Metal atom catalyst based on ionization irradiation in-situ synthesis and synthesis method

Abstract

The invention provides a metal atom catalyst based on ionization irradiation in-situ synthesis and a synthesis method, and the synthesis method comprises the following synthesis steps: adding a catalyst carrier and a metal salt into an ethanol solution, stirring at 50-70 DEG C for 1-4 h, and then filtering out a solid; carrying out vacuum drying treatment on the solid, then mixing the solid with a proper amount of isopropanol and deionized water in a centrifugal tube, discharging air in the centrifugal tube, and carrying out irradiation treatment with the irradiation dose rate of 0.4-1.0 kGy / h and the irradiation time of 6-25 h; and carrying out suction filtration on the mixed system subjected to irradiation treatment, and carrying out washing and vacuum drying treatment on the obtained solid to finally obtain the metal atom catalyst. The synthesis process provided by the invention is simple in process flow and low in cost, the dose required by irradiation is greatly reduced, in the prepared metal atom catalyst, the dispersion degree and the loading capacity of metal monoatoms are high, and an economical and effective method capable of realizing large-scale production is provided for synthesis of the carbon-loaded multi-metal atom catalyst.

Description

Technical Field

[0001] The present invention relates to the technical field of catalysts and preparation thereof, and in particular to a metal atom catalyst synthesized in situ based on ionizing radiation and a synthesis method thereof. Background Art

[0002] Advanced oxidation technology can effectively remove or even mineralize refractory organic pollutants in water bodies by virtue of the active species it produces, and has broad application prospects in the field of water treatment. The treatment effect of advanced oxidation technology depends on heterogeneous catalysts. Up to now, the heterogeneous catalysts that can be used for advanced oxidation technology reported in research can be divided into carbon materials, carbon-based materials, metal compounds, etc. Among them, carbon-supported metal atom catalysts have received widespread attention in the field of environmental catalysis due to their high metal atom utilization rate and excellent catalytic activity. In order to overcome the problem of fewer metal active sites in carbon-supported metal atom catalysts, scholars have developed carbon-supported multi-metal atom catalysts, which on the one hand increase the number of metal active sites, and on the other hand utilize the interaction between metals to improve the catalytic stability of carbon-supported metal atom catalysts.

[0003] At present, the methods commonly used to prepare carbon-supported metal atom catalysts include chemical deposition, pyrolysis and photocatalytic synthesis. However, these methods have certain drawbacks, which limit the practical application of carbon-supported metal single atoms. For example, pyrolysis is currently the most widely used method for synthesizing carbon-supported metal atom catalysts. However, the temperature required for pyrolysis is high, and it is difficult to achieve uniform distribution of metal single atoms during the pyrolysis process due to the mutual attraction between metal single atoms. When synthesizing multi-metal atom catalysts, complex precursors are usually required to complex different metal ions, and then pyrolysis treatment is performed. During the pyrolysis process, the occurrence of metal ion agglomeration cannot be avoided, resulting in some metal ions forming metal nanoclusters or metal nanoparticles. How to reduce the temperature required for the preparation of carbon-supported metal atom catalysts, avoid the agglomeration of metal ions during the preparation process, and make the metal ions evenly distributed is the key to whether carbon-supported metal atom catalysts can be promoted and applied in the field of water treatment.

[0004] Ionizing radiation refers to radiation that carries enough energy to free the electrons in the atoms or molecules of a substance, thereby causing these atoms or molecules to ionize. At present, ionizing radiation technology has been widely used in food disinfection and sterilization and material modification. When ionizing radiation acts on water, it will cause water molecules to undergo radiolysis to produce active species such as hydroxyl radicals, hydrated electrons and hydrogen radicals. When other ions, such as metal ions, exist in the water, these active species can interact with the metal ions, causing the metal ions to undergo oxidation or reduction. Therefore, ionizing radiation can be used to synthesize carbon-supported metal atom catalysts.

[0005] However, the existing ionizing radiation method for preparing carbon-supported metal atom catalysts still has problems such as easy aggregation of metal single atoms, low dispersion, unstable loading, and the large amount of organic solvents used in the preparation process, resulting in low preparation efficiency and resource utilization. Summary of the invention

[0006] In view of the above problems existing in the prior art, the present invention provides a metal atom catalyst and a synthesis method based on in-situ synthesis by ionizing radiation to solve the problems in the prior art that metal single atoms are easy to aggregate during the reduction process, the dispersion is not high, and the loading amount is unstable.

[0007] The specific content of the invention is as follows: In a first aspect, the present invention provides a method for in-situ synthesis of metal atom catalysts based on ionizing radiation, the method comprising the following steps: S1. Add the catalyst support and the metal salt to an ethanol solution, stir at 50°C to 70°C for 1 to 4 hours, and then filter out the solid, wherein the mass ratio of the catalyst support to the metal ion in the metal salt is 100:9-30; S2, vacuum drying the solid, then mixing it with an appropriate amount of isopropanol and deionized water in a centrifuge tube, exhausting the air in the centrifuge tube, and then irradiating it, with an irradiation dose rate of 0.4-1.0 kGy / h and an irradiation time of 6-25 h; S3, filtering the mixed system after irradiation, washing the obtained solid, and vacuum drying it to finally obtain the metal atom catalyst; The catalyst carrier is a nitrogen-doped carbon material; The metal salt comprises soluble salts containing iron, cobalt, nickel, manganese or copper, or at least two of the soluble salts containing iron, cobalt, nickel, manganese and copper are mixed in any proportion.

[0008] Optionally, the mass volume ratio of the catalyst carrier to the ethanol solution is 100 mg: 50-70 mL; The mass volume ratio of the catalyst carrier to the isopropanol is 100 mg: 1.5-2.0 μL.

[0009] Optionally, the vacuum drying treatment is carried out at a temperature of 40 to 60° C. and for a time of 6 to 12 h.

[0010] Optionally, the radiation source of the irradiation treatment is an electron accelerator, 60 Co or 137 Cs.

[0011] Optionally, the temperature controlled by the constant temperature stirring is 60°C.

[0012] Optionally, the washing includes: washing the obtained solid with deionized water for 1-5 times.

[0013] Optionally, the catalyst carrier is graphite-phase carbon nitride, and the metal salt is at least one of CuCl2, FeCl3·6H2O and CoCl2·6H2O.

[0014] Optionally, the irradiation dose rate is 0.5-18 kGy / h, and the irradiation time is 8-10 h.

[0015] Optionally, exhausting the air in the centrifuge tube includes: introducing nitrogen into the centrifuge tube for 15-30 s to exhaust the air in the centrifuge tube.

[0016] In a second aspect, the present invention provides a metal atom catalyst obtained by the method for in-situ synthesis of metal atom catalysts based on ionizing radiation as described in the first aspect.

[0017] Compared with the prior art, the present invention has the following advantages: The present invention provides a method for in-situ synthesis of metal atom catalysts based on ionizing radiation, the method comprising the following steps: S1, adding a catalyst carrier and a metal salt to an ethanol solution, stirring at 50°C to 70°C for 1 to 4 hours, and then filtering out a solid; S2, vacuum drying the solid, then mixing it with an appropriate amount of isopropanol in a centrifuge tube, exhausting the air in the centrifuge tube, and then irradiating it, the irradiation dose rate is 0.4 to 1.0 kGy / h, and the irradiation time is 6 to 25 hours; S3, suction filtering the mixed system after irradiation, washing the obtained solid, and vacuum drying it to finally obtain the metal atom catalyst; wherein the catalyst carrier is carbon nitride, an inorganic molecular sieve, porous alumina or porous carbon; the metal salt comprises one of soluble salts of iron, cobalt, nickel, manganese and copper, or a plurality of salts mixed in any proportion.

[0018] In the synthesis method provided by the present invention, when performing the task of mixing the catalyst support and the metal salt, ethanol is directly used as a solvent for mixing. Ethanol as a solvent can not only promote the dissolution of the metal salt, but also provide a uniform dispersion environment for the catalyst support material, so that the catalyst support and the metal salt are fully dissolved and dispersed, and the metal ions are prevented from agglomerating in the irradiation reduction process in the later stage; in addition, after the irradiation object is mixed with isopropanol, the irradiation system containing isopropanol is irradiated. Isopropanol, as a reducing agent, can help the metal salt to be reduced to metal atoms. And because metal atoms are easy to aggregate during the formation process, the present invention provides a certain steric hindrance for the reduction of metal atoms on the catalyst support with the help of isopropanol, thereby reducing the aggregation tendency of metal atoms and promoting the formation of metal atom catalysts. More importantly, the presence of isopropanol enables the metal salt to obtain a certain fluidity during the irradiation process, which helps to increase the loading amount of metal atoms on the catalyst support. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] 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 or the description of the prior art 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.

[0020] Figure 1 A flow chart of a method for in-situ synthesis of metal atom catalysts based on ionizing radiation provided by an embodiment of the present invention is shown.

[0021] Figure 2 The spherical aberration electron microscope image of the in-situ synthesis of metal atom catalysts based on ionizing radiation provided in Example 1 of the present invention is shown; Figure 3 The spherical aberration electron microscope image of the in-situ synthesis of metal atom catalysts based on ionizing radiation provided in Example 2 of the present invention is shown; Figure 4 The spherical aberration electron microscope image of the in-situ synthesis of metal atom catalysts based on ionizing radiation provided in Example 3 of the present invention is shown; Figure 5 The spherical aberration electron microscope image of the in-situ synthesis of metal atom catalyst based on ionizing radiation provided in Example 4 of the present invention is shown. DETAILED DESCRIPTION

[0022] The technical solutions in the embodiments of the present invention will be described clearly and completely below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, not all of the embodiments. The following description of at least one exemplary embodiment is actually only illustrative and is by no means a limitation on the present invention and its application or use. Based on the embodiments of the present invention, any product identical or similar to the present invention obtained by anyone under the inspiration of the present invention or by combining the features of the present invention with other prior arts falls within the scope of protection of the present invention. In addition, all other embodiments obtained by ordinary technicians in this field without carrying out creative work belong to the scope of protection of the present invention.

[0023] In the embodiment, no specific experimental steps or conditions are indicated, and the operation or conditions of the conventional experimental steps described in the prior art in this field can be carried out. The reagents used and other instruments that do not indicate the manufacturer are conventional reagent products that can be obtained commercially. In addition, the accompanying drawings are only schematic diagrams of the embodiments of the present invention and are not necessarily drawn to scale. The same reference numerals in the figures represent the same or similar parts, and thus their repeated description will be omitted. Some block diagrams shown in the accompanying drawings are functional entities and do not necessarily correspond to physically or logically independent entities.

[0024] Technologies, methods, and equipment known to ordinary technicians in the relevant field may not be discussed in detail, but where appropriate, the technologies, methods, and equipment should be considered as part of the description of the present invention.

[0025] In the description of the present invention, it should be understood that the use of terms such as "first" and "second" to limit components is only for the convenience of distinguishing the corresponding components. Unless otherwise stated, the above terms have no special meaning and therefore cannot be understood as limiting the scope of protection of the present invention.

[0026] In addition, the technical features involved in the different embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0027] Before describing in detail the metal atom catalyst and synthesis method based on in-situ synthesis by ionizing radiation provided by the present invention, it is necessary to describe the related technologies as follows: The patent (CN 112691689 B) discloses a steam irradiation reduction synthesis method for metal atom catalysts. In the invention, the catalyst carrier and the noble metal catalyst are first stirred and dispersed in an aqueous solution, and the pH of the solution is adjusted to 10. The resulting solution is then freeze-dried, and the freeze-dried solid fully absorbs ethanol vapor in an ethanol vapor environment. The catalyst is then irradiated with a gamma radiation source under inert atmosphere conditions, with an irradiation dose of 100 kGy, and a highly dispersed metal atom catalyst is finally obtained. Although the patent finally synthesized a highly dispersed metal atom catalyst, the pretreatment process before irradiation is complicated, requiring the catalyst carrier and the noble metal catalyst to be mixed in an alkaline environment. The irradiation process is also required to be carried out in an inert gas environment, and the irradiation dose required is high, resulting in high costs.

[0028] The patent (CN 108906113 A) provides a method for synthesizing a high-loaded noble metal atom catalyst by ultraviolet irradiation. In the invention, the nitrogen-doped carbon material is first mixed with a quantitative noble metal acid or salt to fully adsorb the metal ions, then dried and then irradiated with ultraviolet light to obtain the noble metal atom catalyst. Although the method obtains a noble metal atom catalyst, the loading amount is only between 0.13 wt.% and 9.8 wt.%, and the noble metal is prone to agglomeration during the preparation process, that is, the dispersion of the metal single atoms is uneven.

[0029] Based on this, the present invention proposes a metal atom catalyst and a synthesis method based on in-situ synthesis by ionizing radiation. The process is simple and low in cost, greatly reducing the required dose of radiation. The prepared metal atom catalyst has high metal single atom dispersion and loading, providing an economical and effective method for the synthesis of carbon-supported multi-metal atom catalysts that can be scaled up for mass production. The specific implementation content is as follows: In a first aspect, the present invention provides a method for in-situ synthesis of metal atom catalysts based on ionizing radiation, the method comprising the following steps: S1. Add the catalyst support and the metal salt into the ethanol solution, stir at 50°C to 70°C for 1 to 4 h, and then filter out the solid; In this step, when performing the task of mixing the catalyst carrier and the metal salt, ethanol is directly used as a solvent for mixing. Ethanol as a solvent can not only promote the dissolution of the metal salt, but also provide a uniform dispersion environment for the catalyst carrier material; stirring for 1 to 4 hours at a constant temperature of 50°C to 70°C is conducive to the dissolution of the metal salt and the dispersion of the catalyst carrier material, thereby promoting the formation of a uniform distribution of metal atoms in the metal atom catalyst. The preferred stirring temperature is 60°C.

[0030] In a specific implementation, the catalyst carrier can be selected from nitrogen-doped carbon materials; the composition of the metal salt includes soluble salts containing iron, cobalt, nickel, manganese or copper, or at least two of the soluble salts containing iron, cobalt, nickel, manganese and copper are mixed in any proportion. As a preferred example, the catalyst carrier can be graphite phase carbon nitride, and the metal salt is selected from at least one of CuCl2, FeCl3·6H2O and CoCl2·6H2O.

[0031] It should be noted that in the process of adding the catalyst carrier and the metal salt to the ethanol solution, the mass ratio of the metal ions in the selected catalyst carrier and the metal salt is controlled at 100:9-30; the amount of ethanol solution used is preferably enough to submerge the catalyst carrier and the metal salt. As an example, the mass volume ratio of the catalyst carrier to the ethanol solution can be controlled at 100 mg:50-70 mL.

[0032] S2, vacuum drying the solid, then mixing it with an appropriate amount of isopropanol and deionized water in a centrifuge tube, exhausting the air in the centrifuge tube, and then irradiating it, with an irradiation dose rate of 0.4-1.0 kGy / h and an irradiation time of 6-25 h; After the treatment in step S1, the catalyst carrier and the metal salt are fully dissolved and dispersed in the ethanol solution, and the solid material obtained by filtration is formed by the catalyst carrier and the metal salt infiltrated into the surface and pores of the carrier. The obtained solid material is vacuum dried to remove ethanol and excess water, and the temperature of the vacuum drying treatment is 40-60 ° C, and the time is 6-12 hours; then, an appropriate amount of isopropanol solution is added to the solid material after vacuum drying, and irradiation treatment is performed. Isopropanol first acts as a hydroxyl radical quencher formed in the irradiation system, quenching the hydroxyl radicals generated in the irradiation system, and creating a system dominated by reducing active particles; on the other hand, the alcohol radicals formed after the quenching of the hydroxyl radicals by propanol also have a certain reducing property, and under the joint action of the reducing active species (main) and alcohol radicals (secondary) of the irradiation system, the metal salt is reduced to metal atoms. And because metal atoms tend to aggregate during the formation process, the nitrogen sites in the graphite phase carbon nitride used in the present invention can capture metal atoms and reduce them to metal single atoms in situ, thereby reducing the aggregation tendency of metal atoms and promoting the formation of metal atom catalysts.

[0033] In specific implementation, this step is performed after the air in the centrifuge tube is exhausted. The specific operation may be to introduce nitrogen into the centrifuge tube for 15-30 seconds to exhaust the air in the centrifuge tube. This step does not require an inert atmosphere environment for irradiation. The radiation source for irradiation treatment may be selected from an electron accelerator, 60 Co or 137Cs; and because the irradiated object exists in a liquid environment, the irradiation dose rate of the selected irradiation treatment is 0.4~1.0 kGy / h, the irradiation time is 6~25 h, and the total irradiation dose is greatly reduced to 2.4-25 kGy. As a preferred example, the irradiation dose rate can be controlled at 0.5~0.8 kGy / h, and the irradiation time is 8~10 h.

[0034] S3, filtering the mixed system after irradiation, washing the obtained solid, and vacuum drying it to finally obtain the metal atom catalyst; This step is used to separate and purify the metal atom catalyst generated in the irradiation system. The separation treatment method is suction filtration to remove the isopropanol solution in the irradiation system. The obtained solid is washed and vacuum dried to finally obtain the metal atom catalyst. The washing operation specifically includes: washing the obtained solid with deionized water for 1-5 times.

[0035] In a second aspect, the present invention provides a metal atom catalyst obtained by the method for in-situ synthesis of metal atom catalysts based on ionizing radiation as described in the first aspect.

[0036] In order to enable those skilled in the art to more clearly understand the present invention, the metal atom catalyst based on in-situ synthesis by ionizing radiation and the synthesis method described in the present invention are now described in detail through the following examples.

[0037] It should be noted that the isopropanol reagent used in the embodiments of the present invention is a commercially available product with a purity of 99.9%.

[0038] Example 1 100 mg of graphite carbon nitride and 80.6 mg of CoCl2.6H2O (the mass of cobalt ions is about 19.96 mg) were added to 50 ml of ethanol solution (in a glass bottle with a lid) and kept at a constant temperature of 60 o C for 2 hours and then dried under vacuum (60 o C). The solid was then transferred to a 15 ml centrifuge tube, 1.7 μL of isopropanol and deionized water (isopropanol concentration was 0.1 M) were added, and the tube was capped. The dose rate was 0.6 kGy / h, and after 8 hours of irradiation, the tube was left to stand for 1 hour and then vacuum filtered. The collected solid was washed with deionized water (100 ml of deionized water was stirred for 1 hour), then filtered and vacuum dried (60 o C) The carbon nitride-supported cobalt metal atom catalyst is obtained.

[0039] Figure 2 The spherical aberration electron microscope image of the metal atom catalyst provided in Example 1 of the present invention is shown, wherein the left image shows the overall image of the material, and the right image shows the distribution of cobalt metal atoms in the material, such as Figure 2As shown, cobalt metal atoms are evenly distributed in the metal atom catalyst and are relatively large in number. According to ICP-MS analysis, the loading rate of single-atom cobalt in the metal atom catalyst prepared in Example 1 reaches 17.4%.

[0040] Example 2 100 mg of graphite carbon nitride and 20 mg of CuCl2 (the mass of copper ions is about 9.44 mg) were added to 50 ml of ethanol solution (in a glass bottle with a lid) and kept at a constant temperature of 60 o C for 2 hours and then dried under vacuum (60 o C). The solid was then transferred to a 15 ml centrifuge tube, 1.7 μL of isopropanol and deionized water (isopropanol concentration was 0.1 M) were added, and the tube was capped. The dose rate was 0.6 kGy / h, and after 8 hours of irradiation, the tube was left to stand for 1 hour and then vacuum filtered. The collected solid was washed with deionized water (100 ml of deionized water was stirred for 1 hour), then filtered and vacuum dried (60 o C) The carbon nitride-supported copper metal atom catalyst is obtained.

[0041] Figure 3 The spherical aberration electron microscope image of the metal atom catalyst provided in Example 2 of the present invention is shown, as Figure 3 As shown, copper metal atoms are evenly distributed in the metal atom catalyst and are relatively large in number.

[0042] Example 3 100 mg of graphite carbon nitride, 41.9 mg of FeCl3.6H2O (the mass of iron ions is about 8.43 mg), and 20 mg of CuCl2 (the mass of copper ions is about 9.44 mg) were added to 50 ml of ethanol solution (with a lid on the glass bottle) and kept at a constant temperature of 60 o C for 2 hours and then dried under vacuum (60 o C). Then the solid was transferred to a 15 ml centrifuge tube, 1.7 μL of isopropanol and deionized water (isopropanol concentration was 0.1 M) were added, and the tube was capped. The dose rate was 0.6 kGy / h, and after 8 h of irradiation, the tube was left standing for 1 h and then vacuum filtered. The collected solid was washed with deionized water (100 ml of deionized water was stirred for 1 h), then filtered and vacuum dried (60 o C) The carbon nitride-supported copper and iron bimetallic atom catalyst is obtained.

[0043] Figure 4 The spherical aberration electron microscope image of the metal atom catalyst provided in Example 3 of the present invention is shown. Figure 4 As shown, the copper and iron metal atoms are evenly distributed in the metal atom catalyst and the number is large.

[0044] Example 4 100 mg of graphite carbon nitride, 40.3 mg of CoCl2.6H2O (the mass of cobalt ions is about 10.01 mg), 41.9 mg of FeCl3.6H2O (the mass of iron ions is about 8.43 mg), and 20 mg of CuCl2 (the mass of copper ions is about 9.44 mg) are added to 50 ml of ethanol solution (with a lid on the glass bottle) and kept at a constant temperature of 60 o C for 2 h and then dried under vacuum (60 o C). Then the obtained solid was transferred to a 15 ml centrifuge tube, 1.7 μL of isopropanol and deionized water (isopropanol concentration is 0.1M) were added, and the lid was closed. The dose rate was 0.6 kGy / h, and after 8 h of irradiation, the tube was left standing for 1 h and then vacuum filtered. The collected solid was washed with deionized water (stirring with 100 ml of deionized water for 1 h), then filtered and vacuum dried to obtain the carbon nitride-supported iron, cobalt and copper trimetallic atom catalyst.

[0045] Figure 5 The spherical aberration electron microscope image of the metal atom catalyst provided in Example 4 of the present invention is shown. Figure 5 As shown, the three metal atoms of iron, cobalt and copper are evenly distributed in the metal atom catalyst and in large quantities.

[0046] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine the different embodiments or examples described in this specification.

[0047] For the method embodiments, for the sake of simplicity, they are all described as a series of action combinations, but those skilled in the art should know that the present invention is not limited by the order of the actions described, because according to the present invention, some steps can be performed in other orders or simultaneously. Secondly, those skilled in the art should also know that the embodiments described in the specification are all preferred embodiments, and the actions and components involved are not necessarily required by the present invention.

[0048] The above is a detailed introduction to a metal atom catalyst and a synthesis method based on in-situ synthesis by ionizing radiation provided by the present invention. Specific examples are used herein to illustrate the principles and implementation methods of the present invention. The description of the above embodiments is only used to help understand the method of the present invention and its core idea. At the same time, for a person skilled in the art, according to the idea of ​​the present invention, there will be changes in the specific implementation methods and application scopes. In summary, the content of this specification should not be understood as a limitation on the present invention.

Claims

1. A method for in-situ synthesis of metal atom catalysts based on ionizing radiation, characterized in that: The method comprises the following steps: S1. Add the catalyst support and the metal salt to an ethanol solution, stir at 50°C to 70°C for 1 to 4 hours, and then filter out the solid, wherein the mass ratio of the catalyst support to the metal ion in the metal salt is 100:9-30; S2, vacuum drying the solid, then mixing it with an appropriate amount of isopropanol and deionized water in a centrifuge tube, exhausting the air in the centrifuge tube, and then irradiating it, with an irradiation dose rate of 0.4-1.0 kGy / h and an irradiation time of 6-25h; S3, filtering the mixed system after irradiation, washing the obtained solid, and vacuum drying it to finally obtain the metal atom catalyst; The catalyst carrier is a nitrogen-doped carbon material; The metal salt comprises soluble salts containing iron, cobalt, nickel, manganese or copper, or at least two of the soluble salts containing iron, cobalt, nickel, manganese and copper are mixed in any proportion.

2. The method for in-situ synthesis of metal atom catalysts based on ionizing radiation according to claim 1, characterized in that: The mass volume ratio of the catalyst carrier to the ethanol solution is 100 mg: 50-70 mL; The mass volume ratio of the catalyst carrier to the isopropanol is 100 mg:1.5-2.0 μL.

3. The method for in-situ synthesis of metal atom catalysts based on ionizing radiation according to claim 1, characterized in that: The vacuum drying process is carried out at a temperature of 40 to 60°C and for a time of 6 to 12 hours.

4. The method for in-situ synthesis of metal atom catalysts based on ionizing radiation according to claim 1, characterized in that: The radiation source of the irradiation treatment is an electron accelerator, 60 Co or 137 Cs.

5. The method for in-situ synthesis of metal atom catalysts based on ionizing radiation according to claim 1, characterized in that: The temperature controlled by the constant temperature stirring is 60°C.

6. The method for in-situ synthesis of metal atom catalysts based on ionizing radiation according to claim 1, characterized in that: The washing comprises: washing the obtained solid with deionized water for 1-5 times.

7. The method for in-situ synthesis of metal atom catalysts based on ionizing radiation according to claim 1, characterized in that: The catalyst carrier is graphite-phase carbon nitride, and the metal salt is at least one of CuCl2, FeCl3•6H2O and CoCl2•6H2O.

8. The method for in-situ synthesis of metal atom catalysts based on ionizing radiation according to claim 1, characterized in that: The irradiation dose rate is 0.5-18 kGy / h, and the irradiation time is 8-10 h.

9. The method for in-situ synthesis of metal atom catalysts based on ionizing radiation according to claim 1, characterized in that: The exhausting of the air in the centrifuge tube comprises: introducing nitrogen into the centrifuge tube for 15-30 seconds to exhaust the air in the centrifuge tube.

10. A metal atom catalyst obtained by the method for in-situ synthesis of metal atom catalysts based on ionizing radiation as claimed in any one of claims 1 to 9.

Images