Method for preparing self-coiled structure molybdenum disulfide / nitrogen-doped porous carbon composite material, product and application thereof

Abstract

The application provides a preparation method of a self-coiled structure molybdenum disulfide / nitrogen-doped porous carbon composite material, a product and application, high-content nitrogen-doped porous carbon material is synthesized by inducing dicyandiamide molecules to undergo a supramolecular self-assembly process, and on this basis, a hydrothermal reaction is carried out to coat molybdenum sulfide sheet layer material on the surface, and finally, a self-heating coiling treatment is carried out to form a carbon-based electrocatalyst of the self-coiled structure molybdenum disulfide / nitrogen-doped porous carbon. Compared with a high specific surface area carbon-based catalyst, high doping concentration of nitrogen atoms can provide more electron-rich properties to facilitate the adsorption of substances, and the self-coiled carbon-based material can exhibit very excellent electrochemical performance, especially in the aspect of electrochemical hydrogen production. The preparation method is simple in operation, low in preparation cost and suitable for large-scale production.

Description

Technical Field

[0001] This invention relates to the technical field of electrocatalytic hydrogen production, specifically disclosing a method for preparing a carbon-based catalyst for electrocatalytic water splitting to produce hydrogen, specifically a method for preparing a self-rolled molybdenum disulfide / nitrogen-doped porous carbon composite material, its product, and its application. Background Technology

[0002] The dwindling supply of fossil fuels and the increasing severity of environmental pollution pose significant threats to human survival and development. Finding and developing green and renewable energy sources to replace fossil fuels has become a key focus of research both domestically and internationally. H2 energy combustion produces only water, generates no pollution, and boasts 100% atom utilization, making it a highly sought-after clean and efficient energy source. Electrolysis of water using electricity to produce hydrogen is an effective method for generating H2 energy. Currently, Pt / C catalysts are commercially available, but precious metals are relatively expensive and resources are limited. Furthermore, the recyclability of these catalysts needs improvement. Therefore, seeking non-precious metal (non-metal) catalysts to replace commercial Pt / C catalysts has become a breakthrough in this field.

[0003] Nitrogen-doped porous carbon (NPC) possesses an abundant porous structure. Introducing nitrogen atoms into the porous carbon lattice allows for the formation of high-content nitrogen-containing functional groups that not only serve as active sites for orthostatic oxygen regeneration (ORR) but also introduce pseudocapacitance to enhance the capacitance of supercapacitors. Due to its high specific surface area, high conductivity, and high stability, nitrogen-doped porous carbon has promising applications in electrocatalysis. However, the heteroatom nitrogen concentration in chemically modified porous carbon materials is generally very low, especially for carbon materials requiring high-temperature calcination (e.g., 1000℃). Furthermore, high-temperature calcination is crucial for ensuring higher graphitization, higher conductivity, and superior electrocatalytic performance in carbon materials. Therefore, increasing the nitrogen doping concentration without damaging the porous carbon structure remains a significant challenge. Summary of the Invention

[0004] The purpose of this invention is to provide a method for preparing a self-rolling structure of molybdenum disulfide / nitrogen-doped porous carbon composite material.

[0005] Another object of the present invention is to provide a self-rolling molybdenum disulfide / nitrogen-doped porous carbon composite material product prepared by the above method.

[0006] Another object of the present invention is to provide an application of the above-mentioned product.

[0007] The objective of this invention is achieved through the following scheme: a method for preparing a self-coiled molybdenum disulfide / nitrogen-doped porous carbon composite material, characterized by inducing dicyandiamide molecules to undergo a supramolecular self-assembly process to synthesize a high-content nitrogen-doped porous carbon material, followed by a hydrothermal reaction to coat its surface with molybdenum disulfide sheet material, and finally, a self-heating curling treatment to form a carbon-based electrocatalyst with a self-coiled molybdenum disulfide / nitrogen-doped porous carbon structure, comprising the following steps:

[0008] Step 1: Preparation of nitrogen-doped porous carbon material: Ammonium sulfate, dicyandiamide, and glucose were used as raw materials. They were mixed in water at a mass ratio of (0.05-0.4):40:1. The water was evaporated at a temperature below 85℃ to obtain a supramolecular self-assembled white homogeneous mixture. This white substance was then transferred to a crucible and placed in a muffle furnace under N2 protection. The temperature was increased at a rate of 3.3℃ / min, and calcined at 800-1000℃ for 1 h, finally yielding a black, fluffy solid. After grinding, this became the nitrogen-doped porous carbon material.

[0009] The second step, the composite formation of molybdenum disulfide nanoparticles: 100 mg of the prepared nitrogen-doped porous carbon was taken, and sodium molybdate and thiourea were added, along with DMF solution and hydroxylamine. After ultrasonic vibration, the mixture was placed in a hydrothermal reactor and hydrothermally heated at 200°C for 12 hours, then naturally cooled. The resulting mixture was centrifuged to separate the liquid, retaining the solid powder. Deionized water and anhydrous ethanol were added for dispersion, and the powder was centrifuged and washed again. This process was repeated three times. Finally...

[0010] The third step involves drying the obtained solid powder at 70°C and then subjecting it to self-coiling treatment in a tube furnace under a nitrogen atmosphere at 350-450°C to obtain a molybdenum disulfide / nitrogen-doped porous carbon composite material with a self-coiling structure.

[0011] In the first step, the roasting temperature is 900℃.

[0012] In the first step, the nitrogen atom mass content can reach 10-35%.

[0013] Preferably, in the second step, the mass ratio of the obtained molybdenum disulfide content to the nitrogen-doped porous carbon composite material is 1:1 to 1:10.

[0014] In the third step, the optimal temperature for self-rolling in the tube furnace under nitrogen atmosphere is controlled at 400℃.

[0015] This invention provides a method for preparing a molybdenum disulfide / nitrogen-doped porous carbon composite material with a self-rolling structure. Under the action of ammonium sulfate, dicyandiamide molecules undergo a supramolecular self-assembly process to synthesize nitrogen-doped porous carbon. Based on this, glucose is used as a carbon source to introduce molybdenum disulfide sheets as new active sites into the nitrogen-doped porous carbon. Simultaneously, high-temperature heat treatment is used to roll the material, resulting in the molybdenum disulfide / nitrogen-doped porous carbon composite material. The synergistic effect of molybdenum disulfide and nitrogen atoms in this material enhances the electrocatalytic effect of nitrogen-doped graphene in the hydrogen evolution reaction (HER). Compared to large-area carbon-based catalysts, the high doping concentration of nitrogen atoms provides more electron-rich properties, which is beneficial for adsorption. This material exhibits excellent electrochemical performance, especially in electrochemical hydrogen production. The preparation method is simple to operate, and the rolling process is spontaneous, making it suitable for large-scale production.

[0016] This invention provides a self-rolling molybdenum disulfide / nitrogen-doped porous carbon composite material, prepared according to any of the methods described above.

[0017] This invention provides an application of a self-rolled molybdenum disulfide / nitrogen-doped porous carbon composite material in electrocatalytic hydrogen production.

[0018] Activity testing of carbon-based catalysts for electrocatalytic hydrogen production:

[0019] All hydrogen production catalytic activity tests were performed using a CHI-660E three-electrode electrochemical workstation. The reference electrode was an Ag / AgCl electrode, and the counter electrode was a rotating ring disk platinum electrode. 0.1–9 mg of molybdenum disulfide / nitrogen-doped porous carbon composite material and 8–200 μL of 5% (w / w) Nafion solution were ultrasonically dispersed in 1 ml of 5–50% (v / v) ethanol aqueous solution. Then, 2–30 μL of the dispersion was dropped onto the working electrode and allowed to air dry. The voltage scan rate was 1–25 mV / s, and the working electrode rotation speed was 200–3500 rpm.

[0020] This invention utilizes the inductive effect of ammonium sulfate to directly self-assemble dicyandiamide molecules into nitrogen-doped porous carbon materials. A hydrothermal reaction is then carried out to coat the surface with molybdenum disulfide sheets, followed by a thermal curling process to ultimately form a carbon-based electrocatalyst of molybdenum disulfide / nitrogen-doped porous carbon. This material possesses high nitrogen content and a curled self-assembled structure, showing promising applications in electrochemical hydrogen production.

[0021] Compared with existing technologies, the technical feature of this invention is that it uses ammonium sulfate, dicyandiamide, and glucose as raw materials to self-assemble into a high-nitrogen-content porous carbon material with a nanoporous structure. Then, molybdenum disulfide sheets are deposited onto the surface of the nitrogen-doped porous carbon via a hydrothermal method, and the high-temperature thermal curling effect ultimately forms a carbon-based electrocatalyst of molybdenum disulfide / nitrogen-doped porous carbon. This material has a high nitrogen content and a curled self-assembled structure, and through the synergistic effect of molybdenum disulfide and nitrogen atoms, it enhances the electrocatalytic effect of nitrogen-doped graphene in the hydrogen evolution reaction (HER). Attached Figure Description

[0022] Figure 1 This is an evaluation of the performance of the nitrogen-rich carbon-based catalyst obtained in Example 1 for electrocatalytic hydrogen production. Detailed Implementation

[0023] This embodiment is implemented based on the technical solution of the present invention, and provides detailed implementation methods and specific operation processes. However, the scope of protection of the present invention is not limited to the following embodiment.

[0024] Example 1:

[0025] A self-rolling molybdenum disulfide / nitrogen-doped porous carbon composite material is prepared by inducing dicyandiamide molecules to undergo a supramolecular self-assembly process to synthesize a high-content nitrogen-doped porous carbon material. Based on this, a hydrothermal reaction is carried out to coat the surface with molybdenum disulfide sheets. Finally, a self-heating rolling treatment is performed to form a carbon-based electrocatalyst with a self-rolling molybdenum disulfide / nitrogen-doped porous carbon structure. The preparation method is as follows:

[0026] The first step is the preparation of nitrogen-doped porous carbon materials with high nitrogen content: ammonium sulfate, dicyandiamide and glucose are used as raw materials. They are mixed in water at a mass ratio of 0.2:40:1. The water is evaporated at 85℃ to obtain a supramolecular self-assembled white homogeneous mixture. Then, the white object is transferred to a crucible and placed in a muffle furnace under N2 protection. The heating rate is 3.3℃ / min. The temperature is raised to 900℃ and calcined for 1 h to finally obtain a black fluffy solid. After grinding, it becomes nitrogen-doped porous carbon material.

[0027] The second step, the composite formation of molybdenum disulfide nanoparticles: 100 mg of the prepared nitrogen-doped porous carbon was taken, and 3.29 mg of sodium molybdate and 4.56 mg of thiourea were added, along with 10 ml of DMF solution and 0.02 ml of hydroxylamine. After ultrasonic vibration, the mixture was placed in a hydrothermal reactor and hydrothermally heated at 200°C for 12 hours, then naturally cooled. The resulting mixture was centrifuged to separate the liquid, retaining the solid powder. Deionized water was added for dispersion, and the mixture was centrifuged and washed again, repeating this process three times. Then, anhydrous ethanol was added for centrifugation and washing, also repeated three times. Finally,

[0028] The third step involves drying the obtained solid powder at 70°C and then subjecting it to a self-coiling treatment at 400°C in a tube furnace under a nitrogen atmosphere to obtain a molybdenum disulfide / nitrogen-doped porous carbon composite material with a self-coiling structure.

[0029] The product in this embodiment serves as a carbon-based catalyst for electrocatalytic hydrogen production. The performance evaluation of the nitrogen-rich carbon-based catalyst obtained in this embodiment for electrocatalytic hydrogen production is shown in [link to documentation]. Figure 1 .

[0030] Example 2:

[0031] A self-rolling molybdenum disulfide / nitrogen-doped porous carbon composite material, prepared according to steps similar to those in Example 1, is as follows:

[0032] The first step, preparation of nitrogen-doped porous carbon material: Ammonium sulfate, dicyandiamide, and glucose were used as raw materials and mixed in water at a mass ratio of 0.05:40:1. The water was evaporated at 80℃ to obtain a supramolecular self-assembled white homogeneous mixture. Then, the white object was transferred to a crucible and placed in a muffle furnace under N2 protection. The temperature was increased at a rate of 3.3℃ / min, and the mixture was calcined at 900℃ for 1 h to obtain a black, fluffy solid. After grinding, it became the nitrogen-doped porous carbon material.

[0033] The second step, the composite formation of molybdenum disulfide nanoparticles: 100 mg of the prepared nitrogen-doped porous carbon was added, along with 6.58 mg of sodium molybdate and 9.12 mg of thiourea, 20 ml of DMF solution, and 0.04 ml of hydroxylamine. After ultrasonic vibration, the mixture was placed in a hydrothermal reactor and hydrothermally heated at 200°C for 12 hours, then naturally cooled. The resulting mixture was centrifuged to separate the liquid, retaining the solid powder. Deionized water was added for dispersion, and the mixture was centrifuged and washed again, repeating this process three times. Then, anhydrous ethanol was added for centrifugation and washing, also repeated three times. Finally,

[0034] The third step involves drying the obtained solid powder at 70°C and then subjecting it to a self-rolling treatment at 400°C in a tube furnace under a nitrogen atmosphere. This yields a molybdenum disulfide / nitrogen-doped porous carbon composite material with a self-rolling structure, which can be used as a carbon-based catalyst for electrocatalytic hydrogen production.

[0035] Example 3:

[0036] A self-rolling molybdenum disulfide / nitrogen-doped porous carbon composite material, prepared according to steps similar to those in Example 1, is as follows:

[0037] The first step is the preparation of nitrogen-doped porous carbon materials: ammonium sulfate, dicyandiamide, and glucose are used as raw materials. They are mixed in water at a mass ratio of 0.4:40:1. The water is evaporated at 80°C to obtain a supramolecular self-assembled white homogeneous mixture. Then, the white object is transferred to a crucible and placed in a muffle furnace under N2 protection. The heating rate is 3.3°C / min. The mixture is heated to 900°C and calcined for 1 h to obtain a black fluffy solid. After grinding, it becomes nitrogen-doped porous carbon material, which is used as a carbon-based electrocatalyst for hydrogen production.

[0038] The second step, the composite formation of molybdenum disulfide nanoparticles: 100 mg of the prepared nitrogen-doped porous carbon was added, along with 9.87 mg of sodium molybdate and 13.68 mg of thiourea, 30 ml of DMF solution, and 0.06 ml of hydroxylamine. After ultrasonic vibration, the mixture was placed in a hydrothermal reactor and hydrothermally heated at 200°C for 12 hours, then naturally cooled. The resulting mixture was centrifuged to separate the liquid, retaining the solid powder. Deionized water was added to disperse the powder, and it was centrifuged and washed again. This process was repeated three times. Finally,

[0039] The third step involves drying the obtained solid powder at 70°C and then subjecting it to a self-rolling treatment at 400°C in a tube furnace under a nitrogen atmosphere. This yields a molybdenum disulfide / nitrogen-doped porous carbon composite material with a self-rolling structure, which can be used as a carbon-based catalyst for electrocatalytic hydrogen production.

[0040] Activity testing of carbon-based catalysts for electrocatalytic hydrogen production:

[0041] All hydrogen production catalytic activity tests were performed using a CHI-660E three-electrode electrochemical workstation. The reference electrode was an Ag / AgCl electrode, and the counter electrode was a rotating ring disk platinum electrode. 0.1–9 mg of molybdenum disulfide / nitrogen-doped porous carbon composite material and 8–200 μL of 5% (w / w) Nafion solution were ultrasonically dispersed in 1 ml of 5–50% (v / v) ethanol aqueous solution. Then, 2–30 μL of the dispersion was dropped onto the working electrode and allowed to air dry. The voltage scan rate was 1–25 mV / s, and the working electrode rotation speed was 200–3500 rpm.

[0042] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for preparing a self-rolling molybdenum disulfide / nitrogen-doped porous carbon composite material, characterized in that, High-nitrogen-doped porous carbon materials are synthesized by inducing dicyandiamide molecules to undergo supramolecular self-assembly. Based on this, a hydrothermal reaction is carried out to coat the surface with molybdenum disulfide sheets. Finally, a self-heating curling treatment is performed to form a carbon-based electrocatalyst with a self-curled structure of molybdenum disulfide / nitrogen-doped porous carbon. The process includes the following steps: The first step is the preparation of nitrogen-doped porous carbon materials: using ammonium sulfate, dicyandiamide, and glucose as raw materials, the three are mixed in water at a mass ratio of (0.05-0.4):40:

1. The water is evaporated at a temperature below 85℃ to obtain a supramolecular self-assembled white homogeneous mixture. Then, the white homogeneous mixture is transferred to a crucible and placed in a muffle furnace under N2 protection. The heating rate is 3.3℃ / min, and the temperature is raised to 800-1000℃ for calcination and held for 1 h to finally obtain a black fluffy solid. After grinding, it becomes nitrogen-doped porous carbon material. The second step, the composite formation of molybdenum disulfide nanoparticles: 100 mg of the prepared nitrogen-doped porous carbon was taken, and sodium molybdate and thiourea were added, along with DMF solution and hydroxylamine. After ultrasonic vibration, the mixture was placed in a hydrothermal reactor and hydrothermally heated at 200°C for 12 hours, then naturally cooled. The resulting mixture was centrifuged to separate the liquid, retaining the solid powder. Deionized water and anhydrous ethanol were added for dispersion, and the powder was centrifuged and washed again. This process was repeated three times. Finally... The third step involves drying the obtained solid powder at 70°C and then subjecting it to self-coiling treatment in a tube furnace under a nitrogen atmosphere at 350-450°C to obtain a molybdenum disulfide / nitrogen-doped porous carbon composite material with a self-coiling structure.

2. The method for preparing a self-coiled molybdenum disulfide / nitrogen-doped porous carbon composite material according to claim 1, characterized in that, In the first step, the roasting temperature is 900℃.

3. The method for preparing a self-coiled molybdenum disulfide / nitrogen-doped porous carbon composite material according to claim 1, characterized in that, In the second step, the mass ratio of the obtained molybdenum disulfide content to the nitrogen-doped porous carbon composite material is 1:1 to 1:

10.

4. The method for preparing a self-coiled molybdenum disulfide / nitrogen-doped porous carbon composite material according to claim 1, characterized in that, In the third step, the self-rolling temperature of the tube furnace under nitrogen atmosphere is controlled at 400℃.

5. A method for preparing a self-rolling molybdenum disulfide / nitrogen-doped porous carbon composite material, characterized in that, Prepare according to the following steps: The first step is the preparation of nitrogen-doped porous carbon materials with high nitrogen content: ammonium sulfate, dicyandiamide and glucose are used as raw materials. They are mixed in water at a mass ratio of 0.2:40:

1. The water is evaporated at 85℃ to obtain a supramolecular self-assembled white homogeneous mixture. Then, the white homogeneous mixture is transferred to a crucible and placed in a muffle furnace under N2 protection. The heating rate is 3.3℃ / min. The temperature is raised to 900℃ and calcined for 1 h to finally obtain a black fluffy solid. After grinding, it becomes nitrogen-doped porous carbon material. The second step, the composite formation of molybdenum disulfide nanoparticles: 100 mg of the prepared nitrogen-doped porous carbon was taken, and 3.29 mg of sodium molybdate and 4.56 mg of thiourea were added, along with 10 ml of DMF solution and 0.02 ml of hydroxylamine. After ultrasonic vibration, the mixture was placed in a hydrothermal reactor and hydrothermally heated at 200°C for 12 hours, then naturally cooled. The resulting mixture was centrifuged to separate the liquid, retaining the solid powder. Deionized water was added for dispersion, and the mixture was centrifuged and washed again, repeating this process three times. Then, anhydrous ethanol was added for centrifugation and washing, also repeated three times. Finally, The third step involves drying the obtained solid powder at 70°C and then subjecting it to a self-coiling treatment at 400°C in a tube furnace under a nitrogen atmosphere to obtain a molybdenum disulfide / nitrogen-doped porous carbon composite material with a self-coiling structure.

6. A method for preparing a self-rolling molybdenum disulfide / nitrogen-doped porous carbon composite material, characterized in that, Prepare according to the following steps: The first step is the preparation of nitrogen-doped porous carbon materials: ammonium sulfate, dicyandiamide, and glucose are used as raw materials. They are mixed in water at a mass ratio of 0.05:40:

1. The water is evaporated at 80°C to obtain a supramolecular self-assembled white homogeneous mixture. Then, the white homogeneous mixture is transferred to a crucible and placed in a muffle furnace under N2 protection. The heating rate is 3.3°C / min. The mixture is heated to 900°C and calcined for 1 h to obtain a black fluffy solid. After grinding, it becomes nitrogen-doped porous carbon material. The second step, the composite formation of molybdenum disulfide nanoparticles: 100 mg of the prepared nitrogen-doped porous carbon was added, along with 6.58 mg of sodium molybdate and 9.12 mg of thiourea, 20 ml of DMF solution, and 0.04 ml of hydroxylamine. After ultrasonic vibration, the mixture was placed in a hydrothermal reactor and hydrothermally heated at 200°C for 12 hours, then naturally cooled. The resulting mixture was centrifuged to separate the liquid, retaining the solid powder. Deionized water was added for dispersion, and the mixture was centrifuged and washed again, repeating this process three times. Then, anhydrous ethanol was added for centrifugation and washing, also repeated three times. Finally, The third step involves drying the obtained solid powder at 70°C and then subjecting it to a self-coiling treatment at 400°C in a tube furnace under a nitrogen atmosphere to obtain a molybdenum disulfide / nitrogen-doped porous carbon composite material with a self-coiling structure.

7. A method for preparing a self-rolling structured molybdenum disulfide / nitrogen-doped porous carbon composite material, characterized in that, Prepare according to the following steps: The first step is the preparation of nitrogen-doped porous carbon materials: ammonium sulfate, dicyandiamide, and glucose are used as raw materials. They are mixed in water at a mass ratio of 0.4:40:

1. The water is evaporated at 80°C to obtain a supramolecular self-assembled white homogeneous mixture. Then, the white homogeneous mixture is transferred to a crucible and placed in a muffle furnace under N2 protection. The heating rate is 3.3°C / min. The mixture is heated to 900°C and calcined for 1 h to obtain a black fluffy solid. After grinding, it becomes nitrogen-doped porous carbon material. The second step, the composite formation of molybdenum disulfide nanoparticles: 100 mg of the prepared nitrogen-doped porous carbon was added, along with 9.87 mg of sodium molybdate and 13.68 mg of thiourea, 30 ml of DMF solution, and 0.06 ml of hydroxylamine. After ultrasonic vibration, the mixture was placed in a hydrothermal reactor and hydrothermally heated at 200°C for 12 hours, then naturally cooled. The resulting mixture was centrifuged to separate the liquid, retaining the solid powder. Deionized water was added to disperse the powder, and it was centrifuged and washed again. This process was repeated three times. Finally, The third step involves drying the obtained solid powder at 70°C and then subjecting it to a self-coiling treatment at 400°C in a tube furnace under a nitrogen atmosphere to obtain a molybdenum disulfide / nitrogen-doped porous carbon composite material with a self-coiling structure.

8. A self-rolling structured molybdenum disulfide / nitrogen-doped porous carbon composite material, characterized in that... Prepared according to any one of claims 1-7.

9. The application of a self-rolled molybdenum disulfide / nitrogen-doped porous carbon composite material according to claim 8 in electrocatalytic hydrogen production.

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