Preparation device, preparation method and application of multi-dimensional high-entropy nano material

Abstract

The invention discloses a preparation device, a preparation method and application of a multi-dimensional high-entropy nano material. The preparation device comprises a process pipe cavity, a plasma generation module, a precursor injection module and an electromagnetic field generation module, the plasma generation module is arranged in the plasma generation area; the precursor injection module comprises an injection pipeline, and a jet orifice of the injection pipeline is arranged in the plasma jet area; the electromagnetic field generation module is arranged in the plasma spraying area. According to the invention, the precursor is directly injected into the plasma injection region and does not pass through the plasma generation region, so that interference and damage to plasma excitation of the plasma generation region caused by products due to physical and chemical reaction in the plasma generation region are avoided; the external electric field / magnetic field is arranged in the plasma spraying area, so that the complete reaction process of the precursor is completed under the regulation and control action of the electromagnetic field, and the multi-dimensional high-entropy nano material with various morphology selections and stable and controllable morphology can be obtained.

Description

Technical Field

[0001] The present invention relates to the technical field of micro-nano material preparation, and in particular to a preparation device, preparation method and application of a multi-dimensional high-entropy nanomaterial. Background Art

[0002] Thanks to the unique high-entropy effect, hysteresis diffusion effect, lattice distortion effect and cocktail effect, high-entropy nanometal particles and their compounds have many excellent physical, chemical and mechanical properties, such as ultra-high electrochemical activity, extremely low thermal conductivity, adjustable conductivity and semiconductor properties, ultra-high hardness, etc., and have demonstrated excellent performance and broad application prospects in 3D printing, energy storage, catalysis, electronic devices, conductive pastes, thermal insulation coatings and other fields.

[0003] Continuous and controllable preparation in large quantities has become a constraint on the development and application of high-entropy nanomaterials. The current mainstream preparation methods, including mechanical ball milling, electric wire explosion, resistance heating, plasma sputtering, laser induction, sol-gel, spray pyrolysis, freeze-drying and other liquid phase preparation methods, are relatively time-consuming and difficult to achieve stable and continuous large-scale preparation of high-entropy nanomaterials.

[0004] The ultra-high heating temperature (6000-8000K) and continuous jet generation method of the microwave plasma torch make it a very efficient method for preparing high-entropy nanomaterials, and it is promising to achieve high-throughput continuous batch industrial production of high-entropy nanomaterials.

[0005] Elemental composition, elemental ratio, elemental distribution, and morphology are several factors that determine the performance of high-entropy nanomaterials. During the plasma torch preparation of high-entropy nanomaterials, the elemental composition and elemental ratio of the resulting high-entropy nanomaterial can be controlled by varying the elements and their ratios in the precursors. However, this method makes it difficult to control the morphology and elemental distribution of the resulting high-entropy nanomaterials, making it difficult to obtain one-dimensional, two-dimensional, and heterogeneous nanostructures. Therefore, improving plasma torch-based high-entropy nanomaterial preparation methods, introducing new control variables, and achieving effective control over the elemental distribution and morphology of the products have become key issues that need to be addressed in this field. Summary of the Invention

[0006] In view of the shortcomings of the existing technology, the purpose of the present invention is to provide a preparation device, preparation method and application of multi-dimensional high-entropy nanomaterials.

[0007] To achieve the aforementioned object of the invention, the technical solutions adopted by the present invention include:

[0008] In a first aspect, the present invention provides a device for preparing multi-dimensional high-entropy nanomaterials, which includes a process tube cavity extending along a specified direction, a plasma generation module, a precursor injection module, and an electromagnetic field generation module;

[0009] The process tube cavity includes a plasma generation area and a plasma injection area in sequence along the specified direction. The plasma generation module is arranged at the plasma generation area, and is used to form plasma inside the process tube cavity and inject the plasma into the plasma injection area along the specified direction.

[0010] The precursor injection module is used to inject the precursor into the process tube cavity, and includes an injection pipeline, wherein the injection port of the injection pipeline is arranged in the plasma injection area, and the injection direction of the injection port is in the specified direction;

[0011] The electromagnetic field generating module is arranged in the plasma ejection zone, and is used for applying a controllable electric field and / or magnetic field to the plasma ejection zone.

[0012] In a second aspect, the present invention further provides a method for preparing multi-dimensional high-entropy nanomaterials using the above-mentioned preparation device, which comprises:

[0013] Generate plasma from a plasma generating region and eject it into a plasma ejection region along a specified direction;

[0014] Directly injecting a precursor into the plasma injection zone, wherein the precursor has no contact with the plasma in the plasma generating zone, and a physical-chemical reaction is formed in the plasma injection zone under the action of the plasma;

[0015] A controllable electric field and / or magnetic field is simultaneously applied to the plasma injection zone to regulate the physical and chemical reaction.

[0016] In a third aspect, the present invention also provides applications of the multi-dimensional high-entropy nanomaterials prepared by the above preparation method in the fields of energy and catalysis, coatings, electronic devices, and optical devices.

[0017] Based on the above technical solution, compared with the prior art, the beneficial effects of the present invention include at least:

[0018] The preparation device and corresponding preparation method provided by the present invention directly inject the precursor into the plasma injection zone without passing the precursor through the plasma generating zone, thereby avoiding the interference and damage of the plasma excitation in the plasma generating zone caused by the product of the physicochemical reaction in the plasma generating zone, especially avoiding the problem of uncontrollable discharge caused by the formation of deposits in the plasma generating zone and the problem of plasma instability caused by disturbances caused by the evaporation and pyrolysis process of the precursor; by setting an external electric field / magnetic field in the plasma injection zone, the entire reaction process of the precursor is completed under the regulation of the electromagnetic field, and multi-dimensional high-entropy nanomaterials with diverse morphology options and stable and controllable morphology can be obtained.

[0019] The above description is only an overview of the technical solution of the present invention. In order to enable those skilled in the art to more clearly understand the technical means of this application and implement them according to the contents of the specification, the following is an explanation of the preferred embodiments of the present invention with detailed drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 It is a structural schematic diagram of a preparation device provided by a typical embodiment of the present invention;

[0021] Figure 2 is a structural schematic diagram of a preparation device provided by another typical embodiment of the present invention;

[0022] Figure 3 This is an electron microscope image of a high entropy material provided by a typical embodiment of the present invention;

[0023] Figure 4 This is an electron microscope image of a high entropy material provided by a typical comparative example of the present invention;

[0024] Figure 5 This is an electron microscope image of a high entropy material provided by another typical comparative case of the present invention. DETAILED DESCRIPTION

[0025] At present, the technical solution of using plasma to prepare high-entropy alloy nanoparticles has been deeply studied by many researchers, but there are still some problems, such as:

[0026] (1) It is difficult to achieve ultra-high-speed preparation of various conventional and even unconventional high-entropy nanomaterials, including high-entropy alloys, high-entropy oxides, high-entropy nitrides, high-entropy carbides, high-entropy borides, etc. containing conventional low-melting-point elements and unconventional ultra-high-melting-point elements.

[0027] (2) The problem of difficulty in controlling the dimensions and morphological structure of high-speed nanomaterials prepared by plasma torch, as well as the problem of difficulty in controlling the element distribution.

[0028] (3) Conventional plasma reaction preparation methods use process gases to transport precursors, which pass through the plasma generation zone and then enter the plasma injection zone, thereby causing physical and chemical reactions under the action of plasma. However, deposition is very likely to occur in the plasma generation zone, and there is often a large potential difference in the plasma generation zone, which will cause discharge in this area, causing sparks and even burning through the wall of the reaction tube cavity. At the same time, it also has an adverse effect on the stability of subsequent physical and chemical reactions, exacerbating the problem of difficult control of the product morphology.

[0029] (4) In addition, the conventional preparation method mentioned above will also lead to the problem that the precursor gasification and pyrolysis process in the plasma generation area cannot be controlled by the electromagnetic field, and the fluctuations caused by gasification and pyrolysis will also aggravate the instability of the ejected plasma torch.

[0030] Due to various factors, attempts to control product morphology by applying an electromagnetic field to the plasma injection zone in conventional plasma reaction devices have not been successful.

[0031] In view of the shortcomings of the prior art, the inventors of this case, after long-term research and extensive practice, have proposed the technical solution of the present invention. The following will further explain this technical solution, its implementation process and principles.

[0032] In the following description, many specific details are set forth to facilitate a full understanding of the present invention. However, the present invention may also be implemented in other ways different from those described herein. Therefore, the scope of protection of the present invention is not limited to the specific embodiments disclosed below.

[0033] An embodiment of the present invention provides a preparation device for multi-dimensional high-entropy nanomaterials, which includes a process tube cavity extending along a specified direction, a plasma generation module, a precursor injection module and an electromagnetic field generation module; the process tube cavity includes a plasma generation zone and a plasma injection zone in sequence along the specified direction, the plasma generation module is arranged at the plasma generation zone, and is used to form plasma inside the process tube cavity and inject the plasma into the plasma injection zone along the specified direction; the precursor injection module is used to inject the precursor into the process tube cavity, and includes an injection pipeline, the injection port of the injection pipeline is arranged in the plasma injection zone, and the injection direction of the injection port is in the specified direction; the electromagnetic field generation module is arranged in the plasma injection zone, and is used to apply a controllable electric field and / or magnetic field to the plasma injection zone.

[0034] The inventors have observed for a long time that if the precursor is sprayed into or before the plasma generating zone, the precursor will react in the plasma generating zone. This reaction will first lead to the formation of deposits and high-voltage ignition and ablation, which will have a serious impact on the life of the equipment and the sustainability of the preparation. Secondly, since this reaction occurs in the plasma generating zone, it is difficult to set up an additional electromagnetic field generating device in the plasma generating zone because the plasma generating zone requires an excitation source, such as microwave, radio frequency, or high-voltage direct current. Therefore, the electromagnetic field generating device can only be set in the plasma injection zone. This results in the reaction at this stage being unable to be effectively electromagnetically controlled. Finally, the occurrence of this reaction will also cause complex changes in the plasma (for example, a very complex ion atmosphere is generated at this stage, including the original ions, new ions formed by the cracking and excitation of the precursor, and the complex environment generated by the interaction between the original ions and the new ions). As a result, even if a controllable electromagnetic field is applied to the plasma injection zone, the subsequent reaction cannot be stably, effectively, and repeatably controlled, and the goal of controlling the product morphology by the applied electromagnetic field cannot be achieved.

[0035] However, the preparation device provided by the present invention does not make the precursor pass through the plasma generating zone, but directly injects it into the plasma injection zone, avoiding the reaction in the plasma generating zone, thereby circumventing the above-mentioned problem.

[0036] In some embodiments, the injection pipeline extends in the process tube cavity through the plasma generating region to the plasma injection region, and at least the injection pipeline in the plasma generating region is made of insulating material.

[0037] Or in some embodiments, the injection line enters the process tube chamber from the side wall of the plasma spraying zone and turns to extend in the designated direction.

[0038] In some embodiments, the injection pipeline includes a precursor passage at a central axis and a cooling interlayer wrapping the precursor passage, wherein the cooling interlayer is used to circulate a cooling medium.

[0039] In some embodiments, the precursor injection module further includes a precursor pumping unit and a cooling medium pumping unit, wherein the precursor pumping unit is in communication with the precursor passage, and the cooling medium pumping unit is in communication with the cooling interlayer.

[0040] In some embodiments, the electromagnetic field generating module includes an induction coil and / or a field plate; the induction coil surrounds the plasma injection region, and / or the plasma injection region is located between a pair of field plates.

[0041] In some embodiments, the process lumen further includes a lumen inlet and a lumen outlet, and the direction from the lumen inlet to the lumen outlet is the specified direction; the lumen inlet is connected to a process gas pumping module for pumping process gas into the process lumen, and the process gas is excited into a plasma state after passing through the plasma generating region; the lumen outlet is connected to a collecting device, and the collecting device is used to collect products.

[0042] As a typical example of the above technical solution, a representative embodiment of the present invention takes a plasma torch generator as the core, adds a continuous precursor injection device, and establishes an ultra-high-speed preparation system for high-entropy nanomaterials; the continuous precursor injection device is equipped with a high-temperature resistant injection head, which can be extended from the plasma generating area (microwave resonant cavity, or other plasma excitation source) from top to bottom to the plasma injection area, or through a specially designed reaction tube, the injection head is directly extended from the side into the plasma injection area and then turned to ensure that the precursor is directly injected into the area, avoiding the precursor from entering the plasma generating area (that is, the range affected by the microwave resonant cavity or other plasma excitation source), so as to prevent the precursor from entering the plasma generating area to react and produce metal or carbonaceous materials deposited on the wall of the reaction tube, thereby avoiding continuous ignition and melting of the reaction tube (for example, metal or carbonaceous conductive materials deposited within the resonant cavity will continuously produce ignition, resulting in local ultra-high temperature, melting the quartz tube, and other excitation sources will also have similar phenomena).

[0043] The injector head is typically made of high-temperature resistant materials and has internal water-cooling channels. Cooling water is injected through a separate cooling water circulation system to prevent it from being burned by the high-temperature plasma. The high-temperature resistant injector head, which extends from the plasma generation zone to the plasma injection zone, must be made of non-conductive, high-temperature resistant ceramic to prevent ignition and melting of conductive materials under the influence of high-energy microwaves. The injector head, which extends directly from the plasma injection zone into the plasma, does not have this requirement and can be made of high-temperature resistant ceramic or metal.

[0044] An electromagnetic field generator is installed outside the plasma torch spray area, and the electric field or magnetic field is used to drive the directional movement of ionized atoms in high-energy, high-temperature plasma, thereby controlling the thermal decomposition, nucleation growth and self-assembly process of raw materials of high-entropy nanomaterials, breaking through the dimensional limitations of nanomaterials synthesized by non-equilibrium plasma torch, and preparing one-dimensional nanowires / nanochains or two-dimensional nanosheets, realizing the regulation of element gradient distribution or heterogeneous distribution.

[0045] Specific as Figure 1 and 2 As shown, the specific design of the preparation device provided in the embodiment of the present invention is:

[0046] 1. Install a precursor supply system on the ultra-high-speed continuous preparation system based on a microwave plasma torch. The precursor supply system includes a designed high-temperature resistant injection head, a precursor delivery device, and corresponding delivery pipelines. The precursor delivery device includes pumps suitable for various liquid precursors (syringe pumps, peristaltic pumps, etc.) and feeding devices suitable for powders (screw feeders, powder injection devices, and funnels, etc.). The high-temperature resistant injection head is made of non-conductive and high-temperature resistant material, and has a precursor delivery channel and a cooling water circulation channel inside. The precursor delivery channel is connected to the precursor delivery device through a pipeline, which can achieve continuous delivery of the precursor. The cooling water circulation channel is connected to a separate cooling water circulation machine (cooling water circulation machine 2 in the figure), which forces the temperature to drop by flowing low-temperature cooling water to prevent it from being burned in the high-temperature plasma.

[0047] The length of the high-temperature resistant injection head must be carefully designed so that the end of the injection head can extend into the plasma injection area, but relatively close to the plasma generation area (for example, the extension distance does not exceed 1 / 2 of the plasma injection area). This ensures that the precursor cannot enter the plasma generation area and can pass a relatively long distance in the plasma injection area, ensuring that the precursor can fully react to form high-entropy nanomaterials. Generally, the edge of the plasma generation area at the end of the injection head needs to be 2-5 cm (for example, when using microwave plasma, the distance from the end of the microwave resonant cavity should be maintained at 2-5 cm). This length can vary with the precursor injection speed and gas flow rate. The specific conditions can be determined through experimental conditions and will not be repeated here.

[0048] Taking the microwave plasma device as an example, the ultra-high-speed preparation system based on microwave plasma described above is composed of a microwave power supply, a magnetron head, a resonant cavity, a cooling water circulation machine 1, a quartz tube, a spiral air intake device, a gas flow meter, a gas cylinder, and a gas pipeline. The quartz tube is inserted into the resonant cavity and matched with it. The spiral air intake device, gas flow meter, gas cylinder, and gas pipeline constitute the air intake system.

[0049] The high temperature resistant injection head can be made of alumina ceramics or quartz, or other non-conductive high temperature resistant materials; the high temperature resistant injection head can pass through the microwave resonant cavity (plasma generation area) from top to bottom and enter the plasma injection area, or a special quartz tube can be designed to add a channel in the plasma injection area, thereby extending the injection head into the plasma injection area; the added external field can be a steady electric field, an alternating electric field, a steady magnetic field, an alternating magnetic field, or an electromagnetic field; the steady magnetic field can be generated by an electromagnet or a permanent magnet, and the alternating magnetic field can be generated by changing the current in the electromagnet, or by controlling the motion state of the permanent magnet (the permanent magnet leaves or approaches the microwave plasma torch, rotates the permanent magnet, etc.); the microwave plasma torch used can be changed to radio frequency, etc. A plasma torch or a DC plasma torch can form an ultra-high temperature plasma, and the corresponding power supply can be replaced by a radio frequency power supply, a DC power supply, etc. The metal precursor can be a metal element, an alloy, a metal salt, an oxide, and other compound materials; it can be in the form of a solution or powder, or a rod-shaped block; the solution and powder can be injected into the high-temperature plasma reaction zone by direct free fall or spraying, and the rod-shaped block can enter the high-temperature plasma reaction zone by slowly extending it; the solution conveyor can be a peristaltic pump or a syringe pump, and the injection equipment can be a funnel, an ultrasonic atomizer, or a jet atomizer; the powder conveyor can be a screw feeder or other feeding system, and the injection equipment can be a funnel, a powder sprayer, etc.; the transportation of rod-shaped objects can be carried out by linear motion machinery such as a screw rod. A variety of precursors can be transported separately by constructing multiple transport channels, or they can be mixed and transported together; when preparing pure metal or high-entropy alloy nanoparticles, argon, helium, neon and other gases that do not react with metals can be used as carrier gases; when preparing metal oxides, air or pure oxygen, or argon / oxygen, neon / oxygen, helium / oxygen mixed gases can be used; when preparing nitrides, nitrogen-containing gases such as nitrogen and ammonia can be used; when preparing carbides, carbon-containing gases such as methane, ethane, and ethylene can be used.

[0050] A second aspect of the embodiments of the present invention further provides a method for preparing a multi-dimensional high-entropy nanomaterial using the preparation device provided in any of the above embodiments, which comprises the following steps:

[0051] Generate plasma from a plasma generating region and eject it into a plasma ejection region along a specified direction;

[0052] Directly injecting a precursor into the plasma injection zone, wherein the precursor has no contact with the plasma in the plasma generating zone, and a physical-chemical reaction is formed in the plasma injection zone under the action of the plasma;

[0053] A controllable electric field and / or magnetic field is simultaneously applied to the plasma injection zone to regulate the physical and chemical reaction.

[0054] In some embodiments, the precursor includes any one of a metal element, an alloy, a metal salt, and a metal oxide, or a combination of two or more thereof.

[0055] In some embodiments, the process tube cavity contains a process gas flowing along the specified direction, and the process gas is used to form the plasma; the injection pipeline contains a carrier gas, and the carrier gas is used to transport the precursor.

[0056] In some embodiments, the process gas and / or carrier gas includes any one or a combination of two or more of argon, helium, neon, oxygen, air, nitrogen, ammonia, methane, ethane, and ethylene.

[0057] The typical steps for implementing the above preparation method can be as follows:

[0058] 1. Prepare the precursor solutions or powders of various metal elements and non-metal elements according to the prepared high entropy nanomaterials, mix them and input them into the feeding system;

[0059] 2. Select the gas according to the prepared nanomaterial and deliver it to the ultrasonic torch generator;

[0060] 3. Turn on the chiller 1 to cool down the preparation device to prevent overheating of the microwave power supply, magnetron, microwave plasma torch generator and magnetic field generating device during the preparation process; turn on the cooling water 2 to cool down the injection head to prevent it from overheating and burning;

[0061] 4. Open the gas valve and introduce the carrier gas used in the preparation equipment (argon for high-entropy metal nanoparticles, nitrogen for high-entropy nitrides, methane or other carbon-containing gases for metal carbides, oxygen or air for high-entropy oxides, and mixed gases for mixed products), remove the air in the preparation device, and adjust the gas flow rate to facilitate the generation of a plasma torch;

[0062] 5. Turn on the microwave power supply and start generating microwave plasma;

[0063] 6. Open the feeding system and extend the injection head into the plasma spray area (the solution can be ultrasonically atomized, sprayed, or directly added; the metal powder can be added by powder spraying or funnel) to start the preparation of high entropy nanomaterials;

[0064] 7. Install a spiral coil outside the spray area of ​​the microwave plasma torch and connect it to a power source. Control the spiral coil by inputting current to generate a magnetic field in the high-energy plasma torch. Control the current size and change to control the intensity and alternation of the magnetic field (it can be replaced with a flat electrode + high-voltage power supply to generate an electric field around the plasma torch, and control the voltage size and change to control the intensity and alternation of the electric field), thereby regulating the product morphology and structure and the element distribution therein;

[0065] 8. Collect and summarize the morphology and element distribution of the product under different magnetic field (electric field) parameters and establish a process database;

[0066] 9. According to application requirements, select process parameters, scale up preparation equipment, proportionally control optimal process parameters, expand production, and achieve large-scale batch preparation.

[0067] The embodiments of the present invention also provide applications of the multi-dimensional high-entropy nanomaterials prepared by the above preparation method in the fields of energy and catalysis, coatings, electronic devices, and optical devices.

[0068] Specifically, the regulation of element distribution and morphological structure of various types of high-entropy nanomaterials includes: the regulation of high-entropy nanomaterials required for energy and catalytic applications; the regulation of high-entropy nanomaterials required in the coating field, such as thermal insulation coatings; the regulation of high-entropy nanomaterials required in the electronic device field, such as high dielectric materials; the regulation of high-entropy nanomaterials required in the optical device field, such as light absorption, reflection or transmission materials, etc.

[0069] The technical solution of the present invention is further described in detail below through several embodiments and in conjunction with the accompanying drawings. However, the selected embodiments are only used to illustrate the present invention and are not intended to limit the scope of the present invention.

[0070] Example 1

[0071] This embodiment illustrates the preparation process of graphene-coated FeCoNiMnCr high-entropy nanoparticles using the above-mentioned device, as shown below:

[0072] Turn on cooling water circulation machines 1 and 2 to cool the equipment, and turn on oxygen to fill the reaction area with oxygen at a gas flow rate of 10 L / min;

[0073] Turn on the microwave power supply and ignite to generate microwave plasma (no ignition is required for low pressure). The microwave power is 1800W and the quartz tube is 1 inch in diameter.

[0074] An ethanol solution of Fe, Co, Ni, Mn, and Cr chlorides (concentration 1 mol / L) was placed in the precursor reservoir, and the injection head was inserted from top to bottom through the plasma generation zone into the plasma injection zone. An alternating electromagnetic field (current 2 A, frequency 1 kHz) was generated by combining an electromagnetic coil with an alternating current.

[0075] After the microwave plasma torch stabilizes, the peristaltic pump is turned on to deliver the precursor to the ultrasonic atomizer at a rate of 1 mL / min. At this point, a chemical reaction occurs within the influence of the magnetic field, altering the nucleation and growth process of the metal elements, thereby promoting their mutual dissolution and forming a graphene-coated FeCoNiMnCr high-entropy nanostructure with uniformly mixed elements.

[0076] The product was collected and tested to obtain nano- and submicron-sized graphene-coated FeCoNiMnCr high-entropy nanoparticles. Figure 3 As shown, graphene-coated FeCoNiMnCr high-entropy nanoparticles can be observed, and the five metal elements are evenly mixed.

[0077] Comparative Example 1-1

[0078] This comparative example is substantially the same as Example 1, with the difference being that the injection head is inserted from above, but the insertion is shallow, and does not enter the plasma injection zone or the plasma generation zone. The precursor will be transported by the process gas through the plasma generation zone and the plasma injection zone.

[0079] After a period of operation, the quartz tube wall in the resonant cavity (i.e., the plasma generation area) turned black, with large amounts of carbon and metallic materials deposited. Under the action of microwaves, it continuously ignited, producing intense sparks. After about a minute, both the sparks and the plasma disappeared. Inspection confirmed that the quartz tube had melted, creating a hole about 5mm in diameter. The device failed and ceased operation.

[0080] During the 1-minute reaction process, since the injection head did not enter the high-temperature area, the injected liquid could not be vaporized in time, and a large amount of liquid would drip into the plasma in the form of large droplets or gather on the quartz tube wall and flow into the plasma. Therefore, the chemical reaction would proceed in the plasma generation area in the form of intermittent bursts, which led to the high uncontrollability and unevenness of the reaction. At the same time, the magnetic field in the plasma jet area could not regulate the reaction. Therefore, although a certain amount of product can be collected, it was found through characterization that the composition of the product is very complex and the product is uneven, including pure graphene, graphene high-entropy alloy composite structure, pure high-entropy alloy, segregated FeCoNi and CrMn alloy, and the element distribution in the high-entropy alloy is also uneven. Its characterization image is as follows: Figure 4 As shown, it can be observed that the composition of the particles is complex, and pure graphene, FeCoNiMnCr, FeCoNi, and MnCr particles all exist at the same time.

[0081] Comparative Example 1-2

[0082] This comparative example is substantially the same as Example 1, with the only difference being that the injection head is inserted into the plasma generating region from above.

[0083] After a period of operation, the quartz tube walls in the resonant cavity (the plasma generation area) also turned black, with large amounts of carbon and metallic deposits. Under the action of microwaves, ignition continued, producing intense sparks. After about a minute, both the sparks and the plasma disappeared. Inspection confirmed that the quartz tube had melted, creating a hole about 5mm in diameter. The device failed and ceased operation.

[0084] During the 1-minute reaction, the precursor liquid injected into the high-temperature area—the plasma generation area—can react continuously and smoothly, but the magnetic field in the plasma injection area cannot control the reaction. Therefore, although a certain amount of product can be collected, characterization shows that the element segregation in the product is still very serious. There are graphene-coated FeCoNiMnCr high-entropy nanoparticles, but there are also by-products, including graphene-coated FeCoNi particles and MnCr particles. Its characterization image is as follows Figure 5 As shown, it can be observed that the elements are severely segregated, and FeCoNiMnCr, FeCoNi, and MnCr particles exist at the same time.

[0085] Example 2

[0086] This embodiment illustrates the preparation process of graphene-coated FeCoNiMnCr high-entropy nanoparticles using the above-mentioned device, as shown below:

[0087] Turn on cooling water circulation machines 1 and 2 to cool the equipment, and turn on oxygen to fill the reaction area with oxygen at a gas flow rate of 10 L / min;

[0088] Turn on the microwave power supply and ignite to generate microwave plasma (no ignition is required for low pressure). The microwave power is 1800 W and the quartz tube diameter is 1 inch.

[0089] The chloride ethanol solution of Fe, Co, Ni, Mn, and Cr was loaded into the precursor reservoir, and the injection head was inserted into the plasma spray zone from the side using a quartz tube with an inlet on the side;

[0090] After the microwave plasma torch is stabilized, turn on the peristaltic pump to deliver the precursor to the ultrasonic atomizer at a rate of 1 mL / min;

[0091] The products were collected and tested to obtain nano- and submicron-sized graphene-coated FeCoNiMnCr high-entropy nanoparticles.

[0092] The above embodiments illustrate that using a specially designed injection head to directly inject the precursor into the plasma injection zone can avoid the deposition of conductive materials in the resonant cavity, ensuring long-term operation of the equipment and continuous preparation of materials. Subsequently, top injection is adopted to directly inject the precursor into the plasma injection zone, and combined with an electromagnetic field generator to control the nucleation growth and assembly process of the material and regulate the dimension of the product.

[0093] Example 3

[0094] This embodiment illustrates the preparation process of low thermal conductivity LaPrDyHoTmTa high entropy oxide nanowires, as shown below:

[0095] La, Pr, Dy, Ho, Tm, and Ta powders were mixed and loaded into a screw feeder;

[0096] Turn on the cooling water circulation to cool the equipment, and turn on the oxygen to fill the reaction area with oxygen at a gas flow rate of 10 L / min;

[0097] Turn on the microwave power supply and ignite to generate microwave plasma (no ignition is required for low pressure). The microwave power is 1800 W and the quartz tube diameter is 1 inch.

[0098] After the microwave plasma torch is stable, the screw feeder containing La, Pr, Dy, Ho, Tm, and Ta powders is turned on to deliver the mixed precursors to the powder spraying device at a rate of 2 g / min, and then sprayed into the reaction area of ​​the high-temperature plasma torch through the powder spraying device;

[0099] Turn on the constant magnetic field generator and control the magnetic field strength, increasing it from 0 mT to 1000 T at 10 mT intervals, and collect the LaPrDyHoTmTa high-entropy oxide nanowires prepared under different magnetic field strengths;

[0100] LaPrDyHoTmTa high-entropy oxide nanowires prepared at different steady-state magnetic field strengths were tested to determine that the aspect ratio of the nanowires increases with increasing steady-state magnetic field strength. Data were collected and collated to determine the structure-activity relationship between aspect ratio and steady-state magnetic field, and a process parameter database was established.

[0101] The thermal conductivity of LaPrDyHoTmTa high-entropy oxide nanowires with different aspect ratios was detected, the best performance (lowest thermal conductivity) was selected, and the corresponding growth parameters were taken from the process parameter database for quantitative preparation.

[0102] Comparative Example 3-1

[0103] Compared with Example 3, in this comparative example, other steps and processes remain unchanged, only the steady magnetic field is turned off, and only zero-dimensional LaPrDyHoTmTa nanoparticles are prepared.

[0104] Comparative Example 3-2

[0105] The difference between this comparative example and Example 3 is that, similar to Comparative Examples 1-2, the length of the injection head is adjusted and the injection head is inserted into the plasma generation zone from above.

[0106] This comparative example not only produces the same tube wall ablation problem as comparative examples 1-2, but also, although products are collected within a limited reaction time, most of the reactions occur in the plasma generation area. The steady magnetic field located in the plasma jet zone cannot regulate the nucleation and growth process of the high-entropy nanoalloy, that is, it cannot promote the directional nucleation and growth of the high-entropy nanoalloy. Therefore, the product does not show the experimental phenomenon in Example 3 that the aspect ratio of the nanowire is strongly correlated with the magnetic field strength. Under a certain magnetic field strength, the vast majority of the collected products are still zero-dimensional nanoparticles, and only a few enter the plasma jet zone and react to form one-dimensional nanowires, but their aspect ratios are polydisperse, and they are a mixture of nanowires with multiple different aspect ratios.

[0107] Example 4

[0108] This embodiment provides a method for preparing FeNiTiCrMnCu high entropy oxide nanosheets with high antibacterial properties, as shown below:

[0109] Mix Fe, Ni, Ti, Cr, Mn and Cu powders evenly and load them into the screw feeder;

[0110] Turn on the cooling water circulation to cool the equipment, and turn on the oxygen to fill the reaction area with oxygen at a gas flow rate of 10 L / min;

[0111] Turn on the microwave power supply and ignite to generate microwave plasma (no ignition is required for low pressure). The microwave power is 1000 W and the diameter of the quartz tube is 1 inch.

[0112] After the microwave plasma torch is stable, the screw feeder containing Fe, Ni, Ti, Cr, Mn, and Cu powders is turned on to deliver the mixed precursor powders to the powder spraying device at a rate of 0.5 g / min and spray them into the reaction area of ​​the high-temperature plasma torch;

[0113] The high-frequency electromagnetic field generator (44 MHz) was turned on, and the electromagnetic field power was increased from 0 W to 500 W at intervals of 50 W. FeNiTiCrMnCu high-entropy oxide nanosheets prepared under different electromagnetic field powers were collected.

[0114] Testing FeNiTiCrMnCu high-entropy oxide nanosheets prepared under different electromagnetic field powers revealed that the nanosheet size increases with increasing electromagnetic field power, ultimately stabilizing. Data were collected and collated to determine the structure-activity relationship between nanosheet size and electromagnetic field power, and to establish a process parameter database.

[0115] The antibacterial properties of FeNiTiCrMnCu high entropy oxide nanosheets with different sizes were detected, the best performance was selected, and the corresponding growth parameters were taken out from the process parameter database for quantitative preparation.

[0116] Comparative Example 4-1

[0117] The other processes remain unchanged, only the high-frequency magnetic field generator is turned off, and only zero-dimensional FeNiTiCrMnCu nanoparticles are prepared.

[0118] Comparative Example 4-2

[0119] The difference between this comparative example and Example 4 is that, similar to Comparative Examples 1-2, the length of the injection head is adjusted and the injection head is inserted into the plasma generation region from above.

[0120] This comparative example not only produces the same tube wall ablation problem as comparative examples 1-2, but also, although products are collected within a limited reaction time, most of the reactions occur in the plasma generation area. The high-frequency magnetic field located in the plasma jet zone cannot regulate the nucleation and growth process of the high-entropy nanoalloy, and cannot promote the directional nucleation and growth of the high-entropy nanoalloy in the two-dimensional plane. Therefore, the vast majority of the products are still zero-dimensional nanoparticles, and only a few products that enter the plasma jet zone and react are two-dimensional nanosheets. They do not show the typical law in Example 4 that the size of the nanosheets increases with the increase of the electromagnetic field power and eventually tends to be stable. Instead, the nanosheet sizes are randomly distributed.

[0121] Example 5

[0122] This embodiment provides a process for manufacturing FeCoNiMoCr high-entropy nano-alloy particles with a heterogeneous structure, which is specifically as follows:

[0123] Mix ethanol solutions of FeCl3, CoCl2, NiCl2, MoCl3, and CrCl3 with a concentration of 1 mol / L and load them into a peristaltic pump;

[0124] Turn on the cooling water circulation to cool the equipment, and turn on the argon gas to fill the reaction area with argon at a gas flow rate of 10 L / min;

[0125] Turn on the microwave power supply and ignite to generate microwave plasma (no ignition is required for low pressure). The microwave power is 1800 W and the quartz tube diameter is 1 inch.

[0126] After the microwave plasma torch is stabilized, turn on the peristaltic pump to deliver the precursor to the ultrasonic atomizer at a rate of 1 mL / min;

[0127] Turn on the ultrasonic atomizer at 100% power and inject the atomized precursor into the high-temperature plasma torch area;

[0128] Turn on the constant electric field generator and adjust the electric field strength, starting from 1000 V / m and increasing the electric field strength by 100 V / m every time until 6000 V / m, and collect the high entropy nanomaterials prepared under different electric field strengths;

[0129] The elemental distribution within the resulting high-entropy nanomaterials was examined, revealing that as the steady-state electric field increases, the elements gradually segregate, forming a heterogeneous structure. One section is enriched in Co and Ni, with less Fe, Mo, and Cr, while another section is enriched in Fe, Mo, and Cr, with less Co and Ni. Furthermore, as the electric field strength increases, the segregation phenomenon intensifies, and the regions enriched in Co and Ni expand. Data were collected and collated to determine the structure-activity relationship between the heterogeneous structure ratio and electric field strength, and a process parameter database was established.

[0130] Comparative Example 5-1

[0131] Other process steps and parameters remain unchanged, and only the steady-state electric field generator is turned off, which can only produce FeCoNiMoCr high-entropy nanoparticles with uniformly mixed elements.

[0132] Comparative Example 5-2

[0133] The difference between this comparative example and Example 5 is that, similar to Comparative Examples 1-2, the length of the injection head is adjusted and the injection head is inserted into the plasma generation region from above.

[0134] This comparative example not only produces the same tube wall ablation problem as comparative examples 1-2, but also, although products are collected within a limited reaction time, most of the reaction occurs in the plasma generation area. The steady electric field located in the plasma injection area cannot regulate the nucleation and growth process of the high-entropy nanoalloy, and cannot control the segregation of different elements. Therefore, although element segregation exists in the product, the segregation situation or the degree of segregation is completely random, and does not show the typical law that the segregation phenomenon intensifies with the increase of the electric field intensity in Example 5. Instead, a mixture of uniformly mixed nanoparticles and segregated nanoparticles is obtained.

[0135] Example 6

[0136] This embodiment illustrates a manufacturing process of FeCoNiMnCr high entropy nano alloy particles with element gradient distribution, as shown below:

[0137] Mix ethanol solutions of FeCl3, CoCl2, NiCl2, MnCl3, and CrCl3 with a concentration of 1 mol / L and load them into the syringe pump;

[0138] Turn on the cooling water circulation to cool the equipment, and turn on the argon gas to fill the reaction area with argon at a gas flow rate of 10 L / min;

[0139] Turn on the microwave power supply and ignite to generate microwave plasma (no ignition is required for low pressure). The microwave power is 1800 W and the quartz tube diameter is 1 inch.

[0140] After the microwave plasma torch is stabilized, turn on the syringe pump to deliver the precursor to the ultrasonic atomizer at a rate of 1 mL / min;

[0141] Turn on the ultrasonic atomizer at 100% power and inject the atomized precursor into the high-temperature plasma torch area;

[0142] Turn on the alternating electric field generator, set the frequency to 100 Hz, adjust the electric field strength, start from 1000 V / m and increase the electric field strength by 100 V / m every time to 6000 V / m, and collect the high entropy nanomaterials prepared under different electric field strengths;

[0143] The field strength was fixed at 2000 V / m, and the frequency of the alternating electric field was adjusted from 0 Hz to 3000 Hz at 50 Hz intervals to collect high-entropy nanomaterials prepared at different frequencies;

[0144] The elemental distribution within the resulting high-entropy nanomaterials was examined, revealing that as the alternating electric field increased, the elements within the material gradually became gradient-like, with the Co and Ni content increasing from one end to the other. However, excessive field strength could lead to the formation of a heterojunction. Furthermore, as the frequency of the alternating electric field increased, the gradient initially intensified and then weakened, with a more pronounced elemental gradient observed in products with frequencies between 50 and 300 Hz. Data were collected and collated to determine the structure-activity relationship between the degree of gradient distribution and the alternating electric field intensity and frequency, enabling the development of a process parameter database.

[0145] Comparative Example 6-1

[0146] The other process steps and parameters remain unchanged, only the alternating electric field generator is turned off, and only FeCoNiMnCr high-entropy nanoparticles with uniform element distribution are prepared.

[0147] Comparative Example 6-2

[0148] Compared with Example 6, this comparative example differs in that: similar to Comparative Examples 1-2, the length of the injection head is adjusted and inserted into the plasma generation area from above.

[0149] This comparative example not only produces the same tube wall ablation problem as comparative examples 1-2, but also, although the product is collected within the limited reaction time, most of the reaction occurs in the plasma generation area. The alternating electric field located in the plasma injection area cannot regulate the nucleation and growth process of the high-entropy nanoalloy, and cannot control the distribution of elements in the product. Therefore, high-entropy nanoparticles with element gradient distribution are not formed, nor does it show the typical law of gradual gradient of elements in high-entropy nanomaterials with the increase of the alternating electric field in Example 6. Instead, a mixture of uniformly mixed nanoparticles and nanoparticles with random element segregation is obtained.

[0150] Based on the above embodiments and comparative examples, it can be clearly seen that the embodiments of the present invention inject the precursor into the plasma injection area to prevent it from entering the resonance cavity area (plasma generation area) to react and deposit conductive materials, thereby preventing the quartz tube from melting due to continuous ignition, thereby ensuring the continuous use of the preparation device and realizing the continuous and high-speed preparation of high-entropy nanomaterials.

[0151] The embodiment of the present invention prevents the precursor from entering the resonant cavity region (plasma generation region) and also prevents the explosive airflow generated by the thermal expansion of the precursor from blowing out the plasma, thereby also ensuring the continuity of the preparation.

[0152] By improving the equipment, the embodiment of the present invention injects the precursor into the plasma injection area, which can avoid the deposition of conductive materials such as metals and carbon within the resonant cavity, thereby preventing the conductive materials from continuously igniting in the high-energy microwaves, generating local ultra-high temperatures and melting the quartz tube. This can improve the life and working stability of the preparation device and ensure the continuous ultra-high-speed preparation of various high-entropy nanomaterials.

[0153] The extreme non-equilibrium translation environment constructed by the microwave plasma torch of the embodiment of the present invention can promote the complete ionization of the injected elements, forming high-energy ions, which can interact with the external magnetic field (or electric field) and move in a directed manner under the action of the Lorentz force (or electric field force), thereby changing the nucleation growth mode of the high-entropy nanomaterial in the high-temperature region and the self-assembly process of the high-entropy nanomaterial already generated in the low-temperature region, thereby preparing -dimensional nanowires / chains or two-dimensional nanosheets.

[0154] It is clear that different ions have different masses and charges. Therefore, under the action of the magnetic field (or electric field), different elements will obtain different movement speeds and movement states, further changing the nucleation and growth mode of high-entropy nanomaterials, and preparing high-entropy nanomaterials with element gradient distribution or heterogeneous structure; and in order to achieve this, it is necessary to set the injection position directly in the plasma jet zone so that the chemical reaction occurs in the plasma jet zone, ensuring that the nucleation and growth of high-entropy nanoparticles can be regulated by the magnetic field (or electric field), thereby realizing uniform distribution of elements (low-frequency magnetic field), one-dimensional directional nucleation and growth (steady magnetic field), two-dimensional directional nucleation and growth (high-frequency magnetic field), controllable segregation of elements (steady electromagnetic), and element gradient distribution (alternating electric field).

[0155] It should be understood that the above embodiments are merely illustrative of the technical concepts and features of the present invention. Their purpose is to enable those skilled in the art to understand the contents of the present invention and implement them accordingly. They are not intended to limit the scope of protection of the present invention. Any equivalent variations or modifications made in accordance with the spirit and substance of the present invention are intended to be encompassed within the scope of protection of the present invention.

Claims

1. A device for preparing multi-dimensional high-entropy nanomaterials, characterized in that: It includes a process tube cavity extending along a specified direction, a plasma generation module, a precursor injection module and an electromagnetic field generation module; The process tube cavity includes a plasma generation area and a plasma injection area in sequence along the specified direction. The plasma generation module is arranged at the plasma generation area, and is used to form plasma inside the process tube cavity and inject the plasma into the plasma injection area along the specified direction. The precursor injection module is used to inject the precursor into the process tube cavity, and includes an injection pipeline, wherein the injection port of the injection pipeline is arranged in the plasma injection area, and the injection direction of the injection port is in the specified direction; The electromagnetic field generating module is arranged in the plasma ejection zone, and is used for applying a controllable electric field and / or magnetic field to the plasma ejection zone.

2. The preparation device according to claim 1, characterized in that The injection pipeline extends in the process cavity through the plasma generating area to the plasma ejection area, and at least the injection pipeline in the plasma generating area is made of insulating material; Alternatively, the injection pipeline enters the process tube cavity from the side wall of the plasma injection zone and turns to extend in the designated direction.

3. The preparation device according to claim 1, characterized in that The injection pipeline includes a precursor passage at a central axis and a cooling interlayer wrapping the precursor passage, and the cooling interlayer is used for circulating a cooling medium.

4. The preparation device according to claim 3, characterized in that The precursor injection module further includes a precursor pumping unit and a cooling medium pumping unit. The precursor pumping unit is communicated with the precursor passage, and the cooling medium pumping unit is communicated with the cooling interlayer.

5. The preparation device according to claim 1, characterized in that The electromagnetic field generating module includes an induction coil and / or a field plate; the induction coil surrounds the plasma injection zone, and / or the plasma injection zone is located between a pair of field plates, and / or the process lumen further includes a lumen inlet and a lumen outlet, and the direction from the lumen inlet to the lumen outlet is the specified direction; the lumen inlet is connected to a process gas pumping module for pumping process gas into the process lumen, and the process gas is excited into a plasma state after passing through the plasma generating zone; The lumen outlet is connected to a collecting device, and the collecting device is used to collect the product.

6. A method for preparing multidimensional high-entropy nanomaterials using the preparation device according to any one of claims 1 to 5, characterized in that: include: Generate plasma from a plasma generating region and eject it into a plasma ejection region along a specified direction; Directly injecting a precursor into the plasma injection zone, wherein the precursor has no contact with the plasma in the plasma generating zone, and a physical-chemical reaction is formed in the plasma injection zone under the action of the plasma; A controllable electric field and / or magnetic field is simultaneously applied to the plasma injection zone to regulate the physical and chemical reaction.

7. The preparation method according to claim 6, characterized in that The precursor includes any one of a metal element, an alloy, a metal salt, and a metal oxide, or a combination of two or more thereof.

8. The preparation method according to claim 6, characterized in that The process tube cavity contains a process gas flowing along the specified direction, and the process gas is used to form the plasma; the injection pipeline contains a carrier gas, and the carrier gas is used to transport the precursor.

9. The preparation method according to claim 8, characterized in that The process gas and / or carrier gas includes any one of argon, helium, neon, oxygen, air, nitrogen, ammonia, methane, ethane, and ethylene, or a combination of two or more thereof.

10. Application of the multidimensional high-entropy nanomaterials prepared by the preparation method according to any one of claims 6 to 9 in the fields of energy and catalysis, coatings, electronic devices, and optical devices.

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