Cerium-manganese binary metal oxide catalyst as well as preparation method and application thereof

Abstract

The invention relates to the technical field of catalysts, in particular to a cerium-manganese binary metal oxide catalyst and a preparation method and application thereof. The chemical composition of the cerium-manganese binary metal oxide catalyst is CeMnaOx, the range of a is 1-20, and the range of x is 4-42; the specific surface area of the cerium-manganese binary metal oxide catalyst is not less than 100m < 2 > / g. The cerium-manganese binary metal oxide catalyst is synthesized in one step through a simple oxidation-reduction reaction, the preparation cost is low, the prepared cerium-manganese binary metal oxide catalyst has the characteristics of high specific surface area and high catalytic activity, and the corresponding reaction temperature is lower than 250 DEG C when the conversion efficiency of toluene reaches 90%.

Description

Technical Field

[0001] The invention relates to the technical field of catalysts, and in particular to a cerium-manganese binary metal oxide catalyst and a preparation method and application thereof. Background Art

[0002] Volatile organic compounds (VOCs) are a series of carbon-based compounds that participate in atmospheric photochemical reactions. They have a wide range of sources and types, and pose a major threat to human health and the ecological environment. Among them, benzene series compounds will cause greater harm to the human body due to their own "three-cause" effects (carcinogenicity, teratogenicity, and mutagenicity). Therefore, it is crucial to find a suitable strategy to reduce VOCs emissions. At present, VOCs treatment technologies are mainly divided into two categories: one is control technology, including adsorption, absorption, condensation, and membrane separation; the other is destructive technology, including direct combustion, catalytic degradation, biodegradation, and plasma technology. Among them, the catalytic degradation method can completely convert VOCs into carbon dioxide and water, and has the advantages of high efficiency, low energy consumption, and no secondary pollution. Therefore, the selection of a suitable catalyst is of great significance for further improving the efficiency of VOCs degradation. At present, the commonly used VOCs catalysts are mainly divided into two types: one is the precious metal catalyst, which has high catalytic efficiency but has the disadvantages of high cost and easy poisoning; the other is the transition metal oxide catalyst, which, although the catalytic effect is not as good as the precious metal catalyst, has low cost and good stability, which is conducive to commercial application. Among them, manganese oxide has rich valence states, diverse crystal forms, and variable morphologies, and has excellent VOCs degradation performance. At the same time, cerium oxide has excellent oxygen storage capacity and can produce more oxygen vacancies, which is beneficial to improve the catalytic degradation performance of VOCs. Therefore, the composite of manganese oxide and cerium oxide has a positive effect on the catalytic degradation of VOCs. At the same time, different proportions, different preparation methods, different raw materials, etc. will affect the catalytic performance of the catalyst.

[0003] At present, the methods for preparing cerium manganese oxide mainly include co-precipitation method, hydrothermal method and sol-gel method. These preparation methods have the problems of being too complicated and costly, which are not conducive to industrial production. For example, the hydrothermal method and sol-gel method require the use of high-temperature and high-pressure equipment, which have disadvantages such as high equipment cost and high operating costs, and also require a lot of time; and the co-precipitation method, as reported in patent CN108435160A, still requires roasting to obtain the product. At the same time, the catalytic effect of the currently prepared cerium manganese oxide on toluene is not good. For example, the reaction temperature corresponding to the conversion efficiency of the prepared cerium manganese oxide on toluene reaches 90% as reported in patent CN113198459A is 306°C, that is, T 90 =306℃.

[0004] Therefore, it is very necessary to develop a cerium-manganese binary metal oxide catalyst that is easy to prepare and has a higher catalytic effect on toluene. Summary of the invention

[0005] The present invention aims to solve at least one of the technical problems existing in the above-mentioned prior art.

[0006] To this end, one of the purposes of the present invention is to provide a cerium-manganese binary metal oxide catalyst, which has a conversion efficiency of 90% for toluene at a corresponding reaction temperature of less than 250° C. and is synthesized in one step through a simple redox reaction.

[0007] The second object of the present invention is to provide a method for preparing the above-mentioned cerium-manganese binary metal oxide catalyst.

[0008] The third object of the present invention is to propose an application of the above-mentioned cerium-manganese binary metal oxide catalyst in the catalytic degradation of volatile organic compounds.

[0009] A fourth object of the present invention is to provide a household appliance containing the above-mentioned cerium-manganese binary metal oxide catalyst.

[0010] According to the cerium-manganese binary metal oxide catalyst of the first embodiment of the present invention, the chemical composition of the cerium-manganese binary metal oxide catalyst is as follows: CeMn a O x , wherein a ranges from 1 to 20, and x ranges from 4 to 42; the specific surface area of ​​the cerium-manganese binary metal oxide catalyst is ≥100m 2 / g.

[0011] The cerium-manganese binary metal oxide catalyst according to the embodiment of the present invention has at least the following beneficial effects: the cerium-manganese binary metal oxide catalyst of the present invention has the characteristics of high specific surface area and high catalytic activity, and exhibits excellent catalytic degradation performance for toluene.

[0012] According to some embodiments of the present invention, the pore size of the cerium-manganese binary metal oxide catalyst is 2-50 nm.

[0013] According to some embodiments of the present invention, the specific surface area of ​​the cerium-manganese binary metal oxide catalyst is 100-300m 2 / g.

[0014] According to some embodiments of the present invention, the specific surface area of ​​the cerium-manganese binary metal oxide catalyst is 100-150m 2 / g.

[0015] According to some embodiments of the present invention, the cerium-manganese binary metal oxide catalyst includes a composite oxide of MnO2 and CeO2.

[0016] According to some embodiments of the present invention, a ranges from 1 to 5, and x ranges from 4 to 12.

[0017] According to some embodiments of the present invention, the range of a is 2-3, and the range of x is 6-8.

[0018] According to some embodiments of the present invention, the cerium-manganese binary metal oxide catalyst has a degradation efficiency greater than 90% for toluene with a concentration of 1000-2000 ppm and a space velocity of 20000-30000 mL / (gh) at 210°C.

[0019] According to some embodiments of the present invention, the cerium-manganese binary metal oxide catalyst has a degradation efficiency of 90% at 205° C. for toluene with a concentration of 1000 ppm and a space velocity of 24000 mL / (gh).

[0020] According to a second embodiment of the present invention, there is provided a method for preparing the cerium-manganese binary metal oxide catalyst according to the first embodiment of the present invention, comprising the following steps:

[0021] The cerium salt is mixed with a manganese source and a solvent to carry out an oxidation-reduction reaction to obtain a cerium-manganese binary metal oxide catalyst;

[0022] The manganese source includes permanganate, or permanganate and a manganese salt with a valence of <+7; the temperature of the redox reaction is 50-100°C, and the time is 6-24h.

[0023] The preparation method of the cerium manganese binary metal oxide catalyst according to the embodiment of the present invention has at least the following beneficial effects: the present invention synthesizes the cerium manganese binary metal oxide catalyst in one step through a simple redox reaction, which is simpler than the prior art, does not require high-temperature and high-pressure equipment, is safe to operate, has low cost, does not require the preparation of precursors, and does not require subsequent calcination, and is easy to industrialize and mass produce. At the same time, the obtained catalyst has the characteristics of high specific surface area and high catalytic activity, and exhibits excellent catalytic degradation performance for toluene.

[0024] According to some embodiments of the present invention, the redox reaction is carried out by water bath heating, and the temperature of the redox reaction is 60-80°C.

[0025] According to some embodiments of the present invention, the redox reaction time is 8 to 24 hours.

[0026] According to some embodiments of the present invention, the redox reaction time is 8-12 hours.

[0027] According to some embodiments of the present invention, the cerium salt includes at least one of cerium sulfate, cerium nitrate, cerium acetate, and cerium chloride; or,

[0028] The permanganate includes at least one of potassium permanganate, sodium permanganate and calcium permanganate; or

[0029] The manganese salt with a valence of <+7 includes at least one of manganese sulfate, manganese nitrate, manganese acetate and manganese chloride.

[0030] According to some embodiments of the present invention, during the redox reaction, stirring is performed at a speed of 300 to 3000 rpm.

[0031] According to some embodiments of the present invention, during the redox reaction, stirring is performed at a speed of 500 to 1500 rpm.

[0032] According to some embodiments of the present invention, after the redox reaction is completed, the process further includes solid-liquid separation, water washing and drying of the reactants, wherein the drying temperature is 80 to 200° C. and the drying time is 4 to 48 hours.

[0033] According to some embodiments of the present invention, the solid-liquid separation equipment includes one of a vacuum filter, a high-speed centrifuge, and a plate-and-frame centrifuge.

[0034] According to some embodiments of the present invention, the drying temperature is 100-150°C.

[0035] According to some embodiments of the present invention, the drying time is 6 to 12 hours.

[0036] According to some embodiments of the present invention, the cerium-manganese binary metal oxide catalyst obtained after the drying treatment is a powdery cerium-manganese binary metal oxide catalyst.

[0037] According to some embodiments of the invention, the solvent is water.

[0038] According to a third aspect of the present invention, there is provided a use of the cerium-manganese binary metal oxide catalyst according to the first aspect of the present invention in the catalytic degradation of volatile organic compounds.

[0039] The application of the cerium-manganese binary metal oxide catalyst in the catalytic degradation of volatile organic compounds has at least the following beneficial effects: it can efficiently catalytically degrade volatile organic compounds at a relatively low temperature, especially efficiently catalytically degrade toluene, and has broader application prospects and good economic benefits.

[0040] According to a fourth embodiment of the present invention, there is provided a household appliance, wherein the household appliance comprises the cerium-manganese binary metal oxide catalyst according to the first embodiment of the present invention.

[0041] The household appliance according to the embodiment of the present invention has at least the following beneficial effects: the household appliance of the present invention, because it contains the cerium-manganese binary metal oxide catalyst of the present invention, can efficiently catalyze and degrade VOCs such as toluene in the air.

[0042] According to some embodiments of the present invention, the household appliance includes a heater, a fan heater, an electric oven, an air fryer, an air conditioner or an air purifier.

[0043] Additional aspects and advantages of the present invention will be given in part in the following description and in part will be obvious from the following description, or will be learned through practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0044] Figure 1 is an XRD comparison diagram of the catalysts of Example 1 of the present invention and Comparative Example 1;

[0045] Figure 2 It is a comparison chart of the catalytic degradation performance of toluene by the catalysts of Example 1 of the present invention and Comparative Example 1;

[0046] Figure 3 is a comparison chart of the catalytic degradation performance of toluene by the catalysts of Example 2 and Example 3 of the present invention;

[0047] Figure 4 is a SEM image of the catalyst of Example 2 of the present invention;

[0048] Figure 5 is a SEM image of the catalyst of Example 3 of the present invention;

[0049] Figure 6 2 are N2 adsorption curves and pore size distribution diagrams of the catalysts of Examples 2 and 3 of the present invention;

[0050] Figure 7 is a comparison chart of the catalytic degradation performance of toluene by the catalysts of Example 4, Example 5 and Example 6 of the present invention;

[0051] Figure 8 It is a comparison chart of the catalytic degradation performance of toluene by the catalysts of Example 3 and Example 4 of the present invention. DETAILED DESCRIPTION

[0052] Embodiments of the present invention are described in detail below. The described embodiments are exemplary and are only used to explain the present invention, and should not be construed as limiting the present invention.

[0053] One aspect of the present invention provides a cerium-manganese binary metal oxide catalyst, the chemical composition of the cerium-manganese binary metal oxide catalyst is as follows: CeMn a O x, wherein a ranges from 1 to 20, and x ranges from 4 to 42; the specific surface area of ​​the cerium-manganese binary metal oxide catalyst is ≥100m 2 / g.

[0054] It can be understood that the cerium-manganese binary metal oxide catalyst of the present invention has the characteristics of high specific surface area and high catalytic activity, thus showing excellent catalytic degradation performance for toluene.

[0055] In some embodiments of the present invention, the pore size of the cerium-manganese binary metal oxide catalyst is 2-50 nm.

[0056] In some embodiments of the present invention, the specific surface area of ​​the cerium-manganese binary metal oxide catalyst is 100-300m 2 / g.

[0057] In some embodiments of the present invention, the specific surface area of ​​the cerium-manganese binary metal oxide catalyst is 100-150m 2 / g.

[0058] In some embodiments of the present invention, the cerium-manganese binary metal oxide catalyst includes a composite oxide of MnO2 and CeO2.

[0059] In some embodiments of the present invention, a ranges from 1 to 5, and x ranges from 4 to 12. The present invention adjusts the crystal structure, morphology, specific surface area or pore size distribution of the obtained cerium-manganese binary metal oxide catalyst by adjusting the molar ratio of cerium and manganese elements, that is, the range of a, so as to adjust the catalytic degradation performance of the cerium-manganese binary metal oxide catalyst on VOCs. Too low a cerium content will result in an excessive amount of cerium oxide formed, which will not play a corresponding role in the composite; too low a manganese content will cause incomplete reaction of cerium salt. The present invention further controls the molar ratio of cerium and manganese elements to 1:1 to 1:5; further, a ranges from 2 to 3, and x ranges from 6 to 8. The present invention controls the molar ratio of cerium and manganese elements to 1:2 to 1:3, which is more conducive to the reaction, thereby improving the catalytic degradation performance of the cerium-manganese binary metal oxide catalyst on VOCs.

[0060] It is understandable that the present invention uses CeMn a O x The naming method of a is to clarify the value range of a in order to better distinguish the molar ratio of Ce / Mn in the reactants; and the value range of x is related to the value range of a and the actual valence states of cerium and manganese.

[0061] In some embodiments of the present invention, the cerium manganese binary metal oxide catalyst has a degradation efficiency greater than 90% at 210° C. for toluene with a concentration of 1000-2000 ppm and a space velocity of 20000-30000 mL / (gh).

[0062] In some embodiments of the present invention, the cerium-manganese binary metal oxide catalyst has a degradation efficiency of 90% for toluene with a concentration of 1000 ppm and a space velocity of 24000 mL / (gh) at 205°C.

[0063] It should be noted that the "space velocity" in the present invention refers to the amount of gas treated by a unit mass of catalyst per unit time under specified conditions. In some embodiments of the present invention, the space velocity is the flow rate of toluene divided by the mass of the catalyst.

[0064] Another aspect of the present invention provides a method for preparing the cerium-manganese binary metal oxide catalyst of the aforementioned embodiment, comprising the following steps:

[0065] The cerium salt is mixed with a manganese source and a solvent to carry out an oxidation-reduction reaction to obtain a cerium-manganese binary metal oxide catalyst;

[0066] The manganese source includes permanganate, or permanganate and a manganese salt with a valence of <+7; the temperature of the redox reaction is 50-100°C.

[0067] It is understood that the preparation method of the cerium-manganese binary metal oxide catalyst of the present invention synthesizes the cerium-manganese binary metal oxide catalyst in one step through a simple redox reaction, which is simpler to operate, has milder reaction conditions, and is safer than the prior art. Due to the simple preparation method and mild conditions, the obtained catalyst has high crystallinity and many active sites, and exhibits excellent catalytic degradation performance for toluene.

[0068] It can also be understood that the preparation method of the cerium-manganese binary metal oxide catalyst of the present invention does not require the high-temperature and high-pressure equipment used in the hydrothermal method, and is safe to operate and low in cost; it does not require the preparation of a precursor, the method is simple, and it is easy to industrialize and mass produce; it also does not require subsequent high-temperature calcination, saving energy.

[0069] In some embodiments of the present invention, a cerium salt, a solvent and a permanganate are mixed and subjected to a redox reaction to prepare a cerium-manganese binary metal oxide catalyst.

[0070] In some embodiments of the present invention, a cerium salt, a solvent, a permanganate and a manganese salt with a valence of less than +7 are mixed and subjected to a redox reaction to prepare a cerium-manganese binary metal oxide catalyst.

[0071] In some embodiments of the present invention, the redox reaction is heated in a water bath, and the temperature of the redox reaction is 60 to 80°C. The present invention adjusts the crystallinity and crystal form of the obtained cerium-manganese binary metal oxide catalyst by regulating the temperature of the redox reaction, thereby regulating the catalytic degradation performance of the cerium-manganese binary metal oxide catalyst on VOCs. The present invention further controls the temperature of the redox reaction at 60 to 80°C, which helps the obtained cerium-manganese binary metal oxide catalyst to have better crystallinity and crystal form, thereby improving the catalytic degradation performance of the cerium-manganese binary metal oxide catalyst on VOCs.

[0072] In some embodiments of the present invention, the time of the redox reaction is 6 to 24 hours. The present invention helps to obtain better crystallinity and crystal form by regulating the time of the redox reaction. The present invention further controls the time of the redox reaction to 8 to 24 hours; further, the present invention controls the time of the redox reaction to 8 to 12 hours, which helps to improve the catalytic degradation performance of the cerium-manganese binary metal oxide catalyst on VOCs.

[0073] In some embodiments of the present invention, the cerium salt includes at least one of cerium sulfate, cerium nitrate, cerium acetate, and cerium chloride.

[0074] In some embodiments of the present invention, the permanganate includes at least one of potassium permanganate, sodium permanganate, and calcium permanganate.

[0075] Furthermore, the permanganate of the present invention is potassium permanganate, which is cheaper than sodium permanganate, thereby saving costs.

[0076] In some embodiments of the present invention, the manganese salt with a valence of <+7 includes at least one of manganese sulfate, manganese nitrate, manganese acetate, and manganese chloride.

[0077] In some embodiments of the present invention, during the redox reaction, in order to promote the reaction, stirring is performed at a certain speed during the redox reaction, and the stirring speed is 300 to 3000 rpm.

[0078] Furthermore, the stirring speed is 500-1500 rpm.

[0079] In some embodiments of the present invention, after the redox reaction is complete, the reaction product is subjected to solid-liquid separation.

[0080] In some embodiments of the present invention, the precipitate obtained by solid-liquid separation is washed with water and dried.

[0081] In some embodiments of the present invention, the solid-liquid separation equipment includes one of a vacuum filter, a high-speed centrifuge, and a plate-and-frame centrifuge.

[0082] In some embodiments of the present invention, the drying temperature is 80-200°C.

[0083] In some embodiments of the present invention, the drying temperature is 100-150°C.

[0084] In some embodiments of the present invention, the drying time is 4 to 48 hours.

[0085] In some embodiments of the present invention, the drying time is 6 to 12 hours.

[0086] It is understandable that the present invention can avoid that the drying temperature is too low and the drying time is too long, and that the crystal structure of the cerium-manganese binary metal oxide catalyst may be destroyed due to too high a drying temperature, by regulating the drying temperature and the drying time.

[0087] In some embodiments of the present invention, the cerium-manganese binary metal oxide catalyst obtained after drying is a powdery cerium-manganese binary metal oxide catalyst.

[0088] In some embodiments of the present invention, the solvent is water.

[0089] Another aspect of the present invention provides use of the cerium-manganese binary metal oxide catalyst of the aforementioned embodiment in catalytic degradation of volatile organic compounds.

[0090] It can be understood that the cerium-manganese binary metal oxide catalyst of the present invention has high crystallinity and multiple active sites, and can efficiently catalyze the degradation of volatile organic compounds at a relatively low temperature, especially the efficient catalytic degradation of toluene, and has broader application prospects and good economic benefits.

[0091] Another aspect of the present invention provides a household appliance, wherein the household appliance contains the cerium-manganese binary metal oxide catalyst according to the aforementioned embodiment of the present invention.

[0092] It is easy to imagine that the household appliance of the present invention, because it contains the cerium-manganese binary metal oxide catalyst of the present invention, can efficiently catalyze and degrade VOCs such as toluene in the air.

[0093] In some embodiments of the present invention, the household appliance includes a heater, a fan heater, an electric oven, an air fryer, an air conditioner or an air purifier.

[0094] The present invention is further described in detail below by means of specific examples. Unless otherwise specified, the raw materials, reagents or devices used below can be obtained from conventional commercial sources. Unless otherwise specified, the experiments or test methods are conventional methods in the art.

[0095] Example 1

[0096] This example prepares a cerium-manganese binary metal oxide catalyst, and the specific preparation process is as follows:

[0097] Dissolve 5 mmol of cerium salt (cerium nitrate) in 60 mL of deionized water, stir evenly, add 15 mmol of potassium permanganate powder, and stir until the material is completely dissolved to obtain a mixed solution;

[0098] The mixed solution was placed in a water bath, and heated to 80°C in a water bath at a stirring speed of 1000 rpm;

[0099] After reacting for 24 h, the mixture was cooled to room temperature and then vacuum filtered to separate the solid and liquid. The solid product was then washed with water and dried in an oven at 100 °C for 12 h to obtain a cerium-manganese binary metal oxide catalyst named CeMn3O x -W.

[0100] Comparative Example 1

[0101] The difference between Comparative Example 1 and Example 1 is that the cerium-manganese binary metal oxide catalyst is prepared by a hydrothermal method in Comparative Example 1. The specific preparation process is as follows:

[0102] Dissolve 5 mmol of cerium salt (cerium nitrate) in 60 mL of deionized water, stir evenly, add 15 mmol of potassium permanganate powder, and stir until the material is completely dissolved to obtain a mixed solution;

[0103] The mixed solution was transferred to a 100 mL reactor and reacted at 120 °C for 24 h. After cooling to room temperature, solid-liquid separation was performed by vacuum filtration. The solid product was then washed with water and dried in an oven at 100 °C for 12 h to obtain a cerium-manganese binary metal oxide catalyst named CeMn3O x -H.

[0104] Example 2

[0105] This example prepares a cerium-manganese binary metal oxide catalyst, and the specific preparation process is as follows:

[0106] Dissolve 5 mmol of cerium salt (cerium nitrate) in 60 mL of deionized water, stir evenly, add 5 mmol of potassium permanganate powder, and stir until the material is completely dissolved to obtain a mixed solution;

[0107] The mixed solution was placed in a water bath, and heated to 80°C in a water bath at a stirring speed of 1000 rpm;

[0108] The reaction was continued for 8 h, and after cooling to room temperature, solid-liquid separation was performed by vacuum filtration. The solid product was then washed with water and dried in an oven at 100 °C for 12 h to obtain a cerium-manganese binary metal oxide catalyst named CeMnO x-W.

[0109] Example 3

[0110] This example prepares a cerium-manganese binary metal oxide catalyst, and the specific preparation process is as follows:

[0111] Dissolve 5 mmol of cerium salt (cerium nitrate) in 60 mL of deionized water, stir evenly, add 10 mmol of potassium permanganate powder, and stir until the material is completely dissolved to obtain a mixed solution;

[0112] The mixed solution was placed in a water bath, and heated to 80°C in a water bath at a stirring speed of 1000 rpm;

[0113] After reacting for 8 h, the solid-liquid separation was performed by vacuum filtration after cooling to room temperature. The solid product was then washed with water and dried in an oven at 100 °C for 12 h to obtain a cerium-manganese binary metal oxide catalyst named CeMn2O x -W.

[0114] Example 4

[0115] This example prepares a cerium-manganese binary metal oxide catalyst, and the specific preparation process is as follows:

[0116] Dissolve 5 mmol of cerium salt (cerium nitrate) in 60 mL of deionized water, stir evenly, add 50 wt.% manganese nitrate solution, until the solution contains 3.3 mmol of manganese nitrate, then add 6.7 mmol of potassium permanganate powder, stir until the material is completely dissolved, and obtain a mixed solution;

[0117] The mixed solution was placed in a water bath, and heated to 80°C in a water bath at a stirring speed of 1000 rpm;

[0118] After reacting for 8 h, the solid-liquid separation was performed by vacuum filtration after cooling to room temperature. The solid product was then washed with water and dried in an oven at 100 °C for 12 h to obtain a cerium-manganese binary metal oxide catalyst named CeMn2O x -W1.

[0119] Example 5

[0120] This example prepares a cerium-manganese binary metal oxide catalyst, and the specific preparation process is as follows:

[0121] Dissolve 5 mmol of cerium salt (cerium nitrate) in 60 mL of deionized water, stir evenly, add 50 wt.% manganese nitrate solution, until the solution contains 5 mmol of manganese nitrate, then add 10 mmol of potassium permanganate powder, stir until the material is completely dissolved, and obtain a mixed solution;

[0122] The mixed solution was placed in a water bath, and heated to 80°C in a water bath at a stirring speed of 1000 rpm;

[0123] After reacting for 8 h, the solid-liquid separation was performed by vacuum filtration after cooling to room temperature. The solid product was then washed with water and dried in an oven at 100 °C for 12 h to obtain a cerium-manganese binary metal oxide catalyst named CeMn3O x -W1.

[0124] Example 6

[0125] This example prepares a cerium-manganese binary metal oxide catalyst, and the specific preparation process is as follows:

[0126] Dissolve 5 mmol of cerium salt (cerium nitrate) in 60 mL of deionized water, stir evenly, add 50 wt.% manganese nitrate solution, until the solution contains 8.3 mmol of manganese nitrate, then add 16.7 mmol of potassium permanganate powder, stir until the material is completely dissolved, and obtain a mixed solution;

[0127] The mixed solution was placed in a water bath, and heated to 80°C in a water bath at a stirring speed of 1000 rpm;

[0128] After reacting for 8 h, the solid-liquid separation was performed by vacuum filtration after cooling to room temperature. The solid product was then washed with water and dried in an oven at 100 °C for 12 h to obtain a cerium-manganese binary metal oxide catalyst named CeMn5O x -W1.

[0129] Furthermore, the CeMn3O x -W and CeMn3O of Comparative Example 1 x -H XRD spectrum, the results are as follows Figure 1 As shown. Figure 1 It can be seen that the CeMn3O prepared in Example 1 x -W is a cerium-manganese mixture composed of MnO2 and CeO2. At the same time, the catalyst CeMn3O x -H, the crystallinity of manganese dioxide is higher than that of the catalyst CeMn3O x -W has a high crystallinity of manganese dioxide, which results in fewer active sites of the catalyst and thus poor catalytic performance.

[0130] Furthermore, the CeMn3O x -W and CeMn3O of Comparative Example 1 x -H catalytic degradation performance for toluene, the results are as follows Figure 2 As shown. Figure 2It can be seen that the CeMn3O x -W T 90 is 209°C, while the CeMn3O x -H of T 90 It is 233°C, which further illustrates that the catalytic performance of the catalyst prepared in Example 1 is better.

[0131] Furthermore, the CeMnO x -W and CeMn2O of Example 3 x -W catalytic degradation performance for toluene, the results are as follows Figure 3 As shown. Figure 3 It can be seen that the CeMnO x -W T 90 is 222°C, the CeMn2O of Example 3 x -W T 90 is 205℃, indicating that when potassium permanganate and cerium salt are used as raw materials, the catalytic degradation performance of toluene by catalysts prepared with different Ce / Mn ratios is different, and when the Ce / Mn ratio is 1:2, the catalytic effect is better.

[0132] Furthermore, the CeMnO x -W and CeMn2O of Example 3 x -W SEM spectrum, the results are as follows Figure 4 , Figure 5 As shown. Figure 4 , Figure 5 It can be seen that there is no obvious difference in the apparent morphology of the two catalysts, both of which have no fixed morphology and are mainly nanoparticles.

[0133] Furthermore, the CeMnO x -W and CeMn2O of Example 3 x -W N2 adsorption and pore size distribution, the results are as follows Figure 6 As shown. Figure 6 It can be seen that the pore structures of the two catalysts are mainly mesoporous, while CeMn2O x -W specific surface area (134m 2 / g) is greater than CeMnO x -W(111m 2 / g), which also leads to CeMn2O x -One of the reasons why the catalytic performance of W is better.

[0134] Furthermore, the CeMn2O x -W1, CeMn3O of Example 5 x-W1 and CeMn5O of ​​Example 6 x -W1 catalytic degradation performance for toluene, the results are as follows Figure 7 As shown. Figure 7 It can be seen that the CeMn2O x -W1T 90 At 220°C, the CeMn3O x -W1T 90 is 216°C, the CeMn5O x -W1T 90 It is 248℃, which means that when potassium permanganate, manganese salt with a valence < +7 and cerium salt are used as raw materials, the catalytic performance of catalysts prepared with different Ce / Mn ratios on toluene is also different. When the Ce / Mn ratio is 1:2 and 1:3, the catalytic effect is better than that of the catalyst with a Ce / Mn ratio of 1:5.

[0135] Furthermore, by comparing the CeMn2O x -W and CeMn2O of Example 4 x -W1 catalytic degradation performance for toluene, the results are as follows Figure 8 As shown. Figure 8 It can be seen that the CeMn2O x -W T 90 At 205°C, the CeMn2O x -W1T 90 The catalytic performance of the catalyst for toluene was also affected by the type of raw materials. Under the same Ce / Mn ratio, the catalyst CeMn2O prepared with two raw materials (potassium permanganate and cerium salt) x -W has better catalytic performance for toluene than the catalyst CeMn2O prepared from three raw materials (potassium permanganate, manganese salt with valence < +7 and cerium salt). x -W1.

[0136] It should be noted that the above test method for toluene degradation is a common test method in the literature. Specifically, the degradation temperature of toluene is T 90 It refers to the catalytic temperature corresponding to when the toluene degradation rate reaches 90%.

[0137] Example 7

[0138] A household appliance, the household appliance containing the catalyst CeMn2O of Example 3 x -W.

[0139] The household appliance prepared in this embodiment uses the catalyst CeMn2O x -W, can efficiently degrade toluene in the gas.

[0140] In some embodiments of the present invention, the household appliance includes a heater, a fan heater, an electric oven, an air fryer, an air conditioner or an air purifier.

[0141] In the description of this specification, the description with reference to the terms "some embodiments", "examples" or "specific embodiments" etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiments or examples are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner.

[0142] Although the embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the claims and their equivalents.

Claims

1. A cerium-manganese binary metal oxide catalyst, It is characterized in that The chemical composition of the cerium-manganese binary metal oxide catalyst is as follows: CeMn a O x , wherein a ranges from 1 to 20, and x ranges from 4 to 42; the specific surface area of ​​the cerium-manganese binary metal oxide catalyst is ≥100m 2 / g.

2. The cerium-manganese binary metal oxide catalyst according to claim 1, It is characterized in that The pore size of the cerium-manganese binary metal oxide catalyst is 2-50 nm.

3. The cerium-manganese binary metal oxide catalyst according to claim 1, It is characterized in that The specific surface area of ​​the cerium-manganese binary metal oxide catalyst is 100-150m 2 / g.

4. The cerium-manganese binary metal oxide catalyst according to claim 1, It is characterized in that The range of a is 1-5, and the range of x is 4-12.

5. A method for preparing the cerium-manganese binary metal oxide catalyst according to any one of claims 1 to 4, It is characterized in that The following steps are involved: The cerium salt is mixed with a manganese source and a solvent to carry out an oxidation-reduction reaction to obtain a cerium-manganese binary metal oxide catalyst; The manganese source includes permanganate, or permanganate and a manganese salt with a valence of <+7; the temperature of the redox reaction is 50-100°C, and the time is 6-24h.

6. The preparation method according to claim 5, It is characterized in that The cerium salt includes at least one of cerium sulfate, cerium nitrate, cerium acetate and cerium chloride; or, The permanganate includes at least one of potassium permanganate, sodium permanganate and calcium permanganate; or The manganese salt with a valence of <+7 includes at least one of manganese sulfate, manganese nitrate, manganese acetate and manganese chloride.

7. The preparation method according to claim 5, It is characterized in that During the redox reaction, stirring is performed at a speed of 300 to 3000 rpm.

8. The preparation method according to claim 5, It is characterized in that After the redox reaction is completed, the method further comprises the steps of solid-liquid separation, water washing and drying of the reactants. The drying temperature is 80 to 200° C. and the drying time is 4 to 48 hours.

9. Use of the cerium-manganese binary metal oxide catalyst according to any one of claims 1 to 4 in the catalytic degradation of volatile organic compounds.

10. A household appliance, It is characterized in that The household appliance contains the cerium-manganese binary metal oxide catalyst according to any one of claims 1 to 4.

11. The household appliance according to claim 10, It is characterized in that The household appliances include heaters, fan heaters, electric ovens, air fryers, air conditioners or air purifiers.

Images