Composite catalyst, method for preparing the same, and use thereof

Abstract

This application discloses a composite catalyst, its preparation method, and its application. The composite catalyst comprises: a honeycomb support; a powder support on which at least a portion of the surface of the honeycomb support is loaded; and a catalyst loaded on at least a portion of the surface of the honeycomb support and / or the powder support. The catalyst comprises manganese dioxide, iron oxide, copper oxide, and rare earth metal oxides, and the mass ratio of manganese dioxide, iron oxide, copper oxide, and rare earth metal oxides is (38–55):(10–25):(30–40):(1–8). The composite catalyst of this application exhibits superior decomposition and removal effects on trimethylamine and can significantly remove the fishy odor produced during the cooking of seafood. Furthermore, the composite catalyst of this application uses common metal oxides instead of precious metal catalysts, significantly reducing costs.

Description

Technical Field

[0001] This application belongs to the field of odor removal technology, specifically relating to a composite catalyst, its preparation method, and its application. Background Technology

[0002] During the cooking and baking of seafood and other foods using kitchen appliances, many odor molecules with a fishy or pungent smell are produced. Analysis reveals that these molecules are mainly amines and aldehydes. Trimethylamine, with its low odor threshold, is the primary cause of the fishy or pungent odor, making its removal a crucial solution. Current technologies often use precious metals such as phosphorus (Pt) as catalysts to treat trimethylamine. Under the action of the catalyst, trimethylamine molecules are oxidized and decomposed. However, precious metals are expensive and difficult to apply widely. Therefore, how to treat trimethylamine using common catalysts is a current research focus. Summary of the Invention

[0003] This application aims to at least partially address one of the technical problems in related technologies. Therefore, the purpose of this application is to propose a composite catalyst, its preparation method, and its application. The composite catalyst of this application exhibits superior decomposition and removal effects on trimethylamine, and can significantly remove the fishy odor produced during the cooking of seafood and other seafood. Furthermore, the composite catalyst of this application uses common metal oxides instead of precious metal catalysts, significantly reducing costs.

[0004] In one aspect of this application, a composite catalyst is proposed. According to an embodiment of this application, the composite catalyst comprises:

[0005] Cellular carrier;

[0006] A powder carrier on which at least a portion of the surface of the honeycomb carrier is loaded;

[0007] A catalyst, wherein the catalyst is supported on at least a portion of the surface of the honeycomb carrier and / or the powder carrier, the catalyst comprising manganese dioxide, iron oxide, copper oxide and rare earth metal oxide, and the mass ratio of the manganese dioxide, the iron oxide, the copper oxide and the rare earth metal oxide is (38-55):(10-25):(30-40):(1-8).

[0008] According to the composite catalyst of this application embodiment, the composite catalyst adopts a dual-carrier configuration, with a honeycomb carrier as the basic carrier and a powder carrier as the second carrier supporting at least a portion of the surface of the honeycomb carrier. This effectively increases the specific surface area for attaching catalyst particles, thereby significantly improving the catalytic effect per unit volume of catalyst. Furthermore, the catalyst of this application includes manganese dioxide, iron oxide, copper oxide, and rare earth metal oxides. Under the combined action of manganese dioxide, iron oxide, copper oxide, and rare earth metal oxides, the composite catalyst of this application exhibits excellent decomposition and removal effects of trimethylamine, and can significantly remove the fishy odor produced during the cooking of seafood. Moreover, the synergistic effect among manganese dioxide, iron oxide, copper oxide, and rare earth metal oxides is indispensable. Simultaneously, the composite catalyst of this application uses common metal oxides, rather than precious metal catalysts, significantly reducing costs.

[0009] In addition, the composite catalyst according to the above embodiments of this application may also have the following additional technical features:

[0010] In some embodiments of this application, the mass ratio of the cellular carrier, the powder carrier, and the catalyst is 10:(0.1-1.5):(0.1-2).

[0011] In some embodiments of this application, the mass ratio of the cellular carrier, the powder carrier, and the catalyst is 10:(0.3-1.2):(0.5-2).

[0012] In some embodiments of this application, the rare earth metal oxide includes at least one of cerium dioxide and lanthanum oxide.

[0013] In some embodiments of this application, the cellular carrier includes at least one of a cellular ceramic carrier and a cellular metal carrier.

[0014] In some embodiments of this application, the material of the cellular ceramic carrier includes at least one of cordierite, alumina, silicon oxide, and silicon carbide.

[0015] In some embodiments of this application, the powder carrier includes at least one of alumina powder and molecular sieve.

[0016] In some embodiments of this application, the average particle size of the alumina powder is 5 nm to 1000 nm.

[0017] In a second aspect, this application provides a method for preparing the composite catalysts of the above embodiments. According to an embodiment of this application, the method includes:

[0018] A solution containing manganese ions, iron ions, copper ions and rare earth metal ions is mixed with an alkaline solution, reacted to form a precipitate, the solid and liquid are separated, dried, and then calcined for the first time to obtain catalyst powder.

[0019] The powder carrier is dispersed in a first dispersion solution to obtain a first mixture;

[0020] The honeycomb carrier is immersed in the first mixture, removed and dried, and then calcined a second time to obtain the mixed carrier;

[0021] The catalyst powder is dispersed in a second dispersion solution to obtain a second mixture. The mixed support is then immersed in the second mixture, removed, dried, and subjected to a third calcination to obtain the composite catalyst.

[0022] According to the method for preparing composite catalysts according to embodiments of this application, a powder carrier is loaded onto the surface of a honeycomb carrier using an impregnation method. After sintering, the powder carrier is firmly loaded onto the surface of the honeycomb carrier and is not easily detached, further increasing the specific surface area for attaching catalyst particles, thereby significantly improving the catalytic effect per unit volume of catalyst. Simultaneously, this method loads catalyst powder onto the surface of a dual-carrier using an impregnation method, and after sintering, a composite catalyst is formed. After sintering, the catalyst powder is firmly loaded onto the surface of the dual-carrier and is not easily detached. This method results in a large loading capacity of catalyst powder that is not easily detached. Furthermore, the catalyst prepared by the method of this application includes manganese dioxide, iron oxide, copper oxide, and rare earth metal oxides. Under the combined action of manganese dioxide, iron oxide, copper oxide, and rare earth metal oxides, the composite catalyst of this application exhibits excellent decomposition and removal effects of trimethylamine, and can significantly remove the fishy odor produced during the cooking of seafood. Moreover, the composite catalyst of this application uses common metal oxides instead of precious metal catalysts, significantly reducing costs.

[0023] In addition, the method according to the above embodiments of this application may also have the following additional technical features:

[0024] In some embodiments of this application, the alkaline solution is added to the solution containing manganese ions, iron ions, copper ions and rare earth metal ions until the pH of the mixed solution is equal to 7, thereby performing solid-liquid separation.

[0025] In some embodiments of this application, the first dispersion solution and the second dispersion solution are citric acid solutions with a mass fraction of 15% to 25%.

[0026] In some embodiments of this application, the mass ratio of the honeycomb carrier, the powder carrier, and the catalyst powder is 10:(0.2-4):(0.2-4).

[0027] In some embodiments of this application, the temperature of the first calcination is 500℃~800℃, and the time of the first calcination is 1h~6h; and / or, the temperature of the second calcination is 500℃~800℃, and the time of the second calcination is 1h~6h; and / or, the temperature of the third calcination is 500℃~800℃, and the time of the third calcination is 1h~6h.

[0028] In some embodiments of this application, the cellular carrier is immersed in the first mixture for 1 hour to 5 hours; and / or, the mixed carrier is immersed in the second mixture for 1 hour to 5 hours.

[0029] In a third aspect, this application proposes the application of a composite catalyst as described in the above embodiments or prepared by the methods described in the above embodiments in refrigerators, ovens, microwave ovens, and exhaust gas treatment. Placing the composite catalyst of this application in refrigerators, ovens, microwave ovens, or exhaust gas treatment systems exhibits superior decomposition and removal effects of trimethylamine.

[0030] Additional aspects and advantages of this application will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of this application. Attached Figure Description

[0031] The above and / or additional aspects and advantages of this application will become apparent and readily understood from the description of the embodiments taken in conjunction with the following drawings, in which:

[0032] Figure 1 This is a schematic flowchart illustrating the method for preparing composite catalysts according to some embodiments of this application;

[0033] Figure 2 This is a schematic flowchart illustrating a method for preparing composite catalysts according to some embodiments of this application. Detailed Implementation

[0034] The embodiments described below are exemplary and intended to explain the present application, and should not be construed as limiting the present application.

[0035] In one aspect of this application, a composite catalyst is proposed. According to an embodiment of this application, the composite catalyst comprises: a honeycomb support; a powder support on which at least a portion of the surface of the honeycomb support is loaded; and a catalyst on which at least a portion of the surface of the honeycomb support and / or the powder support is loaded. The catalyst comprises manganese dioxide (MnO2), iron oxide (Fe2O3), copper oxide (CuO), and rare earth metal oxides, and the mass ratio of manganese dioxide (MnO2), iron oxide (Fe2O3), copper oxide (CuO), and rare earth metal oxides is (38–55):(10–30):(25–40):(1–8). Thus, the composite catalyst of this application employs a dual-support system, with the honeycomb support as the primary support and the powder support as the secondary support loaded on at least a portion of the surface of the honeycomb support. This effectively increases the specific surface area for attaching catalyst particles, thereby significantly improving the catalytic effect per unit volume of catalyst. Furthermore, the catalyst in this application comprises manganese dioxide, iron oxide, copper oxide, and rare earth metal oxides. Under the combined action of these three compounds, the composite catalyst exhibits superior decomposition and removal effects on trimethylamine, significantly eliminating the fishy odor produced during the cooking of seafood. Moreover, the synergistic effect among manganese dioxide, iron oxide, copper oxide, and rare earth metal oxides is indispensable. Additionally, the composite catalyst in this application uses common metal oxides, rather than precious metal catalysts, significantly reducing costs.

[0036] The principle by which the composite catalyst proposed in this application achieves the above-mentioned beneficial effects will be explained in detail below:

[0037] The composite catalyst of this application employs a dual-carrier approach, using a honeycomb carrier as the primary carrier and a powder carrier as the secondary carrier, supporting at least a portion of the honeycomb carrier's surface. This effectively increases the specific surface area for attaching catalyst particles, increasing the catalyst powder loading on the carrier by more than 10%, thereby significantly improving the catalytic effect per unit volume of catalyst. Furthermore, the catalyst of this application comprises manganese dioxide (MnO2), iron oxide (Fe2O3), copper oxide (CuO), and rare earth metal oxides, with manganese dioxide as the primary component and iron oxide and copper oxide as doped oxides. Due to their large ionic radii, rare earth ions in rare earth metal oxides cause lattice distortion upon introduction, generating more cations and oxygen vacancies, which can further promote the catalytic combustion reaction to decompose and remove trimethylamine. Therefore, under the combined action of manganese dioxide, iron oxide, copper oxide, and rare earth metal oxides, the composite catalyst of this application exhibits superior decomposition and removal effects of trimethylamine, and can significantly remove the fishy odor produced during the cooking of seafood. Moreover, the synergistic effect among manganese dioxide, iron oxide, copper oxide, and rare earth metal oxides is indispensable. Most importantly, the composite catalyst in this application uses ordinary metal oxides instead of precious metal catalysts, which significantly reduces costs.

[0038] Meanwhile, the mass ratio of manganese dioxide, iron oxide, copper oxide and rare earth metal oxide in this application is (38-55):(10-25):(30-40):(1-8). The inventors have found that only by limiting the proportion of each component within the above range can a better effect of decomposing and removing trimethylamine be achieved. If the content of any component is too high or too low, the catalytic effect of this application cannot be achieved.

[0039] According to some specific embodiments of this application, the mass ratio of the honeycomb carrier, the powder carrier, and the catalyst is 10:(0.1-1.5):(0.1-2). Thus, by limiting the mass ratio of the honeycomb carrier, the powder carrier, and the catalyst to the above range, the specific surface area for attaching catalyst particles can be further increased, and the loading of catalyst powder on the carrier can be further increased, thereby further improving the catalytic effect per unit volume of catalyst.

[0040] According to some specific embodiments of this application, the mass ratio of the honeycomb carrier, the powder carrier, and the catalyst is 10:(0.3-1.2):(0.5-2). By limiting the mass ratio of the honeycomb carrier, the powder carrier, and the catalyst to the above range, the specific surface area for attaching catalyst particles can be further increased, and the loading of catalyst powder on the carrier can be further increased, thereby further improving the catalytic effect of catalyst per unit volume.

[0041] In the embodiments of this application, the specific types of rare earth metal oxides are not particularly limited, and those skilled in the art can select them according to actual needs. As some preferred embodiments, the rare earth metal oxides include at least one of cerium dioxide (CeO2) and lanthanum oxide. Due to their large ionic radii, the rare earth ions in the above-mentioned rare earth metal oxides can cause lattice distortion after being introduced, generating more cations and oxygen vacancies, which can further promote the catalytic combustion reaction to decompose and remove trimethylamine. Cerium dioxide (CeO2) is preferred.

[0042] In the embodiments of this application, the specific type of the cellular carrier is not particularly limited. Those skilled in the art can select according to actual needs. As some preferred embodiments, the cellular carrier includes at least one of the cellular ceramic carrier and the cellular metal carrier, with the cellular ceramic carrier being preferred.

[0043] In the embodiments of this application, the specific type of material of the above-mentioned cellular ceramic carrier is not particularly limited. Those skilled in the art can choose according to actual needs. As some preferred embodiments, the material of the cellular ceramic carrier includes at least one of cordierite, alumina, silicon oxide, and silicon carbide, with cordierite being preferred.

[0044] In the embodiments of this application, the specific type of powder carrier is not particularly limited. Those skilled in the art can select according to actual needs. As some preferred embodiments, the powder carrier includes at least one of alumina powder and molecular sieve, preferably nano-sized alumina powder.

[0045] According to some specific embodiments of this application, the average particle size of the alumina powder is 5nm to 1000nm, for example, it can be 5nm, 100nm, 200nm, 300nm, 400nm, 500nm, 600nm, 700nm, 800nm, 900nm, 1000nm, etc. This further increases the specific surface area of ​​the alumina powder, that is, increases the specific surface area for attaching catalyst particles, and further increases the loading of catalyst powder on the carrier.

[0046] In a second aspect, this application provides a method for preparing the composite catalysts of the above embodiments. According to embodiments of this application, refer to the appendix... Figure 1 and attached Figure 2 The method includes:

[0047] S100: A solution containing manganese ions, iron ions, copper ions and rare earth metal ions is mixed with an alkaline solution, reacted to form a precipitate, the solid and liquid are separated, dried, and then calcined for the first time to obtain catalyst powder.

[0048] In this step, an alkaline solution (e.g., sodium hydroxide) can be added to a solution containing manganese ions, iron ions, copper ions, and rare earth metal ions. The manganese ions, iron ions, copper ions, and rare earth metal ions react with hydroxide ions (OH-) in the alkaline solution, respectively. - The reaction proceeds to form a precipitate until the pH of the mixed solution reaches 7. At this point, manganese, iron, copper, and rare earth metal ions have reacted completely. Solid-liquid separation is then performed to separate the precipitate. The precipitate is washed, dried, and then subjected to a first calcination, which decomposes the precipitate to obtain catalyst powder, namely manganese dioxide (MnO2), iron oxide (Fe2O3), copper oxide (CuO), and rare earth metal oxide powder. This co-precipitation method achieves co-doping of the components, further improving the catalyst's ability to catalyze the removal of trimethylamine.

[0049] According to some specific embodiments of this application, the drying temperature can be 80℃ to 200℃, for example, 80℃, 100℃, 120℃, 140℃, 160℃, 180℃, 200℃, etc.

[0050] According to some specific embodiments of this application, the temperature of the first calcination is 500℃~800℃ (e.g., 500℃, 550℃, 600℃, 650℃, 700℃, 750℃, 800℃, etc.), and the time of the first calcination is 1h~6h (e.g., 1h, 2h, 3h, 4h, 5h, 6h, etc.), thereby ensuring that the precipitate is effectively decomposed to obtain catalyst powder, namely manganese dioxide (MnO2), iron oxide (Fe2O3), copper oxide (CuO) and rare earth metal oxide powder.

[0051] In the embodiments of this application, the solutions containing manganese ions, iron ions, copper ions and rare earth metal ions are not particularly limited. For example, they can be nitrate solutions containing manganese ions, iron ions, copper ions and rare earth metal ions, or sulfate solutions containing manganese ions, iron ions, copper ions and rare earth metal ions.

[0052] In the embodiments of this application, the mass ratio of the nitrate or sulfate containing manganese ions, the nitrate or sulfate containing iron ions, the nitrate or sulfate containing copper ions, and the nitrate or sulfate containing rare earth metal ions is not particularly limited, as long as the mass ratio of manganese dioxide, iron oxide, copper oxide, and rare earth metal oxide in the catalyst powder formed by calcination is in the range of (38-55):(10-25):(30-40):(1-8). The inventors have found that only by limiting the proportion of each component within the above range can a better effect of decomposing and removing trimethylamine be achieved. If the content of any component is too high or too low, the catalytic effect of this application cannot be achieved.

[0053] S200: Disperse the powder carrier in the first dispersion solution to obtain the first mixture;

[0054] In the embodiments of this application, the specific type of the first dispersion solution is not particularly limited. As some preferred embodiments, the first dispersion solution can be a citric acid solution with a mass fraction of 15% to 25%, such as a citric acid solution with a mass fraction of 15%, 18%, 20%, 22%, or 25%, which has a superior dispersion effect.

[0055] S300: The honeycomb carrier is immersed in the first mixture, taken out and dried, and then calcined a second time to obtain the mixed carrier;

[0056] In this step, the honeycomb carrier is immersed in the first mixture so that the powder carrier in the first mixture is loaded onto the surface of the honeycomb carrier. After drying, it is calcined a second time to obtain the mixed carrier. This application uses an immersion method to load the powder carrier onto the surface of the honeycomb carrier. After sintering, the powder carrier can be firmly loaded onto the surface of the honeycomb carrier and is not easy to fall off, which further increases the specific surface area for attaching catalyst particles, thereby significantly improving the catalytic effect per unit volume of catalyst.

[0057] According to some specific embodiments of this application, the temperature of the second calcination is 500℃~800℃ (e.g., 500℃, 550℃, 600℃, 650℃, 700℃, 750℃, 800℃, etc.), and the time of the second calcination is 1h~6h (e.g., 1h, 2h, 3h, 4h, 5h, 6h, etc.), which can further ensure that the sintered powder is firmly loaded on the surface of the honeycomb carrier and is not easy to fall off.

[0058] According to some specific embodiments of this application, the honeycomb carrier is immersed in the first mixture for 1 hour to 5 hours, for example, 1 hour, 2 hours, 3 hours, 4 hours, 5 hours, etc., thereby ensuring that the powder carrier is fully loaded on the surface of the honeycomb carrier.

[0059] S400: The catalyst powder is dispersed in the second dispersion solution to obtain the second mixture. The mixed support is immersed in the second mixture, taken out and dried, and then calcined for the third time to obtain the composite catalyst.

[0060] In this step, the catalyst powder is dispersed in a second dispersion solution to obtain a second mixture. The mixed support is then immersed in the second mixture so that the catalyst powder is loaded onto at least a portion of the surface of the honeycomb support and / or the powder support. After loading, the mixture is removed, dried, and subjected to a third calcination to obtain the composite catalyst. The method of this application loads catalyst powder onto the surface of a dual support via impregnation, and then sintersects to form a composite catalyst. After sintering, the catalyst powder is firmly loaded onto the surface of the dual support and is not easily detached. This method results in a large loading capacity of the catalyst powder and prevents it from detaching.

[0061] According to some specific embodiments of this application, the temperature of the third calcination is 500℃~800℃ (e.g., 500℃, 550℃, 600℃, 650℃, 700℃, 750℃, 800℃, etc.), and the time of the third calcination is 1h~6h (e.g., 1h, 2h, 3h, 4h, 5h, 6h, etc.), which can further ensure that the sintered catalyst powder is firmly loaded on the surface of the dual carrier and is not easy to fall off.

[0062] According to some specific embodiments of this application, the mixed carrier is immersed in the second mixture for 1 hour to 5 hours, for example, 1 hour, 2 hours, 3 hours, 4 hours, 5 hours, etc., thereby ensuring that the catalyst powder is fully loaded on the surface of the dual carrier.

[0063] According to some specific embodiments of this application, the mass ratio of the honeycomb carrier, the powder carrier, and the catalyst powder is 10:(0.2-4):(0.2-4). Thus, by limiting the mass ratio of the honeycomb carrier, the powder carrier, and the catalyst powder in the preparation process to the above range, the specific surface area for attaching catalyst particles can be further increased, and the loading of catalyst powder on the carrier can be further increased, thereby further improving the catalytic effect of catalyst per unit volume.

[0064] According to the method for preparing composite catalysts according to embodiments of this application, a powder carrier is loaded onto the surface of a honeycomb carrier using an impregnation method. After sintering, the powder carrier is firmly loaded onto the surface of the honeycomb carrier and is not easily detached, further increasing the specific surface area for attaching catalyst particles, thereby significantly improving the catalytic effect per unit volume of catalyst. Simultaneously, this method loads catalyst powder onto the surface of a dual-carrier using an impregnation method, and after sintering, a composite catalyst is formed. After sintering, the catalyst powder is firmly loaded onto the surface of the dual-carrier and is not easily detached. This method results in a large loading capacity of catalyst powder that is not easily detached.

[0065] Furthermore, the catalyst prepared by the method of this application includes manganese dioxide, iron oxide, copper oxide, and rare earth metal oxides. Under the combined action of manganese dioxide, iron oxide, copper oxide, and rare earth metal oxides, the composite catalyst of this application exhibits superior decomposition and removal effects of trimethylamine, and can significantly remove the fishy odor produced during the cooking of seafood and other seafood. At the same time, the composite catalyst of this application uses common metal oxides, rather than precious metal catalysts, which significantly reduces costs.

[0066] In a third aspect, this application proposes the application of a composite catalyst as described in the above embodiments or prepared by the methods described in the above embodiments in refrigerators, ovens, microwave ovens, and exhaust gas treatment. Placing the composite catalyst of this application in refrigerators, ovens, microwave ovens, or exhaust gas treatment systems exhibits superior decomposition and removal effects of trimethylamine. In particular, it can significantly remove the fishy odor produced by kitchen appliances during the cooking of seafood and other foods.

[0067] The embodiments of this application are described in detail below. It should be noted that the embodiments described below are exemplary and are only used to explain this application, and should not be construed as limiting this application. In addition, unless otherwise specified, all reagents used in the following embodiments are commercially available or can be synthesized according to the methods described herein or known methods. For reaction conditions not listed, they are also readily available to those skilled in the art.

[0068] Example 1

[0069] This embodiment provides a composite catalyst, the preparation method of which is as follows:

[0070] (1) Nitrates Mn(NO3)2, Fe(NO3)3, Cu(NO3)2, and Ce(NO3)3 were weighed according to the following proportions, with a mass ratio of 41.7:22.6:32.3:3.4. The nitrates were dissolved in 100g of water, stirred until dissolved, and sodium hydroxide solution was added until the pH of the mixed solution reached 7. The solution was filtered and washed, dried at 120℃ to remove the precipitate, and then calcined at 580℃ for 5h to obtain catalyst powder. EDS analysis showed that the mass ratio of MnO2, Fe2O3, CuO, and CeO2 in the prepared catalyst powder was approximately 46:17:35:4.

[0071] (2) Disperse 10g of alumina powder with an average particle size of about 100nm in 200g of citric acid solution, which is an aqueous solution with a mass fraction of 20%.

[0072] (3) 100g of cordierite honeycomb ceramic was immersed in the above alumina / citric acid solution for 3h, then dried at 120℃ and calcined at 700℃ for 3h to obtain a mixed carrier.

[0073] (4) Disperse 40g of the above catalyst powder in a 20% citric acid solution, immerse it in the mixed carrier for 3h, take it out and dry it at 120℃, and calcine it at 600℃ for 3h to obtain the honeycomb ceramic catalyst.

[0074] According to EDS analysis, the mass ratio of honeycomb ceramic, alumina and catalyst in the prepared honeycomb ceramic catalyst is approximately 10:0.8:2.

[0075] Example 2

[0076] This embodiment provides a composite catalyst, the preparation method of which is as follows:

[0077] (1) Nitrates Mn(NO3)2, Fe(NO3)3, Cu(NO3)2, and Ce(NO3)3 were weighed according to the following proportions, with a mass ratio of 38.3:23.9:34.3:3.5. The nitrates were dissolved in 100g of water, stirred until dissolved, and sodium hydroxide solution was added until the pH of the mixed solution reached 7. The solution was filtered and washed, dried at 80℃ to remove the precipitate, and then calcined at 800℃ for 1h to obtain catalyst powder. EDS analysis showed that the mass ratio of MnO2, Fe2O3, CuO, and CeO2 in the prepared catalyst powder was approximately 40:17:35:4.

[0078] (2) Disperse 10g of alumina powder with an average particle size of about 300nm in 200g of citric acid solution, which is an aqueous solution with a mass fraction of 15%.

[0079] (3) 100g of cordierite honeycomb ceramic was immersed in the above alumina / citric acid solution for 5h, then dried at 200℃ and calcined at 500℃ for 6h to obtain a mixed carrier.

[0080] (4) Disperse 40g of the above catalyst powder in a 15% citric acid solution, immerse it in a mixed carrier for 5h, take it out and dry it at 120℃, and calcine it at 700℃ for 3h to obtain a honeycomb ceramic catalyst.

[0081] According to EDS analysis, the mass ratio of honeycomb ceramic, alumina and catalyst in the prepared honeycomb ceramic catalyst is approximately 10:1.2:2.

[0082] Example 3

[0083] This embodiment provides a composite catalyst, the preparation method of which is as follows:

[0084] (1) Nitrates Mn(NO3)2, Fe(NO3)3, Cu(NO3)2, and Ce(NO3)3 were weighed according to the following proportions, with a mass ratio of 45.2:21.2:30.5:3.1. The nitrates were dissolved in 100g of water by stirring. Sodium hydroxide solution was added until the pH of the mixed solution reached 7. The solution was filtered and washed, and the precipitate was dried at 150℃. Then, the precipitate was calcined at 700℃ for 3 hours to obtain catalyst powder. EDS analysis showed that the mass ratio of MnO2, Fe2O3, CuO, and CeO2 in the prepared catalyst powder was approximately 53:17:35:4.

[0085] (2) Disperse 10g of alumina powder with an average particle size of about 500nm in 200g of citric acid solution, which is an aqueous solution with a mass fraction of 25%.

[0086] (3) 100g of cordierite honeycomb ceramic was immersed in the above alumina / citric acid solution for 1 hour, then dried at 150°C and calcined at 600°C for 5 hours to obtain a mixed carrier.

[0087] (4) Disperse 40g of the above catalyst powder in a 25% citric acid solution, immerse it in the mixed carrier for 1h, take it out and dry it at 150℃, and calcine it at 600℃ for 3h to obtain the honeycomb ceramic catalyst.

[0088] According to EDS analysis, the mass ratio of honeycomb ceramic, alumina and catalyst in the prepared honeycomb ceramic catalyst is approximately 10:0.7:2.

[0089] Example 4

[0090] This embodiment provides a composite catalyst, the preparation method of which is basically the same as that of Example 1, the only difference being:

[0091] (1) Nitrates Mn(NO3)2, Fe(NO3)3, Cu(NO3)2, and Ce(NO3)3 were weighed according to the following proportions, with a mass ratio of 41.7:22.6:32.4:3.3. The nitrates were dissolved in 100g of water by stirring. Sodium hydroxide solution was added until the pH of the mixed solution reached 7. The solution was filtered and washed, and the precipitate was dried at 120℃. Then, the precipitate was calcined at 580℃ for 3 hours to obtain catalyst powder. EDS analysis showed that the mass ratio of MnO2, Fe2O3, CuO, and CeO2 in the prepared catalyst powder was approximately 46:10:40:4.

[0092] Example 5

[0093] This embodiment provides a composite catalyst, the preparation method of which is basically the same as that of Example 1, the only difference being:

[0094] (1) Nitrates Mn(NO3)2, Fe(NO3)3, Cu(NO3)2, and Ce(NO3)3 were weighed according to the following proportions, with a mass ratio of 39.3:31.3:26.2:3.2. The nitrates were dissolved in 100g of water by stirring. Sodium hydroxide solution was added until the pH of the mixed solution reached 7. The solution was filtered and washed, and the precipitate was dried at 120℃. Then, the precipitate was calcined at 580℃ for 3 hours to obtain catalyst powder. EDS analysis showed that the mass ratio of MnO2, Fe2O3, CuO, and CeO2 in the prepared catalyst powder was approximately 46:25:30:4.

[0095] Example 6

[0096] This embodiment provides a composite catalyst, the preparation method of which is basically the same as that of Example 1, the only difference being:

[0097] (1) Nitrates Mn(NO3)2, Fe(NO3)3, Cu(NO3)2, and Ce(NO3)3 were weighed according to the following ratio: Mn(NO3)2, Fe(NO3)3, Cu(NO3)2, and Ce(NO3)3 in a mass ratio of 42.4:22.9:33:1.7. The precipitate was dissolved in 100g of water by stirring. Sodium hydroxide solution was added until the pH of the mixed solution reached 7. The solution was filtered and washed, dried at 120℃, and then calcined at 580℃ for 3 hours to obtain catalyst powder. EDS analysis showed that the mass ratio of MnO2, Fe2O3, CuO, and CeO2 in the prepared catalyst powder was approximately 46:17:35:2.

[0098] Example 7

[0099] This embodiment provides a composite catalyst, the preparation method of which is basically the same as that of Example 1, the only difference being:

[0100] (1) Nitrates Mn(NO3)2, Fe(NO3)3, Cu(NO3)2, and Ce(NO3)3 were weighed according to the following proportions, with a mass ratio of 40.4:21.8:31.3:6.5. The nitrates were dissolved in 100g of water by stirring. Sodium hydroxide solution was added until the pH of the mixed solution reached 7. The solution was filtered and washed, and the precipitate was dried at 120℃. Then, the precipitate was calcined at 580℃ for 3 hours to obtain catalyst powder. EDS analysis showed that the mass ratio of MnO2, Fe2O3, CuO, and CeO2 in the prepared catalyst powder was approximately 46:17:35:8.

[0101] Example 8

[0102] This embodiment provides a composite catalyst, the preparation method of which is basically the same as that of Example 1, the only difference being:

[0103] (2) Disperse 2g of alumina powder with an average particle size of about 100nm in 200g of citric acid solution, which is an aqueous solution with a mass fraction of 20%.

[0104] (3) 100g of cordierite honeycomb ceramic was immersed in the above alumina / citric acid solution for 2.5h, then dried at 120℃ and calcined at 700℃ for 3h to obtain a mixed carrier.

[0105] (4) Disperse 2g of the above catalyst powder in a 20% citric acid solution, immerse it in the mixed carrier for 2.5h, take it out and dry it at 120℃, and calcine it at 600℃ for 3h to obtain the honeycomb ceramic catalyst.

[0106] According to EDS analysis, the mass ratio of honeycomb ceramic, alumina and catalyst in the prepared honeycomb ceramic catalyst is approximately 10:0.1:0.1.

[0107] Example 9

[0108] This embodiment provides a composite catalyst, the preparation method of which is basically the same as that of Example 1, the only difference being:

[0109] (2) Disperse 6g of alumina powder with an average particle size of about 100nm in 200g of citric acid solution, which is an aqueous solution with a mass fraction of 20%.

[0110] (3) 100g of cordierite honeycomb ceramic was immersed in the above alumina / citric acid solution for 2.5h, then dried at 120℃ and calcined at 700℃ for 3h to obtain a mixed carrier.

[0111] (4) Disperse 10g of the above catalyst powder in a 20% citric acid solution, immerse it in the mixed carrier for 2.5h, take it out and dry it at 120℃, and calcine it at 600℃ for 3h to obtain the honeycomb ceramic catalyst.

[0112] According to EDS analysis, the mass ratio of honeycomb ceramic, alumina and catalyst in the prepared honeycomb ceramic catalyst is approximately 10:0.3:0.5.

[0113] Example 10

[0114] This embodiment provides a composite catalyst, the preparation method of which is basically the same as that of Example 1, the only difference being:

[0115] (2) Disperse 10g of alumina powder with an average particle size of about 100nm in 200g of citric acid solution, which is an aqueous solution with a mass fraction of 20%.

[0116] (3) 100g of cordierite honeycomb ceramic was immersed in the above alumina / citric acid solution for 2.5h, then dried at 120℃ and calcined at 700℃ for 3h to obtain a mixed carrier.

[0117] (4) Disperse 20g of the above catalyst powder in a 20% citric acid solution, immerse it in the mixed carrier for 2.5h, take it out and dry it at 120℃, and calcine it at 600℃ for 3h to obtain the honeycomb ceramic catalyst.

[0118] According to EDS analysis, the mass ratio of honeycomb ceramic, alumina and catalyst in the prepared honeycomb ceramic catalyst is approximately 10:0.6:1.

[0119] Example 11

[0120] This embodiment provides a composite catalyst, the preparation method of which is basically the same as that of Example 1, the only difference being:

[0121] (2) 24g of alumina powder with an average particle size of about 100nm was dispersed in 200g of citric acid solution, which was an aqueous solution with a mass fraction of 20%.

[0122] (3) 100g of cordierite honeycomb ceramic was immersed in the above alumina / citric acid solution for 2.5h, then dried at 120℃ and calcined at 700℃ for 3h to obtain a mixed carrier.

[0123] (4) Disperse 40g of the above catalyst powder in a 20% citric acid solution, immerse it in a mixed carrier for 2.5h, take it out and dry it at 120℃, and calcine it at 600℃ for 3h to obtain a honeycomb ceramic catalyst.

[0124] According to EDS analysis, the mass ratio of honeycomb ceramic, alumina and catalyst in the prepared honeycomb ceramic catalyst is approximately 10:1.2:2.

[0125] Example 12

[0126] This embodiment provides a composite catalyst, the preparation method of which is basically the same as that of Example 1, the only difference being:

[0127] (2) Disperse 30g of alumina powder with an average particle size of about 100nm in 200g of citric acid solution, which is an aqueous solution with a mass fraction of 20%.

[0128] (3) 100g of cordierite honeycomb ceramic was immersed in the above alumina / citric acid solution for 2.5h, then dried at 120℃ and calcined at 700℃ for 3h to obtain a mixed carrier.

[0129] (4) Disperse 40g of the above catalyst powder in a 20% citric acid solution, immerse it in a mixed carrier for 2.5h, take it out and dry it at 120℃, and calcine it at 600℃ for 3h to obtain a honeycomb ceramic catalyst.

[0130] According to EDS analysis, the mass ratio of honeycomb ceramic, alumina and catalyst in the prepared honeycomb ceramic catalyst is approximately 10:1.5:2.

[0131] Comparative Example 1

[0132] This comparative example provides a composite catalyst, the preparation method of which is basically the same as that of Example 1, the only difference being:

[0133] (1) Nitrates Mn(NO3)2, Fe(NO3)3, Cu(NO3)2, and Ce(NO3)3 were weighed according to the following proportions, with a mass ratio of 61.4:11:24.1:3.5. The nitrates were dissolved in 100g of water, stirred until dissolved, and sodium hydroxide solution was added until the pH of the mixed solution reached 7. The solution was filtered and washed, dried at 120℃ to remove the precipitate, and then calcined at 580℃ for 5h to obtain catalyst powder. EDS analysis showed that the mass ratio of MnO2, Fe2O3, CuO, and CeO2 in the prepared catalyst powder was approximately 65:8:25:4.

[0134] Comparative Example 2

[0135] This comparative example provides a composite catalyst, the preparation method of which is basically the same as that of Example 1, the only difference being:

[0136] (1) Nitrates Mn(NO3)2, Fe(NO3)3, Cu(NO3)2, and Ce(NO3)3 were weighed according to the following proportions, with a mass ratio of 25.3:34.3:37.2:3.2. The nitrates were dissolved in 100g of water by stirring. Sodium hydroxide solution was added until the pH of the mixed solution reached 7. The solution was filtered and washed, and the precipitate was dried at 120℃. Then, the precipitate was calcined at 580℃ for 5 hours to obtain catalyst powder. EDS analysis showed that the mass ratio of MnO2, Fe2O3, CuO, and CeO2 in the prepared catalyst powder was approximately 29:27:42:4.

[0137] Comparative Example 3

[0138] This comparative example provides a composite catalyst, the preparation method of which is basically the same as that of Example 1, the only difference being:

[0139] (1) Nitrates Mn(NO3)2, Fe(NO3)3, Cu(NO3)2, and Ce(NO3)3 were weighed according to the following proportions, with a mass ratio of 44.8:22.5:32.3:0.4. The nitrates were dissolved in 100g of water, stirred until dissolved, and sodium hydroxide solution was added until the pH of the mixed solution reached 7. The solution was filtered and washed, dried at 120℃ to remove the precipitate, and then calcined at 580℃ for 5h to obtain catalyst powder. EDS analysis showed that the mass ratio of MnO2, Fe2O3, CuO, and CeO2 in the prepared catalyst powder was approximately 49.5:17:35:0.5.

[0140] Comparative Example 4

[0141] This comparative example provides a composite catalyst, the preparation method of which is basically the same as that of Example 1, the only difference being:

[0142] (1) Nitrates Mn(NO3)2, Fe(NO3)3, Cu(NO3)2, and Ce(NO3)3 were weighed according to the following proportions, with a mass ratio of 36.4:22.7:32.5:8.4. The nitrates were dissolved in 100g of water by stirring. Sodium hydroxide solution was added until the pH of the mixed solution reached 7. The solution was filtered and washed, and the precipitate was dried at 120℃. Then, the precipitate was calcined at 580℃ for 5 hours to obtain catalyst powder. EDS analysis showed that the mass ratio of MnO2, Fe2O3, CuO, and CeO2 in the prepared catalyst powder was approximately 40:17:35:10.

[0143] The removal capacity of the composite catalysts prepared in Examples 1-12 and Comparative Examples 1-4 for trimethylamine was tested, and the specific test methods are as follows:

[0144] Add 500 μL of trimethylamine to a 1 cubic meter cavity, turn on the fan installed in the cavity for 10 minutes to make the trimethylamine evenly distributed in the cavity, and heat the honeycomb ceramic with a heating platform for 30 minutes. Use a trimethylamine detection tube to test the trimethylamine concentration before and after heating. The amount of trimethylamine removed = (trimethylamine concentration before heating - trimethylamine concentration before heating) / trimethylamine concentration before heating * 100%.

[0145] The test results are shown in Table 1.

[0146] Table 1

[0147]

[0148]

[0149] As can be seen from Table 1, the composite catalysts prepared in Examples 1-12 all exhibit excellent removal effects on trimethylamine. This demonstrates that, under the combined action of manganese dioxide, iron oxide, copper oxide, and rare earth metal oxides, the composite catalysts of this application demonstrate superior decomposition and removal effects on trimethylamine, and can significantly remove the fishy odor produced during the cooking of seafood and other seafood.

[0150] As can be seen from Table 1, compared with Comparative Examples 1-4, the composite catalyst prepared in Example 1 has a better removal effect on trimethylamine. It can be seen that only by limiting the ratio of manganese dioxide, iron oxide, copper oxide and rare earth metal oxide within a certain range, that is, limiting the mass ratio of manganese dioxide, iron oxide, copper oxide and rare earth metal oxide within the range of (38-55):(10-25):(30-40):(1-8), can a better decomposition and removal effect of trimethylamine be achieved. If the content of any component is too high or too low, the catalytic effect of this application cannot be achieved.

[0151] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "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. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0152] Although embodiments of this application have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting this application. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of this application.

Claims

1. A composite catalyst, characterized in that, include: Cellular carrier; A powder carrier on which at least a portion of the surface of the honeycomb carrier is loaded; A catalyst, wherein the catalyst is supported on at least a portion of the surface of the honeycomb carrier and / or the powder carrier, the catalyst comprising manganese dioxide, iron oxide, copper oxide and rare earth metal oxide, and the mass ratio of the manganese dioxide, the iron oxide, the copper oxide and the rare earth metal oxide is (38-55):(10-25):(30-40):(1-8).

2. The composite catalyst according to claim 1, characterized in that, The mass ratio of the honeycomb carrier, the powder carrier, and the catalyst is 10:(0.1-1.5):(0.1-2).

3. The composite catalyst according to claim 1, characterized in that, The mass ratio of the honeycomb carrier, the powder carrier, and the catalyst is 10:(0.3-1.2):(0.5-2).

4. The composite catalyst according to claim 1, characterized in that, The rare earth metal oxide includes at least one of cerium dioxide and lanthanum oxide.

5. The composite catalyst according to any one of claims 1 to 4, characterized in that, The cellular carrier includes at least one of a cellular ceramic carrier and a cellular metal carrier.

6. The composite catalyst according to claim 5, characterized in that, The material of the cellular ceramic carrier includes at least one of cordierite, alumina, silicon oxide, and silicon carbide.

7. The composite catalyst according to any one of claims 1 to 4, characterized in that, The powder carrier includes at least one of alumina powder and molecular sieve.

8. The composite catalyst according to claim 7, characterized in that, The alumina powder has an average particle size of 5 nm to 1000 nm.

9. A method for preparing the composite catalyst according to any one of claims 1 to 8, characterized in that, include: A solution containing manganese ions, iron ions, copper ions and rare earth metal ions is mixed with an alkaline solution, reacted to form a precipitate, the solid and liquid are separated, dried, and then calcined for the first time to obtain catalyst powder. The powder carrier is dispersed in a first dispersion solution to obtain a first mixture; The honeycomb carrier is immersed in the first mixture, removed and dried, and then calcined a second time to obtain the mixed carrier; The catalyst powder is dispersed in a second dispersion solution to obtain a second mixture. The mixed support is then immersed in the second mixture, removed, dried, and subjected to a third calcination to obtain the composite catalyst.

10. The method according to claim 9, characterized in that, The alkaline solution is added to the solution containing manganese ions, iron ions, copper ions and rare earth metal ions until the pH of the mixed solution is equal to 7, thereby performing solid-liquid separation.

11. The method according to claim 9, characterized in that, The first dispersion solution and the second dispersion solution are citric acid solutions with a mass fraction of 15% to 25%.

12. The method according to claim 9, characterized in that, The mass ratio of the honeycomb carrier, the powder carrier, and the catalyst powder is 10:(0.2-4):(0.2-4).

13. The method according to claim 9, characterized in that, The temperature of the first calcination is 500℃~800℃, and the time of the first calcination is 1h~6h; And / or, the temperature of the second calcination is 500℃~800℃, and the time of the second calcination is 1h~6h; And / or, the temperature of the third calcination is 500℃~800℃, and the time of the third calcination is 1h~6h.

14. The method according to claim 9, characterized in that, The honeycomb carrier is immersed in the first mixture for 1 to 5 hours; And / or, immerse the mixed carrier in the second mixture for 1 to 5 hours.

15. The application of a composite catalyst as described in any one of claims 1 to 8 or a composite catalyst prepared by the method described in any one of claims 9 to 14 in refrigerators, ovens, microwave ovens, and exhaust gas treatment.

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