A single-atom and multi-atom transition metal co-doped carbon catalytic material, its preparation method and application

Abstract

This invention belongs to the field of catalysis technology, specifically relating to a carbon catalytic material co-doped with single-atom and multi-atom transition metals, its preparation method, and its application. The invention involves plasma calcining activated carbon material with a transition metal salt to obtain a carbon material loaded with multi-atom transition metal nanoparticles. Then, through acid etching, some of the multi-atom transition metal nanoparticles are dispersed into single-atom transition metals, thus obtaining a carbon catalytic material simultaneously loaded with single-atom and multi-atom transition metal nanoparticles. Compared to single-atom transition metals, multi-atom transition metal nanoparticles exhibit stronger bonding and stability with the carbon material, and are less prone to aggregation during catalysis, thereby improving the stability of the carbon catalytic material. Furthermore, activation, plasma calcination, and acid etching increase the porous structure of the carbon material surface, increasing its specific surface area, which is beneficial for increasing active sites and thus improving catalytic activity.

Description

Technical Field

[0001] This invention belongs to the field of catalysis technology, specifically relating to a single-atom and multi-atom transition metal co-doped carbon catalytic material, its preparation method, and its application. Background Technology

[0002] Transition metal (such as Fe, Co, Ni, Mn, and Cu) and nitrogen-doped porous carbon catalysts (referred to as MNCs) represent an emerging family of materials with atomically dispersed metal species. Transition metals have recently attracted significant attention due to their abundant reserves, low toxicity, excellent activity, and stability. MNC catalysts are currently widely used in energy storage and conversion, biomedicine, organic conversion, and catalytic reactions involving tranexamic acid, generally exhibiting superior catalytic performance.

[0003] High-temperature pyrolysis under an inert atmosphere of nitrogen-containing organic ligand-metal complexes and / or carbon supports, or metal-organic frameworks, or mixtures of metal salts and renewable biomass is the most common method for preparing metal-organic catalysts (MNCs). However, a key challenge of this synthetic method lies in the highly structurally heterogeneous coexistence of complex metal sites, including atomically dispersed metal species (M-Nx) and metal-containing metal nanoparticles (NPs) and / or nanoclusters (NCs), making it difficult to distinguish the properties of catalytically active sites. Removing insoluble metal-containing NPs and / or NCs requires specific post-treatment processes, such as acid chemical etching or treatment with concentrated H₂O₂ and high-temperature Cl₂ after thermal decomposition, ultimately forming atomically dispersed M-Nx species, which are widely accepted as catalytically active sites. Although atomically dispersed M-Nx catalysts exhibit high catalytic activity, they are also less stable and prone to aggregation during catalysis, thus reducing their catalytic activity. Summary of the Invention

[0004] In view of this, the purpose of this invention is to provide a single-atom and multi-atom transition metal co-doped carbon catalytic material, its preparation method and application. The single-atom and multi-atom transition metal co-doped carbon catalytic material prepared by this invention has excellent catalytic activity and stability.

[0005] To achieve the above objectives, the present invention provides the following technical solution:

[0006] This invention provides a method for preparing single-atom and multi-atom transition metal co-doped carbon catalytic materials, characterized by comprising the following steps:

[0007] Provides biomass carbon;

[0008] The biomass carbon is mixed with an alkaline solution and then activated to obtain activated carbon material.

[0009] The activated carbon material and transition metal salt are mixed and subjected to plasma calcination to obtain a calcination product, which includes a carbon support and multi-atom transition metal nanoparticles loaded on the surface of the carbon support.

[0010] The calcined product is mixed with an acidic solution and subjected to acid etching to obtain single-atom and multi-atom transition metal co-doped carbon catalytic materials.

[0011] Preferably, the alkaline solution includes sodium hydroxide solution and / or potassium hydroxide solution; the concentration of the alkaline solution is 4 to 20 mmol / L.

[0012] Preferably, the transition metal salt includes one or more of iron salts, nickel salts, and cobalt salts.

[0013] Preferably, the plasma calcination has a power of 100-2000W, a temperature of 400-800℃, a vacuum degree of 100-1000Pa, and a holding time of 0.1-0.6h.

[0014] Preferably, the acidic solution includes one or more of sulfuric acid, nitric acid, and hydrochloric acid.

[0015] Preferably, the concentration of the acidic solution is 1–10 mmol / L; the temperature of the acid etching treatment is 30–100°C, and the time is 2–20 h.

[0016] Preferably, the method for preparing biomass carbon is to calcine the biomass; the biomass is one or more of shrimp shells, rice stalks, bamboo leaves, reeds, and watermelon rinds.

[0017] Preferably, the calcination temperature is 700–1200°C, and the holding time is 3–20 h.

[0018] The present invention also provides a single-atom and multi-atom transition metal co-doped carbon catalytic material prepared by the preparation method described above, comprising a porous carbon material and single-atom and multi-atom transition metal nanoparticles doped on the porous carbon material.

[0019] This invention also provides the application of the single-atom and multi-atom transition metal co-doped carbon catalytic materials described above in the preparation of carbon-carbon double-bond compounds by hydrogenation of carbon-carbon triple bonds.

[0020] This invention provides a method for preparing a carbon catalytic material co-doped with single-atom and multi-atom transition metals, comprising the following steps: providing biomass carbon; mixing the biomass carbon with an alkaline solution and performing activation treatment to obtain activated carbon material; mixing the activated carbon material with a transition metal salt and performing plasma calcination to obtain a calcined product, wherein the calcined product includes a carbon support and transition metal nanoparticles loaded on the surface of the carbon support; mixing the calcined product with an acidic solution and performing acid etching treatment to obtain a carbon catalytic material co-doped with single-atom and multi-atom transition metals. This invention obtains a carbon material loaded with multi-atom transition metal nanoparticles by plasma calcination of the activated carbon material with a transition metal salt, and then dispersing some of the multi-atom transition metal nanoparticles into single-atom transition metals through acid etching, thereby obtaining a carbon catalytic material simultaneously loaded with single-atom and multi-atom transition metal nanoparticles. Compared to single-atom transition metals, multi-atom transition metal nanoparticles have stronger binding force and stability with carbon materials, and are less prone to aggregation during catalysis, thus improving the stability of the carbon catalytic material. Furthermore, activation treatment, plasma calcination, and acid etching can increase the porous structure of the carbon material surface and improve its specific surface area, which is beneficial for increasing active sites and thus enhancing catalytic activity. Therefore, the preparation method provided by this invention can prepare single-atom and multi-atom transition metal co-doped carbon catalytic materials with excellent catalytic activity and stability.

[0021] Furthermore, this invention utilizes biomass as a raw material to prepare carbon materials, which are widely available and inexpensive. Attached Figure Description

[0022] Figure 1 This is a TEM image of the single-atom and multi-atom transition metal co-doped carbon catalytic material prepared in Example 1 of the present invention. Detailed Implementation

[0023] This invention provides a method for preparing single-atom and multi-atom transition metal co-doped carbon catalytic materials, comprising the following steps:

[0024] Provides biomass carbon;

[0025] The biomass carbon is mixed with an alkaline solution and then activated to obtain activated carbon material.

[0026] The activated carbon material and transition metal salt are mixed and subjected to plasma calcination to obtain a calcination product, which includes a carbon support and multi-atom transition metal nanoparticles loaded on the surface of the carbon support.

[0027] The calcined product is mixed with an acidic solution and subjected to acid etching to obtain single-atom and multi-atom transition metal co-doped carbon catalytic materials.

[0028] Unless otherwise specified, the present invention does not have special requirements on the source of the raw materials used in the preparation, and commercially available products well known to those skilled in the art can be used.

[0029] This invention provides biomass carbon.

[0030] In this invention, the preferred method for preparing biomass carbon is to calcine the biomass.

[0031] In this invention, the biomass is preferably one or more of shrimp shells, rice stalks, bamboo leaves, reeds, and watermelon rinds, more preferably watermelon rinds; when the biomass is one of the above-mentioned types, this invention does not have a special limitation on the ratio of different types of biomass, and any ratio is acceptable; the calcination temperature is preferably 700-1200℃, more preferably 800-1000℃; the heat preservation time is preferably 3-20h, more preferably 8-10h.

[0032] This invention obtains biomass carbon by calcining biomass at high temperatures.

[0033] After obtaining biomass carbon, the present invention mixes the biomass carbon with an alkaline solution and performs an activation treatment to obtain activated carbon material.

[0034] In this invention, the alkaline solution preferably includes sodium hydroxide solution and / or potassium hydroxide solution, more preferably potassium hydroxide solution; when the alkaline solution is one of the above-mentioned types, this invention does not have a special limitation on the ratio of different types of alkaline solutions, and any ratio is acceptable; the concentration of the alkaline solution is preferably 4-20 mol / L, more preferably 7-9 mol / L; the activation treatment time is preferably 16-36 h, more preferably 22-26 h.

[0035] In this invention, the activation process preferably involves immersing the carbon material in an alkaline solution and stirring. This invention does not impose any particular limitation on the stirring process; it can be selected according to actual needs.

[0036] This invention activates biomass carbon materials, which on the one hand cleans uncarbonized materials, and on the other hand, activation can create pores on the surface of carbon materials, increasing the specific surface area and surface functional groups of carbon materials.

[0037] After the activation treatment, the present invention preferably filters and dries the resulting mixture sequentially to obtain activated carbon material. The present invention does not have specific limitations on the filtration process; it can be selected according to actual needs. In the present invention, the drying temperature is preferably 100°C, and the drying time is preferably 8 hours.

[0038] After obtaining the activated carbon material, the present invention mixes the activated carbon material with a transition metal salt and performs plasma calcination to obtain a calcination product, wherein the calcination product includes a carbon support and transition metal nanoparticles formed by multiple atoms loaded on the surface of the carbon support.

[0039] In this invention, the transition metal salt preferably includes one or more of iron salt, nickel salt and cobalt salt, more preferably nickel salt, and most preferably nickel nitrate; when the transition metal salt is one of the above-mentioned types, this invention does not have a special limitation on the ratio of different types of metal salts, and any ratio is acceptable; the mass ratio of the activated carbon material to the transition metal salt is preferably (3-8):1, more preferably (4.2-5):1.

[0040] In this invention, the preferred method for mixing the activated carbon material and the transition metal salt is to mix the activated carbon material and the aqueous solution of the transition metal salt under stirring conditions; the preferred stirring time is 6 hours; this invention does not have a specific limitation on the stirring power, which can be selected according to actual needs.

[0041] In this invention, the mixture obtained by mixing the activated carbon material and the transition metal salt is preferably dried before plasma calcination; the drying temperature is preferably 80°C and the drying time is preferably 8 hours.

[0042] In this invention, the power of the plasma calcination is preferably 100-2000W, more preferably 200-1000W; the temperature is preferably 400-800℃, more preferably 500-700℃; the vacuum degree is preferably 100-1000Pa, more preferably 200-500Pa; and the holding time is preferably 0.1-0.6h, more preferably 0.1-0.3h.

[0043] This invention utilizes plasma calcination of a mixture of activated carbon materials and transition metal salts. On one hand, it reduces the active metal ions in the transition metal salts to obtain transition metal atoms at high temperatures. On the other hand, it etches the carbon materials to obtain more porous structures, thereby increasing the specific surface area of ​​the carbon materials, increasing the number of active metal sites, and improving catalytic activity. Plasma calcination can also reduce carbonization time and increase the porous structure of the carbon materials.

[0044] After obtaining the calcined product, the present invention mixes the calcined product with an acidic solution and performs acid etching treatment to obtain a single-atom and multi-atom transition metal co-doped carbon catalyst material.

[0045] In this invention, the acidic solution preferably includes one or more of sulfuric acid, nitric acid, and hydrochloric acid, more preferably sulfuric acid; when the acidic solution is one of the above-mentioned types, this invention does not have a special limitation on the ratio of different types of acidic solutions, and any ratio is acceptable; the concentration of the acidic solution is preferably 1-10 mol / L, more preferably 1-5 mol / L; the temperature of the acid etching treatment is preferably 30-100℃, more preferably 70-90℃, and the time is preferably 2-20 h, more preferably 10-15 h.

[0046] In this invention, the acid etching process is preferably performed by immersing the calcined product in an acidic solution.

[0047] Under high-temperature calcination, ionic metals polymerize to form multi-atom nanoparticles. In this invention, the transition metal nanoparticles formed by multi-atom nanoparticles loaded on a carbon support by acid etching are partially dispersed into single-atom metals, increasing the active sites and thus improving catalytic activity.

[0048] The present invention also provides a single-atom and multi-atom transition metal co-doped carbon catalytic material prepared by the preparation method described above, comprising a porous carbon material and single-atom and multi-atom transition metal nanoparticles doped on the porous carbon material.

[0049] In this invention, the mass of the transition metal nanoparticles formed by the single-atom and multi-atom transition metals is preferably 2 to 5% of the mass of the single-atom and multi-atom transition metal co-doped carbon catalytic material, more preferably 2 to 3%.

[0050] This invention also provides the application of the single-atom and multi-atom transition metal co-doped carbon catalytic materials described above in the preparation of carbon-carbon double-bond compounds by hydrogenation of carbon-carbon triple bonds.

[0051] In this invention, the preferred application is the hydrogenation of phenylacetylene to styrene. In an embodiment of this invention, the specific process of the hydrogenation of phenylacetylene to styrene involves loading the single-atom and multi-atom transition metal co-doped carbon catalyst into a high-pressure reactor, using ethanol as a solution, and reacting for 1 hour at a temperature of 60°C, a hydrogen reaction pressure of 0.2 MPa, and a mass ratio of phenylacetylene to the single-atom and multi-atom transition metal co-doped carbon catalyst of 20:1.

[0052] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention, but they should not be construed as limiting the scope of protection of the present invention.

[0053] Example 1

[0054] Watermelon rind was dried, ground into powder, and calcined at 1000℃ for 9 hours to obtain carbon material. The carbon material was added to an 8 mol / L potassium hydroxide solution and stirred for 24 hours. After filtration, it was dried at 100℃ for 8 hours to obtain activated carbon material. 1 g of the activated carbon material was weighed and mixed with 265 mg of nickel nitrate hexahydrate for 6 hours. After drying at 80℃ for 8 hours, it was calcined under plasma conditions of 300 W power, 700℃ temperature, and 300 Pa vacuum for 0.2 hours. The calcined product was then etched in 2 mol / L sulfuric acid at 80℃ for 12 hours to obtain single-atom and multi-atom transition metal co-doped carbon catalyst material.

[0055] Example 2

[0056] Watermelon rind was dried, ground into powder, and calcined at 800℃ for 9 hours to obtain carbon material. The carbon material was added to an 8 mol / L potassium hydroxide solution and stirred for 24 hours. After filtration, it was dried at 100℃ for 8 hours to obtain activated carbon material. 1 g of the activated carbon material was weighed and mixed with 265 mg of nickel nitrate hexahydrate for 6 hours. After stirring, it was dried at 80℃ for 8 hours and then calcined under plasma conditions of 300 W power, 700℃ temperature, and 300 Pa vacuum for 0.2 hours. The calcined product was then etched in 2 mol / L sulfuric acid at 80℃ for 12 hours to obtain single-atom and multi-atom transition metal co-doped carbon catalyst material.

[0057] Example 3

[0058] Watermelon rind was dried, ground into powder, and calcined at 1000℃ for 9 hours to obtain carbon material. The carbon material was added to a 4 mol / L potassium hydroxide solution and stirred for 24 hours. After filtration, it was dried at 100℃ for 8 hours to obtain activated carbon material. 1 g of the activated carbon material was weighed and mixed with 265 mg of nickel nitrate hexahydrate for 6 hours. After stirring, it was dried at 80℃ for 8 hours and then calcined under plasma conditions of 300 W power, 700℃ temperature, and 300 Pa vacuum for 0.2 hours. The calcined product was then etched in 2 mol / L sulfuric acid at 80℃ for 12 hours to obtain single-atom and multi-atom transition metal co-doped carbon catalyst material.

[0059] Example 4

[0060] Watermelon rind was dried, ground into powder, and calcined at 1000℃ for 9 hours to obtain carbon material. The carbon material was added to an 8 mol / L potassium hydroxide solution and stirred for 24 hours. After filtration, it was dried at 100℃ for 8 hours to obtain activated carbon material. 1 g of the activated carbon material was weighed and mixed with 265 mg of nickel nitrate hexahydrate for 6 hours. After stirring, it was dried at 80℃ for 8 hours and then calcined under plasma conditions of 300 W power, 400℃ temperature, and 300 Pa vacuum for 0.2 hours. The calcined product was then etched in 2 mol / L sulfuric acid at 80℃ for 12 hours to obtain single-atom and multi-atom transition metal co-doped carbon catalyst material.

[0061] Example 5

[0062] Watermelon rind was dried, ground into powder, and calcined at 1000℃ for 9 hours to obtain carbon material. The carbon material was added to an 8 mol / L potassium hydroxide solution and stirred for 24 hours. After filtration, it was dried at 100℃ for 8 hours to obtain activated carbon material. 1 g of the activated carbon material was weighed and mixed with 265 mg of nickel nitrate hexahydrate for 6 hours. After stirring, it was dried at 80℃ for 8 hours and then calcined under plasma conditions of 300 W power, 700℃ temperature, and 300 Pa vacuum for 0.2 hours. The calcined product was then etched in 6 mol / L sulfuric acid at 80℃ for 12 hours to obtain single-atom and multi-atom transition metal co-doped carbon catalyst material.

[0063] Example 6

[0064] Watermelon rind was dried, ground into powder, and calcined at 1000℃ for 9 hours to obtain carbon material. The carbon material was added to an 8 mol / L potassium hydroxide solution and stirred for 24 hours. After filtration, it was dried at 100℃ for 8 hours to obtain activated carbon material. 1 g of the activated carbon material was weighed and mixed with 265 mg of nickel nitrate hexahydrate for 6 hours. After stirring, it was dried at 80℃ for 8 hours and then calcined under plasma conditions of 300 W power, 700℃ temperature, and 300 Pa vacuum for 0.2 hours. The calcined product was then etched in 0.5 mol / L sulfuric acid at 80℃ for 12 hours to obtain single-atom and multi-atom transition metal co-doped carbon catalyst material.

[0065] Example 7

[0066] Watermelon rind was dried, ground into powder, and calcined at 1000℃ for 9 hours to obtain carbon material. The carbon material was added to an 8 mol / L potassium hydroxide solution and stirred for 24 hours. After filtration, it was dried at 100℃ for 8 hours to obtain activated carbon material. 1 g of the activated carbon material was weighed and mixed with 215 mg of nickel nitrate hexahydrate for 6 hours. After drying at 80℃ for 8 hours, it was calcined under plasma conditions of 300 W power, 700℃ temperature, and 300 Pa vacuum for 0.2 hours. The calcined product was then etched in 2 mol / L sulfuric acid at 80℃ for 12 hours to obtain single-atom and multi-atom transition metal co-doped carbon catalyst material.

[0067] Comparative Example 1

[0068] Watermelon rind was dried, ground into powder, and calcined at 1000℃ for 9 hours to obtain carbon material. The carbon material was added to an 8 mol / L potassium hydroxide solution and stirred for 24 hours. After filtration, it was dried at 100℃ for 8 hours to obtain activated carbon material. 1 g of the activated carbon material was weighed and mixed with 265 mg of nickel nitrate hexahydrate for 6 hours. After drying at 80℃ for 8 hours, it was calcined under plasma conditions of 300 W power, 700℃ temperature, and 300 Pa vacuum for 0.2 hours to obtain metal-doped carbon catalyst material.

[0069] Application Examples 1-7

[0070] The single-atom and multi-atom transition metal co-doped carbon catalysts obtained in Examples 1-7 were respectively loaded into a high-pressure reactor. Using ethanol as a solution, the reaction was carried out at a temperature of 60°C, a reaction pressure of 0.2 MPa hydrogen, and a mass ratio of phenylacetylene to single-atom and multi-atom transition metal co-doped carbon catalysts of 20:1 for 1 hour. The hydrogenation of phenylacetylene yielded styrene.

[0071] Comparative Application Example 1

[0072] The metal-doped carbon catalyst obtained in Comparative Example 1 was loaded into a high-pressure reactor. Using ethanol as a solution, the reaction was carried out at a temperature of 60°C, a hydrogen reaction pressure of 0.2 MPa, and a mass ratio of phenylacetylene to single-atom and multi-atom transition metal co-doped carbon catalyst of 20:1 for 1 hour. The hydrogenation of phenylacetylene yielded styrene.

[0073] Performance testing

[0074] (1) The specific surface area of ​​the single-atom and multi-atom transition metal co-doped carbon catalytic materials obtained in Examples 1 to 7 was tested, and the results are shown in Table 1.

[0075] Table 1. Specific surface areas of the single-atom and multi-atom transition metal co-doped carbon catalytic materials obtained in Examples 1-7 and the metal-doped carbon catalytic material obtained in Comparative Example 1.

[0076] sample <![CDATA[Specific surface area m 2 / g]]> Comparative Example 1 683.1 Example 1 983.5 Example 2 734.3 Example 3 722.6 Example 4 892.6 Example 5 912.1 Example 6 938.4 Example 7 975.2

[0077] As shown in Table 1, the specific surface area of ​​the single-atom and multi-atom transition metal co-doped carbon catalyst prepared by this invention can reach 983.5 m². 2 / g, which is much higher than the specific surface area of ​​the metal-doped carbon catalyst in Comparative Example 1 (683.1m²). 2 The figure (g) indicates that the single-atom and multi-atom transition metal co-doped carbon catalytic materials prepared by this invention have a high specific surface area, which is beneficial to increasing active sites and thus improving catalytic activity.

[0078] (2) The conversion rate and selectivity of styrene produced by hydrogenation of phenylacetylene in corresponding use cases 1 to 7 and comparative application example 1 were tested, and the results are shown in Table 2.

[0079] Table 2 shows the conversion rates and selectivity of phenylacetylene hydrogenation to styrene in Application Examples 1-7 and Comparative Application Example 1.

[0080] sample Conversion rate / % Selectivity / % Comparative Application Example 1 55.2 85.3 Application Example 1 97.6 95.2 Application Example 2 85.6 91.3 Application Example 3 78.3 90.3 Application Example 4 74.6 88.5 Application Example 5 88.9 93.6 Application Example 6 80.1 86.3 Application Example 7 70.1 94.2

[0081] As shown in Table 2, the single-atom and multi-atom transition metal co-doped carbon catalytic material prepared in this invention achieves a conversion rate of 97.6% and a selectivity of 95.2% in the hydrogenation of phenylacetylene to styrene. This indicates that the single-atom and multi-atom transition metal co-doped carbon catalytic material prepared in this invention has excellent catalytic efficiency and selectivity.

[0082] (3) The catalytic stability of the single-atom and multi-atom transition metal co-doped carbon catalytic materials and the metal-doped carbon catalytic materials obtained in Example 1 is shown in Table 3.

[0083] Table 3. Catalytic stability of single-atom and multi-atom transition metal co-doped carbon catalytic materials and metal-doped carbon catalytic materials obtained in Example 1.

[0084]

[0085] As shown in Table 3, the single-atom and multi-atom transition metal co-doped carbon catalytic materials prepared in this invention still exhibit excellent conversion rate and selectivity after eight repeated catalytic cycles, indicating that the single-atom and multi-atom transition metal co-doped carbon catalytic materials prepared in this invention have excellent catalytic stability.

[0086] (4) The single-atom and multi-atom transition metal co-doped carbon catalytic materials prepared in Example 1 were tested using transmission electron microscopy, and the results are as follows: Figure 1 As shown.

[0087] from Figure 1It can be seen that the single-atom and multi-atom transition metal co-doped carbon catalytic materials prepared in this invention contain various sizes of metal particles, including single-atom-level metal particles and nanoparticle clusters.

[0088] Although the above embodiments have provided a detailed description of the present invention, they are only some embodiments of the present invention and not all embodiments. People can obtain other embodiments based on these embodiments without creative effort, and these embodiments all fall within the protection scope of the present invention.

Claims

1. A method for preparing a single-atom and multi-atom transition metal co-doped carbon catalytic material, characterized in that, Includes the following steps: Provides biomass carbon; The biomass carbon is mixed with an alkaline solution and then activated to obtain activated carbon material. The activated carbon material and transition metal salt are mixed and subjected to plasma calcination to obtain a calcination product, which includes a carbon support and multi-atom transition metal nanoparticles loaded on the surface of the carbon support. The calcined product is mixed with an acidic solution and subjected to acid etching to obtain a single-atom and multi-atom transition metal co-doped carbon catalytic material. The plasma calcination has a power of 100~2000W, a temperature of 400~800℃, a vacuum degree of 100~1000Pa, and a holding time of 0.1~0.6h.

2. The preparation method according to claim 1, characterized in that, The alkaline solution includes sodium hydroxide solution and / or potassium hydroxide solution; the concentration of the alkaline solution is 4~20 mmol / L.

3. The preparation method according to claim 1, characterized in that, The transition metal salts include one or more of iron salts, nickel salts, and cobalt salts.

4. The preparation method according to claim 1, characterized in that, The acidic solution includes one or more of sulfuric acid, nitric acid, and hydrochloric acid.

5. The preparation method according to claim 1 or 4, characterized in that, The concentration of the acidic solution is 1~10 mmol / L; the temperature of the acid etching treatment is 30~100℃, and the time is 2~20h.

6. The preparation method according to claim 1, characterized in that, The method for preparing biomass carbon involves calcining the biomass; the biomass is one or more of the following: shrimp shells, rice stalks, bamboo leaves, reeds, and watermelon rinds.

7. The preparation method according to claim 6, characterized in that, The calcination temperature is 700~1200℃, and the holding time is 3~20h.

8. The single-atom and multi-atom transition metal co-doped carbon catalytic material prepared by the preparation method according to any one of claims 1 to 7, characterized in that, It includes porous carbon materials and single-atom transition metals and multi-atom transition metal nanoparticles doped on the porous carbon materials.

9. The application of the single-atom and multi-atom transition metal co-doped carbon catalyst material according to claim 8 in the preparation of carbon-carbon double-bond compounds by hydrogenation of carbon-carbon triple bonds.

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