CN111705378A - Method for Rapid Growth of Transition Metal Carbide Nanodots on Carbon-Based Supports Using Microwave Combustion and Its Application - Google Patents

Abstract

The invention provides a method for rapidly growing transition metal carbide nano-dots on a carbon-based carrier by microwave combustion and its application. In the method, the reactant precursor is obtained by mixing the carbon-based material and the transition metal precursor solution, and freeze-drying to remove water; The carbon-based material loaded with ultra-fine transition metal carbide nano-dots is obtained after microwave treatment, cleaning and drying. The reactant precursor prepared by the invention has a strong ability to absorb microwaves. After absorbing microwaves in an air atmosphere, the carbon-based materials undergo microwave pyrolysis and combustion, and are bonded with transition metals to form transition metal carbides; The wire transfers some of the heat generated by the absorbing wave, preventing the carbon-based material from burning too much. The preparation method of the invention is simple and fast, has low cost, is not easy to agglomerate, and has excellent electrocatalytic performance.

Description

Rapid Growth of Transition Metal Carbide Nanodots on Carbon-Based Supports Using Microwave Combustion method and its application

technical field

The invention belongs to the technical field of functional nanomaterial preparation, and in particular relates to a method for rapidly growing transition metal carbide nanodots on a carbon-based carrier by microwave combustion and its application.

Background technique

Due to their structural stability, corrosion resistance, high hardness, high electrical and thermal conductivity and other characteristics, transition metal carbides have great research value and application prospects in the fields of energy conversion and storage, catalytic conversion, protective coatings, advanced ceramics, etc. . Especially in the field of electrocatalysis, transition metal carbides exhibit noble metal-like properties, such as hydrogen-related reactions, hydrazine decomposition reactions, and isomerization reactions. The high catalytic activity and low cost brought by its platinum-like structure make it have greater application potential than traditional electrocatalytic materials, which has attracted extensive attention and research. However, the traditional preparation methods of transition metal carbides mainly include high-temperature synthesis method, temperature-programmed reaction method, carbothermic hydrogen reduction method, chemical vapor deposition method, thermal decomposition method, ultrasonic synthesis method and solid-state exchange reaction method. Generally, it needs to be carried out at high temperature, the reaction conditions are extremely harsh, and the preparation process is cumbersome. The prepared carbides have problems such as low specific surface area, large particle size and easy agglomeration, and need to pass inert gas passivation before exposure to air. The low point density seriously affects its electrocatalytic performance. This problem can be effectively solved by preparing ultra-micro-sized nanoparticles or nanodots with good thermal stability.

For example, Chinese invention patent CN110102236 discloses a preparation method and application of a monodisperse metal composite rapidly supported and grown on a flexible carbon substrate by microwave technology. In the method, carbon precursors and metal salts are mixed and dissolved, drop-coated on a microwave-activated flexible carbon substrate, and subjected to microwave treatment in an inert atmosphere or a reducing atmosphere to obtain a monodisperse metal composite supported and grown on the flexible carbon substrate. Chinese invention patent CN101371988 discloses a preparation method and application of a transition metal carbide catalyst material. The method uses carbon materials, oxides or molecular sieves as carriers, and transition metal compounds as precursors. After mixing, microwave pyrolysis is used in an inert atmosphere or a reducing atmosphere to obtain a catalyst supporting transition metal carbides. However, the above method is not conducive to its modification research and large-scale production application at the nanoscale due to the inability to control the nanoscale of the product, the reaction in a special atmosphere, the numerous procedures, and the long time (5-30 min), etc.

Therefore, there is an urgent need to provide a method for efficiently preparing ultrafine metal carbides with high specific surface area.

SUMMARY OF THE INVENTION

In view of the above-mentioned defects in the prior art, the purpose of the present invention is to provide a method for rapidly growing transition metal carbide nanodots on a carbon-based carrier by microwave combustion and its application. The reactant precursor with high wave absorption and high thermal conductivity is used to absorb microwaves in the air atmosphere, so that the carbon-based material undergoes microwave pyrolysis combustion and the transition metal is bonded to form transition metal carbide; The heat transfer generated by the wave prevents the carbon-based material from burning excessively, thereby producing a high-performance, highly dispersed carbon-based material loaded with ultrafine transition metal carbide nanodots.

To achieve the above object, the present invention adopts the following technical solutions to realize:

A method for rapidly growing transition metal carbide nanodots on a carbon-based carrier by microwave combustion, comprising the following steps:

S1. The carbon-based material and the transition metal precursor are added to a mixed solvent of ethanol and water, and after mixing uniformly, freeze-drying is performed to obtain a reactant precursor;

S2. The reactant precursor obtained in step S1 is transferred to a microwave carrying container, and a heat-conducting metal wire is placed in the microwave carrying container;

S3. The microwave load-carrying vessel obtained in step S2 is placed in a microwave generator, and the discharge load-carrying vessel is subjected to microwave treatment in an air atmosphere, and then taken out for cleaning and drying to obtain loaded ultrafine transition metal carbide nanodots of carbon-based materials.

By adopting the above technical scheme, firstly, the carbon-based material is mixed with the transition metal precursor solution, and then the solvent, especially the moisture in the solvent, is removed by freeze-drying to obtain a reactant precursor with high wave absorption and high thermal conductivity. In the air atmosphere, the reactant precursor with high microwave absorption and high thermal conductivity will have a sharp increase in temperature due to the principle of electrical conduction loss or magnetic loss after absorbing microwaves. At the same time, due to the behavior of reflected microwaves, there will be a large number of free electrons accumulated at the tip of the metal wire, and when the degree is large, an arc phenomenon can be generated, igniting the precursor of the reactant. This process makes the carbon-based materials in the reactant precursor undergo microwave pyrolysis combustion to form carbon defect sites; anchor the metal atoms in the transition metal precursor, and carbonize at high temperature to finally form ultrafine transition metal carbide nanodots. The generated ultrafine transition metal carbide nanodots can further improve the wave absorbing ability of the material, thereby promoting the growth rate of the ultrafine transition metal carbide nanodots, so as to efficiently prepare carbon-based nanodots loaded with ultrafine transition metal carbide nanodots. Material. In the present invention, the heat-conducting metal wire is cleverly placed in the microwave carrying container, which not only plays the role of ignition, but also can transfer the heat generated by the wave absorption of some reactant precursors, so as to prevent the carbon-based material from burning excessively in the whole preparation process, thereby preventing The preparation process is regulated.

Further, in step S1, the freeze-drying method includes: firstly using liquid nitrogen to perform rapid freeze-drying for 5-10 minutes, and then freeze-drying in a freeze-drying machine for 6-12 hours. The solvent in the solution, especially the moisture in the solution, is removed by freeze-drying, so as to prevent the polarity loss caused by the moisture absorption of microwaves, which will affect the growth rate of ultrafine transition metal carbide nanodots. Moreover, the use of freeze-drying can maintain the original dispersion state of the reactant precursor and improve the loading uniformity of the subsequent ultrafine transition metal carbide nanodots.

Further, in step S1, the concentration of the transition metal precursor is 0.5-10 mg/mL; the mass ratio of the carbon-based material to the transition metal precursor is 5:1-20:1. By adjusting the concentration of transition metal precursor solution and the mass ratio of carbon-based material to transition metal precursor, the wave absorbing ability of reactant precursor and the growth rate, uniformity and loading of ultrafine transition metal carbide nanodots can be regulated. .

Further, the carbon-based material includes, but is not limited to, one or more of conductive carbon fibers, conductive carbon black, carbon nanotubes, and graphene; the transition metal precursors are transition metal salts, transition metal peroxygen One or more of acids, transition metal complexes or transition metal carbonyl compounds. This type of conductive carbon-based material is selected as the carrier, which has a large specific surface area, good electrical conductivity, and is easy to form defect sites and form carbides with transition metals. Therefore, the prepared carbon-based material loaded with ultrafine transition metal carbide nanodots has high activity, high electrical conductivity, excellent volume utilization, and can show excellent performance in electrocatalytic hydrogen evolution.

Further, in step S2, the thermally conductive metal wire is any one of silver metal wire, copper metal wire, gold metal wire, and aluminum metal wire. Preferably, the thermally conductive metal wire is a copper metal wire.

Further, the length of the metal wire is 5-10 cm, and the diameter is 0.1-0.3 cm. By placing the heat-conducting metal wire in the microwave carrying container, the heat generated by the wave absorption of part of the reactant precursor can be transferred to prevent excessive combustion of the carbon-based material during the entire preparation process, thereby regulating the preparation process.

Further, in step S2, the microwave carrying container is a quartz beaker; the microwave generator is a microwave oven. The method provided by the invention does not have high requirements on equipment, and can realize the rapid growth of ultrafine transition metal carbide nano-dots on carbon-based materials in an air atmosphere by simply using a domestic microwave oven.

Further, in step S3, the power of the microwave treatment is 400-900W, and the time is 10-140s. The growth rate and loading of ultrafine transition metal carbide nanodots can be regulated by adjusting the microwave power and microwave treatment time.

Further, in step S3, the cleaning is performed sequentially with dilute hydrochloric acid or alkali and deionized water.

Application of a carbon-based material loaded with ultrafine transition metal carbide nanodots prepared by the above method, the carbon-based support loaded with transition metal carbide nanodots is used in energy storage, electrocatalytic hydrogen evolution, and fuel cell electrode reactions. applications in the field. The carbon-based material loaded with ultrafine transition metal carbide nano-dots prepared by the invention has high loading capacity, high activity and high stability, and is used in the fields of energy storage, electrocatalytic hydrogen evolution, fuel cell electrode reaction and the like, all showing good performance. performance.

beneficial effect

Compared with the prior art, the method for rapidly growing transition metal carbide nanodots on a carbon-based carrier by microwave combustion and application thereof provided by the present invention have the following beneficial effects:

(1) The method for rapidly growing transition metal carbide nanodots on a carbon-based carrier using microwave combustion provided by the present invention utilizes a reactant precursor with high wave absorption and high thermal conductivity to absorb microwaves in an air atmosphere to make its temperature rise. At the same time, due to the reflected microwave behavior of the metal wire, there will be a large amount of free electrons accumulated at its tip. When the degree is large, an arc phenomenon will occur, igniting the precursor of the reactant, and causing the carbon-based material to undergo microwave pyrolysis combustion and transition. The metal atoms are anchored to generate transition metal carbide nanodots. The resulting ultrafine transition metal carbide nanodots can further improve the material's ability to absorb waves, thereby promoting the growth rate of the ultrafine transition metal carbide nanodots. At the same time, in the present invention, the heat-conducting metal wire is cleverly placed in the microwave carrying container, which not only plays the role of ignition, but also can transfer the heat generated by the wave absorption of part of the reactant precursor, so as to prevent the carbon-based material from burning during the whole preparation process. Excessive, thereby regulating the preparation process.

(2) The method for rapidly growing transition metal carbide nanodots on carbon-based carriers by microwave combustion provided by the present invention, by preparing reactant precursors with high wave absorption and high thermal conductivity, only using a microwave oven in an air atmosphere, The carbon-based material loaded with ultrafine transition metal carbide nanodots can be quickly prepared, and has the advantages of simple and rapid preparation method, low cost and high repeatability, and is suitable for large-scale production. In addition, the prepared ultrafine transition metal carbide nano-dots have good dispersibility on carbon-based materials, high specific surface area, and are not easy to agglomerate.

(3) The method for rapidly growing transition metal carbide nanodots on carbon-based carriers by microwave combustion provided by the present invention can successfully prepare loaded ultra-micro Mo ₂ C, W ₂ C, VC, Fe ₃ C, NbC, TaC The graphene fibers of nanodots have excellent electrocatalytic hydrogen evolution performance. This simple and fast preparation method can meet more application fields and industrial needs in the near future, and has great practical application value.

Description of drawings

Fig. 1 is the scanning electron microscope of the graphene carbon fiber of the load ultrafine transition metal carbide nano-dot prepared by the present invention;

Fig. 2 is the Raman spectrogram of the graphene carbon fiber loaded with ultrafine transition metal carbide nanodots prepared in Example 1;

3 is a graph showing the electrocatalytic hydrogen evolution performance of 20% Pt/C material and graphene carbon fibers loaded with ultrafine transition metal carbide nanodots prepared in Examples 1 to 6.

Detailed ways

The technical solutions of the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments; based on the embodiments of the present invention, common All other embodiments obtained by the skilled person without creative work fall within the protection scope of the present invention.

Example 1

A method for rapidly growing ultrafine molybdenum carbide nanodots on a carbon-based carrier using microwave combustion, comprising the following steps:

S1. 200g graphene fibers were added to the ethanol and water mixed solution of 20mL, 1mg/mL of peroxymolybdic acid, and fully mixed with an ultrasonic cell pulverizer; then liquid nitrogen was used to carry out the rapid freeze-drying treatment of the solution for 10min, Then put the sample into a 100mL plastic beaker, transfer it to a freeze dryer and freeze-dry it again for 12 hours to obtain a reactant precursor; the composite composed of the graphene fiber and peroxytungstic acid has good wave-absorbing performance.

S2. Transfer the reactant precursor obtained in step S1 to a 100 mL quartz beaker, and insert a copper wire with a length of 5 cm and a diameter of 0.2 cm into it for heat conduction; In addition to the role of ignition, the copper wire can also transfer the heat generated by the wave absorption of some reactant precursors to prevent excessive combustion of carbon-based materials during the entire preparation process, thereby regulating the preparation process.

S3. The quartz beaker obtained in step S2 is placed in a microwave oven, and microwave treatment is carried out in an air atmosphere for about 120s, and the microwave power is 750W; then the sample is taken out from the quartz beaker, and 0.1M sodium hydroxide and deionized water are used. The sample is cleaned and dried to obtain the graphene carbon fiber loaded with ultra-fine molybdenum carbide (Mo ₂ C) nano-dots. When the reactant precursor is in the air atmosphere, after absorbing microwaves, the temperature rises sharply. At the same time, due to the behavior of reflecting microwaves, there will be a large number of free electrons accumulated at the tip of the metal wire. When the degree is large, an arc phenomenon can occur. Ignite the reactant precursor. This process makes the carbon-based materials in the reactant precursor undergo microwave pyrolysis combustion to form carbon defect sites; anchor the metal atoms in the transition metal precursor, and carbonize at high temperature to finally form ultrafine transition metal carbide nanodots. The generated ultrafine transition metal carbide nanodots can further improve the wave absorbing ability of the material, thereby promoting the growth rate of the ultrafine transition metal carbide nanodots, so as to efficiently prepare carbon-based nanodots loaded with ultrafine transition metal carbide nanodots. Material.

Please refer to FIG. 1 and FIG. 2 , it can be seen that the present invention successfully prepares the graphene fibers loaded with ultra-fine molybdenum carbide nano-dots, and the dispersion uniformity of the ultra-fine molybdenum carbide nano-dots is good.

Referring to Fig. 3, it can be seen that the Mo ₂ C nanodots prepared by this method have a small onset potential in the electrocatalytic hydrogen evolution reaction, and the Tafel value is 59mV/dec, showing excellent performance.

Example 2

A method for rapidly growing ultrafine tungsten carbide nanodots on a carbon-based carrier using microwave combustion, comprising the following steps:

S1. 200g graphene fibers were added to 20mL, 2mg/mL of peroxytungstic acid mixed solution of ethanol and water, and fully mixed with an ultrasonic cell pulverizer; then liquid nitrogen was used to carry out the rapid freeze-drying treatment of the solution for 10min, Then put the sample into a 100mL plastic beaker, transfer it to a freeze-drying machine and freeze-dry it again for 12h to obtain the reactant precursor;

S2. The reactant precursor obtained in step S1 is transferred to a 100 mL quartz beaker, and a copper wire with a length of 5 cm and a diameter of 0.2 cm is inserted therein to conduct heat;

S3. The quartz beaker obtained in step S2 is placed in a microwave oven, and the microwave treatment is carried out for about 90s in an air atmosphere, and the microwave power is 750W; The sample is washed and dried to obtain the graphene carbon fiber loaded with ultrafine tungsten carbide (W ₂ C) nanodots.

Referring to Fig. 3, it can be seen that the onset potential of the W ₂ C nanodots prepared by this method is small in the electrocatalytic hydrogen evolution reaction, and the Tafel value is 55mV/dec, showing excellent performance.

Example 3

A method for rapidly growing ultrafine vanadium carbide nanodots on a carbon-based carrier using microwave combustion, comprising the following steps:

S1. 200g graphene fibers were added to the ethanol and water mixed solution of 5mL, 5mg/mL of ammonium metavanadate, and fully mixed with an ultrasonic cell pulverizer; then the solution was subjected to a 10min rapid freeze-drying process with liquid nitrogen, Then put the sample into a 100mL plastic beaker, transfer it to a freeze-drying machine and freeze-dry it again for 12h to obtain the reactant precursor;

S2. The reactant precursor obtained in step S1 is transferred to a 100 mL quartz beaker, and a copper wire with a length of 5 cm and a diameter of 0.2 cm is inserted therein to conduct heat;

S3. The quartz beaker obtained in step S2 is placed in a microwave oven, and microwave treatment is performed for about 120 s in an air atmosphere, and the microwave power is 600W; The sample is cleaned and dried to obtain graphene carbon fibers loaded with ultrafine vanadium carbide (VC) nanodots.

Referring to Figure 3, it can be seen that the onset potential of the VC nanodots prepared by this method is small in the electrocatalytic hydrogen evolution reaction, and the Tafel value is 68mV/dec, showing excellent performance.

Example 4

A method for rapidly growing ultrafine iron carbide nanodots on a carbon-based carrier by microwave combustion, comprising the following steps:

S1. 200g graphene fibers were added to 10mL, 0.5mg/mL of ferric oleate in ethanol and water mixed solution, and were fully mixed with an ultrasonic cell pulverizer; then liquid nitrogen was used to carry out the rapid freeze-drying treatment of the solution for 10min, Then put the sample into a 100mL plastic beaker, transfer it to a freeze-drying machine and freeze-dry it again for 12h to obtain the reactant precursor;

S2. The reactant precursor obtained in step S1 is transferred to a 100 mL quartz beaker, and a copper wire with a length of 5 cm and a diameter of 0.2 cm is inserted therein to conduct heat;

S3. The quartz beaker obtained in step S2 is placed in a microwave oven, and microwave treatment is performed for about 120 s in an air atmosphere, and the microwave power is 600W; The sample is washed and dried to obtain the graphene carbon fiber loaded with ultrafine iron carbide (Fe ₃ C) nano-dots.

Referring to Fig. 3, it can be seen that the Fe ₃ C nanodots prepared by this method have a small onset potential in the electrocatalytic hydrogen evolution reaction, but the Tafel value is 79mV/dec, and the performance is average.

Example 5

A method for rapidly growing ultrafine niobium carbide nanodots on a carbon-based carrier by microwave combustion, comprising the following steps:

S1. Add 200g graphene fibers to 10mL, 1mg/mL ethanol solution of niobic acid, and fully mix with an ultrasonic cell pulverizer; then use liquid nitrogen to quickly freeze-dry the solution for 10min, and then put the sample into In a 100mL plastic beaker, transfer to a freeze dryer and freeze-dry again for 12h to obtain the reactant precursor;

S2. The reactant precursor obtained in step S1 is transferred to a 100 mL quartz beaker, and a copper wire with a length of 5 cm and a diameter of 0.2 cm is inserted therein to conduct heat;

S3. The quartz beaker obtained in step S2 is placed in a microwave oven, and microwaved for about 120 s in an air atmosphere, and the microwave power is 900W; The sample is cleaned and dried to obtain the graphene carbon fiber loaded with ultrafine niobium carbide (NbC) nanodots.

Referring to Fig. 3, it can be seen that the onset potential of NbC nanodots prepared by this method is small in the electrocatalytic hydrogen evolution reaction, but the Tafel value is 122mV/dec, and the performance is poor.

Example 6

A method for rapidly growing ultrafine tantalum carbide nanodots on a carbon-based carrier using microwave combustion, comprising the following steps:

S1. 200g graphene fibers were added to 10mL, 1mg/mL ethanolic solution of tantalum chloride, and fully mixed with an ultrasonic cell pulverizer; then the solution was subjected to rapid freeze-drying for 10min with liquid nitrogen, and then the sample was placed in Put it into a 100mL plastic beaker, transfer it to a freeze dryer and freeze-dry it again for 12h to obtain the reactant precursor;

S2. The reactant precursor obtained in step S1 is transferred to a 100 mL quartz beaker, and a copper wire with a length of 5 cm and a diameter of 0.2 cm is inserted therein to conduct heat;

S3. The quartz beaker obtained in step S2 is placed in a microwave oven, and microwave treatment is carried out for about 140s in an air atmosphere, and the microwave power is 900W; The sample is cleaned and dried to obtain a graphene carbon fiber loaded with ultrafine tantalum carbide (TaC) nanodots.

Referring to Figure 3, it can be seen that the TaC nanodots prepared by this method have a large onset potential in the electrocatalytic hydrogen evolution reaction, the Tafel value is 99mV/dec, and the performance is average.

Comparative Example 1

A method for rapidly growing molybdenum carbide nanodots on a carbon-based carrier using microwave combustion. Compared with Example 1, the difference is that step S2 includes transferring the reactant precursor obtained in step S1 to 100 mL of quartz In the beaker, that is, no thermal conductive wire is placed in the quartz beaker. Others are substantially the same as those in Embodiment 1, and are not repeated here.

The experimental results show that, because no copper wire is added, the dielectric strength in the air atmosphere is insufficient, and the reactant cannot be ignited and reacted, that is, the graphene fiber loaded with ultra-fine molybdenum carbide nanodots cannot be obtained.

To sum up, the present invention utilizes the reactant precursor with high microwave absorption and high thermal conductivity to absorb microwave in air atmosphere to increase its temperature. At the same time, due to the reflected microwave behavior of the metal wire, there will be a large amount of free electrons accumulated at its tip. When the degree is large, an arc phenomenon will occur, igniting the precursor of the reactant, and causing the carbon-based material to undergo microwave pyrolysis combustion and transition. The metal atoms are anchored to generate transition metal carbide nanodots. The resulting ultrafine transition metal carbide nanodots can further improve the material's ability to absorb waves, thereby promoting the growth rate of the ultrafine transition metal carbide nanodots. At the same time, in the present invention, the heat-conducting metal wire is cleverly placed in the microwave carrying container, which not only plays the role of ignition, but also can transfer the heat generated by the wave absorption of part of the reactant precursor, so as to prevent the carbon-based material from burning during the whole preparation process. Excessive, thereby regulating the preparation process.

The above description is only a preferred embodiment of the present invention, but the protection scope of the present invention is not limited to this. The equivalent replacement or change of the inventive concept thereof shall be included within the protection scope of the present invention.

Claims (10)

1. A method for rapidly growing transition metal carbide nano-dots on a carbon-based carrier by utilizing microwave combustion is characterized by comprising the following steps:

s1, adding a carbon-based material and a transition metal precursor into a mixed solvent of ethanol and water, uniformly mixing, and performing freeze drying treatment to obtain a reactant precursor;

s2, transferring the reactant precursor obtained in the step S1 to a microwave bearing container, and putting a heat conducting metal wire into the microwave bearing container;

and S3, placing the microwave bearing container obtained in the step S2 in a microwave generator, carrying out microwave treatment on the discharge bearing container in an air atmosphere, taking out, cleaning and drying to obtain the carbon-based material loaded with the ultramicro transition metal carbide nanodots.

2. The method for rapid growth of transition metal carbide nanodots on a carbon-based support using microwave combustion as claimed in claim 1, wherein the freeze-drying process comprises, in step S1: firstly, liquid nitrogen is adopted for carrying out rapid freeze drying treatment for 5-10 min, and then the freeze drying is carried out in a freeze dryer for 6-12 h.

3. The method for rapidly growing transition metal carbide nanodots on a carbon-based carrier by using microwave combustion as claimed in claim 1, wherein in the step S1, the concentration of the transition metal precursor is 0.5-10 mg/mL; the mass ratio of the carbon-based material to the transition metal precursor is 5: 1-20: 1.

4. the method for rapidly growing transition metal carbide nanodots on a carbon-based support by using microwave combustion as claimed in any one of claims 1 to 3, wherein the carbon-based material comprises but is not limited to one or more of conductive carbon fiber, conductive carbon black, carbon nanotube, graphene; the transition metal precursor is one or more of transition metal salts, transition metal peroxoacids, transition metal complexes or transition metal carbonyl compounds.

5. The method for rapidly growing transition metal carbide nanodots on a carbon-based carrier using microwave combustion as claimed in claim 1 or 4, wherein the heat conductive metal wire is any one of silver metal wire, copper metal wire, gold metal wire, and aluminum metal wire in step S2.

6. The method for rapidly growing transition metal carbide nanodots on a carbon-based carrier by using microwave combustion as claimed in claim 5, wherein the metal wire has a length of 5 to 10cm and a diameter of 0.1 to 0.3 cm.

7. The method for rapid growth of transition metal carbide nanodots on a carbon-based support using microwave combustion as claimed in claim 1, wherein the microwave-supporting container is a quartz beaker in step S2; the microwave generator is a microwave oven.

8. The method for rapidly growing transition metal carbide nanodots on a carbon-based carrier by using microwave combustion as claimed in claim 1, wherein the microwave treatment power is 400 to 900W and the time is 10 to 140S in step S3.

9. The method for rapidly growing transition metal carbide nanodots on a carbon-based carrier using microwave combustion as claimed in claim 1, wherein the washing is performed using dilute hydrochloric acid or alkali and deionized water in sequence at step S3.

10. Use of the carbon-based material loaded with ultrafine transition metal carbide nanodots prepared by the method according to any one of claims 1 to 9, wherein the transition metal carbide nanodot-loaded carbon-based support is used in the fields of energy storage, electrocatalytic hydrogen evolution, and fuel cell electrode reaction.

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