Odor-eliminating catalytic material, and preparation method therefor and use thereof

Abstract

The present application provides an odor-eliminating catalytic material, and a preparation method therefor and a use thereof. The odor-eliminating catalytic material of the present application comprises a honeycomb substrate. The honeycomb substrate is loaded with a hydrogen-type molecular sieve active component and an oxygen vacancy-type active component.

Description

A deodorizing catalytic material, its preparation method and application

[0001] Cross-reference of related applications

[0002] This application claims priority to Chinese Patent Application No. 202510075058.0, filed on January 16, 2025, entitled "A Deodorizing Catalytic Material and Its Preparation Method and Application", the entire contents of which are incorporated herein by reference. Technical Field

[0003] This application belongs to the field of catalyst technology, specifically relating to a deodorizing catalytic material, its preparation method, and its application. Background Technology

[0004] Refrigeration equipment, such as refrigerators, is an essential household appliance that greatly improves people's quality of life due to its excellent performance in food storage and preservation. However, the problem of odors inside refrigerators has always been a source of frustration for users during daily use.

[0005] The sources of odors inside refrigerators are diverse and complex, primarily depending on the type of food stored and its preservation conditions. These odor substances have varied molecular structures and physicochemical properties, placing highly complex performance requirements on catalysts. However, existing catalysts, due to their selectivity and specificity, are typically only effective against certain specific odor components, making it difficult to cover all odor sources. Furthermore, the low temperatures inside refrigerators pose significant challenges to catalyst performance: on the one hand, the intermolecular forces of reactants are stronger at low temperatures, requiring higher energy to break them; on the other hand, the density of active sites on the catalyst surface decreases at low temperatures, significantly reducing surface activity and reaction rates. Therefore, achieving efficient odor removal in the low-temperature environment of a refrigerator requires overcoming the dual limitations of the complexity of odor types and the catalytic performance imposed by the low-temperature environment.

[0006] In summary, existing refrigerator odor control technologies are insufficient in adapting to complex odor types and low-temperature environments, failing to meet users' needs for cleanliness and long-lasting odor removal. Therefore, developing a catalyst that can function efficiently in low-temperature environments has become a key technological direction for solving the refrigerator odor problem. This catalyst not only needs to possess broad-spectrum odor-removing effects, capable of dealing with various odor molecules, but also needs to maintain high activity and long-term stability under low-temperature conditions, thereby effectively improving the user's refrigerator experience. Summary of the Invention

[0007] This application aims to at least solve one of the aforementioned technical problems existing in the prior art. To this end, this application provides a deodorizing catalyst material with a broad-spectrum deodorizing effect, capable of dealing with a variety of odor molecules, maintaining high activity and long-term stability under low-temperature conditions, and improving the user experience when used in refrigeration equipment.

[0008] This application also provides a method for preparing odor-neutralizing catalyst materials.

[0009] This application also provides a deodorizing module containing the deodorizing catalyst material of this application.

[0010] This application also provides a refrigeration device containing the odor-neutralizing catalyst material or odor-neutralizing module of this application.

[0011] The first aspect of this application provides a deodorizing catalytic material, including a honeycomb substrate, wherein the honeycomb substrate is loaded with a hydrogen-type molecular sieve active component and an oxygen vacancy-type active component.

[0012] One of the technical solutions in this application regarding odor-neutralizing catalyst materials has at least the following beneficial effects:

[0013] This application provides a deodorizing catalytic material that belongs to a system that combines oxygen vacancy mechanism and acid-base catalytic mechanism. It can not only remove various odors such as amines, thiols, and thioethers at the same time, but also exhibits excellent catalytic efficiency under low temperature conditions.

[0014] Catalysts typically exist in powder form, making direct use difficult. Loading catalyst powder onto a honeycomb substrate can reduce the amount of catalyst used and improve utilization; it can also reduce wind resistance and minimize performance impact.

[0015] According to some embodiments of this application, the mass of the hydrogen-type molecular sieve active component accounts for 2 wt% to 20 wt% of the mass of the honeycomb substrate.

[0016] According to some embodiments of this application, the mass of the hydrogen-type molecular sieve active component accounts for 5 wt% to 10 wt% of the mass of the honeycomb substrate.

[0017] According to some embodiments of this application, the active component of the hydrogen-type molecular sieve includes at least one of HZSM-5 molecular sieve and Beta molecular sieve.

[0018] According to some embodiments of this application, the average particle size D50 of the hydrogen-type molecular sieve is 100 nm to 5 μm.

[0019] According to some embodiments of this application, the average particle size D50 of the hydrogen-type molecular sieve is 500 nm to 2 μm.

[0020] According to some embodiments of this application, the oxygen vacancy-type active component is a metal oxide containing oxygen vacancies, and the metal oxide includes at least one of manganese oxide, copper oxide, iron oxide, and cerium oxide.

[0021] Acidic molecular sieves and manganese oxides modified with specific metal elements significantly improve sulfur poisoning caused by the odors of methanethiol and thioethers, greatly extending the catalyst's lifespan. The manganese oxides modified with specific metal elements contain a large number of oxygen vacancies, and the oxygen-vacancy-type active components exhibit excellent effects on trimethylamine and methanethiol.

[0022] According to some embodiments of this application, the metal oxide is a mixture of manganese oxide, copper oxide, and iron oxide.

[0023] According to some embodiments of this application, the mass of the oxygen vacancy-type active component accounts for 1 wt% to 10 wt% of the mass of the honeycomb substrate.

[0024] According to some embodiments of this application, the mass of the metal oxide having oxygen vacancies accounts for 2 wt% to 5 wt% of the mass of the honeycomb substrate.

[0025] According to some embodiments of this application, the hydrogen-type molecular sieve active component is connected to the honeycomb substrate by an adhesive, and the oxygen vacancy-type active component is distributed in the pores and on the surface of the hydrogen-type molecular sieve active component.

[0026] According to some embodiments of this application, the honeycomb substrate includes at least one of cordierite ceramic honeycomb, alumina honeycomb, aluminum metal honeycomb, and glass fiber honeycomb.

[0027] According to some embodiments of this application, the honeycomb substrate is cordierite ceramic honeycomb.

[0028] According to some embodiments of this application, the odor-removing catalyst achieves an optimal removal rate of more than 90% for three types of standard odor components (trimethylamine, methanethiol, and dimethyl disulfide) for 9 minutes.

[0029] The second aspect of this application provides a method for using a deodorizing catalyst material, comprising the following steps:

[0030] The honeycomb substrate was sequentially impregnated in hydrogen-type molecular sieve slurry and metal salt solution, and then calcined.

[0031] Alternatively, hydrogen-type molecular sieves loaded with metal oxides can be first prepared into a slurry and then dip-coated onto the honeycomb substrate.

[0032] One technical solution in the preparation method of the odor-neutralizing catalyst material of this application has at least the following beneficial effects:

[0033] To overcome the shortcomings of existing technologies, the method described in this application has a simple preparation process, requires no high temperature (maximum only 350℃), and has low energy consumption. It also eliminates the need for high pressure, ball milling, or other similar processes. No precious metals are added during the preparation process, keeping costs under control. Furthermore, it avoids the use of strong acids and alkalis, ensuring safe production.

[0034] The catalytic material prepared in this application can be used directly in low-temperature environments (including refrigeration equipment such as refrigerators) without additional heating or other treatment. Based on the structural characteristics (molecular size, electron gain and loss characteristics, etc.) of the target odor components, the method can be finely adjusted to design a composite catalyst with active oxygen vacancies and surface acidic sites. The two work synergistically to achieve efficient purification of food odors.

[0035] Catalysts typically have small particle sizes. To ensure catalyst performance, binders are inevitably used during the loading process, which can easily lead to the coating of active catalyst components, resulting in severe performance degradation. To address this issue, this application employs a two-step loading method with different processes: First, micron-sized molecular sieve powder is impregnated onto a ceramic honeycomb using a binder. After drying and curing, it is then impregnated in a metal salt solution, followed by drying and calcination to obtain the final deodorizing catalyst material. This method fully exposes the active catalyst components, ensuring performance. Furthermore, the adhesion of the catalytic coating can meet the requirements for long-term use in humid environments of refrigeration equipment.

[0036] According to some embodiments of this application, the components of the hydrogen-type molecular sieve slurry include the hydrogen-type molecular sieve, a binder, and a thickener.

[0037] According to some embodiments of this application, the solid content of the hydrogen-type molecular sieve slurry is 5 wt% to 35 wt%.

[0038] The solid content here refers to the amount of hydrogen molecular sieve added to the hydrogen molecular sieve slurry.

[0039] According to some embodiments of this application, the solid content of the hydrogen-type molecular sieve slurry is 15wt% to 25wt%.

[0040] According to some embodiments of this application, the adhesive includes at least one of silica sol, alumina sol, bentonite, sodium silicate, and aluminum dihydrogen phosphate.

[0041] According to some embodiments of this application, the adhesive is silica sol or bentonite.

[0042] According to some embodiments of this application, the adhesive has a solid content of 2wt% to 15wt%.

[0043] The solid content here refers to the amount of binder added to the hydrogen-type molecular sieve slurry.

[0044] According to some embodiments of this application, the adhesive has a solid content of 5 wt% to 10 wt%.

[0045] According to some embodiments of this application, the thickener includes at least one of sodium carboxymethyl cellulose (CMC), polyvinyl alcohol (PVA), xanthan gum, and sodium alginate.

[0046] According to some embodiments of this application, the thickener is sodium carboxymethyl cellulose or sodium alginate.

[0047] According to some embodiments of this application, the thickener has a solid content of 0.1 wt% to 2.0 wt%.

[0048] According to some embodiments of this application, the thickener has a solid content of 0.2 wt% to 1.0 wt%.

[0049] According to some embodiments of this application, the metal component of the metal salt solution includes at least one of manganese, copper, iron and cerium, and the metal salt includes at least one of nitrate, sulfate and acetate.

[0050] According to some embodiments of this application, the metal salt is a nitrate.

[0051] According to some embodiments of this application, the total concentration of the metal salt solution ranges from 0.1 mol / L to 5 mol / L.

[0052] According to some embodiments of this application, the total concentration of the metal salt solution ranges from 0.5 mol / L to 4 mol / L.

[0053] According to some embodiments of this application, the manganese salt content in the metal salt solution is 40wt% to 99wt%.

[0054] According to some embodiments of this application, the manganese salt content in the metal salt solution is 50wt% to 90wt%.

[0055] According to some embodiments of this application, after the honeycomb substrate is impregnated in hydrogen-type molecular sieve slurry, the honeycomb substrate is first taken out, excess slurry is blown off, and then dried and cured to obtain honeycomb ceramic loaded with molecular sieve.

[0056] According to some embodiments of this application, the drying and curing temperature is 60°C to 200°C.

[0057] According to some embodiments of this application, the drying and curing temperature is 100℃~150℃.

[0058] According to some embodiments of this application, the drying and curing time is 0.5h to 5h.

[0059] According to some embodiments of this application, the drying and curing time is 1 hour to 2 hours.

[0060] According to some embodiments of this application, the calcination temperature is 200°C to 350°C.

[0061] According to some embodiments of this application, the calcination temperature is 250°C to 300°C.

[0062] According to some embodiments of this application, the calcination time is 0.5h to 5h.

[0063] According to some embodiments of this application, the calcination time is 1h to 2h.

[0064] According to some embodiments of this application, the method for preparing the odor-neutralizing catalyst material involves first preparing a slurry of hydrogen-form molecular sieves loaded with metal oxides, and then dip-coating it onto the honeycomb substrate. That is, the hydrogen-form molecular sieves are first immersed in a metal salt solution, then dried, calcined, and mechanically pulverized to obtain hydrogen-form molecular sieves loaded with metal oxides, which are then prepared into a slurry and loaded onto the honeycomb carrier via dip-coating. This method may result in some catalytically active components being covered by the binder, but it is still possible to achieve the same technical effect by increasing the overall powder coating amount.

[0065] A third aspect of this application provides a deodorizing module, comprising the deodorizing catalytic material of the first aspect of this application or prepared by the method of the second aspect of this application.

[0066] One of the technical solutions in this application regarding the odor-eliminating module has at least the following beneficial effects:

[0067] The odor-removing module of this application achieves highly efficient odor removal in low-temperature environments such as refrigeration equipment through the synergistic effect of oxygen vacancies and acid-base catalysis, exhibiting excellent catalytic efficiency and long-term stability. The module employs an environmentally friendly and low-cost manufacturing process, avoiding the use of precious metals and strong acids and alkalis. Its design incorporates a honeycomb substrate, reducing catalyst usage and wind resistance while ensuring superior performance. Its customization capabilities allow for optimization based on different odor characteristics, meeting diverse needs and providing the home appliance industry with an efficient and economical odor-removing solution.

[0068] The fourth aspect of this application provides a refrigeration device, wherein the refrigeration device is provided with an odor-removing module according to the third aspect of this application.

[0069] The low internal temperature of refrigerated equipment (such as refrigerators) limits the effectiveness of conventional catalysts. The refrigeration equipment of this application, by incorporating a deodorizing module, can efficiently remove various odors inside the refrigeration equipment, including trimethylamine, methanethiol, and dimethyl disulfide, significantly improving the storage environment and the freshness of food. The deodorizing module exhibits excellent catalytic performance at low temperatures, requiring no additional heating or complex operation, and possesses long-lasting and stable odor removal capabilities. Simultaneously, the module uses environmentally friendly materials and low-energy-consumption processes, aligning with the development trend of green home appliances and effectively meeting consumers' demand for high-quality refrigeration equipment.

[0070] According to some embodiments of this application, the refrigeration equipment includes a household refrigerator. Attached Figure Description

[0071] Figure 1 shows the microstructure of HZSM-5 molecular sieve.

[0072] Figure 2 shows the morphology of the odor-neutralizing catalyst prepared in Comparative Example 1.

[0073] Figure 3 shows the morphology of the odor-neutralizing catalyst prepared in Comparative Example 2.

[0074] Figure 4 is a morphology diagram of the odor-neutralizing catalyst material prepared in Example 1.

[0075] Figure 5 shows the morphology of the odor-neutralizing catalyst prepared in Comparative Example 6.

[0076] Figure 6 is a morphology diagram of the odor-neutralizing catalyst material prepared in Comparative Example 7.

[0077] Figure 7 is a schematic diagram of the odor-neutralizing catalyst material after the cross-sectional test in Example 1. Detailed Implementation

[0078] The following are specific embodiments of this application, and the technical solutions of this application will be further described in conjunction with the embodiments, but this application is not limited to these embodiments.

[0079] In a first aspect, some embodiments of this application provide a deodorizing catalytic material, comprising a honeycomb substrate on which oxygen vacancy-type active components and hydrogen-type molecular sieve active components are loaded.

[0080] It is understandable that the low ambient temperature inside refrigeration equipment limits the effectiveness of conventional catalysts. This application provides a deodorizing catalytic material, belonging to a system that synergistically utilizes oxygen vacancy and acid-base catalytic mechanisms. It can simultaneously remove various odors such as amines, thiols, and thioethers, and exhibits excellent catalytic efficiency under the low-temperature conditions of refrigeration equipment. In this deodorizing catalytic material, the surface of the hydrogen-form molecular sieve is acidic, showing excellent effects on thioethers (belonging to the broad Lewis base category); the oxygen vacancy-type active component shows excellent effects on trimethylamine and methanethiol.

[0081] Catalysts typically exist in powder form, making direct use difficult. Loading catalyst powder onto a honeycomb substrate can reduce the amount of catalyst used and improve utilization; it can also reduce wind resistance and minimize performance impact.

[0082] In conjunction with the first aspect, in some embodiments of this application, the active component of the hydrogen-type molecular sieve includes at least one of HZSM-5 molecular sieve and Beta molecular sieve.

[0083] HZSM-5 molecular sieve, a type of crystalline aluminosilicate zeolite, boasts extremely wide-ranging properties and applications. Primarily composed of silicon, aluminum, and oxygen, it possesses a unique two-dimensional pore structure with a silicon-to-aluminum ratio ranging from 200 to 1000. Its moderate pore size effectively filters molecules, enabling precise separation of reactants and products. Furthermore, HZSM-5 molecular sieve exhibits excellent thermal and hydrothermal stability, maintaining its performance even under high-temperature and humid conditions.

[0084] Beta zeolites, also known as beta zeolites or β-zeolites, are molecular sieve materials with a unique three-dimensional pore structure. They are primarily composed of silicon (Si) and aluminum (Al) linked by oxygen bridges, forming a framework structure with a regular pore system. Due to their excellent adsorption, separation, and catalytic properties, beta zeolites have wide applications in petroleum processing, chemical catalysis, and gas separation. Beta zeolites possess a unique three-dimensional twelve-membered ring pore structure, which facilitates the efficient diffusion and adsorption of molecules within the pores. The strong acidity and unique pore structure of beta zeolites enable them to exhibit high catalytic activity and selectivity in many chemical reactions.

[0085] In conjunction with the first aspect, in some embodiments of this application, the mass of the hydrogen-type molecular sieve active component accounts for 2 wt% to 20 wt% of the mass of the honeycomb substrate.

[0086] When the active component of the hydrogen-form molecular sieve accounts for 2wt% to 20wt% of the mass of the honeycomb ceramic substrate, it can effectively exert its acidic sites to catalyze the removal of sulfide-based odors, while ensuring excellent adhesion of the active component to the honeycomb ceramic surface. It should be noted that since the thickness of the molecular sieve coating is approximately 0.05mm to 0.1mm, compared to the approximately 1.3mm pore side length of the honeycomb ceramic, the coating thickness has a negligible impact on wind resistance. If it is below 2wt%, the insufficient number of acidic active sites will lead to a decrease in the adsorption and catalytic capacity for odor molecules; if it is above 20wt%, the excessive coating thickness will lead to the risk of cracking or powdering, increasing costs, or requiring an increased proportion of binder to ensure adhesion, resulting in severe coverage of active sites and reduced catalytic performance. Therefore, this loading range represents the optimal balance between performance, stability, and cost.

[0087] In conjunction with the first aspect, in some embodiments of this application, the mass of the hydrogen-type molecular sieve active component accounts for any value or a range of any two of 2wt%, 5wt%, 8wt%, 10wt%, 12wt%, 15wt%, 18wt%, and 20wt% of the mass of the honeycomb substrate, for example, 5wt% to 10wt%.

[0088] In conjunction with the first aspect, in some embodiments of this application, the average particle size D50 of the hydrogen-type molecular sieve is 100 nm to 5 μm.

[0089] When the average particle size (D50) of hydrogen-form molecular sieves is between 100 nm and 5 μm, a high specific surface area and good dispersibility can be achieved, thereby enhancing the adsorption and catalytic efficiency for odor molecules. If the particle size is below 100 nm, the molecular sieve particles are prone to agglomeration, leading to reduced dispersibility and weakening the effect of the active components. If the particle size is above 5 μm, the specific surface area decreases, the number of active components decreases, and the catalytic efficiency declines. Therefore, a particle size within this range can achieve an optimal balance between specific surface area, dispersibility, and material stability.

[0090] In conjunction with the first aspect, in some embodiments of this application, the average particle size D50 of the hydrogen-type molecular sieve is any value of 100nm, 500nm, 1μm, 2μm, 3μm, 4μm, 5μm or a range of any two of them, for example, 500nm to 2μm.

[0091] In conjunction with the first aspect, in some embodiments of this application, the oxygen vacancy-type active component is a metal oxide containing oxygen vacancies, the metal oxide including at least one of manganese oxide, copper oxide, iron oxide and cerium oxide.

[0092] Acidic molecular sieves and manganese oxides modified with specific metal elements also significantly improve sulfur poisoning caused by the odors of methanethiol and thioethers, greatly extending the catalyst's lifespan. The manganese oxides modified with specific metal elements contain a large number of oxygen vacancies, and the oxygen-vacancy-type active components exhibit excellent effects on trimethylamine and methanethiol.

[0093] In conjunction with the first aspect, in some embodiments of this application, the metal oxide is a mixture of oxides of manganese, copper, and iron.

[0094] In conjunction with the first aspect, in some embodiments of this application, the metal oxide is a mixture of manganese oxide and copper oxide.

[0095] In conjunction with the first aspect, in some embodiments of this application, the mass of the metal oxide accounts for 1 wt% to 10 wt% of the mass of the honeycomb substrate.

[0096] When the oxygen-vacancy type active component accounts for 1 wt% to 10 wt% of the honeycomb substrate mass, it ensures both sufficient exposure of the active component and the high efficiency and stability of the catalyst, thereby achieving efficient removal of odor molecules such as trimethylamine and methanethiol. If the loading is below 1 wt%, insufficient active component quantity will lead to a significant decrease in catalytic performance; if it is above 10 wt%, excessive active component accumulation on the surface will reduce the number of effectively usable active sites, resulting in reduced performance, while also increasing costs and increasing the risk of surface powder shedding. Therefore, the loading within this range represents the optimal balance between performance and cost.

[0097] In conjunction with the first aspect, in some embodiments of this application, the mass of the metal oxide accounts for any value or a range of any two of 1 wt%, 2 wt%, 3 wt%, 4 wt%, 5 wt%, 6 wt%, 7 wt%, 8 wt%, 9 wt%, and 10 wt% of the mass of the cellular substrate, for example, 2 wt% to 5 wt%.

[0098] In conjunction with the first aspect, in some embodiments of this application, the hydrogen-type molecular sieve active component is connected to the honeycomb substrate by an adhesive, and the oxygen vacancy-type active component is distributed in the pores and on the surface of the hydrogen-type molecular sieve active component.

[0099] The active components of the hydrogen-form molecular sieve are connected to the honeycomb substrate via a binder. Oxygen-vacancy-type active components are distributed within the pores and on the surface of the hydrogen-form molecular sieve active components, fully utilizing the acidic catalytic properties of the hydrogen-form molecular sieve and the excellent catalytic performance of the oxygen-vacancy-type active sites to achieve synergistic catalytic effects. The tight bonding between the hydrogen-form molecular sieve and the honeycomb substrate ensures the stability and high efficiency of the catalyst; while the distribution of oxygen-vacancy-type active components within and on the surface of the hydrogen-form molecular sieve effectively increases the density of active sites on the catalyst, enhancing its ability to remove various odor substances, especially maintaining excellent catalytic performance at low temperatures, thus improving the overall performance and service life of the material.

[0100] In conjunction with the first aspect, in some embodiments of this application, the cellular substrate includes at least one of cordierite ceramic cellular, alumina cellular, aluminum metal cellular, and glass fiber cellular.

[0101] Different materials used for honeycomb substrates each have their own advantages, as detailed below:

[0102] Cordierite ceramic honeycomb exhibits a low coefficient of thermal expansion and excellent thermal shock resistance, making it suitable for applications with large temperature fluctuations. Its moderate mechanical strength meets the loading requirements of general catalytic materials.

[0103] Alumina honeycomb has a high specific surface area, which allows for more active components to be used for catalyst support. It also exhibits good thermal stability, making it suitable for applications requiring high-temperature processing.

[0104] Aluminum honeycomb metal exhibits excellent thermal conductivity, enabling rapid heat transfer and enhancing catalytic reaction rates. It also boasts high mechanical strength and structural stability, making it suitable for applications requiring high strength and durability.

[0105] Fiberglass honeycomb is lightweight and highly corrosion-resistant, making it suitable for applications with high requirements for weight and chemical resistance. It also exhibits good thermal expansion properties, maintaining structural stability at various temperatures.

[0106] The selection of the aforementioned substrate materials can be flexibly adjusted according to actual application requirements, thereby achieving the best balance in terms of catalytic performance, durability, stability, and cost.

[0107] In conjunction with the first aspect, in some embodiments of this application, the honeycomb substrate is cordierite ceramic honeycomb.

[0108] In conjunction with the first aspect, in some embodiments of this application, the optimal removal rate of the odor-neutralizing catalyst for three types of standard odor components (trimethylamine, methanethiol, and dimethyl disulfide) all reached greater than 90% within 9 minutes.

[0109] The odor-neutralizing catalyst achieved a removal rate of over 90% for three typical odor components—trimethylamine, methanethiol, and dimethyl disulfide—within 9 minutes, indicating that:

[0110] 1. The odor-neutralizing catalyst material has high efficiency:

[0111] The material can efficiently remove multiple major odor components in a short time, demonstrating the rapid reaction capability of the catalyst.

[0112] 2. Odor-neutralizing catalysts have a certain broad spectrum of applicability:

[0113] It can remove different types of odor molecules simultaneously, including amines (trimethylamine) and sulfides (methanethiol, dimethyl disulfide), indicating that its mechanism of action (such as the synergistic effect of oxygen vacancies and acidic active components) has broad applicability.

[0114] 3. The odor-neutralizing catalyst material has strong applicability:

[0115] This highly efficient odor removal capability is especially suitable for scenarios with high requirements for odor control, such as refrigeration equipment, and can significantly improve the user experience.

[0116] In a second aspect, some embodiments of this application provide a method for producing a deodorizing catalyst, comprising the steps of sequentially impregnating a honeycomb substrate in a hydrogen-type molecular sieve slurry and a metal salt solution followed by calcination;

[0117] Alternatively, hydrogen-type molecular sieves loaded with metal oxides can be prepared into a slurry and then dipped onto a honeycomb substrate.

[0118] Understandably, to overcome the shortcomings of existing technologies, the method in this application features a simple preparation process, requires no high temperatures (maximum only 350℃), and has low energy consumption. It also eliminates the need for high-pressure processes, ball milling, and other similar techniques. No precious metals are added during the preparation process, keeping costs under control. Furthermore, it avoids the use of strong acids and alkalis, ensuring safe production.

[0119] The catalytic material prepared in this application can be used directly in the refrigerated environment of a refrigerator without additional heating or other treatment. Based on the structural characteristics of the target odor components (molecular size, electron gain and loss characteristics, etc.), the method can be finely adjusted to design a composite catalyst with active oxygen vacancies and surface acidic sites. The two work synergistically to achieve efficient purification of food odors.

[0120] Catalysts typically have small particle sizes, and to ensure catalyst performance, binders are inevitably used during the loading process. However, this can easily lead to the coating of the active catalyst components, resulting in significant performance degradation. To address this issue, this application employs a two-step loading method with different processes: First, micron-sized molecular sieve powder is impregnated onto a ceramic honeycomb using a binder. After drying and curing, it is then impregnated in a metal salt solution, followed by drying and calcination to obtain the final odor-neutralizing catalyst material. This method fully exposes the active catalyst components, ensuring performance. Furthermore, the adhesion of the catalytic coating is strong enough to meet the requirements of long-term use of refrigeration equipment in humid environments.

[0121] It's important to note that the reason for first loading the molecular sieve is that the molecular sieve and ceramic honeycomb are elementally similar, both being oxides of Si and Al. Chemical bonds can be formed using binders such as silica sol and alumina sol, resulting in a very strong loading of the molecular sieve. Then, the sieve is impregnated with a salt solution, and during calcination, it decomposes in situ, forming a metal oxide with strong bonding on the surface. If the process were reversed, first impregnating with salt and calcining to form oxides such as manganese salts, it would be extremely difficult to load the molecular sieve onto them using a binder (because existing binders cannot form chemical bonds with MnO2, etc.). If metal oxides were loaded first, it was found that the molecular sieve could not be firmly loaded onto the surface, resulting in severe powder shedding.

[0122] In conjunction with the second aspect, in some embodiments of this application, the components of the hydrogen-type molecular sieve slurry include hydrogen-type molecular sieves, binders, and thickeners.

[0123] In conjunction with the second aspect, in some embodiments of this application, the active component of the hydrogen-type molecular sieve includes at least one of HZSM-5 molecular sieve and Beta molecular sieve.

[0124] In conjunction with the second aspect, in some embodiments of this application, the solid content of the hydrogen-type molecular sieve slurry is 5 wt% to 35 wt%.

[0125] It should be noted that the solid content here refers to the amount of hydrogen molecular sieve added to the hydrogen molecular sieve slurry, that is, the mass of hydrogen molecular sieve / (mass of hydrogen molecular sieve + mass of binder + mass of thickener + mass of deionized water).

[0126] In conjunction with the second aspect, in some embodiments of this application, the solid content of the hydrogen-type molecular sieve slurry is any value of 5wt%, 10wt%, 15wt%, 20wt%, 25wt%, 30wt%, 35wt%, or a range of any two, for example, 15wt% to 25wt%.

[0127] In conjunction with the second aspect, in some embodiments of this application, the adhesive includes at least one selected from silica sol, alumina sol, bentonite, sodium silicate, and aluminum dihydrogen phosphate.

[0128] It should be noted that suppliers usually provide the particle size range for silica sol and aluminum sol, which is generally within 10nm; while sodium silicate and aluminum dihydrogen phosphate are not actually particles, but are dispersed in solution in the form of molecules, and can be broadly regarded as nanoscale.

[0129] The use of binders is a major cause of catalyst performance degradation. In this application, the second step involves direct impregnation with a metal salt solution followed by calcination, which fundamentally avoids the use of binders, ensuring that the metal oxide catalyst can be directly exposed, thereby achieving more complete exposure of the active components.

[0130] In conjunction with the second aspect, in some embodiments of this application, the adhesive is silica sol or bentonite.

[0131] In conjunction with the second aspect, in some embodiments of this application, the adhesive has a solid content of 2wt% to 15wt%.

[0132] It should be noted that the solid content here refers to the amount of binder added to the hydrogen molecular sieve slurry, that is, the mass of binder / (mass of hydrogen molecular sieve + mass of binder + mass of thickener + mass of deionized water).

[0133] In conjunction with the second aspect, in some embodiments of this application, the solid content of the adhesive is any value or a range formed by any two of 2wt%, 3wt%, 4wt%, 5wt%, 6wt%, 7wt%, 8wt%, 9wt%, 10wt%, 11wt%, 12wt%, 13wt%, 14wt%, and 15wt%, for example, 5wt% to 10wt%.

[0134] In conjunction with the second aspect, in some embodiments of this application, the thickener includes at least one of sodium carboxymethyl cellulose (CMC), polyvinyl alcohol (PVA), xanthan gum, and sodium alginate.

[0135] In conjunction with the second aspect, in some embodiments of this application, the thickener is sodium carboxymethyl cellulose or sodium alginate.

[0136] In conjunction with the second aspect, in some embodiments of this application, the thickener has a solid content of 0.1 wt% to 2.0 wt%.

[0137] It should be noted that the solid content here refers to the amount of thickener added to the hydrogen molecular sieve slurry, that is, the mass of thickener / (mass of hydrogen molecular sieve + mass of binder + mass of thickener + mass of deionized water).

[0138] In conjunction with the second aspect, in some embodiments of this application, the thickener has a solid content of any value or a range formed by any two of 0.1wt%, 0.2wt%, 0.5wt%, 0.8wt%, 1.0wt%, 1.5wt%, and 2.0wt%, for example, 0.2wt% to 1.0wt%.

[0139] In conjunction with the second aspect, in some embodiments of this application, the metal component of the metal salt solution includes at least one of manganese, copper, iron and cerium, and the metal salt includes at least one of nitrate, sulfate and acetate.

[0140] In conjunction with the second aspect, in some embodiments of this application, the metal salt is a nitrate, specifically Mn(NO3)2, Cu(NO3)2·3H2O and Fe(NO3)3·9H2O.

[0141] In conjunction with the second aspect, in some embodiments of this application, the metal salt is a sulfate, specifically MnSO4, CuSO4, and Fe2(SO4)3.

[0142] In conjunction with the second aspect, in some embodiments of this application, the metal salt is an acetate, specifically Mn(CH3COO)2, Cu(CH3COO)2, and Fe(CH3COO)2.

[0143] In conjunction with the second aspect, in some embodiments of this application, the total concentration of the metal salt solution ranges from 0.1 mol / L to 5 mol / L.

[0144] In conjunction with the second aspect, in some embodiments of this application, the total concentration range of the metal salt solution is any value or a range formed by any two of the following: 0.1 mol / L, 0.5 mol / L, 1.0 mol / L, 1.5 mol / L, 2.0 mol / L, 2.5 mol / L, 3.0 mol / L, 3.5 mol / L, and 4 mol / L, for example, 0.5 mol / L to 4 mol / L.

[0145] In conjunction with the second aspect, in some embodiments of this application, the content of manganese salt in the metal salt solution is 40 wt% to 99 wt%.

[0146] In conjunction with the second aspect, in some embodiments of this application, the manganese salt content in the metal salt solution is any value of 40wt%, 50wt%, 60wt%, 70wt%, 80wt%, 90wt%, 99wt%, or a range of any two, for example, 50wt% to 90wt%.

[0147] In conjunction with the second aspect, in some embodiments of this application, after the honeycomb substrate is impregnated in a hydrogen-type molecular sieve slurry, the honeycomb substrate is first removed, excess slurry is blown off, and then dried and cured to obtain a honeycomb ceramic loaded with molecular sieve.

[0148] In conjunction with the second aspect, in some embodiments of this application, the drying and curing temperature is 60°C to 200°C.

[0149] In conjunction with the second aspect, in some embodiments of this application, the drying and curing temperature is any value or a range formed by any two of 60°C, 80°C, 100°C, 120°C, 150°C, 180°C, and 200°C, such as 100°C to 150°C.

[0150] In conjunction with the second aspect, in some embodiments of this application, the drying and curing time is 0.5h to 5h.

[0151] In conjunction with the second aspect, in some embodiments of this application, the drying and curing time is any value of 0.5h, 1h, 2h, 3h, 4h, 5h or a range of any two, such as 1h to 2h.

[0152] In conjunction with the second aspect, in some embodiments of this application, the calcination temperature is 200°C to 350°C.

[0153] In conjunction with the second aspect, in some embodiments of this application, the calcination temperature is any value of 200°C, 220°C, 250°C, 270°C, 300°C, 320°C, 350°C, or a range of any two, such as 250°C to 300°C.

[0154] In conjunction with the second aspect, in some embodiments of this application, the calcination time is 0.5h to 5h.

[0155] In conjunction with the second aspect, in some embodiments of this application, the calcination time is any value of 0.5h, 1h, 2h, 3h, 4h, 5h or a range of any two, such as 1h to 2h.

[0156] In conjunction with the second aspect, in some embodiments of this application, the method for preparing the odor-neutralizing catalyst material involves first preparing a slurry of hydrogen-form molecular sieves loaded with metal oxides, and then dip-coating it onto a honeycomb substrate. That is, the hydrogen-form molecular sieves are first immersed in a metal salt solution, then dried, calcined, and mechanically pulverized to obtain hydrogen-form molecular sieves loaded with metal oxides, which are then prepared into a slurry and loaded onto a honeycomb carrier via dip-coating. This method may result in some catalytically active components being covered by the binder, but it is still possible to achieve the same technical effect by increasing the overall powder coating amount.

[0157] In a third aspect, some embodiments of this application provide a deodorizing module, which is prepared from the deodorizing catalytic material of the first aspect of this application or the method of the second aspect of this application.

[0158] It is understood that the odor-removing module of this application achieves efficient odor removal in low-temperature environments such as refrigeration equipment through the synergistic effect of oxygen vacancies and acid-base catalysis, exhibiting excellent catalytic efficiency and long-term stability. The module employs an environmentally friendly and low-cost manufacturing process, avoiding the use of precious metals and strong acids and alkalis. Its design incorporates a honeycomb substrate, reducing both catalyst usage and wind resistance, ensuring superior performance. Its customization capabilities allow for optimization based on different odor characteristics, meeting diverse needs and providing the home appliance industry with an efficient and economical odor-removing solution. Specifically:

[0159] The odor removal module utilizes the synergistic effect of oxygen vacancy mechanism and acid-base catalysis mechanism to efficiently remove typical odor components such as trimethylamine, methanethiol, and dimethyl disulfide. It exhibits excellent catalytic efficiency in low-temperature environments (such as refrigerator compartments) to meet practical usage needs.

[0160] The odor-neutralizing module, based on manganese oxide modified with specific metal elements and acidic molecular sieves, effectively alleviates sulfur poisoning and extends catalyst lifespan. Simultaneously, the module's coating adhesion has been optimized, enabling long-term stable use in humid environments.

[0161] Furthermore, the odor-neutralizing module eliminates the need for precious metals, strong acids, and strong alkalis during its preparation, significantly reducing production costs and improving environmental friendliness. The module's design simplifies the application process, requiring no additional heating or complex processing, making it ready for immediate use and further reducing energy consumption and operating costs.

[0162] The odor-neutralizing catalyst is loaded onto a honeycomb substrate, achieving a modular structural design. This design not only reduces catalyst usage and improves utilization, but also lowers air resistance, adapts to the airflow characteristics inside refrigeration equipment, and ensures the efficient operation of the odor-neutralizing module.

[0163] The module design can be fine-tuned according to the characteristics of specific target odor components (such as molecular size and acidity / alkalinity), optimizing the ratio of oxygen vacancies to acidic sites to achieve targeted odor removal effects and meet the needs of different customers.

[0164] Thus, the development of the odor-eliminating module integrates high efficiency, long-lasting effectiveness, and economy, providing an innovative solution for odor treatment in low-temperature environments such as refrigeration equipment. It not only improves the user experience but also sets a new benchmark for odor management technology in the home appliance industry.

[0165] It should be noted that in this application, the odor-eliminating module is a component or device made of odor-eliminating catalytic material. In appliances such as refrigerators, the odor-eliminating module can typically be a complete unit, which can be installed in a certain location in the refrigerator (such as the refrigerator compartment, freezer compartment, etc.), and odor components in the air are brought into contact with the odor-eliminating catalytic material through air circulation, thereby purifying them.

[0166] It's understandable that an odor-eliminating module is not just about the catalytic material itself; it may also include an installation frame, airflow structure, and support components to ensure the odor-eliminating catalytic material functions efficiently in specific environments (such as inside a refrigerator). The odor-eliminating module is a complete system designed to maximize the contact between the odor-eliminating catalytic material and the air, thereby improving purification efficiency.

[0167] In a fourth aspect, some embodiments of this application provide a refrigeration device, which includes a deodorizing module as described in the third aspect of this application.

[0168] The refrigeration equipment disclosed in this application, through the inclusion of a deodorizing module, can efficiently remove various odors from the interior of the refrigeration equipment, including trimethylamine, methanethiol, and dimethyl disulfide, significantly improving the storage environment and the freshness of food. The deodorizing module exhibits excellent catalytic performance at low temperatures, requiring no additional heating or complex operation, and possesses long-lasting and stable odor removal capabilities. Furthermore, the module utilizes environmentally friendly materials and low-energy-consumption processes, aligning with the development trend of green home appliances and effectively meeting consumers' demand for high-quality refrigeration equipment.

[0169] The catalytic deodorizing module in this application, when used in refrigeration equipment, can reduce the odor level of food from level 4 or above to level 2 or below, achieving a significant deodorizing effect.

[0170] The synergistic mechanism of the active oxygen vacancy + surface acidic site composite catalyst proposed in this application has good universality and scalability. Suitable catalyst combination schemes can be designed according to the structural characteristics of the target odor molecules. The technology can be quickly promoted to scenarios such as dishwasher residual odor removal and oven odor purification.

[0171] The following will clearly and completely describe the concept and technical effects of this application in conjunction with embodiments, so as to fully understand the purpose, features and effects of this application. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Other embodiments obtained by those skilled in the art based on the embodiments of this application without creative effort are all within the scope of protection of this application.

[0172] In the description of this application, the terms "one embodiment," "some embodiments," "illustrative embodiment," "example," "specific example," or "some examples," etc., refer to specific features, structures, materials, or characteristics described in connection with that embodiment or example, which are included in at least one embodiment or example of this application. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0173] Unless otherwise specified, "room temperature" in this application means 25℃±5℃.

[0174] Unless otherwise specified, “about” in this application means that the allowable error is within ±2%.

[0175] Unless otherwise specified in the examples, the procedures should be performed under standard conditions or conditions recommended by the manufacturer. Reagents or instruments whose manufacturers are not specified are all commercially available products.

[0176] In this embodiment, the silica sol was purchased from Shandong Kehan ​​Silicon Source New Material Co., Ltd. Sodium carboxymethyl cellulose (CMC) was purchased from Maclean's, with a viscosity of 5000-15000 mPa·s. In actual use, there is no need to limit this viscosity range; commercially available products are generally suitable.

[0177] Example 1

[0178] A deodorizing catalytic material was prepared using a honeycomb ceramic substrate, on which oxygen vacancy-type active components and hydrogen-form molecular sieve active components were loaded. The specific preparation method is as follows:

[0179] The honeycomb substrate is cordierite ceramic honeycomb.

[0180] Weigh 15.0g of HZSM-5 molecular sieve, 5.0g of silica sol, 0.2g of CMC, and 79.8g of deionized water into a container, and mechanically stir at high speed until completely and uniformly dispersed to obtain molecular sieve slurry;

[0181] The honeycomb ceramic carrier is immersed in molecular sieve slurry, then removed and the excess slurry in the honeycomb ceramic pores is blown away with an air knife. It is then placed in a forced-air drying oven and dried at 120°C for 1 hour to obtain ceramic honeycomb blocks loaded with molecular sieve.

[0182] It should be noted that there are no special restrictions on the ratio of the honeycomb ceramic carrier to the molecular sieve slurry, as long as the slurry can completely submerge the ceramic blocks. The average particle size D50 of HZSM-5 molecular sieve is about 1 μm.

[0183] Weigh 53.7g of 50% Mn(NO3)2 solution, 29.0g of Cu(NO3)2·3H2O, and 12.1g of Fe(NO3)3·9H2O into a container, add deionized water to make the total solution volume 100mL, and stir mechanically until completely dissolved to obtain a metal salt solution with a concentration of 3mol / L, wherein the atomic ratio of Mn:Cu:Fe is 50:40:10;

[0184] The honeycomb ceramic carrier loaded with molecular sieves was immersed in a metal salt solution, then removed and the excess solution in the ceramic honeycomb pores was blown away with an air knife. It was then placed in a high-temperature forced-air drying oven and calcined at 300°C for 1 hour to obtain the deodorizing catalyst material.

[0185] It should be noted that the 50% Mn(NO3)2 solution is a mass concentration. Commercially available Mn(NO3)2 is generally a solution formed by dissolving 50 wt% of it in water, while Cu(NO3)2·3H2O and Fe(NO3)3·9H2O are both completely solids.

[0186] It should also be noted that the roles of each metal differ somewhat. Firstly, manganese oxide is generally a high-performance catalyst, and doping with low-valence metals is an effective way to introduce oxygen vacancies and improve its performance. In manganese oxide, Mn is typically in the +4 and +3 valence states, and introducing Cu... 2+ Elements can further improve performance. Additionally, the introduction of Fe... 3+ It has the same effect; in addition, Fe can alleviate the problem of catalyst poisoning and deactivation, and extend its service life. Therefore, using a combination of three metal elements yields better results.

[0187] It should also be noted that the calcination at 300℃ for 1 hour is because after impregnation with the metal salt, it still exists in the form of nitrate. The metal oxide is what ultimately acts as a catalyst, so high-temperature calcination in air is necessary to decompose the nitrate and generate the metal oxide.

[0188] Example 2

[0189] A deodorizing catalytic material was prepared. The difference between this material and Example 1 is that the molecular sieve is an H-type Bata molecular sieve, while the rest is the same as in Example 1.

[0190] Example 3

[0191] A deodorizing catalyst material was prepared. The difference from Example 1 is that the molecular sieve content in the molecular sieve slurry was reduced. The specific dosage is as follows: 10.0g of HZSM-5 molecular sieve, 5.0g of silica sol, 0.2g of CMC, and 84.8g of deionized water; the rest is the same as in Example 1.

[0192] Example 4

[0193] A deodorizing catalytic material was prepared. The difference between this material and Example 1 is that the binder in the molecular sieve slurry is bentonite, while the rest is the same as in Example 1.

[0194] Example 5

[0195] A deodorizing catalyst material was prepared. The difference from Example 1 is that the content of silica sol in the molecular sieve slurry is reduced. The specific dosage is: 15.0g of HZSM-5 molecular sieve, 2.0g of silica sol, 0.2g of CMC, and 82.8g of deionized water; the rest is the same as in Example 1.

[0196] Example 6

[0197] A deodorizing catalyst was prepared. The difference from Example 1 is that the concentration of the metal salt solution was reduced to 1.5 mol / L. The specific amounts were: 26.9 g of 50% Mn(NO3)2 solution, 14.5 g of Cu(NO3)2·3H2O, and 6.1 g of Fe(NO3)3·9H2O; the rest were the same as in Example 1.

[0198] Example 7

[0199] A deodorizing catalyst was prepared. The difference from Example 1 is that the metal salt solution does not contain iron salt. The specific amounts used are: 43.0 g of 50% Mn(NO3)2 solution and 36.3 g of Cu(NO3)2·3H2O (where the atomic ratio of Mn:Cu is 50:50); the rest is the same as in Example 1.

[0200] Example 8

[0201] A deodorizing catalyst was prepared. The difference from Example 1 is that the metal salt solution does not contain iron salt, and copper salt is replaced with cerium salt. The specific amounts are: 53.7g of 50% Mn(NO3)2 solution and 65.1g of Ce(NO3)3·6H2O (where the atomic ratio of Mn:Ce is 50:50). The rest is the same as in Example 1.

[0202] Comparative Example 1

[0203] A deodorizing catalytic material was prepared. The difference from Example 1 is that only molecular sieves are loaded on the ceramic honeycomb carrier, and no metal oxide catalyst is loaded. The rest is the same as in Example 1.

[0204] Comparative Example 2

[0205] A deodorizing catalytic material was prepared. The difference from Example 1 is that only metal oxide catalysts are loaded on the ceramic honeycomb carrier, and no molecular sieves are loaded. The rest is the same as in Example 1.

[0206] Comparative Example 3

[0207] A deodorizing catalytic material was prepared. The difference between this material and Example 1 is that the H-type molecular sieve is HY molecular sieve, while the rest is the same as in Example 1.

[0208] Comparative Example 4

[0209] A deodorizing catalytic material was prepared. The difference between this material and Example 1 is that the H-type molecular sieve is HSSZ-13 molecular sieve, while the rest is the same as in Example 1.

[0210] Comparative Example 5

[0211] A deodorizing catalytic material was prepared. The difference between this material and Example 1 is that the binder in the molecular sieve slurry is sodium silicate, while the rest is the same as in Example 1.

[0212] Comparative Example 6

[0213] A deodorizing catalyst material was prepared. The difference from Example 1 is that CMC was not added to the molecular sieve slurry. The specific dosage was: 15.0g of HZSM-5 molecular sieve, 5.0g of silica sol, and 80.0g of deionized water; the rest was the same as in Example 1.

[0214] Comparative Example 7

[0215] A deodorizing catalyst was prepared, differing from Example 1 in that the proportion of iron salt in the metal salt solution was increased to 40%, specifically: 43.0 g of 50% Mn(NO3)2 solution, 14.5 g of Cu(NO3)2·3H2O, and 48.5 g of Fe(NO3)3·9H2O (where the atomic ratio of Mn:Cu:Fe is 40:20:40); the rest was the same as in Example 1.

[0216] Comparative Example 8

[0217] A deodorizing catalyst material was prepared. The difference between this material and Example 1 is that the calcination temperature of the metal salt is 200°C, while the rest is the same as in Example 1.

[0218] Performance testing

[0219] The microstructure of HZSM5 molecular sieve was observed, as shown in Figure 1. Figure 1 shows that the HZSM5 molecular sieve crystals are approximately cubic in shape, with a size of about 1 μm.

[0220] Figure 2 shows the ceramic honeycomb block of the odor-neutralizing catalyst prepared in Comparative Example 1. The size of the ceramic honeycomb block is approximately 80*20*13mm. Comparative Example 1 was loaded with HZSM5 molecular sieve alone. As can be seen from Figure 2, the molecular sieve was uniformly coated on the inner and outer surfaces of the honeycomb ceramic without any pore blockage, and the sides were smooth and flat.

[0221] Figure 3 shows the ceramic honeycomb block of the odor-neutralizing catalyst prepared in Comparative Example 2. Comparative Example 2 is loaded with metal oxide alone. As can be seen from Figure 3, the entire module presents a relatively uniform gray-black color and there is no pore blockage.

[0222] Figure 4 is a physical image of the odor-neutralizing catalyst material prepared in Example 1. As can be seen from Figure 4, the color of the module is slightly darker than that in Comparative Example 2. This is because a layer of molecular sieve is impregnated on the surface of the honeycomb ceramic.

[0223] Figure 5 shows a physical image of the odor-neutralizing catalyst material prepared in Comparative Example 6. As can be seen from Figure 5, if CMC is not added to the molecular sieve slurry, its fluidity will be poor, which will easily cause the honeycomb ceramic to become clogged.

[0224] Figure 6 shows a physical image of the odor-neutralizing catalyst material prepared in Comparative Example 7. As can be seen from Figure 6, the proportion of Fe element has a great influence on the adhesion of the coating. When the proportion is too high, it is very easy to cause the coating to crack and peel off severely.

[0225] The loading of molecular sieves and metal oxides in the odor-neutralizing catalysts of each embodiment and comparative example was calculated by weighing.

[0226] The adhesion of the catalytic coating was determined by a cross-cut adhesion test.

[0227] Figure 7 is a schematic diagram of the odor-neutralizing catalyst material after the cross-cut adhesion test in Example 1. As can be seen from Figure 7, after the cross-cut adhesion test, the coating remained almost intact, corresponding to an adhesion strength of level 1 or higher, indicating that the material has a very strong adhesion to the honeycomb ceramic substrate.

[0228] The removal performance tests for three standard odor components (trimethylamine, methanethiol, and dimethyl disulfide) were conducted in a standard test chamber with a volume of 100L.

[0229] The specific testing procedure is as follows: First, place the odor-removing catalyst material in the middle of a 100L standard test chamber, and inject a certain amount of odor components into the chamber so that the initial concentration is about 10ppm. First, use a detection tube or gas chromatography-mass spectrometry (GC-MS) to measure the specific value of the initial concentration (C0, unit ppm). Then, turn on the circulation fan and test the remaining concentration C1 again after 9 minutes. The purification rate is calculated by the formula (C0-C1) / C0.

[0230] It should also be noted that the standard odor test was conducted in an environmental chamber at room temperature (25℃). The main purpose of this test is to quickly and easily determine the catalytic performance of the catalyst for various odors. The national standard GB21551.4-2010 requires refrigerator odor removal to be greater than 90% after 2 hours. A requirement of greater than 90% after 9 minutes can be considered a more stringent standard requirement.

[0231] The specific test results are shown in Table 1.

[0232] Table 1

[0233] As can be seen from Table 1:

[0234] In most embodiments, the purification rates of trimethylamine, methanethiol, and dimethyl disulfide were high, generally exceeding 90%, indicating that the odor-removing catalyst has a significant ability to remove multiple odors.

[0235] The purification efficiency of the comparative ratios was relatively low, especially for comparative ratios 5, 6, and 8, where the purification rates of the three odors dropped to below 75%, 63%, and 58%, respectively, indicating that the purification performance was significantly reduced when the optimal ratio was not met.

[0236] The purification rate of dimethyl disulfide in Comparative Example 2 was only 7%. The single metal oxide on the surface has almost no catalytic effect on sulfide-type odors, and a suitable molecular sieve is needed to achieve a synergistic effect.

[0237] Regarding Comparative Example 3, it should be noted that the selection of molecular sieves was based on two criteria: pore size and surface acidity. The target odor molecules to be treated had a size of approximately 0.5-0.7 nm. The HZSM-5 molecular sieve has a pore size of 0.5-0.6 nm, and the Beta molecular sieve has a pore size of 0.5-0.7 nm. The HSSZ-13 molecular sieve has a pore size of 0.38 nm, and the HY molecular sieve has a pore size of 0.74 nm.

[0238] According to the theory of shape-selective catalysis, only molecules whose size and shape match the pores of the molecular sieve and can diffuse into the pores can react. The poor performance of HY molecular sieves is also related to the type and strength of the acid on the sieve surface.

[0239] Regarding Comparative Example 5, it should be noted that the binder has two functions: first, to firmly adhere the molecular sieve to the ceramic honeycomb; second, to avoid encapsulating the active components of the molecular sieve and causing excessive performance loss.

[0240] When the coating is relatively thin, the bonding strength of sodium silicate is sufficient; however, when the molecular sieve loading is high, i.e., the molecular sieve coating thickness is large (approximately 50-100 μm), sodium silicate cannot effectively bond the molecular sieve, resulting in cracking and detachment. Therefore, the final catalyst powder loading decreases, the bonding strength is poor (see data in the table), and the performance deteriorates.

[0241] Regarding Comparative Example 6, it should be noted that CMC, as a thickener, ensures sufficient powder loading by adjusting the viscosity and flowability of the slurry in the formulation, without causing pore blockage in the ceramic honeycomb. Without CMC, the slurry viscosity is low, reducing the powder loading (see loading data in Table 1), and the slurry flowability deteriorates, causing many ceramic honeycomb pores to become blocked (as shown in Figure 5). The reduced total catalyst amount, coupled with pore blockage, decreases the contact area (opportunity) between the catalyst and the odor, thus degrading performance.

[0242] Although Comparative Example 7 has a high purification rate, its bonding strength is only level 5, which may cause it to detach during use, resulting in a shortened material lifespan.

[0243] Regarding Comparative Example 8, it should be noted that some nitrates were not completely decomposed under 200℃ conditions.

[0244] Most embodiments showed a bonding strength of grade 1 or 2, indicating that the catalytic coating had good adhesion and could be durable for a long time; however, comparative examples 5 and 6 showed a bonding strength of only grade 3 or 4, indicating that their service life would be significantly reduced in humid environments.

[0245] Furthermore, the odor-removing catalyst material from Example 1 was placed in the refrigerator compartment (temperature set at 2°C) to determine its purification effect on real food items with typical odors.

[0246] The odor level was determined by three professional odor assessors who evaluated and scored the odor (the final score was the average of the three scores). The assessment criteria followed the odor intensity grading method: Level 0 - odorless; Level 1 - barely perceptible odor; Level 2 - very weak odor but its nature can be discerned; Level 3 - easily perceptible odor; Level 4 - strong odor; Level 5 - extremely strong odor that is unbearable.

[0247] The test results are shown in Table 2.

[0248] Table 2

[0249] As can be seen from Table 2:

[0250] Under the low temperature of 2°C in the refrigerator, the odor-removing catalyst in Example 1 has a very significant purifying effect on typical odorous foods. The odor level of all foods has decreased from the initial level 3 and above (a strong odor that is clearly perceptible or even unbearable) to level 1-2 after purification (only barely perceptible or very weak odor).

[0251] It is particularly effective at purifying strong odors (such as jackfruit, hot pot base, and mixed odors), reducing the level from unbearable level 5 to level 1-2.

[0252] It is more effective at purifying mild odors (such as onions and leftovers), leaving the odor almost odorless (level 0-1) after purification.

[0253] The temperature in a refrigerator compartment is 2°C, and low temperatures often inhibit the activity of most conventional catalysts. The odor-neutralizing catalyst of this application still exhibits excellent purification performance in this environment, indicating that the synergistic effect of its oxygen vacancies and acidic sites can overcome temperature limitations and continuously and efficiently remove odors. This verifies the effectiveness of the material in a refrigerated environment, demonstrating its ability to function continuously at low temperatures, which aligns with the application scenarios of refrigeration equipment. This indicates that the odor-neutralizing catalyst of this application is suitable for use in refrigerators or other refrigeration equipment to remove odors from various ingredients, improve food preservation quality, and reduce the impact of unpleasant odors on the food storage environment. In particular, its removal effect on unpleasant odors (such as hot pot base, jackfruit, etc.) is outstanding, meeting the market demand for a fresh food storage environment.

[0254] The odor-neutralizing catalyst exhibits targeted effects against durian, jackfruit (primarily volatile sulfur compounds), onions (containing thiols and thioethers), and saury (volatile amines). The acidic molecular sieve preferentially adsorbs alkaline odors (such as volatile amines), while the oxygen vacancy active component efficiently catalyzes the decomposition of odor molecules.

[0255] The combined odor after all ingredients were mixed was reduced to level 1-2 after purification, indicating that the catalytic material has an inhibitory effect on the interaction between odor molecules (such as odor enhancement caused by cross-influence) and has the ability to handle complex mixed gases.

[0256] Test data shows that even in the high humidity environment of a refrigerator, the catalytic material maintains strong binding force and its performance does not significantly decrease, meeting the requirements for long-term use of household appliances. The food was purified without any residual unpleasant odor, verifying the thoroughness of the catalytic process.

[0257] The present application has been described in detail above with reference to the embodiments. However, the present application is not limited to the above embodiments. Within the scope of knowledge possessed by those skilled in the art, various changes can be made without departing from the spirit of the present application.

Claims

1. A deodorizing catalyst material, comprising a honeycomb substrate, wherein, The honeycomb substrate is loaded with hydrogen-type molecular sieve active components and oxygen vacancy-type active components.

2. The odor-neutralizing catalyst material according to claim 1, wherein, The active component of the hydrogen-type molecular sieve accounts for 2 wt% to 20 wt% of the mass of the honeycomb substrate.

3. The odor-neutralizing catalyst material according to claim 1 or 2, wherein, The active component of the hydrogen-type molecular sieve includes at least one of HZSM-5 molecular sieve and Beta molecular sieve.

4. The odor-neutralizing catalyst material according to any one of claims 1 to 3, wherein, The oxygen vacancy-type active component accounts for 1 wt% to 10 wt% of the mass of the cellular substrate.

5. The odor-neutralizing catalyst material according to any one of claims 1 to 4, wherein, The oxygen vacancy-type active component is a metal oxide containing oxygen vacancies, and the metal oxide includes at least one of manganese oxide, copper oxide, iron oxide, and cerium oxide.

6. The odor-neutralizing catalyst material according to claim 5, wherein, The metal oxide is a mixture of oxides of manganese, copper, and iron.

7. The odor-neutralizing catalyst material according to claim 5 or 6, wherein, The metal oxide is a mixture of manganese oxide and copper oxide.

8. The odor-neutralizing catalyst material according to any one of claims 1 to 7, wherein, The hydrogen-type molecular sieve active component is connected to the honeycomb substrate by an adhesive, and the oxygen vacancy-type active component is distributed in the pores and on the surface of the hydrogen-type molecular sieve active component.

9. The odor-neutralizing catalyst material according to any one of claims 1 to 8, wherein, The honeycomb substrate includes at least one of cordierite ceramic honeycomb, alumina honeycomb, aluminum metal honeycomb, and fiberglass honeycomb.

10. A method for preparing an odor-neutralizing catalyst material as described in any one of claims 1 to 9, comprising the following steps: The honeycomb substrate was sequentially impregnated in hydrogen-type molecular sieve slurry and metal salt solution, and then calcined. Alternatively, hydrogen-type molecular sieves loaded with metal oxides can be first prepared into a slurry and then dip-coated onto the honeycomb substrate.

11. The method according to claim 10, wherein, The components of the hydrogen-type molecular sieve slurry include hydrogen-type molecular sieves, binders, and thickeners.

12. The method according to claim 11, wherein, The adhesive includes at least one of silica sol, alumina sol, bentonite, sodium silicate, and aluminum dihydrogen phosphate.

13. The method according to claim 11 or 12, wherein, The thickener includes at least one of sodium carboxymethyl cellulose, polyvinyl alcohol, xanthan gum, and sodium alginate.

14. The method according to any one of claims 10 to 13, wherein, The metal salt solution contains at least one of manganese, copper, iron, and cerium, and the metal salt contains at least one of nitrate, sulfate, and acetate.

15. The method according to any one of claims 10 to 14, wherein, After impregnating the honeycomb substrate in a hydrogen-type molecular sieve slurry, the honeycomb substrate is first removed, excess slurry is blown off, and then dried and cured to obtain a honeycomb ceramic loaded with molecular sieve.

16. The method according to claim 15, wherein, The drying and curing temperature is 60℃~200℃.

17. The method according to claim 15 or 16, wherein, The drying and curing time is 0.5h to 5h.

18. The method according to any one of claims 10 to 17, wherein, The calcination temperature is 200℃~350℃.

19. The method according to any one of claims 10 to 18, wherein, The calcination time is 0.5h to 5h.

20. A deodorizing module comprising the deodorizing catalyst material according to any one of claims 1 to 9, or comprising the deodorizing catalyst material prepared by the method according to any one of claims 10 to 19.

21. A refrigeration device, comprising the odor-eliminating module as described in claim 16.

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