Material treatment method based on electrothermal vacuum sublimation and application thereof

Abstract

The invention provides a material treatment method based on electrothermal vacuum sublimation and application of the material treatment method, and relates to the technical field of material synthesis and treatment technologies. The treatment method comprises the following steps: sequentially carrying out freezing treatment, vacuumizing treatment and electric heating treatment on a water-containing material to obtain a treated material. According to the material treatment method based on electrothermal vacuum sublimation, through three-stage cooperative control of freezing, vacuum and electric heating, integrated operation of four functions in a single device is achieved for the first time, and various nanoparticles such as silicon, platinum, nickel and sodium chloride can be efficiently prepared; carbon and water can be driven to react for in-situ synthesis of carbon monoxide and hydrogen; oxygen-containing functional groups of materials such as graphene oxide can be removed; rapid low-loss drying of fragile porous materials such as graphene aerogel and MXene aerogel can be completed; the integrated design greatly improves the function density and process compatibility of the equipment, and meets the multifunctional requirements of laboratory research and development and large-scale production.

Description

Technical Field

[0001] This invention relates to materials synthesis and processing technology, and in particular to a method for processing materials based on electrothermal vacuum sublimation and its application. Background Technology

[0002] In the field of materials science and engineering, the synthesis, drying, and surface modification of materials are the core steps that determine their final performance and application scenarios. Especially in strategic emerging fields such as new energy and advanced composite materials, more stringent requirements are placed on the efficiency, precision, and multi-scenario adaptability of processing technologies. Although current mainstream material processing and synthesis technologies have achieved large-scale application, significant bottlenecks still exist in terms of multi-scenario adaptability, performance-cost balance, and the preparation of complex materials.

[0003] Taking material synthesis as an example, traditional technologies mostly rely on tube furnaces, ovens, and chemical vapor deposition (CVD) equipment, but they have significant shortcomings in terms of temperature control flexibility and process efficiency: firstly, the heating and cooling rates are slow; secondly, the upper temperature limit and uniformity are limited. Furthermore, in existing technology systems, drying, synthesis, and surface modification are usually completed using independent equipment, lacking an integrated solution that can cover multiple scenarios. Against this backdrop, developing a material processing and synthesis technology that combines high efficiency, low damage, and multifunctionality has become crucial for overcoming current technological bottlenecks and promoting the large-scale application of high-end materials. The electrothermal vacuum sublimation-based technical solution proposed in this application addresses these pain points by synergistically combining three key elements: low-temperature freezing, vacuum environment, and ultrafast precise electrothermal temperature control, to achieve efficient material processing and synthesis in multiple scenarios, filling a gap in existing technologies.

[0004] Furthermore, existing drying technologies present a significant contradiction in balancing the requirements of "efficiency, structure preservation, and energy consumption," especially for materials with porous frameworks such as graphene aerogels and metal-organic frameworks (MOFs). Specifically: Freeze-drying technology, while avoiding the collapse of the skeletal structure caused by capillary forces of liquid water through the sublimation of ice (e.g., the volume shrinkage rate of graphene aerogel can be controlled at 6-8%), has two major problems: First, the drying cycle is extremely long; traditional processes require 36-40 hours to process graphene hydrogels of the same specifications, resulting in low production efficiency. Second, the low-temperature environment (usually -50 to -20 ℃) ​​cannot effectively eliminate residual oxygen-containing functional groups (such as hydroxyl and epoxy groups in graphene oxide) on the material surface, requiring additional secondary treatment through tube furnace annealing. This process not only increases the cost of the process but may also damage the skeletal structure due to high temperatures.

[0005] Blow-air drying technology relies on high-temperature hot air to accelerate moisture evaporation. Although the processing cycle is shorter than freeze drying (e.g., graphene hydrogels only require 10-12 hours), the capillary action of liquid water at normal pressure can cause severe shrinkage of porous materials, completely destroying their porous structure and causing them to lose their original functions. At the same time, the high-temperature environment can easily cause oxidation of the material surface or volatilization of components, thus limiting its applicability.

[0006] Supercritical drying technology, while capable of achieving low shrinkage drying, relies on high-pressure equipment (typically 10-30 MPa) and special solvents (such as CO2), resulting in drawbacks such as high equipment investment and complex operation. Furthermore, this process is difficult to scale up for large-size or irregularly shaped materials, leading to persistently high costs.

[0007] Therefore, it is of great significance to develop a device that can both synthesize and modify the material and dry the fragile skeleton.

[0008] In view of this, the present invention is hereby proposed. Summary of the Invention

[0009] The purpose of this invention is to provide a material processing method based on electrothermal vacuum sublimation and its application. The processing method can simultaneously achieve efficient synthesis of nanoparticles and gases, modification of material surface functional groups, and drying of the fragile skeleton of aerogel materials.

[0010] In order to achieve the above-mentioned objectives of the present invention, the following technical solution is adopted: In a first aspect, the present invention provides a method for processing materials based on electrothermal vacuum sublimation, the method comprising: The water-containing material is subjected to freezing, vacuuming, and electric heating in sequence to obtain the processed material.

[0011] Furthermore, the freezing process includes: freezing the water-containing material in a low-temperature environment to obtain an ice-containing material.

[0012] Furthermore, the freezing temperature is -70 to 0 °C.

[0013] Furthermore, the vacuuming process includes: evacuating the cavity of the device.

[0014] Furthermore, the pressure of the vacuuming process is below 660 Pa.

[0015] Furthermore, the electric heating treatment includes: applying current through a power supply device to raise the temperature of the resistance heating material, performing electric heating treatment, and obtaining the treated material.

[0016] Furthermore, the electric heating treatment method includes any one or a combination of at least two of Joule heating, induction heating, infrared heating, and laser heating, preferably Joule heating.

[0017] Furthermore, the electric heating process includes continuous heating and / or pulsed heating.

[0018] Furthermore, the temperature of the electric heating treatment is 25~1500 ℃, the heating rate of the electric heating treatment is 10~1000 ℃ / s, and the time of the electric heating treatment is 0.01 s~100 min.

[0019] In a second aspect, the present invention provides an application of the material processing method based on electrothermal vacuum sublimation as described in the first aspect in nanoparticle preparation, gas synthesis, material surface modification, and aerogel drying.

[0020] Thirdly, the present invention provides a method for preparing nanoparticles, the method comprising: The precursor and water are mixed to obtain an aqueous solution of the precursor; the aqueous solution of the precursor is subjected to freezing treatment, vacuum treatment and electric heating treatment in sequence to obtain nanoparticles of the precursor.

[0021] Furthermore, the precursor includes any one or a combination of at least two of sodium chloride, potassium chloride, calcium chloride, sodium nitrate, potassium nitrate, sodium sulfate, and potassium sulfate.

[0022] Furthermore, the particle size of the precursor is 1~100 μm.

[0023] Furthermore, the precursor in the aqueous solution contains 0.1 to 5 wt% of the precursor.

[0024] Furthermore, the freezing temperature is -100 to 0 °C.

[0025] Furthermore, the pressure of the vacuuming process is below 10 Pa.

[0026] Furthermore, the electric heating treatment is performed by Joule heating; the electric heating treatment procedure is pulse heating; and a vacuum process is continuously performed during the electric heating treatment.

[0027] Furthermore, the pulse heating process includes: heating for 0.01 to 1 s, cooling for 0.1 to 10 s, and a peak heating temperature of 100 to 450 ℃.

[0028] Furthermore, the precursor nanoparticles have a particle size of less than 100 nm.

[0029] Fourthly, the present invention provides a method for preparing carbon-supported nanoparticles, the method comprising: The precursor, carbon support, and water are mixed to obtain a mixed solution; the mixed solution is then subjected to freezing, vacuuming, and electrothermal treatment in sequence to obtain carbon-loaded nanoparticles.

[0030] Furthermore, the precursor includes silicon particles and / or a metal source.

[0031] Furthermore, the metal source includes any one or a combination of at least two of the following: platinum chloride, nickel chloride, copper chloride, ferric chloride, cobalt chloride, copper nitrate, nickel nitrate, copper sulfate, and nickel sulfate.

[0032] Furthermore, the particle size of the silicon particles is 1~50 μm.

[0033] Furthermore, the particle size of the metal source is 1~100 μm.

[0034] Furthermore, the carbon support includes any one or a combination of at least two of porous carbon, graphene oxide, graphene film, carbon fiber, carbon cloth, and carbon felt.

[0035] Furthermore, the mass ratio of the precursor to the carbon support is (1~10):(99~90).

[0036] Furthermore, the mass ratio of the water to the solid material is (1~10):1.

[0037] Furthermore, the freezing temperature is -20 to 0 °C.

[0038] Furthermore, the pressure of the vacuuming process is below 10 Pa.

[0039] Furthermore, the electric heating treatment is performed by Joule heating; the electric heating treatment procedure is pulse heating; and a vacuum process is continuously performed during the electric heating treatment.

[0040] Furthermore, the pulse heating process includes: heating for 0.01 to 1 s, cooling for 0.1 to 5 s, and a peak heating temperature of 300 to 1300 ℃.

[0041] Furthermore, the particle size of the carbon-supported nanoparticles is less than 50 nm.

[0042] Fifthly, the present invention provides a method for gas synthesis, the gas synthesis comprising: Porous carbon and water are mixed to obtain an aqueous dispersion of porous carbon; the aqueous dispersion of porous carbon is then subjected to freezing treatment, vacuum treatment and electric heating treatment in sequence to obtain carbon monoxide and hydrogen.

[0043] Furthermore, the mass ratio of the porous carbon to water is 1:(1~20).

[0044] Furthermore, the freezing temperature is -20 to 0 °C.

[0045] Furthermore, the pressure of the vacuuming process is below 10 Pa.

[0046] Furthermore, the electric heating treatment is performed by Joule heating; the electric heating treatment procedure is continuous heating; and a vacuum process is continuously performed during the electric heating treatment.

[0047] Furthermore, the continuous heating temperature is 350~900 ℃, and the continuous heating time is 1~10 min.

[0048] Furthermore, the molar ratio of hydrogen to carbon monoxide is (1~1.2):1.

[0049] Sixthly, the present invention provides a method for modifying the surface oxygen functional groups of graphene oxide, the method comprising: Graphene oxide and water are mixed to obtain an aqueous dispersion of graphene oxide; the aqueous dispersion of graphene oxide is subjected to freezing treatment, vacuum treatment and electric heating treatment in sequence to reduce the graphene oxide and obtain graphene oxide modified with surface oxygen functional groups.

[0050] Furthermore, the mass ratio of the graphene oxide to water is 1:(100~300).

[0051] Furthermore, the freezing temperature is -30 to -10 °C.

[0052] Furthermore, the pressure of the vacuuming process is below 10 Pa.

[0053] Furthermore, the electric heating treatment is performed by Joule heating; the electric heating treatment procedure is continuous heating; and a vacuum process is continuously performed during the electric heating treatment.

[0054] Furthermore, the continuous heating temperature is 400~700 ℃, and the continuous heating time is 1~20 min.

[0055] Furthermore, the content of oxygen-containing functional groups in the surface oxygen-functionalized graphene oxide is reduced by 60-80% compared to the content of oxygen-containing functional groups in untreated graphene oxide.

[0056] In a seventh aspect, the present invention provides a method for drying an aerogel, the method comprising: The hydrogel or dispersion is subjected to freezing, vacuuming and electric heating in sequence to obtain a dry aerogel; wherein the dry aerogel includes dry graphene aerogel or dry MXene aerogel.

[0057] Furthermore, the freezing temperature is -30 to -10 °C.

[0058] Furthermore, the pressure of the vacuuming process is below 10 Pa.

[0059] Furthermore, the electric heating treatment is performed by Joule heating; the electric heating treatment procedure is continuous heating; and a vacuum process is continuously performed during the electric heating treatment.

[0060] Furthermore, when the dried aerogel is dried graphene aerogel, the continuous heating temperature is 100~500 ℃, and the continuous heating time is 8~60 min.

[0061] Furthermore, when the dried aerogel is a dried MXene aerogel, the continuous heating temperature is 70~120 ℃, and the continuous heating time is 8~60 min.

[0062] Furthermore, the hydrogel is prepared by the following steps: mixing graphene oxide, a reducing agent and water, and then subjecting the mixture to a hydrothermal reaction to obtain the hydrogel.

[0063] Furthermore, the mass ratio of the graphene oxide, reducing agent, and water is 1:(0.1~1):(100~300).

[0064] Furthermore, the reducing agent is ascorbic acid.

[0065] Furthermore, the temperature of the hydrothermal reaction is 70~90 ℃, and the time of the hydrothermal reaction is 12~36 h.

[0066] Further, the dispersion is prepared by the following steps: mixing MXene and water, and then dispersing by ultrasonication to obtain an MXene dispersion.

[0067] Furthermore, the mass ratio of MXene to water is 1:(50~300).

[0068] Furthermore, the MXene species include one or a combination of several of Ti2C, Ti3C2, V2C, Nb2C, Ta4C3, and Mo2C.

[0069] Furthermore, the porosity of the dried graphene aerogel is over 90%.

[0070] Furthermore, the MXene includes any one or a combination of at least two of Ti2C, Ti3C2, V2C, Nb2C, Ta4C3, and Mo2C.

[0071] Compared with the prior art, the present invention has the following beneficial effects: (1) The material processing method based on electrothermal vacuum sublimation described in this invention achieves integrated operation of four major functions in a single device for the first time through the three-stage coordinated control of "freezing-vacuum-electric heating": it can efficiently prepare various nanoparticles such as silicon, platinum, nickel, and sodium chloride; it can drive the in-situ synthesis of carbon monoxide and hydrogen through the reaction of carbon and water; it can remove oxygen-containing functional groups (i.e., surface reduction modification) of materials such as graphene oxide; it can complete the rapid and low-loss drying of fragile porous structures such as graphene aerogel; this integrated design greatly improves the functional density and process compatibility of the equipment, and is suitable for the multifunctional needs of laboratory research and development and large-scale production.

[0072] (2) The material processing method based on electrothermal vacuum sublimation described in this invention can be used to efficiently prepare nanoparticles, achieve uniform fixation of precursors and ultrafast thermal shock decomposition, effectively inhibit grain growth and agglomeration; in addition, combined with pulse heating and carrier, it promotes automatic powder shedding, obtains highly dispersed, small-sized nanoparticles, and has the advantages of high efficiency, energy saving and anti-sintering, which is significantly better than traditional freeze drying and long-term high-temperature treatment methods.

[0073] (3) The material processing method based on electrothermal vacuum sublimation described in this invention can be used for gas synthesis. It can rapidly heat up to promote the efficient pyrolysis or reduction reaction of solid water and reactants such as carbon, generating gases such as carbon monoxide and hydrogen in situ. The reaction rate is fast, the gas production efficiency is high, and the energy consumption is low and the process is clean, with good controllability and safety.

[0074] (4) The material processing method based on electrothermal vacuum sublimation described in this invention can be used for surface modification of materials. It can effectively remove oxygen-containing functional groups on the surface of materials such as graphene oxide, achieve one-step reduction, avoid damage to the structure by capillary force of liquid water, and prevent the skeleton from being destroyed due to long-term exposure to high temperature. It has the advantages of high efficiency, low loss and energy saving, and is significantly better than traditional reduction processes.

[0075] (5) The material processing method based on electrothermal vacuum sublimation described in this invention strictly follows the phase diagram path of water, avoids the appearance of liquid water during the direct sublimation of solid ice into water vapor, and fundamentally eliminates the damage of capillary force to the porous skeleton; it can ensure the integrity of the three-dimensional network structure of the material, with abundant pores, effectively maintaining the original high specific surface area and functionality of the material, and is suitable for low-loss drying processing of sensitive materials such as MOFs and aerogels. Attached Figure Description

[0076] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0077] Figure 1 The present invention provides a phase diagram of water and a path diagram for electrothermal vacuum ascent.

[0078] Figure 2 A diagram of a material processing apparatus based on electrothermal vacuum sublimation provided by the present invention.

[0079] Figure 3 The XRD characterization diagram of the sodium chloride nanoparticles provided in Example 1.

[0080] Figure 4 The image shows the SEM characterization of the sodium chloride nanoparticles provided in Example 1.

[0081] Figure 5 The particle size distribution diagram of sodium chloride particles provided in Example 1.

[0082] Figure 6 The image shows the XRD characterization of the peak changes before and after silicon particle treatment provided in Example 2.

[0083] Figure 7 The image shows the SEM characterization of the particle size change of silicon particles before and after treatment, as provided in Example 2.

[0084] Figure 8 The image shows the XRD characterization of the platinum nanoparticles provided in Example 3.

[0085] Figure 9 The image shows the SEM characterization of the platinum nanoparticles provided in Example 3.

[0086] Figure 10 The image shows the XRD characterization of the nickel nanoparticles provided in Example 4.

[0087] Figure 11 The image shows the TEM characterization of the nickel nanoparticles provided in Example 4.

[0088] Figure 12 The gas chromatogram of the product gas provided in Example 5.

[0089] Figure 13 The image shows the XPS characterization results of the graphene oxide raw material provided in Example 6.

[0090] Figure 14The XPS characterization results of the graphene aerogel obtained by electrothermal vacuum ascent drying in Example 6 are shown in the figure.

[0091] Figure 15 Optical photographs and SEM characterization results of the graphene aerogel provided in Example 7.

[0092] Figure 16 The XRD characterization results, optical images, and SEM-EDS characterization results of the MXene aerogel provided in Example 12. Detailed Implementation

[0093] Unless otherwise defined herein, the scientific and technical terms used in conjunction with this invention shall have the meanings commonly understood by one of ordinary skill in the art. The meaning and scope of terms shall be clear; however, in any case of potential ambiguity, the definitions provided herein shall prevail over any dictionary or foreign definitions. In this application, unless otherwise stated, the use of "or" means "and / or". Furthermore, the use of the term "comprising" and other forms is non-limiting.

[0094] The technical solution of the present invention will be clearly and completely described below with reference to the embodiments. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0095] In a first aspect, the present invention provides a method for processing materials based on electrothermal vacuum sublimation, the method comprising: The water-containing material is subjected to freezing, vacuuming, and electric heating in sequence to obtain the processed material.

[0096] It should be noted that this invention provides a method for processing materials based on electrothermal vacuum sublimation, comprising the following steps: This method is based on a phase diagram ( Figure 1 The method follows the path shown in the diagram. Specific operations include: freezing the water-containing material in a low-temperature environment, such as using a refrigerator, cold trap, or liquid nitrogen for cooling; starting the vacuum pump; applying a suitable current through the power supply to rapidly raise the temperature of the resistance-heated material, maintaining this temperature for a certain period, and then removing the sample. The electrothermal sublimation process in this method consists of three stages: stage 1 is cooling, stage 2 is vacuuming, and stage 3 is heating. This method successfully prepared various nanoparticles, carbon monoxide, and hydrogen using electrothermal vacuum sublimation to modify the functional groups on the surface of graphene oxide and dry graphene aerogel. As a novel material processing method, it features rapid heating and cooling, a high upper temperature limit, and a wide range of applications, suitable for both material synthesis and modification, as well as drying fragile framework materials.

[0097] It should be noted that the method strictly follows the order of freezing, vacuuming, and electric heating. This is because if the water-containing material is vacuumed immediately before being frozen into ice, the liquid water will evaporate rapidly, which has many adverse effects. The resulting capillary force is detrimental to the fragile aerogel structure; ice cannot act as a barrier to prevent the aggregation of nanoparticles; and a large amount of water, as a reactant, will evaporate, resulting in waste.

[0098] As an optional implementation method, such as Figure 2 As shown, the material processing method based on electrothermal vacuum sublimation is carried out using a material processing device based on electrothermal vacuum sublimation; wherein, the device includes: a cold trap (which can be replaced by other refrigeration equipment such as a refrigerator), a vacuum pump, a sealed cavity, a programmable DC power supply, a resistance heating material, and electrodes.

[0099] As an optional implementation, the freezing process includes: freezing the water-containing material in a low-temperature environment to obtain an ice-containing material.

[0100] As an optional implementation, the low-temperature environment includes methods such as refrigerators, cold traps, or liquid nitrogen cooling.

[0101] As an optional implementation, the freezing temperature is -70~0℃, for example, it can be -70℃, -65℃, -60℃, -55℃, -50℃, -45℃, -40℃, -35℃, -30℃, -25℃, -20℃, -15℃, -10℃, -5℃, 0℃, etc.

[0102] As an optional implementation, the vacuuming process includes: evacuating the cavity of the device to a vacuum.

[0103] As an optional implementation, the pressure of the vacuuming process is below 660 Pa, for example, it can be 660 Pa, 560 Pa, 460 Pa, 360 Pa, 260 Pa, 160 Pa, 60 Pa, 55 Pa, 50 Pa, 45 Pa, 40 Pa, 35 Pa, 30 Pa, 25 Pa, 20 Pa, 15 Pa, 10 Pa, 5 Pa, 0.1 Pa, etc.

[0104] As an optional implementation, the electroheating treatment includes: applying current through a power supply device to raise the temperature of the resistance heating material, performing electroheating treatment, and obtaining the treated material.

[0105] As an optional implementation, the electric heating treatment method includes any one or a combination of at least two of Joule heating, induction heating, infrared heating, and laser heating.

[0106] In a preferred embodiment, the electric heating treatment is Joule heating.

[0107] As an optional implementation, the electric heating process includes continuous heating and / or pulsed heating.

[0108] As an optional implementation, the resistance heating material for the electric heating treatment includes any one or a combination of at least two of the following: carbon paper, carbon felt, carbon cloth, carbon fiber, graphite film, graphene film, and high melting point metal.

[0109] It should be noted that the resistance heating material of the electrothermal vacuum sublimation device in this invention can be a carbon-based material, or a metal material, ceramic material, etc., that is non-reactive to the substance to be dried, has a high melting point, and suitable electrical conductivity. A preferred resistance heating material is a high-melting-point, highly conductive tungsten mesh, which allows the dried powder to fall off the high-temperature zone in a timely manner, reducing the risk of sintering.

[0110] As an optional implementation, the electrode for the electric heating process is made of a metal with excellent electrical conductivity.

[0111] As an optional implementation, the metal with excellent conductivity includes any one or a combination of at least two of copper, iron, and silver.

[0112] As an optional implementation, the heat transfer method of the electric heating treatment is both direct contact heat transfer and radiation heat transfer, which can utilize thermal energy more efficiently.

[0113] As an optional implementation, the temperature of the electric heating treatment is 25~1500℃, for example, it can be 25℃, 50℃, 75℃, 100℃, 125℃, 150℃, 175℃, 200℃, 225℃, 250℃, 275℃, 300℃, 325℃, 350℃, 375℃, 400℃, 425℃, 450℃, 475℃, 500℃, 525℃, 550℃, 575℃, 600℃, 625℃, 650℃, 675℃, 700℃, 725℃, 750℃, 775℃, 800℃, 825℃, 850℃, 875℃, 900℃, 925℃, 950℃. Temperatures include ℃, 975℃, 1000℃, 1025℃, 1050℃, 1075℃, 1100℃, 1125℃, 1150℃, 1175℃, 1200℃, 1225℃, 1250℃, 1275℃, 1300℃, 1325℃, 1350℃, 1375℃, 1400℃, 1425℃, 1450℃, 1475℃, 1500℃, etc.

[0114] As an optional implementation, the heating rate of the electric heating treatment is 10~1000 ℃ / s, for example, it can be 10 ℃ / s, 50 ℃ / s, 100 ℃ / s, 150 ℃ / s, 200 ℃ / s, 250 ℃ / s, 300 ℃ / s, 350 ℃ / s, 400 ℃ / s, 450 ℃ / s, 500 ℃ / s, 550 ℃ / s, 600 ℃ / s, 650 ℃ / s, 700 ℃ / s, 750 ℃ / s, 800 ℃ / s, 850 ℃ / s, 900 ℃ / s, 950 ℃ / s, 1000 ℃ / s, etc.

[0115] As an optional implementation, the time for the electric heating treatment is 0.01 s to 100 min, for example, it can be 0.01 s, 0.1 s, 1 s, 30 s, 1 min, 5 min, 10 min, 15 min, 20 min, 25 min, 30 min, 35 min, 40 min, 45 min, 50 min, 55 min, 60 min, 65 min, 70 min, 75 min, 80 min, 85 min, 90 min, 95 min, 100 min, etc.

[0116] As an optional implementation, the input device used in the electric heating treatment can be controlled from three dimensions: voltage (0~80 V), current (0~667 A) and power (0~16 KW). Combined with programming, it can achieve instantaneous ultra-high current and voltage output, and achieve ultra-fast heating (1000 ℃ / s) to high temperature (~1500 ℃), which greatly reduces the time cost required for drying compared with the prior art.

[0117] In a second aspect, the present invention provides an application of the material processing method based on electrothermal vacuum sublimation as described in the first aspect in nanoparticle preparation, gas synthesis, material surface modification, and aerogel drying.

[0118] Thirdly, the present invention provides a method for preparing nanoparticles, the method comprising: The precursor and water are mixed to obtain an aqueous solution of the precursor; the aqueous solution of the precursor is subjected to freezing treatment, vacuum treatment and electric heating treatment in sequence to obtain nanoparticles of the precursor.

[0119] As an optional implementation, the method for preparing the nanoparticles includes the following steps: the method is based on a phase diagram ( Figure 1The path shown is as follows: Specific operation: Freeze the aqueous solution of the precursor in a low-temperature environment, which can be done by means of a refrigerator, cold trap or liquid nitrogen cooling; start the vacuum pump device; apply a suitable current through the power supply device to make the temperature of the resistance heating material rise rapidly, and take out the sample after the preparation is completed.

[0120] As an optional implementation, in the preparation of the nanoparticles, the precursor includes any one or a combination of at least two of sodium chloride, potassium chloride, calcium chloride, sodium nitrate, potassium nitrate, sodium sulfate, and potassium sulfate.

[0121] As an optional implementation, in the preparation of the nanoparticles, the particle size of the precursor is 1~100 μm, for example, it can be 1 μm, 5 μm, 10 μm, 15 μm, 20 μm, 25 μm, 30 μm, 35 μm, 40 μm, 45 μm, 50 μm, 55 μm, 60 μm, 65 μm, 70 μm, 75 μm, 80 μm, 85 μm, 90 μm, 95 μm, 100 μm, etc.

[0122] As an optional implementation, in the preparation of the nanoparticles, the mass percentage of the precursor in the aqueous solution of the precursor is 0.1~5 wt%, for example, it can be 0.1 wt%, 0.5 wt%, 1 wt%, 2 wt%, 3 wt%, 4 wt%, 5 wt%, etc.

[0123] As an optional implementation, in the preparation of the nanoparticles, the freezing temperature is -100~0℃, for example, it can be -100 ℃, -90 ℃, -80 ℃, -70 ℃, -60 ℃, -50 ℃, -40 ℃, -30 ℃, -20 ℃, -10 ℃, 0 ℃, etc.

[0124] As an optional implementation, in the preparation of the nanoparticles, the pressure of the vacuum treatment is below 10 Pa, for example, it can be 10 Pa, 9 Pa, 8 Pa, 7 Pa, 6 Pa, 5 Pa, 4 Pa, 3 Pa, 2 Pa, 1 Pa, 0.5 Pa, 0.1 Pa, etc.

[0125] As an optional implementation, in the preparation of the nanoparticles, the electrothermal treatment is performed by Joule heating.

[0126] As an optional implementation, in the preparation of the nanoparticles, the electrothermal treatment procedure is pulse heating.

[0127] As an optional implementation, a vacuum process is continuously performed during the preparation of the nanoparticles and the electrothermal treatment.

[0128] As an optional implementation, the pulse heating program includes: heating for 0.01~1s, cooling for 0.1~10s, and the peak heating temperature is 100~450℃.

[0129] As an optional implementation, in the preparation of the nanoparticles, the particle size of the precursor particles is less than 100 nm, for example, it can be 100 nm, 95 nm, 90 nm, 85 nm, 80 nm, 75 nm, 70 nm, 65 nm, 60 nm, 55 nm, 50 nm, 45 nm, 40 nm, 35 nm, 30 nm, 25 nm, 20 nm, 15 nm, 10 nm, 5 nm, 1 nm, etc.

[0130] In a preferred embodiment, the resistance heating material used for the electrothermal treatment in the preparation of the nanoparticles is a mesh metal.

[0131] It should be noted that, in the embodiments of the present invention for preparing nanoparticles, a mesh metal is preferred, which enables the powder to be transferred from the heat source in a timely manner by falling off, thus avoiding sintering.

[0132] In a preferred embodiment, the mesh metal is a mesh high-melting-point metal, such as any one or a combination of at least two of copper, tungsten, nickel, iron, and molybdenum.

[0133] It should be noted that in the preparation of the nanoparticles, the resistance heating material is connected between the two electrodes to form a circuit. When current flows through the resistance heating material, it generates a uniform thermal field. The intermittent heating method effectively limits particle agglomeration. Furthermore, the mesh structure of the resistance heating material also helps to separate and dry the sample, preventing further sintering. Scanning electron microscopy of the obtained product demonstrates that the silicon particle size decreases to nanometers under thermal shock.

[0134] Fourthly, the present invention provides a method for preparing carbon-supported nanoparticles, the method comprising: The precursor, carbon support, and water are mixed to obtain a mixed solution; the mixed solution is then subjected to freezing, vacuuming, and electrothermal treatment in sequence to obtain carbon-loaded nanoparticles.

[0135] As an optional implementation, the method for preparing the carbon-supported nanoparticles includes the following steps: the method is based on a phase diagram ( Figure 1 The path shown is as follows: Specific operation: Freeze the mixed solution in a low-temperature environment, such as by using a refrigerator, cold trap or liquid nitrogen cooling; start the vacuum pump device; apply a suitable current through the power supply device to make the temperature of the resistance heating material rise rapidly, and take out the sample after the preparation is completed.

[0136] As an optional implementation, in the preparation of the carbon-supported nanoparticles, the precursor includes silicon particles and / or a metal source.

[0137] As an optional implementation, in the preparation of the carbon-supported nanoparticles, the metal source includes any one or a combination of at least two of platinum chloride, nickel chloride, copper chloride, ferric chloride, cobalt chloride, copper nitrate, nickel nitrate, copper sulfate, and nickel sulfate.

[0138] As an optional implementation, in the preparation of the carbon-supported nanoparticles, the particle size of the silicon particles is 1~5 μm, for example, it can be 1 μm, 1.5 μm, 2 μm, 2.5 μm, 3 μm, 3.5 μm, 4 μm, 4.5 μm, 5 μm, etc.

[0139] As an optional implementation, in the preparation of the carbon-supported nanoparticles, the particle size of the metal source is 1~100 μm, for example, it can be 1 μm, 5 μm, 10 μm, 15 μm, 20 μm, 25 μm, 30 μm, 35 μm, 40 μm, 45 μm, 50 μm, 55 μm, 60 μm, 65 μm, 70 μm, 75 μm, 80 μm, 85 μm, 90 μm, 95 μm, 100 μm, etc.

[0140] As an optional implementation, in the preparation of the carbon-supported nanoparticles, the carbon support includes any one or a combination of at least two of porous carbon, graphene oxide, graphene film, carbon fiber, carbon cloth, and carbon felt.

[0141] As an optional implementation, in the preparation of the carbon-supported nanoparticles, the mass ratio of the precursor to the carbon support is (1~10):(99~90), for example, it can be 1:99, 2:98, 3:97, 4:96, 5:95, 6:94, 7:93, 8:92, 9:91, 10:90, etc.

[0142] As an optional implementation, in the preparation of the carbon-supported nanoparticles, the mass ratio of water to solid material is (1~10):1, for example, it can be 1:1, 2:1, 3:1, 4:1, 5:1, 6:1, 7:1, 8:1, 9:1, 10:1, etc.

[0143] As an optional implementation, in the preparation of the carbon-supported nanoparticles, the freezing temperature is -20~0 ℃, for example, it can be -20 ℃, -18 ℃, -16 ℃, -14 ℃, -12 ℃, -10 ℃, -8 ℃, -6 ℃, -4 ℃, -2 ℃, 0 ℃, etc.

[0144] As an optional implementation, in the preparation of the carbon-supported nanoparticles, the pressure of the vacuum treatment is below 10 Pa, for example, it can be 10 Pa, 9 Pa, 8 Pa, 7 Pa, 6 Pa, 5 Pa, 4 Pa, 3 Pa, 2 Pa, 1 Pa, 0.5 Pa, 0.1 Pa, etc.

[0145] As an optional implementation, in the preparation of the carbon-supported nanoparticles, the electrothermal treatment is performed by Joule heating.

[0146] As an optional implementation, in the preparation of the carbon-supported nanoparticles, the electrothermal treatment procedure is pulse heating.

[0147] As an optional implementation, in the preparation of the carbon-supported nanoparticles, a vacuum process is continuously performed during the electrothermal treatment.

[0148] As an optional implementation, in the preparation of the carbon-supported nanoparticles, the pulse heating procedure includes: heating for 0.01 to 1 s, cooling for 0.1 to 5 s, and the peak heating temperature is 300 to 1300 ℃.

[0149] As an optional implementation, in the preparation of the carbon-supported nanoparticles, the particle size of the nanoparticles in the carbon-supported nanoparticles is less than 50 nm, for example, it can be 50 nm, 45 nm, 40 nm, 35 nm, 30 nm, 25 nm, 20 nm, 15 nm, 10 nm, 5 nm, etc.

[0150] In a preferred embodiment, the resistance heating material used for the electrothermal treatment in the preparation of the carbon-supported nanoparticles is a mesh metal.

[0151] It should be noted that, in the embodiments of the present invention for preparing nanoparticles, a mesh metal is preferred, which enables the powder to be transferred from the heat source in a timely manner by falling off, thus avoiding sintering.

[0152] In a preferred embodiment, the mesh metal is a mesh high-melting-point metal, such as any one or a combination of at least two of copper, tungsten, nickel, iron, and molybdenum.

[0153] It should be noted that in the preparation of the carbon-loaded nanoparticles, a resistance heating material is connected between the two electrodes to form a circuit. When current flows through the resistance heating material, it generates a uniform thermal field. The intermittent heating method effectively limits particle agglomeration. Furthermore, the mesh structure of the resistance heating material also helps to separate and dry the sample, preventing further sintering. The formation of nanoparticles can be confirmed by scanning electron microscopy.

[0154] Fifthly, the present invention provides a method for gas synthesis, the gas synthesis comprising: Porous carbon and water are mixed to obtain an aqueous dispersion of porous carbon; the aqueous dispersion of porous carbon is then subjected to freezing treatment, vacuum treatment and electric heating treatment in sequence to obtain carbon monoxide and hydrogen.

[0155] As an optional implementation, the gas synthesis method includes the following steps: the method is based on a phase diagram ( Figure 1 The path shown is as follows: Specific operation: Immerse the reactants in water and freeze them in a low-temperature environment, such as by using a refrigerator, cold trap, or liquid nitrogen for cooling; start the vacuum pump device; apply a suitable current through the power supply device to rapidly raise the temperature of the resistance heating material, driving the solid water to sublimate and react with the reactants at a high temperature to generate chemicals.

[0156] As an optional implementation, in the preparation of carbon monoxide and hydrogen, the mass ratio of porous carbon to water is 1:(1~20), for example, it can be 1:1, 1:2, 1:4, 1:6, 1:8, 1:10, 1:12, 1:14, 1:16, 1:18, 1:20, etc.

[0157] As an optional implementation, in the preparation of carbon monoxide and hydrogen, the freezing temperature is -20~0 ℃, for example, it can be -20 ℃, -18 ℃, -16 ℃, -14 ℃, -12 ℃, -10 ℃, -8 ℃, -6 ℃, -4 ℃, -2 ℃, 0 ℃, etc.

[0158] As an optional implementation, in the preparation of carbon monoxide and hydrogen, the pressure of the vacuum treatment is below 10 Pa, for example, it can be 10 Pa, 9 Pa, 8 Pa, 7 Pa, 6 Pa, 5 Pa, 4 Pa, 3 Pa, 2 Pa, 1 Pa, 0.5 Pa, 0.1 Pa, etc.

[0159] As an optional implementation, in the preparation of carbon monoxide and hydrogen, the electric heating treatment is performed by Joule heating.

[0160] As an optional implementation, in the preparation of carbon monoxide and hydrogen, the electric heating process is a continuous heating procedure.

[0161] As an optional implementation, in the preparation of carbon monoxide and hydrogen, a vacuum process is continuously performed during the electrothermal treatment.

[0162] As an optional implementation, the continuous heating temperature is 350~900 ℃, for example, it can be 350 ℃, 400 ℃, 450 ℃, 500 ℃, 550 ℃, 600 ℃, 650 ℃, 700 ℃, 750 ℃, 800 ℃, 850 ℃, 900 ℃, etc., and the continuous heating time is 1~10 min, for example, it can be 1 min, 2 min, 3 min, 4 min, 5 min, 6 min, 7 min, 8 min, 9 min, 10 min, etc.

[0163] As an optional implementation, the molar ratio of hydrogen to carbon monoxide is (1~1.2):1, for example, it can be 1:1, 1.02:1, 1.04:1, 1.05:1, 1.06:1, 1.1:1, 1.12:1, 1.15:1, 1.16:1, 1.18:1, 1.2:1, etc.

[0164] In a preferred embodiment, in the preparation of carbon monoxide and hydrogen, the resistance heating material used for the electric heating treatment is a carbon felt-like material with a slightly higher resistance.

[0165] It should be noted that, in the gas-generating embodiments of the present invention, materials with slightly higher resistance, such as carbon felt, are preferred. These materials are advantageous for achieving rapid temperature rise with lower current input, thereby reducing drying time and costs.

[0166] Sixthly, the present invention provides a method for modifying the surface oxygen functional groups of graphene oxide, the method comprising: Graphene oxide and water are mixed to obtain an aqueous dispersion of graphene oxide; the aqueous dispersion of graphene oxide is subjected to freezing treatment, vacuum treatment and electric heating treatment in sequence to reduce the graphene oxide and obtain graphene oxide modified with surface oxygen functional groups.

[0167] As an optional implementation, the method for modifying the surface oxygen functional groups of graphene oxide includes the following steps: This method is based on a phase diagram ( Figure 1The path shown is as follows: Specific operation: Freeze the aqueous dispersion of graphene oxide in a low-temperature environment, such as by using a refrigerator, cold trap or liquid nitrogen cooling; start the vacuum pump device; apply a suitable current through the power supply device to rapidly raise the temperature of the resistance heating material, and remove the sample after completing the surface oxygen functional group modification.

[0168] As an optional implementation, in the preparation of the surface oxygen functional group modified graphene oxide, the mass ratio of graphene oxide to water is 1:(100~300), for example, it can be 1:100, 1:120, 1:140, 1:160, 1:180, 1:200, 1:220, 1:240, 1:260, 1:280, 1:300, etc.

[0169] As an optional implementation, in the preparation of the surface oxygen functional group modified graphene oxide, the freezing temperature is -30 to -10 ℃, for example, it can be -30 ℃, -28 ℃, -26 ℃, -24 ℃, -22 ℃, -20 ℃, -18 ℃, -16 ℃, -14 ℃, -12 ℃, -10 ℃, etc.

[0170] As an optional implementation, in the preparation of the surface oxygen functional group modified graphene oxide, the pressure of the vacuum treatment is below 10 Pa, for example, it can be 10 Pa, 9 Pa, 8 Pa, 7 Pa, 6 Pa, 5 Pa, 4 Pa, 3 Pa, 2 Pa, 1 Pa, 0.5 Pa, 0.1 Pa, etc.

[0171] As an optional implementation, in the preparation of the surface oxygen functional group modified graphene oxide, the electrothermal treatment is performed by Joule heating.

[0172] As an optional implementation, in the preparation of the surface oxygen functional group modified graphene oxide, the electrothermal treatment process is continuous heating.

[0173] As an optional implementation, in the preparation of the surface oxygen functional group modified graphene oxide, a vacuum process is continuously performed during the electrothermal treatment.

[0174] As an optional implementation, in the preparation of the surface oxygen functional group modified graphene oxide, the continuous heating temperature is 400~700 ℃, for example, it can be 400 ℃, 450 ℃, 500 ℃, 550 ℃, 600 ℃, 650 ℃, 700 ℃, etc., and the continuous heating time is 1~20 min, for example, it can be 1 min, 2 min, 4 min, 6 min, 8 min, 10 min, 12 min, 14 min, 16 min, 18 min, 20 min, etc.

[0175] As an optional implementation, in the preparation of the surface oxygen functional group modified graphene oxide, the content of oxygen-containing functional groups in the surface oxygen functional group modified graphene oxide is reduced by 60-80% compared with the content of oxygen-containing functional groups in the untreated graphene oxide, for example, it can be 60%, 62%, 64%, 66%, 68%, 70%, 72%, 74%, 76%, 78%, 80%, etc.

[0176] It should be noted that, similarly, the resistance heating material is connected between the two electrodes to form a circuit. When current flows through the resistance heating material, it generates a uniform thermal field. The temperature of the thermal field can be flexibly adjusted according to the input current. Since different oxygen-containing functional groups have different decomposition and desorption temperatures, adjusting the appropriate temperature can promote the desorption of functional groups. The present invention uses X-ray photoelectron spectroscopy to detect the surface functional groups of the graphene processed in the embodiments, demonstrating that the dried graphene produced by this method has a lower content of oxygen functional groups than the raw material.

[0177] In a preferred embodiment, in the preparation of the surface oxygen functional group modified graphene oxide, the resistance heating material for the electrothermal treatment is a carbon felt-like material with a slightly higher resistance.

[0178] It should be noted that in the embodiments of surface oxygen functional group modification, the present invention preferably uses materials with slightly higher resistance, such as carbon felt. Such materials are beneficial for achieving rapid temperature rise with lower current input, thereby reducing drying time and cost.

[0179] In a seventh aspect, the present invention provides a method for drying an aerogel, the method comprising: The hydrogel or dispersion is subjected to freezing, vacuuming and electric heating in sequence to obtain a dry aerogel; wherein the dry aerogel includes dry graphene aerogel or dry MXene aerogel.

[0180] As an optional implementation, the drying method of the graphene aerogel includes the following steps: the method is based on a phase diagram ( Figure 1The path shown is as follows: Specific operation: Prepare hydrogel and freeze the hydrogel in a low-temperature environment, such as by using a refrigerator, cold trap or liquid nitrogen cooling; start the vacuum pump device; apply a suitable current through the power supply device to make the temperature of the resistance heating material rise rapidly, and take out the sample after drying is completed.

[0181] As an optional implementation, the drying method of the MXene aerogel includes the following steps: the method is based on a phase diagram ( Figure 1 The path shown is as follows: Specific operation: Prepare an aqueous solution of MXene and freeze the aqueous solution in a low-temperature environment, such as by using a refrigerator, cold trap or liquid nitrogen cooling; start the vacuum pump device; apply a suitable current through the power supply device to make the temperature of the resistance heating material rise rapidly, and take out the sample after drying is completed.

[0182] It should be noted that MXene is a two-dimensional inorganic compound material, typically composed of transition metal carbides, nitrides, or carbonitrides.

[0183] As an optional implementation, the freezing temperature is -30 to -10 ℃, for example, it can be -30 ℃, -28 ℃, -26 ℃, -24 ℃, -22 ℃, -20 ℃, -18 ℃, -16 ℃, -14 ℃, -12 ℃, -10 ℃, etc.

[0184] As an optional implementation, the pressure of the vacuuming process is below 10 Pa, for example, it can be 10 Pa, 9 Pa, 8 Pa, 7 Pa, 6 Pa, 5 Pa, 4 Pa, 3 Pa, 2 Pa, 1 Pa, 0.5 Pa, 0.1 Pa, etc.

[0185] As an optional implementation, the dried graphene aerogel or dried MXene aerogel is prepared by Joule heating.

[0186] As an optional implementation, the dried graphene aerogel or dried MXene aerogel is prepared, and the electrothermal treatment procedure is continuous heating.

[0187] As an optional implementation, the dried graphene aerogel or dried MXene aerogel is prepared, and vacuum treatment is continuously performed during the electrothermal treatment.

[0188] As an optional implementation, when the dried aerogel is dried graphene aerogel, the continuous heating temperature is 100~500 ℃, for example, it can be 100 ℃, 150 ℃, 200 ℃, 250 ℃, 300 ℃, 350 ℃, 400 ℃, 450 ℃, 500 ℃, etc., and the continuous heating time is 8~60 min, for example, it can be 8 min, 10 min, 15 min, 20 min, 25 min, 30 min, 35 min, 40 min, 45 min, 50 min, 55 min, 60 min, etc.

[0189] As an optional implementation, when the dried aerogel is a dried MXene aerogel, the continuous heating temperature is 70~120℃, for example, it can be 70℃, 75℃, 80℃, 85℃, 90℃, 95℃, 100℃, 105℃, 110℃, 115℃, 120℃, etc., and the continuous heating time is 8~60 min, for example, it can be 8 min, 10 min, 15 min, 20 min, 25 min, 30 min, 35 min, 40 min, 45 min, 50 min, 55 min, 60 min, etc.

[0190] As an optional implementation, the hydrogel is prepared by the following steps: mixing graphene oxide, a reducing agent and water, and then subjecting the mixture to a hydrothermal reaction to obtain the hydrogel.

[0191] As an optional implementation, in the preparation of the graphene aerogel, the mass ratio of graphene oxide, reducing agent and water is 1:(0.1~1):(100~300); wherein, "0.1~1" can be, for example, 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1, etc.; "100~300" can be, for example, 100, 120, 140, 160, 180, 200, 220, 240, 260, 280, 300, etc.

[0192] As an optional implementation, in the preparation of the graphene aerogel, the reducing agent is ascorbic acid.

[0193] As an optional implementation, in the preparation of the graphene aerogel, the temperature of the hydrothermal reaction is 70~90 ℃, for example, it can be 70 ℃, 72 ℃, 74 ℃, 75 ℃, 76 ℃, 78 ℃, 80 ℃, 82 ℃, 84 ℃, 86 ℃, 88 ℃, 90 ℃, etc., and the hydrothermal reaction time is 12~36 h, for example, it can be 12 h, 14 h, 16 h, 18 h, 20 h, 22 h, 24 h, 26 h, 28 h, 30 h, 32 h, 34 h, 36 h, etc.

[0194] As an optional implementation, in the preparation of the MXene aerogel, the dispersion is prepared by the following steps: mixing MXene and water, and then dispersing by ultrasonication to obtain an MXene dispersion.

[0195] As an optional implementation, in the preparation of the MXene aerogel, the mass ratio of MXene to water is 1:(50~300), for example, it can be 1:50, 1:60, 1:80, 1:100, 1:120, 1:140, 1:160, 1:180, 1:200, 1:220, 1:240, 1:260, 1:280, 1:300, etc.

[0196] As an optional implementation, in the preparation of the graphene aerogel, the porosity of the dried graphene aerogel is above 90%, for example, it can be 90%, 92%, 94%, 95%, 96%, 98%, etc.

[0197] As an optional implementation, the MXene includes any one or a combination of at least two of Ti2C, Ti3C2, V2C, Nb2C, Ta4C3, and Mo2C.

[0198] It should be noted that the resistance heating material is connected between the two electrodes to form a circuit. When current flows through the resistance heating material, it generates a uniform thermal field. The temperature of the thermal field can be flexibly adjusted according to the input current. Because the higher the temperature, the faster the ice sublimation rate, the electrothermal vacuum sublimation method can significantly improve the drying efficiency compared to the traditional freeze-drying process that takes tens of hours. This invention has statistically analyzed the aerogels dried at different temperatures and using different drying methods. After comparison, the electrothermal vacuum sublimation drying method has high efficiency, low volume shrinkage, and faster drying at higher temperatures. Furthermore, the morphology of the graphene aerogels prepared in the embodiments of this invention was observed using scanning electron microscopy (SEM), demonstrating that the graphene aerogels dried by this method have abundant pores.

[0199] In a preferred embodiment, in the preparation of the graphene aerogel, the resistance heating material used for the electrothermal treatment is a carbon felt-like material with a slightly higher resistance.

[0200] It should be noted that in the embodiments of graphene aerogel, the present invention preferably uses materials with slightly higher resistance, such as carbon felt. Such materials are advantageous for achieving rapid temperature rise with lower current input, thereby reducing drying time and cost.

[0201] The present invention will be further illustrated by the following examples. Unless otherwise specified, the materials in the examples are prepared according to existing methods or purchased directly from the market.

[0202] Example 1 This embodiment provides sodium chloride nanoparticles, which are prepared by the following steps: (a) Sodium chloride and water are mixed to obtain an aqueous solution of sodium chloride with a mass fraction of 3 wt%; (b) After placing a 3 wt% sodium chloride aqueous solution in an electrothermal vacuum sublimation material processing device, it was first placed in a low-temperature environment and frozen at 263 K. Then, the vacuum pump device was started to reduce the pressure of the sealed cavity to 10 Pa. Finally, it was maintained at 10 Pa and heated by Joule heating and pulse heating program. The pulsed input current (75 A) was used, the heating was 0.8 s and the cooling was 5.0 s. The peak temperature was 573 K and the total drying time was 5 min. The dried sodium chloride nanoparticles were collected. The method for processing materials based on electrothermal vacuum sublimation is carried out using a device for processing materials based on electrothermal vacuum sublimation. The device includes: a cold trap (which can also be replaced by other refrigeration equipment such as a refrigerator), a vacuum pump, a sealed cavity, a programmable DC power supply, a resistance heating material, and electrodes. The resistance heating material is a mesh of tungsten metal, and the electrodes are made of copper metal.

[0203] Test results: via XRD ( Figure 3 The results analysis showed that the product was sodium chloride crystals, as confirmed by SEM characterization. Figure 4 It can be seen that after treatment by the electrothermal vacuum sublimation device, sodium chloride particles with an average particle size of less than 100 nm are obtained. Figure 5 ).

[0204] Example 2 This embodiment provides porous carbon-supported silicon nanoparticles, which are prepared by the following steps: (a) Micron-sized silicon (particle size of 5 μm) and porous carbon were mixed at a mass ratio of 5:95, deionized water was added, the mass ratio of deionized water to solid powder was 3:1, and the mixture was stirred at 400 rpm for 1 h to obtain a mixed solution. (b) After placing the mixed solution in the material processing device of electrothermal vacuum sublimation, it is first placed in a low temperature environment and frozen at 263 K. Then, the vacuum pump device is started to reduce the pressure of the sealed cavity to 10 Pa. Finally, it is maintained at 10 Pa and heated by Joule heating and pulse heating program. The pulse input current (130A) is used, the heating is 0.2 s and the cooling is 1.0 s. The peak temperature is 1400 K and the total drying time is 5 min. The dried porous carbon powder loaded with nano-silicon is collected. The method for processing materials based on electrothermal vacuum sublimation is carried out using a device for processing materials based on electrothermal vacuum sublimation. The device includes: a cold trap (which can also be replaced by other refrigeration equipment such as a refrigerator), a vacuum pump, a sealed cavity, a programmable DC power supply, a resistance heating material, and electrodes. The resistance heating material is a mesh of tungsten metal, and the electrodes are made of copper metal.

[0205] Test results: Characterized by XRD ( Figure 6 ) and SEM characterization ( Figure 7 As can be seen, after being processed by the electrothermal vacuum upgrading device, the micron-sized silicon in the raw material is dispersed into nano-sized silicon particles and loaded onto the porous carbon surface; wherein, the particle size of the nano-sized silicon in the porous carbon powder loaded with nano-sized silicon is 20 nm.

[0206] Example 3 This embodiment provides a graphene oxide-supported platinum nanoparticle, which is prepared by the following steps: (a) Platinum chloride (particle size 50 μm) and graphene oxide were mixed at a mass ratio of 3:97, deionized water was added, the mass ratio of deionized water to solid powder was 3:1, and the mixture was stirred at 400 rpm for 1 h to obtain a mixed solution. (b) After placing the mixed solution in the material processing device of electrothermal vacuum sublimation, it is first placed in a low temperature environment and frozen at 263 K. Then, the vacuum pump device is started to reduce the pressure of the sealed cavity to 10 Pa. Finally, it is maintained at 10 Pa and heated by Joule heating and pulse heating program. The pulse input current (80 A) is used, the heating is 0.8 s and the cooling is 5.0 s. The peak temperature is 773 K and the total drying time is 5 min. The dried graphene powder loaded with platinum nanoparticles is collected. The material processing method based on electrothermal vacuum sublimation is performed using a material processing device based on electrothermal vacuum sublimation; the device includes: a cold trap (which can also be replaced by a refrigerator or other refrigeration equipment), a vacuum pump, a sealed cavity, a programmable DC power supply, a resistance heating material, and electrodes; the resistance heating material is a mesh of tungsten metal, and the electrodes are copper metal.

[0207] Test results: Characterized by XRD ( Figure 8 ) and SEM characterization ( Figure 9 As can be seen, after being processed by the electrothermal vacuum upgrading device, the platinum chloride in the raw material is converted into platinum nanoparticles dispersed on the graphene surface; wherein, the particle size of the platinum particles in the graphene powder loaded with platinum nanoparticles is 20 nm.

[0208] Example 4 This embodiment provides nickel nanoparticles supported on graphene oxide, which are prepared by the following steps: (a) Nickel chloride (particle size 50 μm) and graphene oxide were mixed at a mass ratio of 3:97, deionized water was added, the mass ratio of deionized water to solid powder was 3:1, and the mixture was stirred at 400 rpm for 1 h to obtain a mixed solution. (b) After placing the mixed solution in the material processing device of electrothermal vacuum sublimation, it is first placed in a low temperature environment and frozen at 263 K. Then, the vacuum pump device is started to reduce the pressure of the sealed cavity to 10 Pa. Finally, it is maintained at 10 Pa and heated by Joule heating and pulse heating program. The pulse input current (90 A) is used, the heating is 0.8 s and the cooling is 5.0 s. The peak temperature is 1073 K and the total drying time is 5 min. The dried graphene powder loaded with nano-nickel is collected. The method for processing materials based on electrothermal vacuum sublimation is carried out using a device for processing materials based on electrothermal vacuum sublimation. The device includes: a cold trap (which can also be replaced by other refrigeration equipment such as a refrigerator), a vacuum pump, a sealed cavity, a programmable DC power supply, a resistance heating material, and electrodes. The resistance heating material is a mesh of tungsten metal, and the electrodes are made of copper metal.

[0209] Test results: Characterized by XRD ( Figure 10 ) and TEM characterization ( Figure 11 As can be seen, after being processed by the electrothermal vacuum upgrading device, the nickel chloride in the raw material is converted into nickel nanoparticles dispersed on the graphene surface; wherein, the particle size of the nickel particles in the graphene powder loaded with nickel nanoparticles is 40 nm.

[0210] Example 5 This embodiment provides a method for preparing carbon monoxide and hydrogen, the method comprising the following steps: (a) Porous carbon and deionized water were mixed at a mass ratio of 1:10 and stirred at 400 rpm for 1 h to obtain an aqueous dispersion of porous carbon; (b) After placing the porous carbon aqueous dispersion in an electrothermal vacuum sublimation material processing device, it is first placed in a low-temperature environment and frozen at 263 K. Then, the vacuum pump device is started to reduce the pressure of the sealed cavity to 10 Pa. Finally, it is maintained at 10 Pa and heated by Joule heating and a continuous heating program is used. The current is continuously input (30 A), the peak temperature is 776 K and it is held for 10 min. After the reaction stabilizes, the product gas continuously extracted from the cavity is collected, and the gaseous products are analyzed by gas chromatography after condensation and water removal. The method for processing materials based on electrothermal vacuum sublimation is carried out using a device for processing materials based on electrothermal vacuum sublimation. The device includes: a cold trap (which can also be replaced by other refrigeration equipment such as a refrigerator), a vacuum pump, a sealed cavity, a programmable DC power supply, a resistance heating material, and electrodes. The resistance heating material is carbon felt, and the electrodes are copper metal.

[0211] Test results: Gas chromatography analysis of the collected gas revealed the presence of carbon monoxide and hydrogen. Figure 12 (The ratio of hydrogen to carbon monoxide is 1.12).

[0212] Example 6 This embodiment provides a graphene oxide modified with surface oxygen functional groups, which is prepared by the following steps: (a) Take an aqueous dispersion of graphene oxide with a concentration of 5 mg / mL and ultrasonically disperse it for 30 min to make it more uniformly dispersed. (b) After the ultrasonic graphene oxide aqueous dispersion was placed in the material processing device of electrothermal vacuum sublimation, it was first placed in a low temperature environment and frozen at -20 °C. Then the vacuum pump device was started to reduce the pressure of the sealed cavity to 10 Pa. Finally, it was maintained at 10 Pa and Joule heating was used with a continuous heating program and a continuous input current (30 A) to raise the temperature of the resistance heating material to 776 K and hold for 8 min to obtain graphene oxide modified with surface oxygen functional groups. The method for processing materials based on electrothermal vacuum sublimation is carried out using a device for processing materials based on electrothermal vacuum sublimation. The device includes: a cold trap (which can also be replaced by other refrigeration equipment such as a refrigerator), a vacuum pump, a sealed cavity, a programmable DC power supply, a resistance heating material, and electrodes. The resistance heating material is carbon felt, and the electrodes are copper metal.

[0213] Test results: XPS characterization was performed on the raw materials and samples, among which the raw materials ( Figure 13 ) and samples ( Figure 14 The results showed that the oxygen-containing functional groups on its surface were significantly reduced; in particular, the content of oxygen-containing functional groups in the oxygen-containing functional group-modified graphene oxide decreased by 63% compared with the content of oxygen-containing functional groups in the untreated graphene oxide.

[0214] Example 7 This embodiment provides a method for drying graphene aerogel, which includes the following steps: (a) Take an aqueous dispersion of graphene oxide with a concentration of 5 mg / mL, add ascorbic acid to it, and the mass ratio of ascorbic acid to the solution is (1:300); after the ascorbic acid and graphene oxide solution are mixed evenly, place them in a hydrothermal reactor and react at 80 °C for 24 h. After the reaction is complete, take out the hydrogel and soak it in deionized water for 4 h to replace the internal liquid to obtain graphene hydrogel. (b) After placing the graphene hydrogel in the electrothermal vacuum sublimation material processing device, it is first placed in a low temperature environment and frozen at -20 ℃ for 18 h. Then, the vacuum pump device is started to reduce the pressure of the sealed cavity to 10 Pa. Finally, it is maintained at 10 Pa and a Joule heating method and a continuous heating program are used. The current is continuously input (30 A) to raise the temperature of the resistance heating material to 776 K and hold for 8 min to obtain dry graphene aerogel. The method for processing materials based on electrothermal vacuum sublimation is carried out using a device for processing materials based on electrothermal vacuum sublimation. The device includes: a cold trap (which can also be replaced by other refrigeration equipment such as a refrigerator), a vacuum pump, a sealed cavity, a programmable DC power supply, a resistance heating material, and electrodes. The resistance heating material is carbon felt, and the electrodes are copper metal.

[0215] Test results: SEM characterization of the samples ( Figure 15 This demonstrates that it has abundant pores; wherein, the porosity of the graphene aerogel is 90%.

[0216] Example 8 This embodiment provides a method for drying graphene aerogel. The only difference from Example 7 is that drying is performed at 723K for 10 minutes. After the moisture is completely removed, the drying is stopped and the sample is taken out. Other settings are the same as in Example 7.

[0217] Example 9 This embodiment provides a method for drying graphene aerogel. The only difference from Example 7 is that drying is performed at 593K for 21 minutes. After the moisture is completely removed, the drying is stopped and the sample is taken out. Other settings are the same as in Example 7.

[0218] Example 10 This embodiment provides a drying method for graphene aerogel, which differs from Example 7 only in that it uses 388K for drying, maintains the temperature for 86 minutes, stops drying after the moisture is completely removed, and takes out the sample. Other settings are the same as in Example 7.

[0219] Example 11 This embodiment provides a drying method for graphene aerogel, which differs from Example 7 only in that it uses 298K for drying, maintains the temperature for 660 min, stops drying after all moisture is removed, and takes out the sample. Other settings are the same as in Example 7.

[0220] Example 12 This embodiment provides a method for drying MXene aerogel, which includes the following steps: (a) Take an aqueous dispersion of Ti3C2 with a concentration of 15 mg / mL and ultrasonically disperse it for 60 min.

[0221] (b) After placing the graphene hydrogel in the electrothermal vacuum sublimation material processing device, it is first placed in a low temperature environment and frozen at -20 ℃ for 18 h. Then, the vacuum pump device is started to reduce the pressure of the sealed cavity to 10 Pa. Finally, it is maintained at 10 Pa and a Joule heating method and a continuous heating program are used. The current is continuously input (10 A) to raise the temperature of the resistance heating material to 370 K and hold for 20 min to obtain dry MXene aerogel. The method for processing materials based on electrothermal vacuum sublimation is carried out using a device for processing materials based on electrothermal vacuum sublimation. The device includes: a cold trap (which can also be replaced by other refrigeration equipment such as a refrigerator), a vacuum pump, a sealed cavity, a programmable DC power supply, a resistance heating material, and electrodes. The resistance heating material is carbon felt, and the electrodes are copper metal.

[0222] Test results: SEM characterization of the samples ( Figure 16The XRD results show that the method does not destroy its structure to generate carbides, and the EDS results show that the elements are evenly distributed.

[0223] Comparative Example 1 This comparative example provides a method for drying sodium chloride, the drying method comprising the following steps: (a) Sodium chloride and water are mixed to obtain an aqueous solution of sodium chloride with a mass fraction of 3 wt%; (b) A 3 wt% aqueous solution of sodium chloride was dried under normal pressure in a forced-air drying oven at a temperature of 60 °C for 45 min to obtain sodium chloride granules.

[0224] Comparative Example 2 This comparative example provides a method for drying sodium chloride, the drying method comprising the following steps: (a) Sodium chloride and water are mixed to obtain an aqueous solution of sodium chloride with a mass fraction of 3 wt%; (b) A 3 wt% aqueous solution of sodium chloride was freeze-dried at -56 °C for 90 min to obtain sodium chloride particles.

[0225] Comparative Example 3 This comparative example provides a method for drying graphene aerogel, the drying method comprising the following steps: (a) Take an aqueous dispersion of graphene oxide with a concentration of 5 mg / mL, add ascorbic acid to it, and the mass ratio of ascorbic acid to the solution is (1:300); after the ascorbic acid and graphene oxide solution are mixed evenly, place them in a hydrothermal reactor and react at 80 °C for 24 h. After the reaction is complete, take out the hydrogel and soak it in deionized water for 4 h to replace the internal liquid to obtain graphene hydrogel. (b) The graphene hydrogel was freeze-dried at a temperature of -56 °C for 2200 min to obtain a dried graphene aerogel.

[0226] Comparative Example 4 This comparative example provides a method for drying graphene aerogel, the drying method comprising the following steps: (a) Take an aqueous dispersion of graphene oxide with a concentration of 5 mg / mL, add ascorbic acid to it, and the mass ratio of ascorbic acid to the solution is (1:300); after the ascorbic acid and graphene oxide solution are mixed evenly, place them in a hydrothermal reactor and react at 80 °C for 24 h. After the reaction is complete, take out the hydrogel and soak it in deionized water for 4 h to replace the internal liquid to obtain graphene hydrogel. (b) The graphene hydrogel was dried by air drying at a temperature of 60 °C, an air velocity of 1.5 m / s, and a drying time of 630 min to obtain dried graphene aerogel.

[0227] Comparative Example 5 This comparative example provides a porous carbon-supported silicon particle, which differs from Example 2 only in that it does not involve freezing, but directly starts the vacuum pump device and uses Joule heating for drying. All other settings are the same as in Example 2.

[0228] Comparative Example 6 This comparative example provides a porous carbon-supported silicon particle, which differs from Example 2 only in that the vacuum pump device is not started, and after freezing, it is dried by Joule heating under normal pressure (argon gas). Other settings are the same as in Example 2.

[0229] Comparative Example 7 This comparative example provides a porous carbon-supported silicon particle, which differs from Example 2 only in that it does not use Joule heating. Instead, it is first frozen and then dried in an oven at 100 °C under continuous vacuum. All other settings are the same as in Example 2.

[0230] Test Example 1 Test samples: Sodium chloride nanoparticles provided in Example 1 and sodium chloride particles provided in Comparative Examples 1 and 2; The test results are shown in Table 1 below: Table 1

[0231] As shown in Table 1, the electrothermal vacuum sublimation apparatus can effectively prepare nano-sized sodium chloride particles. Overall, atmospheric pressure drying yields the largest sodium chloride particle size, reaching 2 mm, while the particle sizes obtained by electrothermal vacuum sublimation drying and freeze drying are very close. Furthermore, electrothermal vacuum sublimation drying significantly shortens the drying time and improves production efficiency. This method achieves rapid drying while preventing nanoparticle agglomeration.

[0232] Test Example 2 Test samples: graphene aerogel provided in Example 7 and graphene aerogel provided in Comparative Examples 3-4; The test results are shown in Table 2 below: Table 2

[0233] Table 2 shows that the electrothermal vacuum sublimation drying method used in the examples has significant advantages in terms of drying time and volume shrinkage rate of the graphene aerogel. Specifically, electrothermal vacuum sublimation drying can shorten the drying time of graphene aerogel to 8 minutes, while freeze-drying and forced-air drying require 630 minutes. Furthermore, electrothermal vacuum sublimation drying can effectively suppress volume shrinkage, with a volume shrinkage rate of 6.6%, close to the level of freeze-drying. For the same sample, atmospheric pressure drying is accompanied by an extremely high volume shrinkage rate, leading to complete deformation. Finally, electrothermal vacuum sublimation drying has significant energy-saving effects; drying the same size sample consumes only 0.6% of the energy of freeze-drying.

[0234] Test Example 3 Test samples: Graphene aerogels provided in Examples 7-11; The test results are shown in Table 3 below: Table 3

[0235] As shown in Table 3, different temperatures significantly affect the drying rate, with the general trend being that the higher the temperature, the faster the drying rate. Furthermore, the electrothermal vacuum ascent drying method maintains a low volume shrinkage rate at different temperatures, demonstrating its excellent drying capability for graphene aerogels.

[0236] Test Example 4 Test samples: Graphene aerogel and MXene aerogel provided in Examples 7 and 12; The test results are shown in Table 4 below: Table 4

[0237] As shown in Table 4, this drying method is applicable to both MXene aerogel and graphene aerogel, and can maintain an extremely low volume shrinkage rate while significantly increasing the drying rate.

[0238] Test Example 5 Test samples: porous carbon-supported silicon nanoparticles provided in Example 2, and porous carbon-supported silicon nanoparticles provided in Comparative Examples 5-7; The test results are shown in Table 5 below: Table 5

[0239] As shown in Table 5, Comparative Examples 5 and 6 exhibit slight agglomeration and incomplete nano-sizing, with average particle sizes larger than Example 2. The main reason is that Comparative Example 5 lacked a freezing process, rendering the ice ineffective in preventing nanoparticle migration. While Comparative Example 6 included a freezing process, it failed to maintain a low-pressure environment, causing the ice to melt and again failing to prevent nanoparticle migration. Therefore, both examples had larger particle sizes than Example 2. Comparative Example 7 revealed that silicon could not be nano-sized using a vacuum oven at 100°C. This is partly due to the low upper temperature limit of the vacuum oven, far below the melting or sublimation temperature of silicon. Since the diffusion rate of solids is much lower than that of liquids and gases, it is difficult to achieve dispersion in a short time. Furthermore, the slow heating and cooling rate of the oven prevents the kinetic control of nanoparticles achieved through Joule heating. Even if the temperature reaches the melting point of silicon, liquid silicon will undergo Oswald ripening to form micron-sized silicon.

[0240] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for processing materials based on electrothermal vacuum sublimation, characterized in that, The processing method includes: The material containing water is subjected to freezing, vacuuming, and electric heating in sequence to obtain the processed material.

2. The method for processing materials based on electrothermal vacuum sublimation according to claim 1, characterized in that, The freezing process includes: freezing the water-containing material in a low-temperature environment to obtain an ice-containing material; Preferably, the freezing temperature is -70 to 0 °C.

3. The method for processing materials based on electrothermal vacuum sublimation according to claim 1, characterized in that, The vacuuming process includes: drawing the cavity of the device into a vacuum; Preferably, the pressure of the vacuuming process is below 660 Pa.

4. The method for processing materials based on electrothermal vacuum sublimation according to claim 1, characterized in that, The electroheating treatment includes: applying current through a power supply device to raise the temperature of the resistance heating material, performing electroheating treatment, and obtaining the treated material; Preferably, the electric heating treatment method includes any one or a combination of at least two of Joule heating, induction heating, infrared heating, and laser heating, with Joule heating being the preferred method. Preferably, the electric heating process includes continuous heating and / or pulse heating; Preferably, the temperature of the electric heating treatment is 25~1500 ℃, the heating rate of the electric heating treatment is 10~1000 ℃ / s, and the time of the electric heating treatment is 0.01 s~100 min.

5. The application of a material processing method based on electrothermal vacuum sublimation according to any one of claims 1 to 4 in nanoparticle preparation, gas synthesis, material surface modification, and aerogel drying.

6. A method for preparing nanoparticles, characterized in that, The method for preparing the nanoparticles includes: The precursor and water are mixed to obtain an aqueous solution of the precursor; the aqueous solution of the precursor is subjected to freezing treatment, vacuum treatment and electric heating treatment in sequence to obtain nanoparticles of the precursor. Preferably, the precursor includes any one or a combination of at least two of sodium chloride, potassium chloride, calcium chloride, sodium nitrate, potassium nitrate, sodium sulfate, and potassium sulfate; Preferably, the particle size of the precursor is 1~100 μm; Preferably, the precursor in the aqueous solution contains 0.1-5 wt% of the precursor. Preferably, the freezing temperature is -100~0℃; Preferably, the pressure of the vacuuming process is below 10 Pa; Preferably, the electric heating treatment is Joule heating; the electric heating treatment procedure is pulse heating; and a vacuum process is continuously performed during the electric heating treatment. Preferably, the pulse heating program includes: heating for 0.01~1 s, cooling for 0.1~10 s, and the peak heating temperature is 100~450 ℃; Preferably, the average particle size of the precursor nanoparticles is less than 100 nm.

7. A method for preparing carbon-supported nanoparticles, characterized in that, The method for preparing the carbon-supported nanoparticles includes: A precursor, a carbon support, and water are mixed to obtain a mixed solution; the mixed solution is then subjected to freezing, vacuuming, and electrothermal treatment in sequence to obtain carbon-loaded nanoparticles. Preferably, the precursor comprises silicon particles and / or a metal source; Preferably, the metal source includes any one or a combination of at least two of the following: platinum chloride, nickel chloride, copper chloride, ferric chloride, cobalt chloride, copper nitrate, nickel nitrate, copper sulfate, and nickel sulfate. Preferably, the silicon particles have a particle size of 1~5 μm; Preferably, the particle size of the metal source is 1~100 μm; Preferably, the carbon support comprises any one or a combination of at least two of porous carbon, graphene oxide, graphene film, carbon fiber, carbon cloth, and carbon felt. Preferably, the mass ratio of the precursor to the carbon support is (1~10):(99~90); Preferably, the mass ratio of water to solid material is (1~10):1; Preferably, the freezing temperature is -20 to 0 °C; Preferably, the pressure of the vacuuming process is below 10 Pa; Preferably, the electric heating treatment is Joule heating; the electric heating treatment procedure is pulse heating; and a vacuum process is continuously performed during the electric heating treatment. Preferably, the pulse heating program includes: heating for 0.01~1 s, cooling for 0.1~5 s, and the peak heating temperature is 300~1300 ℃; Preferably, the particle size of the carbon-supported nanoparticles is less than 50 nm.

8. A method for gas synthesis, characterized in that, The gas synthesis includes: Porous carbon and water are mixed to obtain an aqueous dispersion of porous carbon; the aqueous dispersion of porous carbon is then subjected to freezing treatment, vacuum treatment and electric heating treatment in sequence to obtain carbon monoxide and hydrogen. Preferably, the mass ratio of the porous carbon to water is 1:(1~20); Preferably, the freezing temperature is -20 to 0 °C; Preferably, the pressure of the vacuuming process is below 10 Pa; Preferably, the electric heating treatment is Joule heating; the electric heating treatment procedure is continuous heating; and a vacuum process is continuously performed during the electric heating treatment. Preferably, the continuous heating temperature is 350~900 ℃, and the continuous heating time is 1~10 min; Preferably, the molar ratio of hydrogen to carbon monoxide is (1~1.2):

1.

9. A method for modifying the surface oxygen functional groups of graphene oxide, characterized in that, The method for modifying the surface oxygen functional groups of the graphene oxide includes: Graphene oxide and water are mixed to obtain an aqueous dispersion of graphene oxide; the aqueous dispersion of graphene oxide is subjected to freezing treatment, vacuum treatment and electric heating treatment in sequence to reduce the graphene oxide and obtain graphene oxide modified with surface oxygen functional groups. Preferably, the mass ratio of graphene oxide to water is 1:(100~300); Preferably, the freezing temperature is -30 to -10 °C; Preferably, the pressure of the vacuuming process is below 10 Pa; Preferably, the electric heating treatment is Joule heating; the electric heating treatment procedure is continuous heating; and a vacuum process is continuously performed during the electric heating treatment. Preferably, the continuous heating temperature is 400~700 ℃, and the continuous heating time is 1~20 min; Preferably, the content of oxygen-containing functional groups in the surface oxygen-functionalized graphene oxide is reduced by 60-80% compared to the content of oxygen-containing functional groups in untreated graphene oxide.

10. A method for drying aerogel, characterized in that, The drying method for the aerogel includes: The hydrogel or dispersion is subjected to freezing, vacuuming and electric heating in sequence to obtain a dry aerogel; wherein the dry aerogel includes dry graphene aerogel or dry MXene aerogel. Preferably, the freezing temperature is -30 to -10 °C; Preferably, the pressure of the vacuuming process is below 10 Pa; Preferably, the electric heating treatment is Joule heating; the electric heating treatment procedure is continuous heating; and a vacuum process is continuously performed during the electric heating treatment. Preferably, when the dried aerogel is dried graphene aerogel, the continuous heating temperature is 100~500℃ and the continuous heating time is 8~60 min; Preferably, when the dried aerogel is a dried MXene aerogel, the continuous heating temperature is 70~120 °C and the continuous heating time is 8~60 min; Preferably, the hydrogel is prepared by the following steps: mixing graphene oxide, a reducing agent and water, and then subjecting the mixture to a hydrothermal reaction to obtain the hydrogel; Preferably, the mass ratio of graphene oxide, reducing agent and water is 1:(0.1~1):(100~300); Preferably, the reducing agent is ascorbic acid; Preferably, the hydrothermal reaction temperature is 70~90 ℃, and the hydrothermal reaction time is 12~36 h; Preferably, the dispersion is prepared by the following steps: mixing MXene and water, and then dispersing by ultrasonication to obtain an MXene dispersion; Preferably, the mass ratio of MXene to water is 1:(50~300); Preferably, the porosity of the dried graphene aerogel is above 90%; Preferably, the MXene includes any one or a combination of at least two of Ti2C, Ti3C2, V2C, Nb2C, Ta4C3, and Mo2C.

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