A method for preparing a carbon-based monatomic material based on a melting method, a carbon-based monatomic material and applications thereof

Abstract

This invention belongs to the field of materials technology, specifically relating to a method for preparing carbon-based single-atom materials based on a melt method, the carbon-based single-atom materials, and their applications. The method includes the following steps: preparing a saturated solution of a template salt and water, ensuring the template salt is completely dissolved, then adding ethanol, stirring until the template salt is fully precipitated, filtering, washing with ethanol, and drying by forced air to obtain a template agent; mixing the template agent, a nitrogen-containing compound, an organic carbon compound, and a water-soluble metal salt together to obtain a precursor; placing the precursor in a reactor and heat-treating it under a protective atmosphere to obtain a heat-treated product; dispersing the heat-treated product in water, filtering, and drying to obtain the carbon-based single-atom material. This invention can reduce costs, as the raw materials used in the synthesis process are inexpensive and readily available, the synthesis process is simple, the operation is convenient, and the raw materials can be scaled up proportionally, thus enabling large-scale, mass production.

Description

Technical Field

[0001] This invention belongs to the field of materials technology, specifically relating to a method for preparing carbon-based single-atom materials based on a melting method, carbon-based single-atom materials and their applications. Background Technology

[0002] Carbon-based single-atom materials: The main matrix component is carbon. Other easily coordinated elements (such as nitrogen) are used to anchor individual metal atoms onto the carbon substrate. The resulting material forms an MN structure with nitrogen atoms and metal single atoms. X Site structure, where X is 3 or 4.

[0003] Currently, carbon-based single-atom materials are widely used in electrocatalysis, photocatalysis, thermocatalysis, and organic synthesis. However, most reported carbon-based single-atom materials primarily use graphene or organometallic frameworks (MOFs) as substrates. These substrates are extremely expensive, posing a significant challenge to the large-scale, mass production and application of carbon-based single-atom materials. Furthermore, while pyrolyzed carbon is an inexpensive carbon source, it is bulk carbon with a small specific surface area and few effective single-atom sites, making it difficult to use for carbon-based single-atom materials. The morphologies of existing GO-based single-atom materials and carbon-based single-atom materials prepared using pyrolyzed bulk carbon are as follows: Figure 1 As shown above, carbon-based single-atom materials are progressing towards low-cost and high-efficiency synthesis.

[0004] There is no simple and low-cost preparation method for shell-shaped and sheet-shaped carbon-based single-atom materials in the existing technology. Therefore, there is an urgent need to provide a simple and low-cost method for preparing carbon-based single-atom materials. Summary of the Invention

[0005] The purpose of this invention is to provide a method for preparing carbon-based single-atom materials based on a melting method, carbon-based single-atom materials and their applications. The process is simple and low-cost, and it can realize the large-scale preparation of shell-shaped and sheet-shaped carbon-based single-atom materials.

[0006] The objective of this invention is achieved through the following technical solution:

[0007] This invention provides a method for preparing carbon-based single-atom materials based on a melt method, comprising the following steps:

[0008] (1) The template agent, nitrogen-containing compound, organic carbon compound and water-soluble metal salt are mixed together to obtain the precursor;

[0009] (2) The precursor is placed in a reactor and heat-treated under a protective atmosphere to obtain the heat-treated product.

[0010] (3) Disperse the heat-treated product in water, filter and dry to obtain carbon-based single-atom materials.

[0011] Further, in step (1), the template agent is a precipitated salt or commercially available sodium chloride; the precipitated salt is prepared by preparing a saturated solution of sodium chloride with a purity >98% and water, ensuring that the sodium chloride with a purity >98% is completely dissolved, then adding ethanol, stirring until the template salt is fully precipitated, filtering, washing with ethanol, and drying by blowing air to obtain the precipitated salt; the purity of the ethanol is >90%; the mass ratio of the ethanol to the saturated solution is 0.5-5:1.

[0012] Furthermore, in step (1), the nitrogen-containing compound includes one or more of dicyandiamine, melamine, and ammonia; the organic carbon compound includes one or more of glucose, melamine, cellulose, and citric acid; and the water-soluble metal salt is a water-soluble metal salt including any one of the metal atoms Ni, Fe, Co, Mn, Pt, Cu, Ag, and Cu.

[0013] Furthermore, in step (1), the mass ratio of the template agent, nitrogen-containing compound, organic carbon compound, and water-soluble metal salt is 8000-9000:1000-1500:600-700:2.7-60.

[0014] Furthermore, in step (1), the mixing is fully ball-milled or ground.

[0015] Furthermore, in step (2), the heat treatment is to raise the temperature from room temperature to 750-760°C at a heating rate of 4-5°C / min and then treat for 2-4 hours.

[0016] Furthermore, in step (2), the reactor is a high-temperature tubular furnace or a box furnace.

[0017] Furthermore, in step (2), the protective atmosphere includes either nitrogen or argon.

[0018] The present invention also provides a carbon-based single-atom material prepared by the aforementioned method for preparing carbon-based single-atom materials based on the melt method. When the template agent is a precipitated salt, the carbon substrate of the carbon-based single-atom material exists in a discontinuous, complete shell-like form; when the template agent is commercially available sodium chloride, the carbon substrate of the carbon-based single-atom material exists in a discontinuous, sheet-like form.

[0019] This invention also provides an application of the aforementioned carbon-based single-atom material in the fields of electrocatalysis, photocatalysis, thermocatalysis, and organic synthesis.

[0020] The beneficial effects of this invention are as follows:

[0021] This invention can reduce costs. The raw materials used in this method are inexpensive and readily available. The synthesis process is simple and easy to operate. The raw materials can be scaled up proportionally, thus enabling large-scale preparation. Furthermore, the carbon-based single-atom materials prepared by this invention have a large carbon substrate surface area and good morphology, which can meet the needs of practical applications. Attached Figure Description

[0022] Figure 1 The images show the morphology of carbon-based single-atom materials prepared in the prior art, where a is the morphology of single-atom materials on a GO substrate at a 2 μm scale, and b is the morphology of single-atom materials on a carbon substrate prepared from pyrolyzed bulk carbon at a 2 μm scale.

[0023] Figure 2 This is a SEM image of the carbon-based single-atom material at a 20 μm scale in Example 1;

[0024] Figure 3 This is a SEM image of the carbon-based single-atom material at a 20 μm scale in Example 2;

[0025] Figure 4 This is a SEM image of the carbon-based single-atom material at a 50 μm scale in Example 3;

[0026] Figure 5 This is a SEM image of the carbon-based single-atom material at a 40 μm scale in Example 4;

[0027] Figure 6 This is a SEM image of the carbon-based single-atom material at a 200 μm scale in Example 5;

[0028] Figure 7 This is a SEM image of the carbon-based single-atom material at a 500 μm scale in Example 6;

[0029] Figure 8 This is a SEM image of the carbon-based single-atom material at a 400 μm scale in Example 7;

[0030] Figure 9 This is a SEM image of the carbon-based single-atom material at a 100 μm scale in Example 8. Detailed Implementation

[0031] The simplified process for preparing carbon-based single-atom materials in this invention is as follows:

[0032] Prepare a saturated solution of template salt and water, ensuring that the template salt is completely dissolved. Add ethanol with a purity >90% at a mass ratio of 1:0.5 to 5, preferably 1:0.9 to 1.5. Stir until the template salt is fully precipitated, filter, wash with ethanol, and dry by blowing air to obtain the template agent.

[0033] A template agent, a nitrogen-containing compound, an organic carbon compound, and a water-soluble metal salt are mixed together to obtain a precursor. The precursor is then placed in a reactor and heat-treated under a protective atmosphere to obtain a heat-treated product. The heat-treated product is then dispersed in water, filtered, and dried to obtain a carbon-based single-atom material.

[0034] In this invention, the template agent is a precipitated salt or commercially available sodium chloride. The nitrogen-containing compound preferably includes one or more of dicyandiamine, melamine, and ammonia, more preferably dicyandiamine. In this invention, the organic carbon compound preferably includes one or more of glucose, melamine, cellulose, and citric acid, more preferably glucose. In this invention, the water-soluble metal salt preferably includes one or more of nickel acetate tetrahydrate, nickel chloride, and nickel nitrate, more preferably nickel acetate tetrahydrate. In this invention, the water is preferably deionized water, the mixing is thorough ball milling / grinding, and the reaction furnace is a high-temperature tube furnace / box furnace.

[0035] The specific preparation method of the precipitated salt in this invention is as follows: sodium chloride with a purity >98% and water are prepared into a saturated solution to ensure that the sodium chloride is completely dissolved. Ethanol with a purity >90% is added at a mass ratio of 1:0.5 to 5, preferably 1:0.9 to 1.5. The mixture is stirred until the template salt is fully precipitated, filtered, washed with ethanol, and dried by blowing air to obtain the precipitated salt.

[0036] In this invention, the preferred mass ratio of the template agent, nitrogen-containing compound, organic carbon compound, and water-soluble metal salt is 8000–9000:1000–1500:600–700:2.7–60, more preferably 8500:1200:620:2.7–60. In this invention, when the water-soluble metal salt is preferably nickel acetate tetrahydrate and the organic carbon compound is preferably glucose, the preferred mass ratio of the organic carbon compound to the water-soluble metal salt is 620:2.7–60.

[0037] In this invention, the heat treatment temperature is preferably 750–760°C, the rate of heating from room temperature to the heat treatment temperature is preferably 4–5°C / min, and the time is preferably 2–4 hours. In this invention, the heat treatment is preferably carried out in a high-temperature tube furnace. The heat treatment is preferably carried out under a protective atmosphere, which preferably includes nitrogen or argon, and more preferably argon.

[0038] Example 1

[0039] Sodium chloride with a purity >98% was used as the template salt and water was mixed to prepare a saturated solution. The template salt was ensured to be completely dissolved. Ethanol with a purity >90% was added at a mass ratio of 1:1. The mixture was stirred until the template salt was fully separated. The solution was then filtered, washed with ethanol, and dried by blowing air to obtain the template agent.

[0040] Mix 8.5g template agent, 1.2g dicyandiamine, 0.62g glucose and 12mg nickel acetate tetrahydrate together and ball mill thoroughly to obtain the precursor;

[0041] The aforementioned precursor was then placed in a high-temperature tube furnace and heated to 760°C at a rate of 4°C / min under an Ar atmosphere. The temperature was then maintained for 3 hours to obtain the heat-treated product.

[0042] The heat-treated product was then dispersed in deionized water, filtered, and dried to obtain carbon-based single-atom materials. The final SEM image of the carbon-based single-atom materials is shown below. Figure 2 As shown.

[0043] Example 2

[0044] Sodium chloride with a purity >98% was used as the template salt and water was mixed to prepare a saturated solution, ensuring that the template salt was completely dissolved. Ethanol with a purity >90% was added at a mass ratio of 1:0.5, and the mixture was stirred until the template salt was fully separated. The solution was then filtered, washed with ethanol, and dried by blowing air to obtain the template agent.

[0045] Mix 8g template agent, 1g dicyandiamine, 0.6g glucose, and 2.7mg nickel acetate tetrahydrate together and ball mill thoroughly to obtain the precursor;

[0046] The aforementioned precursor was then placed in a high-temperature tube furnace and heated to 750°C at a rate of 4°C / min under an Ar atmosphere. The temperature was then maintained for 2 hours to obtain the heat-treated product.

[0047] The heat-treated product was then dispersed in deionized water, filtered, and dried to obtain carbon-based single-atom materials. The final SEM image of the carbon-based single-atom materials is shown below. Figure 3 As shown.

[0048] Example 3

[0049] Sodium chloride with a purity >98% was used as the template salt and water was mixed to prepare a saturated solution, ensuring that the template salt was completely dissolved. Ethanol with a purity >90% was added at a mass ratio of 1:5, and the mixture was stirred until the template salt was fully separated. The solution was then filtered, washed with ethanol, and dried by blowing air to obtain the template agent.

[0050] Mix 9g template agent, 1.5g dicyandiamine, 0.7g glucose and 60mg nickel acetate tetrahydrate together and grind thoroughly to obtain the precursor;

[0051] The aforementioned precursor was then placed in a high-temperature tube furnace and heated to 750°C at a rate of 4°C / min under an Ar atmosphere. The temperature was then maintained for 2 hours to obtain the heat-treated product.

[0052] The heat-treated product was then dispersed in deionized water, filtered, and dried to obtain carbon-based single-atom materials. The final SEM image of the carbon-based single-atom materials is shown below. Figure 4 As shown.

[0053] Example 4

[0054] Sodium chloride with a purity >98% was used as the template salt and water was mixed to prepare a saturated solution, ensuring that the template salt was completely dissolved. Ethanol with a purity >90% was added at a mass ratio of 1:5, and the mixture was stirred until the template salt was fully separated. The solution was then filtered, washed with ethanol, and dried by blowing air to obtain the template agent.

[0055] Mix 9g template agent, 1.4g melamine, 0.65g glucose and 60mg nickel acetate tetrahydrate together and grind thoroughly to obtain the precursor;

[0056] The aforementioned precursor was then placed in a box furnace and heated to 750°C at a rate of 4°C / min under a N2 atmosphere. The temperature was maintained for 2 hours to obtain the heat-treated product.

[0057] The heat-treated product was then dispersed in deionized water, filtered, and dried to obtain carbon-based single-atom materials. The final SEM image of the carbon-based single-atom materials is shown below. Figure 5 As shown.

[0058] Example 5

[0059] The template agent used was commercially available sodium chloride, and the remaining steps were the same as in Example 1. The final SEM image of the carbon-based single-atom material is shown below. Figure 6 As shown.

[0060] Example 6

[0061] The template agent used was commercially available sodium chloride, and the remaining steps were the same as in Example 2. The final SEM image of the carbon-based single-atom material is shown below. Figure 7 As shown.

[0062] Example 7

[0063] The template agent used was commercially available sodium chloride, and the remaining steps were the same as in Example 3. The final SEM image of the carbon-based single-atom material is shown below. Figure 8 As shown.

[0064] Example 8

[0065] The template agent used was commercially available sodium chloride, and the remaining steps were the same as in Example 4. The final SEM image of the carbon-based single-atom material is shown below. Figure 9 As shown.

[0066] By observing the SEM images of the carbon-based single-atom materials prepared in Examples 1-4, such as... Figure 2-5As shown, the carbon-based single-atom materials prepared by this method using salt precipitation exist in a discontinuous, complete shell-like form. By observing the SEM images of the carbon-based single-atom materials prepared in Examples 5-8, as shown... Figure 6-9 As shown, the carbon-based single-atom materials prepared using commercial sodium chloride according to this method exist in a discontinuous, intact shell-like form. The carbon-based single-atom materials prepared in Examples 1-8 of this invention have a large surface area and good morphology, which is beneficial for practical applications.

[0067] Furthermore, the method used in this application can utilize inexpensive raw materials, has a simple synthesis process, and can scale up the raw materials proportionally to achieve large-scale synthesis, making it applicable to industrial production.

[0068] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention, and all such modifications or substitutions should be covered within the scope of the claims of the present invention.

Claims

1. A method for preparing carbon-based single-atom materials based on a melt method, characterized in that, Includes the following steps: (1) The template agent, nitrogen-containing compound, organic carbon compound and water-soluble metal salt are mixed together to obtain the precursor; (2) The precursor is placed in a reactor and heat-treated under a protective atmosphere to obtain the heat-treated product; (3) Disperse the heat-treated product in water, filter and dry it to obtain carbon-based single-atom materials; In step (1), the template agent is a precipitated salt; the precipitated salt is prepared by preparing a saturated solution of sodium chloride with a purity >98% and water, ensuring that the sodium chloride has a purity >98%, then adding ethanol, stirring until the template salt is fully precipitated, filtering, washing with ethanol, and drying by blowing air to obtain the precipitated salt; the purity of the ethanol is >90%; the mass ratio of ethanol to the saturated solution is 0.5-5:1; In step (1), the nitrogen-containing compound includes one or more of dicyandiamine, melamine, and ammonia; the organic carbon compound includes one or more of glucose, melamine, cellulose, and citric acid; and the water-soluble metal salt is a water-soluble metal salt including any one of Ni, Fe, Co, Mn, Pt, Cu, and Ag. In step (1), the mass ratio of the template agent, nitrogen-containing compound, organic carbon compound, and water-soluble metal salt is 8000~9000:1000~1500:600~700:2.7~60; In step (1), the mixing is performed by ball milling or grinding until fully incorporated; In step (2), the heat treatment is to raise the temperature from room temperature to 750-760℃ at a heating rate of 4-5℃ / min and then treat for 2-4 hours.

2. The method for preparing carbon-based single-atom materials based on a melt method according to claim 1, characterized in that, In step (2), the reactor is a high-temperature tubular furnace or a box furnace.

3. The method for preparing carbon-based single-atom materials based on a melt method according to claim 1, characterized in that, In step (2), the protective atmosphere includes either nitrogen or argon.

4. A carbon-based single-atom material prepared using the method for preparing carbon-based single-atom materials based on the melt method as described in any one of claims 1-3, characterized in that, When the template agent is a precipitated salt, the carbon-based single-atom material carbon substrate exists in a discontinuous, intact shell-like form.

5. An application of the carbon-based single-atom material as described in claim 4 in the fields of electrocatalysis, photocatalysis, thermocatalysis and organic synthesis.

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