A nano-enhanced biomass hydrogen production membrane electrode integrated device and a preparation method thereof

Abstract

The application relates to the technical field of hydrogen production equipment, in particular to a nano-enhanced biomass hydrogen production membrane electrode integrated device and a preparation method thereof. The device comprises a tank body, two membrane electrode assemblies are arranged in the tank body and are fixed through bolts, a shell is arranged on one side of the membrane electrode assembly through bolts, an exhaust hole is arranged on one side of the shell, a reaction zone is arranged between the two membrane electrode assemblies, and a hydrogen zone is arranged between one shell and one side of the inner wall of the tank body. The proton exchange membrane, the honeycomb tube frame and the diffusion membrane are integrated in the U-shaped frame, the catalysis, mass transfer and separation functions are highly coordinated, the biomass conversion efficiency in the reaction zone is greatly improved, the porous spraying pipe is matched with the material injection port, the biomass slurry can be uniformly distributed, local overheating or uneven reaction substance concentration can be avoided, the hydrogen production rate stability is improved, the hydrogen zone and the oxygen zone are physically isolated through the filter membrane, the exhaust pipe is combined to directionally guide the gas, cross contamination can be avoided, and the hydrogen recovery rate is improved.

Description

Technical Field

[0001] This invention relates to the field of hydrogen production equipment technology, specifically to a nano-enhanced biomass hydrogen production membrane electrode integrated device and its preparation method. Background Technology

[0002] Membrane electrode assembly (MEA) for hydrogen production is a method that utilizes proton exchange membrane (PEM) water electrolysis technology to produce hydrogen. MEAs play a crucial role in PEM water electrolysis for hydrogen production and in the manufacture of PEM fuel cells. They not only serve as microchannels for multiphase mass transfer but also provide a site for electrochemical reactions. The structure of a MEA includes a proton exchange membrane, an anode, and a cathode, with the proton exchange membrane located at the center, forming an electrochemical reaction system with the anode and cathode on either side. With technological advancements, nano-enhanced biomass hydrogen production MEAs have emerged. These nano-enhanced biomass hydrogen production MEAs are developed by introducing nanomaterials to optimize the structure and performance of the MEA, primarily for improving the efficiency and stability of biomass hydrogen production reactions.

[0003] For example, patent application CN202310216316.3, published on 20230711, discloses a PEM water electrolysis hydrogen production membrane electrode and its preparation method, relating to the field of water electrolysis hydrogen production technology. The PEM water electrolysis hydrogen production membrane electrode includes a proton exchange membrane and cathode and anode catalyst layers located on both sides of the proton exchange membrane. Both the cathode and anode catalyst layers include a catalyst, a perfluorosulfonic acid ionomer, a solvent, and a perfluorosulfonic acid ionomer dispersion promoter; the perfluorosulfonic acid ionomer dispersion promoter is at least one selected from dimethyl sulfoxide, tetrahydrofuran, and N-methylpyrrolidone. The PEM hydrogen production membrane electrode catalyst layer prepared by this invention, due to the addition of the ionomer dispersion promoter, increases the dispersion of the ionomer in the catalyst layer, thereby constructing a catalyst layer with a good catalyst / ionomer microporous structure, reducing the obstruction to gas and water transport, and improving the membrane electrode performance. The preparation method used in this invention requires no special processing technology or equipment, is simple and quick to operate, and is easy to achieve mass production.

[0004] The above-mentioned and existing membrane electrode hydrogen production technologies generally suffer from the following problems:

[0005] (1) Low hydrogen purity: Impurity gases such as CO and H2S generated during the reaction are difficult to separate effectively, resulting in insufficient hydrogen purity (usually <95%), which cannot meet the high requirements of fuel cells and other scenarios.

[0006] (2) Catalyst is easily deactivated: Ash, heavy metals and other impurities in biomass raw materials can easily lead to catalyst poisoning and short service life (<2000 hours).

[0007] (3) Complex system: The pretreatment, reaction and separation modules are set up independently, and the equipment is large in size and has high energy consumption;

[0008] In view of this, there is an urgent need to design a nano-enhanced biomass hydrogen production membrane electrode integrated device and preparation method to solve the above problems. Summary of the Invention

[0009] The purpose of this invention is to provide a nano-enhanced biomass hydrogen production membrane electrode integrated device and preparation method to overcome the above-mentioned shortcomings in the prior art.

[0010] To achieve the above objectives, the present invention provides the following technical solution:

[0011] A nano-enhanced biomass hydrogen production membrane electrode integrated device includes a tank. Two membrane electrode assemblies are bolted to the inside of the tank. A shell is bolted to one side of the outer wall of the membrane electrode assembly. An exhaust hole is opened on one side of the outer wall of the shell. The reaction zone is between the two membrane electrode assemblies. One shell is located between one side of the inner wall of the tank and the hydrogen zone. The other shell is located between the other side of the inner wall of the tank and the oxygen zone. Exhaust pipes are inserted into both sides of the outer wall of the tank. One end of each exhaust pipe extends into the hydrogen zone and the oxygen zone, respectively.

[0012] The membrane electrode assembly includes a U-shaped frame, inside which a proton exchange membrane, a honeycomb tube frame, and a diffusion membrane are respectively installed by bolts, and the honeycomb tube frame is located between the proton exchange membrane and the diffusion membrane;

[0013] The membrane electrode assembly also includes a shell component. Multiple porous spray pipes are threadedly connected to the outer wall of one side of the bottom of the shell component, and the porous spray pipes are inserted into the honeycomb tube frame. An injection port is opened on the outer wall of one side of the top of the shell component, and a piston head is threadedly connected inside the injection port.

[0014] Furthermore, an installation groove is provided on one side of the outer wall of the tank, and an anode connector and a cathode connector are respectively installed on one side of the inner wall of the installation groove by bolts. The anode connector and the cathode connector are electrically connected to the honeycomb tube frame in the two membrane electrode assemblies.

[0015] Furthermore, a drain pump is bolted to one side of the inner wall of the mounting groove, and the drain pump is connected to the housing through a pipe. A return pipe is inserted at the center of one side of the inner wall of the mounting groove, and the other end of the return pipe is installed at the outlet of the drain pump.

[0016] Furthermore, filter membranes are bolted to the interior of the oxygen and hydrogen zones, with one side of the filter membrane in contact with the housing.

[0017] Furthermore, a can cover is bolted to both sides of the top outer wall of the tank, and a can cover is bolted to one side of the top outer wall of the tank, with the can cover located between the two can covers.

[0018] A method for preparing a nano-enhanced biomass hydrogen production membrane electrode includes the following steps:

[0019] Step S1. Catalyst preparation: Fe3O4@CNTS was synthesized by solvothermal method, and Pt nanoparticles were prepared by chemical reduction method;

[0020] Step S2. Anode preparation:

[0021] Step S2.1. Raw material acquisition and processing: Collect biomass materials such as straw and rice husks, and then carry out crushing-washing-washing steps to obtain neutral biomass materials;

[0022] Step S2.2. Carbonization and pulverization: Place the obtained neutral biomass material into a tube furnace, start the tube furnace for carbonization treatment, and after carbonization is completed, take out the carbonized material and put it into a ball mill for pulverization treatment.

[0023] Step S2.3. Impregnation and molding: Prepare catalyst slurry, put the crushed carbonized material into the catalyst slurry for impregnation, after impregnation, take out the carbonized material and mix it with the binder, after mixing, put it into the mold for molding, after completion, take out the workpiece and use machining equipment for finishing treatment;

[0024] Step S2.4. Etching and Synthesis: The nanocomposite catalyst slurry is sprayed onto a porous titanium substrate, annealed to form a gradient pore structure, and then an anode is obtained. Subsequently, interlaced trenches are etched on the surface of the anode catalyst layer using a laser.

[0025] Step S3. Preparation of diffusion film: Select titanium fibers and bond them together with adhesive. After bonding, place them in a mold and cold press them into shape. After forming, place them in a sintering device for sintering. After sintering, obtain the diffusion film.

[0026] Step S4. Preparation of proton exchange membrane: Sulfonated polyether ether ketone is doped with 5-10 wt% nano-TiO2, cast into a film, and then hot-pressed to cure, forming a proton exchange membrane;

[0027] Step S5. Cathode preparation: Pt nanoparticles are anchored to nitrogen-doped carbon fibers using electrospinning technology, followed by heat treatment to obtain the cathode; Step S6. Membrane electrode assembly: The obtained cathode and anode are combined with the prepared diffusion membrane and proton exchange membrane, arranged from the outside to the inside as proton exchange membrane, cathode / anode, and diffusion membrane, and then combined together by hot pressing molding process.

[0028] Furthermore, in the catalyst preparation process of step S1, the preparation method of Fe3O4@CNTS is as follows:

[0029] S1-1. Raw material proportioning and pretreatment

[0030] S1-1.1. Carbon and nitrogen precursor: Dicyandiamine (C2H4N4) and glucose (C6H4N4) are reacted... 12 O6 was mixed at a mass ratio of 1:1 to 1:3 as a carbon and nitrogen source, and then ground and mixed in a ball mill at 300 rpm for 2 hours.

[0031] S1-1.2. Introduction of metal salts: During ball milling, ferric nitrate (Fe(NO3)3∙9H2O) and nickel nitrate (Ni(NO3)2∙6H2O) are added to the inside of the ball mill, and the total mass ratio of metal salts to carbon and nitrogen precursors is 1:5-1:10;

[0032] S1-2. High-temperature calcination process

[0033] S1-2.1. Inert atmosphere carbonization: The mixed powder is placed in a tube furnace and heated to 800-1000℃ at 5℃ / min under a nitrogen atmosphere, and held for 2-4 hours. During this process, glucose is carbonized to form a porous carbon framework, and dicyandiamine decomposes to produce NH3 and HCN, which promotes nitrogen doping.

[0034] S1-2.2. Core-shell structure formation:

[0035] Fe 2+ and Ni 2+ During the carbonization process, it is reduced to FeNi alloy nanoparticles (core) and coated with a nitrogen-doped carbon layer (shell) to form a Fe3O4@CNTS structure. The thickness of the carbon shell is controlled by regulating the heating rate and carbonization time.

[0036] S1-3. Post-processing optimization

[0037] S1-3.1. Acid washing and purification: The calcined product was immersed in 0.5M H2SO4 and ultrasonically treated for 6 hours to remove uncoated metal particles and impurities; then acid washed and washed with water until neutral, and vacuum dried at 80℃ for 12 hours.

[0038] S1-3.2. Graphene composite: Fe3O4@CNTS and graphene oxide are mixed at a mass ratio of 1:2, and then fed into a calcination furnace and calcined for 1 hour at 800℃ to form a graphene support structure.

[0039] Furthermore, The preparation method of nanoparticles is as follows:

[0040] Step S2-1. Heat the hexachloroplatinic acid (H2PtCl6) solution to boiling, and then quickly inject the reducing agent solution (a mixture of NaBH4 and citric acid).

[0041] Step S2-2. After reacting for 10 minutes, cool the mixture. After cooling, pour the mixture into a centrifuge, start the centrifuge, and centrifuge to obtain Pt nanoparticles (particle size <10 nm).

[0042] In step S2.1, during raw material acquisition and processing, rice husks and straw biomass need to be crushed to 100-200 mesh, and 10% HNO3 solution is used for washing.

[0043] In step S2.2. carbonization and pulverization, carbonization is carried out in an argon atmosphere at a temperature of 800℃ for 2 hours. After carbonization, a porous carbon support with a specific surface area >1200m² / g is obtained.

[0044] In step S2.3, during impregnation and molding, an adhesive containing metal powder is selected as the adhesive;

[0045] In step S2.4, etching and synthesis, the etched trenches have a width of 150 μm, a depth of 50 μm, and a spacing of 300 μm, and the channel density reaches 15 cm / cm².

[0046] Furthermore, the specific method for preparing the diffusion film in step S3 is as follows:

[0047] Step S3-1. Raw material preparation: Select high-purity titanium fiber, and pickle the high-purity titanium fiber with 5% HNO3 solution, and then use polyvinyl alcohol to bond the high-purity titanium fiber.

[0048] Step S3-2. Fiber layup and pre-compression molding: Titanium fibers are evenly laid in the mold with an initial layup thickness of about 1.2-1.5 mm. The fibers are then vibrated and screened to ensure uniform distribution. The fibers are then cold-compressed under a pressure of 200-300 MPa to form a preliminary porous structure with a thickness of about 0.8-1.0 mm after pre-compression.

[0049] Step S3-3. Vacuum sintering: Place the pre-pressed billet in a vacuum sintering furnace, with a heating rate of 5-10℃ / min, a target temperature of 1200-1350℃, and a holding time of 2-4 hours. Argon or high-purity nitrogen is introduced throughout the process to protect against oxidation.

[0050] Step S3-4. Post-treatment and finishing: The surface of the sintered green body is treated by pickling and passivation, water washing and drying techniques;

[0051] Furthermore, the specific method for preparing the proton exchange membrane in step S4 is as follows:

[0052] Step S4-1. Nanomaterial selection: Select silica, layered double hydroxide or carbon-based nanomaterials as dopants, control the particle size to 20-100nm, and acidify the hydrophobic nanomaterials such as carbon-based nanomaterials. After acidification, add the nanomaterials to DMSO solvent at a ratio of 5-10wt% and sonicate for 1-2 hours.

[0053] Step S4-2. SPEEK solution preparation and blending: Dissolve polyether ether ketone (PEEK) in 98% concentrated sulfuric acid, control the sulfonation temperature at 60-80℃ and the reaction time at 4-6 hours, adjust the degree of sulfonation (DS) to 60-70%, then separate the product by ice-water precipitation, wash until neutral and vacuum dry, then dissolve SPEEK in DMSO solution (concentration 8-12wt%), add the pretreated nano-dispersion, heat to 60℃ and mechanically stir for 4 hours to form a homogeneous mixed solution;

[0054] Step S4-3. Casting and Hot-Pressure Curing: The mixed solution is cast onto a clean glass substrate. A doctor blade is used to control the wet film thickness to 0.3-0.5 mm. The solvent is allowed to evaporate at room temperature for 12 hours. Then, the film is transferred to a vacuum drying oven (60℃, 6 hours) to completely remove residual solvent. The nascent film is then placed in a hot press at a temperature of 120-140℃ and a pressure of 5-10 MPa for 30-60 minutes to promote the interfacial bonding between the nanomaterials and SPEEK. After cooling, the film is peeled off to obtain a final film thickness of 50-100 μm.

[0055] Furthermore, the specific method for cathode preparation in step S5 is as follows:

[0056] Step S5-1. Preparation of precursor spinning solution: Dissolve nitrogen-containing precursor and Pt precursor in organic solvent to form a uniform spinning solution. Then, add nitrogen-containing compound to provide abundant nitrogen sites for carbon fiber and enhance Pt anchoring ability.

[0057] Step S5-2. Electrospinning to prepare fiber precursor: Pour the fiber solution into the electrospinning machine, start the electrospinning machine, set the voltage to 12-20kV, the feed speed to 0.5-2mL / h, and the spinning distance to 10-16cm to form continuous nanofibers with a diameter of 100-500nm. Then, use a polytetrafluoroethylene film to prevent fiber adhesion. Step S5-3. Heat treatment and carbonization: Heat at 180-250℃ in air for 1-4h to stabilize the fiber morphology and promote the formation of nitrogen-containing functional groups. Then, calcine at 700-1000℃ in an inert atmosphere for 1-4h to convert the polymer into nitrogen-doped carbon fibers (N-CNFs). At the same time, reduce the Pt precursor in situ to Pt nanoparticles (particle size <5nm).

[0058] Step S5-4. Pt nanoparticle anchoring optimization: Through the strong interaction between C and N atoms and Pt during carbonization, Pt particles are uniformly dispersed on the fiber surface and internal pores. Impurities are removed by hydrogen reduction or acid washing to further expose Pt active sites and enhance electrochemical activity.

[0059] In the above technical solution, the present invention provides a nano-enhanced biomass hydrogen production membrane electrode integrated device and preparation method, which has the following advantages: (1) The present invention integrates the proton exchange membrane, honeycomb tube frame and diffusion membrane into the U-shaped frame to achieve a high degree of synergy of catalysis, mass transfer and separation functions, which greatly improves the biomass conversion efficiency in the reaction zone. In addition, the porous spray pipe and the injection port can achieve uniform distribution of biomass slurry, avoid local overheating or uneven concentration of reactants, and improve the stability of hydrogen production rate. At the same time, the hydrogen zone and oxygen zone are physically isolated by the filter membrane, and the gas is directionally discharged by the exhaust pipe, which can avoid cross-contamination and improve the hydrogen recovery rate.

[0060] (2) This invention significantly improves the efficiency, purity, stability and environmental friendliness of biomass hydrogen production devices through nanomaterial modification, structural integration optimization and resource recycling technology, while reducing energy consumption and maintenance costs, providing an innovative solution for large-scale green hydrogen production.

[0061] (3) This invention achieves a comprehensive improvement in efficiency, purity, lifespan and environmental friendliness of biomass hydrogen production devices through nanomaterial modification, structural innovation and process optimization, providing an efficient, low-cost and sustainable technical solution for the large-scale application of hydrogen energy. Attached Figure Description

[0062] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in this invention. For those skilled in the art, other drawings can be obtained based on these drawings.

[0063] Figure 1 This is a schematic diagram of the overall structure of an embodiment of the nano-enhanced biomass hydrogen production membrane electrode integrated device and preparation method of the present invention.

[0064] Figure 2 This is a schematic diagram of the tank body, tank cover one, and tank cover two provided in an embodiment of the present invention, which describes an integrated device and preparation method for nano-enhanced biomass hydrogen production membrane electrode.

[0065] Figure 3This is a schematic diagram of the tank, reaction zone, oxygen zone, and hydrogen zone structure provided in an embodiment of the nano-enhanced biomass hydrogen production membrane electrode integrated device and preparation method of the present invention.

[0066] Figure 4 This is a schematic diagram of the membrane electrode assembly structure provided in an embodiment of the present invention, which describes a nano-enhanced biomass hydrogen production membrane electrode integrated device and its preparation method.

[0067] Figure 5 This is a schematic diagram of the preparation method provided in an embodiment of the present invention, which describes an integrated device and preparation method for nano-enhanced biomass hydrogen production membrane electrode.

[0068] Figure 6 This invention provides an embodiment of a nano-enhanced biomass hydrogen production membrane electrode integrated device and its preparation method. Schematic diagram of the preparation method.

[0069] Figure 7 This invention provides an embodiment of a nano-enhanced biomass hydrogen production membrane electrode integrated device and its preparation method. Schematic diagram of nanoparticle preparation method.

[0070] Figure 8 This is a schematic diagram of the diffusion membrane preparation method provided in an embodiment of the present invention, which describes a nano-enhanced biomass hydrogen production membrane electrode integrated device and preparation method.

[0071] Figure 9 This is a schematic diagram of the proton exchange membrane preparation method provided in an embodiment of the present invention, which describes a nano-enhanced biomass hydrogen production membrane electrode integrated device and preparation method.

[0072] Figure 10 This is a schematic diagram of the cathode preparation method provided in an embodiment of the present invention, which describes an integrated device and preparation method for a nano-enhanced biomass hydrogen production membrane electrode.

[0073] Explanation of reference numerals in the attached figures:

[0074] 1. Tank body; 2. Exhaust pipe; 3. Tank cover one; 4. Tank cover two; 5. Oxygen zone; 6. Shell; 7. Exhaust port; 8. Membrane electrode assembly; 9. Reaction zone; 10. Hydrogen zone; 11. Filter membrane; 12. Mounting groove; 13. Cathode connector; 14. Anode connector; 15. Return pipe; 16. U-shaped frame; 17. Proton exchange membrane; 18. Honeycomb tube frame; 19. Diffusion membrane; 20. Tube and shell components; 21. Piston head; 22. Injection port; 23. Porous spray pipe; 24. Drain pump. Detailed Implementation

[0075] To enable those skilled in the art to better understand the technical solution of the present invention, the present invention will be further described in detail below with reference to the accompanying drawings.

[0076] like Figure 1-4As shown in the figure, an embodiment of the present invention provides a nano-enhanced biomass hydrogen production membrane electrode integrated device, including a tank 1. Two membrane electrode assemblies 8 are bolted inside the tank 1, and a housing 6 is bolted to one side of the outer wall of each membrane electrode assembly 8. An exhaust port 7 is provided on one side of the outer wall of the housing 6. A reaction zone 9 is formed between the two membrane electrode assemblies 8. One housing 6 is positioned between itself and one side of the inner wall of the tank 1, forming a hydrogen zone 10. The other housing 6 is positioned between itself and the other side of the inner wall of the tank 1, forming an oxygen zone 5. Exhaust pipes 2 are inserted into both sides of the outer wall of the tank 1, with one end of each exhaust pipe extending into the hydrogen zone 10 and the oxygen zone 5, respectively. Each membrane electrode assembly 8 includes a U-shaped frame 16. Inside the U-shaped frame 16, a proton exchange membrane 17, a honeycomb tube frame 18, and a diffusion membrane 19 are respectively installed by bolts. By integrating the proton exchange membrane 17, the honeycomb tube frame 18, and the diffusion membrane 19 into the U-shaped frame 16, a high degree of synergy between catalysis, mass transfer, and separation functions is achieved, improving the biomass conversion efficiency in the reaction zone 9. The honeycomb tube frame 18 is located between the proton exchange membrane 17 and the diffusion membrane 19. The membrane electrode assembly 8 also includes a shell 20. Multiple porous spray pipes 23 are threadedly connected to the outer wall of one side of the bottom of the shell 20. The porous spray pipes 23 cooperate with the injection port 22 to achieve uniform distribution of biomass slurry, avoid local overheating or uneven reactant concentration, improve the stability of hydrogen yield, and the porous spray pipes 23 are also connected to the outer wall of the inner wall of the U-shaped frame 16. 3. Inserted into the honeycomb tube frame 18, the outer wall of the top side of the tube shell 20 has an injection port 22, which facilitates the injection of slurry into the tube shell 20, and a piston head 21 is threaded inside the injection port 22; the outer wall of one side of the tank body 1 has an installation groove 12, and an anode connector 14 and a cathode connector 13 are respectively installed on one side of the inner wall of the installation groove 12 by bolts. A reverse voltage is applied through the anode connector 14 and the cathode connector 13 to electrochemically oxidize and remove carbon deposits on the surface of the honeycomb tube frame 18, thereby improving the catalyst activity recovery rate. The anode connector 14 and the cathode connector 13 are electrically connected to the honeycomb tube frames 18 in the two membrane electrode assemblies 8 respectively; the installation groove 12 A drain pump 24 is bolted to one side of the inner wall. The drain pump 24 is preferably of a certain type. Unreacted biomass slurry in the oxygen zone 5 is sucked out by the drain pump 24 and reinjected into the reaction zone 9 through the return pipe 15, thereby improving the utilization rate of raw materials. The drain pump 24 is connected to the shell 6 through a pipe. The return pipe 15 is inserted into the center of one side of the inner wall of the mounting groove 12, and the other end of the return pipe 15 is installed at the outlet of the drain pump 24. Filter membranes 11 are bolted to the inside of the oxygen zone 5 and the hydrogen zone 10. The hydrogen zone 10 and the oxygen zone 5 are physically isolated by the filter membrane 11. Combined with the exhaust pipe 2, the gas is directionally discharged to avoid cross-contamination and improve the hydrogen recovery rate. One side of the filter membrane 11 is in contact with the shell 6.Both sides of the top outer wall of the tank body 1 are bolted with a tank cover 3, and one side of the top outer wall of the tank body 1 is bolted with a tank cover 4. Unscrewing the tank cover 4 and the tank cover 3 facilitates maintenance of the internal structure of the tank body 1, and the tank cover 4 is located between the two tank covers 3.

[0077] A method for preparing a nano-enhanced biomass hydrogen production membrane electrode, such as Figure 5-10 As shown, the process includes the following steps: Step S1. Catalyst preparation: Fe3O4@CNTS is synthesized by a solvothermal method, and Pt nanoparticles are prepared by a chemical reduction method;

[0078] It should be noted that the preparation method of Fe3O4@CNTS in the catalyst preparation process is as follows:

[0079] S1-1. Raw material proportioning and pretreatment

[0080] S1-1.1. Carbon and Nitrogen Precursors: Dicyandiamine (C2H4N4) and glucose (C6H4N4) are reacted... 12 O6) Mixed at a mass ratio of 1:1-1:3 as carbon and nitrogen sources, and then ground and mixed by ball mill at 300 rpm for 2 hours; S1-1.2. Introduction of metal salts: During ball milling, ferric nitrate (Fe(NO3)3∙9H2O) and nickel nitrate (Ni(NO3)2∙6H2O) are added to the ball mill, and the mass ratio of metal salts to the total mass of carbon and nitrogen precursors is 1:5-1:10;

[0081] S1-2. High-temperature calcination process

[0082] S1-2.1. Inert atmosphere carbonization: The mixed powder is placed in a tube furnace and heated to 800-1000℃ at 5℃ / min under a nitrogen atmosphere, and held for 2-4 hours. During this process, glucose is carbonized to form a porous carbon framework, and dicyandiamine decomposes to produce NH3 and HCN, which promotes nitrogen doping.

[0083] S1-2.2. Core-shell structure formation:

[0084] Fe 2+ and Ni 2+ During the carbonization process, it is reduced to FeNi alloy nanoparticles (core) and coated with a nitrogen-doped carbon layer (shell) to form a Fe3O4@CNTS structure. The thickness of the carbon shell is controlled by regulating the heating rate and carbonization time.

[0085] S1-3. Post-processing optimization

[0086] S1-3.1. Acid washing and purification: The calcined product was immersed in 0.5M H2SO4 and ultrasonically treated for 6 hours to remove uncoated metal particles and impurities; then acid washed and washed with water until neutral, and vacuum dried at 80℃ for 12 hours.

[0087] S1-3.2. Graphene composite: Fe3O4@CNTS and graphene oxide are mixed at a mass ratio of 1:2, and then fed into a calcination furnace and calcined for 1 hour at 800℃ to form a graphene support structure.

[0088] The preparation method of nanoparticles is as follows:

[0089] Step S2-1. Heat the hexachloroplatinic acid (H2PtCl6) solution to boiling, and then quickly inject the reducing agent solution (a mixture of NaBH4 and citric acid).

[0090] Step S2-2. After reacting for 10 minutes, cool the mixture. After cooling, pour the mixture into a centrifuge, start the centrifuge, and centrifuge to obtain Pt nanoparticles (particle size <10 nm).

[0091] Step S2. Anode preparation:

[0092] Step S2.1. Raw material acquisition and processing: Collect biomass materials such as straw and rice husks, and then carry out crushing-washing-washing steps to obtain neutral biomass materials. When crushing, rice husks and straw biomass need to be crushed to 100-200 mesh. When washing, use 10% HNO3 solution.

[0093] Step S2.2. Carbonization and pulverization: The obtained neutral biomass material is placed in a tube furnace and the tube furnace is started for carbonization. During carbonization, the atmosphere is argon, the temperature is 800℃, and the time is 2 hours. After carbonization, a porous carbon carrier with a specific surface area >1200m² / g is obtained. After carbonization, the carbonized material is taken out and put into a ball mill for pulverization.

[0094] Step S2.3. Impregnation and molding: Prepare catalyst slurry, put the crushed carbonized material into the catalyst slurry for impregnation, after impregnation, take out the carbonized material and mix it with the binder. The binder is an adhesive with metal powder. After mixing, put it into the mold for molding. After completion, take out the workpiece and use machining equipment for finishing.

[0095] Step S2.4. Etching and Synthesis: The nanocomposite catalyst slurry is sprayed onto a porous titanium substrate and annealed to form a gradient pore structure, thus obtaining the anode. Then, staggered trenches are etched on the surface of the anode catalyst layer using a laser (the etched trenches are 150 μm wide, 50 μm deep, and 300 μm apart), with a channel density of 15 cm / cm².

[0096] Step S3. Diffusion film preparation: Titanium fibers are selected and bonded together using an adhesive. After bonding, the fibers are placed in a mold and cold-pressed. After molding, the fibers are placed in a sintering device for sintering. After sintering, the diffusion film is obtained. The specific method for preparing the diffusion film is shown below:

[0097] Step S3-1. Raw material preparation: Select high-purity titanium fiber, and pickle the high-purity titanium fiber with 5% HNO3 solution, and then use polyvinyl alcohol to bond the high-purity titanium fiber.

[0098] Step S3-2. Fiber layup and pre-compression molding: Titanium fibers are evenly laid in the mold with an initial layup thickness of about 1.2-1.5 mm. The fibers are then vibrated and screened to ensure uniform distribution. The fibers are then cold-compressed under a pressure of 200-300 MPa to form a preliminary porous structure with a thickness of about 0.8-1.0 mm after pre-compression.

[0099] Step S3-3. Vacuum sintering: Place the pre-pressed billet in a vacuum sintering furnace, with a heating rate of 5-10℃ / min, a target temperature of 1200-1350℃, and a holding time of 2-4 hours. Argon or high-purity nitrogen is introduced throughout the process to protect against oxidation.

[0100] Step S3-4. Post-treatment and finishing: The surface of the sintered billet is treated by pickling and passivation, water washing and drying techniques.

[0101] Step S4. Proton exchange membrane preparation: Sulfonated polyether ether ketone doped with 5-10 wt% nano-sized... After being cast into a film, it is then hot-pressed and cured to form a proton exchange membrane; the specific methods for preparing the proton exchange membrane are as follows:

[0102] Step S4-1. Nanomaterial selection: Select silica, layered double hydroxide or carbon-based nanomaterials as dopants, control the particle size to 20-100nm, and acidify the hydrophobic nanomaterials such as carbon-based nanomaterials. After acidification, add the nanomaterials to DMSO solvent at a ratio of 5-10wt% and sonicate for 1-2 hours.

[0103] Step S4-2. SPEEK solution preparation and blending: Dissolve polyether ether ketone (PEEK) in 98% concentrated sulfuric acid, control the sulfonation temperature at 60-80℃ and the reaction time at 4-6 hours, adjust the degree of sulfonation (DS) to 60-70%, then separate the product by ice-water precipitation, wash until neutral and vacuum dry, then dissolve SPEEK in DMSO solution (concentration 8-12wt%), add the pretreated nano-dispersion, heat to 60℃ and mechanically stir for 4 hours to form a homogeneous mixed solution;

[0104] Step S4-3. Casting and Hot Pressing Curing: The mixed solution is cast onto a clean glass substrate. The wet film thickness is controlled by a scraper to be 0.3-0.5 mm. The solvent is evaporated at room temperature for 12 hours. Then, it is transferred to a vacuum drying oven (60℃, 6 hours) to completely remove residual solvent. After that, the nascent film is placed in a hot press, and the temperature is set to 120-140℃ and the pressure to be 5-10 MPa. The temperature and pressure are maintained for 30-60 minutes to promote the interfacial bonding between the nanomaterials and SPEEK. After cooling, the film is peeled off to obtain a final film thickness of 50-100 μm.

[0105] Step S5. Cathode preparation: Nanoparticles were anchored to nitrogen-doped carbon fibers using electrospinning technology, followed by heat treatment to obtain the cathode; the specific method for cathode preparation is shown below:

[0106] Step S5-1. Preparation of precursor spinning solution: Dissolve nitrogen-containing precursor and Pt precursor in organic solvent to form a uniform spinning solution. Then, add nitrogen-containing compound to provide abundant nitrogen sites for carbon fiber and enhance Pt anchoring ability.

[0107] Step S5-2. Electrospinning to prepare fiber precursor: Pour the silk solution into the electrospinning machine, start the electrospinning machine, set the voltage to 12-20kV, the feed speed to 0.5-2mL / h, and the spinning distance to 10-16cm to form continuous nanofibers with a diameter of 100-500nm. Then, use a polytetrafluoroethylene membrane to prevent the fibers from sticking together.

[0108] Step S5-3. Heat treatment and carbonization: Heat at 180-250℃ in air for 1-4 hours to stabilize the fiber morphology and promote the formation of nitrogen-containing functional groups. Then calcine at 700-1000℃ in an inert atmosphere for 1-4 hours to convert the polymer into nitrogen-doped carbon fibers (N-CNFs). At the same time, the Pt precursor is reduced in situ to Pt nanoparticles (particle size <5nm).

[0109] Step S5-4. Pt nanoparticle anchoring optimization: Through the strong interaction between C and N atoms and Pt during carbonization, Pt particles are uniformly dispersed on the fiber surface and internal pores. Impurities are removed by hydrogen reduction or acid washing to further expose Pt active sites and enhance electrochemical activity.

[0110] Step S6. Membrane electrode assembly: Combine the obtained cathode and anode with the prepared diffusion membrane and proton exchange membrane, arranged from the outside to the inside as proton exchange membrane, cathode / anode, and diffusion membrane, and then combine them together through a hot pressing molding process.

[0111] Example 1

[0112] The preparation method of Fe3O4@CNTS is as follows:

[0113] A1: Mix dicyandiamine (30g) and glucose (30g) in a 1:1 ratio and ball mill (300rpm, 2h).

[0114] A2: Add ferric nitrate (4.8g) and nickel nitrate (3.2g), with a metal salt to carbon-nitrogen precursor mass ratio of 1:8.

[0115] A3: Under nitrogen atmosphere, the temperature is increased to 900℃ at 5℃ / min and held for 3h to generate FeNi alloy core-nitrogen-doped carbon shell (shell thickness -5nm).

[0116] A4: Pickling (6h 1MHCl) to remove uncoated metal, followed by washing and drying.

[0117] A5: Mixed with graphene oxide (GO) at a ratio of 1:2 and calcined at 900℃ for 1 hour to form Fe3O4@CNTS composite catalyst.

[0118] performance

[0119] Specific surface area: 1120 m² / g (40% higher than that of uncomposite graphene);

[0120] Catalytic activity: Hydrogen production rate reaches 28 L / h·g (Fe3O4@CNTS standard is 20 L / h·g);

[0121] Stability: 98% activity retention rate after 1000 hours of operation (compared to <90% for conventional catalysts).

[0122] Example 2

[0123] The specific method for anode preparation is as follows:

[0124] B1: Rice husks were crushed to 150 mesh, washed with 10% NaOH, and then carbonized (800℃, Ar, 2h) to obtain porous carbon with a specific surface area of ​​1350m² / g.

[0125] B2: Impregnate Fe3O4@CNTS slurry (solid content 30%), mix with 5% Ag powder adhesive, and press into shape.

[0126] B3: Laser-etched trenches (150μm wide, 50μm deep, 300μm spacing), channel density 15cm / cm².

[0127] performance

[0128] Current density: 2.5A / cm² (1.2A / cm² for unetched anode);

[0129] Mass transfer efficiency: The trench structure increases the biomass diffusion rate by 70%;

[0130] Anti-carbon buildup capability: 99.5% activity recovery rate after reverse voltage removal (compared to <95% for traditional anodes).

[0131] Example 3

[0132] The method for preparing proton exchange membranes is as follows:

[0133] C1: Select TiO2 (50nm) and SiO2 (30nm) mixed in a 1:1 ratio and acidified (HNO3 / H2SO4, 1:3).

[0134] C2: SPEEK sulfonation degree 65% (reacted at 60℃ for 5h), blended with 8wt% nanoparticles (DMSO, stirred at 60℃ for 4h).

[0135] C3: Cast film (wet film thickness 0.4 mm), hot-pressed at 120℃ (8 MPa, 45 min), final film thickness 80 μm.

[0136] performance

[0137] Proton conductivity: 0.18 S / cm (0.10 S / cm for pure SPEEK membrane).

[0138] Methanol resistance: Methanol permeability coefficient 3.2 × 10⁻ 7 cm² / s (pure SPEEK membrane 9.5×10⁻) 7 cm² / s);

[0139] Mechanical strength: Tensile strength 45MPa (30MPa for pure SPEEK film).

[0140] Existing technology control group: Catalyst: Commercial Pt / C (20wt% Pt); Anode: Unetched porous carbon;

[0141] Proton membrane: Nafion117.

[0142] The following charts can be obtained by comparing Example 1, Example 2, Example 3, and the prior art:

[0143]

[0144] As shown in the table above, Examples 1, 2 and 3 significantly improve hydrogen production efficiency, reduce costs and extend lifespan through material composites, structural design and process optimization, and are applicable to fields such as agricultural waste resource utilization and green hydrogen production.

[0145] Working principle: When this device is used, the biomass slurry in reaction zone 9 undergoes electrocatalytic oxidation under the action of the Fe3O4@CNTS nanocatalyst in the honeycomb tube frame 18, producing... The H gas migrates through the proton exchange membrane 17 to the hydrogen region 10, and then migrates to the membrane electrode assembly 8 corresponding to the cathode connector 13. + Hydrogen gas is generated by combining with electrons on the surface of the diffusion membrane 19. At the same time, water molecules will undergo hydrogen evolution reaction at the membrane electrode assembly 8 corresponding to the cathode connector 13. The generated hydrogen gas will diffuse through the diffusion membrane 19 to the hydrogen zone 10, and then be intercepted by the filter membrane 11 to remove residual carbon dioxide and organic vapors. Finally, it will be output through the exhaust pipe 2. The oxygen and a small amount of unreacted carbon dioxide inside the oxygen zone 5 will be filtered by the filter membrane 11 on the other side and discharged to avoid gas back mixing. The unreacted biomass slurry in the oxygen zone 5 will be sucked by the drainage pump 24 and reinjected into the reaction zone 9 through the return pipe 15 to improve the utilization rate of raw materials. At the same time, after pretreatment, the biomass raw materials will be injected into the tube shell 20 through the injection port 22 and evenly sprayed onto the surface of the honeycomb tube frame 18 by the porous spray pipe 23. Every 1000 hours of operation, a reverse voltage is applied through the anode connector 14 to electrochemically oxidize and remove the carbon deposits on the surface of the honeycomb tube frame 18, thereby improving the catalyst activity recovery rate.

[0146] The foregoing has only described certain exemplary embodiments of the present invention by way of illustration. Undoubtedly, those skilled in the art can modify the described embodiments in various ways without departing from the spirit and scope of the present invention. Therefore, the foregoing drawings and descriptions are illustrative in nature and should not be construed as limiting the scope of protection of the claims of the present invention.

Claims

1. A nano-enhanced biomass hydrogen production membrane electrode integrated device, comprising a tank body (1), characterized in that: The tank body (1) is internally provided with two membrane electrode assemblies (8) which are bolted, and the outer wall of one side of the membrane electrode assembly (8) is provided with a shell (6) which is bolted, the outer wall of one side of the shell (6) is provided with an exhaust hole (7), the reaction zone (9) is between the two membrane electrode assemblies (8), one of the shell (6) and the inner wall of one side of the tank body (1) is the hydrogen zone (10), the other shell (6) and the other side of the inner wall of the tank body (1) is the oxygen zone (5), the outer wall of both sides of the tank body (1) is inserted with an exhaust pipe (2), and the two exhaust pipes (2) extend to the inside of the hydrogen zone (10) and the oxygen zone (5) respectively. The membrane electrode assembly (8) comprises a U-shaped frame (16), the inner part of the U-shaped frame (16) is respectively provided with a proton exchange membrane (17), a honeycomb tube frame (18) and a diffusion membrane (19) which are bolted, and the honeycomb tube frame (18) is located between the proton exchange membrane (17) and the diffusion membrane (19). The membrane electrode assembly (8) further comprises a tube shell (20), the bottom of one side of the tube shell (20) is threadedly connected with a plurality of porous spray pipes (23), and the porous spray pipes (23) are inserted into the honeycomb tube frame (18), the top of one side of the tube shell (20) is provided with an injection port (22), and the injection port (22) is threadedly connected with a piston head (21) inside. The proton exchange membrane (17) is made of sulfonated polyether ether ketone doped with nano TiO2 particles, the honeycomb tube frame (18) is made of a porous carbon carrier sprayed with a catalyst slurry, and the diffusion membrane (19) is made of a titanium fiber sintered porous titanium plate.

2. The nano-enhanced biomass hydrogen production membrane electrode integrated device according to claim 1, wherein, The outer wall of one side of the tank body (1) is provided with a mounting groove (12), and the inner wall of one side of the mounting groove (12) is respectively provided with an anode connecting seat (14) and a cathode connecting seat (13) which are bolted, the anode connecting seat (14) and the cathode connecting seat (13) are respectively electrically connected with the honeycomb tube frame (18) in the two membrane electrode assemblies (8).

3. The nano-enhanced biomass hydrogen production membrane electrode integrated device according to claim 2, wherein, The inner wall of one side of the mounting groove (12) is provided with a drainage pump (24) which is bolted, and the drainage pump (24) is in communication with the shell (6) through a pipeline, the inner wall of one side of the mounting groove (12) is inserted with a return pipe (15), and the other end of the return pipe (15) is installed at the water outlet of the drainage pump (24).

4. The nano-enhanced biomass hydrogen production membrane electrode integrated device according to claim 1, wherein, The inner part of the oxygen zone (5) and the hydrogen zone (10) is provided with a filter membrane (11) which is bolted, and one side of the filter membrane (11) is in contact with the shell (6).

5. The nano-enhanced biomass hydrogen production membrane electrode integrated device according to claim 1, wherein, The outer wall of both sides of the top of the tank body (1) is provided with a tank cover one (3) which is bolted, the outer wall of one side of the top of the tank body (1) is provided with a tank cover two (4) which is bolted, and the tank cover two (4) is located between the two tank cover ones (3).

6. A preparation method of a nano-enhanced biomass hydrogen production membrane electrode, wherein the membrane electrode prepared by the method is applied to the nano-enhanced biomass hydrogen production membrane electrode integrated device according to any one of claims 1-5, characterized in that, The steps include: Step S1. Catalyst preparation: Fe3O4@CNTS is synthesized by solvothermal method, and Pt nanoparticles are prepared by chemical reduction method; Step S2. Anode preparation: Step S2.

1. Raw material acquisition and processing: collect straw and rice hull biomass materials, then perform the steps of crushing, cleaning and washing to obtain neutral biomass materials; Step S2.

2. Carbonization and pulverization: Put the obtained neutral biomass material into a tube furnace, start the tube furnace for carbonization treatment, after carbonization, take out the carbonized material and put it into a ball mill for pulverization treatment; Step S2.

3. Immersion and molding: Configure the catalyst slurry, put the pulverized carbonized material into the catalyst slurry for immersion, after immersion, take out the carbonized material and mix with the adhesive, after mixing, put it into the mold for molding, after molding, take out the workpiece and use machining equipment for modification treatment; Step S2.

4. Etching and synthesis: Spray the nanocomposite catalyst slurry to the porous titanium substrate, form a gradient pore structure after annealing, get the anode, and then etch the staggered grooves on the surface of the anode catalyst layer by laser; Step S3. Diffusion membrane preparation: Select titanium fibers and bond them together using an adhesive. After bonding, cold-press the fibers into a mold. After molding, place the fibers into a sintering device for sintering. After sintering, obtain the diffusion membrane. Step S4. Proton exchange membrane preparation: Sulfonated polyether ether ketone is doped with 5-10wt% nano TiO2. After casting and film formation, heat and press to cure, forming a proton exchange membrane. Step S5. Cathode preparation: Pt nanoparticles are anchored on nitrogen-doped carbon fibers by electrospinning technology, and then heat-treated to obtain a cathode. Step S6. Membrane electrode assembly: The obtained cathode, anode, diffusion membrane, and proton exchange membrane are combined together, with the proton exchange membrane, cathode / anode, and diffusion membrane from outside to inside, and then combined together by hot-pressing molding process. In the step S1 catalyst preparation process, the Fe3O4@CNTS preparation method is as follows:

7. The method of claim 6, wherein the method further comprises the step of: S1-1. Raw material ratio and pretreatment S1-1.

2. Metal salt introduction: When mixing in the ball mill, add iron nitrate and nickel nitrate to the ball mill, and the total mass ratio of metal salt to carbon-nitrogen precursor is 1:5-1:10; S1-1.

1. Carbon-nitrogen precursor: dicyandiamide C2H4N4 is mixed with glucose C6H 12 O6 in a mass ratio of 1:1-1:3 as carbon source and nitrogen source, and then ground by a ball mill. The grinding speed is 300 rpm, and the grinding time is 2 hours. S1-2. High-temperature calcination process S1-2.

1. Inert atmosphere carbonization: Put the mixed powder into a tube furnace, heat to 800-1000℃ at 5℃ / min under nitrogen atmosphere, and keep for 2-4 hours. In this process, glucose is carbonized to form a porous carbon skeleton, and dicyandiamide decomposes to produce NH3 and HCN, promoting nitrogen doping; S1-2.

2. Core-shell structure formation S1-3. Post-treatment optimization Fe 2+ and Ni 2+ are reduced to FeNi alloy nanoparticle cores during carbonization and are coated with a nitrogen-doped carbon shell layer to form structures, the carbon shell thickness is controlled by regulating the heating rate and carbonization time; S1-3.

1. Acid pickling purification: Soak the calcined product in 0.5M H2SO4 for 6 hours under ultrasonic treatment to remove uncoated metal particles and impurities; after acid pickling, wash to neutral, and vacuum dry at 80℃ for 12 hours; Step S2-1. Heat the hexachloroplatinic acid H2PtCl6 solution to boiling, then quickly inject the reducing agent solution, which is a mixture of NaBH4 and citric acid; S1-3.

2. Graphene Composite: [The text abruptly ends here, likely due to an incomplete sentence or It is mixed with graphene oxide at a mass ratio of 1:2, and then fed into a calcination furnace for a second calcination at 800℃ for 1 hour to form a graphene support structure. The nanoparticles were prepared as follows: Step S2-2. Cool for 10 minutes, then pour into a centrifuge and start the centrifuge to obtain Pt nanoparticles with a particle size <10nm. ​ 8. The method of claim 6, wherein the method further comprises the step of: In step S2.1, the raw materials are obtained and processed, in which the rice husk and straw biomass are crushed to 100-200 mesh, and 10% HNO3 solution is used for cleaning; In step S2.2, carbonization and crushing, the carbonization is carried out in an argon atmosphere at a temperature of 800°C for 2 hours, and a porous carbon carrier with a specific surface area of >1200 m² / g is obtained after carbonization; In step S2.3, impregnation and molding, the adhesive is selected to be an adhesive with metal powder; In step S2.4, etching and synthesis, the etched grooves have a width of 150 μm, a depth of 50 μm, and a pitch of 300 μm, and the flow channel density reaches 15 cm / cm².

9. The method of claim 6, wherein the method further comprises the step of: The step S3 diffusion membrane preparation method is specifically as follows: ​ Step S3-1. Preparation of raw materials: high-purity titanium fibers are selected, and the high-purity titanium fibers are subjected to acid pickling by 5% solution, and then the high-purity titanium fibers are subjected to bonding by polyvinyl alcohol; Step S3-2. Fiber layering and pre-pressing: uniformly lay titanium fibers in the mold, the initial layer thickness is 1.2-1.5 mm, and the fiber distribution is ensured to be uniform by vibration screening, then cold pressing is performed under a pressure of 200-300 MPa to form a preliminary porous structure, and the thickness after pre-pressing is 0.8-1.0 mm; Step S3-3. Vacuum sintering: place the pre-pressed body in a vacuum sintering furnace, the heating rate is 5-10°C / min, the target temperature is 1200-1350°C, the holding time is 2-4 hours, and argon or high-purity nitrogen is introduced throughout the process to avoid oxidation; Step S3-4. Post-processing and finishing: the surface of the sintered body is treated by acid pickling, passivation, water washing and drying technology; The step S4 proton exchange membrane preparation method is specifically as follows: Step S4-1. Nanomaterial selection: select silica, layered double hydroxide or carbon-based nanomaterial as a dopant, control the particle size to be 20-100 nm, and acidify the hydrophobic nanomaterial, after acidification, add the nanomaterial to DMSO solvent at a proportion of 5-10 wt%, and ultrasonic treat for 1-2 hours; Step S4-2. SPEEK solution preparation and blending: dissolve polyether ether ketone PEEK in 98% concentrated sulfuric acid, control the sulfonation temperature to be 60-80°C, the reaction time to be 4-6 hours, adjust the sulfonation degree DS to be 60-70%, then separate the product by ice water precipitation method, wash to neutral, vacuum dry, then dissolve SPEEK in DMSO solution, the concentration of the DMSO solution is 8-12 wt%, add the pretreated nanodispersion, heat to 60°C, mechanically stir for 4 hours to form a homogeneous mixed solution; Step S4-3. Casting and hot pressing: cast the mixed solution on a clean glass plate substrate, control the wet film thickness to be 0.3-0.5 mm by scraper, volatilize the solvent at room temperature for 12 hours, then transfer to a vacuum drying box to completely remove the residual solvent, then place the nascent film in a hot press, set the temperature to be 120-140°C, the pressure to be 5-10 MPa, and the holding time to be 30-60 minutes, promote the interface bonding of the nanomaterial and SPEEK, peel off after cooling, and obtain the final film thickness of 50-100 μm. The step S5 cathode preparation method is specifically as shown below: Step S5-1. Preparation of precursor solution: the nitrogen-containing precursor and Pt precursor are dissolved in an organic solvent to form a uniform spinning solution, and then a nitrogen-containing compound is added to provide abundant nitrogen sites for carbon fibers and enhance the Pt anchoring capacity; Step S5-2. Preparation of fiber precursor by electrospinning: pour the spinning solution into an electrospinning machine, start the electrospinning machine, the voltage is 12-20 kV, the pushing speed is 0.5-2 mL / h, the spinning distance is 10-16 cm, and continuous nanofibers with a diameter of 100-500 nm are formed, and then a polytetrafluoroethylene film is used to avoid fiber adhesion; Step S5-3. Heat treatment and carbonization: heat at 180-250°C for 1-4h in an air atmosphere to stabilize the fiber morphology and promote the formation of nitrogen-containing functional groups, and then calcine at 700-1000°C for 1-4h in an inert atmosphere to convert the polymer into nitrogen-doped carbon fibers N-CNFs, while reducing the Pt precursor in situ to Pt nanoparticles with a particle size of <5nm; Step S5-4. Pt nanoparticle anchoring optimization: through the strong interaction between C, N atoms and Pt during the carbonization process, the Pt particles are uniformly dispersed on the fiber surface and internal pores, and hydrogen reduction or acid washing is used to remove impurities, further exposing the Pt active sites and improving the electrochemical activity.

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