Self-hygroscopic-conductive synergic core-shell structure carbon-based composite material, preparation method and application thereof

Abstract

The application discloses a self-hygroscopic and conductive synergic core-shell structure carbon-based composite material, a preparation method and application thereof. The self-hygroscopic and conductive synergic core-shell structure carbon-based composite material comprises a core layer and a shell layer covering the core layer; the core layer is a conductive carbon matrix serving as a conductive framework, and the conductive carbon matrix is prepared by multiple gradient carbonization of a carbon fiber rod; the shell layer is a hygroscopic coating layer, comprising a molecular level composite system formed by a hygroscopic component through hydrogen bonds and coordination bonds, and the core layer and the shell layer form a covalent bonding interface through a silane coupling agent. The application realizes the integration and synergy of self-hygroscopic and conductive properties by constructing the core-shell structure of the conductive framework-hygroscopic coating layer, prepares the hygroscopic coating layer through a molecular level composite technology, and constructs a covalent bonding interface by using a silane coupling agent, so that the structural stability and cyclic service ability of the material are improved, H3O + is efficiently and stably generated in situ, and the oxidation and decomposition efficiency of gaseous pollutants is significantly improved.

Description

Technical Field

[0001] This invention belongs to the field of gaseous pollutant purification materials and environmental governance technology, specifically relating to a core-shell structured carbon-based composite material with both self-hygroscopic and conductive properties, its preparation method, and its application in the purification of gaseous pollutants. Background Technology

[0002] With industrial development and the widespread adoption of interior decoration, the emission and accumulation of gaseous pollutants such as formaldehyde, benzene compounds, and other VOCs have become a key issue affecting air quality and human health. These pollutants are characterized by high toxicity, difficulty in degradation, and easy diffusion. Long-term exposure can lead to respiratory diseases, gene mutations, and other health risks. Therefore, developing efficient, stable, and environmentally friendly gaseous pollutant purification technologies is of significant practical importance.

[0003] Currently, the main technologies for purifying gaseous pollutants include adsorption, photocatalytic oxidation, plasma, and catalytic combustion. However, all of these technologies have significant technical bottlenecks. For example: (1) Adsorption (such as activated carbon adsorption) can only achieve physical enrichment of pollutants and cannot completely degrade them. It is prone to adsorption saturation and secondary pollution. Moreover, the adsorption capacity is limited and the regeneration cost is high. (2) Photocatalytic oxidation (such as TiO2-based photocatalysts) depends on ultraviolet light irradiation. It has low quantum efficiency, poor visible light response, and the catalyst is prone to deactivation. In practical applications, it requires complex light source equipment, which limits its use in lightless scenarios. (3) Although plasma can generate active species such as hydroxyl radicals (·OH) to oxidize pollutants, it has high energy consumption and is prone to producing NO. x The byproducts are large and the equipment is not suitable for indoor or small-scale purification scenarios; (4) Catalytic combustion method needs to be operated under high temperature conditions (usually ≥200℃), which consumes a lot of energy and has low purification efficiency for low-concentration pollutants, making it difficult to meet the purification needs at room temperature.

[0004] To address these issues, researchers have begun to focus on purification mechanisms that generate strong oxidizing species in situ, such as generating reactive species like O3 and ·OH radicals through corona discharge (e.g., metal needle electrodes). However, O3 is prone to secondary pollution, and ·OH radicals have a short lifetime (<10) in dry environments. -6 (s), with limited purification efficiency. In comparison, hydrated hydrogen ions (H3O) +As a highly reactive oxidizing species, hydrated hydrogen ions possess advantages such as high oxidation potential, good reaction selectivity, and no secondary pollution, demonstrating great potential in the degradation of gaseous pollutants. For example, patents CN119143257A and CN119372672A both mention the preparation process of hydrated hydrogen ions; the article Angew. Chem. Int. Ed. 2025, 64, e202424067 mentions the excellent bactericidal effect of hydrated hydrogen ions. However, existing technologies also have some technical bottlenecks, including:

[0005] (1) Single function. Currently, although materials with self-hygroscopic function (such as calcium chloride, carboxylates, sulfonates, etc.) can effectively adsorb environmental moisture within a wide humidity range, they are usually insulators or semiconductors with extremely poor conductivity, and cannot achieve efficient electrolysis of water molecules and the release of active species (such as H3O) under the action of an electric field. + In situ generation of [materials]. Conversely, highly conductive materials (such as carbon fibers, graphene, and metal-based composites), while possessing excellent electron transport capabilities, generally lack self-hygroscopic properties and require external water sources or high-humidity environments to sustain the electrochemical reaction. For example, publications CN114575157A and CN115448288A only possess water absorption capabilities but cannot achieve self-hygroscopicity;

[0006] (2) Interfacial instability caused by differences in physical properties. Self-hygroscopic materials often have hydrophilic, swelling, and ion migration properties, while conductive materials (especially carbon-based materials) are usually hydrophobic or have low surface energy structures. There are significant differences between the two in terms of wettability, coefficient of thermal expansion, and mechanical strength. Currently common composite material preparation strategies (such as mechanical mixing, physical impregnation, and in-situ deposition) are often difficult to achieve molecular-level tight bonding between the two phases, which can easily lead to uneven component distribution, weak interfacial bonding, and rapid performance degradation during long-term use, especially under high humidity or electric field cycling conditions. In addition, the excessive introduction of hygroscopic components can easily clog the structure of conductive materials, reducing electron transport efficiency and specific surface area; while the surface modification of conductive components may mask hygroscopic active sites, weakening their moisture capture ability. How to achieve efficient synergy of hygroscopic and conductive functions in a limited space has become the core challenge of material design.

[0007] Therefore, how to construct a carbon-based composite material with synergistic self-hygroscopic and conductive properties to achieve H3O without an external water source is crucial. + The in-situ and stable generation of pollutants, while improving the structural stability and cycle performance of materials, is a key technical problem that urgently needs to be solved in the field of gaseous pollutant purification technology. Summary of the Invention

[0008] The main objective of this invention is to provide a self-hygroscopic and conductive synergistic core-shell structured carbon-based composite material and its preparation method, thereby overcoming the shortcomings of the prior art.

[0009] Another object of the present invention is to provide the application of the self-hygroscopic-conductive synergistic core-shell structure carbon-based composite material in the purification of gaseous pollutants.

[0010] To achieve the aforementioned objectives, the technical solution adopted by this invention includes:

[0011] The first aspect of this invention provides a self-hygroscopic-conductive synergistic core-shell structured carbon-based composite material, comprising: a core layer and a shell layer covering the core layer; wherein the core layer is a conductive carbon matrix serving as a conductive framework, the conductive carbon matrix being prepared by multiple gradient carbonization of carbon fiber rods; the shell layer is a hygroscopic coating comprising a molecular-level composite system of hygroscopic components formed by hydrogen bonds and coordination bonds, the hygroscopic components having hydrophilic functional groups, and the core layer and shell layer forming a covalently bonded interface through a silane coupling agent.

[0012] A second aspect of this invention provides a method for preparing a self-hygroscopic-conductive synergistic core-shell structured carbon-based composite material, comprising:

[0013] The original carbon fiber rods were subjected to multiple gradient carbonization processes to obtain a conductive carbon matrix that serves as a conductive framework.

[0014] A molecular-level hygroscopic wetting liquid comprising a hygroscopic component and a silane coupling agent is provided, wherein the hygroscopic component is capable of forming a molecular-level composite system through hydrogen bonds and coordination bonds, and the hygroscopic component has hydrophilic functional groups;

[0015] The conductive carbon matrix is ​​immersed in the molecular-level hygroscopic wetting liquid for molecular-level wetting and composite. By utilizing capillary action and molecular diffusion effect, the hygroscopic components and silane coupling agent penetrate to the surface of the conductive carbon matrix to achieve molecular-level composite.

[0016] A self-hygroscopic and conductive core-shell structured carbon-based composite material was prepared by interfacial bonding and shaping treatment of a conductive carbon matrix after molecular-level impregnation and composite. A moisture-absorbing coating was formed on the surface of the conductive carbon matrix, and the interfacial covalent bonding between the moisture-absorbing coating and the conductive carbon matrix was achieved through the cross-linking reaction of a silane coupling agent.

[0017] A third aspect of the present invention provides a self-hygroscopic-conductive synergistic core-shell structured carbon-based composite material prepared by the above-described preparation method.

[0018] A fourth aspect of the present invention provides the application of the self-hygroscopic-conductive synergistic core-shell structured carbon-based composite material in the purification of gaseous pollutants mediated by hydrated hydrogen ions.

[0019] Compared with the prior art, the technical solution of the present invention has the following significant advantages:

[0020] 1) This invention achieves integrated synergy of self-hygroscopic and conductive properties by constructing a core-shell structure of "conductive skeleton-hygroscopic coating". The self-hygroscopic rate of the carbon-based composite material can reach 2.5~9.0 g / (g·h) in the humidity range of 30~90%, and it can generate H3O without the need for an external water source. + It generates and provides sufficient water molecules, which solves the shortcomings of existing technologies that are limited in applicable scenarios and can meet the purification needs of low humidity environments such as dry areas in the north.

[0021] 2) The self-hygroscopic-conductive synergistic core-shell carbon-based composite material provided by the present invention has outstanding structural stability and cycle performance. Through molecular-level composite technology and covalent bonding interface design, the component shedding problem of traditional physical mixed materials is avoided. The carbon-based composite material can be cycled for 500 to 1000 times of hygroscopic-desorption, with a hygroscopic rate decay rate of ≤10%, and its cycle service capability far exceeds that of the existing technology.

[0022] 3) The self-hygroscopic and conductive synergistic core-shell structure carbon-based composite material provided by this invention exhibits excellent electrical conductivity, and H3O is generated after applying voltage. + It has high generation efficiency, and the moisture-absorbing coating can stabilize H3O. + Avoid rapid recombination;

[0023] 4) The self-hygroscopic-conductive synergistic core-shell structure carbon-based composite material provided by the present invention significantly improves the oxidation and decomposition efficiency of gaseous pollutants such as formaldehyde. The process parameters are easy to control, making it suitable for large-scale industrial production, reducing material production costs, and expanding its application potential in multiple scenarios such as indoor air purification and industrial waste gas pretreatment. Attached Figure Description

[0024] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0025] Figure 1 This is a flowchart illustrating the preparation of a self-hygroscopic-conductive synergistic core-shell structured carbon-based composite material in a typical embodiment of the present invention.

[0026] Figure 2A , Figure 2B These are scanning electron microscope images and magnified images of the original carbon fiber rods used in Embodiment 1 of the present invention.

[0027] Figure 3 These are macroscopic morphological photographs of the original carbon fiber rods used in Embodiment 1 of the present invention;

[0028] Figure 4A , Figure 4B These are scanning electron microscope images and magnified images of the carbon fiber rods after gradient carbonization in Embodiment 1 of the present invention.

[0029] Figure 5 These are macroscopic morphological photographs of carbon fiber rods after gradient carbonization in Embodiment 1 of the present invention;

[0030] Figure 6A , Figure 6B These are scanning electron microscope images and magnified images of the self-hygroscopic-conductive synergistic core-shell structure carbon-based composite material obtained after molecular-level infiltration composite, interfacial bonding and shaping treatment in Example 1 of the present invention.

[0031] Figure 7 These are macroscopic morphology photographs of the self-hygroscopic-conductive synergistic core-shell structure carbon-based composite material prepared in Example 1 of this invention.

[0032] Figure 8 This is a graph showing the test results of the resistance retention rate and moisture absorption capacity retention rate of the self-hygroscopic-conductive synergistic core-shell structure carbon-based composite material prepared in Example 1 of the present invention after multiple cycles.

[0033] Figure 9 This is a scanning electron microscope image of the self-hygroscopic-conductive synergistic core-shell structure carbon-based composite material prepared in Example 2 of this invention.

[0034] Figure 10 This is a diagram of the resistance testing device used in Embodiment 2 of the present invention;

[0035] Figure 11 This is a morphology diagram of the self-hygroscopic-conductive synergistic core-shell structure carbon-based composite material obtained in Example 4 of the present invention;

[0036] Figure 12 This is a morphological diagram of the core-shell structured carbon-based composite material prepared in Comparative Example 4. Detailed Implementation

[0037] Addressing the shortcomings of existing gaseous pollutant purification technologies, such as reliance on external water sources, poor material interface stability, insufficient synergy between hygroscopic, conductive, and active species generation, and low purification efficiency and cycle performance, the inventors of this invention, through long-term research and extensive practice, have proposed the technical solution of this invention. The main focus is on proposing a self-hygroscopic-conductive synergistic core-shell structured carbon-based composite material and its application in the purification of gaseous pollutants mediated by hydrated hydrogen ions, achieving "self-hygroscopic-conductive-H3O" purification. + The synergistic process of "in-situ generation - pollutant oxidation and decomposition" solves the shortcomings of existing technologies, such as dependence on external water sources, poor stability, and low purification efficiency, and provides a new technical path for the efficient purification of gaseous pollutants.

[0038] The following will further explain the technical solution, its implementation process, and its principles. However, it should be understood that within the scope of this invention, the above-mentioned technical features of this invention and the technical features specifically described below (in embodiments) can be combined with each other to form new or preferred technical solutions. Due to space limitations, they will not be described in detail here.

[0039] As one aspect of the technical solution of this invention, a self-hygroscopic-conductive synergistic core-shell structure carbon-based composite material includes: a core layer and a shell layer covering the core layer; wherein, the core layer is a conductive carbon matrix serving as a conductive framework, and the conductive carbon matrix is ​​prepared by multiple gradient carbonization of carbon fiber rods; the shell layer is a hygroscopic coating, comprising a molecular-level composite system of hygroscopic components (hygroscopic organic matter and hygroscopic inorganic salts) formed by hydrogen bonds and coordination bonds, wherein the hygroscopic components have hydrophilic functional groups, and the core layer and the shell layer form a covalently bonded interface through a silane coupling agent. In other words, this self-hygroscopic-conductive synergistic core-shell structure carbon-based composite material has a core-shell structure of a conductive framework and a hygroscopic coating.

[0040] In some embodiments, the conductive carbon matrix is ​​prepared by three-stage gradient carbonization of the original carbon fiber rod.

[0041] In some preferred embodiments, the method for preparing the conductive carbon matrix includes:

[0042] In a protective atmosphere, the original carbon fiber rod is subjected to a first treatment prior to the first temperature to remove internal volatile molecules;

[0043] The carbon fiber rod is heated to a second temperature to perform a second treatment, so that the organic matter on the surface of the carbon fiber rod is carbonized to form an amorphous carbon matrix.

[0044] The carbon fiber rod is heated to a third temperature to perform a third treatment, so that the interface between the carbon fiber rod and the carbonized organic matter is fused and the structure is reconstructed to obtain a conductive carbon matrix.

[0045] The second temperature is greater than the first temperature and less than the third temperature.

[0046] In some preferred embodiments, the protective atmosphere is formed by a protective gas, which includes, but is not limited to, nitrogen.

[0047] In some preferred embodiments, the temperature is raised to a first temperature at a heating rate of 1~5℃ / min, the first temperature being 200~300℃, and the holding time of the first treatment is 1~2h.

[0048] In some preferred embodiments, the temperature is raised to a second temperature of 500-600°C at a heating rate of 1-3°C / min, and the holding time of the second treatment is 2-3 hours.

[0049] In some preferred embodiments, the temperature is raised to a third temperature at a heating rate of 1~2℃ / min, the third temperature being 800~1000℃, and the holding time for the third treatment is 1~2h.

[0050] In some embodiments, the conductive carbon substrate has a diameter of 5-20 μm and a specific surface area of ​​800-1200 m². 2 / g provides good electrical conductivity and structural support for carbon fiber rods.

[0051] In some embodiments, the silane coupling agent includes, but is not limited to, one or more combinations of γ-glycidoxypropyltrimethoxysilane (KH-560), γ-methacryloyloxypropyltrimethoxysilane (KH-570), and γ-methacryloyloxypropyltriethoxysilane (MPTS). The core and shell layers form a covalently bonded interface through the silane coupling agent, improving the adhesion and structural stability of the moisture-absorbing coating.

[0052] In some implementations, the shell is a moisture-absorbing coating composed of moisture-absorbing organic matter and moisture-absorbing inorganic salt at the molecular level. If only moisture-absorbing organic matter is used, the performance will be insufficient; if only moisture-absorbing inorganic salt is used, there is a risk of leakage during the circulation process.

[0053] Furthermore, the thickness of the moisture-absorbing coating is 100~500 nm.

[0054] Furthermore, the hydrophilic functional groups contained in the hygroscopic component may be sulfonic acid groups, ammonium groups, etc., and the hygroscopic organic matter may be one or a combination of two of sulfonate organic matter, ammonium salt organic matter, etc., but is not limited to these.

[0055] Furthermore, the sulfonate organic compounds may include one or more combinations of sodium camphor sulfonate, 2-acrylamido-2-methylpropanesulfonate, sodium dodecyl sulfonate, hexadecyltrimethylammonium p-toluenesulfonate, sodium polystyrene sulfonate, etc., but are not limited thereto.

[0056] Furthermore, the ammonium salt organic compounds include one or more combinations of ammonium acetate, ammonium formate, triammonium citrate, dodecyltrimethylammonium chloride, etc., but are not limited to these.

[0057] In some preferred embodiments, the hygroscopic inorganic salt may include one or more of calcium chloride, magnesium chloride, lithium chloride, etc., but is not limited to these.

[0058] In some preferred embodiments, the mass ratio of the hygroscopic organic matter to the hygroscopic inorganic salt is 1~5:1~3.

[0059] In some embodiments, the content of conductive carbon matrix in the self-hygroscopic-conductive synergistic core-shell carbon-based composite material is 85-90 wt%, the content of silane coupling agent is 1-5 wt%, and the content of hygroscopic component is 5-14 wt%.

[0060] In some embodiments, the carbon-based composite material of the present invention exhibits excellent synergistic properties of self-hygroscopic and electrical conductivity. The core-shell structure design integrates hygroscopic and electrical conductivity functions. At a room temperature of 25°C and a humidity range of 30-90%, the self-hygroscopic rate of the carbon-based composite material with the synergistic core-shell structure is 2.5-9.0 g / (g·h) (the amount of moisture absorbed per gram of carbon-based composite material per hour), and it can generate H3O without an external water source. + It generates and provides sufficient water molecules, which solves the problem of limited application scenarios of existing technologies and can meet the purification needs of low humidity environments such as dry areas in the north.

[0061] In some embodiments, the carbon-based composite material of the present invention exhibits outstanding structural stability and cycling performance. Through molecular-level composite technology and covalent bonding interface design, it avoids the component shedding problem of traditional physical mixed materials. It can cycle through 500 to 1000 times of moisture absorption and desorption, with a moisture absorption rate decay rate of ≤10%, and its cycle service capability far exceeds that of existing technologies.

[0062] In some embodiments, the self-hygroscopic-conductive synergistic core-shell structure carbon-based composite material has a resistivity retention rate of ≥95.5% and a moisture absorption retention rate of ≥91.8%.

[0063] In some embodiments, the self-hygroscopic-conductive synergistic core-shell structured carbon-based composite material H3O + It exhibits high and stable generation efficiency, with a resistance of 0.5~2.0 Ω and a resistivity of 1.0. 10 -4 ~1.0 10 -2 Ω·m, excellent conductivity, H3O after applying voltage + The hygroscopic coating is generated and can stabilize H3O. + Avoid rapid reconciliation.

[0064] Upon application of voltage, the strong electric field on the surface of the self-hygroscopic-conductive synergistic core-shell structure carbon-based composite material of the present invention first induces electrolytic dissociation to generate H⁺. The high-energy electrons generated by partial discharge lower the binding energy barrier between H⁺ and water molecules, promoting the formation of H₃O₂. + It is rapidly generated and remains stable. The sulfonate groups (negatively charged) in the hygroscopic coating interact with H3O through electrostatic attraction. +Combined with stable H3O + When a DC voltage of 220 V is applied, and the initial concentration of volatile organic compounds (VOCs) such as formaldehyde and benzene is 100 mg / m³,... 3 The reaction time is 1 hour, and the reaction chamber volume is 1 m³. 3 Under the condition of using 0.5 g of self-hygroscopic-conductive synergistic core-shell structure carbon-based composite material, its decomposition efficiency for volatile organic compounds is ≥95%, and the purification efficiency of gaseous pollutants is significantly improved.

[0065] As another aspect of the technical solution of this invention, please refer to Figure 1 As shown, the preparation method of a self-hygroscopic-conductive synergistic core-shell structure carbon-based composite material includes: gradient carbonization to regulate the conductive framework, preparation of molecular-level wetting liquid for hygroscopic composite coating, molecular-level wetting composite, interfacial bonding and shaping treatment, etc.

[0066] In some embodiments, the preparation method of the self-hygroscopic-conductive synergistic core-shell structure carbon-based composite material specifically includes:

[0067] The original carbon fiber rods were subjected to multiple gradient carbonization processes to obtain a conductive carbon matrix that serves as a conductive framework.

[0068] A molecular-level hygroscopic wetting liquid comprising a hygroscopic component and a silane coupling agent is provided, wherein the hygroscopic component is capable of forming a molecular-level composite system through hydrogen bonds and coordination bonds, and the hygroscopic component has hydrophilic functional groups;

[0069] The conductive carbon matrix is ​​immersed in the molecular-level hygroscopic wetting liquid for molecular-level wetting and composite. By utilizing capillary action and molecular diffusion effect, the hygroscopic components and silane coupling agent penetrate to the surface of the conductive carbon matrix to achieve molecular-level composite.

[0070] A self-hygroscopic and conductive core-shell structured carbon-based composite material was prepared by interfacial bonding and shaping treatment of a conductive carbon matrix after molecular-level impregnation and composite. A moisture-absorbing coating was formed on the surface of the conductive carbon matrix, and the interfacial covalent bonding between the moisture-absorbing coating and the conductive carbon matrix was achieved through the cross-linking reaction of a silane coupling agent.

[0071] In some preferred embodiments, the structural features and specific preparation methods of the conductive carbon matrix are as described above, and will not be repeated here.

[0072] In some embodiments, the hygroscopic component comprises a molecular-level composite system formed by hygroscopic organic matter and hygroscopic inorganic salt through hydrogen bonds and coordination bonds.

[0073] In some preferred embodiments, the types of silane coupling agent, hygroscopic organic matter, and hygroscopic inorganic salt are as described above and will not be repeated here.

[0074] In some preferred embodiments, the mass ratio of the hygroscopic component to the silane coupling agent is 5~14:1~5.

[0075] In some preferred embodiments, the preparation method specifically includes: mixing hygroscopic organic matter, hygroscopic inorganic salt and water to form a mixed solution with a mass fraction of 10% to 32%, then adding a silane coupling agent, and stirring at 50 to 60°C for 2 to 3 hours to allow the hygroscopic organic matter and inorganic salt to recombine through hydrogen bonds and coordination bonds to obtain a molecular-level hygroscopic wetting solution.

[0076] In some preferred embodiments, the preparation method specifically includes: immersing the conductive carbon matrix in the molecular-level hygroscopic wetting solution, first evacuating to -0.08 to -0.1 MPa and maintaining the pressure for 10 to 20 minutes, then restoring to normal pressure, heating to 40 to 60°C, and maintaining the temperature for 1 to 2 hours to achieve molecular-level composite. This invention forms a uniformly coated shell layer only on the surface of the core layer through molecular-level wetting, without filling the pores inside the carbon fiber rod with hygroscopic components, and a clear covalent bond interface exists between the core layer and the shell layer.

[0077] In some preferred embodiments, the preparation method specifically includes: drying the conductive carbon matrix after molecular-level impregnation and composite at 80~100℃ for 4~6h to preliminarily cure the moisture-absorbing coating; then holding it at 150~200℃ for 1~2h in a protective atmosphere to obtain a self-hygroscopic-conductive synergistic core-shell structure carbon-based composite material.

[0078] In a more specific preferred embodiment of the present invention, the preparation method of a self-hygroscopic-conductive synergistic core-shell structure carbon-based composite material includes the following four key steps:

[0079] (1) Gradient carbonization to regulate the conductive framework: The original carbon fiber rods were placed in a tube furnace, and nitrogen was introduced as a protective gas (flow rate of 50~100 mL / min). Three-stage gradient heating carbonization was adopted:

[0080] First stage: Heat to 200-300℃ at a rate of 1-5℃ / min, hold for 1-2 hours to remove low-volatile molecules inside the carbon fiber rod;

[0081] The second stage involves heating the carbon fiber rod to 500-600℃ at a rate of 1-3℃ / min and holding it at that temperature for 2-3 hours to carbonize the organic matter (such as phenolic resin) on the surface of the carbon fiber rod to form an amorphous carbon matrix.

[0082] The third stage involves heating to 800-1000℃ at a rate of 1-2℃ / min and holding at that temperature for 1-2 hours to achieve interfacial fusion and structural reconstruction between the carbon fiber and the carbonized phenolic resin. After natural cooling to room temperature, a specific surface area of ​​800-1200 m² is obtained. 2 / g conductive framework;

[0083] (2) Preparation of molecular-level wetting solution for hygroscopic coating: Weigh 1-5g of hygroscopic organic matter and 1-3g of hygroscopic inorganic salt, mix them and add them to deionized water to prepare a mixed solution with a mass fraction of 10%-32%; add 1-3 mL of silane coupling agent to the mixed solution and stir at 50-60℃ for 2-3h to allow the hygroscopic organic matter and hygroscopic inorganic salt to undergo molecular-level composite through hydrogen bonds and coordination bonds, and introduce active groups through silane coupling agent to obtain a stable molecular-level hygroscopic wetting solution;

[0084] (3) Molecular-level wetting composite: The conductive skeleton obtained by gradient carbonization is placed in the impregnation equipment, and then the molecular-level hygroscopic wetting liquid prepared in step (2) is injected into the equipment. First, the vacuum is drawn to -0.08~-0.1 MPa and the pressure is maintained for 10~20 min to remove the air in the conductive skeleton. Then, the pressure is restored to normal and the temperature is raised to 40~60℃ and maintained for 1~2 h. By utilizing capillary action and molecular diffusion effect, the molecular-level composite system formed by the hygroscopic components penetrates to the surface of the conductive skeleton to achieve molecular-level coating. The molecular-level composite refers to the uniform dispersion system formed by hygroscopic organic matter and hygroscopic inorganic salt through hydrogen bonds and coordination bonds at the molecular scale.

[0085] (4) Interface bonding and shaping treatment: The conductive carbon matrix after molecular-level impregnation and composite in step (3) is placed in a forced-air drying oven and dried at 80~100℃ for 4~6h to remove moisture and allow the moisture-absorbing coating to be initially cured; then it is placed in a low-temperature tube furnace, nitrogen gas is introduced for protection, and the temperature is raised to 150~200℃ at a rate of 1~2℃ / min and kept at the temperature for 1~2h. The moisture-absorbing coating and the conductive skeleton are covalently bonded at the interface through the crosslinking reaction of the silane coupling agent; after natural cooling, the core-shell structure carbon-based composite material of "conductive skeleton-moisture-absorbing coating" is obtained.

[0086] This invention provides a simple and scalable preparation method that reduces material production costs and expands its application potential in various scenarios such as indoor air purification and industrial waste gas pretreatment.

[0087] As another aspect of the technical solution of the present invention, it also relates to a self-hygroscopic-conductive synergistic core-shell structure carbon-based composite material prepared by the above preparation method.

[0088] As another aspect of the technical solution of the present invention, it also relates to the application of the self-hygroscopic-conductive synergistic core-shell structure carbon-based composite material in the purification of gaseous pollutants mediated by hydrated hydrogen ions.

[0089] Specifically, the hydrated hydrogen ions (H3O) +The purification of gaseous pollutants mediated by this process refers to the in-situ oxidation and decomposition of volatile organic compounds (VOCs) such as formaldehyde and benzene series compounds through the interaction of water molecules adsorbed by the hygroscopic coating with an electric field in a conductive state using a self-hygroscopic-conductive core-shell structure carbon-based composite material. The reaction pathway involves first generating a hydroxymethyl radical intermediate through an electrophilic reaction, then further oxidizing it to formic acid, and finally mineralizing it into carbon dioxide and water.

[0090] Furthermore, the purification mechanism of this invention is as follows: A localized strong electric field is formed in the self-hygroscopic-conductive synergistic core-shell structure carbon-based composite material under a 220V voltage. Water molecules adsorbed by the hygroscopic coating are electrolytically dissociated under the influence of this electric field (H2O→H...). + +OH - H⁺ combines with water molecules to form hydrated hydrogen ions (H₃O₂). + The functional groups in the hygroscopic coating can stabilize H3O + To avoid rapid recombination, it is ultimately controlled by H3O. + Its strong oxidizing properties enable the oxidation, decomposition, and purification of volatile organic compounds (VOCs) such as formaldehyde, breaking them down into harmless substances such as carbon dioxide and water. Ultimately, it achieves an integrated function of self-humidification and air purification, solving the problems of existing materials having single functions, poor humidity adaptability, and low synergistic purification efficiency.

[0091] To more clearly illustrate the objectives, technical solutions, and advantages of this invention, the following detailed description will be provided in conjunction with embodiments. Please note that these embodiments are for illustrative purposes only and are not intended to limit the scope of the invention. Modifications or equivalent substitutions made by those skilled in the art based on their understanding of the technical solutions of this invention are all within the protection scope of this invention.

[0092] In the following specific implementation, the original carbon fiber rods, hygroscopic organic materials, hygroscopic inorganic salts, and silane coupling agents were all purchased from Aladdin Reagent (Shanghai) Co., Ltd. The performance testing standards were uniformly as follows: resistance and resistivity were tested using an electrochemical workstation; hygroscopic performance was tested using a constant temperature and humidity chamber (HS-100) under the following conditions: room temperature 25℃ and corresponding humidity environment.

[0093] Example 1

[0094] (1) Gradient carbonization control of conductive framework: The original carbon fiber rods were placed in a tube furnace and heated to 200℃ at a rate of 1℃ / min and held for 1h. Then, the temperature was increased to 500℃ at a rate of 1℃ / min and held for 2h. Finally, the temperature was increased to 800℃ at a rate of 1℃ / min and held for 1h. After natural cooling, the conductive framework was obtained.

[0095] (2) Preparation of molecular-level hygroscopic wetting solution for hygroscopic composite coating: Weigh 1.0 g of 2-acrylamido-2-methylpropanesulfonate and 1.0 g of lithium chloride, mix them and add them to 18 mL of deionized water to prepare a mixed solution with a mass fraction of 10%; add 1 mL of KH560 to the mixed solution and stir at 50 °C for 2 h to obtain a stable molecular-level hygroscopic wetting solution;

[0096] (3) Molecular-level impregnation and composite of carbon fiber rods: The conductive skeleton obtained by gradient carbonization is placed in the impregnation equipment, and then the molecular-level hygroscopic impregnation liquid is injected into the equipment. First, the vacuum is drawn to -0.08 MPa and the pressure is maintained for 10 min to remove the air in the skeleton. Then, the pressure is restored to normal, the temperature is raised to 40℃, and the temperature is maintained for 1 h to achieve molecular-level coating.

[0097] (4) Interface bonding and shaping treatment: The carbon fiber rods after molecular-level impregnation and composite were placed in a forced-air drying oven and dried at 80°C for 4 hours to remove moisture and allow the moisture-absorbing coating to be initially cured; then they were placed in a low-temperature tube furnace, nitrogen gas was introduced for protection, the temperature was raised to 150°C at a rate of 2°C / min, and kept at the temperature for 1 hour. After natural cooling, carbon fiber rods with a conductive skeleton-moisture-absorbing coating core-shell structure were obtained, namely, self-moisture-conductive synergistic core-shell structure carbon-based composite material.

[0098] Figure 2A , Figure 2B These are scanning electron microscope (SEM) images and magnified views of the original carbon fiber rods used in this embodiment. Figure 3 These are macroscopic photographs of the original carbon fiber rods. Figure 4A , Figure 4B These are scanning electron microscope (SEM) images and magnified views of the carbon fiber rods after gradient carbonization. Figure 5 These are macroscopic morphological photographs of carbon fiber rods after gradient carbonization. Figure 6A , Figure 6B The images are scanning electron microscope (SEM) images and magnified images of the self-hygroscopic-conductive synergistic core-shell carbon-based composite material obtained after molecular-level impregnation, interfacial bonding, and shaping treatment. They clearly show that the product has a core-shell structure, with the core carbon fiber rods and the shell hygroscopic coating tightly bonded together without obvious detachment. Figure 7 These are macroscopic photographs of its morphology. Characterization tests show that the diameter of the core layer is 5–20 μm, and the specific surface area is 800 m². 2 / g, with a shell thickness of approximately 100 nm.

[0099] Figure 8This figure shows the results of resistance retention and moisture absorption retention tests (at 30% humidity) of the self-hygroscopic-conductive synergistic core-shell carbon-based composite material prepared in this embodiment after multiple cycles. Tests showed that the self-hygroscopic rates of this composite material were 3.2 g / (g·h), 4.8 g / (g·h), and 6.5 g / (g·h) at humidity levels of 30%, 60%, and 90%, respectively; the resistance of this composite material was 2.0 Ω, and the resistivity was 1.0 Ω. 10 -2 Ω·m; can be cycled 500 times, moisture absorption rate decay rate is 8.2% at 30% humidity, and resistance decay rate is 4.5%.

[0100] When a voltage of 220 V is applied, the initial formaldehyde concentration is 100 mg / m³. 3 Under the conditions of a reaction time of 1 hour, a reaction chamber volume of 1 m³, and a carbon fiber rod dosage of 0.5 g, the carbon fiber rod has a formaldehyde decomposition efficiency of 92.7%.

[0101] Example 2

[0102] (1) Gradient carbonization regulation of conductive framework: The original carbon fiber rods were placed in a tube furnace and heated to 200°C at a rate of 5°C / min and held for 1 hour. Then, the temperature was increased to 500°C at a rate of 3°C / min and held for 2 hours. Finally, the temperature was increased to 800°C at a rate of 2°C / min and held for 1 hour. After natural cooling, the conductive framework was obtained.

[0103] (2) Preparation of molecular-level hygroscopic wetting solution for hygroscopic composite coating: Weigh 5.0g of sodium camphor sulfonate and 1.0g of calcium chloride, mix them and add them to 18 mL of deionized water to prepare a mixed solution with a mass fraction of 25%; add 1 mL of KH560 to the mixed solution and stir at 50℃ for 2h to obtain a stable molecular-level hygroscopic wetting solution.

[0104] (3) Molecular-level impregnation and composite of carbon fiber rods: The conductive skeleton obtained by gradient carbonization is placed in the impregnation equipment, and then the molecular-level hygroscopic impregnation liquid is injected into the equipment. First, the vacuum is drawn to -0.08 MPa and the pressure is maintained for 10 min to remove the air in the skeleton. Then, the pressure is restored to normal, the temperature is raised to 40℃, and the temperature is maintained for 1 h to achieve molecular-level coating.

[0105] (4) Interface bonding and shaping treatment: The molecularly impregnated carbon fiber rods were placed in a forced-air drying oven and dried at 80℃ for 4 hours to remove moisture and allow the moisture-absorbing coating to initially cure; then they were placed in a low-temperature tube furnace, protected with nitrogen, and heated to 150℃ at a rate of 2℃ / min, held for 1 hour, and naturally cooled to obtain carbon fiber rods with a conductive skeleton-moisture-absorbing coating core-shell structure, i.e., a self-moisture-absorbing-conductive synergistic core-shell structure carbon-based composite material. Its scanning electron microscope morphology is shown in the figure below. Figure 9 As shown, the diameter of the core layer is 5~20μm, and the specific surface area is 900m². 2 / g, with a shell thickness of approximately 200 nm.

[0106] Tests showed that the self-hygroscopic and conductive synergistic core-shell carbon-based composite material exhibited self-hygroscopic rates of 4.5 g / (g·h), 5.8 g / (g·h), and 7.0 g / (g·h) at humidity levels of 30%, 60%, and 90%, respectively; the resistivity of the composite material was 1.4 Ω (resistance testing equipment such as...). Figure 10 As shown), the resistivity is 1.0. 10 -3 Ω·m; can be cycled 600 times, moisture absorption rate decay rate is 8.0% at 30% humidity, and resistance decay rate is 4.2%.

[0107] When a voltage of 220 V is applied, the initial concentration of benzene is 100 mg / m³. 3 The reaction time is 1 hour, and the reaction chamber volume is 1 cubic meter. 3 Under the condition that the carbon fiber rod dosage is 0.5 g, the decomposition efficiency of the carbon fiber rod for benzene is 93.5%.

[0108] Example 3

[0109] (1) Gradient carbonization control of conductive framework: The original carbon fiber rods were placed in a tube furnace and heated to 200℃ at a rate of 3℃ / min and held for 1h. Then, the temperature was increased to 500℃ at a rate of 2℃ / min and held for 2h. Finally, the temperature was increased to 800℃ at a rate of 2℃ / min and held for 1h. After natural cooling, the conductive framework was obtained.

[0110] (2) Preparation of molecular-level hygroscopic wetting solution for hygroscopic composite coating: Weigh 5.0g of sodium dodecyl sulfonate and 3.0g of magnesium chloride, mix them and add them to 17mL of deionized water to prepare a mixed solution with a mass fraction of 32.0%; add 1 mL of MPTS to the mixed solution and stir at 50℃ for 2h to obtain a stable molecular-level hygroscopic wetting solution.

[0111] (3) Molecular-level impregnation and composite of carbon fiber rods: The conductive skeleton obtained by gradient carbonization is placed in an impregnation device, and then the molecular-level hygroscopic impregnation liquid is injected into the device. First, the vacuum is drawn to -0.1 MPa and the pressure is maintained for 20 min to remove the air in the skeleton. Then, the pressure is restored to normal and the temperature is raised to 40℃ and maintained for 1 h. By utilizing capillary action and molecular diffusion effect, the hygroscopic composite component penetrates to the surface of the conductive skeleton to achieve molecular-level coating.

[0112] (4) Interface bonding and shaping treatment: The carbon fiber rods after molecular-level impregnation and composite were placed in a forced-air drying oven and dried at 80℃ for 4h to remove moisture and allow the moisture-absorbing coating to be initially cured; then they were placed in a low-temperature tube furnace, nitrogen gas was introduced for protection, and the temperature was raised to 150℃ at a rate of 2℃ / min and held for 1h. The moisture-absorbing coating and the conductive skeleton were covalently bonded at the interface through the crosslinking reaction of the silane coupling agent; after natural cooling, carbon fiber rods with a conductive skeleton-moisture-absorbing coating core-shell structure were obtained, namely, carbon-based composite material with self-moisture-absorbing-conductive synergistic core-shell structure, with a core diameter of 5~20μm, a specific surface area of ​​1000m² / g, and a shell thickness of about 500 nm.

[0113] Tests showed that the self-absorbing moisture rates of this self-hygroscopic-conductive synergistic core-shell carbon-based composite material were 5.9 g / (g·h), 7.1 g / (g·h), and 8.8 g / (g·h) at humidity levels of 30%, 60%, and 90%, respectively; the electrical resistance of this self-hygroscopic-conductive synergistic core-shell carbon-based composite material was 0.5 Ω, and its resistivity was 1.0 Ω. 10 -4 Ω·m; can be cycled 800 times, moisture absorption rate decay rate is 6.5% at 30% humidity, and resistance decay rate is 4.0%.

[0114] When a voltage of 220 V is applied, the initial formaldehyde concentration is 100 mg / m³. 3 The reaction time is 1 hour, and the reaction chamber volume is 1 cubic meter. 3 Under the condition that the carbon fiber rod dosage is 0.5 g, the carbon fiber rod decomposition efficiency of formaldehyde is 94.7%.

[0115] Example 4

[0116] (1) Gradient carbonization regulation of conductive framework: The original carbon fiber rods were placed in a tube furnace and heated to 200°C at a rate of 5°C / min and held for 1 hour. Then, the temperature was increased to 500°C at a rate of 3°C / min and held for 2 hours. Finally, the temperature was increased to 800°C at a rate of 2°C / min and held for 1 hour. After natural cooling, the conductive framework was obtained.

[0117] (2) Preparation of molecular-level hygroscopic wetting solution for hygroscopic composite coating: Weigh 5.0g of dodecyltrimethylammonium chloride and 3.0g of lithium chloride, mix them and add them to 17 mL of deionized water to prepare a mixed solution with a mass fraction of 32.0%; add 5 mL of KH570 to the mixed solution and stir at 50℃ for 2h to obtain a stable molecular-level hygroscopic wetting solution;

[0118] (3) Molecular-level impregnation and composite of carbon fiber rods: The conductive skeleton obtained by gradient carbonization is placed in an impregnation device, and then the molecular-level hygroscopic impregnation liquid is injected into the device. First, the vacuum is drawn to -0.1 MPa and the pressure is maintained for 20 min to remove the air in the skeleton. Then, the pressure is restored to normal and the temperature is raised to 40℃ and maintained for 1 h. By utilizing capillary action and molecular diffusion effect, the hygroscopic composite component penetrates to the surface of the conductive skeleton to achieve molecular-level coating.

[0119] (4) Interface bonding and shaping treatment: The molecularly impregnated carbon fiber rods were placed in a forced-air drying oven and dried at 80℃ for 4 hours to remove moisture and allow the moisture-absorbing coating to initially cure; then they were placed in a low-temperature tube furnace, protected by nitrogen, and heated to 150℃ at a rate of 2℃ / min, held for 1 hour, and naturally cooled to obtain carbon fiber rods with a conductive skeleton-moisture-absorbing coating core-shell structure, i.e., a self-moisture-absorbing-conductive synergistic core-shell structure carbon-based composite material, the morphology of which is shown in the figure. Figure 11 As shown, the interfacial bonding state between the core carbon fiber and the shell composite component can be observed using high-magnification scanning electron microscopy, proving the molecular-level coating effect. The core layer has a diameter of 5–20 μm and a specific surface area of ​​1000 m². 2 / g, with a shell thickness of approximately 490 nm.

[0120] Tests showed that the self-absorbing moisture rates of this self-hygroscopic-conductive synergistic core-shell carbon-based composite material were 6.0 g / (g·h), 7.5 g / (g·h), and 8.9 g / (g·h) at humidity levels of 30%, 60%, and 90%, respectively; the electrical resistance of this self-hygroscopic-conductive synergistic core-shell carbon-based composite material was 0.8 Ω, and its resistivity was 0.8 Ω. 10 -3 Ω·m; can be cycled 900 times, moisture absorption rate decay rate is 5.5% at 30% humidity, and resistance decay rate is 3.7%.

[0121] When a voltage of 220 V is applied, the initial concentration of toluene is 100 mg / m³. 3 Under the conditions of a reaction time of 1 hour, a reaction chamber volume of 1 m³, and a carbon fiber rod dosage of 0.5 g, the decomposition efficiency of carbon fiber rods for toluene was 94.9%.

[0122] Example 5

[0123] (1) Gradient carbonization regulation of conductive framework: The original carbon fiber rods were placed in a tube furnace and heated to 300°C at a rate of 5°C / min and held for 2 hours to remove low molecular weight volatile molecules in the phenolic resin. Then, the temperature was increased to 600°C at a rate of 3°C / min and held for 3 hours to carbonize the phenolic resin and form an amorphous carbon matrix. Finally, the temperature was increased to 1000°C at a rate of 2°C / min and held for 2 hours to achieve interfacial fusion and structural reconstruction of carbon fiber and carbonized phenolic resin. After natural cooling, the conductive framework was obtained.

[0124] (2) Preparation of molecular-level hygroscopic wetting solution for hygroscopic composite coating: Weigh 5.0g of sodium polystyrene sulfonate and 3.0g of lithium chloride, mix them and add them to 17mL of deionized water to prepare a mixed solution with a mass fraction of 32%; add 1mL of KH560 to the mixed solution and stir at 50℃ for 2h to allow the hygroscopic organic matter and inorganic salt to undergo molecular-level composite through hydrogen bonds and coordination bonds, and introduce active groups through silane coupling agent to obtain a stable molecular-level hygroscopic wetting solution;

[0125] (3) Molecular-level impregnation and composite of carbon fiber rods: The conductive skeleton obtained by gradient carbonization is placed in an impregnation device, and then the molecular-level hygroscopic impregnation liquid is injected into the device. First, the vacuum is drawn to -0.1 MPa and the pressure is maintained for 20 min to remove the air in the skeleton. Then, the pressure is restored to normal and the temperature is raised to 40℃ and maintained for 1 h. By utilizing capillary action and molecular diffusion effect, the hygroscopic composite component penetrates to the surface of the conductive skeleton to achieve molecular-level coating.

[0126] (4) Interface bonding and shaping treatment: The carbon fiber rods after molecular-level impregnation and composite were placed in a forced-air drying oven and dried at 80℃ for 4h to remove moisture and allow the moisture-absorbing coating to be initially cured; then they were placed in a low-temperature tube furnace, nitrogen gas was introduced for protection, and the temperature was raised to 150℃ at a rate of 2℃ / min and kept at 1h. The moisture-absorbing coating and the conductive skeleton were covalently bonded at the interface through the cross-linking reaction of the silane coupling agent. After natural cooling, carbon fiber rods with a conductive skeleton-moisture-absorbing coating core-shell structure were obtained, namely, carbon-based composite material with self-moisture-conductive synergistic core-shell structure. The diameter of the core layer is 5~20μm, the specific surface area is 1200m² / g, and the thickness of the shell layer is about 500 nm.

[0127] Tests showed that the self-absorbing moisture rates of this self-hygroscopic-conductive synergistic core-shell carbon-based composite material were 6.1 g / (g·h), 8.0 g / (g·h), and 9.0 g / (g·h) at humidity levels of 30%, 60%, and 90%, respectively; the electrical resistance of this self-hygroscopic-conductive synergistic core-shell carbon-based composite material was 0.6 Ω, and its resistivity was 0.8 Ω. 10 -3 Ω·m; can be cycled 1000 times, moisture absorption rate decay rate is 4.5%, and resistance decay rate is 3.5%.

[0128] When a voltage of 220 V is applied, the initial formaldehyde concentration is 100 mg / m³. 3 Under the conditions of a reaction time of 1 hour, a reaction chamber volume of 1 m³, and a carbon fiber rod dosage of 0.5 g, the carbon fiber rod has a formaldehyde decomposition efficiency of 95.7%.

[0129] Example 6

[0130] (1) Gradient carbonization regulation of conductive framework: The original carbon fiber rods were placed in a tube furnace and heated to 300°C at a rate of 5°C / min and held for 2 hours to remove low molecular weight volatile molecules in the phenolic resin. Then, the temperature was increased to 600°C at a rate of 3°C / min and held for 3 hours to carbonize the phenolic resin and form an amorphous carbon matrix. Finally, the temperature was increased to 1000°C at a rate of 2°C / min and held for 2 hours to achieve interfacial fusion and structural reconstruction of carbon fiber and carbonized phenolic resin. After natural cooling, the conductive framework was obtained.

[0131] (2) Preparation of molecular-level hygroscopic wetting solution for hygroscopic composite coating: Weigh 5.0g of triammonium citrate and 3.0g of lithium chloride, mix them and add them to 17mL of deionized water to prepare a mixed solution with a mass fraction of 32%; add 1mL of MPTS to the mixed solution and stir at 50℃ for 2h to allow the hygroscopic organic matter and inorganic salt to undergo molecular-level composite through hydrogen bonds and coordination bonds, and introduce active groups through silane coupling agent to obtain a stable molecular-level hygroscopic wetting solution;

[0132] (3) Molecular-level impregnation and composite of carbon fiber rods: The conductive skeleton obtained by gradient carbonization is placed in an impregnation device, and then the molecular-level hygroscopic impregnation liquid is injected into the device. First, the vacuum is drawn to -0.1 MPa and the pressure is maintained for 20 min to remove the air in the skeleton. Then, the pressure is restored to normal and the temperature is raised to 60℃ and maintained for 2 h. By utilizing capillary action and molecular diffusion effect, the hygroscopic composite component penetrates to the surface of the conductive skeleton to achieve molecular-level coating.

[0133] (4) Interface bonding and shaping treatment: The carbon fiber rods after molecular-level impregnation and composite were placed in a forced-air drying oven and dried at 100℃ for 4 hours to remove moisture and allow the moisture-absorbing coating to initially cure; then they were placed in a low-temperature tube furnace, protected by nitrogen, and heated to 200℃ at a rate of 2℃ / min and held for 2 hours. The moisture-absorbing coating and the conductive skeleton were covalently bonded at the interface through the crosslinking reaction of the silane coupling agent. After natural cooling, carbon fiber rods with a conductive skeleton-moisture-absorbing coating core-shell structure were obtained, namely, a carbon-based composite material with a self-moisture-absorbing-conductive synergistic core-shell structure. The diameter of the core layer was 5~20μm and the specific surface area was 1100m². 2 / g, with a shell thickness of approximately 490 nm.

[0134] Tests showed that the self-absorbing moisture rates of this self-hygroscopic-conductive synergistic core-shell carbon-based composite material were 6.0 g / (g·h), 7.9 g / (g·h), and 9.0 g / (g·h) at humidity levels of 30%, 60%, and 90%, respectively; the electrical resistance of this self-hygroscopic-conductive synergistic core-shell carbon-based composite material was 0.5 Ω, and its resistivity was 0.7 Ω. 10 -3 Ω·m; can be cycled 1000 times, moisture absorption rate decay rate is 4.4%, and resistance decay rate is 3.7%.

[0135] When a voltage of 220 V is applied, the initial formaldehyde concentration is 100 mg / m³. 3 The reaction time is 1 hour, and the reaction chamber volume is 1 cubic meter. 3 Under the condition that the carbon fiber rod dosage is 0.5 g, the carbon fiber rod decomposition efficiency of formaldehyde is 95.9%.

[0136] Comparative Example 1: Crosslinking with a silane coupling agent lacking crosslinking

[0137] (1) Gradient carbonization regulation of conductive framework: The original carbon fiber rods were placed in a tube furnace and heated to 300℃ at a rate of 5℃ / min and held for 2h. Then, the temperature was increased to 600℃ at a rate of 3℃ / min and held for 3h. Finally, the temperature was increased to 1000℃ at a rate of 2℃ / min and held for 2h. After natural cooling, the conductive framework was obtained.

[0138] (2) Preparation of the hygroscopic wetting solution for the hygroscopic composite coating: Weigh 5.0g sodium dodecyl sulfonate and 3.0g lithium chloride, mix them and add them to 17 mL of deionized water to prepare a mixed solution with a mass fraction of 32%;

[0139] (3) Molecular-level impregnation and composite of carbon fiber rods: The conductive skeleton obtained by gradient carbonization is placed in an impregnation device, and then the hygroscopic impregnation liquid is injected into the device. First, the vacuum is drawn to -0.1 MPa and held for 10 min, then the temperature is raised to 40℃ and held for 1 h.

[0140] (4) Shaping treatment: The impregnated carbon fiber rods are placed in a forced-air drying oven and dried at 80℃ for 4h to remove moisture and allow the moisture-absorbing coating to be initially cured. Then, they are placed in a low-temperature tube furnace, protected by nitrogen, and heated to 150℃ at a rate of 2℃ / min and kept at that temperature for 1h. After natural cooling, carbon fiber rods with a conductive skeleton-moisture-absorbing coating core-shell structure are obtained. The diameter of the core layer is 5~20μm, the specific surface area is 800m² / g, and the thickness of the shell layer is about 480 nm.

[0141] Tests showed that the self-hygroscopic absorption rates of the carbon fiber rod with the conductive skeleton-hygroscopic coating core-shell structure were 4.5 g / (g·h), 6.0 g / (g·h), and 7.1 g / (g·h), respectively, at humidity levels of 30%, 60%, and 90%. The resistance of the carbon fiber rod with the conductive skeleton-hygroscopic coating core-shell structure was 2.8 Ω, and its resistivity was 0.9 Ω. 10 -1 Ω·m; can be cycled 100 times, moisture absorption rate decay rate is 20.5%, and resistance decay rate is 30.5%.

[0142] When a voltage of 220 V is applied, the initial concentration of toluene is 100 mg / m³. 3 The reaction time is 1 hour, and the reaction chamber volume is 1 cubic meter. 3 Under the condition of using 0.5 g of carbon fiber rods, the decomposition efficiency of carbon fiber rods for toluene is 89.2%, which still has a certain purification effect, but the cycle performance is significantly reduced. This is because the cross-linking of silane coupling agent is missing. It can be demonstrated that the covalent bonding interface formed by silane coupling agent can significantly improve the structural stability and the synergistic properties of conductivity and moisture absorption.

[0143] Comparative Example 2: Carbon rod fibers that have not undergone gradient carbonization (dried but not carbonized)

[0144] (1) Preparation of molecular-level hygroscopic wetting solution for hygroscopic composite coating: Weigh 5.0g sodium dodecyl sulfonate and 3.0g lithium chloride, mix them and add them to 17 mL of deionized water to prepare a mixed solution with a mass fraction of 32%; add 1 mL of KH560 to the mixed solution and stir at 50℃ for 2h to obtain a stable molecular-level hygroscopic wetting solution.

[0145] (2) Molecular-level impregnation and composite of carbon fiber rods: Place the original carbon rod fibers that have not undergone gradient carbonization in the impregnation equipment, and then inject the molecular-level hygroscopic impregnation liquid into the equipment. First, evacuate to -0.1 MPa and hold the pressure for 10 min, then raise the temperature to 40℃ and hold for 1 h.

[0146] (3) Interface bonding and shaping treatment: The impregnated carbon fiber rods were placed in a forced-air drying oven and dried at 80℃ for 4 hours to remove moisture and allow the moisture-absorbing coating to initially cure. Then, they were placed in a low-temperature tube furnace, protected by nitrogen, and heated to 150℃ at a rate of 2℃ / min and held for 1 hour. After natural cooling, core-shell structured carbon fiber rods were obtained, with a core layer diameter of 5~20μm and a specific surface area of ​​400m². 2 / g, with a shell thickness of approximately 400 nm.

[0147] The composite material prepared in this comparative example, which has not undergone gradient carbonization, can be tested for moisture absorption rate normally. However, due to the lack of a conductive framework, a strong electric field cannot be formed, leading to H3O... +Since it cannot be generated, VOCs decomposition experiments cannot be carried out.

[0148] Comparative Example 3: Gradient carbonization control temperature was too high

[0149] (1) Gradient carbonization regulation of conductive framework: The original carbon fiber rods were placed in a tube furnace and heated to 500℃ at a rate of 5℃ / min and held for 1h. Then, the temperature was increased to 900℃ at a rate of 3℃ / min and held for 2h. Finally, the temperature was increased to 1200℃ at a rate of 2℃ / min and held for 1h. After natural cooling, the conductive framework was obtained.

[0150] (2) Preparation of molecular-level hygroscopic wetting solution for hygroscopic composite coating: Weigh 5.0g sodium dodecyl sulfonate and 3.0g lithium chloride, mix them and add them to 17 mL of deionized water to prepare a mixed solution with a mass fraction of 32%; add 1 mL of KH560 to the mixed solution and stir at 50℃ for 2h to obtain a stable molecular-level hygroscopic wetting solution;

[0151] (3) Molecular-level impregnation and composite of carbon fiber rods: The conductive skeleton obtained by gradient carbonization is placed in the impregnation equipment, and then the hygroscopic impregnation liquid is injected into the equipment. First, the vacuum is drawn to -0.08 MPa and held for 10 min, then the temperature is raised to 40℃ and held for 1 h.

[0152] (4) Interface bonding and shaping treatment: The impregnated carbon fiber rods are placed in a forced-air drying oven and dried at 80°C for 4 hours to remove moisture and allow the moisture-absorbing coating to be initially cured. Then, they are placed in a low-temperature tube furnace, protected by nitrogen, and heated to 150°C at a rate of 2°C / min and kept at that temperature for 1 hour. After natural cooling, carbon fiber rods with a conductive skeleton-moisture-absorbing coating core-shell structure are obtained.

[0153] The carbon fiber rods in this comparative example became brittle and powdered at high temperatures, making it impossible to conduct moisture absorption and formaldehyde removal tests. This demonstrates that the temperature for gradient carbonization must be strictly controlled within the range of 800~1000℃, as excessively high temperatures will damage the structural integrity of the carbon rods.

[0154] Comparative Example 4: Excessive content of hygroscopic components

[0155] (1) Gradient carbonization regulation of conductive framework: The original carbon fiber rods were placed in a tube furnace and heated to 200°C at a rate of 5°C / min and held for 1 hour. Then, the temperature was increased to 500°C at a rate of 3°C / min and held for 2 hours. Finally, the temperature was increased to 800°C at a rate of 2°C / min and held for 1 hour. After natural cooling, the conductive framework was obtained.

[0156] (2) Preparation of molecular-level hygroscopic wetting solution for hygroscopic composite coating: Weigh 10.0g sodium dodecyl sulfonate and 3.0g lithium chloride, mix them and add them to 19.5mL deionized water to prepare a mixed solution with a mass fraction of 40.0%; add 1 mL KH560 to the mixed solution and stir at 50℃ for 2h to obtain a stable molecular-level hygroscopic wetting solution;

[0157] (3) Molecular-level impregnation and composite of carbon fiber rods: The conductive skeleton obtained by gradient carbonization is placed in the impregnation equipment, and then the hygroscopic impregnation liquid is injected into the equipment. First, the vacuum is drawn to -0.1 MPa and pressure is maintained for 20 min. Then, the temperature is raised to 40℃ and kept for 1 h. By utilizing capillary action and molecular diffusion effect, the hygroscopic composite component penetrates to the surface of the skeleton to achieve molecular-level coating.

[0158] (4) Interface bonding and shaping treatment: The impregnated carbon fiber rods were placed in a forced-air drying oven and dried at 80℃ for 4 hours to remove moisture and allow the moisture-absorbing coating to initially cure. Then, they were placed in a low-temperature tube furnace and protected with nitrogen. The temperature was increased to 150℃ at a rate of 2℃ / min and held for 1 hour. The interface covalent bonding between the moisture-absorbing coating and the conductive skeleton was achieved through the crosslinking reaction of the silane coupling agent. After natural cooling, carbon fiber rods with a core-shell structure of conductive skeleton-moisture-absorbing coating were obtained. The diameter of the core layer was 5~20μm and the specific surface area was 500m². 2 / g, the shell thickness is about 600 nm. According to Figure 12 Scanning electron microscopy images show that the conductive framework is filled with an excessive amount of hygroscopic components.

[0159] Excessive moisture-absorbing components covering conductive sites cause a sharp increase in resistivity and block moisture transport channels, resulting in a significant decrease in both self-hygroscopic rate and conductivity. Tests showed that the self-hygroscopic rates of the carbon fiber rods prepared in this comparative example were 1.2 g / (g·h), 2.2 g / (g·h), and 3.0 g / (g·h) at humidity levels of 30%, 60%, and 90%, respectively, with a resistance of 3.0 Ω and a resistivity of 1.0 Ω. 10 -1 Ω·m cannot be cyclic.

[0160] When a voltage of 220 V is applied, the initial formaldehyde concentration is 100 mg / m³. 3 Under the conditions of a reaction time of 1 hour, a reaction chamber volume of 1 m³, and a carbon fiber rod dosage of 0.5 g, the carbon fiber rod decomposition efficiency of formaldehyde was 49.2%. This proves that the amount of moisture-absorbing component needs to be controlled within the range specified in this invention. Excessive dosage will cause the moisture-absorbing component to leak and fall off, destroying the moisture absorption-conductivity synergistic effect.

[0161] Comparative Example 5

[0162] This comparative example uses only hygroscopic organic matter, specifically including:

[0163] (1) Gradient carbonization regulation of conductive framework: The original carbon fiber rods were placed in a tube furnace and heated to 300°C at a rate of 5°C / min and held for 2 hours to remove low molecular weight volatile molecules in the phenolic resin. Then, the temperature was increased to 600°C at a rate of 3°C / min and held for 3 hours to carbonize the phenolic resin and form an amorphous carbon matrix. Finally, the temperature was increased to 1000°C at a rate of 2°C / min and held for 2 hours to achieve interfacial fusion and structural reconstruction of carbon fiber and carbonized phenolic resin. After natural cooling, the conductive framework was obtained.

[0164] (2) Preparation of molecular-level hygroscopic wetting solution for hygroscopic composite coating: Weigh 8.0g of sodium polystyrene sulfonate, mix and add to 17mL of deionized water to prepare a mixed solution with a mass fraction of 32%; add 1mL of KH560 to the mixed solution and stir at 50℃ for 2h to allow the hygroscopic organic matter and inorganic salt to undergo molecular-level composite through hydrogen bonds and coordination bonds, and introduce active groups through silane coupling agent to obtain a stable molecular-level hygroscopic wetting solution;

[0165] (3) Molecular-level impregnation and composite of carbon fiber rods: The conductive skeleton obtained by gradient carbonization is placed in an impregnation device, and then the molecular-level hygroscopic impregnation liquid is injected into the device. First, the vacuum is drawn to -0.1 MPa and the pressure is maintained for 20 min to remove the air in the skeleton. Then, the pressure is restored to normal and the temperature is raised to 40℃ and maintained for 1 h. By utilizing capillary action and molecular diffusion effect, the hygroscopic composite component penetrates to the surface of the conductive skeleton to achieve molecular-level coating.

[0166] (4) Interface bonding and shaping treatment: The carbon fiber rods after molecular-level impregnation and composite were placed in a forced-air drying oven and dried at 80℃ for 4h to remove moisture and allow the moisture-absorbing coating to be initially cured; then they were placed in a low-temperature tube furnace, nitrogen gas was introduced for protection, and the temperature was raised to 150℃ at a rate of 2℃ / min and kept at the temperature for 1h. The moisture-absorbing coating and the conductive skeleton were covalently bonded at the interface through the cross-linking reaction of the silane coupling agent. After natural cooling, carbon fiber rods with a conductive skeleton-moisture-absorbing coating core-shell structure were obtained, namely, self-moisture-conductive synergistic core-shell structure carbon-based composite material. The diameter of the core layer is 5~18μm, the specific surface area is 1000m² / g, and the thickness of the shell layer is about 480 nm.

[0167] Tests showed that the self-absorbing moisture rates of this self-hygroscopic-conductive synergistic core-shell carbon-based composite material were 1.5 g / (g·h), 2.7 g / (g·h), and 3.2 g / (g·h) at humidity levels of 30%, 60%, and 90%, respectively; the electrical resistance of this self-hygroscopic-conductive synergistic core-shell carbon-based composite material was 1.0 Ω, and its resistivity was 1.0 Ω. 10 -3Ω·m; can be cycled 500 times, moisture absorption rate decay rate is 9.2%, and resistance decay rate is 3.7%.

[0168] When a voltage of 220 V is applied, the initial formaldehyde concentration is 100 mg / m³, the reaction time is 1 h, and the reaction chamber volume is 1 m³. 3 When the carbon fiber rod dosage is 0.5 g, the carbon fiber rod decomposition efficiency for formaldehyde is 81.2%. This is because only hygroscopic organic matter is used, resulting in insufficient decomposition performance.

[0169] Comparative Example 6

[0170] This comparative example uses only hygroscopic inorganic salts, specifically including:

[0171] (1) Gradient carbonization regulation of conductive framework: The original carbon fiber rods were placed in a tube furnace and heated to 300°C at a rate of 5°C / min and held for 2 hours to remove low molecular weight volatile molecules in the phenolic resin. Then, the temperature was increased to 600°C at a rate of 3°C / min and held for 3 hours to carbonize the phenolic resin and form an amorphous carbon matrix. Finally, the temperature was increased to 1000°C at a rate of 2°C / min and held for 2 hours to achieve interfacial fusion and structural reconstruction of carbon fiber and carbonized phenolic resin. After natural cooling, the conductive framework was obtained.

[0172] (2) Preparation of molecular-level hygroscopic wetting solution for hygroscopic composite coating: Weigh 8.0g of lithium chloride, mix and add to 17mL of deionized water to prepare a mixed solution with a mass fraction of 32%; add 1mL of KH560 to the mixed solution and stir at 50℃ for 2h to allow the hygroscopic organic matter and inorganic salt to undergo molecular-level composite through hydrogen bonds and coordination bonds, and introduce active groups through silane coupling agent to obtain a stable molecular-level hygroscopic wetting solution;

[0173] (3) Molecular-level impregnation and composite of carbon fiber rods: The conductive skeleton obtained by gradient carbonization is placed in an impregnation device, and then the molecular-level hygroscopic impregnation liquid is injected into the device. First, the vacuum is drawn to -0.1 MPa and the pressure is maintained for 20 min to remove the air in the skeleton. Then, the pressure is restored to normal and the temperature is raised to 40℃ and maintained for 1 h. By utilizing capillary action and molecular diffusion effect, the hygroscopic composite component penetrates to the surface of the conductive skeleton to achieve molecular-level coating.

[0174] (4) Interface bonding and shaping treatment: The carbon fiber rods after molecular-level impregnation and composite were placed in a forced-air drying oven and dried at 80℃ for 4 hours to remove moisture and allow the moisture-absorbing coating to initially cure; then they were placed in a low-temperature tube furnace, protected by nitrogen, and heated to 150℃ at a rate of 2℃ / min and held for 1 hour. The moisture-absorbing coating and the conductive skeleton were covalently bonded at the interface through the crosslinking reaction of the silane coupling agent. After natural cooling, carbon fiber rods with a conductive skeleton-moisture-absorbing coating core-shell structure were obtained, namely, a carbon-based composite material with a self-moisture-absorbing-conductive synergistic core-shell structure. The diameter of the core layer was 5~20μm and the specific surface area was 900m². 2 / g, with a shell thickness of approximately 470 nm.

[0175] Tests showed that the self-absorbing moisture rates of this self-hygroscopic-conductive synergistic core-shell carbon-based composite material were 2.4 g / (g·h), 3.5 g / (g·h), and 4.6 g / (g·h) at humidity levels of 30%, 60%, and 90%, respectively; the resistivity of this self-hygroscopic-conductive synergistic core-shell carbon-based composite material was 0.9 Ω. 10 -3 Ω·m; cannot be cycled.

[0176] When a voltage of 220 V is applied, the initial formaldehyde concentration is 100 mg / m³. 3 The reaction time is 1 hour, and the reaction chamber volume is 1 cubic meter. 3 When the amount of carbon fiber rod is 0.5 g, the single-pass decomposition efficiency of the carbon fiber rod for formaldehyde is 78.7%, which means it cannot be recycled and there is a risk of leakage during the recycling process.

[0177] Comparative Example 7

[0178] This comparative example uses only ordinary impregnation, specifically including:

[0179] (1) Gradient carbonization regulation of conductive framework: The original carbon fiber rods were placed in a tube furnace and heated to 300°C at a rate of 5°C / min and held for 2 hours to remove low molecular weight volatile molecules in the phenolic resin. Then, the temperature was increased to 600°C at a rate of 3°C / min and held for 3 hours to carbonize the phenolic resin and form an amorphous carbon matrix. Finally, the temperature was increased to 1000°C at a rate of 2°C / min and held for 2 hours to achieve interfacial fusion and structural reconstruction of carbon fiber and carbonized phenolic resin. After natural cooling, the conductive framework was obtained.

[0180] (2) Preparation of hygroscopic wetting solution for hygroscopic composite coating: Weigh 5.0g of sodium polystyrene sulfonate and 3.0g of lithium chloride, mix them and add them to 17mL of deionized water to prepare a mixed solution with a mass fraction of 32%; add 1mL of KH560 to the mixed solution and stir at 50℃ for 2h to allow the hygroscopic organic matter and inorganic salt to recombine through hydrogen bonds and coordination bonds, and introduce active groups through silane coupling agent to obtain a stable hygroscopic wetting solution;

[0181] (3) Impregnation of carbon fiber rods: The conductive skeleton obtained by gradient carbonization is placed in a hygroscopic impregnation solution for ordinary impregnation;

[0182] (4) Interface bonding and shaping treatment: The impregnated carbon fiber rods were placed in a forced-air drying oven and dried at 80℃ for 4 hours to remove moisture and allow the moisture-absorbing coating to initially cure; then they were placed in a low-temperature tube furnace, protected by nitrogen, and heated to 150℃ at a rate of 2℃ / min and held for 1 hour. The moisture-absorbing coating and the conductive skeleton were covalently bonded at the interface through the crosslinking reaction of the silane coupling agent. After natural cooling, carbon fiber rods with a conductive skeleton-moisture-absorbing coating core-shell structure were obtained, namely, a carbon-based composite material with a self-moisture-absorbing-conductive synergistic core-shell structure. The diameter of the core layer was 5~15μm and the specific surface area was 700m². 2 / g, with a shell thickness of approximately 400 nm.

[0183] Tests showed that the self-absorbing moisture rates of this self-hygroscopic-conductive synergistic core-shell carbon-based composite material were 1.7 g / (g·h), 2.5 g / (g·h), and 3.0 g / (g·h) at humidity levels of 30%, 60%, and 90%, respectively; the electrical resistance of this self-hygroscopic-conductive synergistic core-shell carbon-based composite material was 2.0 Ω, and its resistivity was 2.4 Ω. 10 -3 Ω·m; can be cycled 50 times, moisture absorption rate decay rate is 9.2%, and resistance decay rate is 10.8%.

[0184] When a voltage of 220 V is applied, the initial formaldehyde concentration is 100 mg / m³. 3 Under the conditions of a reaction time of 1 hour, a reaction chamber volume of 1 m³, and a carbon fiber rod dosage of 0.5 g, the carbon fiber rod's formaldehyde decomposition efficiency was 78.5%, and all performance characteristics decreased.

[0185] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0186] It should be understood that the above embodiments are merely illustrative of the technical concept and features of the present invention, and are intended to enable those skilled in the art to understand the content of the present invention and implement it accordingly. They should not be construed as limiting the scope of protection of the present invention. All equivalent changes or modifications made in accordance with the spirit and essence of the present invention should be covered within the scope of protection of the present invention.

Claims

1. A self-hygroscopic and conductive synergistic core-shell structure carbon-based composite material, characterized in that, include: The system comprises a core layer and a shell layer covering the core layer; wherein the core layer is a conductive carbon matrix serving as a conductive framework, which is prepared by multiple gradient carbonization processes of carbon fiber rods; the shell layer is a hygroscopic coating composed of hygroscopic organic matter and hygroscopic inorganic salt at the molecular level, comprising a molecular-level composite system of hygroscopic components formed by hydrogen bonds and coordination bonds, wherein the hygroscopic components have hydrophilic functional groups, the mass ratio of the hygroscopic organic matter to the hygroscopic inorganic salt is 1~5:1~3, the core layer and the shell layer form a covalently bonded interface through a silane coupling agent, and the conductive carbon matrix has a diameter of 5~20 μm and a specific surface area of ​​800~1200 m². 2 / g; The self-hygroscopic-conductive synergistic core-shell structure carbon-based composite material contains 85-90 wt% conductive carbon matrix, 1-5 wt% silane coupling agent, and 5-14 wt% hygroscopic component.

2. The self-hygroscopic-conductive synergistic core-shell structure carbon-based composite material according to claim 1, characterized in that: The conductive carbon matrix is ​​prepared by three-stage gradient carbonization of the original carbon fiber rod.

3. The self-hygroscopic-conductive synergistic core-shell structure carbon-based composite material according to claim 2, characterized in that, The method for preparing the conductive carbon matrix includes: In a protective atmosphere, the original carbon fiber rod is subjected to a first treatment prior to the first temperature to remove internal volatile molecules; The carbon fiber rod is heated to a second temperature to perform a second treatment, so that the organic matter on the surface of the carbon fiber rod is carbonized to form an amorphous carbon matrix. The carbon fiber rod is heated to a third temperature to perform a third treatment, so that the interface between the carbon fiber rod and the carbonized organic matter is fused and the structure is reconstructed to obtain a conductive carbon matrix. The second temperature is greater than the first temperature and less than the third temperature.

4. The self-hygroscopic-conductive synergistic core-shell structure carbon-based composite material according to claim 3, characterized in that: The protective atmosphere is formed by a protective gas, including nitrogen. And / or, the temperature is raised to a first temperature at a heating rate of 1~5℃ / min, the first temperature is 200~300℃, and the holding time of the first treatment is 1~2h; The temperature is increased to the second temperature at a heating rate of 1~3℃ / min, the second temperature is 500~600℃, and the holding time of the second treatment is 2~3h; The temperature is increased to a third temperature at a heating rate of 1~2℃ / min, the third temperature being 800~1000℃, and the holding time for the third treatment is 1~2h.

5. The self-hygroscopic-conductive synergistic core-shell structure carbon-based composite material according to claim 1, characterized in that: The silane coupling agent includes one or more combinations of γ-glycidoxypropyltrimethoxysilane, γ-methacryloxypropyltrimethoxysilane, and γ-methacryloxypropyltriethoxysilane.

6. The self-hygroscopic-conductive synergistic core-shell structure carbon-based composite material according to claim 1, characterized in that: The thickness of the moisture-absorbing coating is 100~500 nm; And / or, the hydrophilic functional group includes a sulfonic acid group or an ammonium group.

7. The self-hygroscopic-conductive synergistic core-shell structure carbon-based composite material according to claim 6, characterized in that: The hygroscopic organic matter includes one or a combination of two of sulfonate organic matter and ammonium salt organic matter. The sulfonate organic matter includes one or a combination of sodium camphor sulfonate, 2-acrylamido-2-methylpropanesulfonate, sodium dodecyl sulfonate, hexadecyltrimethylammonium p-toluenesulfonate, and sodium polystyrene sulfonate. The ammonium salt organic matter includes one or a combination of ammonium acetate, ammonium formate, triammonium citrate, and dodecyltrimethylammonium chloride. And / or, the hygroscopic inorganic salt includes one or more combinations of calcium chloride, magnesium chloride, and lithium chloride.

8. The self-hygroscopic-conductive synergistic core-shell structure carbon-based composite material according to claim 1, characterized in that: At a room temperature of 25°C and a humidity of 30-90%, the self-hygroscopic-conductive synergistic core-shell structure carbon-based composite material exhibits a self-hygroscopic rate of 2.5-9.0 g / (g·h), can be cycled 500-1000 times, and has a moisture absorption rate decay rate ≤10%. And / or, the moisture absorption performance retention rate of the self-hygroscopic-conductive synergistic core-shell structure carbon-based composite material is ≥91.8%, and the resistance retention rate is ≥95.5%; And / or, the self-hygroscopic-conductive synergistic core-shell structured carbon-based composite material has a resistance of 0.5~2.0 Ω and a resistivity of 1.0*10⁻⁶. -4 ~1.0*10 -2 Ω·m; And / or, the self-hygroscopic-conductive synergistic core-shell structured carbon-based composite material, when energized, can initiate electrolytic dissociation to generate H. + H + It combines with water molecules to form H3O + The sulfonate group is attracted to H3O by electrostatic attraction. + It combines with volatile organic compounds and undergoes a redox reaction, causing them to decompose into carbon dioxide and water; And / or, when a DC voltage of 220 V is applied and the initial concentration of volatile organic compounds is 100 mg / m³ 3 The reaction time is 1 hour, and the reaction chamber volume is 1 m³. 3 Under the condition that the amount of self-hygroscopic-conductive synergistic core-shell structure carbon-based composite material is 0.5 g, the decomposition efficiency of volatile organic compounds is ≥95%.

9. A method for preparing a self-hygroscopic and conductive synergistic core-shell structured carbon-based composite material, characterized in that, include: The original carbon fiber rods were subjected to multiple gradient carbonization processes to obtain a conductive carbon matrix that serves as a conductive framework. The conductive carbon matrix has a diameter of 5–20 μm and a specific surface area of ​​800–1200 m². 2 / g; A molecular-level hygroscopic wetting liquid containing a hygroscopic component and a silane coupling agent is provided. The hygroscopic component comprises a molecular-level composite system formed by hygroscopic organic matter and hygroscopic inorganic salt through hydrogen bonds and coordination bonds. The hygroscopic component has hydrophilic functional groups, and the mass ratio of the hygroscopic organic matter to the hygroscopic inorganic salt is 1~5:1~3. The conductive carbon matrix is ​​immersed in the molecular-level hygroscopic wetting liquid for molecular-level wetting and composite. By utilizing capillary action and molecular diffusion effect, the hygroscopic components and silane coupling agent penetrate to the surface of the conductive carbon matrix to achieve molecular-level composite. The conductive carbon matrix after molecular-level impregnation and composite is subjected to interfacial bonding and shaping treatment to form a hygroscopic coating on the surface of the conductive carbon matrix. The hygroscopic coating and the conductive carbon matrix are then covalently bonded at the interface through the cross-linking reaction of silane coupling agent, thus obtaining a self-hygroscopic-conductive synergistic core-shell structure carbon-based composite material. The self-hygroscopic-conductive synergistic core-shell structure carbon-based composite material contains 85-90 wt% conductive carbon matrix, 1-5 wt% silane coupling agent, and 5-14 wt% hygroscopic component.

10. The preparation method according to claim 9, characterized in that, include: The conductive carbon matrix was prepared by performing three gradient carbonizations on the original carbon fiber rods.

11. The preparation method according to claim 10, characterized in that, include: In a protective atmosphere, the original carbon fiber rod is subjected to a first treatment prior to the first temperature to remove internal volatile molecules; The carbon fiber rod is heated to a second temperature to perform a second treatment, so that the organic matter on the surface of the carbon fiber rod is carbonized to form an amorphous carbon matrix. The carbon fiber rod is heated to a third temperature to perform a third treatment, so that the interface between the carbon fiber rod and the carbonized organic matter is fused and the structure is reconstructed to obtain a conductive carbon matrix. The second temperature is greater than the first temperature and less than the third temperature.

12. The preparation method according to claim 11, characterized in that: The protective atmosphere is formed by a protective gas, including nitrogen. And / or, the temperature is raised to a first temperature at a heating rate of 1~5℃ / min, the first temperature is 200~300℃, and the holding time of the first treatment is 1~2h; The temperature is increased to the second temperature at a heating rate of 1~3℃ / min, the second temperature is 500~600℃, and the holding time of the second treatment is 2~3h; The temperature is increased to a third temperature at a heating rate of 1~2℃ / min, the third temperature being 800~1000℃, and the holding time for the third treatment is 1~2h.

13. The preparation method according to claim 9, characterized in that: The hydrophilic functional group includes a sulfonic acid group or an ammonium salt.

14. The preparation method according to claim 13, characterized in that, include: Hygroscopic organic matter, hygroscopic inorganic salt, and water are mixed to form a mixed solution with a mass fraction of 10% to 32%. Then, a silane coupling agent is added, and the mixture is stirred at 50 to 60°C for 2 to 3 hours to allow the hygroscopic organic matter and inorganic salt to recombine through hydrogen bonds and coordination bonds, thus obtaining a molecular-level hygroscopic wetting solution.

15. The preparation method according to claim 14, characterized in that: The hygroscopic organic matter includes one or a combination of two of sulfonate organic matter and ammonium salt organic matter. The sulfonate organic matter includes one or a combination of sodium camphor sulfonate, 2-acrylamido-2-methylpropanesulfonate, sodium dodecyl sulfonate, hexadecyltrimethylammonium p-toluenesulfonate, and sodium polystyrene sulfonate. The ammonium salt organic matter includes one or a combination of ammonium acetate, ammonium formate, triammonium citrate, and dodecyltrimethylammonium chloride. And / or, the hygroscopic inorganic salt includes one or more combinations of calcium chloride, magnesium chloride, and lithium chloride.

16. The preparation method according to claim 9, characterized in that: The silane coupling agent includes one or more combinations of γ-glycidoxypropyltrimethoxysilane, γ-methacryloxypropyltrimethoxysilane, and γ-methacryloxypropyltriethoxysilane. And / or, the mass ratio of the hygroscopic component to the silane coupling agent is 5~14:1~5.

17. The preparation method according to claim 9, characterized in that, include: The conductive carbon matrix is ​​immersed in the molecular-level hygroscopic wetting solution. First, a vacuum is drawn to -0.08 to -0.1 MPa and held for 10 to 20 minutes. Then, the pressure is restored to normal and the temperature is raised to 40 to 60°C and held for 1 to 2 hours to achieve molecular-level composite.

18. The preparation method according to claim 9, characterized in that, include: The conductive carbon matrix after molecular-level impregnation and composite is dried at 80~100℃ for 4~6h to allow the moisture-absorbing coating to initially cure. Then, in a protective atmosphere, the self-hygroscopic-conductive synergistic core-shell structured carbon-based composite material was prepared by holding it at 150~200℃ for 1~2 hours.

19. A self-hygroscopic and conductive synergistic core-shell structured carbon-based composite material prepared by any one of claims 9 to 18.

20. The application of the self-hygroscopic-conductive synergistic core-shell structure carbon-based composite material according to any one of claims 1 to 8 and 19 in the purification of gaseous pollutants mediated by hydrated hydrogen ions.

21. The application according to claim 20, characterized in that: The applications include indoor air purification or industrial waste gas pretreatment.

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