Manganese-based catalyst as well as preparation method and application thereof

Abstract

The invention relates to the field of low-temperature plasma catalyst preparation, and discloses a manganese-based catalyst and a preparation method and application thereof. The manganese-based catalyst comprises manganese oxide and an auxiliary active component; the auxiliary active component is selected from one or more than two of Co oxide, Ce oxide, Cu oxide, Ni oxide and Ti oxide; the manganese oxide is in contact with the auxiliary active component to construct a heterogeneous interface; and the grain size of the manganese oxide and the auxiliary active component is 0.5-5 nm. According to the manganese-based catalyst, the degradation efficiency of VOCs can be remarkably improved, the emission amount of NOx and ozone in tail gas can be effectively reduced, and green degradation of VOCs is achieved.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of low-temperature plasma catalyst preparation, in particular to a manganese-based catalyst and a preparation method and application thereof. BACKGROUND

[0002] VOCs is a kind of organic compounds with volatility and can participate in photochemical reaction, which will react under light to form photochemical smog, and is one of the precursors of ozone pollution and PM2.5. Long-term stay in the environment containing volatile organic compounds will increase the possibility of diseases such as cancer. Therefore, reducing the emission of VOCs in industry has extremely important application value.

[0003] Low-temperature plasma technology is widely used in the treatment of volatile organic waste gas (VOCs) in petrochemical, spraying, breeding and municipal sewage treatment fields due to its simple process, on-off operation and low running cost. The main reaction principle of this technology is that under the action of the electric field formed in the gap between the positive and negative electrodes, the outer electrons in the gas molecules can not only have non-elastic collision with VOCs molecules, but also have non-elastic collision with background gas molecules (such as nitrogen, oxygen and water vapor, etc.), generating active groups such as N free radicals, O free radicals and OH free radicals to continue to react with VOCs molecules, and finally mineralize VOCs into CO2 and H2O. However, when low-temperature plasma is used alone to degrade VOCs, many organic intermediate products with certain toxicity, NO x and O3 reaction by-products will be produced, which is easy to cause secondary pollution to the environment.

[0004] Studies have shown that the combination of catalyst and low-temperature plasma technology can effectively inhibit the generation of organic intermediate products and reaction by-products (NO x and O3, etc.), and improve the efficiency of VOCs degradation. According to the placement area of the catalyst, plasma coupling catalysis technology is divided into two types, plasma built-in catalysis and plasma post-catalysis. Plasma built-in catalysis refers to that the catalyst is located in the discharge area of the plasma, which can effectively inhibit the generation of organic intermediate products by increasing the local electric field strength and prolonging the reaction time of VOCs molecules and active particles, and improve the mineralization efficiency of VOCs, but the emission amount of by-products NO x and O3 is large, which is easy to cause secondary pollution; plasma post-catalysis refers to that the catalyst is located outside the plasma electric field area, which can decompose NO x and O3, but the degradation efficiency of organic intermediate products generated by the degradation of VOCs in the plasma area is low, which further leads to low VOCs degradation efficiency.

[0005] Therefore, at present, in the technology of coupling low-temperature plasma technology and catalyst to degrade VOCs, it is temporarily impossible to improve the catalytic degradation efficiency of VOCs while avoiding by-products NOx and O3 emissions, and the catalytic degradation efficiency for VOCs needs to be improved. SUMMARY

[0006] The present application aims to overcome the problems of the prior art, i.e. the degradation efficiency for VOCs needs to be further improved in the process of isothermal plasma synergistic catalysis, and toxic by-products NO x and O3 emissions cannot be avoided in the degradation process, and to provide a manganese-based catalyst and a preparation method and application thereof, which can significantly improve the degradation efficiency for VOCs and also effectively reduce the emissions of NO x and O3 in the tail gas, and realize green degradation of VOCs.

[0007] To achieve the above-mentioned purpose, the present application provides a manganese-based catalyst in one aspect, which comprises manganese oxide and an active component;

[0008] The active component is selected from one or two or more of Co oxide, Ce oxide, Cu oxide, Ni oxide and Ti oxide;

[0009] A heterojunction is formed by the contact between the manganese oxide and the active component;

[0010] The grain size of the manganese oxide and the active component is 0.5-5 nm.

[0011] Preferably, the particle size of the manganese-based catalyst is 10-800 nm.

[0012] Preferably, the manganese oxide contains ɑ-MnO2.

[0013] Preferably, the manganese oxide further contains one or more of MnO, Mn3O4 and Mn2O3.

[0014] Preferably, in the manganese oxide, the content of ɑ-MnO2 is 30-90 wt%.

[0015] Preferably, based on the total weight of the manganese-based catalyst, the content of the manganese oxide is 30-90 wt%, and the content of the active component is 10-70 wt%.

[0016] The present application provides a preparation method of a manganese-based catalyst in a second aspect, which comprises the following steps:

[0017] (1) mixing a manganese source and an active component precursor, and then ball milling to a particle size of 1-20 μm;

[0018] (2) the material obtained in step (1) is transported into a thermal plasma reactor for reaction by using a mixture of oxygen and a protective gas as a carrier gas, and the reacted material is cooled;

[0019] The co-active component precursor is selected from one or more than two of Co source, Ce source, Cu source, Ni source and Ti source.

[0020] The material obtained in step (1) is transported into a thermal plasma reactor for reaction at a feeding rate of 1-100 g / min.

[0021] Preferably, the power of the thermal plasma reactor is 5-100 kW.

[0022] Preferably, the co-active component precursor is selected from one or more than two of Co salt, Ce salt, Cu salt, Ni salt and Ti salt.

[0023] Alternatively, the co-active component precursor is selected from one or more than two of Co element, Ce element, Cu element, Ni element and Ti element.

[0024] Alternatively, the co-active component precursor is selected from one or more than two of Co oxide, Ce oxide, Cu oxide, Ni oxide and Ti oxide.

[0025] Preferably, when the co-active component precursor is selected from one or more than two of Co salt, Ce salt, Cu salt, Ni salt and Ti salt, the volume fraction of oxygen in the carrier gas is 20%-30%.

[0026] Preferably, when the co-active component precursor is selected from one or more than two of Co element, Ce element, Cu element, Ni element and Ti element, the volume fraction of oxygen in the carrier gas is 40%-60%.

[0027] Preferably, when the co-active component precursor is selected from one or more than two of Co oxide, Ce oxide, Cu oxide, Ni oxide and Ti oxide, the volume fraction of oxygen in the carrier gas is 3%-8%.

[0028] Preferably, the flow rate of the carrier gas is 0.1-5 m 3 / h.

[0029] Preferably, in step (2), the reacted material is cooled by using cooling gas and cooling water.

[0030] Preferably, the cooling gas is argon and / or nitrogen.

[0031] Preferably, the flow rate of the cooling gas is 0.1-6 m 3 / h.

[0032] Preferably, the flow rate of the cooling water is 1-100 m 3 / h.

[0033] Preferably, the molar ratio of the amount of the manganese source and the amount of the promoter precursor is 0.4-8.5:1, wherein the molar amount of the manganese source and the molar amount of the promoter precursor are both calculated based on metal elements.

[0034] The third aspect of the present application provides a use of the manganese-based catalyst in degrading VOCs.

[0035] The fourth aspect of the present application provides a method for degrading VOCs, the method comprising: loading the manganese-based catalyst into a plasma reactor, and then introducing VOCs for treatment.

[0036] Preferably, the VOCs are selected from one or more of butane, propane, pentane and acetone;

[0037] Preferably, the concentration of the VOCs is 100-3000 ppm;

[0038] Preferably, the flow rate of the VOCs is >0.5 L / min.

[0039] The manganese-based catalyst of the present application is prepared by using a thermal plasma reactor for reaction, which rearranges the active component manganese oxide and the promoter component of the manganese-based catalyst, constructs abundant heterogeneous interfaces, further promotes the decomposition of ozone through the abundant heterogeneous interfaces in the manganese-based catalyst, further utilizes the hydroxyl radicals generated by the decomposition of ozone to improve the degradation effect on VOCs, thereby improving the degradation efficiency of VOCs and achieving the control of the emission amount of by-products ozone and NO x .

[0040] In addition, the manganese-based catalyst of the present application is prepared by using a thermal plasma reaction, which can accurately control the content of different components in the manganese-based catalyst and also can rearrange atoms at a microscale, so that the prepared manganese-based catalyst is rich in a large number of heterogeneous interfaces, and a manganese-based catalyst with small and uniform particle size can be prepared. In addition, the manganese-based catalyst prepared has small grain size of manganese oxide and promoter component, so that the catalyst has higher catalytic activity, which is further beneficial to improving the degradation efficiency of VOCs. BRIEF DESCRIPTION OF DRAWINGS

[0041] Figure 1 is an HRTEM image of the manganese-based catalyst prepared in Example 1;

[0042] Figure 2is a particle size distribution diagram of the manganese-based catalyst prepared in Example 1;

[0043] Figure 3 This is the particle size distribution diagram of the manganese-based catalyst prepared in Example 3. DETAILED DESCRIPTION

[0044] The following describes the specific embodiments of the present invention in detail with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are only used to illustrate and explain the present invention and are not intended to limit the present invention.

[0045] The endpoints of the ranges and any values ​​disclosed herein are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoints of each range, the endpoints of each range and individual point values, and the individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered to be specifically disclosed herein.

[0046] In the present invention, the manganese-based catalyst comprises manganese oxide and a co-active component; the co-active component is selected from one or more of Co oxide, Ce oxide, Cu oxide, Ni oxide, and Ti oxide. The manganese oxide serves as the primary active component of the manganese-based catalyst, and the co-active component is used to further enhance the catalytic performance of the catalyst.

[0047] In the manganese-based catalyst of the present invention, the close contact between the manganese oxide and the co-active component constructs a large number of heterogeneous interfaces, thereby further decomposing ozone through the large number of heterogeneous interface catalysts present in the manganese-based catalyst. The large number of active hydroxyl radicals generated by the decomposition of ozone further improve the degradation efficiency of VOCs, thereby achieving the degradation of VOCs and controlling the amount of by-product emissions, thereby realizing green treatment of VOCs. In the present invention, the heterogeneous interface refers to the interface portion where different substances or different crystal planes are in contact.

[0048] In the present application, the coupling mode of the manganese-based catalyst and the plasma technology is not limited, i.e. the placement position of the manganese-based catalyst in the plasma reactor is not limited, the coupling mode of the manganese-based catalyst and the plasma technology can be built-in catalysis, i.e. the manganese-based catalyst fills the electric field area of the plasma reactor; the coupling mode of the manganese-based catalyst and the plasma technology can also be post-catalysis, i.e. the manganese-based catalyst is placed outside the electric field area of the plasma reactor. In order to further improve the degradation efficiency of VOCs and better control the by-products NOx and ozone, the coupling mode of the manganese-based catalyst and the plasma technology is preferably built-in catalysis, in which the manganese-based catalyst can generate micro-discharge in the plasma discharge area, thereby increasing the degradation efficiency of VOCs, promoting the decomposition of ozone and the formation of hydroxyl radicals, greatly increasing the number of hydroxyl radicals. As one of the strongest oxidants, the increase of hydroxyl radicals greatly improves the degradation rate and mineralization rate of VOCs, and the 99.9% effective removal of NOx by-products can be achieved by multiple active components, greatly reducing secondary pollution.

[0049] In a preferred embodiment, the auxiliary active component in the manganese-based catalyst is selected from one or more of Co oxide, Ce oxide, Cu oxide, Ni oxide and Ti oxide.

[0050] In a preferred embodiment, the particle size of the manganese-based catalyst is 10-800 nm, preferably 20-500 nm. In the present application, the particle size of the manganese-based catalyst is small and more uniform, which can provide more active sites to improve the catalytic reaction effect.

[0051] In the present application, the grain size of the manganese oxide and the auxiliary active component in the manganese-based catalyst is 0.5-5 nm. In the present application, the grain size of the manganese-based catalyst is small, which is convenient for constructing a large number of heterojunctions in the manganese-based catalyst, thereby further improving the catalytic degradation performance of the catalyst.

[0052] In a preferred embodiment, in order to further improve the degradation rate of VOCs, the manganese oxide contains a-MnO2, which is an essential component of the manganese oxide. Preferably, the manganese oxide can also contain one or more of MnO, Mn3O4 and Mn2O3, for example, the components of the manganese oxide can be a-MnO2, a-MnO2 and MnO, or a-MnO2, MnO and Mn3O4. In the present application, the a-MnO2 contained in the manganese oxide has excellent activity, further improving the decomposition efficiency of ozone, thereby generating more active hydroxyl radicals in the reaction. In this preferred embodiment, by further limiting the crystal form and components of the active component manganese oxide, the catalytic performance of the low-temperature plasma catalyst can be further improved, and the harmless degradation of VOCs can be further achieved.

[0053] In a preferred embodiment, the content of the manganese oxide is 30-90wt%, preferably 30-70wt%, based on the total weight of the manganese-based catalyst; the content of the active component is 10-70wt%, preferably 30-70wt%.

[0054] The second aspect of the present application provides a preparation method of a manganese-based catalyst, which comprises the following steps:

[0055] (1) mixing a manganese source and an active component precursor, and then ball milling to a particle size of 1-20μm;

[0056] (2) using a mixture of oxygen and a protective gas as a carrier gas to transport the material obtained in step (1) to a thermal plasma reactor for reaction, and then cooling the reacted material.

[0057] In the present application, the active component precursor is selected from one or more of Co source, Ce source, Cu source, Ni source and Ti source.

[0058] In a preferred embodiment, the active component precursor is selected from one or more of Co salt, Ce salt, Cu salt, Ni salt and Ti salt; or, the active component precursor is selected from one or more of Co element, Ce element, Cu element, Ni element and Ti element; or, the active component precursor is selected from one or more of Co oxide, Ce oxide, Cu oxide, Ni oxide and Ti oxide. In the present application, the active component precursor can be any of salt, element or metal oxide, and the raw materials for preparation are widely available and simple to obtain.

[0059] In a further preferred embodiment, when the co-activator precursor is selected from one or more of Co monomer, Ce monomer, Cu monomer, Ni monomer and Ti monomer, the second active precursor is limited to a particle size of 1-10 μm and a purity of >99.9%, under which conditions the manganese-based catalyst prepared has a higher content of heterogeneous interfaces, thereby imparting the manganese-based catalyst with more excellent catalytic activity.

[0060] In a specific embodiment, the Co salt, Ce salt, Cu salt, Ni salt and Ti salt are all soluble salts. The Co salt can be Co(NO3)2 and / or CoCl2; the Ce salt can be Ce(NO3)3; the Cu salt can be Cu(NO3)2 or CuCl2; the Ni salt can be Ni(NO3)2 or NiCl2; and the Ti salt can be TiCl4.

[0061] In a specific embodiment, the manganese source can be an oxide of manganese or a soluble manganese salt, such as one or more of MnO2, Mn(NO3)2 and MnCl2.

[0062] In the method described in the present application, the manganese source and the co-activator precursor are first mixed by ball milling, in which the manganese source and the co-activator precursor are reacted by mechanical ball milling to obtain a preliminary reaction product, and then the product is reacted by the thermal plasma arc generated by the thermal plasma reactor to obtain the manganese-based catalyst.

[0063] In a preferred embodiment, the ball milling conditions include a rotation speed of 200-800 rpm / min, preferably 400-700 rpm / min, and a time of 8-72 h, preferably 24-48 h.

[0064] In a specific embodiment, zirconium oxide is used as the milling ball during ball milling, and the weight ratio of zirconium oxide to the ball-milled material is limited to 10-20:1.

[0065] In the present application, the particle size of the material delivered to the thermal plasma reactor directly affects the structure of the final product obtained by reaction, and in order to ensure that the manganese-based catalyst prepared is rich in a large number of heterogeneous interface regions, the particle size of the material after ball milling is limited to 1-20 μm, preferably 1-10 μm.

[0066] In the present application, the thermal plasma reactor is a commonly used reactor in the chemical industry, and the high-frequency (also known as radio frequency) thermal plasma has a high temperature and a large amount of heat, which can heat, melt and evaporate materials, and therefore has been widely used in material processing. A stable thermal plasma arc can be generated by energizing the thermal plasma reactor, and the generated thermal plasma arc has an extremely high temperature (2000-4500K). In the present application, the raw materials are instantaneously gasified by the high temperature of the thermal plasma arc, followed by atomic rearrangement and rapid cooling, so that the manganese-based catalyst prepared contains a variety of oxide components, has a small grain size, and is rich in a large number of heterogeneous interfaces, thereby providing more active sites for catalytic reactions and further improving the degradation efficiency of VOCs.

[0067] In the present application, the manganese-based catalyst is prepared by a specific preparation method, so that the manganese-based catalyst prepared is rich in a large number of heterogeneous interfaces and has a smaller grain size, thereby making the catalytic performance of the manganese-based catalyst more excellent and the activity higher.

[0068] In the present application, the thermal plasma reactor used can be a commonly used thermal plasma reactor in the art, and there is no special limitation on the specific type and structure, and the thermal plasma reactor can be operated according to the common operation method in the art to prepare the manganese-based catalyst.

[0069] In the preferred embodiment, in order to make the catalytic effect of the manganese-based catalyst more excellent, the power of the thermal plasma reactor is controlled to be 5-100kW. Specifically, the power of the thermal plasma reactor is directly related to the temperature of the thermal plasma arc generated thereby, and by controlling the power of the thermal plasma reactor, the temperature during the reaction can be further controlled, thereby ensuring the composition and structure of the catalyst prepared. Specifically, the power of the thermal plasma reactor can be 5kW, 10kW, 20kW, 30kW, 40kW, 50kW, 60kW, 70kW, 80kW, 90kW or 100kW.

[0070] In the specific embodiment, a mixture of oxygen and protective gas is used as the carrier gas, which is mainly used to transport the raw materials to be reacted into the thermal plasma reactor, and the oxygen in the carrier gas can also provide oxygen elements during the preparation of the manganese-based catalyst. The protective gas in the carrier gas can be one or more than two of nitrogen, argon and helium.

[0071] In the present application, the content of oxygen in the carrier gas is adjusted according to the components of the selected co-activator precursor, so that the activity of the prepared manganese-based catalyst is more excellent. Specifically, when the co-activator precursor is selected from one or more of Co salt, Ce salt, Cu salt, Ni salt and Ti salt, the volume fraction of oxygen in the carrier gas is 20-30%; when the co-activator precursor is selected from one or more of Co element, Ce element, Cu element, Ni element and Ti element, the volume fraction of oxygen in the carrier gas is 40%-60%; when the co-activator precursor is selected from one or more of Co oxide, Ce oxide, Cu oxide, Ni oxide and Ti oxide, the volume fraction of oxygen in the carrier gas is 3%-8%.

[0072] In a preferred embodiment, in order to further ensure the catalytic performance of the prepared manganese-based catalyst, the flow rate of the carrier gas is 0.1-5 m 3 / h, preferably 0.5-4 m 3 / h. Specifically, the flow rate of the carrier gas can be 0.1 m 3 / h, 1 m 3 / h, 2 m 3 / h, 3 m 3 / h, 4 m 3 / h, or 5 m 3 / h.

[0073] In the present application, in order to ensure the heterostructure of the prepared manganese-based catalyst, and the particle size of the prepared catalyst, the rate of the material delivered to the hot plasma reactor needs to be controlled, and the feeding rate of the material obtained in step (1) delivered to the hot plasma reactor for reaction is 1-100 g / min, preferably 2-50 g / min. When the feeding rate is too large, it may cause the particle size of the prepared manganese-based catalyst to be too large, resulting in serious agglomeration of the prepared catalyst, thereby reducing its catalytic activity.

[0074] In a specific embodiment, since the hot plasma arc temperature generated in the hot plasma reactor is very high, when the material is delivered to the hot plasma reactor for reaction, the material will be gasified instantaneously, then the rearrangement between the gasified atoms will occur, and then the product will be obtained by rapid cooling. Therefore, the whole reaction occurs very quickly, and the reaction material is also delivered to the material collecting device by the carrier gas. The reaction time in the hot plasma reactor is determined by the flow rate of the carrier gas, and the specific reaction time is not limited herein.

[0075] In a specific embodiment, in step (2), in order to ensure that the particle size of the prepared manganese-based catalyst is smaller and more uniform, the reacted material needs to be cooled extremely quickly.

[0076] In the method of the present invention, in step (2), cooling gas and cooling water are used to cool the reacted material. Specifically, the cooling water cools the reacted material through a coil provided in the thermal plasma reactor. The flow direction, flow area, and flow method of the cooling water and cooling gas are all conventional in the art related to thermal plasma reactors and will not be described in detail here.

[0077] In a preferred embodiment, the cooling gas is argon and / or nitrogen.

[0078] In a specific embodiment, the cooling rate of the reacted material is controlled by controlling the flow rate of the cooling gas and cooling water. In order to further control the cooling rate of the material and thus make the particle size of the prepared manganese-based catalyst smaller and more uniform, the flow rate of the cooling gas is limited to 0.1-6 m 3 / h, preferably 2-6m 3 / h; the cooling water flow rate is 1-100m 3 / h, preferably 10-80m 3 / h.

[0079] In a preferred embodiment, the molar ratio of the manganese source to the co-active component precursor is 0.4-8.5:1, wherein the molar amounts of the manganese source and the co-active component precursor are both calculated as metal elements.

[0080] The present invention further provides a manganese-based catalyst prepared by the above-mentioned preparation method. In the manganese-based catalyst, a large number of heterogeneous interfaces are constructed through close contact between the active component and the co-active component contained in the manganese-based catalyst, thereby further improving the catalytic performance of the manganese-based catalyst.

[0081] The present invention can also provide an application of the above-mentioned manganese-based catalyst in the degradation of VOCs. The manganese-based catalyst described in the present invention has a smaller and more uniform particle size, a larger specific surface area, and is rich in more active sites. In addition, the manganese-based catalyst described in the present invention can significantly improve the decomposition efficiency of ozone, thereby increasing the generation of hydroxyl radicals, further improving the degradation efficiency of VOCs, and significantly reducing the toxic byproduct NO. x emissions to avoid secondary pollution.

[0082] The present invention further provides a method for degrading VOCs, which comprises: loading the manganese-based catalyst into a plasma reactor, and then introducing VOCs for treatment.

[0083] In a specific embodiment, the coupling mode of the low-temperature plasma catalyst and the plasma technology is not limited, and is preferably an internal catalytic coupling, i.e., the manganese-based catalyst is filled in the electric field area of the plasma reactor.

[0084] In the present application, the VOCs are selected from one or more of ethane, butane, propane, pentane, isopentane and acetone.

[0085] In the present application, the manganese-based catalyst can treat VOCs with a higher concentration, and the concentration of the VOCs is 100-3000 ppm.

[0086] In a preferred embodiment, the flow rate of the VOCs is >0.5 L / min, for example, it can be 0.8-1.5 L / min.

[0087] In a specific embodiment, the catalytic temperature of the manganese-based catalyst is 0-350℃. The catalytic temperature specifically refers to the temperature at which the manganese-based catalyst actually exerts catalytic action.

[0088] In a preferred embodiment, the manganese-based catalyst of the present application can also treat VOCs with a higher flow rate when treating VOCs, and has a larger treatment amount and a wider range of industrial applications.

[0089] The manganese-based catalyst of the present application is prepared by using a thermal plasma reactor, and the manganese-based catalyst prepared has a large number of heterojunction regions inside, which further improves the decomposition efficiency of ozone through the heterojunction structure, thereby further improving the generation amount of hydroxyl radicals, further improving the degradation rate of VOCs and NO x , achieving complete degradation of VOCs and effectively controlling the toxic by-products generated by degradation to avoid secondary pollution.

[0090] The present application will be described in detail below through examples, but the protection scope of the present application is not limited thereto.

[0091] The examples are implemented on the premise of the technical solutions of the present application, and detailed implementation modes and specific operation processes are given, but the protection scope of the present application is not limited to the following examples.

[0092] In the following examples, the experimental methods are conventional methods in the art unless otherwise specified. The experimental materials used in the following examples are commercially available unless otherwise specified.

[0093] Example 1

[0094] (1) Mn(NO3)2, Ce(NO3)3and Cu(NO3)2were mixed (molar ratio of Mn(NO3)2, Ce(NO3)3and Cu(NO3)2was 14:1:4), then the mixed material was added into a zirconia ball mill tank, and zirconia grinding balls were added for ball milling (weight ratio of zirconia grinding balls to the mixed material was 10:1), the rotation speed of ball milling was 600 rpm / min, the ball milling time was 24 h, and the particle size of the material obtained by ball milling was 1-5 μm;

[0095] (2) A 10 kW thermal plasma reactor was used for preparation, central gas (argon) was introduced into the thermal plasma device, after the plasma arc was formed, stable operation was carried out for 10 minutes, then a mixture of oxygen and argon was used as carrier gas (volume ratio of oxygen to argon was 20:80), the material obtained in step (1) after ball milling was transported into the thermal plasma reactor for reaction, the flow rate of the carrier gas was 2 m 3 / h, the feeding rate was 20 g / min; the material after reaction was cooled by using cooling gas and cooling water, the cooling gas was argon, the flow rate of the cooling gas was 4 m 3 / h, the flow rate of the cooling water was 50 m 3 / h; after stopping feeding, the arc was extinguished, and a manganese-based catalyst was collected;

[0096] XRF test showed that the content of manganese oxide in the manganese-based catalyst was 70.2 wt%, the content of cerium oxide was 10.1 wt%, and the content of copper oxide was 19.7 wt%;

[0097] (3) The manganese-based catalyst was loaded into a shaft cylinder type low temperature plasma reactor, then 500 ppm of isopentane was introduced for treatment, the gas velocity was 1 L / min, the low temperature plasma energy density was 800 J / L, the manganese-based catalyst was located in the electric field area range in the plasma device, and the catalytic temperature was 100°C.

[0098] Example 2

[0099] (1) Mn(NO3)2, Ce(NO3)3and Cu(NO3)2were mixed (molar ratio of Mn(NO3)2, Ce(NO3)3and Cu(NO3)2was 14:1:4), then the mixed material was added into a zirconia ball mill tank, and zirconia grinding balls were added for ball milling (weight ratio of zirconia grinding balls to the mixed material was 10:1), the rotation speed of ball milling was 600 rpm / min, the ball milling time was 24 h, and the particle size of the material obtained by ball milling was 1-5 μm;

[0100] (2) The 10 kW thermal plasma reactor was used for preparation. Central gas (argon) was introduced into the plasma device. After the plasma arc was formed and stably operated for 10 minutes, the mixture of oxygen and argon was used as the carrier gas (the volume ratio of oxygen to argon was 15:85). The material obtained in step (1) after ball milling was transported into the thermal plasma reactor for reaction. The flow rate of the carrier gas was 2 m 3 / h, and the feeding rate was 10 g / min. The reaction material was cooled by using cooling gas and cooling water. The cooling gas was argon, the flow rate of the cooling gas was 2 m 3 / h, and the flow rate of the cooling water was 50 m 3 / h. After stopping feeding, the arc was extinguished, and the manganese-based catalyst was collected.

[0101] XRF test showed that the content of manganese oxide in the manganese-based catalyst was 49.2 wt%, the content of cerium oxide was 25.3 wt%, and the content of copper oxide was 25.5 wt%.

[0102] (3) The manganese-based catalyst was loaded into the shaft cylinder type low-temperature plasma reactor, and then 200 ppm of pentane was introduced for treatment at a gas velocity of 2 L / min and a low-temperature plasma energy density of 800 J / L. The manganese-based catalyst was located in the electric field range in the plasma device, and the catalytic temperature was 150°C.

[0103] Example 3

[0104] (1) Mn(NO3)2, Ce(NO3)3 and Co(NO3)2 were mixed (the molar ratio of Mn(NO3)2, Ce(NO3)3 and Cu(NO3)2 was 5.8:1:0.7). Then the mixed material was added to a zirconia ball mill tank, and zirconia grinding balls were added for ball milling (the weight ratio of zirconia grinding balls to mixed material was 10:1). The rotation speed of ball milling was 600 rpm / min, and the ball milling time was 36 h. The particle size of the material obtained by ball milling was 1-5 μm.

[0105] (2) The 5 kW thermal plasma reactor was used for preparation. Central gas (argon) was introduced into the plasma device. After the plasma arc was formed and stably operated for 10 minutes, the mixture of oxygen and argon was used as the carrier gas (the volume ratio of oxygen to argon was 18:82). The material obtained in step (1) after ball milling was transported into the thermal plasma reactor for reaction. The flow rate of the carrier gas was 2 m 3 / h, and the feeding rate was 5 g / min. The reaction material was cooled by using cooling gas and cooling water. The cooling gas was argon, the flow rate of the cooling gas was 2 m 3 / h, and the flow rate of the cooling water was 50 m 3 / h. After stopping feeding, the arc was extinguished, and the manganese-based catalyst was collected.

[0106] XRF test shows that the content of manganese oxide in the manganese-based catalyst is 60.4wt%, the content of cerium oxide is 20.1wt%, and the content of cobalt oxide is 19.5wt%;

[0107] (3) The manganese-based catalyst was loaded into the shaft cylinder type low-temperature plasma reactor, then 300 ppm of pentane was introduced for treatment, the gas velocity was 0.5 L / min, the low-temperature plasma energy density was 900 J / L, the manganese-based catalyst was located in the electric field area range in the plasma device, and the catalytic temperature was 150°C.

[0108] Example 4

[0109] (1) Mn(NO3)2, Ce(NO3)3 and Ni(NO3)2 were mixed (the molar ratio of Mn(NO3)2, Ce(NO3)3 and Cu(NO3)2 was 4.3:1:1.6). Then the mixed material was added to a zirconia ball mill jar, and zirconia grinding balls were added for ball milling (the weight ratio of zirconia grinding balls to the mixed material was 10:1), the rotation speed of ball milling was 600 rpm / min, the ball milling time was 36 h, and the particle size of the material obtained by ball milling was 1-5 μm;

[0110] (2) A 100 kW thermal plasma reactor was used for preparation, central gas (argon) was introduced into the plasma device, after the plasma arc was formed and stably operated for 10 minutes, a mixture of oxygen and argon was used as the carrier gas (the volume ratio of oxygen to argon was 10:90), the material obtained by ball milling in step (1) was transported into the thermal plasma reactor for reaction, the flow rate of the carrier gas was 2 m 3 / h, the feeding rate was 5 g / min; the material after reaction was cooled by using cooling gas and cooling water, the cooling gas was argon, the flow rate of the cooling gas was 2 m 3 / h, and the flow rate of the cooling water was 50 m 3 / h; after stopping feeding, the arc was extinguished, and the manganese-based catalyst was collected;

[0111] XRF test shows that the content of manganese oxide in the manganese-based catalyst is 54.5wt%, the content of cerium oxide is 24.7wt%, and the content of nickel oxide is 20.8wt%;

[0112] (3) The manganese-based catalyst was loaded into the shaft cylinder type low-temperature plasma reactor, then 300 ppm of pentane was introduced for treatment, the gas velocity was 0.5 L / min, the low-temperature plasma energy density was 900 J / L, the manganese-based catalyst was located in the electric field area range in the plasma device, and the catalytic temperature was 150°C.

[0113] Example 5

[0114] (1) MnO2, CeO2and NiO were mixed (molar ratio of Mn(NO3)2, CeO2and NiO was 50:30:20). Then the mixed material was added into a zirconia ball mill tank and zirconia grinding balls were added for ball milling (weight ratio of zirconia grinding balls to the mixed material was 10:1), the rotation speed of ball milling was 600 rpm / min, the ball milling time was 48 h, and the particle size of the material obtained by ball milling was 1-5 μm;

[0115] (2) A 100 kW thermal plasma reactor was used for preparation, central gas (argon) was introduced into the plasma device, after the plasma arc was formed and stably operated for 10 minutes, a mixture of oxygen and argon was used as carrier gas (volume ratio of oxygen to argon was 5:95), the material obtained by ball milling in step (1) was transported into the thermal plasma reactor for reaction, the flow rate of the carrier gas was 3 m 3 / h, the feeding rate was 5 g / min; the material after reaction was cooled by using cooling gas and cooling water, the cooling gas was argon, the flow rate of the cooling gas was 4 m 3 / h, and the flow rate of the cooling water was 50 m 3 / h; after stopping feeding, the arc was extinguished, and a manganese-based catalyst was collected;

[0116] XRF test showed that the content of manganese oxide in the manganese-based catalyst was 55.5 wt%, the content of cerium oxide was 24.3 wt%, and the content of nickel oxide was 20.2 wt%;

[0117] (3) The low-temperature plasma catalyst was loaded into a shaft cylinder type low-temperature plasma reactor, then 400 ppm of pentane was introduced for treatment, the gas velocity was 0.25 L / min, the low-temperature plasma energy density was 700 J / L, the manganese-based catalyst was located in the electric field range in the plasma device, and the catalytic temperature was 170°C.

[0118] Example 6

[0119] (1) Mn(NO3)2, Ce(NO3)3and Cu(NO3)2were mixed (molar ratio of Mn(NO3)2, Ce(NO3)3and Cu(NO3)2was 2.6:1:2.1). Then the mixed material was added into a zirconia ball mill tank and zirconia grinding balls were added for ball milling (weight ratio of zirconia grinding balls to the mixed material was 10:1), the rotation speed of ball milling was 500 rpm / min, the ball milling time was 36 h, and the particle size of the material obtained by ball milling was 1-5 μm;

[0120] (2) The 10 kW thermal plasma reactor was used for preparation. Central gas (argon) was introduced into the plasma device. After the plasma arc was formed and stably operated for 10 minutes, the mixture of oxygen and argon was used as the carrier gas (the volume ratio of oxygen to argon was 20:80). The material obtained in step (1) after ball milling was transported into the thermal plasma reactor for reaction. The flow rate of the carrier gas was 2 m 3 / h, and the feeding rate was 20 g / min. The reaction material was cooled by using cooling gas and cooling water. The cooling gas was argon, the flow rate of the cooling gas was 2 m 3 / h, and the flow rate of the cooling water was 50 m 3 / h. After stopping feeding, the arc was extinguished, and the manganese-based catalyst was collected.

[0121] XRF test showed that the content of manganese oxide in the manganese-based catalyst was 39.6 wt%, the content of cerium oxide was 30.2 wt%, and the content of copper oxide was 30.2 wt%.

[0122] (3) The manganese-based catalyst was loaded into the shaft cylinder type low-temperature plasma reactor, and then 800 ppm of pentane was introduced for treatment at a gas velocity of 0.5 L / min and a low-temperature plasma energy density of 1000 J / L. The manganese-based catalyst was located in the electric field range of the plasma device, and the catalytic temperature was 180°C.

[0123] Example 7

[0124] (1) MnO2, CeO2 and Co3O4 were mixed (the molar ratio of MnO2, CeO2 and Co3O4 was 13.8:1:4.2). Then the mixed material was added to a zirconia ball mill tank, and zirconia grinding balls were added for ball milling (the weight ratio of zirconia grinding balls to mixed material was 10:1). The rotation speed of ball milling was 600 rpm / min, and the ball milling time was 36 h. The particle size of the material obtained by ball milling was 1-5 μm.

[0125] (2) The 5 kW thermal plasma reactor was used for preparation. Central gas (argon) was introduced into the plasma device. After the plasma arc was formed and stably operated for 10 minutes, the mixture of oxygen and argon was used as the carrier gas (the volume ratio of oxygen to argon was 8:92). The material obtained in step (1) after ball milling was transported into the thermal plasma reactor for reaction. The flow rate of the carrier gas was 2 m 3 / h, and the feeding rate was 5 g / min. The reaction material was cooled by using cooling gas and cooling water. The cooling gas was argon, the flow rate of the cooling gas was 2 m 3 / h, and the flow rate of the cooling water was 50 m 3 / h. After stopping feeding, the arc was extinguished, and the manganese-based catalyst was collected.

[0126] XRF test shows that the content of manganese oxide in the manganese-based catalyst is 69.7wt%, the content of cerium oxide is 9.7wt%, and the content of cobalt oxide is 20.6wt%;

[0127] (3) The manganese-based catalyst was loaded into the shaft cylinder type low-temperature plasma reactor, then 500 ppm of pentane was introduced for treatment, the gas velocity was 0.5 L / min, the low-temperature plasma energy density was 900 J / L, the manganese-based catalyst was located in the electric field area range in the plasma device, and the catalytic temperature was 180°C.

[0128] Example 8

[0129] (1) MnO2, NiO and Co3O4 were mixed (the molar ratio of MnO2, NiO and Co3O4 was 3.7:1.6:1). Then the mixed material was added to a zirconia ball mill tank, and zirconia grinding balls were added for ball milling (the weight ratio of zirconia grinding balls to mixed material was 10:1), the rotation speed of ball milling was 600 rpm / min, the ball milling time was 36 h, and the particle size of the material obtained by ball milling was 1-5 μm;

[0130] (2) A 5 kW thermal plasma reactor was used for preparation, central gas (argon) was introduced into the plasma device, after the plasma arc was formed and stably operated for 10 minutes, a mixture of oxygen and argon was used as the carrier gas (the volume ratio of oxygen to argon was 4:96), the material obtained by ball milling in step (1) was transported into the thermal plasma reactor for reaction, the flow rate of the carrier gas was 2 m 3 / h, the feeding rate was 5 g / min; the material after reaction was cooled by using cooling gas and cooling water, the cooling gas was argon, the flow rate of the cooling gas was 2 m 3 / h, and the flow rate of the cooling water was 50 m 3 / h; after stopping feeding, the arc was extinguished, and the manganese-based catalyst was collected;

[0131] XRF test shows that the content of manganese oxide in the manganese-based catalyst is 59.6g%, the content of nickel oxide is 25.1wt%, and the content of cobalt oxide is 15.3wt%;

[0132] (3) The manganese-based catalyst was loaded into the shaft cylinder type low-temperature plasma reactor, then 500 ppm of pentane was introduced for treatment, the gas velocity was 0.5 L / min, the low-temperature plasma energy density was 900 J / L, the manganese-based catalyst was located in the electric field area range in the plasma device, and the catalytic temperature was 180°C.

[0133] Example 9

[0134] (1) Mix the elemental Mn, elemental Ni and elemental Cu (molar ratio of Mn, Ni and Cu is 5.4:1.1:1). Then put the mixed material into a zirconia ball mill tank and add zirconia grinding balls for ball milling (weight ratio of zirconia grinding balls to the mixed material is 10:1), the rotation speed of ball milling is 600 rpm / min, the ball milling time is 36 h, and the particle size of the material obtained by ball milling is 1-5 μm;

[0135] (2) Use a 5 kW thermal plasma reactor for preparation, introduce central gas (argon) into the plasma device, after the plasma arc is formed, stabilize the operation for 10 minutes, use a mixture of oxygen and argon as the carrier gas (volume ratio of oxygen to argon is 60:40), and then put the material obtained by ball milling in step (1) into the thermal plasma reactor for reaction, the flow rate of the carrier gas is 2 m 3 / h, the feeding rate is 5 g / min; use cooling gas and cooling water to cool the material after reaction, the cooling gas is argon, the flow rate of the cooling gas is 2 m 3 / h, and the flow rate of the cooling water is 50 m 3 / h; stop feeding and extinguish the arc, and collect the manganese-based catalyst;

[0136] XRF test shows that the content of manganese oxide in the manganese-based catalyst is 73.2 wt%, the content of nickel oxide is 14.3 wt%, and the content of copper oxide is 12.5 wt%;

[0137] (3) Put the manganese-based catalyst into the shaft cylinder type low-temperature plasma reactor, then introduce 800 ppm of pentane for treatment, the gas velocity is 0.5 L / min, the low-temperature plasma energy density is 900 J / L, the manganese-based catalyst is located in the electric field range of the plasma device, and the catalytic temperature is 180°C.

[0138] Example 10

[0139] (1) Mix the elemental Mn, elemental Co and elemental Cu (molar ratio of Mn, Co and Cu is 3.1:1.3:1). Then put the mixed material into a zirconia ball mill tank and add zirconia grinding balls for ball milling (weight ratio of zirconia grinding balls to the mixed material is 10:1), the rotation speed of ball milling is 600 rpm / min, the ball milling time is 36 h, and the particle size of the material obtained by ball milling is 1-5 μm;

[0140] (2) The 5 kW thermal plasma reactor was used for preparation. Central gas (argon) was introduced into the plasma device. After the plasma arc was formed and stably operated for 10 minutes, the mixture of oxygen and argon was used as the carrier gas (the volume ratio of oxygen to argon was 55:45). The material obtained in step (1) after ball milling was transported into the thermal plasma reactor for reaction. The flow rate of the carrier gas was 2 m 3 / h, and the feeding rate was 10 g / min. The material after reaction was cooled by using cooling gas and cooling water. The cooling gas was argon, and the flow rate of the cooling gas was 2 m 3 / h. The flow rate of the cooling water was 50 m 3 / h. After stopping feeding, the arc was extinguished, and the manganese-based catalyst was collected.

[0141] XRF test showed that the content of manganese oxide in the manganese-based catalyst was 59.5 wt%, the content of cobalt oxide was 23.3 wt%, and the content of copper oxide was 17.2 wt%.

[0142] (3) The manganese-based catalyst was loaded into the shaft cylinder type low-temperature plasma reactor, and then 1000 ppm of pentane was introduced for treatment at a gas velocity of 1 L / min and a low-temperature plasma energy density of 800 J / L. The manganese-based catalyst was located in the electric field range in the plasma device, and the catalytic temperature was 180°C.

[0143] Comparative Example 1

[0144] The method of Example 1 was followed, except that Ce(NO3)3 and Cu(NO3)2 were not added for preparation.

[0145] Comparative Example 2

[0146] The manganese-based catalyst was prepared by a hydrothermal method, and the specific process was as follows:

[0147] Mn(NO3)2, Ce(NO3)3 and Cu(NO3)2 were mixed (the molar ratio of Mn(NO3)2, Ce(NO3)3 and Cu(NO3)2 was 13.1:1:4.2), dissolved in 300 mL of distilled water, magnetically stirred for 0.5 h, poured into a reaction kettle, sealed, and placed in a water bath at 150°C for hydrothermal reaction for 6 h. After the reaction was completed, the solid product was washed with distilled water and anhydrous ethanol in sequence, centrifuged at 6000 r / min for 5 min using a high-speed centrifuge, and dried at 70°C to obtain the final product.

[0148] Comparative Example 3

[0149] The method of Example 1 was followed, except that the rotation speed of ball milling was 100 rpm / min, the ball milling time was 2 h, and the particle size of the material after ball milling was 50-60 microns.

[0150] Comparative Example 4

[0151] The method according to Example 1 was carried out, except that the feed rate of the thermal plasma reactor was 120 g / min.

[0152] Test Example 1

[0153] The HRTEM image (high resolution transmission electron microscope image) of the manganese-based catalyst prepared in Example 1 was tested by TEM, and the grain size of the manganese-based catalyst was observed according to the tested HRTEM.

[0154] According to the results of Figure 1 It can be seen that there are a large number of heterogeneous interfaces in the manganese-based catalyst, and the grain size is small, about 0.5-3 nm.

[0155] Examples 2-10 are similar to the preparation principle of Example 1, so there are also heterogeneous interfaces in the manganese-based catalyst prepared in Examples 2-10, and the grain size is small, about 0.5-3 nm.

[0156] Test Example 2

[0157] The particle size of the manganese-based catalyst prepared in Example 1 and Example 3 was tested by Malvern particle size analyzer, and the particle size distribution graphs obtained by testing are shown in Figure 2 and Figure 3 .

[0158] From the results of Figure 2 and Figure 3 , it can be seen that the particle size of the manganese-based catalyst according to the present application is small, mainly between 60-200 nm, and the particle size distribution is relatively uniform.

[0159] Test Example 3

[0160] The degradation rate of VOCs of the low-temperature plasma catalyst prepared in Examples 1-10 and Comparative Examples 1-4 was tested, and the concentration of O3 and NO x in the tail gas was also tested.

[0161] Test method: Agilent 8890B gas chromatograph was used to determine the content of VOCs in the degraded gas, double hydrogen flame ionization detector was configured, and the degradation rate of VOCs was calculated according to the formula: (M 降解前气体中vocs的浓度 -M 降解后气体中vocs的浓度 ) ÷ M 降解前气体中vocs的浓度 × 100%, and the results are shown in Table 1.

[0162] A gas analyzer (model Antaris IGS) was used to analyze NO xThe concentrations are shown in Table 1.

[0163] The 106-M ozone analyzer from the American 2B company was used to detect the changes in the O3 concentration of the treated exhaust gas. The results are shown in Table 1.

[0164] Table 1

[0165] Example No. VOCs degradation rate / % Concentration of O3 in exhaust gas / ppm Concentration of NO in exhaust gas / ppm x ​ Example 1 99.7 0.11 1.5 Example 2 99.1 0.17 1.7 Example 3 99.2 0.13 1.6 Example 4 96.9 0.15 2.1 Example 5 96.7 0.16 2.3 Example 6 98.5 0.17 1.8 Example 7 98.3 0.24 1.8 Example 8 99.1 0.16 1.4 Example 9 99.5 0.08 1.1 Example 10 99.8 0.06 1.0 Comparative Example 1 80.1 0.97 56.7 Comparative Example 2 87.4 1.45 49.2 Comparative Example 3 91.5 0.86 12.5 Comparative Example 4 85.3 0.36 7.9

[0166] The results in Table 1 show that the manganese-based catalyst of the present invention can significantly improve the removal rate of pentane and significantly reduce ozone and NO in the tail gas. x concentration, reducing the toxic byproducts ozone and NO x emissions, achieving harmless treatment of VOCs.

[0167] The preferred embodiments of the present invention have been described in detail above, but the present invention is not limited thereto. Within the technical concept of the present invention, various simple variations of the technical solution of the present invention may be made, including combining the various technical features in any other appropriate manner. These simple variations and combinations should also be regarded as disclosed in the present invention and fall within the scope of protection of the present invention.

Claims

1. A manganese-based catalyst, characterized in that The manganese-based catalyst comprises manganese oxide and a co-active component; The auxiliary active component is selected from one or more of Co oxide, Ce oxide, Cu oxide, Ni oxide and Ti oxide; The manganese oxide and the co-active component construct a heterogeneous interface at the contact interface; The crystal size of the manganese oxide and the auxiliary active component is 0.5-5 nm.

2. The manganese-based catalyst according to claim 1, characterized in that The particle size of the manganese-based catalyst is 10-800 nm.

3. The manganese-based catalyst according to claim 1 or 2, characterized in that The manganese oxide contains ɑ-MnO2; Preferably, the manganese oxide further contains one or more of MnO, Mn3O4 and Mn2O3; Preferably, in the manganese oxide, the content of α-MnO2 is 30-90 wt%.

4. The manganese-based catalyst according to claim 1 or 2, characterized in that Based on the total weight of the manganese-based catalyst, the content of the manganese oxide is 30-90 wt%, and the content of the co-active component is 10-70 wt%.

5. A method for preparing a manganese-based catalyst, characterized in that: The preparation method comprises the following steps: (1) mixing a manganese source and a precursor of a co-active component, and then ball milling the mixture to a particle size of 1-20 μm; (2) using a mixture of oxygen and protective gas as a carrier gas, transporting the material obtained in step (1) to a thermal plasma reactor for reaction, and cooling the reacted material; The co-active component precursor is selected from one or more of a Co source, a Ce source, a Cu source, a Ni source and a Ti source; The material obtained in step (1) is transported to the thermal plasma reactor for reaction at a feeding rate of 1-100 g / min.

6. The method for preparing a manganese-based catalyst according to claim 5, characterized in that: The power of the thermal plasma reactor is 5-100 kW.

7. The method for preparing a manganese-based catalyst according to claim 5, characterized in that: The co-active component precursor is selected from one or more of Co salt, Ce salt, Cu salt, Ni salt and Ti salt; Or, the co-active component precursor is selected from one or more of Co, Ce, Cu, Ni and Ti; Alternatively, the co-active component precursor is selected from one or more of Co oxide, Ce oxide, Cu oxide, Ni oxide and Ti oxide.

8. The method for preparing a manganese-based catalyst according to claim 7, wherein: When the co-active component precursor is selected from one or more of Co salt, Ce salt, Cu salt, Ni salt and Ti salt, the volume fraction of oxygen in the carrier gas is 10%-20%; Preferably, when the co-active component precursor is selected from one or more of Co, Ce, Cu, Ni and Ti, the volume fraction of oxygen in the carrier gas is 40%-60%; Preferably, when the co-active component precursor is selected from one or more of Co oxide, Ce oxide, Cu oxide, Ni oxide and Ti oxide, the volume fraction of oxygen in the carrier gas is 3%-8%.

9. The method for preparing a manganese-based catalyst according to claim 5, characterized in that: The flow rate of the carrier gas is 0.1-5m 3 / h.

10. The method for preparing a manganese-based catalyst according to claim 5, characterized in that: In step (2), the reacted material is cooled using cooling air and cooling water; Preferably, the cooling gas is argon and / or nitrogen; Preferably, the flow rate of the cooling gas is 0.1-6m 3 / h; Preferably, the flow rate of the cooling water is 1-100m 3 / h.

11. The method for preparing a manganese-based catalyst according to claim 5 or 8, characterized in that: The molar ratio of the manganese source to the co-active component precursor is 0.4-8.5:1, wherein the molar amounts of the manganese source and the co-active component precursor are both calculated as metal elements.

12. The manganese-based catalyst prepared according to the method for preparing a manganese-based catalyst according to any one of claims 5 to 11.

13. A method for degrading VOCs, characterized in that: The method comprises: loading a manganese-based catalyst into a plasma reactor, and then introducing VOCs for treatment; The low-temperature plasma catalyst is the manganese-based catalyst according to claims 1-5 and claim 12.

14. The method for degrading VOCs according to claim 13, characterized in that: The VOCs are selected from one or more of ethane, butane, propane, pentane, isopentane and acetone; Preferably, the concentration of the VOCs is 100-3000 ppm; Preferably, the flow rate of the VOCs is >0.5 L / min.

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