Nickel-based supported catalyst, preparation method and application thereof, and carbon dioxide methanation method

Abstract

The invention provides a nickel-based supported catalyst, a preparation method and application thereof, and a carbon dioxide methanation method, and belongs to the technical field of catalysts. The nickel-based supported catalyst provided by the invention comprises a carrier and nickel oxide supported on the surface and in pore channels of the carrier, the carrier comprises carbonate and / or citrate. The carbonate and / or citrate are / is used as the carrier, the nickel-based supported catalyst is synthesized by adopting a solution combustion method, the nickel-based supported catalyst has larger specific surface area and smaller particle size, the nickel oxide and the carrier have a stronger mutual combination effect, the nickel-based supported catalyst has excellent stability, and CO2 methanation can be catalyzed for a long time under a low-temperature condition. The nickel-based supported catalyst is combined with the low-temperature plasma, so that CO2 methanation can be catalyzed at normal temperature and normal pressure, and the catalyst has high CO2 conversion rate and CH4 selectivity.

Description

Technical Field

[0001] The invention belongs to the technical field of catalysts, and in particular relates to a nickel-based supported catalyst, a preparation method and application thereof, and a method for methanating carbon dioxide. Background Art

[0002] Global climate change has become one of the major challenges facing society today. The increase in greenhouse gas emissions is the main cause of global warming. As one of the main greenhouse gases, the increasing concentration of carbon dioxide (CO2) has attracted widespread attention. The carbon dioxide methanation reaction can convert CO2 into usable methane (CO2+4H2→CH4+2H2O) and provides a potential solution for the utilization of renewable energy.

[0003] Developing an efficient catalyst is the core of CO2 methanation. At present, the catalysts mainly studied in China include two types: those with precious metals (Pd, Pt, Ru) as active centers and those with non-precious metals (Co, Ni) as active centers. Although precious metal catalysts can have high activity, they have defects such as high cost and scarce resources. However, non-precious metal nickel-based catalysts are widely used in the process of catalytic CO2 methanation due to their advantages such as low cost, good catalytic activity and adjustability.

[0004] For example, the prior art discloses a reverse Ni / CeO2 catalyst. Although the catalyst catalyzes CO2 methanation at 300°C with a CO2 conversion rate of up to 93.7% and a CH4 selectivity of up to 100%, the CO2 conversion rate of the catalyst at 200°C is ≤5.8%, and the catalyst has the defect of poor low-temperature catalytic activity. Summary of the invention

[0005] The purpose of the present invention is to provide a nickel-based supported catalyst, a preparation method and application thereof, and a method for methanation of carbon dioxide. The nickel-based supported catalyst provided by the present invention is combined with low-temperature plasma to achieve catalytic CO2 methanation at room temperature and pressure, has excellent low-temperature catalytic activity, and has a high CO2 conversion rate and CH4 selectivity.

[0006] In order to achieve the purpose of the present invention, the present invention provides the following technical solutions:

[0007] A nickel-based supported catalyst, comprising a carrier and nickel oxide supported on the surface and in the pores of the carrier;

[0008] The carrier includes carbonate and / or citrate.

[0009] Preferably, the carbonate comprises one or more of calcium carbonate, potassium carbonate and magnesium carbonate;

[0010] The citrate includes one or more of sodium citrate, calcium citrate and potassium citrate.

[0011] Preferably, the loading amount of the nickel oxide is 2-15 wt %.

[0012] The present invention also provides a method for preparing the nickel-based supported catalyst described in the above technical solution, comprising the following steps:

[0013] The carrier, the water-soluble nickel source, water and the organic acid are mixed and heat-treated to obtain a supported nickel precursor;

[0014] The loaded nickel precursor is calcined, and after the organic acid is volatilized, the nickel-based loaded catalyst is obtained; the calcination temperature is 300-600°C.

[0015] Preferably, the organic acid comprises one or more of citric acid, malic acid, lactic acid and acetic acid;

[0016] The molar ratio of the water-soluble nickel source to the organic acid is 1:2-3.

[0017] Preferably, the heat treatment is carried out at a temperature of 60 to 120° C. and for a time of 1 to 5 hours.

[0018] Preferably, the calcination time is 3 to 6 hours.

[0019] The present invention also provides the use of the nickel-based supported catalyst described in the above technical solution or the nickel-based supported catalyst prepared by the preparation method described in the above technical solution in catalyzing carbon dioxide methanation.

[0020] The present invention also provides a method for methanation of carbon dioxide, comprising the following steps:

[0021] Mixing a reaction gas and a catalyst, and performing a methanogenic reaction using low-temperature plasma to obtain methane; the reaction gas includes CO2 and H2;

[0022] The catalyst is the nickel-based supported catalyst described in the above technical solution or the nickel-based supported catalyst prepared by the preparation method described in the above technical solution;

[0023] The discharge power for generating the low-temperature plasma is ≥25W.

[0024] The present invention provides a nickel-based supported catalyst, comprising a carrier and nickel oxide supported on the surface and in the pores of the carrier; the carrier comprises carbonate and / or citrate. The present invention uses carbonate and / or citrate as a carrier, which has higher catalytic activity; and the nickel-based supported catalyst of the present invention has a larger specific surface area, a smaller particle size, and a stronger mutual binding effect between the nickel oxide and the carrier, has excellent stability, and can achieve long-term catalytic CO2 methanation under low temperature conditions. In addition, the carrier used in the present invention has a large reserve amount and a wide source, and has the advantages of low cost, non-toxicity and mechanical stability.

[0025] The present invention also provides a method for preparing the nickel-based supported catalyst described in the above technical solution. The present invention uses organic acid as fuel and synthesizes the nickel-based supported catalyst by solution combustion method. Compared with the conventional sol-gel method, coprecipitation method and impregnation method, the present invention has a larger specific surface area and a smaller particle size, and the preparation method of the present invention is simple and suitable for large-scale industrial production. Furthermore, the loading amount of nickel oxide in the present invention is 2 to 15wt%, which has the advantage of lower cost.

[0026] The present invention also provides a method for methanation of carbon dioxide. The present invention combines a nickel-based supported catalyst with a low-temperature plasma. After the catalyst is discharged by the low-temperature plasma, the nickel oxide and the nickel oxide oxidized by air are also reduced to nickel element, thereby enhancing its ability to adsorb CO2 and H2. At the same time, the structure and morphology of the catalyst itself will not change greatly under the low-temperature plasma conditions, and a large specific surface area can be maintained, thereby realizing catalytic methanation of CO2 at room temperature and pressure, having excellent low-temperature catalytic activity, and having a high CO2 conversion rate and CH4 selectivity. It can be seen from the results of the embodiments of the present invention that the CO2 conversion rate can reach up to 93.8%, and the CH4 selectivity can reach up to 98.1%. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0028] Figure 1 The CO2 conversion curves when the catalysts obtained in Examples 1 to 5 and Comparative Examples 1 to 5 are used in CO2 methanation reactions;

[0029] Figure 2 The CH4 selectivity curves when the catalysts obtained in Examples 1 to 5 and Comparative Examples 1 to 5 are used in CO2 methanation reactions;

[0030] Figure 3 This is a graph showing the catalyst stability test results obtained in Example 1;

[0031] Figure 4 is a SEM image of the catalyst obtained in Example 1;

[0032] Figure 5 This is the particle size distribution diagram of the catalyst obtained in Example 1. DETAILED DESCRIPTION

[0033] The present invention provides a nickel-based supported catalyst, comprising a support and nickel oxide supported on the surface and in the pores of the support;

[0034] The carrier includes carbonate and / or citrate.

[0035] In the present invention, the carbonate includes one or more of calcium carbonate, potassium carbonate and magnesium carbonate, and in a specific embodiment, it can be calcium carbonate; the citrate includes one of sodium citrate, calcium citrate and potassium citrate. The present invention uses carbonate and / or citrate as a carrier, which has higher catalytic activity; and the nickel-based supported catalyst of the present invention has a larger specific surface area, a smaller particle size, and a stronger mutual binding effect between nickel oxide and the carrier, has excellent stability, and can achieve long-term catalytic CO2 methanation under low temperature conditions. In addition, the calcium carbonate reserve is large, and has the advantages of low cost, non-toxicity and mechanical stability.

[0036] In the present invention, the loading amount of the nickel oxide is 2-15 wt %, and in a specific embodiment, it can be 3 wt %, 5 wt %, 8 wt %, 10 wt % or 12 wt %.

[0037] In the present invention, the specific surface area of ​​the nickel-based supported catalyst is 20 to 30 m 2 / g, in a specific embodiment, it can be 23.86m 2 / g or 25.00m 2 / g; the pore size of the nickel-based supported catalyst is 5 to 15 nm, and in a specific embodiment, it can be 7, 9.63 or 12.10 nm; the pore volume is 0.02 to 0.05 cm 3 / g, in a specific embodiment, it can be 0.025, 0.037 or 0.042 cm 3 / g.

[0038] The present invention also provides a method for preparing the nickel-based supported catalyst described in the above technical solution, comprising the following steps:

[0039] The carrier, the water-soluble nickel source, water and the organic acid are mixed and heat-treated to obtain a supported nickel precursor;

[0040] The loaded nickel precursor is calcined, and the organic acid is volatilized and then reduced to obtain the nickel-based loaded catalyst; the calcination temperature is 300-600°C.

[0041] In the present invention, unless otherwise specified, all preparation raw materials are commercially available products well known to those skilled in the art.

[0042] The present invention mixes a carrier, a water-soluble nickel source, water and an organic acid, and performs heat treatment to obtain a loaded nickel precursor. In the present invention, the water-soluble nickel source includes a water-soluble nickel salt, which is one or more of nickel sulfate, nickel chloride and nickel nitrate, and in a specific embodiment, it can be nickel nitrate, more specifically Ni(NO3)2·6H2O; the organic acid includes one or more of citric acid, malic acid, lactic acid and acetic acid, and in a specific embodiment, it can be citric acid; the molar ratio of the water-soluble nickel source to the organic acid is 1:2-3, and in a specific embodiment, it can be 1:2.2 or 1:2.5.

[0043] In the present invention, a carrier, a water-soluble nickel source and water are first mixed to obtain a mixed solution; the mixed solution is mixed with an organic acid and heat-treated to obtain a loaded nickel precursor; the heat treatment temperature is 60 to 120°C, and in a specific embodiment, it can be 80°C or 100°C, and the time is 1 to 5 hours, and in a specific embodiment, it can be 2 or 4 hours; the mixing and heat treatment are carried out under stirring conditions, and the present invention has no special limitation on the stirring rate. The present invention loads nickel in ionic form on the carrier through heat treatment, and the low-temperature heat treatment evaporates the solution to form a dry solid without prematurely oxidizing the nickel ions.

[0044] A loaded nickel precursor is obtained, and the present invention calcines the loaded nickel precursor, and reduces it after the organic acid is volatilized to obtain the nickel-based loaded catalyst. In the present invention, the calcination temperature is 300-600°C, and in a specific embodiment, it can be 350°C, 400°C or 480°C, and the time is 3-6h, and in a specific embodiment, it can be 3.5h, 4h or 5h. The present invention volatilizes and decomposes the organic acid on the surface and in the pores of the loaded nickel precursor through calcination, so that the carrier forms a porous structure, and the nickel ions are evenly dispersed, so as to obtain a porous nickel ion-loaded catalyst precursor with a large specific area.

[0045] The present invention also provides the use of the nickel-based supported catalyst described in the above technical solution or the nickel-based supported catalyst prepared by the preparation method described in the above technical solution in catalyzing carbon dioxide methanation.

[0046] The present invention also provides a method for methanation of carbon dioxide, comprising the following steps:

[0047] Mixing a reaction gas and a catalyst, and performing a methanogenic reaction using low-temperature plasma to obtain methane; the reaction gas includes CO2 and H2;

[0048] The catalyst is the nickel-based supported catalyst described in the above technical solution or the nickel-based supported catalyst prepared by the preparation method described in the above technical solution;

[0049] The discharge power for generating the low-temperature plasma is ≥25W.

[0050] In the present invention, the molar ratio of CO2 to H2 is 1:1-8, and in a specific embodiment, it can be 1:3 or 1:5; the total flow rate of the reaction gas is 200-500 sccm, and in a specific embodiment, it can be 300 or 400 sccm; the space velocity is 15000-37500 h -1 In a specific embodiment, it can be 22500h -1 or 30000h -1 ; The discharge power for generating the low-temperature plasma is ≥25W), which can be 25 to 60W. In a specific embodiment, it can be 31W, 43W or 55W; the pressure is normal pressure.

[0051] The present invention combines a nickel-based supported catalyst with low-temperature plasma. After the catalyst is discharged by the low-temperature plasma, the nickel oxide oxidized by air will also be reduced to nickel element, thereby enhancing its ability to adsorb CO2 and H2. At the same time, under the condition of low-temperature plasma, the structure and morphology of the catalyst itself will not change greatly, and a large specific surface area can be maintained, thereby realizing catalytic CO2 methanation at room temperature and pressure, having excellent low-temperature catalytic activity, and having a high CO2 conversion rate and CH4 selectivity.

[0052] In order to further illustrate the present invention, the nickel-based supported catalyst provided by the present invention, its preparation method and application, and the method for methanation of carbon dioxide are described in detail below in conjunction with the accompanying drawings and examples, but they should not be construed as limiting the scope of protection of the present invention.

[0053] Example 1

[0054] Mix 3.75 g Ni(NO3)2·6H2O and 5 g CaCO3 with 10 mL deionized water and stir to obtain a mixed solution;

[0055] The mixed solution was stirred continuously at 80° C. for 2 h, and then 4.53 g of citric acid was added to obtain a suspension, and the mixture was stirred at 80° C. until a solid-state supported nickel precursor was obtained;

[0056] The obtained solid-state supported nickel precursor was placed in a muffle furnace and calcined at 300° C. for 4 h in an air atmosphere to obtain a nickel-based supported calcium carbonate catalyst.

[0057] Example 2

[0058] Mix 2.5 g Ni(NO3)2·6H2O and 5 g CaCO3 with 9 mL deionized water and stir to obtain a mixed solution;

[0059] The mixed solution was stirred continuously at 80° C. for 2 h, and then 3.02 g of citric acid was added to obtain a suspension, which was continued to be stirred at 80° C. until a solid-state supported nickel precursor was obtained;

[0060] The obtained solid-state supported nickel precursor was placed in a muffle furnace and calcined at 300° C. for 4 h in an air atmosphere to obtain a nickel-based supported calcium carbonate catalyst.

[0061] Example 3

[0062] Mix 1.25 g Ni(NO3)2·6H2O and 5 g CaCO3 with 8 mL deionized water and stir to obtain a mixed solution;

[0063] The mixed solution was stirred continuously at 80° C. for 2 h, and then 1.51 g of citric acid was added to obtain a suspension, which was continued to be stirred at 80° C. until a solid-state supported nickel precursor was obtained;

[0064] The obtained solid-state supported nickel precursor was placed in a muffle furnace and calcined at 300° C. for 4 h in an air atmosphere to obtain a nickel-based supported calcium carbonate catalyst.

[0065] Example 4

[0066] Mix 0.75 g Ni(NO3)2·6H2O and 5 g CaCO3 with 7 mL deionized water and stir to obtain a mixed solution;

[0067] The mixed solution was stirred continuously at 80° C. for 2 h, and then 0.91 g of citric acid was added to obtain a suspension, which was continued to be stirred at 80° C. until a solid-state supported nickel precursor was obtained;

[0068] The obtained solid-state supported nickel precursor was placed in a muffle furnace and calcined at 300° C. for 4 h in an air atmosphere to obtain a nickel-based supported calcium carbonate catalyst.

[0069] Example 5

[0070] Mix 0.5 g Ni(NO3)2·6H2O and 5 g CaCO3 with 6 mL deionized water and stir to obtain a mixed solution;

[0071] The mixed solution was stirred continuously at 80° C. for 2 h, and then 0.61 g of citric acid was added to obtain a suspension, which was continued to be stirred at 80° C. until a solid-state supported nickel precursor was obtained;

[0072] The obtained solid-state supported nickel precursor was placed in a muffle furnace and calcined at 300° C. for 4 h in an air atmosphere to obtain a nickel-based supported calcium carbonate catalyst.

[0073] Comparative Example 1

[0074] Mix 3.75 g Ni(NO3)2·6H2O and 5 g CaCO3 with 10 mL deionized water and stir to obtain a mixed solution;

[0075] The mixed solution was stirred continuously at 80° C. for 2 h, and then 3.88 g of urea was added to obtain a suspension, which was continued to be stirred at 80° C. until a solid-state supported nickel precursor was obtained;

[0076] The obtained solid-state supported nickel precursor was placed in a muffle furnace and calcined at 300° C. for 4 h in an air atmosphere to obtain a nickel-based supported calcium carbonate catalyst.

[0077] Comparative Example 2

[0078] Mix 0.75 g Ni(NO3)2·6H2O and 5 g CaCO3 with 10 mL deionized water and stir to obtain a mixed solution;

[0079] The mixed solution was stirred continuously at 80° C. for 2 h, and then 2.75 g of sucrose was added to obtain a suspension, and the mixture was stirred at 80° C. until a solid-state supported nickel precursor was obtained;

[0080] The obtained solid-state supported nickel precursor was placed in a muffle furnace and calcined at 300° C. for 4 h in an air atmosphere to obtain a nickel-based supported calcium carbonate catalyst.

[0081] Comparative Example 3

[0082] Mix 0.75 g Ni(NO3)2·6H2O and 5 g CaCO3 with 10 mL deionized water and stir to obtain a mixed solution;

[0083] The mixed solution was stirred continuously at 80° C. for 4 h until a solid-state supported nickel precursor was obtained;

[0084] The obtained solid-state supported nickel precursor was placed in a muffle furnace and calcined at 300° C. for 4 h in an air atmosphere to obtain a nickel-based supported calcium carbonate catalyst.

[0085] Comparative Example 4

[0086] Mix 0.75 g Ni(NO3)2·6H2O and 5 g SiO2 with 10 mL deionized water and stir to obtain a mixed solution;

[0087] The mixed solution was stirred continuously at 80° C. for 2 h, and then 4.53 g of citric acid was added to obtain a suspension, and the mixture was stirred at 80° C. until a solid-state supported nickel precursor was obtained;

[0088] The obtained solid-state supported nickel precursor was placed in a muffle furnace and calcined at 300° C. for 4 h in an air atmosphere to obtain a nickel-based supported SiO 2 catalyst.

[0089] Comparative Example 5

[0090] Mix 0.75 g Ni(NO3)2·6H2O and 5 g Al2O3 with 10 mL deionized water and stir to obtain a mixed solution;

[0091] The mixed solution was stirred continuously at 80° C. for 2 h, and then 4.53 g of citric acid was added to obtain a suspension, and the mixture was stirred at 80° C. until a solid-state supported nickel precursor was obtained;

[0092] The obtained solid-state supported nickel precursor was placed in a muffle furnace and calcined at 300° C. for 4 h in an air atmosphere to obtain a nickel-based supported Al 2 O 3 catalyst.

[0093] Comparative Example 6

[0094] 3.75 g Ni(NO3)2·6H2O and 5 g CaCO3 were mixed with 10 mL deionized water and stirred continuously at 80 °C for 2 h. The obtained solid was placed in a muffle furnace and calcined at 300 °C for 4 h to obtain a nickel-based supported calcium carbonate catalyst with a specific surface area of ​​0.51 m 2 / g, which is a non-porous structure.

[0095] Test Case

[0096] The catalytic performance of the catalysts obtained in Examples 1 to 5 and Comparative Examples 1 to 5 for the methanation of carbon dioxide was evaluated in an atmospheric pressure dielectric barrier discharge fixed bed reactor, and the specific steps were as follows:

[0097] Before the reaction, 100 mg of the catalysts obtained in Examples 1 to 5 and Comparative Examples 1 to 5 were added to the reactor. Under the control of a mass flow controller, a mixture of H2 and CO2 was introduced into the reactor at a total flow rate of 300 sccm, and the corresponding space velocity was 22500 h -1, the gas component molar ratio is H2:CO2=5, and then the catalysts obtained in Examples 1 to 5 and Comparative Examples 1 to 5 are tested for CO2 methanation activity using low-temperature plasma with different discharge powers. The products of CO2 methanation, CH4 and CO, and unreacted CO2 are analyzed by an online gas chromatograph (GC, Agilent 8860), which is equipped with a capillary column (HP-PLOT / Q) and a molecular sieve column (G3591-80022, TDX-01), and is equipped with a thermal conductivity detector (TCD) and a flame ionization detector (FID). The CO2 conversion rate and CH4 selectivity are calculated using the data output by the gas chromatograph, and the results are shown below.

[0098] Table 1 CO2 conversion results of catalysts obtained in Examples 1 to 5 and Comparative Examples 1 to 5 at different powers

[0099]

[0100] Table 2 CH4 selectivity results of catalysts obtained in Examples 1 to 5 and Comparative Examples 1 to 5 at different powers

[0101]

[0102] Figure 1 The CO2 conversion curves when the catalysts obtained in Examples 1 to 5 and Comparative Examples 1 to 5 are used in CO2 methanation reactions. Figure 2 The CH4 selectivity curves of the catalysts obtained in Examples 1 to 5 and Comparative Examples 1 to 5 when used in CO2 methanation reaction; from Tables 1 to 2 and Figures 1-2 The results show that the catalytic performance of the catalysts prepared in the examples of the present invention is significantly better than that of the catalysts prepared in the comparative examples, and the catalyst prepared in Example 1 has the highest low-temperature catalytic activity.

[0103] Figure 3 is a graph showing the stability test results of the catalyst obtained in Example 1. Figure 3 The results show that the nickel-based supported calcium carbonate catalyst provided by the present invention has excellent stability.

[0104] Figure 4 is the SEM image of the catalyst obtained in Example 1, Figure 5 is the particle size distribution diagram of the catalyst obtained in Example 1, Figures 4-5 It can be seen that the specific surface area of ​​the catalyst prepared by the present invention is 23.86m 2 / g, pore diameter is 9.63nm, pore volume is 0.037cm 3 / g, with larger specific surface area and smaller particle size.

[0105] In addition, it can be seen from Example 1 and Comparative Example 6 that the catalyst prepared by the solution combustion method of the present invention can transform a non-porous structure into a porous structure compared to the traditional impregnation method, has a larger specific surface area, and improves its ability to adsorb carbon dioxide and hydrogen, thereby improving the CO2 conversion rate and CH4 selectivity.

[0106] Although the above embodiment describes the present invention in detail, it is only a part of the embodiments of the present invention, not all of the embodiments. People can also obtain other embodiments based on this embodiment without creativity, and these embodiments all fall within the protection scope of the present invention.

Claims

1. A nickel-based supported catalyst, characterized in that It includes a carrier and nickel oxide loaded on the surface and pores of the carrier; The carrier includes carbonate and / or citrate.

2. The nickel-based supported catalyst according to claim 1, characterized in that The carbonate includes one or more of calcium carbonate, potassium carbonate and magnesium carbonate; The citrate includes one or more of sodium citrate, calcium citrate and potassium citrate.

3. The nickel-based supported catalyst according to claim 1 or 2, characterized in that The loading amount of the nickel oxide is 2-15 wt %.

4. The method for preparing the nickel-based supported catalyst according to any one of claims 1 to 3, characterized in that: The following steps are involved: The carrier, the water-soluble nickel source, water and the organic acid are mixed and heat-treated to obtain a supported nickel precursor; The loaded nickel precursor is calcined, and after the organic acid is volatilized, the nickel-based loaded catalyst is obtained; the calcination temperature is 300-600°C.

5. The preparation method according to claim 4, characterized in that: The organic acid includes one or more of citric acid, malic acid, lactic acid and acetic acid; The molar ratio of the water-soluble nickel source to the organic acid is 1:2-3.

6. The preparation method according to claim 4, characterized in that: The heat treatment temperature is 60-120° C. and the time is 1-5 hours.

7. The preparation method according to claim 4, characterized in that: The calcination time is 3 to 6 hours.

8. Use of the nickel-based supported catalyst according to any one of claims 1 to 3 or the nickel-based supported catalyst prepared by the preparation method according to any one of claims 4 to 7 in catalytic carbon dioxide methanation.

9. A method for methanation of carbon dioxide, characterized in that: The following steps are involved: Mixing a reaction gas and a catalyst, and performing a methanogenic reaction using low-temperature plasma to obtain methane; the reaction gas includes CO2 and H2; The catalyst is the nickel-based supported catalyst according to any one of claims 1 to 3 or the nickel-based supported catalyst prepared by the preparation method according to any one of claims 4 to 7; The discharge power for generating the low-temperature plasma is ≥25W.

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