Preparation method and application of DMF-DMSO complex solvent iron-yttrium bimetallic coordination doped COF hydrogen evolution catalyst
By synthesizing iron-yttrium bimetallic COF structures in situ using a DMF-DMSO composite solvent system and a hydrothermal method, the problems of poor dispersion and insufficient stability of active sites in existing COF-based catalysts have been solved, resulting in a high-efficiency, low-cost hydrogen evolution catalyst suitable for industrial applications.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- NANTONG UNIV
- Filing Date
- 2026-03-30
- Publication Date
- 2026-06-26
AI Technical Summary
Existing COF-based hydrogen evolution catalysts suffer from poor dispersion of active sites and low charge transport efficiency. The synthesis of bimetallic COFs is not optimized in terms of solvent ratio, resulting in low catalytic activity and poor structural stability, making them unsuitable for industrial applications.
Using a DMF-DMSO compound solvent system, an iron-yttrium bimetallic COF structure was synthesized in situ via a hydrothermal method. The ratio of metal source to organic ligand was optimized to achieve uniform dispersion of active sites. The synergistic effect of iron-yttrium bimetal and nickel foam substrate was utilized to enhance catalytic activity and stability.
A high-performance hydrogen evolution catalyst has been developed, with catalytic activity increased by 2 times, excellent stability, low cost, and suitability for industrial applications. Moreover, the preparation process is simple and the reaction conditions are mild, making it suitable for large-scale production.
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Figure CN122279655A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of electrocatalytic hydrogen evolution catalyst technology, and in particular to a method for preparing and applying a DMF-DMSO composite solvent iron-yttrium bimetallic coordination-doped COF hydrogen evolution catalyst. Background Technology
[0002] Hydrogen energy, as a core carrier connecting new energy power generation and end-use energy, is a strategic tool for achieving deep decarbonization in industries and transportation where emissions reduction is difficult, and for ensuring my country's energy self-sufficiency and security. The key to its industrial-scale development lies in the technological upgrade of the water electrolysis hydrogen production process. The core of water electrolysis hydrogen production is the hydrogen evolution reaction (HER) catalyst. Currently, although commercially available platinum-based precious metal catalysts have excellent catalytic activity, they are scarce and expensive, making it difficult to achieve large-scale industrial applications. Non-precious metal catalysts, although inexpensive, generally suffer from low catalytic activity, poor structural stability, and severe performance degradation under high current densities, making them unsuitable for industrial-grade applications.
[0003] Covalent organic frameworks (COFs), as novel crystalline porous materials, possess advantages such as tunable structure, large specific surface area, and regular pore structure, making them a research hotspot for hydrogen evolution catalysts. However, existing COF-based catalysts are mostly monometallic doped or metal-free, exhibiting drawbacks such as poor dispersion of active sites and low charge transport efficiency. Furthermore, the solvent ratio has not been optimized for bimetallic COF synthesis, hindering performance breakthroughs. Therefore, developing high-performance bimetallic COF hydrogen evolution catalysts is crucial for promoting the industrialization of green hydrogen.
[0004] To address the aforementioned issues, this application provides a method for preparing and applying a DMF-DMSO composite solvent iron-yttrium bimetallic coordination-doped COF hydrogen evolution catalyst. Summary of the Invention
[0005] The purpose of this invention is to address the shortcomings of existing technologies by proposing a method for preparing and applying a DMF-DMSO composite solvent iron-yttrium bimetallic coordination-doped COF hydrogen evolution catalyst. This method uses nickel foam as a substrate and synthesizes an iron-yttrium bimetallic COF structure catalyst in situ via a hydrothermal method. It optimizes the ratio of metal source and organic ligands, selects a suitable solvent system, and achieves uniform dispersion of bimetallic active sites. Utilizing the synergistic effect of the iron-yttrium bimetallic catalyst and the synergistic effect of the COF framework and the nickel foam substrate, the hydrogen evolution catalytic activity and stability of the catalyst are improved. Furthermore, the preparation process is simple, the reaction conditions are mild, and it is suitable for large-scale production.
[0006] To achieve the above objectives, the present invention adopts the following technical solution:
[0007] A method for preparing a DMF-DMSO composite solvent iron-yttrium bimetallic coordination-doped COF hydrogen evolution catalyst includes the following steps:
[0008] Step 1, Preparation of metal source solution A: Using iron salt and yttrium salt as metal sources, and DMSO and DMF as reaction media, the metal sources are dissolved together in a certain proportion of the reaction media and stirred until completely dissolved to obtain a homogeneous metal source solution A.
[0009] Step 2, Preparation of organic ligand solution B: Using substituted or unsubstituted aromatic tetracarboxylic dianhydrides and substituted or unsubstituted aromatic diamines as organic ligands, and DMSO and DMF as reaction media, the organic ligands are added sequentially to a certain proportion of the reaction media and stirred until completely dissolved to obtain a homogeneous organic ligand solution B.
[0010] Step 3, Mixing the reaction solution: Slowly add solution A obtained in step 1 to solution B obtained in step 2, and continue stirring to mix evenly. Then add a tertiary amine organic base reaction regulator to the mixture and continue stirring until the system is a homogeneous mixed solution.
[0011] Step 4, Substrate Pretreatment: Clean the surface of the nickel foam to remove surface oxides, oil, and impurities;
[0012] Step 5, hydrothermal reaction: The mixed solution prepared in step 3 is transferred to a high-pressure reactor lined with polytetrafluoroethylene, and the pretreated nickel foam is placed in the reactor as a substrate and the hydrothermal reaction is carried out at a constant temperature.
[0013] Step 6, Post-processing: After the hydrothermal reaction is completed, the reactor is allowed to cool naturally to room temperature. The product is then removed, ultrasonically washed, and vacuum dried to obtain the iron-yttrium bimetallic COF structure hydrogen evolution catalyst.
[0014] Preferably, in step 1, the iron salt is selected from one or more of ferric nitrate, ferric chloride, ferric sulfate, and ferric acetate, and its dosage is based on Fe. 3+ The dosage is 0.5-1 mmol; the yttrium salt is selected from one or more of yttrium nitrate, yttrium chloride, yttrium sulfate, and yttrium acetate, and its amount is expressed as Y. 3+ It is calculated to be 0.1-0.5 mmol.
[0015] Preferably, in step 2, the substituted or unsubstituted aromatic tetracarboxylic dianhydride compound is selected from one or more of pyromellitic dianhydride, 3,3',4,4'-biphenyltetracarboxylic dianhydride, 2,3,6,7-naphthalenetetracarboxylic dianhydride, and 3,3',4,4'-benzophenonetetracarboxylic dianhydride, and is used in an amount of 0.1-0.5 mmol; the substituted or unsubstituted aromatic diamine compound is selected from one or more of m-phenylenediamine, p-phenylenediamine, o-phenylenediamine, and 4,4'-diaminobiphenyl, and is used in an amount of 0.1-0.5 mmol.
[0016] Preferably, in steps 1 and 2, the mixed solvent is a 10-20 ml mixture of DMSO and DMF in a volume ratio of 1:4.
[0017] In step 1, the preferred molar amount of ferric nitrate nonahydrate is 0.5 mmol, the preferred molar amount of yttrium nitrate hexahydrate is 0.2 mmol, the preferred amount of mixed solvent is 10.5 mL, the preferred stirring speed is 300 r / min, and the preferred stirring time is 15 min.
[0018] In step 2, the preferred molar amount of PMDA is 0.3 mmol, the preferred molar amount of MPD is 0.3 mmol, the preferred molar amount of the mixed solvent is 15 mL, the preferred stirring speed is 300 r / min, and the preferred stirring time is 15 min.
[0019] Preferably, in step 3, during the process of adding solution A to solution B, the stirring speed is 300-500 r / min, and stirring continues for 20-30 min after the addition is completed; the tertiary amine organic base reaction regulator is selected from one or more of triethylamine, N,N-diisopropylethylamine, tripropylamine, and tributylamine, and its dosage is 0.05-0.1 ml.
[0020] In step 3, the preferred dropping rate of solution A is 1-2 drops / second, the preferred stirring speed during the dropping process is 300 r / min, and stirring is continued for 20-30 min after the dropping is completed. The preferred volume of TEA is 0.1 mL, and stirring is continued for 3-5 min after adding TEA.
[0021] Preferably, in step 4, the pretreatment of the foamed nickel includes sequential ultrasonic cleaning with ethanol for 15-30 min, ultrasonic cleaning with acetone for 15-30 min, ultrasonic cleaning with 3-5 mol / L hydrochloric acid solution for 5-15 min, and ultrasonic cleaning with deionized water for 15-30 min. After cleaning, it is dried in a vacuum drying oven at 40-60 ℃ for 4-6 h.
[0022] In step 4, the nickel foam is cut to a size of 3 cm × 3 cm. The preferred pretreatment process is as follows: place the nickel foam in ethanol and ultrasonically clean it for 30 min, then place it in acetone and ultrasonically clean it for 30 min, then place it in 3 mol / L dilute hydrochloric acid and ultrasonically clean it for 10 min to remove the surface oxide layer, finally ultrasonically clean it with deionized water for 30 min, and vacuum dry it at 60 ℃ to constant weight for later use.
[0023] Preferably, in step 5, the hydrothermal reaction temperature is 130-150 ℃, and the reaction time is 10-14 h. Specifically, the hydrothermal reaction temperature is preferably 140 ℃, and the reaction time is preferably 12 h.
[0024] Preferably, in step 6, the ultrasonic washing with DMF and ethanol is performed 3-4 times, the vacuum drying temperature is 40-60℃, and the drying time is 4-6 hours. Specifically, the preferred number of ultrasonic washings with DMF and ethanol is 3 times, the preferred washing time for each wash is 5 minutes, the preferred vacuum drying temperature is 60℃, and the preferred drying time is 6 hours.
[0025] This invention also provides an iron-yttrium bimetallic COF structure hydrogen evolution catalyst prepared by the above-described method. This catalyst uses nickel foam as a substrate to grow a highly crystalline COF framework structure in situ, with iron and yttrium bimetallic active sites uniformly dispersed within the COF framework, forming an integrated catalytic electrode. Under conditions of 1 mol / L KOH electrolyte, a three-electrode testing system (saturated calomel electrode as reference electrode and graphite electrode as counter electrode), a scan rate of 5 mV / s with iR compensation, and a catalytic efficiency of 2000 mA / cm², the catalyst exhibits high efficiency. -2 The overpotential at current density is only 517 mV, and its performance at the same overpotential exceeds that of commercial PtC catalysts.
[0026] The present invention also provides an application of the iron-yttrium bimetallic COF structure hydrogen evolution catalyst obtained by the above preparation method in the hydrogen evolution reaction of water electrolysis. The catalyst can be directly used as the working electrode for hydrogen evolution in water electrolysis without the need for additional coating and binder addition. It exhibits excellent hydrogen evolution catalytic performance in alkaline electrolyte and is suitable for the application requirements of industrial water electrolysis hydrogen production.
[0027] Compared with the prior art, the present invention has the following beneficial effects:
[0028] 1. Breakthrough Performance Improvement: This invention uses a 1:4 volume ratio mixture of DMSO and DMF as the reaction solvent. By controlling the polarity and solubility of the solvent, the polymerization rate of the organic ligands is precisely controlled, significantly improving the crystallinity and pore regularity of the COF framework. This provides ample anchoring sites for the metal active sites and effectively prevents metal aggregation. The resulting optimal catalyst achieves a polymerization rate of 2000 mA cm⁻¹. -2 The overpotential at the current density is only 517 mV, which is better than commercial PtC at the same current density. Its performance significantly exceeds that of commercial precious metal catalysts and is 1.67 times that of the control catalyst in pure DMF solvent system.
[0029] 2. Excellent catalytic activity: This invention uses iron and yttrium as bimetallic active sources. By precisely controlling the ratio of metal sources, the electronic synergistic effect between the two metals is achieved, which effectively controls the electronic structure of the active sites and optimizes the hydrogen adsorption free energy of the hydrogen evolution reaction. Compared with the control catalyst doped with single iron and single yttrium, the catalytic activity is increased by 2 times. At the same time, it does not depend on precious metals at all, and the raw material cost is low, which is suitable for the cost control requirements of industrial applications.
[0030] 3. Strong conductivity and stability: This invention uses nickel foam as a substrate and achieves in-situ growth of bimetallic COF catalyst on the surface of nickel foam through hydrothermal method to form an integrated catalytic electrode. This avoids the coverage of active sites caused by the addition of binders and eliminates the interfacial resistance between the catalyst and the substrate, which greatly improves the electron transport efficiency. The three-dimensional porous structure of nickel foam and the pore structure of COF form a multi-level channel, which accelerates the mass transfer process of hydrogen evolution reaction. The catalyst has a strong binding force with the substrate, does not fall off during cycling, and has excellent stability.
[0031] 4. Economical and efficient process: This invention adopts a one-step hydrothermal synthesis method with mild reaction conditions (140 ℃, 12 h), which does not require complex equipment or harsh reaction environment. The raw materials are all common chemical raw materials, which are readily available and cost-controllable. The batch repeatability is good and it is suitable for industrial-scale production. It provides a high-performance and low-cost core catalytic material for the preparation of green hydrogen. Attached Figure Description
[0032] Figure 1 The graph shows the HER performance of FeY-PM (DMSO-DMF), FeY-PM (DMF), Fe-PM, Y-PM, and PM prepared in Example 1 and Comparative Examples 1, 2, 3, and 4 of this invention in 1 mol / L KOH solution.
[0033] Figure 2 The CDL diagrams for FeY-PM (DMSO-DMF), FeY-PM (DMF), Fe-PM, Y-PM, and PM prepared in Examples 1, 2, 3, and 4 of this invention are shown.
[0034] Figure 3 EIS images of FeY-PM (DMSO-DMF), FeY-PM (DMF), Fe-PM, Y-PM, and PM prepared in Example 1 and Comparative Examples 1, 2, 3, and 4 of this invention;
[0035] Figure 4 The TAFEL plots are of FeY-PM (DMSO-DMF), FeY-PM (DMF), Fe-PM, Y-PM, and PM prepared in Examples 1, 2, 3, and 4 of this invention. Detailed Implementation
[0036] The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings, so that those skilled in the art can better understand the advantages and features of the present invention, thereby making a clearer definition of the scope of protection of the present invention. The embodiments described in this invention are only some embodiments of the present invention, not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.
[0037] Example 1
[0038] Preparation of iron-yttrium bimetallic COF structure hydrogen evolution catalyst (optimal experimental group):
[0039] (1) Nickel foam pretreatment:
[0040] The nickel foam was cut into 3 cm × 3 cm pieces and ultrasonically cleaned in ethanol for 30 min, ultrasonically cleaned in acetone for 30 min, ultrasonically cleaned in 3 mol / L dilute hydrochloric acid for 10 min to remove the surface oxide layer. Finally, it was ultrasonically cleaned in deionized water for 30 min and dried in a vacuum drying oven at 60 ℃ until constant weight.
[0041] (2) Preparation of metal source solution A:
[0042] Weigh 0.202 g of ferric nitrate and 0.076 g of yttrium nitrate, and dissolve them together in 10.5 mL of a mixed solvent of DMSO and DMF in a volume ratio of 1:4. Stir at 400 r / min for 15 min until the solid is completely dissolved to obtain a homogeneous and transparent metal source solution A.
[0043] (3) Preparation of organic ligand solution B:
[0044] Weigh 0.065 g PMDA and 0.032 g MPD, and dissolve them together in 15 mL of a mixed solvent of DMSO and DMF in a volume ratio of 1:4. Stir at 400 r / min for 20 min until the solids are completely dissolved to obtain a homogeneous organic ligand solution B.
[0045] (4) Mixed reaction solution:
[0046] Solution A was slowly added to solution B at a rate of 1 drop / second, while stirring continuously at 300 r / min during the addition. After the addition was completed, stirring was continued for 25 min. Then, 0.1 mL of TEA was added to the mixture, and stirring was continued for 5 min until the mixture was completely homogeneous.
[0047] (5) Hydrothermal reaction:
[0048] The above mixed reaction solution was transferred to a 50 mL polytetrafluoroethylene-lined high-pressure reactor. The pretreated nickel foam was placed vertically inside the reactor, ensuring that the mixed reaction solution completely submerged the nickel foam. After sealing the reactor, it was placed in a drying oven and subjected to a hydrothermal reaction at a constant temperature of 140 °C for 12 h.
[0049] (6) Post-processing:
[0050] After the hydrothermal reaction was completed, the reactor was allowed to cool naturally to room temperature. The nickel foam product with catalyst was then removed and ultrasonically washed three times with DMF and ethanol, each time for 5 min. The product was then dried in a vacuum drying oven at 60 ℃ for 6 h to obtain the iron-yttrium bimetallic COF structure hydrogen evolution catalyst, denoted as FeY-PM (DMSO-DMF=1:4).
[0051] Comparative Example 1
[0052] Preparation of iron-yttrium bimetallic COF catalyst in pure DMF solvent system:
[0053] The reaction solvent was replaced with pure DMF, the addition of DMSO was removed, and the amounts and ratios of the metal source and organic ligands, as well as all reaction conditions, were completely consistent with those in Example 1. The resulting catalyst was denoted as FeY-PM(DMF).
[0054] Comparative Example 2
[0055] Preparation of single-metallic iron COF catalyst:
[0056] Using only ferric nitrate as the single metal source, with an amount of 0.2372 g, and yttrium nitrate was omitted, the reaction solvent was a mixture of DMSO and DMF in a volume ratio of 1:4. The amounts and ratios of the other raw materials and all reaction conditions were completely consistent with those in Example 1. The resulting catalyst was denoted as Fe-PM.
[0057] Comparative Example 3
[0058] Preparation of single-metal yttrium COF catalyst:
[0059] Yttrium nitrate was used as the sole metal source, with an amount of 0.2372 g. Ferric nitrate was omitted. The reaction solvent was a mixture of DMSO and DMF in a volume ratio of 1:4. The amounts, ratios, and reaction conditions of the other raw materials were completely consistent with those in Example 1. The resulting catalyst was denoted as Y-PM.
[0060] Comparative Example 4
[0061] Preparation of metal-free COF catalysts:
[0062] The addition of ferric nitrate and yttrium nitrate was omitted, and COF catalyst was synthesized using only pyromellitic dianhydride and m-phenylenediamine as organic ligands. The reaction solvent was a mixture of DMSO and DMF in a volume ratio of 1:4. The amounts and ratios of the remaining raw materials and all reaction conditions were completely consistent with those in Example 1. The resulting catalyst was denoted as PM.
[0063] Performance testing
[0064] The catalysts obtained in Example 1 and Comparative Examples 1-4 were directly used as working electrodes (without additional coating or binder addition). A three-electrode testing system was constructed using the Donghua Electrochemical Workstation, with a saturated calomel electrode as the reference electrode and a graphite electrode as the counter electrode. 1 mol / L potassium hydroxide was used as the electrolyte. The hydrogen evolution reaction (HER) performance of each catalyst was tested by linear sweep voltammetry (LSV) at a scan rate of 5 mV / s. The test results are as follows:
[0065] The HER performance of FeY-PM (DMSO-DMF=1:4), FeY-PM (DMF), Fe-PM, Y-PM, and PM was tested using linear sweep voltammetry, and the resulting polarization curves (LSV plots) are shown in Figure 1. In 1 mol / L potassium hydroxide electrolyte, the overpotential test results showed that at a current density of 2000 mA cm⁻¹... -2 At that time, the overpotential of FeY-PM (DMSO-DMF=1:4) was 517 mV, which was significantly lower than that of FeY-PM (DMF) (621 mV), Fe-PM (723 mV), Y-PM (907 mV) and PM (1070 mV). This directly demonstrates the breakthrough improvement of the catalyst's high-current hydrogen evolution activity by the DMF-DMSO composite solvent + iron-yttrium bimetallic doping.
[0066] Figure 2 shows the capacitance curves characterizing the electrochemical active area (ECSA) of the catalysts corresponding to Example 1 and Comparative Examples 1-4 of this invention. The slope of the curve is the electrochemical double-layer capacitance C. dl (Unit: mF cm) -2 ), C dl Positively correlated with ECSA, C dl A larger value indicates a larger electrochemical active surface area of the catalyst, and a more fully exposed active site. The figure shows the C values of each catalyst. dl Numerical value, C of FeY-PM (DMSO-DMF) dl =13.3 mF cm -2 The highest concentration was found in FeY-PM(DMF), followed by FeY-PM(DMF) (8.2 mF / cm³). -2 ), Fe-PM (6.8 mF cm -2 Y-PM (5.8 mF cm)-2 PM (3.5 mF cm) -2 This result explains the structural reason for the excellent catalyst activity in Example 1: the DMF-DMSO compound solvent improved the crystallinity of the COF framework, the uniform dispersion of the iron-yttrium bimetal provided more active sites, and the in-situ growth structure of the nickel foam allowed the active sites to be fully exposed, laying the foundation for high catalytic activity.
[0067] Figure 3 shows the electrochemical impedance spectroscopy (EIS) Nyquist plots of the catalysts corresponding to Example 1 and Comparative Examples 1-4 of this invention. These plots are used to analyze the interfacial charge transport capability of the catalysts during the electrocatalytic process. The diameter of the semicircle in the high-frequency region of the spectrum is positively correlated with the charge transfer resistance (Rct) of the catalyst. A smaller semicircle diameter indicates a lower charge transfer resistance, higher electron transport efficiency, and less reaction resistance at the catalytic interface. As shown in Figure 3, the semicircle diameter of the FeY-PM(DMSO-DMF) catalyst prepared in this invention is significantly smaller than that of all comparative samples, demonstrating that it possesses the lowest charge transfer resistance. This result is consistent with the process design of the patent. The in-situ growth of the nickel foam substrate and the COF framework forms an integrated catalytic electrode, eliminating the interfacial resistance caused by the binder. The highly crystalline COF framework prepared with the DMF-DMSO compound solvent enhances the electron conductivity, and the synergistic effect of the iron-yttrium bimetal optimizes the charge distribution. Therefore, the charge transport efficiency is far higher than that of the pure DMF solvent, single-metal doped, and metal-free control catalysts.
[0068] Figure 4 shows the Tafel slope spectra of the catalysts corresponding to Example 1 and Comparative Examples 1-4 of this invention, used to characterize the kinetic process of the hydrogen evolution reaction. A smaller Tafel slope indicates faster HER reaction kinetics, a lower reaction energy barrier, and superior catalytic performance. As shown in Figure 4, the Tafel slope of the FeY-PM(DMSO-DMF) catalyst prepared in this invention is 74 mV dec. -1 It is close to the comparison sample Fe-PM (73 mV dec) -1 ), lower than the control sample FeY-PM(DMF) (91mV dec) -1 Y-PM (204 mV dec) -1 ) and PM (145 mV dec -1 The results demonstrate that the electronic synergistic effect of the iron-yttrium bimetal effectively modulates the electronic structure of the active sites, optimizes the hydrogen adsorption free energy of the hydrogen evolution reaction, and makes the HER reaction pathway more efficient. The solvent system of DMF-DMSO compound solvent further enhances this kinetic advantage. Therefore, the catalyst of Example 1 has the fastest hydrogen evolution reaction kinetics.
[0069] The above performance test results fully demonstrate that the catalyst obtained by the present invention through the process design of iron-yttrium bimetallic doping, solvent modification system, and in-situ growth on nickel foam substrate has significantly better hydrogen evolution catalytic activity and stability than pure DMF, single metal doping and metal-free control catalysts, and has significant performance advantages in the field of hydrogen evolution by water electrolysis.
[0070] The descriptions and practices disclosed in this invention are readily apparent and understandable to those skilled in the art, and various modifications and refinements can be made without departing from the principles of this invention. Therefore, any modifications or improvements made without departing from the spirit of this invention should also be considered within the scope of protection of this invention.
Claims
1. A method for preparing a DMF-DMSO composite solvent iron-yttrium bimetallic coordination-doped COF hydrogen evolution catalyst, characterized in that, Includes the following steps: Step 1, Preparation of metal source solution A: Using iron salt and yttrium salt as metal sources, and DMSO and DMF as reaction media, the metal sources are dissolved together in a certain proportion of the reaction media and stirred until completely dissolved to obtain a homogeneous metal source solution A. Step 2, Preparation of organic ligand solution B: Using substituted or unsubstituted aromatic tetracarboxylic dianhydrides and substituted or unsubstituted aromatic diamines as organic ligands, and DMSO and DMF as reaction media, the organic ligands are added sequentially to a certain proportion of the reaction media and stirred until completely dissolved to obtain a homogeneous organic ligand solution B. Step 3, Mixing the reaction solution: Slowly add solution A obtained in step 1 to solution B obtained in step 2, and continue stirring to mix evenly. Then add a tertiary amine organic base reaction regulator to the mixture and continue stirring until the system is a homogeneous mixed solution. Step 4, Substrate Pretreatment: Clean the surface of the nickel foam to remove surface oxides, oil, and impurities; Step 5, hydrothermal reaction: The mixed solution prepared in step 3 is transferred to a high-pressure reactor lined with polytetrafluoroethylene, and the pretreated nickel foam is placed in the reactor as a substrate and the hydrothermal reaction is carried out at a constant temperature. Step 6, Post-processing: After the hydrothermal reaction is completed, the reactor is allowed to cool naturally to room temperature. The product is then removed, ultrasonically washed, and vacuum dried to obtain the iron-yttrium bimetallic COF structure hydrogen evolution catalyst.
2. The preparation method of the DMF-DMSO composite solvent iron-yttrium bimetallic coordination-doped COF hydrogen evolution catalyst according to claim 1, characterized in that, In step 1, the iron salt is selected from one or more of ferric nitrate, ferric chloride, ferric sulfate, and ferric acetate, and its dosage is based on Fe. 3+ The dosage is 0.5-1 mmol; the yttrium salt is selected from one or more of yttrium nitrate, yttrium chloride, yttrium sulfate, and yttrium acetate, and its amount is expressed as Y. 3+ It is calculated to be 0.1-0.5 mmol.
3. The preparation method of the DMF-DMSO composite solvent iron-yttrium bimetallic coordination-doped COF hydrogen evolution catalyst according to claim 1, characterized in that, In step 2, the substituted or unsubstituted aromatic tetracarboxylic dianhydride compound is selected from one or more of pyromellitic dianhydride, 3,3',4,4'-biphenyltetracarboxylic dianhydride, 2,3,6,7-naphthalenetetracarboxylic dianhydride, and 3,3',4,4'-benzophenonetetracarboxylic dianhydride, and is used in an amount of 0.1-0.5 mmol; the substituted or unsubstituted aromatic diamine compound is selected from one or more of m-phenylenediamine, p-phenylenediamine, o-phenylenediamine, and 4,4'-diaminobiphenyl, and is used in an amount of 0.1-0.5 mmol.
4. The preparation method of a DMF-DMSO composite solvent iron-yttrium bimetallic coordination-doped COF hydrogen evolution catalyst according to claim 1, characterized in that, In steps 1 and 2, the mixed solvent is a 10-20 ml mixture of DMSO and DMF in a volume ratio of 1:
4.
5. The preparation method of a DMF-DMSO composite solvent iron-yttrium bimetallic coordination-doped COF hydrogen evolution catalyst according to claim 1, characterized in that, In step 3, during the process of adding solution A to solution B, the stirring speed is 300-500 r / min, and stirring continues for 20-30 min after the addition is completed; the tertiary amine organic base reaction regulator is selected from one or more of triethylamine, N,N-diisopropylethylamine, tripropylamine, and tributylamine, and its dosage is 0.05-0.1 ml.
6. The preparation method of a DMF-DMSO composite solvent iron-yttrium bimetallic coordination-doped COF hydrogen evolution catalyst according to claim 1, characterized in that, In step 4, the pretreatment of the nickel foam includes sequential ultrasonic cleaning with ethanol for 15-30 min, ultrasonic cleaning with acetone for 15-30 min, ultrasonic cleaning with 3-5 mol / L hydrochloric acid solution for 5-15 min, and ultrasonic cleaning with deionized water for 15-30 min. After cleaning, it is dried in a vacuum drying oven at 40-60 ℃ for 4-6 h.
7. The preparation method of a DMF-DMSO composite solvent iron-yttrium bimetallic coordination-doped COF hydrogen evolution catalyst according to claim 1, characterized in that, In step 5, the hydrothermal reaction temperature is 130-150 ℃, and the reaction time is 10-14 h.
8. The preparation method of a DMF-DMSO composite solvent iron-yttrium bimetallic coordination-doped COF hydrogen evolution catalyst according to claim 1, characterized in that, In step 6, the ultrasonic washing with DMF and ethanol is performed 3-4 times, the vacuum drying temperature is 40-60 ℃, and the drying time is 4-6 h.
9. A hydrogen evolution catalyst with an iron-yttrium bimetallic COF structure obtained by the preparation method according to any one of claims 1-8, characterized in that, This catalyst utilizes a highly crystalline COF framework grown in situ on a nickel foam substrate. Iron and yttrium bimetallic active sites are uniformly dispersed within the COF framework, forming an integrated catalytic electrode. Under conditions of 1 mol / L KOH electrolyte, a three-electrode testing system, a scan rate of 5 mV / s with iR compensation, and a catalytic activity of 2000 mA cm⁻¹, it achieves high performance. -2 The overpotential at the current density is only 517 mV.
10. The application of an iron-yttrium bimetallic COF structured hydrogen evolution catalyst obtained by the preparation method according to any one of claims 1-8 in the hydrogen evolution reaction of water electrolysis.