Method for loading metal carbide on porous carbon

Abstract

The invention is applicable to the technical field of composite materials, and provides a method for loading metal carbide on porous carbon, which comprises the following steps: preparing a porous carbon material; loading of metal carbides; and activation and treatment: treating the product obtained in the step (2) at high temperature, and promoting crystal growth and interaction of the metal carbide through heat treatment. According to the method for loading the metal carbide on the porous carbon provided by the embodiment of the invention, the steps of activation and treatment are added, and the treatment is carried out at high temperature, so that the crystal growth and interaction of the metal carbide can be further promoted, and the catalytic activity and stability are further improved.

Description

Technical Field

[0001] The invention belongs to the technical field of composite materials, and in particular relates to a method for loading metal carbides on porous carbon. Background Art

[0002] Porous carbon loaded with metal carbide is a composite material, which is a composite structure formed by porous carbon as a matrix and metal carbide as an active ingredient loaded on the carbon material. The material has the following characteristics: High specific surface area: Porous carbon material has an extremely high specific surface area, providing a large amount of active surface, which is conducive to the loading of metal carbide and the improvement of reaction activity; Good chemical stability: Metal carbide has good chemical stability on porous carbon loading and can resist the influence of conditions such as oxidation, corrosion and high temperature; Good conductivity: Porous carbon as a matrix has good conductivity, which is conducive to the electron transfer and catalytic activity of metal carbide in electrochemical reactions; Regulating pore size and pore structure: By regulating the preparation conditions of carbon materials and the loading method of metal carbide, the pore size and pore structure of porous carbon loaded with metal carbide can be controlled, thereby adjusting its adsorption performance and catalytic activity.

[0003] Based on the characteristics of porous carbon-loaded metal carbides, they have a wide range of applications in many fields, including: Catalysts: Porous carbon-loaded metal carbides have high catalytic activity, selectivity and stability as catalysts, and can be used in electrochemical catalysis, gas separation, oxidation reactions and other fields; Energy storage and conversion: Porous carbon-loaded metal carbides have important applications in energy storage and conversion fields such as lithium-ion batteries, supercapacitors and fuel cells, and can improve electrochemical performance and energy storage capacity; Adsorption materials: Porous carbon-loaded metal carbides have high specific surface area and pore volume, and can be used as adsorption materials in environmental and energy fields such as wastewater treatment, gas adsorption and separation; Sensors: Porous carbon-loaded metal carbides have good electrical conductivity and high sensitivity in the sensor field, and can be used in gas sensing, electrochemical sensing and biosensing.

[0004] However, different metal carbides have different catalytic activities and stabilities, and the ratio and interaction between carbon materials and metal carbides may affect their catalytic performance. Summary of the invention

[0005] The purpose of the embodiments of the present invention is to provide a method for loading metal carbides on porous carbon, aiming to solve the problems raised in the above background technology.

[0006] The embodiment of the present invention is implemented as follows: a method for loading metal carbide on porous carbon comprises the following steps:

[0007] (1) Preparation of porous carbon materials: Selecting an organic polymer or a natural carbon source as a raw material, pyrolyzing and carbonizing the raw material in an inert gas to obtain a carbon material, and activating the carbon material with a chemical activator or a physical activator to form a carbon material with a porous structure;

[0008] (2) Loading of metal carbides: Select a metal salt, dissolve it in a solvent to form a metal salt solution, and use a deposition method to bring the metal salt solution into contact with the carbon material, so that the metal carbide is deposited on the surface of the carbon material through thermal decomposition;

[0009] (3) Activation and treatment: The product obtained in step (2) is treated at high temperature to promote the crystal growth and interaction of metal carbides through heat treatment.

[0010] Preferably, the mass ratio of the carbon material to the metal salt is 7-9:1-3.

[0011] Preferably, in step (1), the organic polymer is polystyrene or polypropylene, and the natural carbon source is lignin or bagasse.

[0012] Preferably, in step (1), the inert gas is nitrogen or argon, the pyrolysis carbonization temperature is 500-1000° C., the heating rate is 5-20° C. / min, and the carbonization time is 5-10 h.

[0013] Preferably, in step (1), the chemical activator is an alkali metal salt or an acid, and the physical activator is high-temperature water vapor.

[0014] Preferably, in step (2), the metal salt is one of the nitrates of Ti, Cr, Mn, Fe and Co.

[0015] Preferably, in step (2), the specific process of the deposition method includes: dissolving a metal salt in water or ethanol to obtain a metal salt solution, mixing the metal salt solution with a carbon material to allow metal ions to contact the carbon material, adding a precipitant or an alkaline solution under stirring conditions to allow the metal ions to co-precipitate on the surface of the carbon material to form a metal hydroxide or a metal carbonate, washing the co-precipitate with water for multiple times to remove unreacted solutes and precipitants, and heat-treating the washed co-precipitate to convert it into a metal carbide;

[0016] Wherein, the precipitant is sodium carbonate, the alkaline solution is sodium hydroxide or ammonia water; the temperature of the heat treatment is 300-900° C., and the time is 5-8 hours.

[0017] Preferably, in step (3), the specific process of activation and treatment includes: placing the metal carbide composite product obtained in step (2) in a container, and ensuring uniform distribution and proper ventilation of the product; placing the product in a heat treatment device and starting a heating and temperature raising process; after reaching the target temperature, keeping the temperature to promote the crystal growth and interaction of the metal carbides; after completing the heat preservation, slowly cooling the product to room temperature;

[0018] Wherein, the heating rate is 5-10°C / min, and the target temperature is 1200-1400°C.

[0019] The method for loading metal carbides on porous carbon provided in an embodiment of the present invention adds activation and treatment steps. The treatment is performed at high temperature, which can further promote the crystal growth and interaction of the metal carbides, thereby improving the catalytic activity and stability. DETAILED DESCRIPTION

[0020] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0021] The specific implementation of the present invention is described in detail below in conjunction with specific embodiments.

[0022] Example 1

[0023] A method for loading metal carbide on porous carbon comprises the following steps:

[0024] (1) Preparation of porous carbon material: polystyrene is selected as a raw material, the raw material is pyrolyzed and carbonized in a nitrogen gas to obtain a carbon material, and the carbon material is activated by an alkali metal salt to form a carbon material with a porous structure, wherein the pyrolysis and carbonization temperature is 500° C., the heating rate is 5° C. / min, and the carbonization time is 10 h;

[0025] (2) Loading of metal carbide: selecting a metal salt, wherein the mass ratio of the carbon material to the metal salt is 7:3, dissolving the metal salt in water to obtain a metal salt solution, mixing the metal salt solution with the carbon material to allow the metal ions to contact the carbon material, and adding sodium carbonate under stirring conditions to allow the metal ions to co-precipitate on the surface of the carbon material to form a metal hydroxide or a metal carbonate, washing the co-precipitate with water for multiple times to remove unreacted solutes and precipitants, and heat-treating the washed co-precipitate to convert it into a metal carbide, wherein the heat treatment temperature is 300° C., the time is 8 hours, and the metal salt is a nitrate of Ti;

[0026] (3) Activation and treatment: placing the metal carbide composite product obtained in step (2) in a container and ensuring uniform distribution and proper ventilation of the product; placing the product in a heat treatment device and starting a heating process at a heating rate of 5°C / min; after reaching 1200°C, maintaining the temperature to promote crystal growth and interaction of the metal carbides; after completing the insulation, slowly cooling the product to room temperature.

[0027] Example 2

[0028] A method for loading metal carbide on porous carbon comprises the following steps:

[0029] (1) Preparation of porous carbon material: polypropylene is selected as a raw material, the raw material is pyrolyzed and carbonized in an argon gas to obtain a carbon material, and the carbon material is activated by an acid to form a carbon material with a porous structure, wherein the pyrolysis and carbonization temperature is 800° C., the heating rate is 10° C. / min, and the carbonization time is 7 h;

[0030] (2) Loading of metal carbide: selecting a metal salt, wherein the mass ratio of the carbon material to the metal salt is 8:2, dissolving the metal salt in ethanol to obtain a metal salt solution, mixing the metal salt solution with the carbon material to allow the metal ions to contact the carbon material, and adding sodium hydroxide under stirring conditions to allow the metal ions to co-precipitate on the surface of the carbon material to form a metal hydroxide or a metal carbonate, washing the co-precipitate with water for multiple times to remove unreacted solutes and precipitants, and heat-treating the washed co-precipitate to convert it into a metal carbide, wherein the heat treatment temperature is 600° C. and the time is 6 hours, and the metal salt is selected from nitrate of Cr;

[0031] (3) Activation and treatment: placing the metal carbide composite product obtained in step (2) in a container and ensuring uniform distribution and proper ventilation of the product; placing the product in a heat treatment device and starting a heating process at a heating rate of 8°C / min; after reaching 1300°C, maintaining the temperature to promote crystal growth and interaction of the metal carbides; after completing the insulation, slowly cooling the product to room temperature.

[0032] Example 3

[0033] A method for loading metal carbide on porous carbon comprises the following steps:

[0034] (1) Preparation of porous carbon material: lignin is selected as a raw material, the raw material is pyrolyzed and carbonized in nitrogen gas to obtain a carbon material, and the carbon material is activated by an alkali metal salt to form a carbon material with a porous structure, wherein the pyrolysis and carbonization temperature is 1000° C., the heating rate is 20° C. / min, and the carbonization time is 5 h;

[0035] (2) Loading of metal carbide: selecting a metal salt, wherein the mass ratio of the carbon material to the metal salt is 9:1, dissolving the metal salt in water to obtain a metal salt solution, mixing the metal salt solution with the carbon material to allow the metal ions to contact the carbon material, and under stirring, adding ammonia water to allow the metal ions to co-precipitate on the surface of the carbon material to form a metal hydroxide or a metal carbonate, washing the co-precipitate with water for multiple times to remove unreacted solutes and precipitants, and heat-treating the washed co-precipitate to convert it into a metal carbide, wherein the heat treatment temperature is 900° C. and the time is 5 hours. The metal salt is selected from the nitrate of Mn and Mg;

[0036] (3) Activation and treatment: placing the metal carbide composite product obtained in step (2) in a container and ensuring uniform distribution and proper ventilation of the product; placing the product in a heat treatment device and starting a heating process at a heating rate of 10°C / min; after reaching 1400°C, maintaining the temperature to promote crystal growth and interaction of the metal carbides; after completing the insulation, slowly cooling the product to room temperature.

[0037] Example 4

[0038] A method for loading metal carbide on porous carbon comprises the following steps:

[0039] (1) Preparation of porous carbon material: bagasse is selected as a raw material, the raw material is pyrolyzed and carbonized in nitrogen gas to obtain a carbon material, and the carbon material is activated by high-temperature steam to form a carbon material with a porous structure, wherein the pyrolysis and carbonization temperature is 500° C., the heating rate is 5° C. / min, and the carbonization time is 10 h;

[0040] (2) Loading of metal carbide: selecting a metal salt, wherein the mass ratio of the carbon material to the metal salt is 9:1, dissolving the metal salt in ethanol to obtain a metal salt solution, mixing the metal salt solution with the carbon material to allow the metal ions to contact the carbon material, and adding sodium carbonate under stirring conditions to allow the metal ions to co-precipitate on the surface of the carbon material to form a metal hydroxide or a metal carbonate, washing the co-precipitate with water for multiple times to remove unreacted solutes and precipitants, and heat-treating the washed co-precipitate to convert it into a metal carbide, wherein the heat treatment temperature is 300° C. and the time is 8 hours, and the metal salt is selected from Fe nitrate;

[0041] (3) Activation and treatment: placing the metal carbide composite product obtained in step (2) in a container and ensuring uniform distribution and proper ventilation of the product; placing the product in a heat treatment device and starting a heating process at a heating rate of 5°C / min; after reaching 1200°C, maintaining the temperature to promote crystal growth and interaction of the metal carbides; after completing the insulation, slowly cooling the product to room temperature.

[0042] Example 5

[0043] A method for loading metal carbide on porous carbon comprises the following steps:

[0044] (1) Preparation of porous carbon material: lignin is selected as a raw material, the raw material is pyrolyzed and carbonized in nitrogen gas to obtain a carbon material, and the carbon material is activated by an alkali metal salt to form a carbon material with a porous structure, wherein the pyrolysis and carbonization temperature is 500° C., the heating rate is 5° C. / min, and the carbonization time is 10 h;

[0045] (2) Loading of metal carbide: selecting a metal salt, wherein the mass ratio of the carbon material to the metal salt is 8:2, dissolving the metal salt in ethanol to obtain a metal salt solution, mixing the metal salt solution with the carbon material to allow the metal ions to contact the carbon material, and adding sodium carbonate under stirring conditions to allow the metal ions to co-precipitate on the surface of the carbon material to form a metal hydroxide or a metal carbonate, washing the co-precipitate with water for multiple times to remove unreacted solutes and precipitants, and heat-treating the washed co-precipitate to convert it into a metal carbide, wherein the heat treatment temperature is 300° C. and the time is 8 hours. The metal salt is selected from Co nitrate;

[0046] (3) Activation and treatment: placing the metal carbide composite product obtained in step (2) in a container and ensuring uniform distribution and proper ventilation of the product; placing the product in a heat treatment device and starting a heating process at a heating rate of 10°C / min; after reaching 1200°C, maintaining the temperature to promote crystal growth and interaction of the metal carbides; after completing the insulation, slowly cooling the product to room temperature.

[0047] 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 in the protection scope of the present invention.

Claims

1. A method for loading metal carbides on porous carbon, characterized in that: The following steps are involved: (1) Preparation of porous carbon materials: Selecting an organic polymer or a natural carbon source as a raw material, pyrolyzing and carbonizing the raw material in an inert gas to obtain a carbon material, and activating the carbon material with a chemical activator or a physical activator to form a carbon material with a porous structure; (2) Loading of metal carbides: Select a metal salt, dissolve it in a solvent to form a metal salt solution, and use a deposition method to bring the metal salt solution into contact with the carbon material, so that the metal carbide is deposited on the surface of the carbon material through thermal decomposition; (3) Activation and treatment: The product obtained in step (2) is treated at high temperature to promote the crystal growth and interaction of metal carbides through heat treatment.

2. The method for loading metal carbides on porous carbon according to claim 1, characterized in that: The mass ratio of the carbon material to the metal salt is 7-9:1-3.

3. The method for loading metal carbides on porous carbon according to claim 1, characterized in that: In step (1), the organic polymer is polystyrene or polypropylene, and the natural carbon source is lignin or bagasse.

4. The method for loading metal carbides on porous carbon according to claim 1, characterized in that: In step (1), the inert gas is nitrogen or argon, the pyrolysis carbonization temperature is 500-1000° C., the heating rate is 5-20° C. / min, and the carbonization time is 5-10 h.

5. The method for loading metal carbides on porous carbon according to claim 1, characterized in that: In step (1), the chemical activator is an alkali metal salt or an acid, and the physical activator is high-temperature water vapor.

6. The method for loading metal carbides on porous carbon according to claim 1, characterized in that: In step (2), the metal salt is one of the nitrates of Ti, Cr, Mn, Fe and Co.

7. The method for loading metal carbides on porous carbon according to claim 1, characterized in that: In step (2), the specific process of the deposition method includes: dissolving a metal salt in water or ethanol to obtain a metal salt solution, mixing the metal salt solution with a carbon material to allow metal ions to contact the carbon material, adding a precipitant or an alkaline solution under stirring conditions to allow the metal ions to co-precipitate on the surface of the carbon material to form a metal hydroxide or a metal carbonate, washing the co-precipitate with water for multiple times to remove unreacted solutes and precipitants, and heat-treating the washed co-precipitate to convert it into a metal carbide; Wherein, the precipitant is sodium carbonate, the alkaline solution is sodium hydroxide or ammonia water; the temperature of the heat treatment is 300-900° C., and the time is 5-8 hours.

8. The method for loading metal carbides on porous carbon according to claim 1, characterized in that: In step (3), the specific process of the activation and treatment includes: placing the metal carbide composite product obtained in step (2) in a container, and ensuring uniform distribution and proper ventilation of the product; placing the product in a heat treatment device and starting a heating and temperature raising process; after reaching the target temperature, keeping the temperature to promote the crystal growth and interaction of the metal carbides; after completing the heat preservation, slowly cooling the product to room temperature; Wherein, the heating rate is 5-10°C / min, and the target temperature is 1200-1400°C.