A hollow structure porous carbon material based on template-free method, preparation method and application

Abstract

The present invention discloses a hollow structure porous carbon material based on a template-free method, a preparation method and an application thereof, comprising the following steps: step 1: pretreating a polymer carbon source, immersing the material in a phosphate solution for t1 time, and drying the material to obtain a phosphate-loaded polymer material; step 2: calcining the phosphate-loaded polymer material obtained in step 1 at a high temperature in an inert atmosphere to obtain the desired hollow structure porous carbon material. The present invention does not require the introduction of a template, and the pore size, surface morphology, pore structure and specific surface area of ​​the hollow structure can be regulated. The preparation method is simple, the raw materials are cheap and readily available, the cost is low, large-scale batch production can be easily achieved, and industrial application and promotion are facilitated.

Description

Technical Field

[0001] The present invention relates to the technical field of porous carbon materials, and in particular to a hollow structure porous carbon material based on a template-free method, a preparation method and an application thereof. Background Art

[0002] Hollow structure porous carbon materials have a wide range of applications in energy storage (such as supercapacitors, lithium-ion batteries, lithium-sulfur batteries, sodium-ion batteries, potassium-ion batteries, etc.), energy conversion (such as water electrolysis catalysis), electromagnetic shielding and absorption, carbon dioxide adsorption, seawater evaporation, oil-water separation, drug delivery and other fields due to their low price, high specific surface area, rich pore structure, large void space, controllable conductivity and chemical structure stability.

[0003] In recent decades, researchers have devoted themselves to preparing hollow carbon materials and exploring their applications in various fields. Currently, the methods for preparing hollow carbon materials are mainly divided into hard template method, soft template method, and template-free method. In the hard template method, hard templates commonly used include rigid components such as zeolite, silica, and metal oxides. This method is easy to control and has low cost. For example, in the patent "A negative electrode material for lithium-ion batteries and its preparation method" with publication number CN112768661A, hollow carbon spheres are prepared by introducing hard template silica into a blend of melamine and urea, followed by high-temperature calcination and acid etching. However, this method requires the use of HF, a strong acid corrosive reagent, to remove the template, making the preparation process complicated. In the soft template method, flexible structures such as surfactants and block copolymers are usually selected as templates. For example, in the patent "Preparation method of hollow carbon materials and their products" with publication number CN106082160B, biomass raw materials are used as carbon source, surfactants are used as templates, and the hydrothermal method and soft template method are combined to obtain hollow carbon materials through high-temperature calcination. This method can obtain hollow carbon materials with different morphologies by changing the type of carbon source, but there is a problem that the pore size is difficult to control. The current method for preparing hollow carbon materials based on the template-free method mainly uses carbonization of hollow carbon precursors, which has great limitations. Although there are many methods for preparing hollow structure carbon materials, the existing process methods generally have problems such as cumbersome steps and poor controllability of the morphology, structure and size of hollow carbon materials. In addition, the above methods are difficult to achieve effective regulation of the pore structure and elemental composition while preparing the hollow structure, and it is impossible to obtain dual regulation of the material morphology and structural composition. Summary of the Invention

[0004] In view of the problems existing in the prior art, the present invention provides a hollow structure porous carbon material based on a template-free method, which has a simple method and easily controllable size, as well as a preparation method and application.

[0005] The technical solution adopted in the present invention is:

[0006] A method for preparing a hollow structure porous carbon material based on a template-free method comprises the following steps:

[0007] Step 1: Pre-treat the polymer carbon source, immerse it in a phosphate solution for t1 time, and then dry it to obtain a phosphate-loaded polymer material;

[0008] Step 2: The phosphate-loaded polymer material obtained in step 1 is calcined at high temperature in an inert atmosphere to obtain the desired hollow structure porous carbon material.

[0009] Furthermore, the phosphate ester is a mixture of one or two or more of tricresyl phosphate, ditolyl phosphate, triphenyl phosphate, trimethyl phosphate, triethyl phosphate, tripropyl phosphate, triisobutyl phosphate, tri-n-butyl phosphate, di-n-butyl phosphate, trihydroxy phosphate, toluene diphenyl phosphate, triisopropylbenzene phosphate, dibutylphenyl phosphate, monobutylphenyl phosphate, and cyclohexanehexol phosphate in any proportion.

[0010] Furthermore, the polymer carbon source is one or a mixture of two or more of polymer foam, natural fiber, chemical fiber, and fiber products in any proportion;

[0011] Polymer foams include melamine formaldehyde foam, polyurethane foam, polyvinyl alcohol foam, polystyrene foam, phenolic foam, and polyolefin foam; natural fibers include silk, wool fiber, cotton fiber, hemp fiber, and bacterial cellulose; chemical fibers include absorbent cotton, polyamide fiber, cellulose acetate, polyester, and spandex; fiber products include cellulose-based paper and cotton cloth, or a mixture of two or more in any proportion.

[0012] Furthermore, the calcination system in step 2 is as follows: keeping warm at 100-200°C for 30-120 minutes; then keeping warm at 300-500°C for 30-120 minutes, and finally keeping warm at 600-1000°C for 1-8 hours; the heating rate during the heating process is 1-10°C / min.

[0013] Furthermore, the pretreatment in step 1 is to sequentially perform ultrasonic treatment with water and ethanol, followed by washing and drying;

[0014] The process of ultrasonic treatment is as follows:

[0015] First, ultrasonic treatment is performed in water for 10 to 180 minutes, and then ultrasonic treatment is performed in anhydrous ethanol for 10 to 180 minutes.

[0016] Furthermore, in step 1, the immersion temperature is 20-60° C., and the immersion time t1 is 0.5-50 h.

[0017] Furthermore, the concentration of the phosphate solution in step 1 is 0.1 μM to 5 M, and the solvent is one or a mixture of two or more of water, methanol, ethanol, propanol, acetone, ether, benzene, toluene, and chloroform in any proportion.

[0018] Furthermore, the atmosphere during the calcination process in step 2 is an argon atmosphere or a nitrogen atmosphere.

[0019] A hollow structure porous carbon material, wherein the carbon material is a three-dimensional structure or a two-dimensional structure formed by cross-linking one or more of the following: fiber, spherical, and rod-like shapes; the hollow structure size is 1 to 500 μm; the fiber, spherical, and rod-like structures have micropores and mesopores on the surface, with a pore size range of 0.1 to 30 nm; the carbon material is doped with oxygen and phosphorus atoms, and the BET specific surface area is 100 to 2500 m 2 g -1 .

[0020] An application of a hollow structure porous carbon material, wherein the carbon material is used for supercapacitors, lithium-ion batteries, lithium-sulfur batteries, sodium-ion batteries, potassium-ion batteries, water electrolysis catalysis, electromagnetic shielding and absorption, carbon dioxide adsorption, seawater evaporation, oil-water separation, and drug delivery.

[0021] The beneficial effects of the present invention are:

[0022] (1) The preparation process of the present invention does not require the introduction of a template, thus avoiding cumbersome steps and the use of strong acid and strong base corrosive reagents;

[0023] (2) The pore size of the hollow structure of the carbon material in the present invention can be controlled by regulating the loading amount of the phosphate material;

[0024] (3) The surface morphology, pore structure and specific surface area of ​​the carbon material of the present invention can be controlled by regulating the loading amount of the phosphate material in the precursor and the calcination conditions;

[0025] (4) The preparation method of the present invention is simple to operate, and the raw materials are cheap and easily available, so the cost is low, and large-scale batch production can be easily achieved, which is convenient for industrial application and promotion. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 Schematic diagram of the preparation method of the present invention.

[0027] Figure 2 This is an SEM image of the hollow structure porous carbon material obtained in Example 1 of the present invention.

[0028] Figure 3 This is the nitrogen adsorption-desorption curve of the hollow structure porous carbon material obtained in Example 1 of the present invention.

[0029] Figure 4 This is the pore size distribution curve of the hollow structure porous carbon material obtained in Example 1 of the present invention.

[0030] Figure 5 The constant current charge and discharge curves of the hollow structure porous carbon material obtained in Example 1 of the present invention at different current densities when used in a supercapacitor.

[0031] Figure 6 This is an SEM image of the hollow structure porous carbon material obtained in Example 2 of the present invention.

[0032] Figure 7 This is an SEM image of the hollow structure porous carbon material obtained in Example 3 of the present invention.

[0033] Figure 8 This is the nitrogen adsorption-desorption curve of the hollow structure porous carbon material obtained in Example 3 of the present invention.

[0034] Figure 9 This is the pore size distribution curve of the hollow structure porous carbon material obtained in Example 3 of the present invention.

[0035] Figure 10 This is an SEM image of the hollow structure porous carbon material obtained in Example 4 of the present invention. DETAILED DESCRIPTION

[0036] The present invention will be further described below with reference to the accompanying drawings and specific embodiments.

[0037] like Figure 1 A template-free method for preparing a porous carbon material with a hollow structure comprises the following steps: first, utilizing the electrostatic interaction between a phosphate material and a polymer to load the phosphate material onto the polymer. A further high-temperature calcination stage breaks unstable bonds in the polymer, softening it. Subsequently, the phosphate material catalyzes the thermal decomposition of the polymer, rapidly releasing a large amount of gas. This exerts a strong outward expansion force on the softened polymer, causing the polymer skeleton to expand to form a hollow structure, resulting in a porous carbon material with a hollow structure.

[0038] Step 1: Pre-treat the polymer carbon source, immerse it in a phosphate solution for t1 time, and then dry it to obtain a phosphate-loaded polymer material;

[0039] The preprocessing process is as follows:

[0040] The samples were ultrasonically treated with water and ethanol in sequence, and then washed and dried;

[0041] The process of ultrasonic treatment is as follows:

[0042] First, ultrasonic treatment is performed in water for 10 to 180 minutes, and then ultrasonic treatment is performed in anhydrous ethanol for 10 to 180 minutes.

[0043] The polymer carbon source is foam: including melamine formaldehyde foam, polyurethane foam, polyvinyl alcohol foam, polystyrene foam, phenolic foam, polyolefin foam; natural fiber: including silk, wool fiber, cotton fiber, hemp fiber, bacterial cellulose; chemical fiber: including absorbent cotton, polyamide fiber, cellulose acetate, polyester, spandex; fiber products: including cellulose-based paper, cotton cloth, or a mixture of one or two or more in any proportion.

[0044] The phosphate ester is a mixture of one or more of tricresyl phosphate, dicresyl phosphate, triphenyl phosphate, trimethyl phosphate, triethyl phosphate, tripropyl phosphate, triisobutyl phosphate, tri-n-butyl phosphate, di-n-butyl phosphate, trihydroxy phosphate, diphenyl methyl phosphate, triisopropylphenyl phosphate, dibutylphenyl phosphate, monobutylphenyl phosphate, and cyclohexanehexol phosphate, in any proportion. The concentration of the phosphate ester solution is 0.1 μM to 5 M, and the solvent is one or more of water, methanol, ethanol, propanol, acetone, ether, benzene, toluene, and chloroform, in any proportion. The immersion temperature is 20 to 60°C, and the immersion time t1 is 0.5 to 50 hours.

[0045] Step 2: The phosphate-loaded polymer material obtained in step 1 is calcined at high temperature in an inert atmosphere to obtain the desired hollow structure porous carbon material.

[0046] The calcination process is as follows: hold at 100-200°C for 30-120 minutes; then hold at 300-500°C for 30-120 minutes; and finally hold at 600-1000°C for 1-8 hours. The heating rate during the heating process is 1-10°C / min. The calcination atmosphere is either argon or nitrogen.

[0047] The carbon material is a three-dimensional or two-dimensional structure formed by cross-linking one or more of the following: fiber, spherical, or rod-like structures; the hollow structure size is 1 to 500 μm; the fiber, spherical, or rod-like structure has micropores and mesopores on its surface, with a pore size range of 0.1 to 30 nm; the carbon material is doped with oxygen and phosphorus atoms, and the BET specific surface area is 100 to 2500 m 2 g -1 .

[0048] Carbon materials are used in supercapacitors, lithium-ion batteries, lithium-sulfur batteries, sodium-ion batteries, potassium-ion batteries, water electrolysis catalysis, electromagnetic shielding and absorption, carbon dioxide adsorption, seawater evaporation, oil-water separation, and drug delivery.

[0049] This invention utilizes a phosphate ester material as a pore-forming agent and a polymer material as a carbon source, combining an impregnation method with a pyrolysis method to produce a hollow porous carbon material. The phosphate ester material, suitable as a flame retardant, can catalyze and assist the polymer carbon source in producing a large amount of non-combustible gaseous components under high-temperature calcination conditions. This invention eliminates the need for a template and utilizes the catalytic effect of the phosphate ester material on the polymer carbon source during pyrolysis to rapidly release a large amount of gas within the material, producing the hollow carbon material.

[0050] First, a phosphate material is introduced into the polymer carbon source, which can catalyze the pyrolysis of the polymer during high-temperature calcination to produce a large amount of gas. During the pyrolysis process, the unstable bonds of the polymer at the low-temperature stage break, causing the polymer to soften first. Subsequently, the phosphate material catalyzes the pyrolysis of the polymer and rapidly releases a large amount of gas. A strong outward expansion force is generated on the softened polymer, causing the polymer skeleton to expand to form a hollow structure. Since the preparation principle of the hollow structure carbon material is "softening-blowing", except for the hollow structure formed inside the skeleton, the micromorphology of the polymer-derived hollow structure carbon material basically retains the micromorphology of the precursor. The amount of gas released by pyrolysis can be controlled by adjusting the loading amount of the phosphate material, and the size of the hollow structure of the corresponding carbon material can be effectively controlled. While the method of the present invention obtains the hollow structure carbon material, the pyrolysis gas will also form a large number of pore structures on the surface of the carbon material and introduce phosphorus and oxygen heteroatoms. By adjusting the loading amount of the phosphate material, the size, pore structure and heteroatom doping of the hollow structure of the carbon material can be controlled accordingly.

[0051] Example 1

[0052] A method for preparing a hollow structure porous carbon material based on a template-free method comprises the following steps:

[0053] Step 1: The melamine formaldehyde foam is first subjected to secondary water ultrasonic treatment for 30 minutes, then ultrasonicated in anhydrous ethanol for 30 minutes, and dried for use; the cleaned melamine formaldehyde foam is immersed in a 4 μM cyclohexanehexol phosphate aqueous solution at room temperature of 25°C for 15 hours, and dried to obtain cyclohexanehexol phosphate-loaded melamine formaldehyde foam.

[0054] Step 2: Place the cyclohexanehexanol-loaded melamine formaldehyde foam obtained in step 1 in an inert atmosphere, heat it to 150°C at a heating rate of 5°C / min, and keep it warm for 60 minutes; then heat it to 400°C at a heating rate of 5°C / min, and keep it warm for 60 minutes; heat it to 900°C at a heating rate of 5°C / min and keep it warm for 2 hours for high-temperature calcination, and after cooling, a hollow structure porous carbon material can be obtained.

[0055] Example 2

[0056] A method for preparing a hollow structure porous carbon material based on a template-free method comprises the following steps:

[0057] Step 1: The melamine formaldehyde foam is first subjected to secondary water ultrasonic treatment for 30 minutes, then ultrasonicated in anhydrous ethanol for 30 minutes, and dried for use; the cleaned melamine formaldehyde foam is immersed in a 2 μM cyclohexanehexol phosphate aqueous solution at room temperature of 25°C for 15 hours, and dried to obtain cyclohexanehexol phosphate-loaded melamine formaldehyde foam.

[0058] Step 2: Place the cyclohexanehexanol-loaded melamine formaldehyde foam obtained in step 1 in an inert atmosphere, heat it to 150°C at a heating rate of 5°C / min, and keep it warm for 60 minutes; then heat it to 400°C at a heating rate of 5°C / min, and keep it warm for 60 minutes; heat it to 900°C at a heating rate of 5°C / min and keep it warm for 2 hours for high-temperature calcination, and after cooling, a hollow structure porous carbon material can be obtained.

[0059] Example 3

[0060] A method for preparing a hollow structure porous carbon material based on a template-free method comprises the following steps:

[0061] Step 1: The filter paper is first subjected to secondary water ultrasonic treatment for 30 minutes, then ultrasonicated in anhydrous ethanol for 30 minutes, and dried for use; the washed filter paper is immersed in a 50 μM cyclohexane hexamethylenetetradecanoate aqueous solution at room temperature of 25°C for 15 hours, and dried to obtain the cyclohexane hexamethylenetetradecanoate-loaded filter paper.

[0062] Step 2: Place the cyclohexanehexanol-loaded filter paper obtained in step 1 in an inert atmosphere, heat it to 150°C at a heating rate of 5°C / min, and keep it warm for 60 minutes; then heat it to 400°C at a heating rate of 5°C / min, and keep it warm for 60 minutes; heat it to 900°C at a heating rate of 5°C / min and keep it warm for 2 hours for high-temperature calcination. After cooling, a hollow structure porous carbon material can be obtained.

[0063] Example 4

[0064] A method for preparing a hollow structure porous carbon material based on a template-free method comprises the following steps:

[0065] Step 1: The absorbent cotton is first treated with secondary water ultrasonic treatment for 30 minutes, then ultrasonicated in anhydrous ethanol for 30 minutes, and dried for use; the cleaned absorbent cotton is immersed in a 50 μM cyclohexanehexaol phosphate aqueous solution, soaked at room temperature of 25°C for 15 hours, and dried to obtain cyclohexanehexaol phosphate-loaded absorbent cotton.

[0066] Step 2: Place the cyclohexanehexanol-loaded absorbent cotton obtained in step 1 in an inert atmosphere, heat it to 150°C at a heating rate of 5°C / min, and keep it warm for 60 minutes; then heat it to 400°C at a heating rate of 5°C / min, and keep it warm for 60 minutes; heat it to 900°C at a heating rate of 5°C / min and keep it warm for 2 hours for high-temperature calcination. After cooling, a hollow structure porous carbon material can be obtained.

[0067] Example 5

[0068] A method for preparing a hollow structure porous carbon material based on a template-free method comprises the following steps:

[0069] Step 1: The polyurethane foam is first subjected to secondary water ultrasonic treatment for 30 minutes, then ultrasonicated in anhydrous ethanol for 30 minutes, and dried for use; the cleaned polyurethane foam is immersed in a 4 μM cyclohexanehexanol phosphate aqueous solution, immersed at room temperature of 25°C for 15 hours, and dried to obtain a cyclohexanehexanol phosphate-loaded polyurethane foam.

[0070] Step 2: Place the cyclohexanehexanol-loaded polyurethane foam obtained in step 1 in an inert atmosphere, heat it to 150°C at a heating rate of 5°C / min, and keep it warm for 60 minutes; then heat it to 400°C at a heating rate of 5°C / min, and keep it warm for 60 minutes; heat it to 900°C at a heating rate of 5°C / min and keep it warm for 2 hours for high-temperature calcination, and after cooling, a hollow structure porous carbon material can be obtained.

[0071] Example 6

[0072] A method for preparing a hollow structure porous carbon material based on a template-free method comprises the following steps:

[0073] Step 1: The polyvinyl alcohol foam is first subjected to secondary water ultrasonic treatment for 30 minutes, then ultrasonicated in anhydrous ethanol for 30 minutes, and dried for use; the washed polyvinyl alcohol foam is immersed in a 50 μM cyclohexanehexanol phosphate aqueous solution, immersed at room temperature of 25°C for 15 hours, and dried to obtain cyclohexanehexanol phosphate-loaded polyvinyl alcohol foam.

[0074] Step 2: Place the cyclohexanehexanol-loaded polyvinyl alcohol foam obtained in step 1 in an inert atmosphere, heat it to 150°C at a heating rate of 5°C / min, and keep it warm for 60 minutes; then heat it to 400°C at a heating rate of 5°C / min, and keep it warm for 60 minutes; heat it to 900°C at a heating rate of 5°C / min and keep it warm for 2 hours for high-temperature calcination. After cooling, a hollow structure porous carbon material can be obtained.

[0075] Example 7

[0076] A method for preparing a hollow structure porous carbon material based on a template-free method comprises the following steps:

[0077] Step 1: The cotton cloth is first subjected to secondary water ultrasonic treatment for 30 minutes, then ultrasonicated in anhydrous ethanol for 30 minutes, and dried for use; the cleaned cotton cloth is immersed in a 50 μM cyclohexanehexaol phosphate aqueous solution, soaked at room temperature of 25°C for 15 hours, and dried to obtain cyclohexanehexaol phosphate-loaded cotton cloth.

[0078] Step 2: Place the cyclohexanehexanol-loaded cotton fiber obtained in step 1 in an inert atmosphere, heat it to 150°C at a heating rate of 5°C / min, and keep it warm for 60 minutes; then heat it to 400°C at a heating rate of 5°C / min, and keep it warm for 60 minutes; heat it to 900°C at a heating rate of 5°C / min and keep it warm for 2 hours for high-temperature calcination. After cooling, a hollow structure porous carbon material can be obtained.

[0079] Example 8

[0080] A method for preparing a hollow structure porous carbon material based on a template-free method comprises the following steps:

[0081] Step 1: The cellulose-based paper is first subjected to secondary water ultrasonic treatment for 30 minutes, then ultrasonicated in anhydrous ethanol for 30 minutes, and dried for use; the cleaned cellulose-based paper is immersed in a 50 μM trihydroxyphosphate aqueous solution at room temperature of 25°C for 15 hours, and dried to obtain trihydroxyphosphate-loaded cellulose-based paper.

[0082] Step 2: Place the trihydroxy-loaded cellulose-based paper obtained in step 1 in an inert atmosphere, heat it to 150°C at a heating rate of 5°C / min, and keep it warm for 60 minutes; then heat it to 400°C at a heating rate of 5°C / min, and keep it warm for 60 minutes; heat it to 900°C at a heating rate of 5°C / min and keep it warm for 2 hours for high-temperature calcination. After cooling, a hollow structure porous carbon material can be obtained.

[0083] Example 9

[0084] A method for preparing a hollow structure porous carbon material based on a template-free method comprises the following steps:

[0085] Step 1: The bacterial cellulose is first subjected to secondary water ultrasonic treatment for 30 minutes, then ultrasonicated in anhydrous ethanol for 30 minutes, and dried for use; the washed bacterial cellulose is immersed in a 50 μM cyclohexanehexol phosphate aqueous solution, soaked at room temperature of 25°C for 15 hours, and dried to obtain cyclohexanehexol phosphate-loaded bacterial cellulose.

[0086] Step 2: Place the cyclohexanehexol-loaded bacterial cellulose obtained in step 1 in an inert atmosphere, heat it to 150°C at a heating rate of 5°C / min, and keep it warm for 60 minutes; then heat it to 400°C at a heating rate of 5°C / min, and keep it warm for 60 minutes; heat it to 900°C at a heating rate of 5°C / min and keep it warm for 2 hours for high-temperature calcination, and after cooling, a hollow structure porous carbon material can be obtained.

[0087] Example 10

[0088] A method for preparing a hollow structure porous carbon material based on a template-free method comprises the following steps:

[0089] Step 1: The polystyrene foam is first subjected to secondary water ultrasonic treatment for 10 minutes, then ultrasonicated in anhydrous ethanol for 10 minutes, and dried for use; the cleaned polystyrene foam is immersed in a 1M tricresyl phosphate solution at room temperature of 25°C for 15 hours, and dried to obtain tricresyl phosphate-loaded polyethylene foam.

[0090] Step 2: Place the tritolyl phosphate-loaded polyethylene foam obtained in step 1 in an inert atmosphere, heat it to 100°C at a heating rate of 10°C / min, and keep it warm for 30 minutes; then heat it to 300°C at a heating rate of 10°C / min, and keep it warm for 30 minutes; heat it to 900°C at a heating rate of 10°C / min and keep it warm for 1 hour for high-temperature calcination. After cooling, a hollow structure porous carbon material can be obtained.

[0091] Example 11

[0092] A method for preparing a hollow structure porous carbon material based on a template-free method comprises the following steps:

[0093] Step 1: The melamine formaldehyde foam is first subjected to secondary water ultrasonic treatment for 120 minutes, then ultrasonicated in anhydrous ethanol for 120 minutes, and dried for use; the cleaned melamine formaldehyde foam is immersed in a 2M cyclohexanehexol phosphate propanol solution at room temperature of 25°C for 15 hours, and dried to obtain the cyclohexanehexol phosphate-loaded melamine formaldehyde foam.

[0094] Step 2: Place the melamine formaldehyde foam loaded with cyclohexanehexanol phosphate obtained in step 1 in an inert atmosphere, heat it to 200°C at a heating rate of 1°C / min, and keep it warm for 120 minutes; then heat it to 500°C at a heating rate of 10°C / min, and keep it warm for 120 minutes; heat it to 900°C at a heating rate of 1°C / min and keep it warm for 4 hours for high-temperature calcination, and after cooling, a hollow structure porous carbon material can be obtained.

[0095] Example 12

[0096] A method for preparing a hollow structure porous carbon material based on a template-free method comprises the following steps:

[0097] Step 1: The phenolic foam is first subjected to secondary water ultrasonic treatment for 30 minutes, then ultrasonicated in anhydrous ethanol for 30 minutes, and dried for use; the cleaned phenolic foam is immersed in a 500 μM ditolyl phosphate benzene solution at 40°C for 0.5 hours, and dried to obtain a ditolyl phosphate-loaded phenolic foam.

[0098] Step 2: Place the ditolyl phosphate-loaded phenolic foam obtained in step 1 in an inert atmosphere, heat it to 150°C at a heating rate of 5°C / min, and keep it warm for 60 minutes; then heat it to 400°C at a heating rate of 5°C / min, and keep it warm for 60 minutes; heat it to 900°C at a heating rate of 5°C / min and keep it warm for 2 hours for high-temperature calcination. After cooling, a hollow structure porous carbon material can be obtained.

[0099] Example 13

[0100] A method for preparing a hollow structure porous carbon material based on a template-free method comprises the following steps:

[0101] Step 1: The polyolefin foam is first subjected to secondary water ultrasonic treatment for 30 minutes, then ultrasonicated in anhydrous ethanol for 30 minutes, and dried for use; the cleaned polyolefin foam is immersed in a 0.1 μM triphenyl phosphate ether solution at 25° C. for 10 hours, and dried to obtain a triphenyl phosphate-loaded polyolefin foam.

[0102] Step 2: Place the triphenyl phosphate-loaded polyolefin foam obtained in step 1 in an inert atmosphere, heat it to 150°C at a heating rate of 5°C / min, and keep it warm for 60 minutes; then heat it to 400°C at a heating rate of 5°C / min, and keep it warm for 60 minutes; heat it to 900°C at a heating rate of 5°C / min and keep it warm for 2 hours for high-temperature calcination. After cooling, a hollow structure porous carbon material can be obtained.

[0103] Example 14

[0104] A method for preparing a hollow structure porous carbon material based on a template-free method comprises the following steps:

[0105] Step 1: The polyamide fiber is first subjected to secondary water ultrasonic treatment for 30 minutes, then ultrasonicated in anhydrous ethanol for 30 minutes, and dried for use; the washed polyamide fiber is immersed in a 5 μM triethyl phosphate acetone solution, immersed at 25°C for 10 hours, and dried to obtain triethyl phosphate-loaded polyamide fiber.

[0106] Step 2: Place the triethyl phosphate-loaded polyamide fiber obtained in step 1 in an inert atmosphere, heat it to 150°C at a heating rate of 5°C / min, and keep it warm for 60 minutes; then heat it to 400°C at a heating rate of 5°C / min, and keep it warm for 60 minutes; heat it to 900°C at a heating rate of 5°C / min and keep it warm for 2 hours for high-temperature calcination. After cooling, a hollow structure porous carbon material can be obtained.

[0107] Example 15

[0108] A method for preparing a hollow structure porous carbon material based on a template-free method comprises the following steps:

[0109] Step 1: Cellulose acetate is first subjected to secondary water ultrasonic treatment for 30 minutes, then ultrasonicated in anhydrous ethanol for 30 minutes, and dried for use; the washed cellulose acetate is immersed in a 10 μM methanol solution of toluene diphenyl phosphate, immersed at 25°C for 10 hours, and dried to obtain toluene diphenyl phosphate-loaded cellulose acetate.

[0110] Step 2: Place the cellulose acetate loaded with toluene diphenyl phosphate obtained in step 1 in an inert atmosphere, heat it to 150°C at a heating rate of 5°C / min, and keep it warm for 60 minutes; then heat it to 400°C at a heating rate of 5°C / min, and keep it warm for 60 minutes; heat it to 600°C at a heating rate of 5°C / min and keep it warm for 1 hour for high-temperature calcination. After cooling, a hollow structure porous carbon material can be obtained.

[0111] Example 16

[0112] A method for preparing a hollow structure porous carbon material based on a template-free method comprises the following steps:

[0113] Step 1: The natural fiber is first subjected to secondary water ultrasonic treatment for 30 minutes, then ultrasonicated in anhydrous ethanol for 30 minutes, and dried for use; the washed natural fiber is immersed in a 10 μM cyclohexanehexaol phosphate ethanol solution, soaked at 25°C for 15 hours, and dried to obtain cyclohexanehexaol phosphate-loaded natural fiber.

[0114] Step 2: Place the cyclohexanehexanol phosphate-loaded natural fiber obtained in step 1 in an inert atmosphere, heat it to 150°C at a heating rate of 5°C / min, and keep it warm for 60 minutes; then heat it to 400°C at a heating rate of 5°C / min, and keep it warm for 60 minutes; heat it to 800°C at a heating rate of 5°C / min and keep it warm for 4 hours for high-temperature calcination. After cooling, a hollow structure porous carbon material can be obtained.

[0115] Example 17

[0116] A method for preparing a hollow structure porous carbon material based on a template-free method comprises the following steps:

[0117] Step 1: The chemical fiber is first subjected to secondary water ultrasonic treatment for 30 minutes, then ultrasonicated in anhydrous ethanol for 30 minutes, and dried for use; the washed chemical fiber is immersed in a toluene solution of cyclohexanehexaol phosphate with a concentration of 10 μM, immersed at 25°C for 15 hours, and dried to obtain a chemical fiber loaded with cyclohexanehexaol phosphate.

[0118] Step 2: Place the cyclohexanehexanol phosphate-loaded chemical fiber obtained in step 1 in an inert atmosphere, heat it to 150°C at a heating rate of 5°C / min, and keep it warm for 60 minutes; then heat it to 400°C at a heating rate of 5°C / min, and keep it warm for 60 minutes; heat it to 1000°C at a heating rate of 5°C / min and keep it warm for 8 hours for high-temperature calcination. After cooling, a hollow structure porous carbon material can be obtained.

[0119] Example 18

[0120] A method for preparing a hollow structure porous carbon material based on a template-free method comprises the following steps:

[0121] Step 1: The printing paper is first subjected to secondary water ultrasonic treatment for 30 minutes, then ultrasonicated in anhydrous ethanol for 30 minutes, and dried for later use; the cleaned printing paper is immersed in a 1M triisopropylphenyl phosphate chloroform solution at 25°C for 15 hours, and dried to obtain triisopropylphenyl phosphate-loaded printing paper.

[0122] Step 2: Place the triisopropylphenyl phosphate-loaded printing paper obtained in step 1 in an inert atmosphere, heat it to 150°C at a heating rate of 5°C / min, and keep it warm for 60 minutes; then heat it to 400°C at a heating rate of 5°C / min, and keep it warm for 60 minutes; heat it to 900°C at a heating rate of 5°C / min and keep it warm for 2 hours for high-temperature calcination. After cooling, a hollow structure porous carbon material can be obtained.

[0123] Example 19

[0124] A method for preparing a hollow structure porous carbon material based on a template-free method comprises the following steps:

[0125] Step 1: The melamine formaldehyde foam is first subjected to secondary water ultrasonic treatment for 30 minutes, then ultrasonicated in anhydrous ethanol for 30 minutes, and dried for use; the cleaned melamine formaldehyde foam is immersed in a 1M dibutylphenyl phosphate aqueous solution at 25°C for 15 hours, and dried to obtain dibutylphenyl phosphate-loaded melamine formaldehyde foam.

[0126] Step 2: Place the dibutylphenyl phosphate-loaded melamine formaldehyde foam obtained in step 1 in an inert atmosphere, heat it to 150°C at a heating rate of 5°C / min, and keep it warm for 60 minutes; then heat it to 400°C at a heating rate of 5°C / min, and keep it warm for 60 minutes; heat it to 900°C at a heating rate of 5°C / min and keep it warm for 2 hours for high-temperature calcination, and after cooling, a hollow structure porous carbon material can be obtained.

[0127] Example 20

[0128] A method for preparing a hollow structure porous carbon material based on a template-free method comprises the following steps:

[0129] Step 1: The melamine formaldehyde foam is first subjected to secondary water ultrasonic treatment for 180 minutes, then ultrasonicated in anhydrous ethanol for 180 minutes, and dried for use; the cleaned melamine formaldehyde foam is immersed in a 100 μM monobutyl phenyl phosphate aqueous solution at 25° C. for 15 hours, and dried to obtain monobutyl phenyl phosphate-loaded melamine formaldehyde foam.

[0130] Step 2: Place the monobutylphenyl phosphate-loaded melamine formaldehyde foam obtained in step 1 in an inert atmosphere, heat it to 150°C at a heating rate of 5°C / min, and keep it warm for 60 minutes; then heat it to 400°C at a heating rate of 5°C / min, and keep it warm for 60 minutes; heat it to 900°C at a heating rate of 5°C / min and keep it warm for 2 hours for high-temperature calcination, and after cooling, a hollow structure porous carbon material can be obtained.

[0131] Example 21

[0132] A method for preparing a hollow structure porous carbon material based on a template-free method comprises the following steps:

[0133] Step 1: The melamine formaldehyde foam is first subjected to secondary water ultrasonic treatment for 30 minutes, then ultrasonicated in anhydrous ethanol for 30 minutes, and dried for use; the cleaned melamine formaldehyde foam is immersed in a 4 μM cyclohexanehexol phosphate aqueous solution at room temperature of 25°C for 50 hours, and dried to obtain cyclohexanehexol phosphate-loaded melamine formaldehyde foam.

[0134] Step 2: Place the cyclohexanehexanol-loaded melamine formaldehyde foam obtained in step 1 in an inert atmosphere, heat it to 150°C at a heating rate of 5°C / min, and keep it warm for 60 minutes; then heat it to 400°C at a heating rate of 5°C / min, and keep it warm for 60 minutes; heat it to 900°C at a heating rate of 5°C / min and keep it warm for 2 hours for high-temperature calcination, and after cooling, a hollow structure porous carbon material can be obtained.

[0135] Example 22

[0136] A method for preparing a hollow structure porous carbon material based on a template-free method comprises the following steps:

[0137] Step 1: The melamine formaldehyde foam is first subjected to secondary water ultrasonic treatment for 30 minutes, then ultrasonicated in anhydrous ethanol for 30 minutes, and dried for use; the cleaned melamine formaldehyde foam is immersed in a 4 μM cyclohexanehexol phosphate aqueous solution at 60° C. for 15 hours, and dried to obtain cyclohexanehexol phosphate-loaded melamine formaldehyde foam.

[0138] Step 2: Place the cyclohexanehexanol-loaded melamine formaldehyde foam obtained in step 1 in an inert atmosphere, heat it to 150°C at a heating rate of 5°C / min, and keep it warm for 60 minutes; then heat it to 400°C at a heating rate of 5°C / min, and keep it warm for 60 minutes; heat it to 900°C at a heating rate of 5°C / min and keep it warm for 2 hours for high-temperature calcination, and after cooling, a hollow structure porous carbon material can be obtained.

[0139] Example 23

[0140] A method for preparing a hollow structure porous carbon material based on a template-free method comprises the following steps:

[0141] Step 1: The melamine formaldehyde foam is first subjected to secondary water ultrasonic treatment for 30 minutes, then ultrasonicated in anhydrous ethanol for 30 minutes, and dried for use; the cleaned melamine formaldehyde foam is immersed in a 5M cyclohexanehexol phosphate aqueous solution at room temperature of 25°C for 15 hours, and dried to obtain cyclohexanehexol phosphate-loaded melamine formaldehyde foam.

[0142] Step 2: Place the cyclohexanehexanol-loaded melamine formaldehyde foam obtained in step 1 in an inert atmosphere, heat it to 150°C at a heating rate of 5°C / min, and keep it warm for 60 minutes; then heat it to 400°C at a heating rate of 5°C / min, and keep it warm for 60 minutes; heat it to 900°C at a heating rate of 5°C / min and keep it warm for 2 hours for high-temperature calcination, and after cooling, a hollow structure porous carbon material can be obtained.

[0143] Example 24

[0144] A method for preparing a hollow structure porous carbon material based on a template-free method comprises the following steps:

[0145] Step 1: The silk is first subjected to secondary water ultrasonic treatment for 180 minutes, then ultrasonicated in anhydrous ethanol for 180 minutes, and dried for use; the cleaned silk is immersed in a 100 μM trimethyl phosphate methanol solution at 25°C for 15 hours, and dried to obtain trimethyl phosphate-loaded silk.

[0146] Step 2: Place the trimethyl phosphate-loaded silk obtained in step 1 in an inert atmosphere, heat it to 150°C at a heating rate of 5°C / min, and keep it warm for 60 minutes; then heat it to 400°C at a heating rate of 5°C / min, and keep it warm for 60 minutes; heat it to 900°C at a heating rate of 5°C / min and keep it warm for 2 hours for high-temperature calcination. After cooling, a hollow structure porous carbon material can be obtained.

[0147] Example 25

[0148] A method for preparing a hollow structure porous carbon material based on a template-free method comprises the following steps:

[0149] Step 1: The wool fiber is first subjected to secondary water ultrasonic treatment for 180 minutes, then ultrasonicated in anhydrous ethanol for 180 minutes, and dried for use; the washed wool fiber is immersed in a 300 μM tripropyl phosphate ethanol solution, soaked at 25°C for 15 hours, and dried to obtain tripropyl phosphate-loaded wool fiber.

[0150] Step 2: Place the tripropyl phosphate-loaded wool fiber obtained in step 1 in an inert atmosphere, heat it to 150°C at a heating rate of 5°C / min, and keep it warm for 60 minutes; then heat it to 400°C at a heating rate of 5°C / min, and keep it warm for 60 minutes; heat it to 900°C at a heating rate of 5°C / min and keep it warm for 2 hours for high-temperature calcination. After cooling, a hollow structure porous carbon material can be obtained.

[0151] Example 26

[0152] A method for preparing a hollow structure porous carbon material based on a template-free method comprises the following steps:

[0153] Step 1: The cotton fiber is first subjected to secondary water ultrasonic treatment for 180 minutes, then ultrasonicated in anhydrous ethanol for 180 minutes, and dried for use; the cleaned cotton fiber is immersed in a 500 μM triisobutyl phosphate aqueous solution, soaked at 25°C for 15 hours, and dried to obtain triisobutyl phosphate-loaded cotton fiber.

[0154] Step 2: Place the triisobutyl phosphate-loaded cotton fiber obtained in step 1 in an inert atmosphere, heat it to 150°C at a heating rate of 5°C / min, and keep it warm for 60 minutes; then heat it to 400°C at a heating rate of 5°C / min, and keep it warm for 60 minutes; heat it to 900°C at a heating rate of 5°C / min and keep it warm for 2 hours for high-temperature calcination. After cooling, a hollow structure porous carbon material can be obtained.

[0155] Example 27

[0156] A method for preparing a hollow structure porous carbon material based on a template-free method comprises the following steps:

[0157] Step 1: The hemp fiber is first subjected to a secondary water ultrasonic treatment for 180 minutes, then ultrasonicated in anhydrous ethanol for 180 minutes, and dried for use; the washed hemp fiber is immersed in a 100 μM tri-n-butyl phosphate aqueous solution at 25° C. for 15 hours, and dried to obtain tri-n-butyl phosphate-loaded hemp fiber.

[0158] Step 2: Place the hemp fiber loaded with tri-n-butyl phosphate obtained in step 1 in an inert atmosphere, heat it to 150°C at a heating rate of 5°C / min, and keep it warm for 60 minutes; then heat it to 400°C at a heating rate of 5°C / min, and keep it warm for 60 minutes; heat it to 900°C at a heating rate of 5°C / min and keep it warm for 2 hours for high-temperature calcination, and after cooling, a hollow structure porous carbon material can be obtained.

[0159] Example 28

[0160] A method for preparing a hollow structure porous carbon material based on a template-free method comprises the following steps:

[0161] Step 1: The polyester is first subjected to secondary water ultrasonic treatment for 180 minutes, then ultrasonicated in anhydrous ethanol for 180 minutes, and dried for use; the cleaned polyester is immersed in a 100 μM di-n-butyl phosphate aqueous solution at 25° C. for 15 hours, and dried to obtain di-n-butyl phosphate-loaded polyester.

[0162] Step 2: Place the polyester loaded with di-n-butyl phosphate obtained in step 1 in an inert atmosphere, heat it to 150°C at a heating rate of 5°C / min, and keep it warm for 60 minutes; then heat it to 400°C at a heating rate of 5°C / min, and keep it warm for 60 minutes; heat it to 900°C at a heating rate of 5°C / min and keep it warm for 2 hours for high-temperature calcination. After cooling, a hollow structure porous carbon material can be obtained.

[0163] Example 29

[0164] A method for preparing a hollow structure porous carbon material based on a template-free method comprises the following steps:

[0165] Step 1: The spandex is first subjected to secondary water ultrasonic treatment for 180 minutes, then ultrasonicated in anhydrous ethanol for 180 minutes, and dried for use; the washed spandex is immersed in a 100 μM cyclohexane hexamethylene phosphate aqueous solution at a concentration of 25° C. for 15 hours, and dried to obtain cyclohexane hexamethylene phosphate-loaded spandex.

[0166] Step 2: Place the spandex loaded with cyclohexanehexanol phosphate obtained in step 1 in an inert atmosphere, heat it to 150°C at a heating rate of 5°C / min, and keep it warm for 60 minutes; then heat it to 400°C at a heating rate of 5°C / min, and keep it warm for 60 minutes; heat it to 900°C at a heating rate of 5°C / min and keep it warm for 2 hours for high-temperature calcination, and after cooling, a hollow structure porous carbon material can be obtained.

[0167] In order to illustrate the performance of the materials, the materials obtained in some examples were tested, and the characterization instruments used are as follows:

[0168] Scanning electron microscope: Model H-7650, manufactured by Hitachi; Surface area and porosity analyzer: Model BELSORP MAXⅡ, manufactured by Japan Microchip; Shanghai Chenhua electrochemical workstation: Model CHI760, manufactured by Shanghai Chenhua Company.

[0169] Figure 2 This is an SEM image of the hollow structure porous carbon material obtained in Example 1 of the present invention. It can be seen from the figure that the carbon material obtained in Example 1 is a three-dimensional porous cross-linked structure with obvious bulging on the skeleton surface. The hollow structure of the material can be observed from the rupture of the bulge, and the size of the hollow structure is about 16μm. Figure 3 This is the nitrogen adsorption-desorption curve of the hollow structure porous carbon material obtained in Example 1. It can be seen from the figure that the specific surface area of ​​the obtained carbon material is 772m 2 g -1 . Figure 4 This is the pore size distribution curve of the hollow structure porous carbon material obtained in Example 1 of the present invention. It can be seen from the figure that the pore size of the carbon material is mainly distributed below 2 nm, indicating that the pores in the material are mainly micropores. Figure 5 The constant current charge-discharge curves of the hollow structure porous carbon material obtained in the embodiment of the present invention at different current densities when used to prepare supercapacitors. It can be seen from the figure that the obtained carbon material has a constant current charge-discharge curve at 1Ag -1 The specific capacitance is 171F g at a current density of -1 , and has good rate performance.

[0170] Figure 6 This is an SEM image of the hollow porous carbon material obtained in Example 2 of the present invention. The image shows a three-dimensional porous cross-linked structure. The hollow structure of the skeleton can be observed through the fractures in the skeleton, and the size of the hollow structure is approximately 9 μm. The size of the hollow structure of the carbon material in Example 2 is significantly smaller than that of the precursor-derived carbon material with a higher cyclohexanol phosphate loading, indicating that the size of the hollow structure of the carbon material can be effectively controlled by regulating the cyclohexanol phosphate loading.

[0171] Figure 7 This is an SEM image of the hollow structure porous carbon material obtained in Example 3 of the present invention. It can be seen from the image that the carbon material is a fiber stacking structure, and the hollow structure of the material can be observed from the broken fibers. Figure 8 This is the nitrogen adsorption-desorption curve of the hollow structure porous carbon material obtained in Example 3. It can be seen from the figure that the specific surface area of ​​the carbon material is 956m 2 g -1 .

[0172] Figure 10 This is an SEM image of the hollow structure porous carbon material obtained in Example 4 of the present invention. It can be seen from the image that the carbon material is a disordered fiber entanglement structure, and the hollow structure of the material can be observed from the broken fibers.

[0173] The preparation method of the present invention does not require the introduction of a template, avoids the use of cumbersome steps and strong acid and strong alkali corrosive reagents, and the pore size of the hollow position of the hollow structure porous carbon material can be controllably regulated by regulating the loading amount of the phosphate material. The morphology, pore structure and specific surface area of ​​the surface of the hollow structure porous carbon material can be regulated by regulating the loading amount of the phosphate material in the precursor and the calcination conditions. The porous carbon material contains oxygen and phosphorus heteroatom doping and rich micropores and mesoporous structures, has a high specific surface area, and can be used in supercapacitors, lithium ion batteries, lithium sulfur batteries, sodium ion batteries, potassium ion batteries, water electrolysis catalysis, electromagnetic shielding and absorption, carbon dioxide adsorption, seawater evaporation, oil-water separation, drug delivery and other fields. The preparation method is simple, the raw materials are cheap and easy to obtain, the cost is low, and it is easy to achieve large-scale batch production, which is convenient for industrial application and promotion.

Claims

1. A method for preparing a hollow structure porous carbon material based on a template-free method, characterized in that: The following steps are involved: Step 1: Pre-treat the polymer carbon source, immerse it in a phosphate solution for t1 time, and then dry it to obtain a phosphate-loaded polymer material; the polymer carbon source is one or a mixture of two or more of polymer foam, natural fiber, chemical fiber, and fiber products in any proportion; the polymer foam includes melamine formaldehyde foam, polyurethane foam, polyvinyl alcohol foam, polystyrene foam, phenolic foam, and polyolefin foam; the natural fiber includes silk, wool fiber, cotton fiber, hemp fiber, and bacterial cellulose; the chemical fiber includes absorbent cotton, polyamide fiber, cellulose acetate, polyester, and spandex; the fiber product includes one or two of cellulose-based paper and cotton cloth A mixture of one or more of the following in any proportion; the phosphate ester is a mixture of one or two or more of tricresyl phosphate, ditolyl phosphate, triphenyl phosphate, trimethyl phosphate, triethyl phosphate, tripropyl phosphate, triisobutyl phosphate, tri-n-butyl phosphate, di-n-butyl phosphate, trihydroxy phosphate, toluene diphenyl phosphate, triisopropylbenzene phosphate, dibutylphenyl phosphate, monobutylphenyl phosphate, and cyclohexane hexol phosphate in any proportion; the concentration of the phosphate ester solution is 0.1 μM to 5 M, and the solvent is one or a mixture of two or more of the following in any proportion: water, methanol, ethanol, propanol, acetone, ether, benzene, toluene, and chloroform; Step 2: The phosphate-loaded polymer material obtained in step 1 is calcined at high temperature in an inert atmosphere to obtain the desired hollow structure porous carbon material; the calcination system is as follows: keep warm at 100-200°C for 30-120 minutes; then keep warm at 300-500°C for 30-120 minutes, and finally keep warm at 600-1000°C for 1-8 hours; the heating rate during the heating process is 1-10°C / min; the carbon material is a three-dimensional structure or a two-dimensional structure formed by cross-linking one or more of the following: fibrous, spherical, and rod-like structures; the hollow structure size is 1-500 μm; the surface of the fibrous, spherical, and rod-like structures has micropores and mesoporous structures with a pore size range of 0.1-30 nm; the carbon material is doped with oxygen and phosphorus atoms, and the BET specific surface area is 100-2500 m 2 g -1 .

2. The method for preparing a hollow structure porous carbon material based on a template-free method according to claim 1, characterized in that: The pretreatment in step 1 is to perform ultrasonic treatment with water and ethanol in sequence, followed by washing and drying; the ultrasonic treatment process is as follows: first, ultrasonic treatment is performed in water for 10 to 180 minutes, and then ultrasonic treatment is performed in anhydrous ethanol for 10 to 180 minutes.

3. The method for preparing a hollow structure porous carbon material based on a template-free method according to claim 1, characterized in that: In the step 1, the immersion temperature is 20-60° C., and the immersion time t1 is 0.5-50 h.

4. The method for preparing a hollow structure porous carbon material based on a template-free method according to claim 1, characterized in that: The atmosphere during the calcination process in step 2 is an argon atmosphere or a nitrogen atmosphere.

5. Use of the hollow structure porous carbon material obtained by the preparation method according to any one of claims 1 to 4, characterized in that: The carbon material is used in supercapacitors, lithium-ion batteries, lithium-sulfur batteries, sodium-ion batteries, potassium-ion batteries, water electrolysis catalysis, electromagnetic shielding and absorption, carbon dioxide adsorption, seawater evaporation, oil-water separation, and drug delivery.

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