Co-CeO2 doped oxide catalyst, Au / Co-CeO2 doped oxide catalyst as well as preparation method and application of Co-CeO2 doped oxide catalyst and Au / Co-CeO2 doped oxide catalyst

Abstract

The invention relates to the technical field of VOCs removal through plasma catalytic oxidation, in particular to a Co-CeO2 doped oxide catalyst, an Au / Co-CeO2 doped oxide catalyst and a preparation method and application of the Co-CeO2 doped oxide catalyst and the Au / Co-CeO2 doped oxide catalyst. The Co-CeO2 doped oxide catalyst is prepared through pyrolysis of aerosol of a cerium-containing compound and a cobalt-containing compound, has relatively low cost and relatively high catalytic activity, is combined with plasma discharge, is used for removing alkane VOCs in printing and waste gas treatment industries, can reduce the temperature of complete catalytic oxidation, and has a good application prospect. The generation of byproducts is reduced. The Co-CeO2 doped oxide catalyst is loaded with a small amount of precious metal Au to prepare the Au / Co-CeO2 catalyst, and the catalytic oxidation performance of the Au / Co-CeO2 catalyst on alkane VOCs can be further improved. The catalyst is low in raw material cost, simple in preparation process and wide in market prospect.

Description

Technical Field

[0001] The present invention belongs to the technical field of plasma catalytic oxidation removal of VOCs, and specifically relates to a Co-CeO2 doped oxide catalyst, an Au / Co-CeO2 doped oxide catalyst, and a preparation method and application thereof. Background Art

[0002] With the rapid development of economy and industry, the emission of volatile organic compounds (VOCs) generated in the industrial production process has also increased. VOCs are carcinogenic, teratogenic and mutagenic. Long-term exposure to the atmosphere containing various VOCs has seriously harmed people's health. In addition, the photochemical reaction of VOC-NOx increases the ozone concentration in the atmospheric troposphere, enhancing the greenhouse effect. Under the action of sunlight and heat, it participates in the nitrogen oxide reaction to form ozone, resulting in poor air quality and is the main component of summer photochemical smog and urban haze. Among alkane VOCs, the catalytic degradation of long-chain alkanes has always been a difficult problem to overcome. As a typical long-chain alkane and the main component of volatile organic compounds (VOCs) emitted by the printing industry, n-undecane (C11) should be controlled when it is emitted into the atmosphere.

[0003] The main control technologies for alkane VOCs emissions include adsorption, catalytic combustion, catalytic oxidation, biodegradation, photocatalysis and plasma. Among them, the catalytic oxidation method is to promote the reaction of VOCs with oxygen at a lower temperature through the action of a catalyst, and convert them into harmless carbon dioxide and water, thereby achieving purification. This technology has the advantages of low energy consumption, no secondary pollution, good safety and a wide range of applications.

[0004] The document with patent number CN117643879A provides "a catalyst for catalytic oxidation of VOCs, its preparation method and application". The catalyst carrier is calcined once to obtain a calcined product, and then the calcined product, a platinum source and nitric acid are mixed and calcined twice to obtain a catalyst with excellent catalytic efficiency, which can efficiently oxidize volatile organic compounds.

[0005] The document with patent number CN116764617A provides "a catalyst for catalytic oxidation of volatile organic compounds, its preparation method and application". The catalyst contains an alkaline earth metal modified alumina carrier and an alkali metal (the alkaline earth metal is one or more of magnesium, calcium, strontium and barium) and a precious metal (the precious metal is selected from one or more of Pt, Pd, Rh, Ru, Ag and Au) loaded on the modified alumina carrier. The prepared catalyst has a micro-mesoporous multi-level pore structure and has higher catalytic activity and stability for VOCs.

[0006] The document with patent number CN105013477A provides "a mixed-phase titanium dioxide-loaded ruthenium catalyst for catalytic oxidation of VOCs, a preparation method and its use". The catalyst uses rutile phase titanium dioxide modified with anatase phase titanium dioxide as a carrier, and the active component is ruthenium or ruthenium oxide. The complete oxidation temperature for a variety of VOCs is between 155 and 240°C. The overall performance is better than commercial platinum and palladium catalysts, and the selectivity of the reaction final product carbon dioxide is close to 100%.

[0007] The document with patent number CN115722220B provides "a catalytic oxidation catalyst, its preparation method and application". The catalyst uses the precious metal RuO2 as the active component, the composite metal oxide SnO2 / MgO / CuO-TiO2 as the modified carrier, and the porous ceramic is cordierite. The catalyst has high catalytic activity and excellent catalytic stability when used in catalytic combustion CVOCs.

[0008] The document with patent number CN116273024A provides "a highly efficient monolithic catalyst for catalytic oxidation of OVOCs and its preparation method and application". The monolithic catalyst uses an in-situ hydrothermal growth method to attach transition metal cobalt and nickel to a foam nickel carrier. The T of butyl acetate oxygenated VOCs (OVOCs) of the 0.75Co / Ce monolithic catalyst is 90 The temperature is around 210℃.

[0009] The document with patent number CN110124663A provides "a catalyst for catalytic oxidation of VOCs, its preparation method and application". The provided MaOb / MnO2 composite non-precious metal oxide catalyst, the metal element M is one or more selected from Co, Cu, Fe, Ni, Mg, Al, Zn, Ce and Sb; a is the atomic ratio of the metal element M, which is 0 to 5; b is the oxygen atomic ratio in the corresponding metal oxide. The catalyst can completely oxidize VOCs into CO2 and H2O at a temperature of 100 to 400°C in a fixed bed. When the reaction temperature is 215 to 220°C, the conversion rate of the reaction can reach more than 90%.

[0010] However, in the existing technology, it is still difficult to completely oxidize low-temperature VOCs (≤100°C), and the catalyst preparation process is complicated and the cost is high. The technology combining low-temperature plasma and catalysis has high VOCs degradation efficiency, product selectivity and energy efficiency, and is considered to be one of the most promising technologies for degrading VOCs.

[0011] The document with patent number CN108465354A provides "Low-temperature plasma synergistic catalytic reaction unit and VOCs treatment device and method based on the reaction unit". The invention provides a VOCs treatment device based on a low-temperature plasma synergistic catalytic reactor. VOCs waste gas enters the device, and is processed by a particulate matter filtration unit, a low-temperature plasma synergistic catalytic reaction unit and an ozone decomposition catalytic reaction unit in sequence, and the purified gas is discharged from the device.

[0012] The document with patent number CN202310892923.1 provides "a method for synergistic resource treatment of CO2 and VOCs at normal temperature and pressure". CO2 and VOCs are used as reaction gases, and the reaction is carried out in a DBD plasma reactor loaded with a Ni-based catalyst to prepare synthesis gas; the VOCs are benzene, toluene or xylene; the Ni-based catalyst is at least one of Ni / BaTiO3, Ni / CeO2, Ni / ZrO2 and Ni / MnO2.

[0013] Patent No. CN202111565348.1 discloses a plasma catalyst and its preparation method and application. The catalyst contains a carrier and an active component element and an auxiliary element loaded on the carrier, the carrier is selected from at least one of Al2O3, SiO2, MgO, ZrO2, and molecular sieves, the active component element is selected from at least one of Pt, Rh, Pd, and Ir, and the auxiliary element is selected from at least one of Group VIII non-precious metal elements and Group IB metal elements. The catalyst provided by the present invention can adapt to the composition changes of the tail gas after the natural gas undergoes a plasma reaction, realize the one-step conversion of natural gas into acrylic acid at low temperature and normal pressure, and can effectively and stably improve the selectivity of acrylic acid.

[0014] Patent number CN116809053A discloses a cerium-based catalyst with plasma-enhanced chlorine resistance, wherein the cerium-based catalyst is specifically a V / CeO2 composite material; the V / CeO2 composite material is obtained by loading V on a CeO2 carrier by an impregnation method; the mass fraction of V in the V / CeO2 catalyst is 0.1wt%-0.6wt%.

[0015] CN202210225192.0 discloses a method for preparing a single-atom catalyst and a VOCs treatment process. The preparation method is as follows: 1) The CeO2 carrier is pretreated by plasma chemical vapor deposition to obtain a CeO2 carrier densely covered with defects. 2) The CeO2 carrier treated in step one is added to a silver ammonia solution and stirred so that Ag is anchored to the defects on the surface of the CeO2 carrier. 3) The product obtained in step two is calcined to obtain an Ag / CeO2 single-atom catalyst. The invention uses a method for preparing a single-atom catalyst after pretreating the carrier by plasma chemical vapor deposition. Argon gas is introduced to etch the CeO2 carrier, and the plasma modifies the defect sites and electronic structure of the CeO2 carrier, which is more conducive to effectively improving the loading rate of the noble metal single atoms in the single-atom catalyst, improving the utilization rate of the noble metal atoms and the catalytic effect and stability of the single-atom catalyst. Summary of the invention

[0016] The present invention provides a Co-CeO2 doped oxide catalyst and an Au / Co-CeO2 doped oxide catalyst which can achieve complete conversion of alkane VOCs (taking n-undecane (C11) as an example, but not limited to n-undecane) under the conditions that the catalytic oxidation reaction temperature is less than 100°C and the plasma energy density (the discharge energy received by a unit volume of gas) is less than 50 J / L.

[0017] The catalyst is a Co-CeO2 doped oxide catalyst, which is prepared by a high temperature decomposition method of aerosol containing cobalt compounds and cerium compounds, and the specific steps are as follows:

[0018] S11: Atomizing the aqueous solution of the cobalt-containing compound and the cerium-containing compound, the mist is brought into the insulation tube (temperature is 60-70° C.) via the inert gas, and the water is vaporized to generate an aerosol containing small solid particles of the cobalt-containing compound and the cerium-containing compound;

[0019] S12: the aerosol is introduced into a high temperature decomposition tube (temperature is 400-700° C.) along with the inert gas to decompose into cobalt tetroxide and cerium dioxide to form a partially or fully doped Co-CeO2 doped oxide solid product;

[0020] S13: The Co-CeO2 doped oxide solid product enters the water absorption bottle along with the inert gas, and after the water is collected, it is separated by high-speed centrifugation, and the Co-CeO2 doped oxide catalyst is obtained after drying (temperature is 80°C, drying time is 0.1-12 hours).

[0021] Furthermore, the cobalt compound is cobalt nitrate; and the cerium-containing compound is cerium nitrate.

[0022] Furthermore, the inert gas includes nitrogen.

[0023] Furthermore, the atomic ratio of cobalt Co to cerium Ce in the Co-CeO2 doped oxide catalyst is 0.17-6.

[0024] Preferably, the atomic ratio of cobalt Co to cerium Ce in the Co-CeO2 doped oxide catalyst is 4.

[0025] Furthermore, the Co-CeO2 doped oxide catalyst is a hollow sphere composed of solid spheres ranging from a few nanometers to tens of nanometers. The hollow sphere can be open or closed, and the outer diameter of the hollow sphere is between 100 nanometers and 10 micrometers.

[0026] The Au / Co-CeO2 doped oxide catalyst is prepared by the Co-CeO2 doped oxide prepared by the above method, and is obtained by loading gold (Au) on the surface of the Co-CeO2 doped oxide catalyst by an impregnation method. The preparation method comprises the following steps:

[0027] S21: Disperse the Co-CeO2 doped oxide catalyst evenly in the chloroauric acid solution, stir evenly at room temperature, and place in a dark place for 12 hours for aging;

[0028] S22: The aged catalyst solution was dried in an oven at 80°C for 6 hours, placed in a muffle furnace, calcined at 500-600°C for 2-4 hours in an air atmosphere, and then naturally cooled to room temperature to obtain an Au / Co-CeO2 doped oxide catalyst.

[0029] Furthermore, the loading mass of Au in the Au / Co-CeO2 doped oxide catalyst is 0.01%-1% of the Co-CeO2 doped oxide catalyst.

[0030] Preferably, the loading mass of Au in the Au / Co-CeO2 doped oxide catalyst is 0.01% to 0.1% of the Co-CeO2 doped oxide catalyst.

[0031] Furthermore, the concentration of the chloroauric acid solution is 0.099 g / ml.

[0032] The above-mentioned Co-CeO2 doped oxide catalyst or Au / Co-CeO2 doped oxide catalyst is applied to the plasma catalytic oxidation purification of alkane organic volatile substances (VOCs) in the air.

[0033] Furthermore, the plasma catalytic oxidation conditions are: plasma intensity is 25-45 J / L, and catalytic oxidation temperature is 50-100°C.

[0034] The alkane-based organic volatile substances (VOCs) are preferably n-undecane.

[0035] Preferably, when the Co-CeO2 doped oxide catalyst is used for plasma catalytic oxidation purification of alkane organic volatile substances (VOCs) in the air, the plasma catalytic oxidation conditions are: plasma intensity of 0 to 50 J / L, and catalytic oxidation temperature of room temperature to 100°C.

[0036] Preferably, when the Au / Co-CeO2 doped oxide catalyst is used for plasma catalytic oxidation purification of alkane organic volatile substances (VOCs) in the air, the plasma catalytic oxidation conditions are: plasma intensity is 25 to 40 J / L, and catalytic oxidation temperature is 50 to 70°C.

[0037] Compared with the prior art, the present invention has the following beneficial effects:

[0038] (1) An object of the present invention is to provide a Co-CeO2 doped oxide catalyst as described above, and its use in the catalytic oxidation of alkane VOCs, such as C11.

[0039] (2) The Co-CeO2 catalyst of the present invention has high activity for the catalytic oxidation of the volatile organic pollutant C11 and can achieve 100% conversion of C11 at a relatively low temperature and energy density.

[0040] (3) The present invention uses base metal doping, high temperature, nano-engineering, and interface to achieve low-temperature gasification of carbonate on the catalyst surface, release active sites, and achieve efficient degradation of C11. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] Figure 1 Schematic diagram of the preparation method of Co-CeO2 doped oxide catalyst;

[0042] Figure 2 A device for preparing Co-CeO2 doped oxide catalyst;

[0043] Figure 3 This is an electron microscope image of the Co-CeO2 doped oxide catalyst when the atomic ratio of cobalt Co to cerium Ce is 4;

[0044] Figure 4 This is a transmission electron microscope image of the Co-CeO2 doped oxide catalyst when the atomic ratio of cobalt Co to cerium Ce is 4;

[0045] Figure 5 The XRD spectrum of CeO2-doped oxide catalyst when the atomic ratio of cobalt Co to cerium Ce is 4;

[0046] Figure 6The graph shows the relationship between the C11 conversion (1), CO2 selectivity (2) and plasma energy density of CeO2-doped oxide catalysts with different cobalt Co and cerium Ce atomic ratios, CeO2, and Co3O4 at the same temperature;

[0047] Figure 7 The graph is a relationship between the C11 conversion rate and the reaction temperature of the CeO2-doped oxide catalyst with a Co to Ce atomic ratio of 4 at the same plasma energy density;

[0048] Figure 8 Schematic diagram of the preparation method of Au / Co-CeO2 oxide catalyst;

[0049] Fig. 9 This is an electron microscope image of the Au / Co-CeO2 catalyst with an Au loading of 0.1%;

[0050] Fig.10 Transmission electron microscopy image of Au / Co-CeO2 catalyst with Au loading of 0.1%;

[0051] Fig.11 The XRD pattern of Au / Co-CeO2 catalyst with Au loading of 0.1%;

[0052] Fig.12 The relationship between C11 conversion (1), CO2 selectivity (2) and energy density of Au / Co-CeO2 oxide catalysts with different Au loadings at the same temperature;

[0053] Fig.13 This is a graph showing the relationship between the C11 conversion rate and reaction temperature of Au / Co-CeO2 oxide catalysts with different Au loadings at the same plasma energy density. DETAILED DESCRIPTION

[0054] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and understandable, the specific implementation modes of the present invention are described in detail below with reference to the accompanying drawings, but they should not be construed as limiting the applicable scope of the present invention.

[0055] Example 1

[0056] A Co-CeO2 doped oxide catalyst comprising Figure 2 The device shown in the figure is prepared, including an ultrasonic atomization component, a carrier gas component, a heating component, a water absorption bottle and a conveying component. The ultrasonic atomization component includes a glass bottle and an ultrasonic atomizer arranged in the glass bottle. The carrier gas component includes a rotor flowmeter. The heating component includes a tubular electric furnace and an electric furnace temperature controller. The conveying component includes an insulation tube, a quartz tube (high temperature decomposition tube), an insulation controller and a discharge pipe. The parameters of the above instruments are shown in Table 1.

[0057] Based on the above device, see Figure 1 , the preparation method of Co-CeO2 doped oxide catalyst, the specific steps are as follows:

[0058] S1: An aqueous solution (50 mL) of cobalt nitrate and cerium nitrate was atomized by an ultrasonic atomizer, and the mist was carried into an insulation tube (70°C) by nitrogen gas (flow rate: 0.8 L / min). The liquid in the mist was vaporized in the insulation tube to generate an aerosol containing small solid particles of cobalt nitrate and cerium nitrate.

[0059] S2: The aerosol is introduced into a quartz tube along with nitrogen gas and decomposed at high temperature (500°C) to form cobalt tetroxide and cerium dioxide, and further to form a partially or fully doped Co-CeO2 doped oxide solid product.

[0060] S3: The Co-CeO2 doped oxide solid product and nitrogen etc. enter the water absorption bottle. After the Co-CeO2 doped oxide solid product is absorbed by water, it is separated by high-speed centrifugation (100,000 rpm, 5 minutes) and dried in a drying oven (80°C for 12 hours) to obtain the Co-CeO2 doped oxide catalyst.

[0061] Nitrogen can be replaced by other inert gases.

[0062] The amounts of cobalt nitrate and cerium nitrate used in step S1 are shown in Table 2, and a series of Co-CeO2 doped oxide catalysts with different Co / (cobalt Co+cerium Ce) atomic ratios are prepared.

[0063] Table 1

[0064]

[0065]

[0066] Table 2

[0067]

[0068]

[0069] The morphology and composition of Co-CeO2 doped oxide catalysts with an atomic ratio of cobalt (Co) to cerium (Ce) of 4 were characterized.

[0070] 1. The image of Co-CeO2 doped oxide catalyst with a cobalt Co to cerium Ce atomic ratio of 4 was taken by scanning electron microscope. Figure 3 The catalyst is an open or closed hollow sphere with a particle size of 100 nanometers to 10 micrometers. The sphere wall is composed of solid spheres with a size of several nanometers to tens of nanometers.

[0071] 2. The image of Co-CeO2 doped oxide catalyst with a cobalt Co to cerium Ce atomic ratio of 4 was taken by transmission electron microscopy. Figure 4 .from Figure 4 The lattice fringes of the (311) crystal plane of Co3O4 and the lattice fringes of the (111) crystal plane of CeO2 can be clearly displayed.

[0072] 3. XRD analysis of Co-CeO2 doped oxide catalyst when the atomic ratio of cobalt Co to cerium Ce is 4 is shown in Figure 5 The catalyst with a cobalt Co:Ce atomic ratio of 4 showed a peak dominated by ceria, indicating that cobalt, which is smaller than cerium atoms, was doped into the ceria framework.

[0073] The above results indicate that the Co-CeO2 doped oxide catalyst with an atomic ratio of cobalt (Co) to cerium (Ce) of 4 is a mixture of Co3O4 and CeO2 doped with lattice defects.

[0074] Example 2

[0075] Based on the Co-CeO2 doped oxide catalyst with a cobalt Co and cerium Ce atomic ratio of 4 prepared in Example 1, different loading amounts of Au were impregnated to provide an Au / Co-CeO2 oxide catalyst by an impregnation method. The preparation method is as follows: Figure 8 , the specific steps are as follows:

[0076] S1: Disperse the Co-CeO2 doped oxide catalyst evenly in a certain amount of prepared chloroauric acid impregnation solution, stir evenly at room temperature, and place it in a dark place for 12 hours for aging;

[0077] S2: The aged catalyst impregnation liquid is dried in an oven at 80°C for 6 hours, placed in a muffle furnace, calcined at 500°C for 2 hours in an air atmosphere, and then naturally cooled to room temperature to obtain an Au / Co-CeO2 doped oxide catalyst. The present invention is a catalyst for low-concentration C11 oxidation.

[0078] The amounts of chloroauric acid solution and 4Co-CeO2-doped oxide catalyst used are shown in Table 3, and catalysts with different Au loading ratios were prepared.

[0079] Table 3

[0080]

[0081] The morphology and composition of 0.1Au / 4Co-CeO2 oxide catalyst with Au loading of 0.1 were characterized.

[0082] 1. The image of 0.1Au / 4Co-CeO2 oxide catalyst taken by scanning electron microscope is shown in Fig. 9It can be seen that the loading of Au does not have much effect on the morphology of Co-CeO2 oxide catalyst.

[0083] 2. The image of 0.1Au / 4Co-CeO2 oxide catalyst taken by transmission electron microscope is shown in Fig.10 .from Fig.10 The lattice fringes of the (220) crystal plane of Co3O4, the lattice fringes of the (111) crystal plane of CeO2, and the (111) crystal plane of Au can be clearly shown, indicating that Au is loaded on the surface of 4Co-CeO2.

[0084] 3. XRD analysis of 0.1Au / 4Co-CeO2 oxide catalyst Fig.11 After loading Au, the XRD spectrum still mainly shows the main peaks of Co3O4 and CeO2. In contrast, there is no obvious main peak of Au, which may be due to the low loading amount and high dispersion of Au.

[0085] Effect Example 1

[0086] The catalytic oxidation performance of C11 by a series of Co-CeO2 doped oxide catalysts with different doping ratios prepared in Example 1 was evaluated using a flow-through fixed bed reactor.

[0087] Reaction conditions: 10% O2, N2 balance gas, C11 concentration 265 mg / m 3 The amount of Co-CeO2 doped oxide catalyst was 0.7 g, the total flow rate was 160 mL / min, the space velocity per unit mass was 13700 mL / (gh), and the discharge voltage was adjusted under the discharge conditions of frequency of 100 Hz and pulse width of 40000 ns to control the energy density at 0-45 J / L.

[0088] The relationship between the C11 conversion rate and plasma energy density (ED, the discharge energy J applied per unit volume L of gas) of Co-CeO2 doped oxide catalysts, CeO2, and Co3O4 with different cobalt Co / (cobalt Co + cerium Ce) atomic ratios at a reaction temperature of 90°C is shown in Figure 6 , and the sample without adding catalyst (None) was used as a comparative example.

[0089] Results: When the reaction temperature is 90℃, the C11 conversion rate of 4Co-CeO2 catalyst increases from 47.7% to 100% with the increase of plasma energy density. In the absence of catalyst, the C11 conversion rate increases from 0 to 68.6% with the increase of energy density. Increasing ED can significantly improve C11 conversion rate and CO2 selectivity.

[0090] The relationship between the C11 conversion rate and the reaction temperature of the Co-CeO2 doped oxide catalyst with a cobalt Co / (cobalt Co + cerium Ce) atomic ratio of 4 at an energy density of 30 J / L is shown in Figure 7 .

[0091] Results: With the increase of reaction temperature, the conversion rate of C11 also increases. When the catalyst exists alone (no discharge, no plasma catalysis), with the increase of reaction temperature, the conversion rate of C11 increases from 7.1% to 77.4%. Under the conditions of 100℃ and ED of 30J / L, the conversion rate of C11 is as high as 100%. This shows that plasma plays a very important role in the degradation of C11.

[0092] Since the Co-CeO2 doped oxide catalyst provided by the present invention can catalyze the oxidation of C11 efficiently at a relatively low reaction temperature and plasma energy density under oxygen-containing conditions, the present invention provides an application of a Co-CeO2 doped oxide catalyst in the oxidation of C11, especially in the following three aspects:

[0093] (1) Low-cost degradation of long-chain alkanes. Currently, there are a lot of studies on the catalytic oxidation of short-chain alkane VOCs, but the catalytic oxidation of long-chain alkanes is not in-depth, and most of them use catalysts such as precious metals. The transition metal catalyst provided by the present invention can effectively degrade C11 under low-cost conditions.

[0094] (2) Removal of VOCs in the printing industry. Since C11 is the main volatile organic compound produced in the printing industry, it seriously harms people's health and the atmospheric environment. The Co-CeO2 catalyst provided by the present invention can effectively remove C11 produced in the printing industry.

[0095] (3) Oxidation of C11 in the products of hydrocarbon fuel combustion (such as gasoline engines, diesel engines, etc.).

[0096] Effect Example 2

[0097] The catalytic oxidation performance of C11 over a series of Au / Co-CeO2 oxide catalysts with different loading ratios prepared in Example 2 was evaluated using a flow-through fixed bed reactor.

[0098] Reaction conditions: 10% O2, N2 balance gas, C11 concentration 265 mg / m 3 The amount of Au / 4Co-CeO2 oxide catalyst was 0.7 g, the total flow rate was 160 mL / min, the space velocity per unit mass was 13700 mL / (gh), and the discharge voltage was adjusted under the discharge conditions of frequency of 100 Hz and pulse width of 40000 ns to control the energy density at 0-40 J / L.

[0099] The relationship between the C11 conversion rate and energy density of Au / 4Co-CeO2 oxide catalysts with different Au loadings at a reaction temperature of 50°C is shown in Fig.12 .

[0100] At a reaction temperature of 50°C, the C11 conversion of the Au / 4Co-CeO2 catalyst increased from 28.5% to 100% with increasing energy density. In the absence of a catalyst, the C11 conversion increased from 0 to 58.5% with increasing energy density. Increasing ED can significantly improve C11 conversion and CO2 selectivity.

[0101] The relationship between the C11 conversion rate and the reaction temperature of the Au / Co-CeO2 doped oxide catalyst with an Au loading of 0.1 and a plasma energy density of 25 J / L is shown in Fig.13 .

[0102] As the reaction temperature increases, the C11 conversion rate also increases. When the catalyst exists alone (no discharge, no plasma catalysis), as the reaction temperature increases, the C11 conversion rate increases from 9.8% to 87.3%. Under the conditions of 70°C and ED of 25J / L, the C11 conversion rate is as high as 100%.

[0103] Based on the above ideal embodiments of the present invention, the relevant staff can make various changes and modifications without departing from the technical concept of the present invention through the above description. The technical scope of the present invention is not limited to the contents of the specification, and its technical scope must be determined according to the scope of the claims.

Claims

1. A Co-CeO 2 Method for preparing doped oxide catalyst, It is characterized in that The catalyst is prepared by a high temperature decomposition method of aerosol containing a cobalt compound and a cerium compound, comprising the following steps: S11: Atomizing the aqueous solution containing the cobalt compound and the cerium compound, the mist is brought into the insulation tube via the inert gas, and the water is vaporized to generate an aerosol containing small solid particles of the cobalt compound and the cerium compound; S12: The aerosol is introduced into a high-temperature decomposition tube along with the inert gas to decompose into cobalt tetroxide and cerium dioxide to form partially or fully doped Co-CeO 2 doping oxide solid products; S13: The Co-CeO 2 The doped oxide solid product enters the water absorption bottle along with the inert gas, and after the water is collected, it is separated by high-speed centrifugation, and the Co-CeO 2 Doped oxide catalysts.

2. The Co-CeO according to claim 1 2 Doped oxide catalysts, It is characterized in that The cobalt compound is cobalt nitrate; and the cerium-containing compound is cerium nitrate.

3. The Co-CeO according to claim 1 2 Doped oxide catalysts, It is characterized in that The Co-CeO 2 The atomic ratio of cobalt Co to cerium Ce in the doped oxide catalyst is 0.17-6.

4. The Co-CeO according to claim 1 2 Doped oxide catalysts, It is characterized in that The temperature of the insulation pipe is 60-70°C; The temperature of the high temperature decomposition tube is 400-700°C.

5. A Co-CeO prepared according to the method of claims 1-4 2 Doped oxide catalysts.

6. Au / Co-CeO 2 Doped oxide catalysts, It is characterized in that The Co-CeO according to claim 5 2 The Au loading mass is Co-CeO 2 The doped oxide is 0.01%-1% of the mass of the catalyst.

7. Au / Co-CeO 2 Method for preparing doped oxide catalyst, It is characterized in that The steps include: S21: Co-CeO 2 The doped oxide catalyst is uniformly dispersed in the chloroauric acid solution, stirred evenly at room temperature, and allowed to stand in the dark for 10-15 hours for aging; S22: The aged catalyst solution was dried in an oven at 70-90°C for 4-8 hours, placed in a muffle furnace, calcined at 500-600°C in an air atmosphere for 2-4 hours, and then naturally cooled to room temperature to obtain Au / Co-CeO 2 Doped oxide catalysts.

8. Use of the catalyst according to claim 5 or 6 in plasma catalytic oxidation purification of alkane organic volatile substances in the air.

9. The use according to claim 8, It is characterized in that The plasma intensity is between 0 and 50 J / L; the catalytic oxidation temperature is between room temperature and 100° C.; and it is suitable for plasma catalytic purification of organic volatile substances containing alkanes.

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