of potassium persulfate was dissolved in deionized water and heated to 80°C. This solution was added to the flask, and the mixture was stirred continuously for 2 hours. The product was filtered through a microporous membrane. The resulting emulsion was centrifuged at 3000 rpm, the supernatant was discarded, and the precipitated PMMA microspheres were dried at 60 °C to obtain the PMMA template.

[0069] 3. Synthesis of in-vehicle air purification material: The aforementioned mixed salt solution was dissolved in a mixed solvent of methanol and ethylene glycol in a volume ratio of 1:4, and stirred at 30°C until completely dissolved. Then, a PMMA template was immersed in the metal salt solution and placed in a vacuum drying oven for 12 hours. The product was then filtered through a Buchner funnel and dried in an oven at 50°C for 36 hours to obtain an impregnation intermediate. The impregnation intermediate was calcined at 250°C for 4 hours under air atmosphere at a heating rate of 1°C / min; then calcined at 600°C for 6 hours at a further heating rate of 1°C / min to obtain La. 0.99 Ca 0.01 Mn 0.9 Fe 0.1 O3, of which La 0.99 Ca 0.01 Mn 0.9 Fe 0.1 The pore size of O3 is 100 nm; the pore volume is 0.1 cm³ / g; and the specific surface area is 30 m². 2 / g.

[0070] 4. Evaluation of Catalyst Performance of In-Vehicle Air Purification Materials: Referring to GB / T 27630-2011 "Guidelines for Air Quality Evaluation in Passenger Cars," samples were taken from the vehicle interior. After activating the catalytic purification system for 10 minutes, samples were taken again. The test results for benzene, toluene, xylene, ethylbenzene, styrene, formaldehyde, acetaldehyde, and acrolein, which are subject to standard controls, are shown in Table 1. Table 1

[0071] Note: ND indicates not detected.

[0072] Example 2 Embodiment 2 of this application provides an in-vehicle purification material La 0.7 Ba 0.3 Mn 0.1 Fe 0.9 O3 and its preparation method, the in-vehicle purification material includes perovskite metal oxide, the perovskite metal oxide having a three-dimensional ordered macroporous structure.

[0073] 1. Weigh lanthanum nitrate, barium nitrate, manganese nitrate, and ferric nitrate according to stoichiometric ratios to prepare a solution with the chemical composition La. 0.7 Ba 0.3 Mn 0.1 Fe 0.9 O3 precursor mixed salt solution.

[0074] 2. PMMA Template Synthesis: 120 mL of MMA and 440 mL of deionized water were added to a four-necked round-bottom flask. The mixture was stirred at 300 rpm and heated to 90°C. Simultaneously, 0.6 g of potassium persulfate was dissolved in deionized water and heated to 90°C. This solution was added to the flask, and the mixture was stirred continuously for 3 hours. The product was filtered through a microporous membrane. The resulting emulsion was centrifuged at 3000 rpm, the supernatant was discarded, and the precipitated PMMA microspheres were dried at 70 °C to obtain the PMMA template.

[0075] 3. Synthesis of in-vehicle air purification material: According to the molar ratio of the chemical formula, the above-mentioned precursor mixed salt solution was dissolved in a methanol and ethylene glycol mixture (methanol to ethylene glycol volume ratio 1:5), and stirred at 50°C until completely dissolved. Then, the PMMA template was immersed in the metal salt solution and placed in a vacuum drying oven for 24 hours. The product was then filtered through a Buchner funnel and dried in an oven at 70°C for 24 hours to obtain the impregnation intermediate. The impregnation intermediate was calcined in air at a heating rate of 2°C / min to 300°C for 2 hours; then calcined again at 2°C / min to 800°C for 4 hours to obtain La. 0.7 Ba 0.3 Mn 0.1 Fe 0.9 O3, of which La 0.7 Ba 0.3 Mn 0.1 Fe 0.9 The pore size of O3 is 300 nm; the pore volume is 0.3 cm³ / g; and the specific surface area is 50 m². 2 / g.

[0076] 4. The catalyst performance evaluation of the purification material was the same as in Example 1, and the test results are shown in Table 2: Table 2

[0077] Note: ND indicates not detected.

[0078] Example 3 Embodiment 2 of this application provides an in-vehicle purification material La 0.85 Sm 0.15 Mn 0.5 Fe 0.5O3 and its preparation method, the in-vehicle purification material includes perovskite metal oxide, the perovskite metal oxide having a three-dimensional ordered macroporous structure.

[0079] 1. Weigh lanthanum nitrate, samarium nitrate, manganese nitrate, and ferric nitrate according to stoichiometric ratios to prepare a solution with the chemical composition La. 0.85 Sm 0.15 Mn 0.5 Fe 0.5 O3 precursor mixed salt solution.

[0080] 2. PMMA Template Synthesis: 120 mL of MMA and 440 mL of deionized water were added to a four-necked round-bottom flask. The mixture was stirred at 300 rpm and heated to 85°C. Simultaneously, 0.6 g of potassium persulfate was dissolved in deionized water and heated to 85°C. This solution was added to the flask, and the mixture was stirred continuously for 3 hours. The product was filtered through a microporous membrane. The resulting emulsion was centrifuged at 3000 rpm, the supernatant was discarded, and the precipitated PMMA microspheres were dried at 65°C to obtain the PMMA template.

[0081] 3. Synthesis of in-vehicle air purification material: According to the molar ratio of the chemical formula, the above-mentioned precursor mixed salt solution was dissolved in a mixture of methanol and ethylene glycol (volume ratio 1:4) and stirred at 40°C until completely dissolved. Then, the PMMA template was immersed in the metal salt solution and placed in a vacuum drying oven for 18 hours. The product was then filtered through a Buchner funnel and dried in an oven at 60°C for 30 hours to obtain an impregnation intermediate. The impregnation intermediate was calcined in air at a heating rate of 1.5°C / min to 280°C for 3 hours. Then, the temperature was further increased to 700°C at 1.5°C / min and calcined for 5 hours to obtain La. 0.85 Sm 0.15 Mn 0.5 Fe 0.5 O3, of which La 0.85 Sm 0.15 Mn 0.5 Fe 0.5 The pore size of O3 is 200 nm; the pore volume is 2 cm³. 3 / g; specific surface area is 100 m² 2 / g.

[0082] 4. The performance evaluation of the catalyst for the in-vehicle air purification material is the same as in Example 1, and the test results are shown in Table 3: Table 3

[0083] Note: ND indicates not detected.

[0084] Example 4 Example 4 of this application provides an in-vehicle purification material, which is similar to Example 1, except that in the process of preparing the in-vehicle purification material, the impregnation intermediate is directly calcined once at a rate of 5°C / min from room temperature to 700°C.

[0085] The catalyst performance of the in-vehicle purification material in Example 4 was evaluated, and the results were the same as in Example 1. The test results are shown in Table 4. Table 4

[0086] Note: ND indicates not detected.

[0087] Comparative Example 1 Comparative Example 1 of this application provides an in-vehicle purification material, similar to Example 1, except that it uses a traditional co-precipitation method and the same metal salt precursor (La) as Example 1. 0.99 Ca 0.01 Mn 0.9 Fe 0.1 O3) was used to prepare perovskite catalysts without using PMMA templates.

[0088] The catalyst performance of the in-vehicle purification material in Comparative Example 1 was evaluated, and the results were the same as in Example 1. The test results are shown in Table 5. Table 5

[0089] Note: ND indicates not detected.

[0090] Comparative Example 2 Comparative Example 2 of this application provides an in-vehicle air purification material by altering the chemical composition of perovskite, such as preparing a perovskite material with the chemical formula LaMn. 0.8 Fe 0.2 O3. That is, without A-site doping (M=0, x=0), the preparation method of this in-vehicle purification material is similar to that in Example 1.

[0091] The catalyst performance of the in-vehicle purification material in Comparative Example 2 was evaluated, and the results were the same as in Example 1. The test results are shown in Table 6. Table 6

[0092] Note: ND indicates not detected.

[0093] As can be seen from Tables 1-6, the in-vehicle purification materials of Examples 1-4 have good overall catalytic performance. Comparative Example 1, due to the use of the traditional coprecipitation method without the use of PMMA template, suffers from drawbacks such as low mass transfer efficiency and difficulty in controlling component and phase purity.

[0094] Comparative Example 2 suffers from defects such as poor lattice oxygen mobility, easy loss of active sites, and easy sintering phase transformation due to the lack of oxygen vacancies introduced by M (such as Ca, Ba, Sm) doping.

[0095] In summary, the purification material provided in this application is a perovskite-type metal oxide. This perovskite-type metal oxide has a three-dimensional ordered macroporous structure with a high specific surface area, pore volume, and ordered channels, which is conducive to the diffusion of reactant gases and improves the reaction rate. The active components are uniformly dispersed on the surface of the channels in the form of nanoparticles, avoiding the aggregation problem of traditional methods and exposing more active sites, thereby improving the catalytic activity and anti-poisoning performance of the purification material and achieving efficient purification of various VOCs in the vehicle.

[0096] In the description of this specification, the references to terms such as "one embodiment / mode," "some embodiments / modes," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment / mode or example is included in at least one embodiment / mode or example of this application. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment / mode or example. Moreover, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments / modes or examples. Furthermore, without contradiction, those skilled in the art can combine and integrate the different embodiments / modes or examples described in this specification, as well as the features of different embodiments / modes or examples.

[0097] It should be noted that in this application, relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element. In this application, "a plurality of" means at least two, such as two, three, etc., unless otherwise expressly specified.

[0098] The above description is merely a specific embodiment of this application, enabling those skilled in the art to understand or implement this application. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of this application. Therefore, this application is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features claimed herein.

Claims

1. An in-vehicle purification material, characterized by comprising: The vehicle interior purification material comprises a perovskite metal oxide having a three-dimensionally ordered macroporous structure.

2. The in-vehicle purification material according to claim 1, wherein The chemical formula of the perovskite type metal oxide is La 1-x M x Mn y Fe 1-y O3, wherein M includes one of Ca, Ba and Sm, X=0.01-0.3, and y=0.1-0.

9.

3. The in-vehicle purification material according to claim 2, wherein The perovskite metal oxide has a pore size of 100-300 nm; and / or, The perovskite metal oxide has a pore volume of 0.1-2 cm³ / g; and / or, The specific surface area of the perovskite metal oxide is 30 to 100 m 2 / g.

4. A method for producing the interior purification material according to any one of claims 1 to 3, characterized by, The vehicle interior purification material comprises a perovskite metal oxide having a three-dimensionally ordered macroporous structure. The La salt, the M salt, the Mn salt, the Fe salt and a solvent are mixed to obtain a mixed salt solution, wherein M comprises one of Ca, Ba and Sm; The polymethyl methacrylate microsphere template is immersed in the mixed salt solution, and after standing and filtering, the immersed intermediate is obtained by drying treatment. The immersed intermediate is calcined to obtain the purification material.

5. The production method according to claim 4, wherein The solvent comprises a mixture of methanol and ethylene glycol; and / or, The volume ratio of the methanol to the ethylene glycol is 1: (3-5).

6. The production method according to claim 4, wherein The temperature of the mixing treatment is 30-50°C; and / or, The standing is performed in a vacuum environment, and the standing time is 12-24 h; and / or, The temperature of the drying treatment is 50-70°C; and / or, The drying treatment time is 24-36 h.

7. The production method according to claim 4, wherein The calcination comprises first calcination and second calcination.

8. The production method according to claim 7, wherein The first calcination is performed at a temperature rising rate of 1-2°C / min to 250-300°C for 2-4 h; and / or, The second calcination is performed at a temperature rising rate of 1-2°C / min to 600-800°C for 4-6 h.

9. The production method according to claim 4, wherein The preparation method of the polymethyl methacrylate microsphere template comprises the following steps: mixing methyl methacrylate and deionized water, stirring and heating to 80-90°C, adding potassium persulfate aqueous solution, continuously reacting for 2-3 h, and then filtering, centrifuging, washing and drying to obtain the polymethyl methacrylate microsphere template.

10. Use of the in-vehicle purification material according to any one of claims 1 to 3, characterized by The vehicle interior purification material is applied to vehicle interior air purification.

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