Lattice-matched mof / l dh self-supporting electrocatalyst and preparation method and application thereof
By constructing a MOF/LDH self-supporting electrocatalyst through a lattice-matched growth strategy, the problems of loose interfacial bonding and poor stability between MOFs and LDHs were solved, achieving high efficiency and long-term stability in oxygen evolution reaction catalysis.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- JIANGXI NORMAL UNIV
- Filing Date
- 2026-03-17
- Publication Date
- 2026-05-29
AI Technical Summary
Existing MOF materials suffer from insufficient active sites, low conductivity, and poor stability. LDHs have poor conductivity and are prone to accumulation. MOF/LDH composite materials have loose interfacial bonding and are prone to detachment, which limits their catalytic performance.
Using iron-based MOF as an internal template, a self-supporting composite electrocatalyst with strong interfacial coupling was constructed by achieving lattice-matched growth of MOF and LDH through a solvothermal reaction that controlled the amount of urea and the ratio of nickel/iron metal.
In 1.0 M KOH solution, the overpotential is as low as 240 mV at a current density of 10 mA cm⁻², and the Tafel slope is 47.4 mV dec⁻¹. The catalytic performance is significantly better than that of single-component MOF, LDH and noble metal RuO₂, and the long-term stability is excellent.
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Figure CN122105512A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of electrocatalysis technology, specifically to lattice-matched MOF / LDH self-supporting electrocatalysts, their preparation methods, and applications. Background Technology
[0002] With the gradual depletion of traditional fossil fuels and the increasing prominence of environmental pollution problems, the design and development of sustainable energy conversion and storage devices has become an urgent need for society today. However, the oxygen evolution reaction (OER), as one of the core reactions in new clean energy conversion and storage devices such as water splitting, metal-air batteries, and fuel cells, involves a four-electron coupled proton transfer process, resulting in sluggish reaction kinetics that severely restricts the improvement of reaction efficiency. The scarcity, high cost, and low stability of existing precious metal catalysts (such as IrO2 and RuO2) further limit their large-scale application.
[0003] Metal-organic frameworks (MOFs) are considered ideal platforms for OER electrocatalysts due to their high specific surface area, abundant active sites, and tunable structures. However, MOF materials generally suffer from insufficient active sites, low conductivity, and poor stability, which greatly restricts their practical application in industrial production. Therefore, developing MOF-based electrocatalytic materials with both high catalytic activity and high stability has become a research hotspot in the field of catalysis. Layered hydrogen hydroxides (LDHs) possess a regular two-dimensional structure, excellent ion exchange capacity, and good alkali resistance. Combining nano-MOFs with LDHs to construct composite materials with novel interface effects and electronic structures can effectively suppress the aggregation and accumulation of LDHs with nano-MOFs, while LDHs can stabilize the framework structure of MOFs, thereby promoting full contact between the composite material and the electrolyte, significantly accelerating the ion transport rate and shortening the ion diffusion distance. However, due to the differences in interfacial energy and nucleation kinetics between MOFs and LDHs, such composite systems still face many challenges in terms of interfacial interactions: the interfacial bonding is not tight and easily detached, the stability is poor, and the mechanism of action is not yet clear. Therefore, it is urgent to develop a simple and efficient MOFs / LDH composite catalyst with a special heterostructure to make up for the shortcomings of existing catalytic materials and achieve a dual improvement in interfacial regulation and electrocatalytic performance.
[0004] In summary, existing MOF materials generally suffer from insufficient active sites, low conductivity, and poor stability; LDHs, on the other hand, are limited in their applications due to poor conductivity and easy accumulation. While constructing composite materials with novel interfacial effects and electronic structures by combining nano-MOFs with LDHs can leverage the advantages of each component and overcome the defects of a single component, current preparation methods mostly rely on physical mixing or simple co-precipitation, resulting in loose interfacial bonding and insufficient exposure of active sites, making it difficult to achieve efficient electron and ion transport. Summary of the Invention
[0005] In view of this, to address the technical problems of insufficient exposure of active sites, low catalytic activity, poor stability, and limited catalytic performance due to the loose interfacial bonding and easy detachment of MOF / LDH composite systems in existing electrocatalysts for oxygen evolution reaction, this invention provides a lattice-matched MOF / LDH self-supporting electrocatalyst, its preparation method, and its application. Using iron-based MOF as an internal template, the solvothermal reaction conditions of urea dosage and nickel / iron metal ratio are controlled to achieve lattice-matched growth of MOF and LDH, constructing a self-supporting composite electrocatalyst with strong interfacial coupling. This catalyst optimizes the adsorption energy of active sites through the interfacial electron rearrangement effect induced by lattice matching, achieving an adsorption energy of 10 mA cm⁻¹ in 1.0 M KOH solution. -2 With an overpotential as low as 240 mV at current density, it combines high oxygen evolution activity with excellent long-term stability, and its performance is significantly better than that of single-component MOF, LDHs and noble metal RuO2 comparative catalysts.
[0006] To achieve the above objectives, the present invention provides the following technical solution: In a first aspect, the present invention provides a method for preparing a lattice-matched MOF / LDH self-supporting electrocatalyst, comprising the following steps: Step (1), Treatment of activated substrate: Hydrophilic activation of carbon fiber paper substrate to obtain activated substrate; Step (2), Preparation of iron-based MOF self-supporting material: Iron salt and organic ligand are grown on the activated substrate obtained in step (1) under solvothermal reaction conditions to form Fe-MOF / CFP self-supporting material; Step (3) Lattice-matched growth of LDH: The Fe-MOF / CFP self-supporting material obtained in step (2) is placed in a solvent system containing nickel salt and urea. The LDH and MOF are grown in a lattice-matched manner through a solvothermal reaction. After cooling, washing and drying, the lattice-matched MOF / LDH self-supporting material is obtained.
[0007] Secondly, the present invention provides a lattice-matched MOF / LDH self-supporting electrocatalyst, which is prepared by the above-described preparation method.
[0008] Thirdly, the present invention provides the application of the above-mentioned lattice-matched MOF / LDH self-supporting electrocatalyst for oxygen evolution reaction in the electrocatalytic oxygen evolution reaction.
[0009] This invention uses iron-based MOFs as internal templates and achieves lattice-matched growth of MOFs and LDHs by controlling the solvothermal reaction conditions of the metal source, urea, and organic ligands, thus constructing a self-supporting composite electrocatalyst structure with strong interfacial coupling. Compared with existing technologies, it has the following advantages: Synergistic enhancement of interface structure: A self-supporting heterojunction of MOF / LDH is constructed by using a lattice-matched growth strategy to achieve strong interfacial coupling between MOF and LDH. This avoids LDH agglomeration and accumulation, stabilizes the MOF framework structure, promotes full contact of electrolyte and rapid ion transport, and solves the problems of loose interfacial bonding and insufficient exposure of active sites in existing composite systems.
[0010] Significantly enhanced catalytic activity: Lattice-matched interfacial electronic rearrangement effectively optimizes the electronic environment and adsorption energy of the metal active sites, reducing the oxygen evolution reaction energy barrier. In 1.0 M KOH solution, 10 mA cm⁻¹ -2 The overpotential at current density is as low as 240 mV, and the Tafel slope is 47.4 mV dec. -1 Its catalytic performance is far superior to that of single-component MIL-88C, Ni-LDH and noble metal RuO2 catalysts.
[0011] Excellent long-term stability: The self-supporting structure requires no additional binder, and the catalyst is firmly bonded to the carbon fiber paper substrate, enabling long-term stable cyclic use and solving the technical problems of easy detachment and poor stability of existing catalysts.
[0012] The preparation process is green and controllable: it is prepared by solvothermal method, the reaction conditions are mild, the raw materials are widely available and low cost, the preparation process does not require complicated equipment, and it is easy to scale up industrial production. Attached Figure Description
[0013] Figure 1 The X-ray diffraction (XRD) patterns of the products obtained in Example 1 and Comparative Example 1 of this invention are shown. Figure 2 The image shows the XRD pattern of the product obtained in Comparative Example 2 of this invention. Figure 3 The XRD patterns are of the products obtained in Examples 2 and 3 of this invention. Figure 4 This is a scanning electron microscope (SEM) image of Embodiment 1 of the present invention; Figure 5 This is a SEM image of Comparative Example 1 of the present invention; Figure 6 This is a SEM image of Comparative Example 2 of the present invention; Figure 7 This is a transmission electron microscope (TEM) image of Embodiment 1 of the present invention; Figure 8 The linear sweep voltammetry (LSV) diagrams for Embodiment 1, Comparative Example 1, Comparative Example 2, and Comparative Example 3 of the present invention are shown. Figure 9 The images show the Tafel slopes of Embodiment 1, Comparative Example 1, Comparative Example 2, and Comparative Example 3 of the present invention. Detailed Implementation
[0014] This invention provides a method for preparing a lattice-matched MOF / LDH self-supporting electrocatalyst, comprising the following steps: Step (1), Treatment of the activated substrate: The carbon fiber paper substrate is hydrophilically activated to obtain an activated substrate. In this step (1), the substrate activation treatment is carried out by reacting concentrated nitric acid at 100~150 ℃ for 2~10 hours. Specifically: Cut carbon fiber paper (CFP) into 1 cm × 3 cm pieces and place them in a reaction vessel containing a certain amount of concentrated nitric acid. Set the temperature to 100-150°C. o C. Keep it for several hours (e.g., 2 to 10 hours), and remove it after it has cooled to room temperature. Wash it and use it for later use.
[0015] Step (2), Preparation of iron-based MOF self-supporting material: Iron salt and organic ligand are grown on the activated substrate obtained in step (1) under solvothermal reaction conditions to form Fe-MOF / CFP self-supporting material. In this step (2), the iron salt is selected from at least one of ferric nitrate nonahydrate, ferric chloride, and ferric sulfate, and the organic ligand is 2,6-naphthalenedicarboxylic acid. The molar ratio of organic ligand to iron salt is 1:1. The solvothermal reaction temperature is 100~150 ℃, and the reaction time is 12~24 hours. Specifically: A certain amount of iron salt and 2,6-naphthalenedicarboxylic acid ligand are weighed and dissolved in N,N-dimethylformamide solvent. A certain amount of glacial acetic acid is added, and the mixture is stirred for a period of time to form a homogeneous solution. The CFP treated in step (1) is then added, and the mixture is kept at a temperature of 100~150 °C for a period of time. After cooling, the mixture is washed and dried to obtain the Fe-MOF / CFP self-supporting material. The stirring time is preferably 10~30 minutes, the drying temperature is preferably 30~60 °C, and the drying time is preferably 10~14 hours.
[0016] Step (3), LDH growth by lattice matching: The Fe-MOF / CFP self-supporting material obtained in step (2) is placed in a solvent system containing nickel salt and urea. LDH and MOF are grown by lattice matching through a solvothermal reaction. After cooling, washing and drying, lattice-matched MOF / LDH self-supporting material is obtained. In this step (3), the mass ratio of iron-based MOF to urea in the synthesis of Fe-MOF / CFP self-supporting material is 1~4. A product with better electrocatalytic oxygen evolution performance can be obtained. The solvothermal reaction temperature is 80~100℃, and the reaction time is 5~10 hours, preferably 3~8 hours. Since the ratio of iron salt to nickel salt will affect the morphology and size of the lattice-matched MOF / LDH self-supporting material, it will ultimately affect the quality of the electrocatalytic oxygen evolution performance. The mass ratio of MOF to added nickel salt in the lattice-matched MOF / LDH self-supporting material is 1:(8~15). Better electrocatalytic performance can be obtained. Nickel salt is preferably nickel nitrate hexahydrate. The drying temperature is preferably 30~60℃; the drying time is preferably 10~14 hours.
[0017] This invention provides a lattice-matched MOF / LDH self-supporting electrocatalyst, prepared by the method described above. Using an iron-based MOF as an internal template, a strongly interfacially coupled self-supporting heterostructure is formed by growing a two-dimensional LDH with the MOF through lattice matching.
[0018] This invention provides the application of the lattice-matched MOF / LDH self-supporting electrocatalyst described above for the oxygen evolution reaction (OER) in the electrocatalytic OER. This catalyst can optimize the electronic environment of the active sites, lower the OER energy barrier, and achieve an efficiency of 10 mA cm⁻¹ in 1.0 MKOH solution. -2 Overpotential at current density ≤ 256 mV, Tafel slope ≤ 55.7 mV dec -1 .
[0019] The technical solution of the present invention will be clearly and thoroughly described below with reference to specific embodiments.
[0020] Example 1 A lattice-matched MOF / LDH self-supporting electrocatalyst (LM-MOF / LDH) and its preparation method, comprising the following steps: (1) Treatment of activated substrate: Cut carbon fiber paper (CFP) into small pieces of 1 cm × 3 cm, place them in a reaction vessel containing a certain amount of concentrated nitric acid, and set the temperature to 120°C. o C, keep for 4 hours, and remove after cooling to room temperature, wash and use for later use.
[0021] (2) Preparation of MOF: Weigh 0.23 mmol of ferric nitrate nonahydrate and 2,6-naphthalenedicarboxylic acid ligand, dissolve in 10 mL of N,N-dimethylformamide solvent, add 50 μL of glacial acetic acid, stir for 0.5 hours to form a homogeneous solution, add CFP treated in step (1), and keep at 100 °C for 24 hours; after cooling and washing and drying, Fe-MOF / CFP self-supporting material is obtained.
[0022] (3) The Fe-MOF / CFP self-supporting material obtained in step (2) is added to 10 mL of ethanol solvent containing 150 mg nickel nitrate hexahydrate and 40 mg urea, and kept at 90 °C for 5 hours. After cooling, it is washed and dried to obtain lattice-matched MOF / LDH self-supporting material.
[0023] Example 2 A lattice-matched MOF / LDH self-supporting electrocatalyst and its preparation method, comprising the following steps: (1) Treatment of activated substrate: Cut carbon fiber paper (CFP) into small pieces of 1 cm × 3 cm, place them in a reaction vessel containing a certain amount of concentrated nitric acid, and set the temperature to 120°C. o C, keep for 4 hours, and remove after cooling to room temperature, wash and use for later use.
[0024] (2) Preparation of MOF: Weigh 0.23 mmol of ferric nitrate nonahydrate and 2,6-naphthalenedicarboxylic acid ligand, dissolve in 10 mL of N,N-dimethylformamide solvent, add 50 μL of glacial acetic acid, stir for 0.5 hours to form a homogeneous solution, add the CFP treated in step (1), and keep at 100℃ for 24 hours; after cooling and washing and drying, Fe-MOF / CFP self-supporting material is obtained.
[0025] (3) The Fe-MOF / CFP self-supporting material obtained in step (2) is added to 10 mL of ethanol solvent containing 150 mg nickel nitrate hexahydrate and 15 mg urea, and kept at 90 °C for 5 hours. After cooling, it is washed and dried to obtain lattice-matched MOF / LDH self-supporting material.
[0026] Example 3 A lattice-matched MOF / LDH self-supporting electrocatalyst and its preparation method, comprising the following steps: (1) Treatment of activated substrate: Cut carbon fiber paper (CFP) into small pieces of 1 cm × 3 cm, place them in a reaction vessel containing a certain amount of concentrated nitric acid, and set the temperature to 120°C. o C, keep for 4 hours, and remove after cooling to room temperature, wash and use for later use.
[0027] (2) Preparation of MOF: Weigh 0.23 mmol of ferric nitrate nonahydrate and 2,6-naphthalenedicarboxylic acid ligand, dissolve in 10 mL of N,N-dimethylformamide solvent, add 50 μL of glacial acetic acid, stir for 0.5 hours to form a homogeneous solution, add CFP treated in step (1), and keep at 100 °C for 24 hours; after cooling and washing and drying, Fe-MOF / CFP self-supporting material is obtained.
[0028] (3) The Fe-MOF / CFP self-supporting material obtained in step (2) is added to 10 mL of ethanol solvent containing 150 mg nickel nitrate hexahydrate and 20 mg urea, and kept at 90 °C for 5 hours. After cooling, it is washed and dried to obtain lattice-matched MOF / LDH self-supporting material.
[0029] Example 4 A lattice-matched MOF / LDH self-supporting electrocatalyst and its preparation method, comprising the following steps: (1) Treatment of activated substrate: Cut carbon fiber paper (CFP) into small pieces of 1 cm × 3 cm, place them in a reaction vessel containing a certain amount of concentrated nitric acid, and set the temperature to 120°C. o C, keep for 4 hours, and remove after cooling to room temperature, wash and use for later use.
[0030] (2) Preparation of MOF: Weigh 0.23 mmol of ferric nitrate nonahydrate and 2,6-naphthalenedicarboxylic acid ligand, dissolve in 10 mL of N,N-dimethylformamide solvent, add 50 μL of glacial acetic acid, stir for 0.5 hours to form a homogeneous solution, add CFP treated in step (1), and keep at 100 °C for 24 hours; after cooling and washing and drying, Fe-MOF / CFP self-supporting material is obtained.
[0031] (3) The Fe-MOF / CFP self-supporting material obtained in step (2) is added to 10 mL of ethanol solvent containing 150 mg nickel nitrate hexahydrate and 60 mg urea, and kept at 90°C for 5 hours. After cooling, it is washed and dried to obtain lattice-matched MOF / LDH self-supporting material.
[0032] Example 5 A lattice-matched MOF / LDH self-supporting electrocatalyst and its preparation method, comprising the following steps: (1) Treatment of activated substrate: Cut carbon fiber paper (CFP) into small pieces of 1 cm × 3 cm, place them in a reaction vessel containing a certain amount of concentrated nitric acid, and set the temperature to 120°C. o C, keep for 4 hours, and remove after cooling to room temperature, wash and use for later use.
[0033] (2) Preparation of MOF: Weigh 0.23 mmol of ferric nitrate nonahydrate and 2,6-naphthalenedicarboxylic acid ligand, dissolve in 10 mL of N,N-dimethylformamide solvent, add 50 μL of glacial acetic acid, stir for 0.5 hours to form a homogeneous solution, add CFP treated in step (1), and keep at 100 °C for 24 hours; after cooling and washing and drying, Fe-MOF / CFP self-supporting material is obtained.
[0034] (3) The Fe-MOF / CFP self-supporting material obtained in step (2) is added to 10 mL of ethanol solvent containing 120 mg nickel nitrate hexahydrate and 40 mg urea, and kept at 90°C for 5 hours. After cooling, it is washed and dried to obtain lattice-matched MOF / LDH self-supporting material.
[0035] Example 6 A lattice-matched MOF / LDH self-supporting electrocatalyst and its preparation method, comprising the following steps: (1) Treatment of activated substrate: Cut carbon fiber paper (CFP) into small pieces of 1 cm × 3 cm, place them in a reaction vessel containing a certain amount of concentrated nitric acid, and set the temperature to 120°C. o C, keep for 4 hours, and remove after cooling to room temperature, wash and use for later use.
[0036] (2) Preparation of MOF: Weigh 0.23 mmol of ferric nitrate nonahydrate and 2,6-naphthalenedicarboxylic acid ligand, dissolve in 10 mL of N,N-dimethylformamide solvent, add 50 μL of glacial acetic acid, stir for 0.5 hours to form a homogeneous solution, add CFP treated in step (1), and keep at 100 °C for 24 hours; after cooling and washing and drying, Fe-MOF / CFP self-supporting material is obtained.
[0037] (3) The Fe-MOF / CFP self-supporting material obtained in step (2) is added to 10 mL of ethanol solvent containing 225 mg nickel nitrate hexahydrate and 40 mg urea, and kept at 90°C for 5 hours. After cooling, it is washed and dried to obtain lattice-matched MOF / LDH self-supporting material.
[0038] Comparative Example 1 The preparation of Fe-MOF nanorod electrocatalysts includes the following steps: (1) Weigh 0.23 mmol of ferric nitrate nonahydrate and 0.23 mmol of 2,6-naphthalenedicarboxylic acid (NDA) into a 25 mL beaker, and add 10 mL of N,N-dimethylformamide (DMF) to dissolve by sonication to form a clear solution A. (2) Add 50 μL of glacial acetic acid to the mixed solution A obtained in step (1) and stir for 0.5 hours. Then transfer the solution to a 25 mL stainless steel autoclave lined with polytetrafluoroethylene and keep it at 100 °C for 24 hours. (3) After the temperature of the reactor drops to room temperature, the precipitate is taken out and washed 2-3 times by centrifugation with DMF and ethanol, and then vacuum dried at 30°C for 12 hours. The Fe-MOF nanorod electrocatalyst is then collected.
[0039] Comparative Example 2 The method for preparing NO3-Ni LDH electrocatalyst includes the following steps: (1) Weigh 150 mg of nickel nitrate hexahydrate and 40 mg of urea and dissolve them in 10 mL of ethanol solution. Stir for 0.5 hours to obtain a clear solution A. (2) Transfer the solution A obtained in step (1) into a 25 mL sealed Shrek tube and in an oil bath at 90 °C for 5 hours. After cooling to room temperature, wash the product several times with ethanol by centrifugation, and then dry it at 60 °C for 10 hours to obtain the NO3-NiLDH electrocatalyst.
[0040] Comparative Example 3 The method for preparing RuO2 electrocatalyst includes the following steps: Weigh 2.5 g of ruthenium chloride hexahydrate and dissolve it in 50 mL of deionized water. Slowly add 20 mL of ammonia solution and stir for 0.5 hours to obtain a mixed solution A containing Ru(OH)3 precipitate. Slowly add 10 mL of 30% H2O2 to the mixed solution A obtained in step (1), stir at room temperature for 2 hours, and centrifuge to collect the black precipitate B. The black precipitate B obtained in step (2) was washed three times with deionized water and once with ethanol, and then vacuum dried at 60°C for 12 hours to obtain RuO2 electrocatalyst.
[0041] Performance testing experiment 1. Structural and morphological testing The structure and microstructure were tested using powder X-ray diffraction, scanning electron microscopy, and transmission electron microscopy. The X-ray diffraction (XRD) patterns of the products prepared in Example 1 and Comparative Examples 1 and 2 are shown below. Figure 1-2 As shown; the XRD patterns of the products obtained in Examples 2 and 3 are shown in the figure. Figure 3 The scanning electron microscope (SEM) image of the product prepared in Example 1 is shown below. Figure 4 SEM images of the products prepared in Comparative Example 1 are shown below. Figure 5 SEM images of the products prepared in Comparative Example 2 are shown below. Figure 6 The transmission electron microscope (TEM) image of the product prepared in Example 1 is shown below. Figure 7The test results above show that: As attached Figure 1 As shown, the diffraction peak positions of Example 1 (lattice-matched MOF / LDH self-supporting material) correspond one-to-one with the characteristic crystal planes of Comparative Example 1 (Fe-MOF) and Comparative Example 2 (NO3-Ni LDH), proving that the present invention successfully prepared a lattice-matched MOF / LDH self-supporting material. Compared with Comparative Example 1 and Comparative Example 2, the diffraction peaks corresponding to the MIL-88C crystal plane in Example 2 are slightly shifted to higher angles, while the diffraction peaks corresponding to the NO3-Ni LDH crystal plane are slightly shifted to lower angles. This means that there is a strong interfacial interaction between MIL-88C and NO3-Ni LDH in the lattice-matched MOF / LDH self-supporting material composite structure. From the appendix... Figure 2 , 3 As can be seen from the data, in Comparative Example 2, without Fe MOF as a template for directional growth, the synthesized material has NO intercalation anion. 3- Ni LDH-NO3, not CO3 2- The intercalated Ni LDH indicates that Fe MOF plays a crucial role in the growth of Ni LDH. Examples 2 and 3 use different urea contents compared to Example 1. As can be seen from the corresponding peak areas, the proportion of Ni LDH in the composite material increases with the increase of urea content.
[0042] As attached Figure 4 As shown in Example 1, the morphology of the prepared sample was observed using SEM. The basic framework of Fe MOF was well maintained, and two-dimensional nanosheets were neatly coated on the Fe MOF surface, demonstrating the successful preparation of the Fe MOF / Ni LDH heterostructure. (See attached...) Figure 5 , 6 As can be seen, Comparative Example 1, like most MILs, exhibits a rod-shaped nanomorphology with a tapered tip, and the particles are relatively uniform in size, with a smooth and flat surface, an average length of about 1.2 μm, and a diameter of about 170 nm. In addition, the Ni LDH-NO3 prepared in Comparative Example 2 without Fe MOF growth template also has a two-dimensional sheet structure.
[0043] like Figure 7 As shown, in the lattice-matched MOF / LDH self-supporting material prepared in Example 1, NO3-Ni LDH nanosheets are completely grown on the entire surface of the Fe MOF precursor, and there is a very clear heterojunction interface between the two. The special heterojunction interface between Fe MOF and NO3-Ni LDH not only promotes the charge transfer capability of the material, but also helps to fully expose the electrocatalytic active sites, thereby improving the electrocatalytic performance.
[0044] 2. OER Performance Test Test method: The electrocatalytic testing of this invention was conducted in a standard three-electrode system, wherein the lattice-matched MOF / LDH self-supporting material served as the working electrode, the Hg / HgO electrode as the reference electrode, and the graphite rod electrode as the counter electrode. At 1 mol L... -1 Linear cyclic voltammetry was performed in KOH solution with a scan voltage range of 0.3–1.2 V and a scan rate of 5 mV / s. -1 All test data were 95% iR compensated. The Tafel slope was plotted from the linear cyclic voltammetry (LSV) curve using the following formula: η = a + b logj, where η is the overpotential (mV) and j is the corresponding current density (mA / cm²). -2 b is the Tafel slope (unit: mV dec) -1 ).
[0045] Test results: Electrocatalytic tests were performed on the catalysts obtained in Examples 1-6 and Comparative Examples 1-3 according to the above method. The results of each catalyst at 10 mA cm⁻¹ were obtained. -2 The overvoltage and Tafel slope results corresponding to the current density are shown in Table 1. The OER polarization curves of the catalysts obtained in Example 2 and Comparative Examples 1, 2, and 3 are attached. Figure 8 As shown in the attached diagram, the Tafel slope is... Figure 9 As shown.
[0046] Table 1 OER Performance Test Results
[0047] As shown in Table 1, compared to Fe MOF, LDH, and RuO2, the lattice-matched MOF / LDH self-supporting material exhibits superior electrocatalytic oxygen evolution activity. This can be attributed to the unique interfacial interaction between MOF and LDH in the lattice-matched MOF / LDH self-supporting material. This interaction helps to regulate the strength of the MO bond and optimize the electronic environment of the metal catalytic active sites, thereby improving OER activity. We believe that by rationally selecting two or more lattice-matched materials to construct heterojunction composite materials, the composite material interface can be precisely designed, which has a very broad prospect for development in electrocatalytic OER and other related fields.
[0048] The above description is merely a preferred embodiment of the present invention. However, the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention should be covered within the scope of protection of the present invention.
Claims
1. A method for preparing a lattice-matched MOF / LDH self-supporting electrocatalyst, characterized in that, Includes the following steps: Step (1), Treatment of activated substrate: Hydrophilic activation of carbon fiber paper substrate to obtain activated substrate; Step (2), Preparation of iron-based MOF self-supporting material: Iron salt and organic ligand are grown on the activated substrate obtained in step (1) under solvothermal reaction conditions to form Fe-MOF / CFP self-supporting material; Step (3) Lattice-matched growth of LDH: The Fe-MOF / CFP self-supporting material obtained in step (2) is placed in a solvent system containing nickel salt and urea. The LDH and MOF are grown in a lattice-matched manner through a solvothermal reaction. After cooling, washing and drying, the lattice-matched MOF / LDH self-supporting material is obtained.
2. The method for preparing a lattice-matched MOF / LDH self-supporting electrocatalyst according to claim 1, characterized in that, In step (1), the substrate activation treatment is carried out by reacting concentrated nitric acid at 100~150 °C for 2~10 hours.
3. The method for preparing a lattice-matched MOF / LDH self-supporting electrocatalyst according to claim 1, characterized in that, In step (2), the molar ratio of the organic ligand to the iron salt is 1:
1.
4. The method for preparing a lattice-matched MOF / LDH self-supporting electrocatalyst according to claim 1, characterized in that, In step (2), the iron salt is selected from at least one of ferric nitrate nonahydrate, ferric chloride, and ferric sulfate, and the organic ligand is 2,6-naphthalenedicarboxylic acid.
5. The method for preparing a lattice-matched MOF / LDH self-supporting electrocatalyst according to claim 1, characterized in that, In step (3), the mass ratio of MOF to added nickel salt in the lattice-matched MOF / LDH self-supporting material is 1:(8~15).
6. The method for preparing a lattice-matched MOF / LDH self-supporting electrocatalyst according to claim 1, characterized in that, In step (3), the mass ratio of iron-based MOF to urea in the synthesis of Fe-MOF / CFP self-supporting materials is 1~4.
7. The method for preparing a lattice-matched MOF / LDH self-supporting electrocatalyst according to claim 1, characterized in that, In step (2), the solvothermal reaction temperature for synthesizing the Fe MOF / CFP self-supporting catalyst is 100~150 ℃, and the reaction time is 12~24 hours.
8. A method for preparing a lattice-matched MOF / LDH self-supporting electrocatalyst according to any one of claims 1-7, characterized in that, In step (3), the solvothermal reaction temperature for synthesizing lattice-matched MOF / LDH is 80~100 ℃, and the reaction time is 3~8 hours.
9. A lattice-matched MOF / LDH self-supporting electrocatalyst, characterized in that, It is prepared by the preparation method according to any one of claims 1-8.
10. The application of the lattice-matched MOF / LDH self-supporting electrocatalyst of claim 9 in the electrocatalytic oxygen evolution reaction.