A ZIF-MOG-derived composite nanocarbon fiber catalyst and its preparation method and application

Abstract

The present invention belongs to the field of battery technology and provides a ZIF-MOG derived composite nano-carbon fiber catalyst and its preparation method and application. The method of the present invention comprises: reacting dimethylimidazole, a metal salt and an organic solvent to obtain ZIF-67; mixing a metal salt, a nitrogen-containing component, resorcinol and water, sequentially adding formaldehyde and ammonia water, reacting to form a metal organic gel; mixing ZIF-67, MOG, a nanofiber polymer and a solvent, and performing high-temperature carbonization after electrostatic spinning. The present invention utilizes electrostatic spinning to achieve co-doping of ZIF-67 and MOG on microscopic nanofibers, giving play to their respective structural performance advantages, so that the specific surface area and electronic conductivity of the material are greatly improved, and different structures and active centers synergistically improve the electrical conductivity, electrochemical stability, thermal stability and redox bifunctional catalytic activity of the material itself, thereby improving the power density and energy efficiency of the battery.

Description

Technical Field

[0001] The present invention relates to the technical field of batteries, and in particular to a ZIF-MOG derived composite nano-carbon fiber catalyst and a preparation method and application thereof. Background Art

[0002] Zinc-air batteries (ZABs) are primary cells that use oxygen from air as the positive electrode active material, zinc as the negative electrode, and a neutral or alkaline solution as the electrolyte. Due to their high theoretical specific capacity density, safety, pollution-free operation, simple structure, abundant zinc resources, and low cost, they have attracted considerable attention in the field of novel energy storage. However, during the charge and discharge process of ZABs, the slow kinetics of the oxygen reduction reaction (ORR) and the high potential of the oxygen evolution reaction (OER) have hindered their industrial development. Therefore, it is particularly important to select suitable bifunctional cathode catalysts to increase the ORR reaction rate and reduce the overpotential of the OER reaction.

[0003] Zeolitic imidazole framework (ZIF-67) has the advantages of high specific surface area, rich porosity, easy functionalization, and high crystallinity. Its high porosity provides ample space and channels for the adsorption, storage, and transport of substances. Furthermore, the metal ions and organic ligands (dimethylimidazole) in ZIF-67 are connected by strong coordination bonds. Its unique structure and electronic properties exhibit excellent ORR catalytic activity in catalytic reactions.

[0004] Metal-organic gel (MOG), a novel polymer composite material, has been extensively studied in the field of electrocatalysis due to its high specific surface area, excellent thermal stability, controllability, and high yield. MOG possesses a three-dimensional network structure, which gives it a high specific surface area and abundant nanopores. This structure also makes it highly susceptible to doping. Catalytic materials with specific compositions and structures can be prepared to meet the needs of different catalytic reactions, demonstrating excellent controllability and catalytic activity.

[0005] PAN-based carbon nanofibers prepared by electrospinning possess properties such as large surface area and rich porosity, which facilitate efficient electron transfer. Therefore, integrating composite electrode materials into highly conductive carbon nanofibers through electrospinning can achieve a stable, orderly, and uniform distribution of multiple catalytically active centers. Leveraging the synergistic catalytic effects of the microscopic active centers in each material can improve the charge exchange efficiency and stability of the composite electrode material during redox cycling, thereby enhancing its electrochemical performance, which is of great value. Summary of the Invention

[0006] The purpose of the present invention is to provide a ZIF-MOG derived composite nano-carbon fiber catalyst and its preparation method and application in order to overcome the deficiencies of the prior art.

[0007] In order to achieve the above-mentioned object of the invention, the present invention provides the following technical solutions:

[0008] The present invention provides a method for preparing a ZIF-MOG-derived composite nanocarbon fiber catalyst, comprising the following steps:

[0009] 1) mixing dimethylimidazole, a metal salt, and an organic solvent and reacting them to obtain ZIF-67;

[0010] 2) mixing the metal salt, the nitrogen-containing component, resorcinol and water to obtain a mixed solution, and sequentially adding formaldehyde and ammonia water to the mixed solution to react and form a metal organic gel;

[0011] 3) mixing ZIF-67, metal organic gel, nanofiber polymer and solvent to obtain a spinning solution;

[0012] 4) The spinning solution is electrospun and dried sequentially to obtain nanofibers;

[0013] 5) The nanofibers are sequentially subjected to high-temperature carbonization and refinement treatments to obtain ZIF-MOG derived composite nanocarbon fiber catalysts.

[0014] Preferably, the organic solvent in step 1) is ethanol, N,N-dimethylformamide or methanol, and the metal salt is an iron salt, a cobalt salt, a nickel salt, a copper salt or a zinc salt;

[0015] The molar ratio of the metal salt to dimethylimidazole is 1:8-80, and the molar ratio of dimethylimidazole to the organic solvent is 1:16-160;

[0016] The reaction temperature is 15 to 80° C., and the reaction time is 2 to 48 hours.

[0017] Preferably, the metal salt in step 2) is an iron salt, a cobalt salt, a nickel salt, a copper salt or a zinc salt; and the nitrogen-containing component is peptone, melamine, urea or chitosan;

[0018] The reaction time is 5 to 120 minutes, the reaction temperature is 30 to 140° C. Ammonia water is added to adjust the pH value of the system to 7 to 14.

[0019] Preferably, in step 2), the molar ratio of the metal salt, the nitrogen-containing component and resorcinol is 1:1-10:20-200, the molar ratio of resorcinol to formaldehyde is 1:1-3, and the molar ratio of resorcinol to water is 1:25-30.

[0020] Preferably, in step 3), the nanofiber polymer comprises polyacrylonitrile, polyvinyl pyrrolidone, polyvinyl alcohol, polystyrene or polymethyl methacrylate; the molecular weight of polyacrylonitrile is 50,000 to 300,000, and the solvent comprises water, N,N-dimethylformamide, methanol or ethanol;

[0021] The mixing temperature is 20-100° C., and the mixing time is 6-96 hours.

[0022] Preferably, in step 3), the mass ratio of ZIF-67 to the metal organic gel is 1-100:1-100, and the mass ratio of the total mass of ZIF-67 and the metal organic gel to the nanofiber polymer is 1-10:1-10.

[0023] Preferably, the electrospinning process parameters of step 4) are: the voltage of the needle is 5 to 50 kV, the injection rate is 0.1 to 10 mL / h, the collection speed is 200 to 1000 rpm, the round-trip distance is 60 to 180 mm, the spinning temperature is 10 to 50 ° C, and the spinning humidity is 10 to 60% RH; the drying temperature is 40 to 100 ° C, and the drying time is 2 to 48 h.

[0024] Preferably, the temperature of the high-temperature carbonization in step 5) is 650-1200°C, the time of the high-temperature carbonization is 1-12h, and the heating rate of the high-temperature carbonization is 2-15°C / min; the high-temperature carbonization is carried out under a protective gas atmosphere, and the flow rate of the protective gas is 10-200mL / min.

[0025] The present invention also provides a ZIF-MOG derived composite nano-carbon fiber catalyst prepared by the preparation method.

[0026] The present invention also provides the use of the ZIF-MOG derived composite nano-carbon fiber catalyst in a battery, wherein the battery is a battery in which oxygen participates in the cathode reaction.

[0027] The beneficial effects of the present invention include the following:

[0028] 1) The ZIF-MOG-derived composite carbon fiber material prepared by the present invention has excellent electrocatalytic activity and stability. The present invention utilizes electrospinning technology to achieve the synergistic construction of ZIF-67 and MOG-derived composite carbon fiber material. The multi-active center synergistic catalysis accelerates the kinetics of oxygen reduction while reducing the overpotential of the oxygen evolution reaction. After long-term charge and discharge cycles, the voltage range remains stable with no significant attenuation. The ZIF-MOG-derived composite carbon fiber material prepared by the present invention has excellent bifunctional catalytic activity and stability, is environmentally friendly, and has broad development prospects.

[0029] 2) The present invention utilizes a chemical reaction between metal ions and organic ligands to prepare a precursor ZIF-67 with excellent performance and high porosity in a relatively simple manner. The ZIF-67 material has advantages such as excellent electrochemical stability. The present invention utilizes the condensation reaction between resorcinol and formaldehyde to prepare MOG with large yield and excellent performance. At the same time, its electrocatalytic activity is further improved by doping with metal ions and nitrogen sources.

[0030] 3) The present invention utilizes electrospinning to achieve co-doping of ZIF-67 and MOG on microscopic nanofibers, leveraging their respective structural and performance advantages to significantly increase the material's specific surface area and electronic conductivity. The different structures and active centers synergistically improve the material's electrical conductivity, electrochemical stability, thermal stability, and redox bifunctional catalytic activity, further enhancing the power density and energy efficiency of batteries with oxygen in the cathode reaction. Furthermore, during the high-temperature carbonization of the nanofibers, the high-temperature decomposition of urea, chitosan, and peptone provides a nitrogen source for the catalyst itself, further enhancing the catalytic activity of the ZIF-MOG-derived composite carbon fiber material.

[0031] 4) The electrospinning technology of the present invention has the advantages of simple equipment operation, easy availability of materials, extremely low operational risk factor, high production efficiency, diverse collection methods, high equipment flexibility, small footprint, and easy satisfaction of experimental conditions. By adjusting the parameters, nanofibers with high fineness can be easily obtained. It is also easy to compound with other materials, which has great advantages.

[0032] 5) The present invention leverages the inherent performance advantages of ZIF-67 and MOG, connecting them in series using PAN-based nanocarbon fibers. This optimizes the spatial distribution of ZIF-67 and MOG particles while exposing more electrocatalytically active sites. The presence of the nanofibers also increases the electrical conductivity of the catalyst, further enhancing its electrocatalytic activity. This invention addresses the problems of insufficient catalytic activity and poor long-term cycling stability associated with single ZIF-67 and MOG-derived materials, thereby potentially further resolving existing issues such as low surface activity and insufficient electrocatalytic activity of electrode materials at the cathode of batteries where oxygen participates in the cathode reaction. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 ORR and LSV polarization curves of ZMCF-1 of Example 1, ZIF-67 and Pt / C of Comparative Example 1 in 0.1 mol / L KOH solution;

[0034] Figure 2 OER polarization curves of ZMCF-1 of Example 1, ZIF-67 and RuO2 of Comparative Example 1 in 1 mol / L KOH solution;

[0035] Figure 3 The discharge polarization curve and power density diagram of the zinc-air battery assembled with ZMCF-1 and Pt / C as cathode catalysts in Example 1 respectively;

[0036] Figure 4 The ZMCF-1 of Example 1 was used as the cathode catalyst to assemble the zinc-air battery and the Pt / C-RuO2 battery at 10 mA / cm 2 Constant current charge and discharge curve under ;

[0037] Figure 5 ORR and LSV polarization curves of ZMCF-2 and Pt / C in 0.1 mol / L KOH solution of Example 2;

[0038] Figure 6 This is the OER polarization curve of ZMCF-2 and RuO2 in 1 mol / L KOH solution of Example 2. DETAILED DESCRIPTION

[0039] The present invention provides a method for preparing a ZIF-MOG-derived composite nanocarbon fiber catalyst, comprising the following steps:

[0040] 1) mixing dimethylimidazole, a metal salt, and an organic solvent and reacting them to obtain ZIF-67;

[0041] 2) mixing the metal salt, the nitrogen-containing component, resorcinol and water to obtain a mixed solution, and sequentially adding formaldehyde and ammonia water to the mixed solution to react and form a metal organic gel;

[0042] 3) mixing ZIF-67, metal organic gel, nanofiber polymer and solvent to obtain a spinning solution;

[0043] 4) The spinning solution is electrospun and dried sequentially to obtain nanofibers;

[0044] 5) The nanofibers are sequentially subjected to high-temperature carbonization and refinement treatments to obtain ZIF-MOG derived composite nanocarbon fiber catalysts.

[0045] In the present invention, the organic solvent in step 1) is preferably ethanol, N,N-dimethylformamide or methanol, and the metal salt is preferably an iron salt, a cobalt salt, a nickel salt, a copper salt or a zinc salt;

[0046] The molar ratio of the metal salt to dimethylimidazole is preferably 1:8-80, more preferably 1:12-70, more preferably 1:20-60, and the molar ratio of dimethylimidazole to the organic solvent is preferably 1:16-160, more preferably 1:25-140, more preferably 1:35-100;

[0047] The reaction temperature is preferably 15 to 80° C., more preferably 25 to 70° C., and more preferably 35 to 60° C.; the reaction time is preferably 2 to 48 h, more preferably 5 to 40 h, and more preferably 10 to 30 h.

[0048] In the present invention, in step 1), the mixing is preferably performed by first dissolving dimethylimidazole in an organic solvent to obtain a mixed solution, and then adding the metal salt to the mixed solution; the dissolution time is preferably 5 to 60 minutes, more preferably 10 to 50 minutes, and more preferably 20 to 40 minutes; after the reaction is completed, impurities are removed and dried in sequence to obtain ZIF-67; the impurity removal method is preferably centrifugal washing; the drying temperature is preferably 40 to 200°C, more preferably 50 to 180°C, and more preferably 80 to 150°C; the drying time is preferably 8 to 72 hours, more preferably 10 to 70 hours, and more preferably 15 to 65 hours; and the drying is performed in a blast drying oven or a vacuum drying oven.

[0049] In the present invention, the dimethylimidazole (2-MIM) in step 1) is an organic ligand, the metal salt provides metal ions, and the organic solvent provides a reaction medium. During the reaction, the metal ions combine with the organic ligand to synthesize ZIF-67.

[0050] In the present invention, the metal salt in step 2) is preferably an iron salt, a cobalt salt, a nickel salt, a copper salt or a zinc salt; the nitrogen-containing component is preferably peptone, melamine, urea or chitosan;

[0051] The reaction time is preferably 5 to 120 min, more preferably 10 to 110 min, more preferably 20 to 100 min, and the reaction temperature is preferably 30 to 140° C., more preferably 40 to 100° C., more preferably 50 to 80° C. Ammonia water is added to adjust the pH value of the system to preferably 7 to 14, more preferably 8 to 13, more preferably 9 to 12.

[0052] In the present invention, the molar ratio of the metal salt, the nitrogen-containing component and resorcinol in step 2) is preferably 1:1-10:20-200, more preferably 1:2-9:30-180, more preferably 1:3-7:40-160, the molar ratio of resorcinol to formaldehyde is preferably 1:1-3, more preferably 1:1.5-2.5, more preferably 1:2, and the molar ratio of resorcinol to water is preferably 1:25-30, more preferably 1:26-28, more preferably 1:27.

[0053] In the present invention, after the reaction in step 2) is completed, drying and grinding are carried out in sequence to obtain the metal organic gel; the drying temperature is preferably 40 to 135°C, more preferably 60 to 120°C, and more preferably 80 to 110°C, and the drying time is preferably 2 to 10 days, more preferably 3 to 9 days, and more preferably 5 to 8 days.

[0054] In the present invention, the nanofiber polymer in step 3) preferably comprises polyacrylonitrile (PAN), polyvinyl pyrrolidone (PVP), polyvinyl alcohol (PVA), polystyrene (PS) or polymethyl methacrylate (PMMA); the molecular weight of polyacrylonitrile is preferably 50,000 to 300,000, more preferably 80,000 to 250,000, and more preferably 100,000 to 200,000, and the solvent preferably comprises water, N,N-dimethylformamide, methanol or ethanol;

[0055] The mixing temperature is preferably 20-100° C., more preferably 30-90° C., more preferably 40-80° C., and the mixing time is preferably 6-96 h, more preferably 16-90 h, more preferably 24-80 h. The mixing is preferably performed by magnetic stirring or ultrasonic oscillation.

[0056] In the present invention, the mass ratio of ZIF-67 and metal organic gel in step 3) is preferably 1-100:1-100, more preferably 1-80:1-80, and more preferably 1-40:1-40; the mass ratio of the total mass of ZIF-67 and metal organic gel to the nanofiber polymer is preferably 1-10:1-10, more preferably 1-8:1-8, and more preferably 1-5:1-5.

[0057] In the present invention, the process parameters of the electrospinning in step 4) are: the voltage of the needle is preferably 5 to 50 kV, more preferably 10 to 40 kV, more preferably 15 to 35 kV, the injection rate is preferably 0.1 to 10 mL / h, more preferably 0.5 to 9 mL / h, more preferably 1 to 8 mL / h, the collection speed is preferably 200 to 1000 rpm, more preferably 300 to 800 rpm, more preferably 400 to 700 rpm, the round trip distance is preferably 60 to 180 mm, more preferably The spinning temperature is preferably 10-50°C, more preferably 15-40°C, more preferably 20-30°C, and the spinning humidity is preferably 10-60% RH, more preferably 20-50% RH, more preferably 30-40% RH; the drying temperature is preferably 40-100°C, more preferably 50-90°C, more preferably 60-80°C, and the drying time is preferably 2-48h, more preferably 5-40h, more preferably 12-35h.

[0058] In the present invention, the temperature of the high-temperature carbonization in step 5) is preferably 650-1200°C, more preferably 750-1100°C, more preferably 850-1000°C, the time of high-temperature carbonization is preferably 1-12h, more preferably 3-10h, more preferably 5-8h, the heating rate of high-temperature carbonization is preferably 2-15°C / min, more preferably 3-12°C / min, more preferably 5-10°C / min; the high-temperature carbonization is preferably carried out under a protective gas atmosphere, and the flow rate of the protective gas is preferably 10-200mL / min, more preferably 20-180mL / min, and preferably 50-150mL / min.

[0059] In the present invention, the refinement treatment in step 5) is grinding and high-energy ball milling.

[0060] The present invention also provides a ZIF-MOG derived composite nano-carbon fiber catalyst prepared by the preparation method.

[0061] The present invention also provides the use of the ZIF-MOG derived composite nano-carbon fiber catalyst in a battery, wherein the battery is a battery in which oxygen participates in the cathode reaction.

[0062] In the present invention, the battery in which oxygen participates in the cathode reaction is preferably a zinc-air battery or a hydrogen-oxygen fuel cell.

[0063] The present invention utilizes electrospinning technology to assemble previously prepared ZIF-67 particles and MOG particles in series via PAN-based carbon fibers, and then undergoes high-temperature carbonization and other treatments to obtain ZIF-MOG-derived composite carbon fiber (ZMCF) materials. The specific process is as follows: first, ZIF-67 particles with excellent catalytic activity are synthesized through a self-assembly reaction of metal ions and organic ligands, deprotonation of the organic ligands, coordination of metal ions with ligands, and self-assembly to form a framework structure; then, a polycondensation reaction of resorcinol and formaldehyde is performed, and metal ions and a nitrogen source are incorporated. After aging, MOG particles with high yield and excellent performance are obtained. The above two substances are used as precursors to prepare a spinning solution, and a composite carbon fiber material is prepared by electrospinning. Finally, the resulting electrode material is subjected to high-temperature carbonization in a protective gas atmosphere using a high-temperature tube furnace at a temperature of 650-1200°C. During the carbonization process, the nitrogen-containing components are decomposed at high temperature to replenish the nitrogen source for the nanofibers themselves. Finally, the resulting nanocarbon fibers are ground and subjected to high-energy ball milling. The ZIF-MOG-derived composite carbon fiber material prepared by the present invention has effectively improved its catalytic effect on oxygen reduction (ORR) and oxygen evolution (OER) reactions. From the charge and discharge tests of the battery assembled with it, its power density and long-term cycle capacity have been improved, showing excellent bifunctional catalytic activity, and can be used for the preparation and research of battery positive electrode materials.

[0064] The technical solutions provided by the present invention are described in detail below with reference to the embodiments, but they should not be construed as limiting the scope of protection of the present invention.

[0065] Example 1

[0066] Dissolve dimethylimidazole in N,N-dimethylformamide and stir for 10 minutes. Then, add cobalt nitrate hexahydrate to the mixture and stir with magnetic stirring at 25°C for 2 hours. The molar ratio of cobalt nitrate hexahydrate to dimethylimidazole is 1:8, and the molar ratio of dimethylimidazole to N,N-dimethylformamide is 1:16. The mixture is then washed and centrifuged to remove impurities, then dried in a vacuum oven at 80°C for 12 hours. Once cooled to room temperature, ZIF-67 is ground and used for later use.

[0067] Cobalt nitrate hexahydrate, resorcinol, and peptone were dissolved in deionized water and magnetically stirred for 10 minutes to allow the solid to slowly dissolve. Subsequently, formaldehyde was slowly added to the mixed solution and stirred for 0.5 hours. The molar ratio of cobalt nitrate hexahydrate, peptone, and resorcinol was 1:1:20, the molar ratio of resorcinol to deionized water was 1:27, and the molar ratio of resorcinol to formaldehyde was 1:2. Ammonia (AR, mass concentration 26%) was slowly added dropwise to the mixed solution in a 60°C water bath to adjust the solution pH to 7. The solution was stirred for 10 minutes to form an organogel. Finally, the mixture was placed in a vacuum drying oven (vacuum degree 133 Pa) and vacuum dried at 80°C for 4 days. The resulting solid was ground to obtain a metal organic gel (MOG).

[0068] The ground ZIF-67, MOG, and polyacrylonitrile (molecular weight of 100,000) were added to N,N-dimethylformamide (N,N-dimethylformamide). The mass ratio of ZIF-67 to MOG was 1:1, and the mass ratio of the total mass of ZIF-67 and MOG to polyacrylonitrile was 1:2. The mixed solution was magnetically stirred at 20°C for 24 hours to obtain a uniform spinning solution.

[0069] 5 mL of spinning solution was placed in a 10 mL syringe and electrospun to produce electrospun nanofibers. The electrospinning parameters were: needle voltage of 13 kV, injection rate of 1 mL / h, collection speed of 450 rpm, round-trip distance of 120 mm, spinning temperature of 24°C, and spinning humidity of 10% RH. The electrospun nanofibers were then dried in a vacuum oven at 80°C for 12 hours to obtain the nanofibers.

[0070] The nanofibers were carbonized in a high-temperature tube furnace under an inert N2 atmosphere (N2 flow rate of 40 mL / min). 3 g of urea was placed in an ark at the inlet of the tube furnace and heated to 800°C at a heating rate of 5°C / min. Carbonization was then performed at 800°C for 2 hours. After carbonization, the resulting carbon nanocomposite was ground and subjected to high-energy ball milling to obtain the ZIF-MOG-derived composite nanocarbon fiber catalyst (ZMCF-1).

[0071] Example 2

[0072] The mass ratio of ZIF-67 to MOG in Example 1 was changed to 1:20, and other conditions were the same as in Example 1 to obtain a ZIF-MOG-derived composite nanocarbon fiber catalyst (ZMCF-2).

[0073] Example 3

[0074] Dissolve dimethylimidazole in N,N-dimethylformamide and stir for 20 minutes. Then, add ferric nitrate nonahydrate to the mixture and stir with magnetic stirring at 18°C ​​for 6 hours. The molar ratio of ferric nitrate nonahydrate to dimethylimidazole is 1:12, and the molar ratio of dimethylimidazole to N,N-dimethylformamide is 1:48. The mixture is then washed and centrifuged to remove impurities, then dried in a vacuum oven at 40°C for 8 hours. Once cooled to room temperature, ZIF-67 is ground and used for later use.

[0075] Ferric nitrate nonahydrate, resorcinol, and peptone were dissolved in deionized water and magnetically stirred for 15 minutes to allow the solid to slowly dissolve. Subsequently, formaldehyde was slowly added to the mixed solution and stirred for 1 hour. The molar ratio of ferric nitrate nonahydrate, peptone, and resorcinol was 1:3:30, the molar ratio of resorcinol to deionized water was 1:27, and the molar ratio of resorcinol to formaldehyde was 1:2. Ammonia (AR, mass concentration: 27%) was slowly added dropwise to the mixed solution in a 30°C water bath to adjust the solution pH to 8. The solution was stirred for 40 minutes to form an organogel. Finally, the mixture was placed in a vacuum drying oven (vacuum pressure of 133 Pa) and vacuum dried at 50°C for 6 days. The resulting solid was ground to obtain a metal organic gel (MOG).

[0076] The ground ZIF-67, MOG, and polyvinyl pyrrolidone were added to N,N-dimethylformamide (NDM). The mass ratio of ZIF-67 to MOG was 1:3, and the mass ratio of the total mass of ZIF-67 and MOG to polyvinyl pyrrolidone was 1:4. The mixed solution was magnetically stirred at 35°C for 16 hours to obtain a uniform spinning solution.

[0077] 50 mL of spinning solution was placed in a 100 mL syringe and electrospun to produce electrospun nanofibers. The electrospinning parameters were: needle voltage of 11 kV, injection rate of 1.5 mL / h, collection speed of 350 rpm, round-trip distance of 100 mm, spinning temperature of 18°C, and spinning humidity of 20% RH. The electrospun nanofibers were then dried in a vacuum oven at 70°C for 8 hours to obtain the nanofibers.

[0078] The nanofibers were placed in a high-temperature tube furnace and carbonized under an inert gas atmosphere of N2 (at a flow rate of 60 mL / min). 3 g of peptone was placed in an ark at the inlet of the tube furnace and heated to 900°C at a heating rate of 5°C / min. Carbonization was then carried out at 900°C for 4 hours. After carbonization, the resulting carbon nanocomposite was ground and subjected to high-energy ball milling to obtain the ZIF-MOG-derived composite nanocarbon fiber catalyst (ZMCF-3).

[0079] Example 4

[0080] Dissolve dimethylimidazole in N,N-dimethylformamide and stir for 25 minutes. Then, add cobalt nitrate hexahydrate to the mixture and stir with magnetic stirring at 30°C for 8 hours. The molar ratio of cobalt nitrate hexahydrate to dimethylimidazole is 1:14, and the molar ratio of dimethylimidazole to N,N-dimethylformamide is 1:64. The mixture is then washed and centrifuged to remove impurities, then dried in a vacuum oven at 100°C for 14 hours. Once cooled to room temperature, ZIF-67 is ground and used for later use.

[0081] Cobalt nitrate hexahydrate, resorcinol, and peptone were dissolved in deionized water and magnetically stirred for 15 minutes to allow the solid to slowly dissolve. Subsequently, formaldehyde was slowly added to the mixed solution and stirred for 1.2 hours. The molar ratio of cobalt nitrate hexahydrate, peptone, and resorcinol was 1:4:35, the molar ratio of resorcinol to deionized water was 1:27, and the molar ratio of resorcinol to formaldehyde was 1:2. Ammonia (AR, mass concentration 26%) was slowly added dropwise to the mixed solution in an 80°C water bath to adjust the solution pH to 9. The solution was stirred for 50 minutes to form an organogel. Finally, the mixture was placed in a vacuum drying oven (vacuum degree 133 Pa) and vacuum dried at 40°C for 7 days. The resulting solid was ground to obtain a metal organic gel (MOG).

[0082] The ground ZIF-67, MOG, and polyvinyl pyrrolidone were added to N,N-dimethylformamide (NDM). The mass ratio of ZIF-67 to MOG was 1:4, and the mass ratio of the total mass of ZIF-67 and MOG to polyvinyl pyrrolidone was 1:5. The mixed solution was magnetically stirred at 40°C for 20 hours to obtain a uniform spinning solution.

[0083] 100 mL of spinning solution was placed in a 150 mL syringe and electrospun to produce electrospun nanofibers. The electrospinning parameters were: needle voltage of 10 kV, injection rate of 1.2 mL / h, collection speed of 300 rpm, round-trip distance of 90 mm, spinning temperature of 16°C, and spinning humidity of 25% RH. The electrospun nanofibers were then dried in a vacuum oven at 50°C for 6 hours to obtain the nanofibers.

[0084] The nanofibers were placed in a high-temperature tube furnace and carbonized under an inert gas atmosphere of N2 (at a flow rate of 80 mL / min). 3 g of chitosan was placed in an ark at the inlet of the tube furnace and heated to 950°C at a heating rate of 6°C / min. Carbonization was then carried out at 950°C for 5 hours. After carbonization, the resulting carbon nanocomposite was ground and subjected to high-energy ball milling to obtain the ZIF-MOG-derived composite nanocarbon fiber catalyst (ZMCF-4).

[0085] Example 5

[0086] Dissolve dimethylimidazole in N,N-dimethylformamide and stir for 30 minutes. Then, add zinc nitrate hexahydrate to the mixture and stir with magnetic stirring at 35°C for 10 hours. The molar ratio of zinc nitrate hexahydrate to dimethylimidazole is 1:16, and the molar ratio of dimethylimidazole to N,N-dimethylformamide is 1:80. The mixture is then washed and centrifuged to remove impurities, then dried in a vacuum oven at 110°C for 16 hours. Once cooled to room temperature, ZIF-67 is ground and used for later use.

[0087] Zinc nitrate hexahydrate, resorcinol, and peptone were dissolved in deionized water and magnetically stirred for 15 minutes to allow the solid to slowly dissolve. Subsequently, formaldehyde was slowly added to the mixed solution and stirred for 1.5 hours. The molar ratio of zinc nitrate hexahydrate, peptone, and resorcinol was 1:5:40, the molar ratio of resorcinol to deionized water was 1:27, and the molar ratio of resorcinol to formaldehyde was 1:2. Ammonia (AR, mass concentration 27%) was slowly added dropwise to the mixed solution in a 90°C water bath to adjust the solution pH to 9.5. The solution was stirred for 60 minutes to form an organogel. Finally, the mixture was placed in a vacuum drying oven (vacuum degree 133 Pa) and vacuum dried at 90°C for 8 days. The resulting solid was ground to obtain a metal organic gel (MOG).

[0088] The ground ZIF-67, MOG, and polyvinyl alcohol were added to N,N-dimethylformamide (NDM). The mass ratio of ZIF-67 to MOG was 4:1, and the mass ratio of the total mass of ZIF-67 and MOG to polyvinyl alcohol was 1:6. The mixed solution was magnetically stirred at 45°C for 28 hours to obtain a uniform spinning solution.

[0089] 200 mL of spinning solution was placed in a 400 mL syringe and electrospun nanofibers were obtained using the following electrospinning parameters: needle voltage of 15 kV, injection rate of 0.8 mL / h, collection speed of 250 rpm, round-trip distance of 80 mm, spinning temperature of 14°C, and spinning humidity of 30% RH. The electrospun nanofibers were then dried in a vacuum drying oven at 40°C for 14 hours to obtain the nanofibers.

[0090] The nanofibers were placed in a high-temperature tube furnace and carbonized under an inert gas atmosphere of N2 (at a flow rate of 100 mL / min). 3 g of chitosan was placed in an ark at the inlet of the tube furnace and heated to 1050°C at a heating rate of 7°C / min. Carbonization was then carried out at 1050°C for 6 h. After carbonization, the resulting carbon nanocomposite was ground and subjected to high-energy ball milling to obtain the ZIF-MOG-derived composite nanocarbon fiber catalyst (ZMCF-5).

[0091] Example 6

[0092] Dissolve dimethylimidazole in N,N-dimethylformamide and stir for 35 minutes. Then, add cobalt nitrate hexahydrate to the mixture and stir with magnetic stirring at 40°C for 12 hours. The molar ratio of cobalt nitrate hexahydrate to dimethylimidazole is 1:18, and the molar ratio of dimethylimidazole to N,N-dimethylformamide is 1:96. The mixture is then washed and centrifuged to remove impurities, then dried in a vacuum oven at 120°C for 18 hours. Once cooled to room temperature, ZIF-67 is ground and used for later use.

[0093] Cobalt nitrate hexahydrate, resorcinol, and peptone were dissolved in deionized water and magnetically stirred for 15 minutes to allow the solid to slowly dissolve. Subsequently, formaldehyde was slowly added to the mixed solution and stirred for 1.8 hours. The molar ratio of cobalt nitrate hexahydrate, peptone, and resorcinol was 1:6:45, the molar ratio of resorcinol to deionized water was 1:27, and the molar ratio of resorcinol to formaldehyde was 1:2. Ammonia water (AR, mass concentration 26%) was slowly added dropwise to the mixed solution in a 100°C water bath. The solution pH was adjusted to 10, and the reaction was stirred for 70 minutes to form an organogel. Finally, the mixture was placed in a vacuum drying oven (vacuum degree 133 Pa) and vacuum dried at 100°C for 9 days. The resulting solid was ground to obtain a metal organic gel (MOG).

[0094] The ground ZIF-67, MOG, and polyvinyl alcohol were added to N,N-dimethylformamide (NDM). The mass ratio of ZIF-67 to MOG was 2:1, and the mass ratio of the total mass of ZIF-67 and MOG to polyvinyl alcohol was 1:7. The mixed solution was magnetically stirred at 50°C for 32 hours to obtain a uniform spinning solution.

[0095] 250 mL of spinning solution was placed in a 300 mL syringe and electrospun to produce electrospun nanofibers. The electrospinning parameters were: needle voltage of 16 kV, injection rate of 0.5 mL / h, collection speed of 200 rpm, round-trip distance of 70 mm, spinning temperature of 12°C, and spinning humidity of 35% RH. The electrospun nanofibers were then dried in a vacuum oven at 90°C for 16 hours to obtain the nanofibers.

[0096] The nanofibers were carbonized in a high-temperature tube furnace under an inert N2 atmosphere (N2 flow rate of 120 mL / min). 3 g of urea was placed in an ark at the inlet of the tube furnace and heated to 1000°C at a heating rate of 8°C / min. Carbonization was then performed at 1000°C for 7 hours. After carbonization, the resulting carbon nanocomposite was ground and subjected to high-energy ball milling to obtain the ZIF-MOG-derived composite nanocarbon fiber catalyst (ZMCF-6).

[0097] Example 7

[0098] Dissolve dimethylimidazole in N,N-dimethylformamide and stir for 40 minutes. Then, add cobalt nitrate hexahydrate to the mixture and stir with magnetic stirring at 45°C for 14 hours. The molar ratio of cobalt nitrate hexahydrate to dimethylimidazole is 1:20, and the molar ratio of dimethylimidazole to N,N-dimethylformamide is 1:112. The mixture is then washed and centrifuged to remove impurities, then dried in a vacuum oven at 130°C for 20 hours. Once cooled to room temperature, ZIF-67 is ground and used for later use.

[0099] Cobalt nitrate hexahydrate, resorcinol, and peptone were dissolved in deionized water and magnetically stirred for 15 minutes to allow the solid to slowly dissolve. Subsequently, formaldehyde was slowly added to the mixed solution and stirred for 2 hours. The molar ratio of cobalt nitrate hexahydrate, peptone, and resorcinol was 1:7:50, the molar ratio of resorcinol to deionized water was 1:27, and the molar ratio of resorcinol to formaldehyde was 1:2. Ammonia (AR, mass concentration 26%) was slowly added dropwise to the mixed solution in a 110°C water bath to adjust the solution pH to 10.5. The solution was stirred for 80 minutes to form an organogel. Finally, the mixture was placed in a vacuum drying oven (vacuum degree 133 Pa) and vacuum dried at 110°C for 10 days. The resulting solid was ground to obtain a metal organic gel (MOG).

[0100] The ground ZIF-67, MOG, and polystyrene were added to N,N-dimethylformamide (NDM). The mass ratio of ZIF-67 to MOG was 1:8, and the mass ratio of the total mass of ZIF-67 and MOG to polystyrene was 1:8. The mixed solution was magnetically stirred at 55°C for 36 hours to obtain a uniform spinning solution.

[0101] 300 mL of spinning solution was placed in a 400 mL syringe and electrospun to produce electrospun nanofibers. The electrospinning parameters were: needle voltage of 17 kV, injection rate of 0.9 mL / h, collection speed of 500 rpm, round-trip distance of 60 mm, spinning temperature of 26°C, and spinning humidity of 40% RH. The electrospun nanofibers were then dried in a vacuum oven at 95°C for 18 hours to obtain the nanofibers.

[0102] The nanofibers were carbonized in a high-temperature tube furnace under an inert N2 atmosphere (N2 flow rate of 140 mL / min). 3 g of chitosan was placed in an ark at the inlet of the tube furnace and heated to 1100°C at a heating rate of 9°C / min. Carbonization was then performed at 1100°C for 8 hours. After carbonization, the resulting carbon nanocomposite was ground and subjected to high-energy ball milling to obtain the ZIF-MOG-derived composite nanocarbon fiber catalyst (ZMCF-7).

[0103] Example 8

[0104] Dissolve dimethylimidazole in N,N-dimethylformamide and stir for 44 minutes. Then, add cobalt nitrate hexahydrate to the mixture and stir with magnetic stirring at 50°C for 16 hours. The molar ratio of cobalt nitrate hexahydrate to dimethylimidazole is 1:22, and the molar ratio of dimethylimidazole to N,N-dimethylformamide is 1:128. The mixture is then washed and centrifuged to remove impurities, then dried in a vacuum oven at 140°C for 22 hours. Once cooled to room temperature, ZIF-67 is ground and used for later use.

[0105] Cobalt nitrate hexahydrate, resorcinol, and peptone were dissolved in deionized water and magnetically stirred for 15 minutes to allow the solid to slowly dissolve. Subsequently, formaldehyde was slowly added to the mixed solution and stirred for 2.2 hours. The molar ratio of cobalt nitrate hexahydrate, peptone, and resorcinol was 1:8:55, the molar ratio of resorcinol to deionized water was 1:27, and the molar ratio of resorcinol to formaldehyde was 1:2. Ammonia water (AR, mass concentration 26%) was slowly added dropwise to the mixed solution in a 120°C water bath to adjust the solution pH to 12. The solution was stirred for 90 minutes to form an organogel. Finally, the mixture was placed in a vacuum drying oven (vacuum degree 133 Pa) and vacuum dried at 120°C for 3 days. The resulting solid was ground to obtain a metal organic gel (MOG).

[0106] The ground ZIF-67, MOG, and polystyrene were added to N,N-dimethylformamide (NDM). The mass ratio of ZIF-67 to MOG was 8:1, and the mass ratio of the combined mass of ZIF-67 and MOG to polystyrene was 1:9. The mixed solution was magnetically stirred at 60°C for 40 hours to obtain a uniform spinning solution.

[0107] 600 mL of spinning solution was placed in a 700 mL syringe and electrospun to produce electrospun nanofibers. The electrospinning parameters were: needle voltage of 18 kV, injection rate of 0.7 mL / h, collection speed of 550 rpm, round-trip distance of 130 mm, spinning temperature of 28°C, and spinning humidity of 45% RH. The electrospun nanofibers were then dried in a vacuum oven at 100°C for 20 hours to obtain the nanofibers.

[0108] The nanofibers were placed in a high-temperature tube furnace and carbonized under an inert gas atmosphere of N2 (at a flow rate of 160 mL / min). 3 g of peptone was placed in an ark at the inlet of the tube furnace and heated to 700°C at a heating rate of 10°C / min. Carbonization was then carried out at 700°C for 9 hours. After carbonization, the resulting carbon nanocomposite was ground and subjected to high-energy ball milling to obtain the ZIF-MOG-derived composite nanocarbon fiber catalyst (ZMCF-8).

[0109] Example 9

[0110] Dissolve dimethylimidazole in N,N-dimethylformamide and stir for 46 minutes. Then, add cobalt nitrate hexahydrate to the mixture and stir with magnetic stirring at 55°C for 17 hours. The molar ratio of cobalt nitrate hexahydrate to dimethylimidazole is 1:24, and the molar ratio of dimethylimidazole to N,N-dimethylformamide is 1:144. The mixture is then washed and centrifuged to remove impurities, then dried in a vacuum oven at 150°C for 24 hours. Once cooled to room temperature, ZIF-67 is ground and used for later use.

[0111] Cobalt nitrate hexahydrate, resorcinol, and peptone were dissolved in deionized water and magnetically stirred for 15 minutes to allow the solid to slowly dissolve. Subsequently, formaldehyde was slowly added to the mixed solution and stirred for 2.5 hours. The molar ratio of cobalt nitrate hexahydrate, peptone, and resorcinol was 1:9:60, the molar ratio of resorcinol to deionized water was 1:27, and the molar ratio of resorcinol to formaldehyde was 1:2. Ammonia (AR, mass concentration 26%) was slowly added dropwise to the mixed solution in a 130°C water bath to adjust the solution pH to 13. The reaction was stirred for 100 minutes to form an organogel. Finally, the mixture was placed in a vacuum drying oven (vacuum degree 133 Pa) and vacuum dried at 130°C for 2 days. The resulting solid was ground to obtain a metal organic gel (MOG).

[0112] The ground ZIF-67, MOG, and polymethyl methacrylate were added to N,N-dimethylformamide (NDM). The mass ratio of ZIF-67 to MOG was 10:1, and the mass ratio of the total mass of ZIF-67 and MOG to polymethyl methacrylate was 2:1. The mixed solution was magnetically stirred at 65°C for 42 hours to obtain a uniform spinning solution.

[0113] 700 mL of spinning solution was placed in an 800 mL syringe and electrospun to produce electrospun nanofibers. The electrospinning parameters were: needle voltage of 19 kV, injection rate of 1.8 mL / h, collection speed of 600 rpm, round-trip distance of 140 mm, spinning temperature of 30°C, and spinning humidity of 50% RH. The electrospun nanofibers were then dried in a vacuum oven at 85°C for 22 hours to obtain the nanofibers.

[0114] The nanofibers were carbonized in a high-temperature tube furnace under an inert N2 atmosphere (N2 flow rate of 180 mL / min). 3 g of peptone was placed in an ark at the inlet of the tube furnace. The temperature was raised to 650°C at a heating rate of 12°C / min and carbonized at 650°C for 11 hours. After carbonization, the resulting carbon nanocomposite was ground and subjected to high-energy ball milling to obtain the ZIF-MOG-derived composite nanocarbon fiber catalyst (ZMCF-9).

[0115] Example 10

[0116] Dissolve dimethylimidazole in N,N-dimethylformamide and stir for 50 minutes. Then, add cobalt nitrate hexahydrate to the mixture and stir with magnetic stirring at 80°C for 48 hours. The molar ratio of cobalt nitrate hexahydrate to dimethylimidazole is 1:80, and the molar ratio of dimethylimidazole to N,N-dimethylformamide is 1:160. The mixture is then washed and centrifuged to remove impurities, then dried in a vacuum oven at 200°C for 72 hours. Once cooled to room temperature, ZIF-67 is ground and used for later use.

[0117] Cobalt nitrate hexahydrate, resorcinol, and peptone were dissolved in deionized water and magnetically stirred for 15 minutes to allow the solid to slowly dissolve. Subsequently, formaldehyde was slowly added to the mixed solution and stirred for 4 hours. The molar ratio of cobalt nitrate hexahydrate, peptone, and resorcinol was 1:10:200, the molar ratio of resorcinol to deionized water was 1:27, and the molar ratio of resorcinol to formaldehyde was 1:2. Ammonia (AR, mass concentration 26%) was slowly added dropwise to the mixed solution in an 80°C water bath to adjust the solution pH to 14. The solution was stirred for 120 minutes to form an organogel. Finally, the mixture was placed in a vacuum drying oven (vacuum degree 133 Pa) and vacuum dried at 105°C for 10 days. The resulting solid was ground to obtain a metal organic gel (MOG).

[0118] The ground ZIF-67, MOG, and polymethyl methacrylate were added to N,N-dimethylformamide (NDM). The mass ratio of ZIF-67 to MOG was 100:1, and the mass ratio of the combined mass of ZIF-67 and MOG to polymethyl methacrylate was 10:1. The mixed solution was magnetically stirred at 100°C for 96 hours to obtain a uniform spinning solution.

[0119] 800 mL of spinning solution was placed in a 1000 mL syringe and electrospun to produce electrospun nanofibers. The electrospinning parameters were: needle voltage of 50 kV, injection rate of 10 mL / h, collection speed of 1000 rpm, round-trip distance of 180 mm, spinning temperature of 50°C, and spinning humidity of 60% RH. The electrospun nanofibers were then dried in a vacuum oven at 100°C for 48 hours to obtain the nanofibers.

[0120] The nanofibers were placed in a high-temperature tube furnace and carbonized under an inert gas atmosphere of N2 (at a flow rate of 200 mL / min). 3 g of urea was placed in an ark at the inlet of the tube furnace and heated to 1200°C at a heating rate of 15°C / min. Carbonization was then carried out at 1200°C for 12 hours. After carbonization, the resulting carbon nanocomposite was ground and subjected to high-energy ball milling to obtain the ZIF-MOG-derived composite nanocarbon fiber catalyst (ZMCF-10).

[0121] Comparative Example 1

[0122] The preparation of MOG in Example 1 was omitted, and other processes were the same as in Example 1. ZIF-67 was directly subjected to electrospinning and high-temperature treatment to obtain nanocarbon fiber material ZCF.

[0123] The performance tests were carried out on ZMCF-1 of Example 1, ZMCF-2 of Example 2 and ZCF of Comparative Example 1: the carbon fiber material itself was subjected to AC impedance method, linear sweep voltammetry and other tests using an electrochemical workstation to determine the catalytic activity of the catalyst itself; the carbon fiber materials of Examples 1 to 2 and Comparative Example 1 were assembled into batteries, and the charge-discharge cycle and power density tests were carried out. The specific process for preparing the battery is as follows: the zinc-air battery uses a polished zinc plate as the anode, an air electrode as the cathode, and a 6MKOH solution as the electrolyte. The ratio of the ink-colored catalyst slurry is: 5mg catalyst + 50μL Nafion + 950μL anhydrous ethanol. Take 200μL of the ink-colored catalyst slurry and drop it on the nickel mesh gas diffusion layer to form a catalytic layer (effective geometric area is 1cm 2 , the catalyst loading was 1 mg·cm -2 Next, place the zinc sheet on the anode plate, followed by the anti-dendrite diaphragm, sealing ring, liquid storage plate, sealing ring, air cathode, and cathode plate. Finally, install the screws, washers, and nuts, tightening them symmetrically to ensure uniform force. Finally, connect the assembled battery to the liquid storage bottle and the circulating peristaltic pump. Constant current charge and discharge tests are performed on the assembled battery using the Blue Electric Battery Testing System.

[0124] The ORR and LSV polarization curves of ZMCF-1 of Example 1, ZIF-67 of Comparative Example 1, and Pt / C in 0.1 mol / L KOH solution are shown in FIG. Figure 1 As shown; the OER polarization curves of ZMCF-1 of Example 1, ZIF-67 of Comparative Example 1, and RuO2 in 1 mol / L KOH solution are shown as follows: Figure 2 As shown; the discharge polarization curve and power density of the zinc-air battery assembled with ZMCF-1 and Pt / C as cathode catalysts in Example 1 are shown in FIG. Figure 3 As shown; the zinc-air battery and Pt / C-RuO2 battery assembled with ZMCF-1 of Example 1 as cathode catalyst at 10mA / cm 2 The constant current charge and discharge curve under Figure 4 The ORR and LSV polarization curves of ZMCF-2 and Pt / C in 0.1 mol / L KOH solution of Example 2 are shown in FIG. Figure 5 As shown; The OER polarization curves of ZMCF-2 and RuO2 in 1 mol / L KOH solution of Example 2 are shown as Figure 6 shown.

[0125] like Figure 1 As shown, the half-wave potential (E 1 / 2 ) reaches 0.8 V (vs. RHE), which is almost equivalent to the half-wave potential (E 1 / 2 =0.82V), showing excellent ORR catalytic activity. Figure 2 It can be seen that at 10mA / cm 2 At the current density, the corresponding OER overpotential of ZMCF-1 is 396 mV, lower than that of Z-CNF (430 mV), but still 41 mV lower than that of RuO2 (355 mV). With increasing current density, the overpotential of ZMCF-1 gradually approaches or even falls below that of RuO2, indicating that ZMCF-1 has good OER catalytic activity. Figure 3 It can be seen that the maximum power density of the zinc-air battery assembled with ZMCF-1 material can reach 115.7mW / cm 2 , slightly lower than the maximum power density of Pt / C-RuO2 battery 121mW / cm 2 , showing excellent battery performance. Figure 4 For batteries at 10mA / cm 2The constant current charge and discharge curves below show that the initial charge and discharge voltage range of the ZMCF battery is 1.3V, but after running for 200h, its charge and discharge voltage range gradually decreases and remains stable (about 1.18V). Under the same conditions, the Pt / C-RuO2 battery only ran for 85h, at which time the charge and discharge voltage range increased to 1.62V. This shows that the zinc-air battery assembled with ZMCF-1 material has excellent cycle stability. Figure 5 It can be seen that the half-wave potential (E 1 / 2 ) reaches 0.78 V (vs. RHE), which is close to the half-wave potential (E 1 / 2 =0.82V), showing excellent ORR catalytic activity. Figure 6 It can be seen that at 10mA / cm 2 At the current density, the OER overpotential of ZMCF-2 material is 400mV, which is 45mV lower than the overpotential of RuO2 (355mV). However, as the current density increases, the overpotential of ZMCF-2 material gradually approaches and then falls below the overpotential of RuO2, indicating that ZMCF-2 material exhibits good OER catalytic activity.

[0126] The results of the examples show that the ZIF-MOG-derived composite carbon fiber (ZMCF) material prepared by the present invention accelerates the kinetic process of oxygen reduction (ORR) and reduces the overpotential of the oxygen evolution (OER) reaction. After long-term charge and discharge cycles, the voltage range remains stable without obvious attenuation, and has broad development prospects.

[0127] The present invention combines a zeolitic imidazole framework (ZIF-67) with a metal organic gel (MOG) and utilizes electrospinning technology to achieve a microscopic composite of the two at the nanoscale, forming a nanofiber network structure. This enhances the conductivity of the material while also exposing more active sites. High-temperature carbonization, heteroatom doping, and high-energy ball milling further enhance the material's conductivity and catalytic activity, building on the advantages of co-doping with a one-dimensional ZIF gel, increasing active sites, and improving the conductivity and electrochemical activity of the nanofibers. This invention is of great significance for preparing a new, high-performance, non-precious metal bifunctional catalyst, improving the catalyst's conductivity and high electrocatalytic activity, further enhancing the power density and charge-discharge efficiency of zinc-air batteries, and thus promoting the industrialization of zinc-air batteries.

[0128] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the present invention. These improvements and modifications should also be regarded as within the scope of protection of the present invention.

Claims

1. A method for preparing a ZIF-MOG derived composite nanocarbon fiber catalyst, characterized in that: The following steps are included: 1) Dimethylimidazole, a metal salt, and an organic solvent are mixed and reacted to obtain ZIF-67; 2) mixing the metal salt, nitrogen-containing component, resorcinol and water to obtain a mixed solution, and sequentially adding formaldehyde and ammonia water to the mixed solution to react and form a metal organic gel; 3) mixing ZIF-67, metal organic gel, nanofiber polymer and solvent to obtain a spinning solution; 4) The spinning solution is electrospun and dried sequentially to obtain nanofibers; 5) The nanofibers are sequentially subjected to high-temperature carbonization and refinement treatment to obtain a ZIF-MOG-derived composite nanocarbon fiber catalyst; In step 1), the molar ratio of the metal salt to dimethylimidazole is 1:8-80, and the metal salt is a cobalt salt.

2. The preparation method according to claim 1, characterized in that Step 1) The organic solvent is ethanol, N,N-dimethylformamide or methanol; the molar ratio of dimethylimidazole to the organic solvent is 1:16-160; The reaction temperature is 15-80° C., and the reaction time is 2-48 hours.

3. The preparation method according to claim 1 or 2, characterized in that Step 2) the metal salt is an iron salt, a cobalt salt, a nickel salt, a copper salt or a zinc salt; the nitrogen-containing component is peptone, melamine, urea or chitosan; The reaction time is 5-120 minutes, the reaction temperature is 30-140° C., and ammonia water is added to adjust the pH value of the system to 7-14.

4. The preparation method according to claim 3, characterized in that Step 2) The molar ratio of the metal salt, the nitrogen-containing component and resorcinol is 1:1-10:20-200, the molar ratio of resorcinol to formaldehyde is 1:1-3, and the molar ratio of resorcinol to water is 1:25-30.

5. The preparation method according to claim 1, characterized in that Step 3) the nanofiber polymer comprises polyacrylonitrile, polyvinyl pyrrolidone, polyvinyl alcohol, polystyrene or polymethyl methacrylate; the molecular weight of polyacrylonitrile is 50,000-300,000, and the solvent comprises water, N,N-dimethylformamide, methanol or ethanol; The mixing temperature is 20-100° C., and the mixing time is 6-96 hours.

6. The preparation method according to claim 4 or 5, characterized in that In step 3), the mass ratio of the ZIF-67 to the metal organic gel is 1-100:1-100, and the mass ratio of the total mass of the ZIF-67 and the metal organic gel to the nanofiber polymer is 1-10:1-10.

7. The preparation method according to claim 6, characterized in that Step 4) The electrospinning process parameters are as follows: needle voltage of 5-50 kV, injection rate of 0.1-10 mL / h, collection speed of 200-1000 rpm, round trip distance of 60-180 mm, spinning temperature of 10-50° C., spinning humidity of 10-60% RH; drying temperature of 40-100° C., and drying time of 2-48 h.

8. The preparation method according to claim 1 or 7, characterized in that Step 5) The high-temperature carbonization temperature is 650-1200° C., the high-temperature carbonization time is 1-12 hours, and the heating rate of the high-temperature carbonization is 2-15° C. / min. The high-temperature carbonization is carried out under a protective gas atmosphere with a flow rate of the protective gas of 10-200 mL / min.

9. The ZIF-MOG derived composite nanocarbon fiber catalyst prepared by the preparation method according to any one of claims 1 to 8.

10. Use of the ZIF-MOG derived composite nanocarbon fiber catalyst in a battery according to claim 9, characterized in that: The battery is a battery in which oxygen participates in the cathode reaction.

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