Synthesis method and application of one-dimensional molybdenum carbide fiber with controllable crystal phase ratio

Abstract

The application discloses a synthesis method and application of one-dimensional molybdenum carbide fibers with controllable crystal phase ratio, and belongs to the technical field of nanofiber preparation. The technical scheme is as follows: a carbon source and a molybdenum source are dissolved in a solvent to form a spinning stock solution, the spinning stock solution is prepared into a fiber membrane through a spinning method, and pre-oxidation is carried out under air or oxygen conditions; a carbothermal reduction reaction occurs in an inert atmosphere, different crystal structure molybdenum carbides are formed by controlling the reduction ability of the carbon source on the molybdenum source; and the different crystal structures include one phase or a mixed structure of two phases of metastable alpha-MoC and stable beta-Mo2C. In the reaction of preparing molybdenum carbide by carbothermal reduction of the carbon fiber, the reduction ability of the carbon can be adjusted to realize continuous conversion from the metastable alpha-MoC to the stable beta-Mo2C phase, and the safe, simple, efficient and flexible preparation method greatly reduces the difficulty and cost of material preparation, and provides a basis for the wide application of the molybdenum carbide material in different fields.

Description

Technical Field

[0001] The present invention belongs to the technical field of nanofiber preparation, and in particular relates to a synthesis method and application of one-dimensional molybdenum carbide fiber with controllable crystal phase ratio. Background Art

[0002] As an important class of transition metal carbides, molybdenum carbide has unique chemical and physical properties due to its electronic structure similar to that of precious metals. α-MoC and β-Mo2C, as the main crystal phases of molybdenum carbide, show remarkable multifunctionality. For example, in the field of catalysis, carbides often have catalytic effects comparable to those of precious metals. In thermal catalytic reactions, molybdenum carbide has attracted widespread attention in the fields of chemical conversion and energy due to its excellent catalytic performance. The application of β-Mo2C in hydrogenation reactions and water-gas shift reactions is particularly prominent, and it plays a key role in the preparation of synthesis gas and chemical energy conversion. In terms of electrochemical applications, the excellent performance of β-Mo2C in the process of hydrogen production by water electrolysis, especially in the hydrogen evolution reaction (HER), demonstrates its importance in the field of electrocatalysis. In addition, since carbide itself has good thermal stability and chemical stability, its application in the ocean also has good prospects. In recent years, the electrolysis of seawater technology has attracted widespread attention. In the seawater environment, the chloride ion-rich environment is very easy to corrode the catalyst. Thanks to the good chemical stability of molybdenum carbide and its good electrocatalyst itself, it has important application prospects in the electrolysis of seawater.

[0003] In fuel cell technology, β-Mo2C has emerged as a promising electrode material, with broad application prospects in energy conversion technologies. Furthermore, the superconducting properties of α-Mo2C at low temperatures provide an important experimental platform for studying superconductivity. In the research of high-temperature resistant materials, β-Mo2C has attracted attention due to its high melting point and superior mechanical properties. These properties make β-Mo2C highly promising for aerospace and high-temperature industrial applications. Furthermore, the stability of molybdenum carbide in high-temperature environments provides a key material solution for high-temperature resistant materials used in high-temperature processes. Molybdenum carbide's high hardness and excellent wear resistance make it an ideal choice for manufacturing cutting tools and wear-resistant coatings. These applications not only improve the durability and efficiency of industrial equipment but also drive innovation in materials engineering. In addition to single-phase molybdenum carbide catalysts, recent research has demonstrated that mixed-phase α-MoC and β-Mo2C catalysts leverage the unique physical and chemical properties of their respective configurations in various fields, further enhancing performance in these applications. In summary, as multifunctional materials, α-MoC and β-Mo2C have demonstrated their unique application value and broad research prospects in the fields of thermal catalysis, electrocatalysis, superconductivity, heat resistance and wear resistance. Therefore, the preparation of molybdenum carbide nanomaterials with different crystal phase structures is very important.

[0004] At present, there are many problems in the preparation process of molybdenum carbide, β-Mo2C is generally considered to be a stable phase of molybdenum carbide, and α-MoC is always regarded as a metastable phase of molybdenum carbide, and there is a great difficulty in the preparation of α-MoC. For example, a mixed gas atmosphere of reducing gas (such as hydrogen) and gaseous carbon source (such as methane gas) is usually used, and under the catalysis of noble metal (rhodium, platinum, palladium, etc.), α-MoC can be obtained by sintering metal molybdenum source (such as metal molybdenum, molybdenum oxide, etc.) at high temperature. The preparation process is relatively complicated, and the use of mixed gas atmosphere brings certain safety hazards, and the use of noble metal also increases the cost of preparation. Most importantly, the controllable two-phase mixed material preparation is difficult, which hinders the exploration of its in the above-mentioned fields and other potential fields. SUMMARY

[0005] The application provides a synthesis method and application of one-dimensional molybdenum carbide fiber with controllable crystal phase ratio. In the reaction of preparing molybdenum carbide by carbon thermal reduction of carbon fiber, the continuous conversion from metastable α-MoC to stable β-Mo2C phase can be realized by adjusting the reduction ability of carbon. The safe, simple, efficient and flexible preparation method greatly reduces the difficulty and cost of material preparation, and provides a basis for the wide application of molybdenum carbide materials in different fields.

[0006] The technical scheme of the application is as follows:

[0007] In a first aspect, a synthesis method of one-dimensional molybdenum carbide fiber with controllable crystal phase ratio is disclosed. A carbon source and a molybdenum source are dissolved in a solvent to form a spinning solution, which is prepared into a fiber membrane by a spinning method, and pre-oxidized in air or oxygen. A carbon thermal reduction reaction occurs in an inert atmosphere, and different crystal structures of molybdenum carbide are formed by controlling the reduction ability of the carbon source to the molybdenum source. The carbon source is a high molecular polymer. The molybdenum source is one of ammonium molybdate, sodium molybdate, molybdic acid, molybdenum acetylacetone, molybdenum powder and molybdenum oxide. The different crystal structures include one phase or two-phase mixed structure of metastable α-MoC and stable β-Mo2C.

[0008] Preferably, the control of the reduction ability of the carbon source to the molybdenum source includes adjusting the relative content of the carbon source and the molybdenum source, specifically: when the mass ratio of the carbon source and the molybdenum source is greater than or equal to 1:1, a metastable α-MoC phase is obtained; when the mass ratio of the carbon source and the molybdenum source is less than or equal to 1:3, a stable β-Mo2C phase is obtained; when the mass ratio of the carbon source and the molybdenum source is greater than 1:3 and less than 1:1, a mixed phase of metastable α-MoC and stable β-Mo2C is obtained. By keeping the content of the carbon source unchanged and changing the amount of the metal molybdenum source in the fiber preparation process, the carbon thermal reduction ability of the unit molybdenum source is controlled. By keeping the content of the high polymer unchanged and pre-oxidizing the high polymer fiber at the same temperature under air conditions, the content of the high polymer is kept unchanged, and by changing the content of the metal molybdenum source, the carbon thermal reduction ability of the unit molybdenum source is reduced, and the two kinds of molybdenum carbide crystal phases in any proportion can also be continuously and accurately obtained.

[0009] Preferably, the control of the reduction ability of the carbon source to the molybdenum source also includes adjusting the pre-oxidation temperature, specifically: when the pre-oxidation temperature is less than or equal to 260℃, a metastable α-MoC phase is obtained; when the pre-oxidation temperature is greater than or equal to 360℃ and less than 600℃, a stable β-Mo2C phase is obtained; when the pre-oxidation temperature is greater than 260℃ and less than 360℃, a mixed phase of metastable α-MoC and stable β-Mo2C is obtained; first, a high polymer-based fiber with a metal molybdenum source is prepared by a fiber preparation method such as electrospinning, and then the high polymer fiber is pre-oxidized under air conditions, the pre-oxidation temperature is controlled, and as the pre-oxidation temperature increases, the content of carbon gradually decreases and the reduction ability decreases, which can make the crystal phase of molybdenum carbide gradually change from α-MoC to β-Mo2C, and during the control process, pure phase α-MoC or pure phase β-Mo2C molybdenum carbide material can also be obtained.

[0010] Preferably, the control of the reduction ability of the carbon source to the molybdenum source also includes post-oxidation treatment, specifically: the metastable α-MoC phase is post-treated to obtain a stable β-Mo2C phase and a mixed phase of metastable α-MoC and stable β-Mo2C, when the post-oxidation temperature is at room temperature to 310℃, a mixed phase of metastable α-MoC and stable β-Mo2C is obtained, and when the post-oxidation temperature is greater than 310℃, a stable β-Mo2C phase is obtained; α-MoC (or two-phase mixed material) post-oxidation treatment indirectly changes to a mixed phase or a β-Mo2C single phase. The prepared α-MoC fiber is post-oxidized under air or oxygen conditions, re-annealed under inert gas conditions, the content of carbon in the α-MoC sample is reduced, and the change of α-MoC to other crystal phases can also be realized. According to the different post-oxidation treatment temperatures, the purpose of continuous and accurate control of the two proportions can also be achieved.

[0011] Preferably, the high molecular polymer is one or a mixture of polyacrylonitrile (PAN), polyvinyl pyrrolidone (PVP), polyvinyl alcohol (PVA) and polylactic acid (PLA).

[0012] Preferably, the solvent is one or a mixture of N,N-dimethylformamide, water, ethanol and chloroform.

[0013] Preferably, the high voltage applied during spinning is 8-30 KV, the distance between the spinning tip and the collecting device is 8-30 cm, and the spinning time is 2-50 hours; after the spinning is completed, a polymer membrane is obtained.

[0014] Preferably, the pre-oxidation is to anneal the fiber membrane in air or oxygen at a heating rate of 0.5-20°C / min, from room temperature to 600°C, for 0.5-20 hours.

[0015] Preferably, the carbothermal reduction reaction is performed by annealing in an inert atmosphere at a temperature of 600-1200° C. at a rate of 0.5-20° C. / min for 1-12 hours.

[0016] The second aspect discloses a method for synthesizing one-dimensional molybdenum carbide fibers with controllable crystal phase ratio and the application of the synthesized molybdenum carbide fibers in the electrolysis of seawater.

[0017] The present invention uses cheap polymers or metal molybdenum sources as raw materials, and only requires annealing reaction under air conditions or inert gas conditions to obtain one-dimensional molybdenum carbide nanomaterials with continuous and precisely controlled crystal phase ratios. The cheap raw materials and simple and convenient operation are conducive to the large-scale preparation of the material.

[0018] The molybdenum carbide crystal phase control mechanism involved in the present invention is based on the regulation of the relative contents of carbon source and molybdenum source to cause changes in reducing ability, thereby realizing the controlled preparation of molybdenum carbide with different crystal phases. The preparation conditions are controlled so that when the reducing ability is strong (high carbon: molybdenum ratio), metastable α-MoC is preferentially obtained; the preparation conditions are controlled so that when the reducing ability is strong, β-Mo2C is obtained when the reducing ability is weak (low carbon: molybdenum ratio); the preparation conditions are controlled so that the reducing ability is kept within an appropriate range (appropriate carbon: molybdenum ratio), and a mixture of metastable α-MoC and stable β-Mo2C in any proportion is obtained. The control principle diagram of the mutual transformation of metastable α-MoC and stable β-Mo2C is shown in the figure. Figure 1 shown.

[0019] Compared with the prior art, the present invention has the following beneficial effects:

[0020] 1) The use of noble metal catalysts is avoided in the entire preparation process, which reduces the use cost and obtains a molybdenum carbide material that does not contain noble metals (or other catalysts);

[0021] 2) Avoiding the combined use of reducing gas or small molecule carbon source gas molecules, thereby improving the safety of the preparation process;

[0022] 3) The method of the present invention can achieve the preparation of two crystalline phases of molybdenum carbide materials in different ratios. It can obtain both the difficult-to-prepare metastable α-MoC and the β-Mo2C crystalline phase, or prepare molybdenum carbide materials in any ratio of the two phases as required, providing a simple and efficient source for research and production in other fields. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 This is a control principle diagram of the mutual transformation between the metastable α-MoC and the stable β-Mo2C phases of the present invention.

[0024] Figure 2 1 and 2 are scanning electron microscope images of the polymer fiber membrane prepared in Example 1 of the present invention, wherein a) is a scanning electron microscope image at a higher magnification, and b) is a scanning electron microscope image at a lower magnification.

[0025] Figure 3 3 is the thermogravimetric curve of the polymer fiber membrane prepared in the embodiment of the present invention.

[0026] Figure 4 1 is the X-ray diffraction pattern of the molybdenum carbide material prepared in Examples 1-6 of the present invention.

[0027] Figure 5 1 is the X-ray diffraction pattern of the molybdenum carbide materials prepared in Examples 7-10 and Example 1 of the present invention.

[0028] Figure 6 1 and 2 are X-ray diffraction patterns of the molybdenum carbide materials prepared in Examples 11-12 and 1 of the present invention.

[0029] Figure 7 1 is a scanning electron microscope photograph of the molybdenum carbide material prepared in Example 1 of the present invention.

[0030] Figure 8 3 is a scanning electron microscope photograph of the molybdenum carbide material prepared in Example 6 of the present invention.

[0031] Figure 9 The β-Mo2C obtained in Example 6 of the present invention was used as a raw material to carry out a cycle performance test of the electrolysis of seawater. DETAILED DESCRIPTION

[0032] In order to enable those skilled in the art to better understand the technical solutions of the present invention, the technical solutions in the embodiments of the present invention are clearly and completely described below. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative work should fall within the scope of protection of the present invention.

[0033] Example 1

[0034] The polymer fiber membrane is prepared by electrospinning, as follows:

[0035] 1) Dissolve polyacrylonitrile (1.0 g) and molybdenum acetylacetonate (1.0 g) in N,N-dimethylformamide (10 mL) and stir to form a yellow transparent solution, which is used as the spinning solution;

[0036] 2) The spinning solution was prepared into a fiber membrane using an electrospinning method. The electrospinning high voltage was 16KV, the distance between the tip of the electrospinning and the collection device was 18cm, the electrospinning time was 10 hours, and the propulsion speed of the spinning solution was 1mL / hour. After the electrospinning was completed, a light yellow polymer membrane was generated. The polymer membrane was placed in a 60°C oven and dried overnight to remove the residual solvent, and finally a uniform and soft polymer fiber membrane was obtained. The scanning electron microscope image of the polymer fiber membrane is shown below. Figure 2 As shown in the figure, the sample is in obvious one-dimensional fiber shape, evenly distributed, and free of other impurities; the thermogravimetric analysis results of the polymer fiber membrane are shown in Figure 3 As shown in the figure, after 260°C, as the pre-oxidation temperature increases, the carbon-containing functional groups on the polymer are oxidized by air and gradually lose weight, resulting in a decrease in carbon content. That is, as the pre-oxidation temperature gradually increases, the carbon content gradually decreases and the ability of carbon thermal reduction gradually decreases.

[0037] 3) Under air conditions, the temperature was raised at a rate of 5°C / min and the temperature was set at 260°C for pre-oxidation for 2 hours. In an inert gas argon atmosphere, the temperature was raised at a rate of 5°C / min and the temperature was set at 800°C for high temperature annealing for 2 hours to obtain a molybdenum carbide material composed of a metastable α-MoC phase. The scanning electron microscope image of the molybdenum carbide material is shown in the figure below. Figure 7 As shown in the figure, even after pre-oxidation and carbonization annealing treatment, the fiber morphology can be maintained and no obvious agglomeration occurs, indicating that the carbide obtained in this process is uniform and stable.

[0038] Example 2

[0039] The difference from Example 1 is that the pre-oxidation temperature in step 3) is 310° C., and the remaining preparation processes and steps are the same as those in Example 1.

[0040] Example 3

[0041] The difference from Example 1 is that the pre-oxidation temperature in step 3) is 340° C., and the remaining preparation processes and steps are the same as those in Example 1.

[0042] Example 4

[0043] The difference from Example 1 is that the pre-oxidation temperature in step 3) is 345° C., and the remaining preparation processes and steps are the same as those in Example 1.

[0044] Example 5

[0045] The difference from Example 1 is that the pre-oxidation temperature in step 3) is 350° C., and the remaining preparation processes and steps are the same as those in Example 1.

[0046] Example 6

[0047] The difference from Example 1 is that the pre-oxidation temperature in step 3) is 360°C, and the rest of the preparation process and steps are the same as in Example 1. The scanning electron microscope image of the product is as follows Figure 8 As shown, even after a pre-oxidation treatment at a higher temperature (the same carbonization treatment as in Example 1), the fiber morphology can be maintained without obvious agglomeration, indicating that the carbide obtained in this treatment process is uniform and stable.

[0048] The molybdenum carbide materials obtained in Examples 1-6 were analyzed by X-ray diffraction, and the results were as follows: Figure 4 As shown, in Example 1, under the condition of 260°C, a molybdenum carbide material composed entirely of the metastable α-MoC phase was obtained. In Examples 2-5, as the pre-oxidation temperature increased, the proportion of the α-MoC phase gradually decreased, and the proportion of the β-Mo2C phase gradually increased, until the pre-oxidation treatment at 360°C in Example 6 obtained a molybdenum carbide material composed entirely of the β-Mo2C phase. In Examples 2-5, a mixed phase of the α-MoC phase and the β-Mo2C phase was obtained in the temperature range greater than 260°C and less than 360°C. Therefore, by selecting the pre-oxidation temperature within the temperature range greater than 260°C and less than 360°C, the synthesis of one-dimensional molybdenum carbide fibers with any proportion of the two crystal phases can be achieved.

[0049] Example 7

[0050] The difference from Example 1 is that step 1) is to dissolve polyacrylonitrile (1.0 g) and molybdenum acetylacetonate (0.5 g) in N,N-dimethylformamide (10 mL), stir evenly to form a yellow transparent solution, which is used as a spinning solution; the rest of the preparation process and steps are the same as Example 1.

[0051] Example 8

[0052] The difference between Example 1 is that step 1) is to dissolve polyacrylonitrile (1.0 g) and molybdenum acetylacetonate (1.5 g) in N,N-dimethylformamide (10 mL), stirring to form a yellow transparent solution, as a spinning solution ready; the rest of the preparation process and steps are the same as Example 1.

[0053] Example 9

[0054] The difference between Example 1 is that step 1) is to dissolve polyacrylonitrile (1.0 g) and molybdenum acetylacetonate (2.0 g) in N,N-dimethylformamide (10 mL), stirring to form a yellow transparent solution, as a spinning solution ready; the rest of the preparation process and steps are the same as Example 1.

[0055] Example 10

[0056] The difference between Example 1 is that step 1) is to dissolve polyacrylonitrile (1.0 g) and molybdenum acetylacetonate (3.0 g) in N,N-dimethylformamide (10 mL), stirring to form a yellow transparent solution, as a spinning solution ready; the rest of the preparation process and steps are the same as Example 1.

[0057] The carbonized molybdenum material obtained in Examples 7-10 and Example 1 was analyzed by X-ray diffraction, and the results are shown in Figure 5 As shown in the figure, at low molybdenum acetylacetonate content of 0.5 g (Example 7) and 1 g (Example 1), the carbonized molybdenum material is composed of a metastable phase α-MoC phase, with the proportion of α-MoC phase gradually decreasing and the proportion of β-Mo2C phase gradually increasing as the molybdenum acetylacetonate content increases, until the fiber membrane with 3 g (Example 10) of molybdenum acetylacetonate content, a single-phase β-Mo2C composed of carbonized molybdenum material is obtained. In the above selected molybdenum acetylacetonate mass range greater than 0.5 g and less than 3 g, adjusting the mass of the metal molybdenum source can also achieve the synthesis of one-dimensional carbonized molybdenum fiber with any proportion of crystal phase.

[0058] Example 11

[0059] The metastable phase α-MoC phase composed of carbonized molybdenum material prepared in Example 1 was used as raw material, and then subjected to post-oxidation treatment at a temperature of 180°C for 2h, and after cooling to room temperature, a sample was obtained; in an inert gas argon atmosphere, the above sample was subjected to carbonization annealing treatment at 800°C for 2h, and a carbonized molybdenum material was obtained.

[0060] Example 12

[0061] The molybdenum carbide material composed of the metastable α-MoC phase prepared in Example 1 was used as a raw material, and then subjected to a post-oxidation treatment at a temperature of 310°C for 2 hours, and then cooled to room temperature to obtain a sample; in an atmosphere of inert gas argon, the above sample was subjected to a carbonization annealing treatment at 800°C for 2 hours to obtain a molybdenum carbide material.

[0062] The molybdenum carbide fibers obtained in Example 11 and Example 12 were subjected to X-ray diffraction analysis. Figure 6 As shown in the figure, the proportion of the β-Mo2C phase increases with the increase of the post-oxidation temperature. Under the post-oxidation condition of 310℃, a molybdenum carbide material composed entirely of the β-Mo2C phase is obtained. Therefore, setting the post-oxidation temperature between room temperature and 310℃ can indirectly achieve the synthesis of one-dimensional molybdenum carbide fibers with any ratio of the two crystal phases.

[0063] Example 13

[0064] The β-Mo2C phase molybdenum carbide obtained in Example 6 was used as raw material to conduct seawater electrolysis test, and the raw material was cut into 0.5×0.5 cm 2 The electrode was provided and tested under alkaline natural seawater conditions using a standard three-electrode system in the electrolytic cell, using a carbon rod as the counter electrode and a mercury / mercuric oxide electrode as the reference electrode.

[0065] An electrochemical workstation was used as a detection and recording device, and linear sweep voltammetry was used to detect the material properties. The initial voltage was set to -0.6V, the end voltage was -1.6V, and the sweep rate was 2mV / s. The working curve was recorded. Cyclic voltammetry was used to detect and evaluate the stability of the material. Within the above voltage range, the sweep rate was 100mV / s. After the cycle was completed, the linear sweep voltammetry was used again to test and evaluate the reacted material, and the working curve was recorded. The results are shown in Figure 2. Figure 9 After 2000 cycles of stability testing, the performance of β-Mo2C as a catalyst remained almost unchanged even under harsh alkaline seawater conditions, indicating that β-Mo2C has good catalytic activity and stability in the electrocatalytic hydrogen production reaction in natural seawater.

[0066] Although the present invention has been described in detail with reference to preferred embodiments, the present invention is not limited thereto. Without departing from the spirit and substance of the present invention, persons of ordinary skill in the art may make various equivalent modifications or substitutions to the embodiments of the present invention, and such modifications or substitutions are intended to fall within the scope of the present invention. Therefore, the scope of protection of the present invention shall be subject to the scope of protection of the claims.

Claims

1. A method for synthesizing one-dimensional molybdenum carbide fibers with controllable crystal phase ratio, characterized in that: A carbon source and a molybdenum source are dissolved in a solvent to form a spinning solution, which is then prepared into a fiber membrane through a spinning method and pre-oxidized in air or oxygen. A carbon thermal reduction reaction then occurs in an inert atmosphere to form molybdenum carbide with different crystal structures by controlling the reducing ability of the carbon source on the molybdenum source. The carbon source is a high molecular weight polymer. The molybdenum source is one of ammonium molybdate, sodium molybdate, molybdic acid, molybdenum acetylacetonate, molybdenum powder and molybdenum oxide; Different crystal structures include one phase or a mixed structure of two phases of metastable α-MoC and stable β-Mo2C; Controlling the reducing ability of the carbon source to the molybdenum source includes adjusting the relative contents of the carbon source and the molybdenum source and the pre-oxidation temperature, specifically: (1) When the mass ratio of carbon source to molybdenum source is greater than or equal to 1:1: When the pre-oxidation temperature is less than or equal to 260°C, a metastable α-MoC phase is obtained; when the pre-oxidation temperature is greater than or equal to 360°C and less than 600°C, a stable β-Mo2C phase is obtained; when the pre-oxidation temperature is greater than or equal to 360°C and less than 600°C, a stable β-Mo2C phase is obtained; (2) When the pre-oxidation temperature is 260°C: When the mass ratio of carbon source to molybdenum source is less than or equal to 1:3, a stable β-Mo2C phase is obtained; when the mass ratio of carbon source to molybdenum source is greater than 1:3 and less than 1:1, a mixed phase of metastable α-MoC and stable β-Mo2C is obtained; Controlling the reducing ability of the carbon source on the molybdenum source also includes post-oxidation treatment, specifically: using the metastable α-MoC phase to post-treat to obtain a stable β-Mo2C phase and a mixed phase of the metastable α-MoC and stable β-Mo2C phases; when the post-oxidation temperature is between room temperature and 310°C, a mixed phase of the metastable α-MoC and stable β-Mo2C phases is obtained; when the post-oxidation temperature is greater than 310°C, a stable β-Mo2C phase is obtained; Pre-oxidation is to anneal the fiber membrane in air or oxygen at a heating rate of 0.5-20°C / min for 0.5-20 hours; The carbon thermal reduction reaction is carried out by annealing in an inert atmosphere at a rate of 0.5-20°C / min to 600-1200°C for 1-12 hours; The high molecular polymer is one or a mixture of polyacrylonitrile, polyvinyl pyrrolidone, polyvinyl alcohol or polylactic acid; The solvent is one or a mixture of N,N-dimethylformamide, water, ethanol and chloroform; The high voltage applied during spinning is 8-30KV, the distance between the spinning tip and the collecting device is 8-30cm, and the spinning time is 2-50 hours; after the spinning is completed, a polymer film is obtained.

2. Use of the molybdenum carbide fiber synthesized by the synthesis method as claimed in claim 1 in the electrolysis of seawater.

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