Catalyst, preparation method thereof and method for degrading plastic

Abstract

The invention relates to the technical field of catalysis, and discloses a catalyst, a preparation method thereof and a plastic degradation method. The catalyst satisfies xA.BO2, A is selected from one of Ni and Fe oxides, and B is selected from at least one of Ce and Zr; x is the mass ratio of A based on xA.BO2, and x is more than or equal to 5% and less than or equal to 90%. The catalyst can efficiently catalyze the pyrolysis process of waste plastics, so that the waste plastics are efficiently decomposed.

Description

Technical Field

[0001] This application relates to the field of catalysis technology, specifically to catalysts and their preparation methods, and methods for degrading plastics. Background Technology

[0002] Plastic products are durable and biodegradable; it takes 200 to 500 years for waste plastics to completely degrade in nature. The massive global use and rapid disposal of plastics has led to severe environmental pollution and resource waste. However, the recycling rate of waste plastics is low, only around 30%. Unrecycled waste plastics are disposed of through traditional incineration and landfill methods, which not only consume land resources but may also release harmful gases, placing a heavy burden on the environment. Therefore, developing efficient and environmentally friendly plastic waste treatment technologies is particularly important.

[0003] It should be noted that the above statements are only used to provide background information related to this application and do not necessarily constitute prior art. Summary of the Invention

[0004] In a first aspect of this application, a catalyst is proposed, wherein the catalyst satisfies: xA·BO2, wherein A is selected from Ni and Fe oxides, and B is selected from at least one of Ce and Zr; x is the mass percentage of A based on xA·BO2, 5%. <x<90%。

[0005] In some embodiments, A is selected from NiO and Fe2O3; and / or, the particle size of A is 8nm~12nm.

[0006] In some embodiments, the BO2 includes CeO2, ZrO2, or Ce 0.5 Zr 0.5 At least one of O2; and / or, the particle size of the BO2 is 20 nm to 30 nm.

[0007] In a second aspect of this application, a method for preparing the catalyst proposed in this application is provided, comprising: mixing a first metal salt, a second metal salt, and a stabilizer to obtain a precursor mixture, wherein the sum of the molar concentrations of the first metal salt and the second metal salt in the precursor mixture is 0.35 mol / L to 0.45 mol / L, the first metal salt comprising at least one of nickel and iron, and the second metal salt comprising at least one of cerium and zirconium; and subjecting the precursor mixture to atomization combustion treatment to obtain the catalyst.

[0008] In some embodiments, the method for preparing the catalyst proposed in this application satisfies at least one of the following conditions: the molar ratio of the first metal salt to the second metal salt is (1:5) to (5:1); the stabilizer includes at least one of 2-ethylhexanoic acid and polyvinyl alcohol.

[0009] In some embodiments, the method for preparing the catalyst proposed in this application satisfies at least one of the following conditions: the temperature of the atomization combustion treatment is 1600℃~1700℃; the flow rate of the atomized gas in the atomization combustion treatment is 12L / min~18L / min; and the feed rate of the precursor mixture in the atomization combustion treatment is 550mL / h~650mL / h.

[0010] In a third aspect of this application, a method for degrading plastics is proposed, using the catalyst proposed in this application or a catalyst prepared by the method proposed in this application, comprising: microwave catalytic treatment of the catalyst and waste plastics in water vapor at a mass ratio of 1:(1~5) to obtain degraded syngas.

[0011] In some embodiments, the mass flow rate of the water vapor is 30 g·h. -1 ·g -1 plastic ~150g·h -1 ·g -1 plastic ; and / or, the temperature of the microwave catalytic treatment is 400℃~800℃.

[0012] In some embodiments, the microwave power of the microwave catalytic treatment is 200W~1000W; and / or, the microwave frequency of the microwave catalytic treatment is 915MHz~5700MHz.

[0013] In some embodiments, the waste plastic includes at least one of polyethylene, polypropylene, and polystyrene; and / or, the degradation syngas includes at least one of hydrogen (H2), carbon monoxide (CO), methane (CH4), ethylene (C2H4), and ethane (C2H6).

[0014] The beneficial effects of the technical solution proposed in this application include at least the following: The catalytically active material in the catalyst proposed in this application can not only catalyze the pyrolysis process of waste plastics, enabling efficient decomposition of waste plastics; the material changes that occur during the catalytic process can effectively convert the solid carbon produced after the pyrolysis of waste plastics, transforming the solid carbon into other carbon-containing gases, thereby reducing the catalyst performance degradation caused by solid carbon coverage and extending the effective working life of the catalyst.

[0015] The syngas generated from the degradation of waste plastics using this catalyst is mainly composed of H2 and CO. Therefore, this syngas can be used as a raw material for the production of multipurpose fuels and chemical intermediates (such as methanol and ethanol), and as an alternative to the high-temperature, high-pressure dry or wet reforming of fossil fuels to produce syngas. This provides a technical route for producing syngas from waste plastics rather than fossil reserves, which can play a role in recycling plastic waste and protecting fossil resources. Attached Figure Description

[0016] The above and / or additional aspects and advantages of this application will become apparent and readily understood from the description of the embodiments taken in conjunction with the following drawings, in which: Figure 1 The images shown are transmission electron microscope (TEM) images and X-ray energy dispersive spectroscopy (EDS) images of the catalysts in the embodiments of this application, wherein (a, b) are TEM images of NiCeO, (c, d) are TEM images of NiZrO, (e, f) are TEM images of NiCeZrO, (g, h) are TEM images of FeCeZrO; and (i~l) are EDS images of NiCeZrO. Figure 2 The X-ray diffraction pattern (XRD pattern) of the catalyst in one embodiment of this application is shown. Figure 3 This is a scanning electron microscope (SEM) image of the carbon nanotubes generated in Example 1 of this application. Detailed Implementation

[0017] The embodiments of this application are described in detail below, with examples of these embodiments shown in the accompanying drawings. However, unnecessary detailed descriptions may be omitted. For example, detailed descriptions of well-known matters and repetitive descriptions of practically identical structures may be omitted. This is to avoid unnecessarily lengthy descriptions and to facilitate understanding by those skilled in the art. Furthermore, the accompanying drawings and the following description are provided to enable those skilled in the art to fully understand this application and are not intended to limit the subject matter of the claims.

[0018] Unless otherwise defined, all technical and scientific terms used in this application have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains; the terminology used in this application is for the purpose of describing particular embodiments only and is not intended to limit this application; unless otherwise stated, the values ​​of the parameters mentioned in this application can be measured using various measurement methods commonly used in the art (e.g., they can be tested according to the methods given in the embodiments of this application).

[0019] The terms “comprising” and “having”, and any variations thereof, in the specification and claims of this application are open-ended expressions, meaning they include what is specified in this application but do not exclude other aspects.

[0020] In the description of this application, all figures disclosed herein, whether or not the words "approximately" or "about" are used, are approximate values. Each figure may vary by less than 10% or by a difference that is considered reasonable by one of the art, such as 1%, 2%, 3%, 4%, or 5%.

[0021] The "range" disclosed in this application is defined by a lower limit and an upper limit. A given range is defined by selecting a lower limit and an upper limit, which define the boundaries of a particular range. Ranges defined in this way can include or exclude endpoints and can be arbitrarily combined; that is, any lower limit can be combined with any upper limit to form a range. For example, if ranges of 60~120 and 80~110 are listed for a specific parameter, it is also expected that ranges of 60~110 and 80~120 are also included. Furthermore, if minimum range values ​​of 1 and 2 are listed, and if maximum range values ​​of 3, 4, and 5 are listed, then the following ranges are all expected: 1~3, 1~4, 1~5, 2~3, 2~4, and 2~5. In this application, unless otherwise stated, the numerical range "a~b" represents a shortened representation of any combination of real numbers between a and b, where a and b are real numbers. For example, the numerical range "0~5" indicates that all real numbers between "0~5" have been listed in this article; "0~5" is simply a shortened representation of these numerical combinations. Furthermore, when a parameter is stated as an integer ≥2, it is equivalent to disclosing that the parameter is, for example, an integer such as 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, etc.

[0022] Unless otherwise specified, all embodiments and optional embodiments of this application can be combined to form new technical solutions.

[0023] Unless otherwise specified, all technical features and optional technical features of this application may be combined to form new technical solutions.

[0024] Among the technologies related to waste plastic recycling, microwave catalytic pyrolysis technology, as a novel recycling technology, can absorb microwave energy through a catalyst, enabling waste plastics to pyrolyze under microwave radiation. This produces hydrocarbon products with extremely high efficiency while leaving abundant solid carbon. It boasts advantages such as rapid heating, high energy utilization, and easy control of reaction conditions. Using this technology can increase the conversion rate of waste plastics, reduce recycling processing time and operating temperature, thereby improving the selectivity and yield of recycled products.

[0025] However, in existing microwave catalytic pyrolysis technologies, solid carbon generated from the pyrolysis of waste plastics can deposit on the catalyst surface, hindering the contact between subsequent reactants and the active sites on the catalyst. This severely affects the catalyst's performance and impedes the recycling of waste plastics. Catalysts coated with solid carbon are often separated from the catalyst using surface washing methods such as acid treatment. These surface washing methods can cause irreversible damage to the catalyst, affecting its catalytic performance or preventing its recycling.

[0026] This application discloses a catalyst and a method for degrading plastics using the catalyst. The catalytically active material in the catalyst not only catalyzes the pyrolysis of waste plastics, enabling efficient decomposition, but also effectively converts the solid carbon produced after the pyrolysis of waste plastics into other carbon-containing gases through a material transformation process. This reduces catalyst performance degradation caused by solid carbon coverage and extends the effective working life of the catalyst.

[0027] In a first aspect of this application, a catalyst is proposed that satisfies: xA·BO2, wherein A is selected from one of Ni and Fe oxides, and B is selected from at least one of Ce and Zr; x is the mass percentage of A based on xA·BO2, and 5% ≤ x < 90%.

[0028] The catalyst proposed in this application utilizes BO2 as an active site carrier to provide fixed sites for the catalytically active substance A, resulting in relatively stable catalyst performance. A is selected from Ni and Fe oxides, with their mass percentages within the aforementioned range. Nanoscale nickel-based or iron-based oxides, as the catalytically active substance, effectively absorb microwave energy and convert it into heat energy, providing the energy required for the catalytic change. Plastics (such as polyethylene) are inherently microwave-transparent, but through physical mixing with a catalyst possessing strong microwave absorption capabilities, the high temperature generated by the catalyst's absorption of microwaves can induce changes in their molecular chain structure, thereby degrading the plastic material. The degradation syngas generated from waste plastics degraded using this catalyst mainly consists of H2 and CO. Therefore, this degradation syngas can serve as a raw material syngas for producing multi-purpose fuels and chemical intermediates (such as methanol and ethanol), and as an alternative to the high-temperature, high-pressure dry or wet reforming of fossil fuels to produce syngas. This provides a technical route for producing syngas from waste plastics rather than fossil reserves, playing a role in recycling plastic waste and protecting fossil resources.

[0029] As an example, x is 5%, 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, or 90%.

[0030] In some embodiments, A is selected from NiO and Fe2O3; and / or, the particle size of A is 8 nm to 12 nm. Therefore, the aforementioned A has a good ability to absorb microwave energy in the catalyst, and its particle size within the aforementioned range is beneficial for a more uniform distribution in the catalyst, thereby improving the catalytic activity of the catalyst and reducing the impact of product accumulation on catalytic activity during the catalytic process.

[0031] In some embodiments, the BO2 includes CeO2, ZrO2, or Ce 0.5 Zr 0.5 At least one of O2; and / or, the BO2 has a particle size of 20 nm to 30 nm. Therefore, the aforementioned BO2 has a large specific surface area, and its particle size, within the aforementioned range, allows for effective spatial combination with the metal oxide A. This is beneficial for the distribution of active sites and increases the reaction rate of the catalytic reaction.

[0032] As examples, catalysts include x(NiO)·CeO2, x(NiO)·ZrO2, and x(NiO)·CeO2. 0.5 Zr 0.5 O2 or x(Fe2O3)·Ce 0.5 Zr 0.5 O2 can be denoted as NiCeO, NiZrO, NiCeZrO, and FeCeZrO, respectively.

[0033] As an example, the particle size of the BO2 is 20nm, 22nm, 25nm, 28nm or 30nm.

[0034] In a second aspect of this application, a method for preparing the catalyst proposed in this application is provided, comprising: mixing a first metal salt, a second metal salt, and a stabilizer to obtain a precursor mixture, wherein the sum of the molar concentrations of the first metal salt and the second metal salt in the precursor mixture is 0.35 mol / L to 0.45 mol / L, the first metal salt comprising at least one of nickel and iron, and the second metal salt comprising at least one of cerium and zirconium; and subjecting the precursor mixture to atomization combustion treatment to obtain the catalyst.

[0035] The method for preparing the catalyst proposed in this application utilizes a swirling atomizing flame during the atomization combustion process to induce the formation of multi-component composite metal oxide nanoparticles from metal ions in the precursor mixture. This allows for the efficient and stable conversion of metal ions in the precursor mixture into nanoscale catalysts with uniform particle size and high purity.

[0036] In some embodiments, the method for preparing the catalyst proposed in this application satisfies at least one of the following conditions: the molar ratio of the first metal salt to the second metal salt is (1:5) to (5:1); the stabilizer includes at least one of 2-ethylhexanoic acid and polyvinyl alcohol. The molar ratio of the first metal salt to the second metal salt affects the mass ratio of nickel, iron oxides and cerium, zirconium oxides in the catalyst, and the aforementioned stabilizer is beneficial to the stable conversion of metal elements in the precursor mixture during the atomization combustion process. Therefore, this method is advantageous for the efficient and high-yield preparation of catalysts with controllable composition and stable catalytic performance.

[0037] In some embodiments, the method for preparing the catalyst proposed in this application satisfies at least one of the following conditions: the temperature of the atomization combustion treatment is 1600℃~1700℃; the flow rate of the atomized gas in the atomization combustion treatment is 12L / min~18L / min; and the feed rate of the precursor mixture in the atomization combustion treatment is 550mL / h~650mL / h. Within the aforementioned parameter range, the atomized gas in the atomization combustion treatment can provide relatively stable combustion conditions for the atomized flame, thereby converting metal ions in the incoming precursor mixture into nanoscale metal oxides and completing the composite of multiple metal oxides. This facilitates the efficient preparation of the catalyst proposed in this application.

[0038] In a third aspect of this application, a method for degrading plastics is proposed, using the catalyst proposed in this application or a catalyst prepared by the method proposed in this application, comprising: microwave catalytic treatment of the catalyst and waste plastics in water vapor at a mass ratio of 1:(1~5) to obtain degraded syngas.

[0039] This method for degrading plastics employs a catalyst, as described in this application, using nickel-based or iron-based nanomaterials as the active catalyst. Microwaves are used as the energy input for the catalytic reaction, causing the molecular chains of the waste plastic to break down and degrade. Thus, with the aid of the catalyst, the waste plastic is decomposed into degradation syngas containing H2, CO, and small amounts of methane (CH4), ethylene (C2H4), and ethane (C2H6).

[0040] During the degradation of plastics, the catalyst rapidly absorbs microwave energy and heats up, quickly generating localized high temperatures on its surface. Waste plastics (such as polyethylene) are themselves microwave-transparent, but through physical mixing with a strong microwave absorber (catalyst), the high temperatures generated by the catalyst promote plastic degradation. After absorbing energy, the carbon skeleton of the long-chain polymers in waste plastics undergoes homolytic cleavage of the C-C bonds and CH bonds, producing a large amount of alkane and olefin fragments and free radicals (such as ·H, ·CH3, ·C2H5, etc.). These olefin fragments can further undergo β-cleavage, disproportionation, and recombination reactions to generate a mixed gas rich in hydrogen (H2), methane (CH4), ethylene (C2H4), ethane (C2H6), and gaseous hydrocarbons with higher carbon numbers. The gaseous hydrocarbons produced by the dehydrogenation decomposition of waste plastics can react with water vapor on the catalyst to further produce H2 and CO.

[0041] Furthermore, the strong reducing atmosphere created during the catalytic reaction (provided by hydrogen and hydrocarbons generated from plastic cracking) and the high temperature, along with the metal ions (such as Ni) in the catalytically active metal oxide, contribute to the catalytic reaction. 2+ The waste plastic (PC) is partially or completely reduced to its metallic state. The resulting gaseous hydrocarbons (such as CH4 and C2H4) diffuse onto the surface of the metallic nanoparticles, where they are adsorbed and further catalytically decomposed into carbon atoms and hydrogen. Therefore, during catalytic degradation, the degradation products undergo a reforming reaction with water vapor, reducing carbon buildup on the catalyst caused by the decomposition of waste plastics. This reduces the decrease in catalyst activity caused by carbon buildup, improves catalyst durability, and extends catalyst lifespan, allowing the catalytic reaction of plastic degradation to continue. This method is simple and can efficiently catalytically reform waste plastics into degraded syngas, a multi-purpose raw material, and the catalytic reaction can continue, thus showing broad prospects for promotion and practical application.

[0042] In some embodiments, the mass flow rate of the water vapor is 30 g·h. -1 ·g -1 plastic ~150g·h -1 ·g -1 plastic ; and / or, the temperature of the microwave catalytic treatment is 400℃~800℃. Therefore, the aforementioned conditions provide a superior catalytic environment for the catalyst, which is beneficial for improving the treatment efficiency of plastic degradation.

[0043] In some embodiments, the microwave power of the microwave catalytic treatment is 200W~1000W; and / or, the microwave frequency of the microwave catalytic treatment is 915MHz~5700MHz. Therefore, the aforementioned microwave conditions are beneficial for improving the catalytic performance and catalytic efficiency of the catalyst.

[0044] In some embodiments, the waste plastic includes at least one of polyethylene, polypropylene, and polystyrene; and / or, the degradation syngas includes at least one of hydrogen (H2), carbon monoxide (CO), methane (CH4), ethylene (C2H4), and ethane (C2H6).

[0045] The following specific embodiments illustrate the solution of this application. It should be noted that these embodiments are for illustrative purposes only and should not be considered as limiting the scope of this application. Where specific techniques or conditions are not specified in the embodiments, they are performed according to the techniques or conditions described in the literature in this field or according to the product instructions. Reagents or instruments whose manufacturers are not specified are all conventional products that can be obtained commercially.

[0046] Example 1 NiCeZrO catalyst preparation process: A solution of nickel nitrate, cerium nitrate, and zirconium nitrate was prepared in a molar ratio of 1:1.12:1.12. A stabilizer was added and the mixture was further treated to obtain a precursor mixture. The sum of the molar concentrations of the metal salts in the precursor mixture was 0.4 mol / L. The precursor mixture was then subjected to atomization combustion treatment to obtain the catalyst. The temperature of the atomization combustion treatment was controlled at 1600℃~1700℃; the flow rate of the atomized gas was 15 L / min; and the feed rate of the precursor mixture was 600 mL / h.

[0047] Waste polyethylene (PE) with a molecular weight of 40,000 to 300,000 was mixed with NiCeZrO catalyst at a mass ratio of 1:1 and placed into a quartz tube. The quartz tube was then connected to a microwave reactor, and nitrogen gas was introduced to purge the air out of the reactor. The microwave power was adjusted to 1000 W and the operating frequency was 2450 MHz, and the mixture was held for 120 s.

[0048] Collect 1.45 L·g of gas -1 plastic 596.5 mg·g of carbon solids -1 plastic The carbon solid is composed of carbon nanotubes with a diameter of approximately 15 nm, see [link / reference]. Figure 3 The gas composition is shown in Table 1.

[0049] Example 2 Example 2 is the same as Example 1, except that water and waste plastic are added to the reactor, and the mass flow rate of the water vapor is 30 g / h. -1 g -1 plastic .

[0050] Collect 2.10 L·g of gas -1plastic The gas composition is shown in Table 1.

[0051] Example 3 Example 3 is the same as Example 2, except that the mass flow rate of the water vapor is 60 g / h. -1 g -1 plastic .

[0052] Collected gas 2.70 L·g -1 plastic The gas composition is shown in Table 1.

[0053] Example 4 Example 4 is the same as Example 2, except that the mass flow rate of the water vapor is 90 g·h. -1 ·g -1 plastic .

[0054] Collected gas 3.65 L·g -1 plastic The gas composition is shown in Table 1.

[0055] Example 5 Example 5 is the same as Example 4, except that a NiCeO catalyst is used.

[0056] The preparation process of NiCeO catalyst is as follows: Nickel nitrate and cerium nitrate are mixed in a molar ratio of 1:1.84, and a stabilizer is added for further mixing to obtain a precursor mixture. The sum of the molar concentrations of the metal salts in the precursor mixture is 0.4 mol / L. The precursor mixture is then subjected to atomization combustion treatment to obtain the catalyst. The temperature of the atomization combustion treatment is controlled at 1600℃~1700℃; the flow rate of the atomized gas is 15 L / min; and the feed rate of the precursor mixture is 600 mL / h.

[0057] Collect 3.30 L·g of gas -1 plastic The gas composition is shown in Table 1.

[0058] Example 6 Example 6 is the same as Example 4, except that a NiZrO catalyst is used.

[0059] The preparation process of the NiZrO catalyst is as follows: Nickel nitrate and zirconium nitrate are mixed in a molar ratio of 1:2.57, and a stabilizer is added for further mixing to obtain a precursor mixture. The sum of the molar concentrations of the metal salts in the precursor mixture is 0.4 mol / L. The precursor mixture is then subjected to atomization combustion treatment to obtain the catalyst. The atomization combustion temperature is approximately 1600℃~1700℃; the atomization gas flow rate is 15 L / min; and the precursor mixture feed rate is 600 mL / h.

[0060] Collect 1.75 L·g of gas -1 plastic The gas composition is shown in Table 1.

[0061] Example 7 Example 7 is the same as Example 4, except that it uses a FeCeZrO catalyst.

[0062] Preparation process of FeCeZrO catalyst: Collect 3.15 L·g of gas -1 plastic The gas composition is shown in Table 1.

[0063] Example 8 Waste plastics were mixed evenly with the reaction products from Example 1 (including the catalyst and solid carbon products after the reaction) at a mass ratio of 1:1 and placed into a quartz tube. Water and waste plastics were added to the reactor at a mass ratio of 5:1, and the mass flow rate of the water vapor was 150 g / h. -1 g -1 plastic A quartz tube was connected to the microwave reactor, and nitrogen gas was introduced to purge the reactor and remove all air. The microwave power was adjusted to 1000W, the operating frequency was 2450 MHz, and the setting was maintained for 120 seconds. The gas was collected, yielding 4.50 L·g. -1 plastic The gas composition is shown in Table 1. In this way, the carbon products generated in Example 1 can be effectively removed.

[0064] Example 9 Example 9 is consistent with Example 4, except that the mass ratio of waste plastic to NiCeZrO catalyst is 2:1. 3.40 L·g of gas was collected. -1 plastic The gas composition is shown in Table 1.

[0065] Example 10 Example 10 is consistent with Example 4, except that the mass ratio of waste plastic to NiCeZrO catalyst is 3:1. 3.05 L·g of gas was collected.-1 plastic The gas composition is shown in Table 1.

[0066] Test method: The collected gas was passed into a gas chromatograph to obtain the ratio of hydrogen to carbon monoxide in the gas. Based on the ratio of gas components, the hydrogen yield and carbon monoxide yield per gram of plastic were calculated.

[0067] Test results: See Table 1.

[0068] Table 1

[0069] In the description of this application, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. "First feature" and "second feature" may include one or more of the indicated feature.

[0070] In the description of this application, "multiple" means two or more.

[0071] In the description of this application, "A and / or B" can include any of the cases of A alone, B alone, or A and B, where A and B are merely examples and can be any technical feature connected by "and / or" in this application.

[0072] In this application, the order in which the steps are written does not imply a strict execution order and does not limit the implementation process. The specific execution order of each step should be determined by its function and possible internal logic. Unless otherwise specified, all steps in this application can be performed sequentially or randomly, preferably sequentially. For example, if the method includes steps (a) and (b), it means that the method may include steps (a) and (b) performed sequentially, or it may include steps (b) and (a) performed sequentially. For example, if the method may also include step (c), it means that step (c) can be added to the method in any order. For example, the method may include steps (a), (b), and (c), or it may include steps (a), (c), and (b), or it may include steps (c), (a), and (b), etc.

[0073] It should be noted that this application is not limited to the above-described embodiments. The above embodiments are merely examples, and any embodiments with the same structure and effect as the technical concept within the scope of this application are included in the technical scope of this application. Furthermore, various modifications that can be conceived by those skilled in the art to the embodiments, and other ways of constructing by combining some of the constituent elements of the embodiments, without departing from the spirit of this application, are also included in the scope of this application.

Claims

1. A catalyst, characterized in that, The catalyst satisfies: xA·BO2, where A is selected from Ni or Fe oxide, and B is selected from at least one of Ce or Zr; x is the mass percentage of A based on xA·BO2, where 5% ≤ x < 90%.

2. The catalyst according to claim 1, characterized in that, A is selected from NiO and Fe2O3; and / or, The particle size of A is 8nm~12nm.

3. The catalyst according to claim 1, characterized in that, The BO2 includes CeO2, ZrO2, or Ce 0.5 Zr 0.5 At least one of O2; and / or, The particle size of the BO2 is 20nm~30nm.

4. A method for preparing the catalyst according to any one of claims 1 to 3, characterized in that, include: A first metal salt, a second metal salt, and a stabilizer are mixed to obtain a precursor mixture, wherein the sum of the molar concentrations of the first metal salt and the second metal salt in the precursor mixture is 0.35 mol / L to 0.45 mol / L, the first metal salt includes at least one of nickel and iron, and the second metal salt includes at least one of cerium and zirconium. The precursor mixture is subjected to atomization and combustion treatment to obtain the catalyst.

5. The method according to claim 4, characterized in that, At least one of the following conditions must be met: The molar ratio of the first metal salt to the second metal salt is (1:5) to (5:1); The stabilizer includes at least one of 2-ethylhexanoic acid and polyvinyl alcohol.

6. The method according to claim 4, characterized in that, At least one of the following conditions must be met: The temperature of the atomization combustion treatment is 1600℃~1700℃; The flow rate of the atomized gas in the atomization combustion treatment is 12 L / min to 18 L / min; The feed rate of the precursor mixture for atomized combustion treatment is 550 mL / h to 650 mL / h.

7. A method for degrading plastics, characterized in that, The catalyst prepared using the catalyst according to any one of claims 1 to 3 or the method according to any one of claims 4 to 6 comprises: The catalyst and waste plastics were subjected to microwave catalytic treatment in steam at a mass ratio of 1:(1~5) to obtain degradation syngas.

8. The method according to claim 7, characterized in that, The mass flow rate of the water vapor is 30 g·h -1 ·g -1 plastic ~150g·h -1 ·g -1 plastic ; and / or, The temperature of the microwave catalytic treatment is 400℃~800℃.

9. The method according to claim 7, characterized in that, The microwave power of the microwave catalytic treatment is 200W~1000W; and / or, The microwave frequency of the microwave catalytic treatment is 915MHz~5700MHz.

10. The method according to any one of claims 7 to 9, characterized in that, The waste plastics include at least one of polyethylene, polypropylene, and polystyrene; and / or, The degradation synthesis gas includes at least one of hydrogen, carbon monoxide, methane, ethylene, and ethane.

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