WxNy / Fe3Ni-coated C self-supporting catalyst as well as preparation method and application thereof
By using WxNy/Fe3Ni@C self-supporting catalyst in electrolytic water hydrogen production technology, the problem of slow kinetics of oxygen evolution reaction and easy agglomeration of powder catalysts is solved, and efficient and stable hydrogen production is achieved.
Patent Information
- Application Number
- CN202510341925.0
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-03-21
- Publication Date
- 2025-07-01
AI Technical Summary
In the existing electrolytic hydrogen production technology, the kinetic characteristics of the oxygen evolution reaction are slow and require a high overpotential. The powdered catalyst is prone to agglomeration during use and the active ingredients are easily lost.
The precursor material with nanomorphology of ceramide was prepared by using WxNy/Fe3Ni@C self-supporting catalyst, and a polydopamine-encapsulated carbon paper was used to wrap carbon paper as a substrate, combining phosphotungstic acid and nickel-iron MOF nanomaterials. After calcination, composite materials with excellent conductivity and oxygen evolution catalytic activity were obtained.
The rate and stability of the oxygen evolution reaction are significantly improved, the overpotential requirement is reduced, the aggregation problem of powder catalysts is avoided, and the mechanical strength and chemical activity of the catalyst are improved.
Smart Images
Figure CN120231083A_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to the technical field of hydrogen production by electrolyzing water, and particularly relates to a W x N y / Fe3Ni@C self-supporting catalyst and its preparation method and application. Background Art
[0002] With the increasing global demand for renewable and clean energy, hydrogen energy technology has attracted much attention due to its clean and efficient characteristics. As a clean fuel, hydrogen energy is considered a potential solution to global energy and environmental problems. The technology of hydrogen production by electrolyzing water is one of the main technologies for producing hydrogen currently.
[0003] Hydrogen production by electrolyzing water is a process of decomposing water into hydrogen and oxygen by using an electric current. By passing a direct current through water, water molecules are dissociated under the action of the current to generate oxygen and hydrogen, which are respectively precipitated from the anode and cathode of the electrolytic cell. In the process of hydrogen production by electrolyzing water, the hydrogen evolution reaction (HER) and the oxygen evolution reaction (OER) are key steps. However, the oxygen evolution reaction usually has slow kinetic characteristics and requires a relatively high overpotential to drive. The introduction of a catalyst can significantly reduce the activation energy of the reaction, thereby accelerating the reaction rate and improving the efficiency of hydrogen production by electrolyzing water. By developing efficient electrolyzed water catalysts, the hydrogen production process by electrolyzing water can be further optimized, and the purity and yield of hydrogen and oxygen can be improved.
[0004] Powdery catalysts are prone to agglomeration during use, and the use of dispersants such as naphthol during testing will cause loss of active ingredients. MOF materials have a unique crystal structure, which is a three-dimensional network structure formed by metal ions or metal clusters connected with organic ligands through coordination bonds. This structure can form a large number of pores, thereby having a relatively high specific surface area. In the field of electrocatalysis, the high specific surface area and porosity of MOF materials provide abundant active sites for electrocatalytic reactions and have broad development prospects. However, MOF materials have poor conductivity and insufficient catalytic active sites. By changing the structure of the ligand, more active functional groups can be introduced or the coordination environment of the metal node can be changed, thereby increasing the catalytic sites. It is also possible to improve its inherent conductivity by optimizing the crystal structure of MOFs.
[0005] It should be noted that the above introduction of the technical background is only for the convenience of clearly and completely explaining the technical solutions of the present application and facilitating the understanding of those skilled in the art. It cannot be considered that the above technical solutions are well-known to those skilled in the art just because these solutions are described in the background art part of the present application. Summary of the Invention
[0006] In view of the above deficiencies currently existing, the present invention provides a W x Ny / Fe3Ni@C self-supporting catalyst and its preparation method and application. In the present invention, carbon paper wrapped with polydopamine is used, and phosphotungstic acid is used as a tungsten source to incorporate nickel-iron MOF nanomaterials. The prepared precursor material presents a regular Hericium erinaceus nanomorphology. The Hericium erinaceus-like nanomorphology has a large specific surface area, extremely high chemical activity and structural stability. After calcination, the obtained composite material (W x N y / Fe3Ni@C self-supporting catalyst) has excellent electrical conductivity, oxygen evolution catalytic activity and stability.
[0007] In order to achieve the above object, the present invention provides a method for preparing a W x N y / Fe3Ni@C self-supporting catalyst, comprising the following steps:
[0008] S1. Cut, ultrasonically clean and dry the carbon paper to obtain pretreated carbon paper;
[0009] S2. Disperse dopamine hydrochloride in Tris-HCl buffer solution, and immerse the pretreated carbon paper therein. After oil bath heating reaction, obtain carbon paper wrapped with polydopamine, i.e., PDA@CP;
[0010] S3. Dissolve ferric nitrate nonahydrate and nickel chloride hexahydrate in a mixed solution in turn to obtain solution A; dissolve phosphotungstic acid and terephthalic acid in the same mixed solution to obtain solution B; fully mix solution A and solution B and place them in a reaction kettle with PDA@CP for hydrothermal reaction to obtain PTA / FeNi-MOF@PDA@CP; wherein, the mixed solution is composed of DMF: ethanol: deionized water, and the volume ratio of DMF, ethanol and deionized water is 10:2:1;
[0011] S4. Calcinate PTA / FeNi-MOF@PDA@CP in an inert atmosphere and naturally cool it to room temperature to obtain W x N y / Fe3Ni@C self-supporting catalyst.
[0012] According to one aspect of the present invention, in step S2, the temperature of the oil bath heating reaction is 60-70 °C, and the time is 12-24 h.
[0013] According to one aspect of the present invention, in step S3, the molar ratio of ferric nitrate nonahydrate to nickel chloride hexahydrate is 1:1-3; the total mass ratio of ferric nitrate nonahydrate and nickel chloride hexahydrate to the mass of the mixed solution is 1:40; the mass ratio of phosphotungstic acid to terephthalic acid is 1-3:2.
[0014] According to one aspect of the present invention, in step S3, the temperature of the hydrothermal reaction is 100 - 180 °C, and the time is 10 - 14 h.
[0015] According to one aspect of the present invention, in step S4, the inert atmosphere is Ar.
[0016] According to one aspect of the present invention, in step S4, the calcination is carried out in a tubular furnace, and the heating rate is 3 - 5 °C / min; the temperature of the calcination is 300 - 700 °C, and the time is 2 - 3 h.
[0017] According to one aspect of the present invention, the reaction kettle is a stainless - steel reaction kettle with a polytetrafluoroethylene lining.
[0018] Based on the same inventive concept, the present invention also provides a W x N y / Fe3Ni@C self - supported catalyst, which is prepared by the preparation method described in any one of the above.
[0019] Based on the same inventive concept, the present invention also provides the above - mentioned W x N y The application of the / Fe3Ni@C self - supported catalyst in the oxygen evolution reaction of water electrolysis for hydrogen production.
[0020] The beneficial effects of the present invention:
[0021] (1) The self - supported catalyst prepared by the present invention using carbon paper wrapped with polydopamine as the substrate avoids the problem that powder materials are easily detached under high current density. In addition, the polydopamine wrapping can make the carbon paper hydrophilic, reduce the surface energy of the carbon paper, provide an amino environment for the subsequent material growth, and the nitrogen - carbon structure formed after the high - temperature calcination of polydopamine can improve the conductivity of the catalytic material.
[0022] (2) Compared with the existing use of nickel foam as the substrate, the carbon paper used in the present application has the advantages of uniform structure, corrosion resistance, good conductivity, and stable properties. Therefore, the carbon paper is easy to be modified and can be used as a catalyst substrate.
[0023] (3) The present invention utilizes the special reaction of polydopamine and phosphotungstate (the high water absorption and hydrogen - bond interaction of phosphotungstic acid and polydopamine), incorporates phosphotungstic acid as the tungsten source into the nickel - iron MOF nanomaterial, and the prepared precursor material presents a regular hedgehog - like nanomorphology. The hedgehog - like nanomorphology has a large specific surface area, extremely high chemical activity and structural stability, and the composite material obtained after calcination has excellent conductivity, oxygen evolution catalytic activity and stability.
[0024] (4) Compared with the powder - shaped catalyst, the W x N yThe W / Ni₃Fe@C self-supported catalyst has stronger mechanical strength and stability, and can well maintain the activity of the catalytic material.
[0025] (5) After introducing a high-valent hetero-metal into the nickel-iron-based MOFs in the present invention, the electron cloud density around the original metals (nickel and iron) is changed. The introduction of high-valent tungsten can act as an electron acceptor, attracting electrons from nickel and iron atoms, causing changes in the electronic structures of nickel and iron. This change can accelerate the charge transfer process. Description of the Drawings
[0026] Figure 1 Material W prepared in Example 1 and Comparative Example 1 of the present invention 2.56 XRD pattern of N₃ / Fe₃Ni;
[0027] Figure 2 SEM images of different magnifications of the material prepared in Comparative Example 2 of the present invention; among them, (a) is the SEM image magnified 2000 times; (b) is the SEM image magnified 5000 times;
[0028] Figure 3 SEM image of the material prepared in Example 1 of the present invention;
[0029] Figure 4 LSV curves of OER of the materials prepared in Examples 1-3 and Comparative Example 1 of the present invention in an oxygen-saturated 1 M KOH electrolyte. Detailed Embodiments
[0030] To make the present invention easier to understand, the present invention will be further described below in conjunction with specific embodiments. It should be understood that these embodiments are only used to illustrate the present invention and not to limit the scope of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts fall within the scope of protection of the present invention. Unless otherwise defined, the professional terms used hereinafter have the same meaning as understood by those of ordinary skill in the art; unless otherwise specified, the raw materials and reagents involved herein can be purchased from the market or prepared by known methods.
[0031] It should be noted that PTA in this application is phosphotungstic acid, FeNi-MOF in this application is nickel-iron-based MOFs; PDA in this application is polydopamine.
[0032] To solve the problems mentioned in the background art, the inventors of this application provide a x W y preparation method of N / W / Ni₃Fe@C self-supported catalyst, including the following steps:
[0033] S1. Cut, ultrasonically clean, and dry the carbon paper to obtain the pretreated carbon paper;
[0034] S2. Disperse dopamine hydrochloride in a Tris-HCl buffer solution, immerse the pretreated carbon paper in it, and after oil bath heating reaction, obtain the carbon paper wrapped with polydopamine, namely PDA@CP;
[0035] S3. Dissolve ferric nitrate nonahydrate and nickel chloride hexahydrate in a mixed solution in turn to obtain solution A; dissolve phosphotungstic acid and terephthalic acid in the same mixed solution to obtain solution B; fully mix solution A and solution B and place PDA@CP in a reaction kettle and carry out hydrothermal reaction to obtain PTA / FeNi-MOF@PDA@CP; wherein, the mixed solution is composed of DMF:ethanol:deionized water, and the volume ratio of DMF, ethanol and deionized water is 10:2:1;
[0036] S4. Calcinate PTA / FeNi-MOF@PDA@CP in an inert atmosphere and naturally cool it to room temperature to obtain the W x N y / Fe3Ni@C self-supporting catalyst.
[0037] In one embodiment, in step S2, the mass ratio of the dopamine hydrochloride to the Tris-HCl buffer solution is 0.02 - 0.05:50.
[0038] It should be noted that the above Tris-HCl buffer solution is prepared by taking 0.05 grams of dopamine hydrochloride and 50 milliliters of Tris solution; the pH value of the Tris-HCl buffer solution is 7 - 9.
[0039] In one embodiment, in step S2, the temperature of the oil bath heating reaction is 40 - 90 °C, and the time is 12 - 24 h.
[0040] In one embodiment, in step S3, the molar ratio of the ferric nitrate nonahydrate to the nickel chloride hexahydrate is 1:1 - 3; the total mass of the ferric nitrate nonahydrate and the nickel chloride hexahydrate and the mass of the mixed solution is 1:40; the mass ratio of the phosphotungstic acid to the terephthalic acid is 1 - 3:2.
[0041] In one embodiment, in step S3, the temperature of the hydrothermal reaction is 100 - 180 °C, and the time is 10 - 14 h.
[0042] In one embodiment, in step S4, the inert atmosphere is Ar.
[0043] In one embodiment, in step S4, the calcination is carried out in a tube furnace with a heating rate of 3 to 5°C / min; the calcination temperature is 500 to 700°C and the calcination time is 2 to 3h.
[0044] In one embodiment, the reactor is a stainless steel reactor with a polytetrafluoroethylene lining.
[0045] The following is further described in conjunction with specific embodiments and comparative examples.
[0046] Example 1
[0047] A W 2.56 The preparation method of N3 / Fe3Ni@C self-supporting catalyst comprises the following steps:
[0048] (1) Pretreatment of carbon paper: The carbon paper was cut into a 1 cm*2 cm rectangle and ultrasonically treated with acetone, anhydrous ethanol and deionized water for 15 minutes in sequence. After the treatment, the carbon paper was dried in an oven at 60°C for later use.
[0049] (2) Thermal polymerization reaction: 0.05 g of dopamine hydrochloride (PDA) was dispersed in 50 mL of Tris-HCl buffer solution (prepared with 0.05 g of dopamine hydrochloride and 50 mL of Tris solution), and then the pretreated carbon paper was added to immerse the carbon paper in the solution and stirred in a 60°C oil bath for 24 hours. After the reaction, the carbon paper wrapped with polydopamine (PDA@CP) was taken out, rinsed with deionized water for 3-5 times, and placed in an oven to dry at 60°C for 12 hours.
[0050] (3) Hydrothermal reaction: 1 mmol of ferric nitrate nonahydrate (Fe(NO3)3·9H2O) and 2 mmol of nickel chloride hexahydrate (NiCl2·6H2O) were dissolved in 26 mL of a mixed solution (DMF: ethanol: deionized water = 10:2:1) and marked as solution A. 0.5 g of phosphotungstic acid and 3 mmol of terephthalic acid were dissolved in the same mixed solution and marked as solution B. After the A and B solutions were fully mixed, they were placed in a stainless steel reactor with polydopamine-wrapped carbon paper (PDA@CP) and subjected to hydrothermal reaction at 180°C for 12 hours. After the hydrothermal reaction was completed and the reactor was cooled naturally, the carbon paper (PTA / FeNi-MOF@PDA@CP) was taken out and washed with ethanol and deionized water for 3-5 times, respectively, and dried at 60°C for 12 hours.
[0051] (4) Calcination reaction: PTA / FeNi-MOF@PDA@CP was placed in a porcelain boat, placed in the center of a tube furnace, and calcined at 700°C in an Ar atmosphere at a heating rate of 5°C / min for two hours. The mixture was naturally cooled to room temperature to obtain W. 2.56N3 / Fe3Ni@C self-supporting catalyst.
[0052] Example 2
[0053] The difference between this example and Example 1 is that the addition amount of phosphotungstic acid in step (3) is 0.25 g, and other steps and parameters are the same as those in Example 1.
[0054] Example 3
[0055] The difference between this example and Example 1 is that the addition amount of phosphotungstic acid in step (3) is 0.75 g, and other steps and parameters are the same as those in Example 1.
[0056] Comparative Example 1
[0057] The difference between this comparative example and Example 1 is that no phosphotungstic acid is added in step (3), and other steps and parameters are the same as those in Example 1.
[0058] Comparative Example 2
[0059] The difference between this comparative example and Example 1 is that the calcination treatment in step (4) is not carried out, and other steps and parameters are the same as those in Example 1.
[0060] Performance detection and result analysis:
[0061] The materials prepared in Example 1 and Comparative Example 1 were analyzed by X-ray diffraction (XRD), and the results are as Figure 1 shown. The materials prepared in Example 1 and Comparative Example 2 were analyzed by scanning electron microscopy (SEM), and the results are as Figure 2 and Figure 3 shown. The materials prepared in Examples 1-3 and Comparative Example 1 were analyzed by linear sweep voltammetry (LSV) of oxygen evolution reaction (OER) in an oxygen-saturated 1 M KOH electrolyte, and the results are as Figure 4 shown. It can be seen from Figure 1 that tungsten was successfully incorporated into the nickel-iron MOF material. It can be seen from Figure 2 and Figure 3 that the precursor material is in the shape of regular Hericium erinaceus, with extremely high chemical activity and structural stability, and the structure of the calcined material is well maintained. It can be seen from Figure 4 that the W x N y / Fe3Ni@C self-supporting catalyst (where 1 < x < 4, 1 < y < 4) of this application has good electrocatalytic OER performance and stability, and the overpotential at a current density of 10 mA / cm 2 is only 277 mV.
[0062] As described above, it is only the specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or substitutions that can be easily thought of by those skilled in the art within the technical scope disclosed by the present invention should be covered within the protection scope of the present invention. Therefore, the protection scope of the present invention shall be subject to the protection scope of the claims described above.
Claims
1. A W x N y A method for preparing a / Fe3Ni@C self-supporting catalyst, characterized in that: The following steps are involved: S1, cutting, ultrasonicating and drying the carbon paper to obtain pretreated carbon paper; S2, dispersing dopamine hydrochloride in a Tris-HCl buffer solution, and immersing the pretreated carbon paper therein, and after heating reaction, obtaining a carbon paper wrapped with polydopamine, namely PDA@CP; S3, dissolving ferric nitrate nonahydrate and nickel chloride hexahydrate in a mixed solution in sequence to obtain solution A; dissolving phosphotungstic acid and terephthalic acid in the same mixed solution to obtain solution B; fully mixing solution A and solution B and placing them in a reactor with PDA@CP for hydrothermal reaction to obtain PTA / FeNi-MOF@PDA@CP; wherein the mixed solution consists of DMF: ethanol: deionized water; the volume ratio of DMF, ethanol and deionized water is 10:2:1; S4, calcining PTA / FeNi-MOF@PDA@CP in an inert atmosphere and naturally cooling it to room temperature to obtain W x N y / Fe3Ni@C self-supporting catalyst; wherein 1<x<4, 1<y<4.
2. The W according to claim 1 x N y A method for preparing a / Fe3Ni@C self-supporting catalyst, characterized in that: In step S2, the heating reaction is carried out at a temperature of 40 to 100°C and for a time of 12 to 24 hours.
3. The W according to claim 1 x N y A method for preparing a / Fe3Ni@C self-supporting catalyst, characterized in that: In step S3, the molar ratio of the ferric nitrate nonahydrate to the nickel chloride hexahydrate is 1:1-3; the mass ratio of the total mass of the ferric nitrate nonahydrate and the nickel chloride hexahydrate to the mixed solution is 1:
50.
4. The W according to claim 1 x N y A method for preparing a / Fe3Ni@C self-supporting catalyst, characterized in that: In step S3, the mass ratio of the phosphotungstic acid to terephthalic acid is 1 to 3:
2.
5. The W according to claim 1 x N y A method for preparing a / Fe3Ni@C self-supporting catalyst, characterized in that: In step S3, the temperature of the hydrothermal reaction is 100-180° C., and the time is 10-14 hours.
6. The W according to claim 1 x N y A method for preparing a / Fe3Ni@C self-supporting catalyst, characterized in that: In step S4, the inert atmosphere is Ar.
7. The W according to claim 1 x N y A method for preparing a / Fe3Ni@C self-supporting catalyst, characterized in that: In step S4, the calcination is carried out in a tubular furnace with a heating rate of 3 to 5°C / min; the calcination temperature is 300 to 700°C and the calcination time is 2 to 3h.
8. The W according to claim 1 x N y A method for preparing a / Fe3Ni@C self-supporting catalyst, characterized in that: The reactor is a stainless steel reactor with a polytetrafluoroethylene lining.
9. A W x N y / Fe3Ni@C self-supporting catalyst, characterized in that The invention is prepared by the preparation method according to any one of claims 1 to 8.
10. The W according to claim 9 x N y Application of / Fe3Ni@C self-supporting catalyst in oxygen evolution reaction in hydrogen production by water electrolysis.