Supported transition metal oxide catalyst as well as preparation method and application thereof

Abstract

The invention discloses a supported transition metal oxide catalyst as well as a preparation method and application thereof. The supported transition metal oxide catalyst comprises a porous carrier and a transition metal oxide supported on the porous carrier, the porous carrier contains pores with the pore diameter of 1-50 [mu] m, and the porosity of the porous carrier is not lower than 50%. The supported transition metal oxide catalyst disclosed by the invention has the characteristics of high loading capacity of transition metal oxide, good dispersity of transition metal elements and excellent catalytic effect, can be used for catalytic decomposition of organic matters such as grease and VOCs, and is suitable for the fields of self-cleaning of household appliances, indoor air purification and the like. The invention also provides a preparation method and application of the supported transition metal oxide catalyst.

Description

Technical Field

[0001] The present invention relates to the technical field of catalysts, and in particular to a supported transition metal oxide catalyst and a preparation method and application thereof. Background Art

[0002] Catalysts are widely used in the fields of petrochemicals, coal chemical industry, environmental protection, oil fume purification, etc., and have achieved good technical results, with considerable economic benefits and social value. Commonly used catalysts are divided into two categories: precious metals such as Pt and Pd and transition metal oxides. Among them, transition metal oxide catalysts have the advantages of simple preparation methods and low costs, and are more likely to be commercially applied.

[0003] In order to achieve better catalytic performance, the catalyst is generally required to have a higher specific surface area, so the size of the catalyst is usually in the submicron or even nanometer level. However, the size of the catalyst is too small and it is easy to aggregate, making it difficult to give full play to the advantages of its small size. Moreover, in most application scenarios, for example, when the catalyst needs to be applied to an adhesive or coating, the catalyst will be coated, affecting the catalytic efficiency and limiting the wide application of the catalyst. In the related art, a small-sized catalyst is loaded on a carrier with a larger size. On the one hand, the dispersed surface area of ​​the catalyst is increased, which can reduce the amount of catalyst used under the same conditions; on the other hand, in the subsequent molding process, the probability of the catalyst being coated is reduced, which can improve the catalytic performance.

[0004] At present, the main preparation method of the catalyst is: the carrier is impregnated in a metal salt solution, and then dried and calcined at high temperature to prepare a supported metal oxide catalyst. This method has the following disadvantages: the loading amount of the catalyst in the impregnation process is generally low (<10wt%), which cannot meet the application requirements of high loading amount; the catalyst is unevenly distributed and the catalytic activity is low; the temperature of high-temperature calcination is generally 300-700℃, the energy consumption is high, and toxic and harmful substances such as nitrogen oxides are produced during the calcination process, which is not environmentally friendly; some methods have complicated steps, slow reaction speed, low production efficiency, high cost, etc. Therefore, it is still necessary to develop a supported transition metal oxide catalyst with uniform catalyst dispersion, good catalytic effect, and easier preparation. Summary of the invention

[0005] The present invention aims to solve at least one of the technical problems existing in the prior art. To this end, the present invention provides a supported transition metal oxide catalyst, which has the characteristics of high transition metal oxide loading capacity, good transition metal element dispersibility, and excellent catalytic effect.

[0006] The invention also provides a method for preparing a supported transition metal oxide catalyst.

[0007] The present invention also proposes the application of the above-mentioned supported transition metal oxide catalyst.

[0008] The present invention also provides a coating layer containing the above-mentioned supported transition metal oxide catalyst.

[0009] The present invention also provides a household appliance product containing the supported transition metal oxide catalyst or the coating.

[0010] The first embodiment of the present invention relates to a supported transition metal oxide catalyst, comprising:

[0011] A porous carrier, wherein the porous carrier contains pores with a pore size of 1-50 μm, and the porosity of the porous carrier is not less than 50%;

[0012] A transition metal oxide is supported on the porous support.

[0013] The supported transition metal oxide catalyst according to the first embodiment of the present invention has at least the following beneficial effects:

[0014] The porous carrier contains micron-sized pores with a pore size of 1-50 μm and a porosity of more than 50%. Based on the particularity of the pore structure of the porous carrier, a certain dispersion space and dispersible area are provided for the attachment of transition metal oxides, which is beneficial for the transition metal oxides to be coated on the surface of the porous carrier and its pore structure, thereby increasing the loading amount and dispersion uniformity of the transition metal oxides and improving the catalytic activity.

[0015] The supported transition metal oxide catalyst of this embodiment has an excellent catalytic effect. At the same time, since the porous carrier has a special pore structure, when applied to scenarios such as coatings, it can increase the surface roughness, expose more transition metal oxides, enhance catalytic performance, and better meet the application requirements of different scenarios.

[0016] According to some embodiments of the first aspect of the present invention, in the transition metal oxide, the transition metal element is selected from at least one of iron, cerium, cobalt and manganese.

[0017] According to some embodiments of the first aspect of the present invention, in the transition metal oxide, the transition metal elements are selected from at least two of iron, cerium, cobalt and manganese.

[0018] According to some embodiments of the first aspect of the present invention, in the transition metal oxide, the transition metal elements are selected from at least two of cerium, cobalt, and manganese.

[0019] According to some embodiments of the first aspect of the present invention, in the transition metal oxide, the transition metal elements include cerium, cobalt and manganese.

[0020] According to some embodiments of the first aspect of the present invention, the chemical formula of the transition metal oxide is Co x Ce y Mn 1-(x+y) O z , where 0.05≤x≤0.6, 0.05≤y≤0.6, 1.0≤z≤2.0.

[0021] According to some embodiments of the first aspect of the present invention, the Co x Ce y Mn 1-(x+y) O z Among them, 0.1≤x≤0.6, 0.2≤y≤0.6, 1.2≤z≤2.0.

[0022] By adjusting the ratio of transition metal elements, better catalytic performance can be obtained.

[0023] According to some embodiments of the first aspect of the present invention, the content of the transition metal oxide is 20%-70% of the mass of the porous support.

[0024] The loading amount of transition metal oxide is as high as 70% of the mass of the porous carrier, and the specific loading amount can be adjusted, for example, by changing the ratio of transition metal elements and porous carrier to meet the application requirements in different fields.

[0025] According to some embodiments of the first aspect of the present invention, the content of the transition metal oxide is 25%-70% of the mass of the porous support.

[0026] According to some embodiments of the first aspect of the present invention, the content of the transition metal oxide is 25%-50% of the mass of the porous support.

[0027] According to some embodiments of the first aspect of the present invention, the content of the transition metal oxide is 25%-30% of the mass of the porous carrier. Under this loading amount, an excellent catalytic effect can be achieved and the cost can be reduced.

[0028] According to some embodiments of the first aspect of the present invention, the porosity of the porous carrier is 50%-80%. Within the above porosity range, a high transition metal oxide loading and excellent catalytic effect can be obtained.

[0029] According to some embodiments of the first aspect of the present invention, the porous carrier is selected from α-Al 2 O 3 ,γ-Al 2 O 3 、SiO 2 、TiO 2 、ZrO 2, diatomaceous earth, and molecular sieve.

[0030] According to some embodiments of the first aspect of the present invention, the porous carrier is γ-Al 2 O 3 .

[0031] According to some embodiments of the first aspect of the present invention, the average particle size of the porous carrier is 20-250 μm.

[0032] When applied to polymer matrices such as coatings, the larger the particle size of the porous carrier, the rougher the surface structure can be, which is beneficial to improving catalytic performance. However, when the particle size is too large, it is easy to cause insufficient coating bonding, which is detrimental to mechanical properties. Within the above particle size range, the catalytic effect and comprehensive performance can be better balanced.

[0033] According to some embodiments of the first aspect of the present invention, the average particle size of the porous carrier is 50-150 μm, for example, 50 μm, 75 μm, 100 μm, 125 μm, or 150 μm.

[0034] According to some embodiments of the first aspect of the present invention, the porous carrier is a primary particle or a secondary particle. The primary particle refers to particles that are not stacked and are mainly in a single particle dispersion form; the secondary particle is an aggregated particle formed by stacking primary particles. As an example, the porous carrier can be a secondary particle formed by stacking flaky aluminum oxide, for example, a γ-Al2O3 with a sheet diameter of about 5-10 μm can be used. 2 O 3 Pieces are piled up.

[0035] According to some embodiments of the first aspect of the present invention, the porous carrier is a nearly spherical structure. In addition, it can also be an irregular shape.

[0036] According to some embodiments of the first aspect of the present invention, the porous carrier contains pores with a pore size of 1-20 μm. Within this pore size range and the defined porosity range, it is more conducive to improving the dispersibility of the transition metal oxide and enhancing the catalytic activity.

[0037] According to some embodiments of the first aspect of the present invention, the porous carrier comprises pores with a pore size of 1-10 μm.

[0038] According to some embodiments of the first aspect of the present invention, the porous carrier comprises pores with a pore size of 5-10 μm.

[0039] It is understood that the pore structure of the porous carrier is preferably a through-hole structure, so as to facilitate the attachment of the transition metal oxide to the internal pores of the porous carrier and increase the loading amount of the catalyst. The pores may be irregular in shape or regular in shape such as spherical or nearly spherical.

[0040] It can be understood that in addition to the pore size range defined in the above embodiment, the porous carrier may also contain pores of smaller size. For example, depending on the type of carrier material, it itself may also contain more microscopic nanoscale pores. These pores are small in size, and it is not easy for the transition metal oxide to penetrate deeply into the pores. Instead, they are easily blocked at the pore mouths, which has limited effect on improving catalytic performance. In addition, the volume of these pores is limited, and their contribution to porosity can be ignored.

[0041] It is understood that in addition to grease, transition metal oxides can also catalyze the decomposition of VOCs, for example, benzene, toluene, xylene, formaldehyde, trimethylamine, methyl mercaptan and other organic substances, and the catalytic mechanism is similar: the pollutants (grease or VOCs) are in contact with the catalyst surface, and under aerobic conditions, the pollutants can be decomposed into carbon dioxide, water and other small molecules at a lower temperature. Since the supported transition metal oxide catalyst of the embodiment of the present invention has a better catalytic activity, it is also more advantageous in catalytic decomposition of VOCs than the unsupported transition metal oxide.

[0042] According to some embodiments of the first aspect of the present invention, the fat comprises animal oil or vegetable oil.

[0043] According to some embodiments of the first aspect of the present invention, the animal oil includes lard, chicken fat, beef tallow, mutton fat or fish oil.

[0044] According to some embodiments of the first aspect of the present invention, the vegetable oil comprises peanut oil, rapeseed oil, corn oil, soybean oil or sunflower oil.

[0045] The second embodiment of the present invention relates to a method for preparing the above-mentioned supported transition metal oxide catalyst, comprising the steps of:

[0046] The method is prepared by subjecting an oxidant containing a transition metal element and a reductant containing a transition metal element to a redox precipitation reaction in the presence of the porous carrier.

[0047] The method for preparing a supported transition metal oxide catalyst according to the second aspect of the present invention has at least the following beneficial effects:

[0048] By adopting the redox precipitation method, an oxidant containing transition metal elements and a reductant containing transition metal elements are reacted in one step in situ on a porous carrier to obtain a supported transition metal oxide catalyst. The formed transition metal oxide can be fully coated on the surface of the porous carrier and its pore structure, and the transition metal elements are evenly distributed and well dispersed on the carrier surface, thereby improving the catalytic activity. The prepared catalyst has an excellent catalytic effect.

[0049] The preparation method of this embodiment has simple process, low energy consumption, low carbon and energy saving, no toxic and harmful gas emissions, safety and environmental protection, low production cost, effectively overcomes the shortcomings of the existing high-temperature calcination method, and is conducive to the realization of industrial production.

[0050] According to some embodiments of the second aspect of the present invention, the method for preparing the supported transition metal oxide catalyst comprises the steps of:

[0051] The porous carrier is dispersed in a solution containing an oxidant of a transition metal element, and then a solution containing a reductant of a transition metal element is added to obtain a first mixed solution, and a redox precipitation reaction is performed; or,

[0052] The porous carrier is dispersed in a solution of a reducing agent containing a transition metal element, and then a solution of an oxidizing agent containing a transition metal element is added to obtain a second mixed solution, and a redox precipitation reaction is performed.

[0053] First, the porous carrier is dispersed in the oxidant solution or the reductant solution, so that the surface of the porous carrier is impregnated with the oxidant or the reductant, and then the remaining components are added for reaction, which is conducive to the effective loading of the transition metal oxide on the surface of the porous carrier and improves the loading amount and loading uniformity. If the oxidant solution and the reductant solution are mixed and then added to the porous carrier, the redox precipitation reaction occurs during the impregnation process, which is easy to block the pores and makes it difficult to increase the loading amount.

[0054] It can be understood that the preparation method of this embodiment has the beneficial effects of the aforementioned preparation method embodiments. In addition, it can significantly increase the loading amount of transition metal oxides (up to 70% of the mass of the porous carrier). By changing the ratio of transition metal elements and porous carriers, the loading amount of transition metal oxides can be adjusted to meet the application requirements of different fields.

[0055] It should be noted that, in addition to the redox precipitation method, a direct precipitation method can also be used to prepare a supported transition metal oxide catalyst, which is a transition metal salt as a metal source, and is prepared by an in-situ reaction on the surface of a porous support by a precipitation method. Specifically, a transition metal hydroxide can be formed by an in-situ reaction on the surface of a porous support by a precipitation method, and then calcined to form a transition metal oxide. The process of preparing transition metal oxides by direct precipitation is an existing mature technology and will not be described in detail. Based on the special pore structure characteristics of the porous support of this implementation, a high loading can be obtained by direct precipitation, but the distribution uniformity of the transition metal element is not as good as the redox precipitation method, and thus when the catalyst content is equivalent, the catalytic performance may not be as good as the catalyst obtained by the redox precipitation method.

[0056] According to some embodiments of the second aspect of the present invention, the oxidant includes potassium permanganate or iron salt, and the reducing agent includes at least one of ferrous salt, cerium salt, cobalt salt and manganese salt.

[0057] According to some embodiments of the second aspect of the present invention, the iron salt, ferrous salt, cerium salt, cobalt salt and manganese salt are each independently selected from at least one of the sulfates, nitrates, acetates or chlorides of the corresponding transition metal elements.

[0058] According to some embodiments of the second aspect of the present invention, the oxidant is potassium permanganate.

[0059] According to some embodiments of the second aspect of the present invention, the pH of the redox precipitation reaction is ≥7.

[0060] According to some embodiments of the second aspect of the present invention, the pH of the redox precipitation reaction is 7-10.

[0061] According to some embodiments of the second aspect of the present invention, a co-reactant is further added during the redox precipitation reaction.

[0062] According to some embodiments of the second aspect of the present invention, the co-reactant is a base, which can adjust the pH, accelerate the reaction rate, and improve the yield.

[0063] According to some embodiments of the second aspect of the present invention, the co-reactant includes at least one of potassium hydroxide, sodium hydroxide, lithium hydroxide, ammonia water and urea.

[0064] According to some embodiments of the second aspect of the present invention, the concentration of the solution containing the oxidant of the transition metal element is 0.02-1.6 mol / L.

[0065] According to some embodiments of the second aspect of the present invention, the concentration of the solution containing the oxidant of the transition metal element is 0.02-1 mol / L.

[0066] According to some embodiments of the second aspect of the present invention, the concentration of the solution containing the oxidant of the transition metal element is 0.02-0.5 mol / L.

[0067] According to some embodiments of the second aspect of the present invention, the concentration of the solution containing the reducing agent of the transition metal element is 0.02-4 mol / L.

[0068] According to some embodiments of the second aspect of the present invention, the concentration of the solution containing the reducing agent of the transition metal element is 0.02-2 mol / L.

[0069] According to some embodiments of the second aspect of the present invention, the concentration of the solution containing the reducing agent of the transition metal element is 0.02-5 mol / L.

[0070] When the reducing agent contains multiple salts, the multiple salts can be prepared into a mixed solution, or each salt can be prepared into a solution separately and then added separately. It can be understood that when the reducing agent contains multiple salts, the above concentration range refers to the total concentration range of all salts.

[0071] According to some embodiments of the second aspect of the present invention, the solution containing the oxidant of the transition metal element is a potassium permanganate solution, and the solution containing the reducing agent of the transition metal element is a solution of a cerium salt and a cobalt salt. Wherein, the concentration of the potassium permanganate solution can be selected with reference to the concentration range of the solution containing the oxidant of the transition metal element in the above embodiment, and similarly, the concentration range of the solution of the cerium salt and the cobalt salt can be selected with reference to the concentration range of the solution containing the reducing agent of the transition metal element in the above embodiment. The cerium salt and the cobalt salt can be prepared into a mixed solution, or the cerium salt solution and the cobalt salt solution can be prepared separately and then added separately.

[0072] According to some embodiments of the second aspect of the present invention, the method further includes the step of adding a co-reactant to the first mixed solution or the second mixed solution to carry out a redox precipitation reaction.

[0073] According to some embodiments of the second aspect of the present invention, a co-reactant is added to the first mixed solution or the second mixed solution to adjust the pH to pH ≥ 7. By adjusting the pH to a suitable range, the reaction rate can be accelerated and the yield can be improved.

[0074] According to some embodiments of the second aspect of the present invention, a co-reactant is added to the first mixed solution or the second mixed solution to adjust the pH to 7-10.

[0075] According to some embodiments of the second aspect of the present invention, the porous carrier is dispersed in a solution containing an oxidant of a transition metal element, or the porous carrier is dispersed in a solution containing a reductant of a transition metal element, wherein stirring is performed during the dispersion process.

[0076] According to some embodiments of the second aspect of the present invention, the stirring rate is 300-1000 rpm.

[0077] According to some embodiments of the second aspect of the present invention, the stirring rate is 400-600 rpm, for example, it can be 400 rpm, 500 rpm, 600 rpm.

[0078] According to some embodiments of the second aspect of the present invention, the stirring time is not less than 0.1 h.

[0079] According to some embodiments of the second aspect of the present invention, the stirring time is not less than 0.5 h, for example, it can be 0.5-1 h.

[0080] According to some embodiments of the second aspect of the present invention, the stirring is performed at 20-100°C.

[0081] According to some embodiments of the second aspect of the present invention, the stirring is performed at 50-80°C.

[0082] According to some embodiments of the second aspect of the present invention, the temperature of the redox precipitation reaction is 20-100°C.

[0083] According to some embodiments of the second aspect of the present invention, the temperature of the redox precipitation reaction is 50-80°C.

[0084] According to some embodiments of the second aspect of the present invention, the redox precipitation reaction time is 1-10 hours.

[0085] According to some embodiments of the second aspect of the present invention, the redox precipitation reaction time is 2-4 hours.

[0086] The redox precipitation reaction has low reaction temperature, short reaction time, energy conservation and environmental protection, and reduces production costs.

[0087] According to some embodiments of the second aspect of the present invention, the following steps are further included: performing solid-liquid separation after the redox precipitation reaction, and drying the obtained solid phase.

[0088] According to some embodiments of the second aspect of the present invention, the drying temperature is 80-150°C.

[0089] According to some embodiments of the second aspect of the present invention, the drying temperature is 100-120°C.

[0090] According to some embodiments of the second aspect of the present invention, the drying time is 4-12 hours.

[0091] According to some embodiments of the second aspect of the present invention, the drying time is 6-10 hours.

[0092] According to some embodiments of the second aspect of the present invention, before drying, the solid phase obtained is further washed by water.

[0093] According to some embodiments of the second aspect of the present invention, the solid-liquid separation is performed by filtration or centrifugation.

[0094] The third embodiment of the present invention relates to the use of the above-mentioned supported transition metal oxide catalyst in the catalytic decomposition of organic matter.

[0095] The use of the supported transition metal oxide catalyst in the catalytic decomposition of organic matter according to the third aspect of the present invention has at least the following beneficial effects:

[0096] In the application of the embodiment of the present invention, since the above-mentioned supported transition metal oxide catalyst is contained, at least all the beneficial effects of the above-mentioned supported transition metal oxide catalyst embodiment are present. For example, the supported transition metal oxide catalyst has the advantages of high load capacity of transition metal oxide (up to 70% of the weight of the porous carrier), adjustable load capacity, and good dispersibility of transition metal elements, and has excellent catalytic effect, and can be used for catalytic decomposition of organic matter such as grease and VOCs, with a decomposition rate of up to 99%, and is suitable for self-cleaning of household appliances such as ovens, air fryers, heaters (such as skirting heaters), refrigerators, washing machines, and indoor air purification (such as formaldehyde removal, toluene removal, oil fume removal, etc.) and other fields.

[0097] According to some embodiments of the third aspect of the present invention, the organic matter includes oil or VOCs.

[0098] The fourth aspect of the present invention relates to a coating, wherein the raw materials for preparing the coating include the supported transition metal oxide catalyst.

[0099] The coating according to the fourth aspect of the present invention has at least the following beneficial effects:

[0100] The coating of the embodiment of the present invention, because it contains the above-mentioned supported transition metal oxide catalyst, has at least all the beneficial effects of the above-mentioned supported transition metal oxide catalyst embodiment. For example, the supported transition metal oxide catalyst has the advantages of high load capacity of transition metal oxide (up to 70% of the weight of the porous carrier), adjustable load capacity, and good dispersibility of transition metal elements. It has excellent catalytic effect and can be used for catalytic decomposition of organic matter such as grease and VOCs, with a decomposition rate of up to 99%. Since the porous carrier has a special pore structure, when it is applied to scenes such as coatings, it can improve the surface roughness, expose more transition metal oxides, and improve catalytic performance. It can well decompose grease on the surface of household appliances, or organic matter such as grease and VOCs in the air.

[0101] According to some embodiments of the fourth aspect of the present invention, the dry film thickness of the coating is 50-250 μm.

[0102] According to some embodiments of the fourth aspect of the present invention, the dry film thickness of the coating is 75-125 μm.

[0103] According to some embodiments of the fourth aspect of the present invention, the roughness of the coating is 5-40 μm.

[0104] According to some embodiments of the fourth aspect of the present invention, the roughness of the coating is 10-25 μm.

[0105] According to some embodiments of the fourth aspect of the present invention, the coating comprises a resin and the supported transition metal oxide catalyst.

[0106] According to some embodiments of the fourth aspect of the present invention, the weight fraction of the supported transition metal oxide catalyst in the coating is 30%-90%. Within the limited catalyst content range, as the amount of catalyst increases, the catalytic effect of the coating is more guaranteed, but the cost will also increase.

[0107] According to some embodiments of the fourth aspect of the present invention, in the coating, the mass fraction of the supported transition metal oxide catalyst is 40%-80%.

[0108] According to some embodiments of the fourth aspect of the present invention, the raw materials for preparing the coating include the following components in percentage by mass: 15%-35% resin, 30%-50% catalyst, and 0%-45% solvent.

[0109] The mass fraction of the catalyst is about 46.2%-76.9% calculated based on the dry weight of the coating (excluding the solvent).

[0110] The resin mainly plays a role of bonding, and resin types known in the art may be used, for example, polyamide, etc. When no solvent is contained, the resin may be a liquid resin.

[0111] In addition to the above components, an appropriate amount of auxiliary agents such as a wetting agent and a thickener may also be added to the coating.

[0112] Among them, the main function of the wetting agent is to wet the substrate and improve the leveling of the coating. Commonly used wetting agents include polyethers, silicones, etc. The amount of the wetting agent can be 0.1%-2% of the total weight of the component.

[0113] The main function of thickener is to adjust the viscosity and improve the coating performance of the coating. Commonly used thickeners include xanthan gum, polyamide wax, etc. The amount of thickener can be 0.5%-5% of the total weight of the components.

[0114] According to some embodiments of the fourth aspect of the present invention, in the raw materials for preparing the coating, the solvent is selected from ketones or esters. For example, the solvent can be selected from at least one of butyl acetate and NMP.

[0115] According to some embodiments of the fourth aspect of the present invention, when the coating is used for catalytic decomposition of grease, the added amount of the supported transition metal oxide catalyst satisfies: wherein the added amount of the transition metal oxide is not higher than 1 mg / g grease.

[0116] A fifth aspect of the present invention relates to a household appliance, wherein the household appliance contains the above-mentioned supported transition metal oxide catalyst or the above-mentioned coating.

[0117] The household appliance according to the fifth aspect of the present invention has at least the following beneficial effects:

[0118] The household appliance of the embodiment of the present invention contains the above-mentioned supported transition metal oxide catalyst, and therefore has at least all the beneficial effects of the above-mentioned supported transition metal oxide catalyst embodiment. Furthermore, the household appliance has an excellent catalytic decomposition effect on organic matter such as grease and VOCs, with a decomposition rate of up to 99%, and can be used to catalytically decompose grease in household appliances, and organic matter such as grease and VOCs in the air.

[0119] According to some embodiments of the fifth aspect of the present invention, the household appliance includes an oven, an air fryer, a heater, a range hood, a refrigerator, a washing machine or an air purifier.

[0120] 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

[0121] Figure 1 The porous carrier γ-Al in Example 1 2 O 3 SEM image of .

[0122] Figure 2 25wt%-Co prepared in Example 1 0.1 Ce 0.5 Mn 0.4 O z @γ-Al 2 O 3 SEM image of .

[0123] Figure 3 11wt%-Co prepared in Example 6 0.1 Ce 0.5 Mn 0.4 O z @γ-Al 2 O 3 SEM image of .

[0124] Figure 4 7wt%-Co prepared in Example 7 0.1 Ce 0.5 Mn 0.4 O z @γ-Al 2 O 3 SEM image of .

[0125] Figure 5 Co prepared in Comparative Example 1 0.1 Ce 0.5 Mn 0.4 O z SEM image of .

[0126] Figure 6 The conventional γ-Al in Comparative Example 2 2 O 3 SEM image of the carrier.

[0127] Figure 7 4wt%-Co prepared in Comparative Example 2 0.1 Ce 0.5 Mn 0.4 O z @γ-Al 2 O 3 -SEM image of C.

[0128] Figure 8 For comparative example 1 ( Figure 8 a) and Example 1 ( Figure 8 b) Photograph of the coating made of the resulting catalyst after decomposition of chicken fat.

[0129] Fig. 9 This is a surface morphology of a coating prepared using the catalyst prepared in Comparative Example 1.

[0130] Fig.10 This is a surface morphology of a coating prepared using the catalyst prepared in Example 1. DETAILED DESCRIPTION

[0131] Embodiments of the present invention are described in detail below. The embodiments are exemplary and are only used to explain the present invention, but are not to be construed as limiting the present invention.

[0132] In the following examples, the relevant raw materials are described as follows:

[0133] Porous carrier: mainly composed of γ-Al with a sheet diameter of about 5-10μm 2 O 3 The porous carrier is stacked with sheets, the average particle size of the porous carrier is 50-125 μm, the pore size range is 1-20 μm, and the porosity is 50%-80%, which is purchased from Zibo Aotai New Material Technology Co., Ltd.

[0134] Example 1

[0135] In this example, a supported cobalt-cerium-manganese ternary metal oxide catalyst was prepared, denoted as 25wt%-Co 0.1 Ce 0.5 Mn 0.4 Oz @γ-Al 2 O 3 , z is 1.2-2.0, and the specific value is related to the actual valence state of the transition metal element and the vacancies in the material; 25wt% means Co 0.1 Ce 0.5 Mn 0.4 O z γ-Al 2 O 3 The mass fraction is 25%.

[0136] The preparation process is:

[0137] Prepare 0.4L of 0.2mol / L potassium permanganate solution, heat to 80℃ in a water bath, and stir at 500rpm. First add 103.9g of porous carrier γ-Al 2 O 3 (The average particle size is 75 μm, and the morphology is Figure 1 As shown), continue to stir and disperse for 0.5h; then add 0.2L of 0.1mol / L cobalt nitrate solution and 0.2L of 0.5mol / L cerium nitrate solution, and continue to add 4mol / L potassium hydroxide as a co-reactant to adjust the solution pH to 7; after reacting for 2h, filter, wash with water, and dry in a 100℃ forced air oven for 8h to obtain a supported cobalt-cerium-manganese trimetallic oxide catalyst. The morphology of the supported cobalt-cerium-manganese ternary metal oxide catalyst is as shown Figure 2 shown.

[0138] Depend on Figure 1 It can be seen that the porous support γ-Al 2 O 3 The interior and surface present an irregular porous structure, with the pore size mainly ranging from 1 to 10 μm, which is conducive to the attachment of transition metal oxides. Figure 1 In the , there are a few particles that do not have obvious micron-scale pore structure, which is difficult to avoid in the carrier preparation process, but the amount of these particles is very small and has little effect on the overall performance. Figure 2 It can be seen that the supported cobalt-cerium-manganese trimetallic oxide catalyst prepared in this embodiment is completely coated on the γ-Al 2 O 3 The catalyst loading uniformity is good on the carrier surface and in its pores.

[0139] Example 2

[0140] In this example, a supported cobalt-cerium-manganese ternary metal oxide catalyst was prepared, denoted as 70 wt%-Co 0.1 Ce 0.5 Mn 0.4 O z @γ-Al 2 O 3, z is 1.2-2.0, and the specific value is related to the actual valence state of the transition metal element and the vacancies in the material; 70wt% means Co 0.1 Ce 0.5 Mn 0.4 O z γ-Al 2 O 3 The mass fraction is 70%.

[0141] The preparation process is:

[0142] Prepare 0.4L of 0.2mol / L potassium permanganate solution, heat to 80℃ in a water bath, and stir at 500rpm. First, add 39.0g of porous carrier γ-Al 2 O 3 (The average particle size is 75 μm, and the morphology is Figure 1 As shown), continue to stir and disperse for 0.5h; then add 0.2L of 0.1mol / L cobalt nitrate solution and 0.2L of 0.5mol / L cerium nitrate solution, and continue to add 4mol / L potassium hydroxide as a co-reactant to adjust the solution pH to 7; after reacting for 2h, filter, wash with water, and dry in a 100°C blast oven for 8h to obtain a supported cobalt-cerium-manganese trimetallic oxide catalyst.

[0143] Example 3

[0144] In this example, a supported cobalt-manganese binary metal oxide catalyst was prepared, denoted as 25 wt%-Co 0.6 Mn 0.4 O z @γ-Al 2 O 3 , z is 1.2-2.0, and the specific value is related to the actual valence state of the transition metal element and the vacancies in the material; 25wt% means Co 0.6 Mn 0.4 O z γ-Al 2 O 3 The mass fraction is 25%.

[0145] The preparation process is:

[0146] Prepare 0.4L of 0.2mol / L potassium permanganate solution, heat to 80℃ in a water bath, and stir at 500rpm. First add 71.5g of porous carrier γ-Al 2 O 3(average particle size is 100 μm), continue stirring and dispersing for 0.5 h; then add 0.4 L of 0.3 mol / L cobalt nitrate solution, and continue to add 4 mol / L potassium hydroxide as a co-reactant to adjust the solution pH to 7; after reacting for 2 h, filter, wash with water, and dry in a 100°C forced air oven for 8 h to obtain a supported cobalt-manganese binary metal oxide catalyst.

[0147] Example 4

[0148] This example prepares a supported cerium-manganese binary metal oxide catalyst, denoted as 25wt%-Ce 0.6 Mn 0.4 O z @γ-Al 2 O 3 , z is 1.2-2.0, and the specific value is related to the actual valence state of the transition metal element and the vacancies in the material; 25wt% means Ce 0.6 Mn 0.4 O z γ-Al 2 O 3 The mass fraction is 25%.

[0149] The preparation process is:

[0150] Prepare 0.4L of 0.2mol / L potassium permanganate solution, heat to 80℃ in a water bath, and stir at 500rpm. First add 110.4g of porous carrier γ-Al 2 O 3 (average particle size is 125 μm), continue stirring and dispersing for 0.5 h; then add 0.4 L of 0.3 mol / L cerium nitrate solution, and continue to add 4 mol / L potassium hydroxide as a co-reactant to adjust the solution pH to 7; after reacting for 2 h, filter, wash with water, and dry in a 100°C forced air oven for 8 h to obtain a supported cerium-manganese binary metal oxide catalyst.

[0151] Example 5

[0152] In this example, a supported manganese oxide catalyst was prepared, denoted as 25wt%-MnO z @γ-Al 2 O 3 , z takes a value of 1.2-2.0, and the specific value is related to the actual valence state of the transition metal element and the vacancies in the material; 25wt% means MnO z γ-Al 2 O 3 The mass fraction is 25%.

[0153] The preparation process is:

[0154] Prepare 0.4L of 0.2mol / L potassium permanganate solution, heat to 80℃ in a water bath, and stir at 500rpm. First add 69.6g of porous carrier γ-Al 2 O 3 (average particle size is 50 μm), continue stirring and dispersing for 0.5 h; then add 0.4 L of 0.3 mol / L cerium nitrate solution, and continue to add 4 mol / L potassium hydroxide as a co-reactant to adjust the solution pH to 7; after reacting for 2 h, filter, wash with water, and dry in a 100°C forced air oven for 8 h to obtain a supported manganese oxide catalyst.

[0155] Example 6

[0156] In this example, a supported cobalt-cerium-manganese ternary metal oxide catalyst was prepared, denoted as 11 wt%-Co 0.1 Ce 0.5 Mn 0.4 O z @γ-Al 2 O 3 , z is 1.2-2.0, and the specific value is related to the actual valence state of the transition metal element and the vacancies in the material; 11wt% means Co 0.1 Ce 0.5 Mn 0.4 O z γ-Al 2 O 3 The mass fraction is 11%.

[0157] The preparation method thereof refers to Example 1, except that a porous carrier γ-Al is added. 2 O 3 The stirring rate before and after was 1000 rpm. The morphology of the prepared supported cobalt-cerium-manganese ternary metal oxide catalyst is as follows: Figure 3 shown.

[0158] Combination Figure 3 It can be seen that increasing the stirring rate not only reduces the catalyst loading, but also the loading uniformity is obviously not as good as in Example 1 (see Figure 2 ). The experimental results show that within a certain stirring rate range, it is more conducive to the loading of transition metal oxides and improves the loading amount and loading uniformity.

[0159] Example 7

[0160] In this example, a supported cobalt-cerium-manganese ternary metal oxide catalyst was prepared, denoted as 7wt%-Co 0.1 Ce 0.5 Mn 0.4 O z @γ-Al 2 O 3, z is 1.2-2.0, and the specific value is related to the actual valence state of the transition metal element and the vacancies in the material; 7wt% means Co 0.1 Ce 0.5 Mn 0.4 O z γ-Al 2 O 3 The mass fraction is 7%.

[0161] The preparation method thereof refers to Example 6, except that the porous carrier γ-Al 2 O 3 The order of addition is different, and the specific preparation process is as follows:

[0162] Prepare 0.4L of 0.2mol / L potassium permanganate solution, heat to 80℃ in a water bath, and stir at 1000rpm; first add 0.2L of 0.1mol / L cobalt nitrate solution and 0.2L of 0.5mol / L cerium nitrate solution, and then add 103.9g of porous carrier γ-Al 2 O 3 (The average particle size is 75 μm, and the carrier morphology is as follows Figure 1 As shown), continue to stir and disperse for 0.5h; continue to add 4 mol / L potassium hydroxide as a co-reactant to adjust the solution pH to 7; after reacting for 2h, filter, wash with water, and dry in a 100°C forced air oven for 8h to obtain a supported cobalt-cerium-manganese trimetallic oxide catalyst. Figure 4 As shown, it can be seen that changing the order of adding the carriers will result in a low and uneven loading of the transition metal oxides.

[0163] Comparative Example 1

[0164] In this comparative example, a non-loaded cobalt-cerium-manganese ternary metal oxide catalyst was prepared, denoted as Co 0.1 Ce 0.5 Mn 0.4 O z , z takes a value of 1.2-2.0, and the specific value is related to the actual valence state of the transition metal element and the vacancies in the material.

[0165] The preparation process is:

[0166] Prepare 0.4L of 0.2mol / L potassium permanganate solution, heat to 80℃ in a water bath, and stir at 500rpm; then add 0.2L of 0.1mol / L cobalt nitrate solution and 0.2L of 0.5mol / L cerium nitrate solution, and continue to add 4mol / L potassium hydroxide as a co-reactant to adjust the solution pH to 7; after reacting for 2h, filter and wash with water several times, and dry in a 100℃ forced air oven for 8h to obtain an unloaded cobalt-cerium-manganese ternary metal oxide catalyst. The morphology is as follows Figure 5It can be seen that the size of the catalyst prepared by the redox precipitation method is basically below 1 μm, in a loose state, and the particle distribution is uniform.

[0167] Comparative Example 2

[0168] In this comparative example, a supported cobalt-cerium-manganese ternary metal oxide catalyst was prepared, which was recorded as 4wt%-Co 0.1 Ce 0.5 Mn 0.4 O z @γ-Al 2 O 3 -C, z is 1.2-2.0, and the specific value is related to the actual valence state of the transition metal element and the vacancy in the material; γ-Al 2 O 3 -C represents commercially available conventional γ-Al 2 O 3 The carrier (average particle size is 75 μm, the carrier morphology is as follows Figure 6 4wt% represents Co 0.1 Ce 0.5 Mn 0.4 O z γ-Al 2 O 3 The mass fraction of -C is 4%.

[0169] The preparation process is the same as in Example 1, except that the carrier type is different. The morphology of the prepared supported cobalt-cerium-manganese ternary metal oxide catalyst is as follows: Figure 7 shown.

[0170] Combination Figure 6 and Figure 7 It can be seen that conventional γ-Al 2 O 3 The carrier is close to a solid state, which is not conducive to the effective loading of transition metal oxides. Only a small amount of catalyst is coated on the carrier, and the loading effect is not good.

[0171] Test Case

[0172] The catalytic decomposition effect of the catalysts prepared in Examples 1-7 and Comparative Examples 1-2 on chicken fat was tested, and the test method was as follows:

[0173] (1) Chicken fat decomposition temperature

[0174] The catalyst was added to the chicken fat and mixed, and then a thermogravimetric analysis (TGA) was performed. The amount of catalyst added was 2 mg relative to 1 mg of chicken fat. The decomposition temperature of the chicken fat was specifically the temperature corresponding to the intersection of the reverse extension lines of the two linear intervals before and after the rapid weight loss of the TGA curve.

[0175] (2) Coating roughness and its effect on chicken fat decomposition

[0176] Sample preparation method: The catalyst and the resin are prepared into a solvent-based coating in a mass ratio of 2:1 with a solid content of 60%; the coating is sprayed on a metal substrate to form a catalyst coating with a dry film thickness of 100 μm after drying to obtain a sample.

[0177] Test method:

[0178] Roughness: measured using a roughness tester.

[0179] Chicken fat decomposition rate %: A high-precision analytical balance (weighing accuracy 0.1 mg) was used to calculate the chicken fat decomposition rate by weighing. The specific method is as follows: weigh the mass M of the sample 0 , chicken oil is added to the surface of the catalytic coating with a micropipette. The amount of chicken oil in a single test is about 0.1g chicken oil / 3g coating. The total mass of the sample and chicken oil is weighed M 1 ; Place the sample with chicken fat in an oven at 280°C for 10 minutes, take out the sample and let it cool to room temperature, and weigh the total mass M of the sample and the remaining chicken fat again. 2 The formula for calculating the chicken fat decomposition rate η (%) is: η = (M 1 -M 2 )*100% / (M 1 -M 0 ).

[0180] The decomposition effects of the catalysts prepared in Examples 1-7 and Comparative Examples 1-2 on chicken fat and the corresponding coating roughness are shown in Table 1.

[0181] Table 1 Decomposition effect of catalyst and coating on chicken fat and coating roughness

[0182]

[0183] As shown in Table 1, the chicken fat decomposition temperature of the supported cobalt-cerium-manganese ternary metal oxide catalysts of Example 1 (loading amount 25wt%) and Example 2 (loading amount 70wt%) is lower, and the chicken fat decomposition rate is as high as 99% (considering a reasonable weighing error, it can be considered that the chicken fat decomposition rate of Example 2 is not substantially different from that of Example 1). It can also be seen that when the loading amount is increased to a certain value, further increasing the loading amount may not significantly improve the catalytic performance. Furthermore, under the condition of meeting the catalytic performance requirements, a solution with a lower loading amount can be selected to reduce the cost (the cost of the transition metal oxide is much higher than that of the carrier).

[0184] It should be noted that, in order to quickly test the catalytic decomposition performance of the catalyst on chicken fat, the amount of the catalyst used in this test example will be obviously excessive. It can be understood that the amount of the catalyst used in the test does not represent the amount of the catalyst used in actual applications. Taking Example 1 as an example, for the chicken fat decomposition rate test, the same sample was tested more than 10 times, and the chicken fat decomposition rate was stabilized at about 99%, and it can be seen that the amount of the catalyst used is obviously excessive. In actual applications, the coating is used for the catalytic decomposition of grease, and the amount of the catalyst used can be controlled within the following range: relative to the decomposition of 1g of grease, wherein the addition of the transition metal oxide is ≤1mg, and the specific addition can be determined according to the actual application requirements to better balance the catalytic effect and cost.

[0185] It can be seen from Examples 3 to 5 that changing the carrier particle size can achieve effective loading of transition metal oxides, but different compositions of transition metal elements will result in obvious differences in catalytic effects.

[0186] It can be seen from Examples 6 and 7 that different stirring rates and the order of adding the porous carriers have significant effects on the loading amount and loading uniformity of the transition metal oxides, and thus affect the catalytic performance. However, in general, due to the use of porous carriers, compared with the unloaded catalyst (Comparative Example 1) and the conventional γ-Al 2 O 3 For the supported catalysts, under the same conditions, the chicken fat decomposition rate of the coating has been significantly improved, reflecting a higher catalytic activity.

[0187] Figure 8 For comparative example 1 ( Figure 8 a) and Example 1 ( Figure 8 b) Photograph of the coating prepared by the prepared catalyst after decomposing chicken fat. It can be seen that the catalyst of Example 1 decomposes the chicken fat more thoroughly, and no residue is visually observed, while the catalyst of Comparative Example 1 decomposes the chicken fat with very obvious oil stains remaining, which is consistent with the test result of the chicken fat decomposition rate.

[0188] Compared with the unloaded transition metal oxide catalyst of Comparative Example 1, Example 1 is to load the transition metal oxide on a porous carrier, wherein the main component is the carrier, so the content of the transition metal oxide in the tested sample is significantly lower, resulting in a relatively higher chicken fat decomposition temperature. However, in terms of catalytic activity, since the transition metal oxide of the embodiment of the present invention is loaded on a porous carrier with a special pore structure, the dispersed specific surface area is increased, and the catalytic effect is more advantageous. Under the same circumstances, the amount of transition metal oxide that needs to be added will be lower.

[0189] (3) Coating surface morphology

[0190] The surface micromorphology of the coatings prepared by using the catalysts prepared in Comparative Example 1 and Example 1 was observed by scanning electron microscopy (SEM). Fig. 9 and Fig.10 shown.

[0191] It can be seen that the catalyst (Co 0.1 Ce 0.5 Mn 0.4 O z ) Due to its small size, during the coating preparation process, the small-sized catalyst is basically completely coated by the resin, resulting in the catalyst's active sites being unable to fully contact the outside world ( Fig. 9 ), so the catalytic performance is poor. The catalyst prepared in Example 1 (25wt%-CoCeMnO x @γ-Al 2 O 3 ) The in-situ reaction on the carrier forms a uniformly dispersed coating. Due to the large size of the carrier, a large number of porous structures can be naturally formed during the preparation of the coating, so that the catalyst is exposed as much as possible. When organic matter such as grease comes into contact with the coating, it will quickly diffuse into the pore structure and come into contact with the catalyst ( Fig.10 ), thus showing excellent catalytic performance.

[0192] It can be understood that in addition to oils and fats, transition metal oxides can also catalyze the decomposition of VOCs, for example, benzene, toluene, xylene, formaldehyde, trimethylamine, methyl mercaptan and other organic substances. Furthermore, compared with unloaded transition metal oxides, the supported transition metal oxide catalyst of this embodiment is also more advantageous in catalyzing the decomposition of VOCs.

[0193] It can be understood that since the supported transition metal oxide catalyst of this embodiment has the advantages of high load capacity of transition metal oxide (up to 70% of the weight of the porous carrier), adjustable load capacity, and good dispersibility of transition metal elements, it has excellent catalytic effect. When applied to coatings and other scenes, it can improve the surface roughness, expose more transition metal oxides, and improve catalytic performance. Furthermore, the supported transition metal oxide catalyst or the coating made thereof can be applied to household appliances, and can effectively decompose grease on the surface of household appliances, or organic matter such as grease and VOCs in the air.

[0194] Specifically, the household appliance may be an oven, an air fryer, a heater, a range hood, a refrigerator, a washing machine or an air purifier, etc.

[0195] The present invention has been described in detail above in conjunction with the embodiments, but the present invention is not limited to the above embodiments, and various changes can be made within the knowledge scope of ordinary technicians in the relevant technical field without departing from the purpose of the present invention.

Claims

1. A supported transition metal oxide catalyst, characterized in that: include: A porous carrier, wherein the porous carrier contains pores with a pore size of 1-50 μm, and the porosity of the porous carrier is not less than 50%; A transition metal oxide is supported on the porous support.

2. The supported transition metal oxide catalyst according to claim 1, characterized in that The porous carrier is selected from at least one of α-Al2O3, γ-Al2O3, SiO2, TiO2, ZrO2, diatomaceous earth and molecular sieve.

3. The supported transition metal oxide catalyst according to claim 1 or 2, characterized in that: The porosity of the porous carrier is 50%-80%; and / or the pore size of the pores of the porous carrier is 1-20 μm; and / or the average particle size of the porous carrier is 20-250 μm.

4. The supported transition metal oxide catalyst according to claim 1, characterized in that In the transition metal oxide, the transition metal element is selected from at least one of iron, cerium, cobalt and manganese; and / or the content of the transition metal oxide is 20%-70% of the mass of the porous carrier.

5. The supported transition metal oxide catalyst according to claim 1, 2 or 4, characterized in that: The chemical formula of the transition metal oxide is Co x Ce y Mn 1-(x+y) O z , where 0.05≤x≤0.6, 0.05≤y≤0.6, 1.0≤z≤2.

0.

6. The method for preparing a supported transition metal oxide catalyst according to any one of claims 1 to 5, characterized in that: Includes steps: The porous carrier is dispersed in a solution containing an oxidant of a transition metal element, and a solution containing a reductant of a transition metal element is added to obtain a first mixed solution, and a redox precipitation reaction is performed; or, The porous carrier is dispersed in a solution containing a reducing agent of a transition metal element, and then a solution containing an oxidizing agent of a transition metal element is added to obtain a second mixed solution, and a redox precipitation reaction is performed.

7. The preparation method according to claim 6, characterized in that: The oxidant includes potassium permanganate or iron salt; the reductant includes at least one of ferrous salt, cerium salt, cobalt salt and manganese salt; wherein the iron salt, ferrous salt, cerium salt, cobalt salt and manganese salt are each independently selected from at least one of sulfate, nitrate, acetate or chloride of the corresponding transition metal element.

8. The preparation method according to claim 6, characterized in that: A co-reactant is also added during the redox precipitation reaction, and the co-reactant is a base.

9. The preparation method according to claim 6, characterized in that: The concentration of the solution containing the oxidizing agent of the transition metal element is 0.02-1.60 mol / L, and / or the concentration of the solution containing the reducing agent of the transition metal element is 0.02-4 mol / L.

10. The preparation method according to claim 6, characterized in that: The temperature of the redox precipitation reaction is 20-100° C.; and / or, the time of the redox precipitation reaction is 1-10 h; and / or, the pH of the redox precipitation reaction is ≥7.

11. Use of the supported transition metal oxide catalyst according to any one of claims 1 to 5 in catalytic decomposition of organic matter.

12. A coating, characterized in that: The raw material for preparing the coating layer includes the supported transition metal oxide catalyst as described in any one of claims 1 to 5.

13. A household appliance, characterized in that: The household appliance contains the supported transition metal oxide catalyst according to any one of claims 1 to 5 or the coating according to claim 12.

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