Manganese-based thermocatalytic coating, preparation method thereof and cooking utensil

Abstract

The invention discloses a manganese-based thermocatalytic coating, a preparation method thereof and a cooking utensil, and belongs to the field of thermocatalytic coatings. The manganese-based thermocatalytic coating comprises a manganese dioxide catalyst and a silicon-based adhesive, the manganese dioxide catalyst has a nano polycrystalline structure, and the nano polycrystalline structure comprises nanoscale crystal particles. The nanoscale crystal particles can provide oxygen vacancies with rich activity, adsorb a large amount of oxygen and provide an oxygen source for oxidative degradation of the coating on oil fume grease, so that the oil fume grease is degraded more thoroughly; the silicon-based thermal catalyst and the manganese dioxide catalyst are compounded to obtain the manganese-based thermal catalytic coating with strong adhesive force and high roughness, so that the manganese-based thermal catalytic coating has relatively strong catalytic activity.

Description

Technical Field

[0001] The present invention relates to the field of thermal catalytic coatings, and particularly to a manganese-based thermal catalytic coating, a preparation method thereof, and a cooking appliance. Background Art

[0002] With the improvement of people's living standards and the change of eating habits, the cooking industry has developed rapidly. However, the oil fumes and grease generated during the cooking process have become an environmental pollution problem that cannot be ignored. These oil fumes and grease will not only have a negative impact on people's health, but also pollute the surrounding environment.

[0003] Traditional oil fume purification technologies include methods such as mechanical filtration, electrostatic deposition, and activated carbon adsorption. These methods can reduce the emission of oil fumes and grease to a certain extent, but there are some disadvantages, such as easy to cause secondary pollution, high operation cost, etc. Therefore, it is particularly important to develop an efficient and environmentally friendly cooking oil fume and oil pollution purification technology. Summary of the Invention

[0004] The main purpose of the present invention is to provide a manganese-based thermal catalytic coating, a preparation method thereof, and a cooking appliance, which can catalytically oxidize and degrade the oil fume and grease pollutants generated during cooking, and solve the technical problems that oil fume and grease pollutants and harmful substances are easily generated during the cooking process, and the cooking appliance is easy to accumulate oil stains and difficult to clean.

[0005] To achieve the above object, the present invention provides a manganese-based thermal catalytic coating, which includes a manganese dioxide catalyst and a silicon-based binder. The manganese dioxide catalyst has a nano-polycrystalline structure, and the nano-polycrystalline structure includes nano-scale crystal grains.

[0006] In some embodiments of the present application, a metal element is doped in the crystal lattice of the nano-polycrystalline structure of the manganese dioxide catalyst, and the metal element includes an alkali metal and / or a noble metal.

[0007] In some embodiments of the present application, the alkali metal includes at least one of potassium, calcium, magnesium, aluminum, zinc, copper, iron, cerium, cobalt, titanium, zirconium, nickel, vanadium, lanthanum, and tungsten;

[0008] and / or, the noble metal includes at least one of gold, platinum, palladium, rhodium, and ruthenium.

[0009] In some embodiments of the present application, the manganese dioxide catalyst in the manganese-based thermal catalytic coating is exposed to the air.

[0010] In some embodiments of the present application, the length range of a single crystal of the crystal grains is 3 nm - 200 nm;

[0011] and / or, the manganese dioxide catalyst has a pore structure;

[0012] And / or, the particle size range of the manganese dioxide catalyst is 70 μm - 150 μm.

[0013] In some embodiments of the present application, the shape of the manganese dioxide catalyst includes flaky, acicular, rod-shaped, strip-shaped, spherical or sea urchin-shaped.

[0014] In some embodiments of the present application, the crystal form of the manganese dioxide catalyst includes at least one of α-MnO 2 , β-MnO 2 , γ-MnO 2 , ε-MnO 2 , δ-MnO 2 , λ-MnO 2 .

[0015] In some embodiments of the present application, the XRD characterization pattern of α-MnO 2 has characteristic diffraction peaks at positions of 12.7 ± 0.3°, 18.0 ± 0.3°, 28.8 ± 0.3°, 37.5 ± 0.3°;

[0016] And / or, the XRD characterization pattern of the β-MnO 2 has characteristic diffraction peaks at positions of 28.6 ± 0.3°, 37.3 ± 0.3°, 56.6 ± 0.3°;

[0017] And / or, the XRD characterization pattern of the γ-MnO 2 has characteristic diffraction peaks at positions of 22.3 ± 0.3°, 37.1 ± 0.3°, 56.4 ± 0.3°;

[0018] And / or, the XRD characterization pattern of the ε-MnO 2 has characteristic diffraction peaks at positions of 37.1 ± 0.3°, 60.1 ± 0.3°;

[0019] And / or, the XRD characterization pattern of the δ-MnO 2 has characteristic diffraction peaks at positions of 12.2 ± 0.3°, 24.7 ± 0.3°, 36.4 ± 0.3°;

[0020] And / or, the XRD characterization pattern of the λ-MnO 2 has characteristic diffraction peaks at positions of 21.9 ± 0.3°, 37.1 ± 0.3°, 56.4 ± 0.3°.

[0021] In some embodiments of the present application, based on 100% of the weight of the manganese-based thermal catalytic coating, the weight percentage of the manganese dioxide catalyst is 30% - 90%.

[0022] In some embodiments of the present application, based on 100% of the weight of the manganese-based thermal catalytic coating, the weight percentage of the manganese dioxide metal catalyst is 50%-70%.

[0023] In some embodiments of the present application, the oxygen atoms in the manganese-based thermal catalytic coating are composed of adsorbed oxygen and bound oxygen. Calculated by the area characterized by XPS (X-ray photoelectron spectroscopy analysis), the adsorbed oxygen accounts for 5%-40% of the oxygen atoms.

[0024] In some embodiments of the present application, the thickness of the manganese-based thermal catalytic coating is 50 μm - 500 μm;

[0025] And / or, the roughness of the manganese-based thermal catalytic coating is 5 μm - 400 μm.

[0026] In some embodiments of the present application, the weight ratio of silicon element in the silicon-based binder to manganese element in the manganese dioxide catalyst is (0.5 - 4):1.

[0027] In some embodiments of the present application, the silicon-based binder includes at least one of an organosilicon binder, an inorganic silicon binder, and an organosilicon-inorganic silicon composite binder.

[0028] In some embodiments of the present application, the manganese-based thermal catalytic coating further includes a carrier.

[0029] In some embodiments of the present application, the carrier includes at least one of alumina, silicon carbide, diatomaceous earth, silica, activated carbon, pumice, zeolite, molecular sieve, nickel oxide, zinc oxide, vanadium oxide, zirconium oxide, cerium oxide, copper oxide, and titanium dioxide.

[0030] In some embodiments of the present application, the weight percentage of the carrier in the manganese-based thermal catalytic coating is less than or equal to 90%.

[0031] To achieve the above object, the present invention further provides a preparation method of a manganese-based thermal catalytic coating, including the following steps:

[0032] Dissolve and mix the manganese dioxide catalyst and the silicon-based binder to obtain a manganese-based thermal catalytic coating material;

[0033] Coat the manganese-based thermal catalytic coating material on the surface of a substrate and cure to obtain the manganese-based thermal catalytic coating.

[0034] In some embodiments of the present application, the manganese-based thermal catalytic coating material is coated on the surface of the substrate by a spin coating method, an electroplating method, a vacuum evaporation method, a dip coating method, or a spraying method.

[0035] In some embodiments of the present application, the curing temperature is 100°C - 400°C.

[0036] In some embodiments of the present application, in the step of obtaining the manganese-based thermal catalytic coating, manganese dioxide catalyst, silicon-based binder and carrier are dissolved and mixed to obtain the manganese-based thermal catalytic coating.

[0037] To achieve the above object, the present invention further provides a cooking appliance, which includes the manganese-based thermal catalytic coating as described above in the present invention.

[0038] In some embodiments of the present application, the manganese-based thermal catalytic coating can be coated on the surface of at least one of the inner cavity, heating device, air inlet and outlet, exhaust duct, fan, and filtration module of the cooking appliance.

[0039] In some embodiments of the present application, the cooking appliance includes an air fryer, a deep fryer, a hood integrated machine, a range hood, an electric rice cooker, an automatic stir-fry machine, a range hood, a griddle, and an automatic barbecue machine.

[0040] Beneficial effects that the present invention can achieve:

[0041] The manganese-based thermal catalytic coating of the present invention can be applied to cooking appliances. With the participation of heat sources and oxygen in the air, it can undergo a catalytic oxidation reaction with the oil fumes and grease generated during the cooking process, degrade the oil fumes and grease into water and carbon dioxide, and at the same time inhibit the generation of harmful substances. The above heat source can be provided by the heat generated during the cooking process, enabling the degradation of cooking oil fumes and grease during the cooking process, reducing the accumulation of oil stains on the cooking appliance after cooking, and making it easier to clean.

[0042] The present invention fixes the manganese dioxide catalyst on the surface of the substrate through a silicon-based binder. Without adding a carrier, a large number of catalytic active sites can be exposed and a manganese-based thermal catalytic coating with high roughness can be formed. This can not only increase the contact area between the catalytic active sites and the oil fumes and grease, but also improve the diffusion rate of the oil fumes and grease on the surface of the coating, thereby improving the oxidation degradation rate and effect of the oil fumes and grease, and completely degrading the oil fumes and grease into carbon dioxide and water.

[0043] The manganese dioxide catalyst in the manganese-based thermal catalytic coating of the present invention has a high content and high activity of oxygen vacancies due to its nano-polycrystalline structure, can adsorb a large amount of oxygen to promote the oxidation degradation of oil fumes and grease. Doping noble metals and / or alkali metals in the crystal lattice of the manganese dioxide catalyst can not only obtain a large number of oxygen vacancies, but also reduce the effective temperature of the coating's catalytic oxidation, enabling the coating to oxidize and degrade oil fumes and grease at a relatively low temperature condition below 100°C.

[0044] The manganese-based thermal catalytic coating of the present invention adds a silicon-based binder, which not only has good adhesiveness and stability, and is not prone to falling off during long-term use, which will affect the catalytic oxidation effect, but also has high-temperature resistance. It is not prone to powdering and falling off and reducing the catalytic oxidation effect even in a high-temperature environment of 800 °C, and has a long service life. BRIEF DESCRIPTION OF THE DRAWINGS

[0045] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following briefly introduces the drawings required for use in the description of the embodiments or the prior art. Obviously, the drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can be obtained based on the structures shown in these drawings.

[0046] Figure 1 It is a schematic cross-sectional view of the manganese-based thermal catalytic coating according to an embodiment of the present invention, wherein 1 is a substrate; 2 is a manganese-based thermal catalytic coating; 21 is a manganese dioxide catalyst; 22 is a silicon-based binder.

[0047] Figures 2 to 3 It is an XRD characterization diagram of the manganese-based thermal catalytic coating according to an embodiment of the present invention.

[0048] Figure 4 It is a morphology diagram of the manganese-based thermal catalytic coating according to an embodiment of the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0049] It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0050] The following will clearly and completely describe the technical solutions in the embodiments of the present invention with reference to the drawings in the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, rather than all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts belong to the scope of protection of the present invention.

[0051] In the present invention, descriptions such as "first" and "second" are only for descriptive purposes and cannot be understood as indicating or implying their relative importance or implicitly indicating the quantity of the indicated technical features. Thus, features defined with "first" and "second" may explicitly or implicitly include at least one of these features. In addition, the technical solutions between various embodiments can be combined with each other, but it must be based on the fact that those of ordinary skill in the art can implement them. When the combination of technical solutions is contradictory or cannot be implemented, it should be considered that such a combination of technical solutions does not exist and is not within the scope of protection required by the present invention.

[0052] The present invention provides a manganese-based thermal catalytic coating, which includes a manganese dioxide catalyst and a silicon-based binder. The manganese dioxide catalyst has a nano-polycrystalline structure, and the nano-polycrystalline structure includes nano-scale crystal grains.

[0053] The manganese-based thermal catalytic coating of the present invention can be applied to cooking utensils. With the participation of a heat source and oxygen in the air, it can undergo a catalytic oxidation reaction with the cooking fumes and grease generated during the cooking process, degrade the cooking fumes and grease into water and carbon dioxide, and at the same time inhibit the generation of harmful substances. The above heat source can be provided by the heat generated during the cooking process, enabling the degradation of cooking fumes and grease during the cooking process, reducing the accumulation of oil stains on the cooking utensils after cooking, and making them easier to clean.

[0054] The nano-polycrystalline structure of the manganese dioxide catalyst includes nano-scale crystal grains, which can be composed of multiple nano-scale crystal grains. The crystal grains can provide oxygen vacancies, and the oxygen vacancies can adsorb oxygen, increasing the content of adsorbed oxygen and providing sufficient oxygen conditions for the oxidative degradation of cooking fumes and grease. Moreover, the nano-scale crystal grains also have a large specific surface area, which can enhance the adsorption of oxygen and prolong the residence time of cooking oil stains on the coating surface, making the degradation of cooking fumes and grease more complete.

[0055] In some embodiments, metal elements can also be doped into the crystal lattice of the nano-polycrystalline structure of the manganese dioxide catalyst. The metal elements include alkali metals and / or noble metals, so as to increase the content of oxygen vacancies in the manganese dioxide catalyst, improve the amount of adsorbed oxygen, facilitate the degradation of cooking fumes and grease, and at the same time reduce the effective temperature of the catalytic oxidation of the coating, enabling the coating to catalytically degrade cooking fumes and grease at a relatively low temperature of 95°C.

[0056] In some embodiments, the temperature for the oxidative degradation of cooking fumes and grease by the manganese-based thermal catalytic coating doped with alkali metals and / or noble metals in the manganese dioxide catalyst is 95°C - 400°C, which can be any temperature value within the range of 95°C - 400°C, such as 95°C, 100°C, 105°C, 110°C, 120°C, 150°C, 200°C, 250°C, 300°C, 400°C, etc. Within the above temperature range, the manganese-based thermal catalytic coating can catalytically oxidize and degrade cooking fumes and grease to form carbon dioxide and water, and the above temperature range basically covers the daily cooking temperature, enabling the oxidative degradation of cooking fumes and grease generated during cooking during the cooking process.

[0057] In some embodiments, the alkali metals include at least one of potassium, calcium, magnesium, aluminum, zinc, copper, iron, cerium, cobalt, titanium, zirconium, nickel, vanadium, lanthanum, and tungsten. The above types of alkali metal elements can reduce the effective temperature of the catalytic oxidation of the manganese-based thermal catalytic coating to 95 °C, and can achieve the oxidative degradation of cooking fume grease under the conditions of 95 °C - 400 °C. Usually, the cooking temperature is also within the range of 95 °C - 400 °C, so that the purpose of catalytic oxidative degradation of the cooking fume grease generated during cooking can be achieved.

[0058] In some embodiments, the noble metals include at least one of gold, platinum, palladium, rhodium, and ruthenium. The above types of noble metal elements can reduce the effective temperature of the catalytic oxidation of the manganese-based thermal catalytic coating to 95 °C, and can achieve the oxidative degradation of cooking fume grease under the conditions of 95 °C - 400 °C. Usually, the cooking temperature is also within the range of 95 °C - 400 °C, so that the purpose of catalytic oxidative degradation of the cooking fume grease generated during cooking can be achieved.

[0059] The silicon-based binder of the present invention can firmly fix the manganese dioxide catalyst on the surface of the manganese-based thermal catalytic coating. The manganese dioxide catalyst in the manganese-based thermal catalytic coating can be exposed to the air, and the oxygen vacancies and catalytic active sites in the manganese dioxide catalyst are also exposed to the air, which can smoothly adsorb oxygen in the air to provide sufficient oxygen source for the catalytic oxidation degradation reaction. At the same time, the catalytic active sites can also be in close contact with the cooking fume grease, making the degradation of the cooking fume grease more complete. Refer to Figure 1 , the manganese-based thermal catalytic coating 2 is coated on the surface of the substrate 1. The silicon-based binder 22 in the manganese-based thermal catalytic coating 2 firmly fixes the manganese dioxide catalyst 21 on the surface of the coating and exposes it to the air.

[0060] In some embodiments, the manganese dioxide catalyst has a pore structure, which can be a microporous structure, a mesoporous structure, etc. The manganese dioxide catalyst with a pore structure has a large specific surface area, which can expose a large number of catalytic active sites and oxygen vacancies to the air, which is beneficial to increasing the content of adsorbed oxygen and strengthening the contact between the cooking fume grease and the catalytic active sites, and promoting the degradation of the cooking fume grease.

[0061] In some embodiments, the pore volume of the pore structure of the manganese dioxide catalyst is 0.1 cm 3 / g - 1.0 cm 3 / g. For example, it can be 0.1 cm 3 / g, 0.2 cm 3 / g, 0.5 cm 3 / g, 0.6 cm 3 / g, 0.7 cm 3 / g, 0.9 cm 3 / g, 1.0 cm 3 / g, etc. 0.1 cm3 / g - 1.0 cm 3 Any pore volume value within the range of / g.

[0062] In some embodiments, the pore diameter range of the pore structure of the manganese dioxide catalyst is 5 nm - 50 nm. For example, it can be any pore diameter value within the range of 5 nm - 50 nm, such as 5 nm, 10 nm, 15 nm, 20 nm, 25 nm, 30 nm, 35 nm, 40 nm, 45 nm, 50 nm, etc.

[0063] The manganese dioxide catalyst with the above pore volume range and pore diameter range has a mesoporous structure. The mesoporous structure is more conducive to increasing the content of adsorbed oxygen in the coating, and can also improve the adhesion effect of the manganese dioxide catalyst on cooking fume grease, prolong the residence time of cooking fume grease on the catalyst surface, and make its degradation more complete.

[0064] In some embodiments, the length range of a single crystal of the crystal particles of the manganese dioxide catalyst is 3 nm - 200 nm. For example, it can be any value within the range of 3 nm - 200 nm, such as 3 nm, 5 nm, 8 nm, 10 nm, 12 nm, 15 nm, 18 nm, 20 nm, 22 nm, 25 nm, 28 nm, 30 nm, 35 nm, 40 nm, 45 nm, 50 nm, 60 nm, 65 nm, 70 nm, 75 nm, 80 nm, 85 nm, 90 nm, 100 nm, 150 nm, 180 nm, 190 nm, 200 nm, etc. Under the conditions of the above range, the manganese dioxide catalyst has a large specific surface area, which can enhance the adsorption of oxygen, provide a relatively sufficient oxygen source for the degradation of cooking fume grease, and can also prolong the residence time of cooking fume grease on the coating surface, making the degradation of cooking fume grease more complete.

[0065] In some embodiments, the particle size range of the manganese dioxide catalyst is 70 μm - 150 μm. For example, it can be any particle size range within the range of 70 μm - 150 μm, such as 70 μm, 80 μm, 90 μm, 100 μm, 110 μm, 120 μm, 130 μm, 140 μm, 150 μm, etc. Under the conditions of the above particle size range, the manganese dioxide catalyst has a large specific surface area, which can not only expose more catalytic active sites, but also is conducive to improving the adsorption effect of oxygen, enhancing the adhesion effect of the coating on cooking fume grease, and prolonging the residence time of cooking fume oil on the catalyst surface.

[0066] In some embodiments, a sieve with 100 meshes to 200 meshes can be selected to screen the manganese dioxide catalyst with the above particle size range.

[0067] In some embodiments, the shape of the manganese dioxide catalyst in the manganese-based thermal catalytic coating includes flake, acicular, rod-shaped, strip-shaped, spherical or sea urchin-shaped. The above-mentioned shapes are more conducive to increasing the specific surface area of the manganese dioxide catalyst, exposing more oxygen vacancies and catalytic active sites, improving the adsorption effect on oxygen, increasing the content of adsorbed oxygen, increasing the contact area between the catalytic active sites and cooking fume grease, and prolonging the residence time of cooking fume grease on the coating surface, so that the cooking fume grease can be degraded more thoroughly.

[0068] In some embodiments, the width of the flake-shaped manganese dioxide catalyst is 10 nm - 100 μm, and the thickness is 2 nm - 1 μm.

[0069] In some embodiments, the width of the acicular manganese dioxide catalyst is 10 nm - 100 μm, and the thickness is 2 nm - 1 μm.

[0070] In some embodiments, the axial length of the rod-shaped or strip-shaped manganese dioxide catalyst is 10 nm - 10 μm, and the radial length is 10 nm - 100 nm.

[0071] In some embodiments, the diameter of the spherical or sea urchin-shaped manganese dioxide catalyst is 200 nm - 800 nm.

[0072] In some embodiments, the crystal form of the manganese dioxide catalyst includes at least one of α-MnO 2 , β-MnO 2 , γ-MnO 2 , ε-MnO 2 , δ-MnO 2 , λ-MnO 2 , where:

[0073] The XRD characterization pattern of α-MnO 2 has characteristic diffraction peaks at positions of 12.7 ± 0.3°, 18.0 ± 0.3°, 28.8 ± 0.3°, and 37.5 ± 0.3°. The morphology of α-MnO 2 is rod-shaped or strip-shaped, has a large specific surface area, exposes more crystal grains, provides more catalytic active sites and high-active oxygen vacancies, enhances the contact between the catalytic active sites and cooking fume grease, and prolongs the residence time of cooking fume grease on the coating surface. At the same time, it provides an abundant oxygen source, makes the cooking fume grease oxidize and degrade more thoroughly, reduces the residual accumulation of cooking fume grease after cooking, and makes the cooking utensils easier to clean.

[0074] The XRD characterization pattern of β-MnO 2 has characteristic diffraction peaks at positions of 28.6 ± 0.3°, 37.3 ± 0.3°, and 56.6 ± 0.3°. 2Its morphology is rod-shaped, with a large specific surface area, exposing more crystal grains, providing more catalytic active sites and high-active oxygen vacancies, enhancing the contact between catalytic active sites and cooking fume grease, and prolonging the residence time of cooking fume grease on the coating surface. At the same time, it provides an abundant oxygen source, making the oxidation and degradation of cooking fume grease more thorough, reducing the residual accumulation of cooking fume grease after cooking, and making the cooking utensils easier to clean.

[0075] γ-MnO 2 The XRD characterization pattern of γ-MnO has characteristic diffraction peaks at positions of 22.3±0.3°, 37.1±0.3°, and 56.4±0.3°. 2 Its morphology is strip-shaped, with a large specific surface area, providing more catalytic active sites and high-active oxygen vacancies, enhancing the contact between catalytic active sites and cooking fume grease, and prolonging the residence time of cooking fume grease on the coating surface. At the same time, it provides an abundant oxygen source, making the oxidation and degradation of cooking fume grease more thorough, reducing the residual accumulation of cooking fume grease after cooking, and making the cooking utensils easier to clean.

[0076] ε-MnO 2 The XRD characterization pattern of ε-MnO has characteristic diffraction peaks at positions of 37.1±0.3° and 60.1±0.3°. 2 Its morphology is spherical, with a large specific surface area, exposing more crystal grains, providing more catalytic active sites and high-active oxygen vacancies, enhancing the contact between catalytic active sites and cooking fume grease, and prolonging the residence time of cooking fume grease on the coating surface. At the same time, it provides an abundant oxygen source, making the oxidation and degradation of cooking fume grease more thorough, reducing the residual accumulation of cooking fume grease after cooking, and making the cooking utensils easier to clean.

[0077] δ-MnO 2 The XRD characterization pattern of δ-MnO has characteristic diffraction peaks at positions of 12.2±0.3°, 24.7±0.3°, and 36.4±0.3°. 2 Its morphology is sea urchin-shaped, with a large specific surface area, exposing more crystal grains, providing more catalytic active sites and high-active oxygen vacancies, enhancing the contact between catalytic active sites and cooking fume grease, and prolonging the residence time of cooking fume grease on the coating surface. At the same time, it provides an abundant oxygen source, making the oxidation and degradation of cooking fume grease more thorough, reducing the residual accumulation of cooking fume grease after cooking, and making the cooking utensils easier to clean.

[0078] λ-MnO 2 The XRD characterization pattern of λ-MnO has characteristic diffraction peaks at positions of 21.9±0.3°, 37.1±0.3°, and 56.4±0.3°. 2Its morphology is leaf-shaped and flaky, with a large specific surface area, exposing more crystal grains, providing more catalytic active sites and high-active oxygen vacancies, enhancing the contact between catalytic active sites and cooking fume grease, and prolonging the residence time of cooking fume grease on the coating surface. At the same time, it provides an abundant oxygen source, enabling the oxidation and degradation of cooking fume grease to be more thorough, reducing the residual accumulation of cooking fume grease after cooking, and making cooking utensils easier to clean.

[0079] In some embodiments, based on 100% of the weight of the manganese-based thermal catalytic coating, the weight percentage of the manganese dioxide catalyst is 30% - 90%, further 50% - 70%. Specifically, it can be any value in the range of 30% - 90% such as 30%, 40%, 50%, 60%, 70%, 80%, 90%, etc. Under the above weight percentage conditions, it is beneficial for the manganese dioxide catalyst to be fully exposed to the air.

[0080] In some embodiments, the oxygen atoms in the manganese dioxide catalyst are composed of adsorbed oxygen and bound oxygen, and the adsorbed oxygen is beneficial to promoting the oxidation and degradation of cooking fume grease. Calculated by the area characterized by XPS (X-ray photoelectron spectroscopy), the adsorbed oxygen accounts for 5% - 40% of the oxygen atoms, and it can be any value in the range of 5% - 40% such as 5%, 10%, 15%, 20%, 25%, 30%, 35%, 40%, etc. The manganese dioxide catalyst of the present invention has a strong adsorption capacity for oxygen, can adsorb a large amount of oxygen for the oxidation and degradation of cooking fume grease, and improves the degradation efficiency of cooking fume grease.

[0081] In some embodiments, the thickness of the manganese-based thermal catalytic coating is 50μm - 500μm, and it can be any value in the range of 50μm - 500μm such as 50μm, 80μm, 100μm, 120μm, 150μm, 200μm, 250μm, 300μm, 350μm, 400μm, 450μm, 480μm, etc. Under the above thickness range conditions, the manganese-based thermal catalytic coating contains a large number of catalytic active sites exposed to the air, which can enhance the degradation of cooking fume grease, and at the same time, it is not easy to have problems such as the adhesion between the coating and the substrate weakening due to the over-thick coating thickness and powder falling off during long-term use.

[0082] In some embodiments, the roughness of the manganese-based thermal catalytic coating is 5 μm - 400 μm, which can be any value within the range of 5 μm - 400 μm, such as 5 μm, 10 μm, 50 μm, 60 μm, 80 μm, 100 μm, 120 μm, 150 μm, 180 μm, 200 μm, 250 μm, 300 μm, 320 μm, 350 μm, 380 μm, 400 μm, etc. Under the above roughness conditions, it is easier to expose a large number of catalytic active sites to the air, and it can enhance the adsorption effect of cooking fume grease and extend its residence time on the coating surface, making the cooking fume grease degrade more thoroughly.

[0083] The present invention selects a silicon-based binder, which has good high-temperature stability and chemical corrosion resistance, and strong bonding force with the substrate. It can cooperate with the manganese dioxide catalyst to firmly fix the manganese dioxide catalyst on the surface of the coating and expose it to the air, enabling the coating to have a good roughness even without adding a carrier.

[0084] In some embodiments, the weight ratio of silicon element in the silicon-based binder to manganese element in the manganese dioxide catalyst is (0.5 - 4):1. Under the above weight ratio conditions, while the silicon-based binder maintains good adhesion, the manganese-based catalytic coating can fully expose the active sites of the catalyst.

[0085] In some embodiments, the silicon-based binder includes at least one of an organosilicon binder, an inorganic silicon binder, and an organosilicon-inorganic silicon composite binder.

[0086] The inorganic silicon binder has the advantages of good heat resistance, chemical corrosion resistance, and high strength, and is inexpensive, but its adhesion is inferior to that of the organosilicon binder; the organosilicon binder has relatively higher adhesion than the inorganic silicon binder, and also has heat resistance and chemical corrosion resistance, and at the same time has electrical insulation properties, but its curing speed is slightly slower and the price is relatively high, because it contains organic solvents and needs to be cured at a higher temperature. The organosilicon-inorganic silicon composite binder is prepared by the sol-gel method from an organosilicon prepolymer, an inorganic silica sol, and a cross-linking agent, and has strong comprehensive performance. It can not only obtain high-temperature stability and chemical corrosion resistance, but also improve the relatively poor adhesion of the inorganic silicon binder and the relatively slow curing speed of the organosilicon binder, and has excellent adhesion, which can firmly fix the manganese dioxide catalyst and expose it to the air, and the formed coating has the advantage of high roughness.

[0087] In some embodiments, the weight ratio of organosilicon to inorganic silicon binder in the organosilicon-inorganic silicon composite binder is 40% - 60%, preferably 50%.

[0088] The manganese-based thermal catalytic coating of the present invention can obtain a coating with high roughness through the compounding of manganese dioxide catalyst and silicon-based catalyst without adding a carrier. However, this does not mean that the solution of the present invention cannot add a carrier. In some embodiments, the manganese-based thermal catalytic coating further includes a carrier, which can improve the roughness of the manganese-based thermal catalytic coating, expose more catalytic active sites of the manganese dioxide catalyst to the air, increase the contact area between the catalytic active sites and cooking fume grease, improve the diffusion rate of cooking fume grease on the coating, thereby improving the catalytic oxidation degradation rate and effect of cooking fume grease, and completely oxidizing and degrading cooking fume grease into carbon dioxide and water.

[0089] In some embodiments, the carrier includes at least one of alumina, silicon carbide, diatomite, silica, activated carbon, pumice, zeolite, molecular sieve, nickel oxide, zinc oxide, vanadium oxide, zirconium oxide, cerium oxide, copper oxide, and titanium dioxide. Carriers of the above types can expose more catalytic active sites of the manganese dioxide catalyst to the air, increase the contact area between the catalytic active sites and cooking fume grease, improve the diffusion rate of cooking fume grease on the coating, thereby improving the catalytic oxidation degradation rate and effect of cooking fume grease, and completely oxidizing and degrading cooking fume grease into carbon dioxide and water.

[0090] In some embodiments, the weight percentage of the carrier in the manganese-based thermal catalytic coating is less than or equal to 90%, and it can be 90%, 80%, 70%, 60%, 50%, 40%, 30%, 20%, 10%, etc.

[0091] The present invention also provides a preparation method of a manganese-based thermal catalytic coating, including the following steps:

[0092] Step S10: Dissolve and mix a manganese dioxide catalyst and a silicon-based binder to obtain a manganese-based thermal catalyst coating material;

[0093] Step S20: Coat the manganese-based thermal catalyst coating material on the surface of a substrate and cure it to obtain a manganese-based thermal catalytic coating.

[0094] In some embodiments, the manganese-based thermal catalyst coating material can be coated on the surface of the substrate by spin coating, electroplating, vacuum evaporation, dip coating, or spraying. The above coating methods are beneficial to obtaining a manganese-based thermal catalytic coating with a relatively high surface flatness, so that it is not easy to fall off or reduce the catalytic oxidation activity of cooking fume grease after long-term use.

[0095] In some embodiments, the curing temperature is 100°C - 400°C. Through the curing operation, the adhesion between the manganese-based thermal catalytic coating and the substrate can be strengthened, and the manganese-based thermal catalytic coating is not easy to fall off or reduce the catalytic oxidation activity of cooking fume grease after long-term use.

[0096] In some embodiments, in the step of obtaining the manganese-based thermal catalytic coating, a manganese dioxide catalyst, a silicon-based binder, and a carrier are dissolved and mixed to obtain the manganese-based thermal catalytic coating. The carrier helps the manganese dioxide catalyst expose more catalytic active sites to the air, increasing the contact area between the catalytic active sites and the cooking fume grease, improving the diffusion rate of the cooking fume grease on the coating, thereby enhancing the catalytic oxidation degradation rate and effect of the cooking fume grease, and completely oxidizing and degrading the cooking fume grease into carbon dioxide and water.

[0097] In some embodiments, the manganese dioxide catalyst, the silicon-based binder, and the carrier can be dissolved and mixed with a solvent. The solvent includes water and alcohols, and the alcohols include ethanol, ethylene glycol, isopropyl alcohol, and propylene glycol. After dissolving and mixing the above-mentioned manganese dioxide catalyst, silicon-based binder, and carrier with the solvent, the formed manganese-based thermal catalytic coating is a suspension.

[0098] The present invention also provides a cooking appliance. The cooking appliance includes the manganese-based thermal catalytic coating as described above in the present invention. Taking some components in the cooking appliance as the base material, the manganese-based thermal catalytic coating is formed by coating on the surface of the base material through the preparation method of the above-mentioned manganese-based thermal catalytic coating.

[0099] The manganese-based thermal catalytic coating can oxidize and degrade cooking fume grease under aerobic and heat source conditions. Therefore, the above-mentioned manganese-based thermal catalytic coating can be formed by coating on the surface of the components in the cooking appliance where cooking fume grease is likely to accumulate. In some embodiments, the manganese-based thermal catalytic coating can be coated on at least one of the surfaces of the inner cavity, heating device, air inlet and outlet, exhaust duct, fan, and filter module of the cooking appliance. Components of the above types are likely to accumulate cooking fume grease and are difficult to clean. Coating the manganese-based thermal catalytic coating on the surface can make the cooking appliance easier to clean.

[0100] In some embodiments, the cooking appliance includes an air fryer, a deep fryer, a hood integrated machine, a range hood, a rice cooker, an automatic stir-fry machine, a range hood, a griddle, and an automatic barbecue machine.

[0101] Using the manganese-based thermal catalytic coating of the present invention to oxidize and degrade cooking fume oil stains for cleaning purposes, compared with the traditional adsorption method, the manganese-based thermal catalytic coating can be reused, has a longer service life, can reduce the cost of replacing consumables, and greatly reduces the use cost. In addition, the preparation process of the manganese-based thermal catalytic coating of the present invention is simple, easy to operate, and has a low cost, and has broad application prospects. During the process of purifying fumes and grease by the manganese-based thermal catalytic coating, the manganese dioxide catalyst can effectively decompose fumes and grease, keep the surface of the cooking appliance free of cleaning, reduce the cleaning cost, and also reduce the environmental pollution caused by cleaning. Therefore, the present invention has important practical significance and application value, can be widely applied in the cooking industry, and contributes to people's health and quality of life.

[0102] In addition, to achieve the above object, the present invention also provides a preparation method of the manganese dioxide catalyst as described above, comprising the following steps:

[0103] Step 1: Mix a reaction solution A containing divalent manganese ions and a solvent to form a mixed solution C;

[0104] Step 2: Make the mixed solution C form a solid precipitate D;

[0105] Step 3: Calcinate the solid precipitate D to obtain the manganese dioxide catalyst.

[0106] In Step 1, the divalent manganese ions are provided by a manganese salt, and the manganese salt can be dissolved in water to obtain the reaction solution A containing manganese ions. The present invention does not limit the type of the above manganese salt. In some embodiments, the manganese salt includes at least one of manganese nitrate, manganese sulfate, manganese chloride, and potassium permanganate. The above types of manganese salts can form divalent manganese ions in a solution state, which is beneficial to subsequently preparing a manganese dioxide catalyst with a nano-polycrystalline structure.

[0107] In Step 1, the solvent is used to dissolve the reaction solution A. In some embodiments, the solvent includes at least one of potassium permanganate, nitric acid, ammonium sulfite, ammonia water, and ethylene glycol. The above solvents are beneficial to helping the reactant solution A form a better-shaped nano-polycrystalline structure during the calcination process, obtaining more oxygen vacancies, and increasing the oxygen adsorption amount of the catalyst.

[0108] In some embodiments, the reaction solution A can be mixed with potassium permanganate and concentrated nitric acid to form the mixed solution C, which is beneficial to obtaining a manganese dioxide catalyst with a crystal form of α-MnO 2 2.

[0109] In some embodiments, the reaction solution A can be mixed with ammonium sulfite and ammonia water, and the pH of the system can be adjusted to be alkaline to form the mixed solution C. In one embodiment, the pH can be 8, 9, 10, 11, etc., which is beneficial to obtaining a crystal form of λ-MnO 2 2.

[0110] In some embodiments, the reaction solution A can be mixed with potassium permanganate to form the mixed solution C, which is beneficial to obtaining a manganese dioxide catalyst with a crystal form of δ-MnO 2 2.

[0111] In some embodiments, potassium permanganate can be dissolved and then added dropwise to the reaction solution A to form the mixed solution C, which is beneficial to obtaining a manganese dioxide catalyst with a crystal form of β-MnO 2 2.

[0112] In some embodiments, the mixing of the reaction solution A and the solvent can be promoted under stirring, and the stirring speed can be 500 rpm - 1500 rpm.

[0113] In Step 2, there is no limitation on the method of forming solid precipitate D from the mixed solution C. When there is a large amount of liquid in the mixed solution C, the drying method can be selected to obtain solid precipitate D. For example, the mixed solution C can be dried at 90°C - 250°C to obtain solid precipitate D. In some embodiments, the drying temperature can be 90°C, 100°C, 120°C, 130°C, 150°C, 160°C, 180°C, 200°C, 230°C, 250°C, etc.

[0114] In some embodiments, when there is less liquid in the mixed solution C, the static method can be selected to make the mixed solution C form solid precipitate D, and the static time can be 12h, 24h, 48h, etc.

[0115] Performing calcination on the solid precipitate D in Step S30 can promote the reaction of divalent manganese ions to form a manganese dioxide catalyst with a nano-polycrystalline structure.

[0116] In some embodiments, the calcination temperature of the precipitate D is 450°C - 650°C, and the calcination time is 2h - 6h. Specifically, the calcination temperature can be any value within the range of 450°C - 650°C, such as 450°C, 500°C, 550°C, 600°C, 650°C, etc.; the calcination time can be any value within the range of 2h - 6h, such as 2h, 3h, 3.5h, 4h, 4.5h, 5h, 5.5h, 6h, etc. Under the above calcination conditions, it can promote the formation of a manganese dioxide catalyst with a nano-polycrystalline structure from ionic reactants, increase the content of oxygen vacancies in the catalyst, and increase the oxygen adsorption capacity.

[0117] The manganese dioxide catalyst obtained by calcination can be in powder form, or in block or granular form, and then processed into powder form later. The powder-form manganese dioxide catalyst is more conducive to being sprayed into a uniform thermal catalytic coating.

[0118] In some embodiments, after performing calcination on the solid precipitate D in Step 3, the following Step 4 is further included: mixing the manganese dioxide catalyst prepared in the above Steps 1 to 3 with an alkali metal source and / or a noble metal source and ball-milling to obtain a manganese dioxide catalyst doped with alkali metal and / or noble metal in the lattice.

[0119] By means of ball milling, the alkali metal elements in the alkali metal source and the noble metal elements in the noble metal source can be doped into the crystal lattice of the manganese dioxide catalyst, and the nano-polycrystalline structure of the manganese dioxide catalyst itself is not damaged. The alkali metal and / or noble metal further improves the catalytic oxidation degradation effect of the manganese dioxide catalyst on cooking fumes and grease, and further reduces the effective temperature of catalytic oxidation degradation, reducing the effective temperature to 95°C, and having a good catalytic oxidation degradation effect at 95°C - 400°C, covering the conventional cooking temperature range, achieving the purpose of catalytically oxidizing and degrading the cooking fumes and oil stains generated during cooking into carbon dioxide and water during cooking, reducing the accumulation of oil stains after cooking, and making the cooking utensils easier to clean.

[0120] In some embodiments, the ball milling time is 6 - 10 h, which can be any time value in 6 - 10 h such as 6 h, 7 h, 8 h, 9 h, 10 h, etc. Within the above ball milling time, the success rate of doping noble metals and / or alkali metals into the crystal lattice of the manganese dioxide catalyst is relatively high, and it is not easy to damage the nano-polycrystalline structure of the manganese dioxide catalyst.

[0121] In some embodiments, the alkali metal source includes at least one of potassium hydroxide, calcium(II) oxide, magnesium(II) oxide, aluminum(III) oxide, zinc(II) oxide, copper(II) oxide, iron(III) oxide, cerium(III) dioxide, cobalt(III) oxide, titanium(IV) dioxide, zirconium acetate, vanadium(IV) oxide, nickel(II) oxide, lanthanum(III) oxide or tungstic acid. The above types of alkali metal sources and manganese dioxide catalysts are easy to introduce alkali metal elements into the crystal lattice of the manganese dioxide catalyst under ball milling conditions to obtain a metal oxide manganese dioxide catalyst.

[0122] In some embodiments, the noble metal source includes at least one of chloroplatinic acid, ammonium tetrachloroaurate(II), palladium(III) chloride, rhodium(III) acetate, ruthenium(III) acetate, silver(II) nitrate. The above types of noble metal sources and manganese dioxide catalysts are easy to introduce alkali metal elements into the crystal lattice of the manganese dioxide catalyst under ball milling conditions to obtain a metal oxide manganese dioxide catalyst. It should be noted that when the metal source includes the above noble metal sources, after ball milling is completed, it can be calcined at 600°C - 900°C to obtain a metal oxide manganese dioxide catalyst.

[0123] The technical solutions of the present invention will be further described in detail below in conjunction with specific embodiments. It should be understood that the following specific embodiments are only used to explain the present invention and are not used to limit the present invention.

[0124] Example 1

[0125] 1. Preparation of manganese dioxide catalyst α-MnO 2

[0126] Step S10: Dissolve the manganese salt in a mixed solution of water and ethylene glycol to form a reaction solution A containing divalent manganese ions. Under the stirring condition of 500 rpm - 1500 rpm, add potassium permanganate and concentrated nitric acid to the reaction solution A to form a mixed solution C.

[0127] Step S20: Place the mixed solution C in an oven and dry it at 90 - 130 °C to obtain a solid precipitate D.

[0128] Step S30: Place the solid precipitate D in a muffle furnace and calcine it at 450 °C - 650 °C to obtain a manganese dioxide catalyst with a crystal form of α - MnO 2 。

[0129] Example 2

[0130] 1. Preparation of manganese dioxide catalyst β - MnO 2

[0131] Step S10: Dissolve manganese salts manganese chloride and manganese sulfate in a mixed solution of ammonium sulfite and concentrated sulfuric acid to form a reaction solution A containing divalent manganese ions. Under the stirring condition of 500 rpm - 1500 rpm, add potassium permanganate and concentrated nitric acid dropwise to the reaction solution A to form a mixed solution C.

[0132] Step S20: Place the mixed solution C in an oven and dry it at 90 - 130 °C to obtain a solid precipitate D.

[0133] Step S30: Place the solid precipitate D in a muffle furnace and calcine it at 450 °C - 650 °C to obtain a manganese dioxide catalyst with a crystal form of β - MnO 2 。

[0134] Example 3

[0135] 1. Preparation of manganese dioxide catalyst γ - MnO 2

[0136] Step S10: Dissolve the manganese salt manganese nitrate in a mixed solution of ammonium sulfite and ammonia water to form a reaction solution A containing divalent manganese ions. Under the stirring condition of 500 rpm - 1500 rpm, add potassium permanganate and concentrated nitric acid to the reaction solution A to form a mixed solution C.

[0137] Step S20: Place the mixed solution C in an oven and dry it at 90 - 130 °C to obtain a solid precipitate D.

[0138] Step S30: Place the solid precipitate D in a muffle furnace and calcine it at 450 °C - 650 °C to obtain a manganese dioxide catalyst with a crystal form of γ - MnO 2 。

[0139] Example 4

[0140] 1. Preparation of manganese dioxide catalyst ε-MnO 2

[0141] Step S10: Dissolve manganese salts, manganese nitrate and manganese acetate in water to form a reaction solution A containing divalent manganese ions. Under the stirring condition of 500 rpm - 1500 rpm, add potassium permanganate to the reaction solution A to form a mixed solution C.

[0142] Step S20: Place the mixed solution C in an oven and dry it at 90 - 130 °C to obtain a solid precipitate D.

[0143] Step S30: Place the solid precipitate D in a muffle furnace and calcine it at 450 °C - 650 °C to obtain a manganese dioxide catalyst with a crystal form of ε-MnO 2 。

[0144] Example 5

[0145] 1. Preparation of manganese dioxide catalyst δ-MnO 2

[0146] Step S10: Dissolve manganese salt, manganese chloride in water to form a reaction solution A containing divalent manganese ions. Under the stirring condition of 500 rpm - 1500 rpm, add potassium permanganate and concentrated nitric acid to the reaction solution A to form a mixed solution C.

[0147] Step S20: Place the mixed solution C in an oven and dry it at 90 - 130 °C to obtain a solid precipitate D1.

[0148] Step S30: Place the solid precipitate D in a muffle furnace and calcine it at 450 °C - 650 °C to obtain a manganese dioxide catalyst with a crystal form of δ-MnO 2 。

[0149] Example 6

[0150] 1. Preparation of manganese dioxide catalyst λ-MnO 2

[0151] Step S10: Dissolve manganese salt, manganese sulfate in water to form a reaction solution A containing divalent manganese ions. Under the stirring condition of 500 rpm - 1500 rpm, add potassium permanganate and concentrated nitric acid to the reaction solution A to form a mixed solution C.

[0152] Step S20: Place the mixed solution C in an oven and dry it at 90 - 130 °C to obtain a solid precipitate D1.

[0153] Step S30: Place the solid precipitate D in a muffle furnace and calcine it at 450°C - 650°C to obtain a manganese dioxide catalyst with a crystal form of λ-MnO 2 .

[0154] 2. Dope metal elements into the crystal lattice of the manganese dioxide catalyst in this example

[0155] Select the λ-MnO obtained in this example 2 and mix it with a noble metal and / or an alkali metal source, and obtain 4 groups of manganese dioxide catalysts doped with metal elements through ball milling. The types and doping amounts of the doped metal elements are shown in Table 2. When the doped metal source includes a noble metal, after ball milling for 6 h - 10 h, continue to calcine it at 600°C - 900°C to obtain a manganese dioxide catalyst doped with metal elements.

[0156] Example 7

[0157] 1. Prepare a composite manganese dioxide catalyst

[0158] Mix 1 g of γ-MnO in Example 3 2 and 1 g of λ-MnO in Example 6 2 uniformly to form a composite manganese dioxide catalyst.

[0159] 2. Dope metal elements into the crystal lattice of the composite manganese dioxide catalyst

[0160] Select the composite manganese dioxide catalyst obtained in this example and mix it with a noble metal and / or an alkali metal source, and obtain a composite manganese dioxide catalyst doped with metal elements through ball milling. The types and doping amounts of the doped metal elements are shown in Table 2. When the doped metal source includes a noble metal, after ball milling for 6 h - 10 h, continue to calcine it at 600°C - 900°C to obtain a composite manganese dioxide catalyst doped with metal elements.

[0161] Application Example 1

[0162] Prepare the corresponding manganese-based thermal catalytic coatings from the various manganese dioxide catalysts obtained in Examples 1 to 7 respectively according to the following preparation methods:

[0163] Step S10: Dissolve the manganese dioxide catalyst and the silicon-based binder with the solvent ethanol to obtain a manganese-based thermal catalytic coating material, and the specific conditions are shown in Table 1;

[0164] Step S20: Spin-coat the manganese-based thermal catalytic coating material in Step S10 on the surface of the substrate stainless steel, and heat and cure it at 400°C - 600°C to obtain a manganese-based thermal catalytic coating with a thickness of 238 μm.

[0165] Performance Test 1

[0166] 1. Morphology Test

[0167] (1) The manganese-based thermal catalytic coating prepared with the manganese dioxide catalyst of Example 3 was characterized by XRD. The characterization diagram is shown in Figures 2 to 3 .

[0168] It can be seen from Figure 2 that there are characteristic diffraction peaks in the XRD characterization pattern at positions of 22.3 ± 0.3°, 37.1 ± 0.3°, and 56.4 ± 0.3°, indicating that the manganese-based thermal catalytic coating in this example contains manganese dioxide catalyst with a crystal form of γ-MnO 2 .

[0169] It can be seen from Figure 3 that after the manganese dioxide catalyst is prepared to form a manganese-based thermal catalytic coating, it still has high oxygen activity, indicating that the catalytic active sites of the manganese dioxide catalyst are not covered by the silicon-based binder and are effectively exposed. The adsorbed oxygen is at 530.5 ± 0.5 eV, and the combined oxygen is at 533.0 ± 0.5 eV, among which the adsorbed oxygen accounts for 15% (area ratio) of the total oxygen element, and the adsorbed oxygen content is relatively high.

[0170] (2) The manganese-based thermal catalytic coating prepared with the manganese dioxide catalyst of Example 3 was characterized by scanning electron microscopy to observe its morphology. The characterization diagram is shown in Figure 4 .

[0171] 2. Stability Test

[0172] Each group of manganese-based thermal catalytic coatings in Application Example 1 was immersed in vegetable oil at 100 °C for 5 minutes, then taken out and immersed in cold water, and repeated 10 times. The area ratio of the coating showing peeling, blistering, and discoloration was checked and judged according to the following criteria:

[0173] Excellent: 0%;

[0174] Good: 0 - 20% (excluding 0%);

[0175] Medium: 20 - 50% (excluding 20%);

[0176] Poor: >50%.

[0177] 3. Adhesion Test

[0178] On the surface of the manganese-based thermal catalytic coating in the application example, "X" lines of the same size and number were drawn with the same force, and then the coating was torn with 3M tape to observe whether the coating peeled off, and judged according to the following criteria:

[0179] Grade 0: The cutting edge is completely smooth and none of the grids peel off;

[0180] Level 1: There is a little paint film peeling off at the cutting intersection, and the affected cross-cutting area shall not be greater than 5%;

[0181] Level 2: There is paint film peeling off at the cutting edge and / or intersection. The affected cutting area is greater than 5%, but less than 15%;

[0182] Level 3: The paint film partially or completely peels off in large pieces along the cutting edge, and / or partially or completely peels off at different parts of the grid. The affected cutting area is greater than 15% and less than 35%;

[0183] Level 4: The paint film peels off in large pieces along the cutting edge and / or partially or completely peels off at some grids. The affected cutting area is greater than 35% and less than 65%;

[0184] Level 5: Peeling off to any degree exceeding Level 4.

[0185] 4. Catalytic efficiency test

[0186] Use a 1-mL pipette to drop a drop of vegetable oil pollutant on the surface of the manganese-based thermal catalytic coating at a constant temperature of 200 °C. Observe the state of the coating surface after 5 minutes, 10 minutes, and 15 minutes respectively. Check whether a film with glossiness is formed. If a film is formed, it means poor catalytic performance. The faster the film disappears, the higher the catalytic efficiency of the coating.

[0187] The test results of Performance Tests 2 to 4 above are shown in Table 1.

[0188] Table 1

[0189]

[0190] As can be seen from Table 1 to Table 2, the adsorbed oxygen content of the manganese-based thermal catalytic coatings prepared from various manganese dioxide catalysts in Examples 1 to 7 is relatively high. The coating has good stability, adhesion to the substrate, and oxidation degradation effect on grease. No film appears on the coating surface within 5 minutes. Moreover, as can be seen from Example 6, the adsorbed oxygen content of the manganese-based thermal catalytic coating prepared from the manganese dioxide catalyst doped with noble metal and / or alkali metal is relatively high.

[0191] Application Example 2

[0192] The α-MnO 2 crystalline manganese dioxide catalyst obtained in Example 1 was used to prepare 13 groups of manganese-based thermal catalytic coatings according to the following preparation methods:

[0193] Step S10: Dissolve the manganese dioxide catalyst, organic-inorganic silicon-based binder, and carrier with solvent ethanol to obtain a manganese-based thermal catalytic coating;

[0194] Step S20: Spin-coat the manganese-based thermal catalytic coating obtained in Step S10 onto the surface of the substrate stainless steel by spin coating, and heat and cure it at 400°C - 600°C to obtain manganese-based thermal catalytic coatings with different thicknesses.

[0195] Performance Test 2

[0196] Catalytic efficiency test: Use a 1-milliliter pipette to drop a drop of vegetable oil pollutant onto the surface of the manganese-based thermal catalytic coating at a constant temperature of 200°C. Observe the state of the coating surface after 5 minutes, 10 minutes, and 15 minutes respectively. Check whether a film with glossiness is formed. If a film is formed, it represents poor catalytic performance. The faster the film disappears, the higher the catalytic efficiency of the coating. The test results are shown in Table 2.

[0197] Table 2

[0198]

[0199] As can be seen from Table 2, with the increase in the coating thickness and roughness, the removal effect of the coating on grease is better. In addition, from Experiment Group 1 to Experiment Group 13, it can be seen that the manganese-based thermal catalytic coating of the present invention can also obtain a very high roughness and exhibit excellent catalytic activity without adding a carrier by adjusting the manganese dioxide catalyst and the silicon-based binder and then cooperating with the preparation process. The coating can rapidly degrade cooking fume grease within 5 minutes without the appearance of a film.

[0200] The above are only the preferred embodiments of the present invention, and do not limit the patent scope of the present invention accordingly. Any equivalent structural or equivalent process transformation made by using the content of the specification and drawings of the present invention, or directly or indirectly applied in other related technical fields, shall be similarly included within the patent protection scope of the present invention.

Claims

1. A manganese-based thermal catalytic coating, characterized in that, the manganese-based thermal catalytic coating comprises a manganese dioxide catalyst and a silicon-based binder, the manganese dioxide catalyst has a nano polycrystalline structure, and the nano polycrystalline structure comprises nano-scale crystal grains.

2. The manganese-based thermal catalytic coating according to claim 1, characterized in that, a metal element is doped in the crystal lattice of the nano polycrystalline structure of the manganese dioxide catalyst, and the metal element comprises an alkali metal and / or a noble metal.

3. The manganese-based thermal catalytic coating according to claim 2, characterized in that, the alkali metal comprises at least one of potassium, calcium, magnesium, aluminum, zinc, copper, iron, cerium, cobalt, titanium, zirconium, nickel, vanadium, lanthanum, tungsten; and / or, the noble metal comprises at least one of gold, platinum, palladium, rhodium, ruthenium.

4. The manganese-based thermal catalytic coating according to claim 1, characterized in that, the manganese dioxide catalyst in the manganese-based thermal catalytic coating is exposed to air.

5. The manganese-based thermal catalytic coating according to claim 1, characterized in that, the length range of a single crystal of the crystal grains is 3 nm - 200 nm; and / or, the manganese dioxide catalyst has a pore structure; and / or, the particle size range of the manganese dioxide catalyst is 70 μm - 150 μm.

6. The manganese-based thermal catalytic coating according to claim 1, characterized in that, the shape of the manganese dioxide catalyst comprises flaky, acicular, rod-shaped, strip-shaped, spherical or sea urchin-shaped.

7. The manganese-based thermal catalytic coating according to claim 1, characterized in that, The crystal forms of the manganese dioxide catalyst include α-MnO 2 , β-MnO 2 , γ-MnO 2 , ε-MnO 2 , δ-MnO 2 , λ-MnO 2 and at least one of them.

8. The manganese-based thermal catalytic coating according to claim 1, characterized in that, based on 100% of the weight of the manganese-based thermal catalytic coating, the weight percentage of the manganese dioxide catalyst is 30% - 90%.

9. The manganese-based thermal catalytic coating according to claim 8, characterized in that, based on 100% of the weight of the manganese-based thermal catalytic coating, the weight percentage of the manganese dioxide metal catalyst is 50% - 70%.

10. The manganese-based thermal catalytic coating according to claim 1, characterized in that, the oxygen atoms in the manganese-based thermal catalytic coating are composed of adsorbed oxygen and bound oxygen, and calculated by the area characterized by XPS, the adsorbed oxygen accounts for 5% - 40% of the oxygen atoms.

11. The manganese-based thermal catalytic coating according to claim 1, characterized in that, the thickness of the manganese-based thermal catalytic coating is 50 μm - 500 μm; and / or, the roughness of the manganese-based thermal catalytic coating is 5 μm - 400 μm.

12. The manganese-based thermal catalytic coating according to claim 1, characterized in that, the weight ratio of the silicon element in the silicon-based binder to the manganese element in the manganese dioxide catalyst is (0.5 - 4):

1.

13. The manganese-based thermal catalytic coating according to claim 1, characterized in that, the silicon-based binder comprises at least one of an organic silicon binder, an inorganic silicon binder, and an organic silicon-inorganic silicon composite binder.

14. The manganese-based thermal catalytic coating according to claim 1, characterized in that, the manganese-based thermal catalytic coating further comprises a carrier.

15. The manganese-based thermal catalytic coating according to claim 14, characterized in that, The carrier includes at least one of alumina, silicon carbide, diatomite, silica, activated carbon, pumice, zeolite, molecular sieve, nickel oxide, zinc oxide, vanadium oxide, zirconium oxide, cerium oxide, copper oxide, and titanium dioxide.

16. The manganese-based thermal catalytic coating according to claim 14, wherein, the weight percentage of the carrier in the manganese-based thermal catalytic coating is less than or equal to 90%.

17. A method for preparing a manganese-based thermal catalytic coating, wherein, it includes the following steps: dissolving and mixing a manganese dioxide catalyst and a silicon-based binder to obtain a manganese-based thermal catalytic coating material; coating the manganese-based thermal catalytic coating material on the surface of a substrate and curing to obtain the manganese-based thermal catalytic coating.

18. The method for preparing a manganese-based thermal catalytic coating according to claim 17, wherein, the manganese-based thermal catalytic coating material is coated on the surface of the substrate by spin coating, electroplating, vacuum evaporation, dip coating or spraying.

19. The method for preparing a manganese-based thermal catalytic coating according to claim 17, wherein, the curing temperature is 100°C - 400°C.

20. The method for preparing a manganese-based thermal catalytic coating according to claim 17, wherein, in the step of obtaining the manganese-based thermal catalytic coating material, the manganese dioxide catalyst, the silicon-based binder and the carrier are dissolved and mixed to obtain the manganese-based thermal catalytic coating material.

21. A cooking appliance, wherein, the cooking appliance includes the manganese-based thermal catalytic coating according to any one of claims 1 to 16.

22. The cooking appliance according to claim 21, wherein, the manganese-based thermal catalytic coating is coated on the surface of at least one of the inner cavity, heating device, air inlet and outlet, exhaust duct, fan, and filtration module of the cooking appliance.

23. The cooking appliance according to claim 22, wherein, the cooking appliance includes an air fryer, a deep fryer, a hood integrated machine, a range hood, a rice cooker, an automatic cooking machine, a range hood, a griddle, and an automatic barbecue machine.

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