Two-dimensional medium-entropy metal-organic framework catalyst as well as preparation method and application thereof

Abstract

The invention discloses a two-dimensional medium-entropy metal-organic framework catalyst as well as a preparation method and application thereof. Belongs to the technical field of energy materials. The method comprises the following steps: dissolving Ni salt, Co salt, Fe salt and Mo salt in a mixed solution of DMF, ethanol and water, then adding terephthalic acid and TEA, stirring to obtain a uniform colloidal suspension solution, and carrying out ultrasonic treatment under closed conditions; and centrifugally collecting the product, washing and drying to finally prepare the two-dimensional ME-MOFs catalyst prepared by room-temperature ultrasonic treatment. The catalyst prepared by the invention is low in raw material cost, simple in preparation process and green and environment-friendly in preparation process; the material has a sheet structure, and can be used for electrocatalysis due to the properties of high specific surface area, adjustable structure and the like.

Description

Technical Field

[0001] The present invention belongs to the technical field of energy materials, and particularly relates to a two-dimensional medium entropy metal-organic framework catalyst, a preparation method thereof, and an application thereof. Background Art

[0002] With the rapid development of modern society, the large consumption of fossil energy has become a key concern globally. This not only leads to the exhaustion of energy but also causes serious environmental problems. Therefore, turning to clean and sustainable energy has become an inevitable trend. To address the urgent need for clean and sustainable energy, producing hydrogen and oxygen by electrolyzing water is an effective solution to obtain clean energy. However, the slow kinetics of the oxygen evolution reaction (OER) and hydrogen evolution reaction (HER) seriously hinder the realization of efficient water splitting. Therefore, finding highly active and stable electrocatalysts remains an urgent problem to be solved. Currently, commercially available noble metal-based materials (such as IrO2, RuO2, Pt, etc.) have excellent OER and HER catalytic activities, but their scarcity and high cost seriously impede their practical applications.

[0003] Metal-organic frameworks (MOFs) are a class of novel crystalline microporous materials formed by metal atom nodes and organic ligands with periodic structural units through coordination bonds. They have characteristics such as high specific surface area, adjustable porosity, and functional group diversity, and have attracted wide attention in the field of electrocatalysis. Compared with single-metal MOF materials, medium entropy metal-organic frameworks (ME-MOFs) are usually composed of three to four main metal elements, each of which has different ionic sizes, which may lead to slight lattice disorder. Their customizable composition and adjustable atomic ratio can also optimize the adsorption energy of reactants on the catalyst surface, thereby promoting catalytic activity. In particular, two-dimensional ME-MOFs have a nanosheet configuration, and their highly exposed surface area, abundant adjustable active sites, and excellent mechanical flexibility distinguish them from bulk ME-MOFs and have attracted wide attention. Generally speaking, two-dimensional ME-MOFs are mostly synthesized by methods such as solvothermal and microwave-assisted methods. However, this strategy requires high energy and is prone to agglomeration, which may lead to uneven crystal growth and reduction of active sites. Summary of the Invention

[0004] Aiming at the problem that the synthesis of two-dimensional ME-MOFs by methods such as solvothermal and microwave-assisted methods may lead to uneven crystal growth and reduction of active sites, the present invention discloses a method for preparing a two-dimensional ME-MOFs catalyst by simple room-temperature ultrasonic treatment, which improves the high energy cost and the resulting agglomeration phenomenon in the preparation process.

[0005] To achieve the above object, the present invention provides the following technical solutions: A method for preparing a two-dimensional ME-MOFs catalyst by room-temperature ultrasonic treatment, comprising the following steps: (1) Dissolve Ni salt, Co salt, Fe salt, and Mo salt in a mixed solution of dimethylformamide (DMF), ethanol (C2H5OH), and water (H2O) to obtain a metal salt solution; (2) Add 1,4-benzenedicarboxylic acid (1,4-BDC) to the above solution, stir to dissolve it, and quickly inject triethylamine (TEA) after dissolution, and stir to form a uniform colloidal suspension; (3) Under closed conditions, perform ultrasonic treatment on the colloidal suspension in step (2) to promote the formation of the framework; the product is collected by centrifugation, followed by washing and drying to finally obtain a two-dimensional ME-MOFs catalyst.

[0006] The two-dimensional ME-MOFs material of the present invention is prepared by a simple room-temperature ultrasonic method, using environmentally friendly and low-cost raw materials, with a simple process, easy to operate and control, suitable for continuous large-scale production, and the preparation process is green and environmentally friendly.

[0007] It has been experimentally confirmed that this ME-MOFs material has a flaky structure and can be used for electrocatalysis due to its excellent properties such as high specific surface area and excellent conductivity.

[0008] Further, in step (1), the Ni salt, Co salt, Fe salt, and Mo salt are NiCl2·6H2O, CoCl2·6H2O, FeCl3·6H2O, and MoCl5, respectively; The Ni salt and Co salt are Ni(CH3COO)2·4H2O and Co(CH3COO)2·4H2O or Ni(NO3)2·6H2O and Co(NO3)2·6H2O; the Fe salt is Fe(NO3)3·9H2O.

[0009] The acid radicals of the above metal salts are easily removed, and the desired product is more easily obtained.

[0010] Further, in step (1), the molar ratio of NiCl2·6H2O, CoCl2·6H2O, FeCl3·6H2O, and MoCl5 is (0.7~1.2):(0.7~1.2):(0.7~1.2):(0.7~1.2), preferably 1:1:1:1.

[0011] Further, in step (1), the volume ratio of dimethylformamide (DMF), ethanol (C2H5OH), and water (H2O) is (16~8):1:1.

[0012] Further, the molar ratio of terephthalic acid (1,4-BDC) to metal salt described in step (2) is (1:1) to (1:2).

[0013] The molar ratio of triethylamine to terephthalic acid described in step (2) is (4 - 8):1.

[0014] Further, the stirring time described in step (2) is 5 - 10 min.

[0015] Further, the ultrasonic reaction time described in step (3) is 0.5 - 4 h.

[0016] Another object of the present invention also proposes the application of the two-dimensional ME-MOFs material prepared by the above method in electrocatalysis.

[0017] Under ultrasonic conditions, dissolve it in Nafion solution, and then modify it on a glassy carbon electrode to obtain a glassy carbon electrode modified with the sample.

[0018] The beneficial effects of the present invention are as follows: (1) The two-dimensional ME-MOFs material prepared by the present invention is prepared by simple room-temperature ultrasonic treatment. The raw materials used have low costs, the preparation process is simple, easy to operate and control, suitable for continuous large-scale production, and the preparation process is green and environmentally friendly.

[0019] (2) The catalyst prepared by the preparation method provided by the present invention has a uniform flaky structure, greatly improves the electron transfer process in electrocatalysis, exposes more active sites and accelerates the electrochemical mass transfer rate, and improves the electrocatalytic activity and stability of the catalyst.

[0020] (3) Compare the catalyst prepared by the present invention with commercial RuO2 and Pt / C catalysts in an alkaline medium, see Appendix Figure 4 and Appendix Figure 5 , the OER overpotential of the catalyst prepared by the present invention is even higher than that of commercial RuO2 catalyst compared with commercial RuO2, indicating that the catalyst prepared by the present invention has excellent electrocatalytic activity comparable to RuO2 catalyst in an alkaline medium. The HER performance of the catalyst prepared by the present invention exceeds that of commercial Pt / C at an overpotential of 200 mA, indicating that the catalyst prepared by the present invention has electrocatalytic activity comparable to Pt / C catalyst at a high current density. Description of the Drawings

[0021] Figure 1 XRD pattern of the two-dimensional ME-MOFs catalyst prepared in Example 1; Figure 2 XPS pattern of the two-dimensional ME-MOFs catalyst prepared in Example 1; Figure 3 SEM pattern of the two-dimensional ME-MOFs catalyst prepared in Example 1; Figure 4 Comparison chart of OER curves of the two-dimensional ME-MOFs catalyst prepared in Example 1 and commercial RuO2 catalyst in alkaline medium; Figure 5 Comparison chart of HER curves of the two-dimensional ME-MOFs catalyst prepared in Example 1 and commercial Pt / C catalyst in alkaline medium. Detailed implementation manners

[0022] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments 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. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0023] The two-dimensional ME-MOFs catalyst prepared by room-temperature ultrasonic treatment disclosed in the present invention is applied to oxygen evolution and hydrogen evolution reactions in alkaline or acidic media.

[0024] A preparation method for preparing a two-dimensional ME-MOFs catalyst by room-temperature ultrasonic treatment, the steps are as follows: (1) Dissolve NiCl2·6H2O, CoCl2·6H2O, FeCl3·6H2O and MoCl5 in a mixed solution of dimethylformamide (DMF), ethanol (C2H5OH) and water (H2O) to obtain a metal salt solution; (2) Add 1,4-benzenedicarboxylic acid (1,4-BDC) to the above solution and stir until 1,4-BDC is completely dissolved; quickly inject triethylamine (TEA) and stir for 5-10 min to form a uniform colloidal suspension; (3) Under closed conditions, perform ultrasonic treatment on the colloidal suspension in step (2) to promote the formation of the framework; the product is collected by centrifugation, followed by washing and drying to finally obtain a two-dimensional ME-MOFs catalyst.

[0025] In step (1): The molar ratio of NiCl2·6H2O, CoCl2·6H2O, FeCl3·6H2O and MoCl5 is (0.7-1.2):(0.7-1.2):(0.7-1.2):(0.7-1.2); the volume ratio of DMF, ethanol and water is (16-8):1:1.

[0026] In step (2): The molar ratio of the fed terephthalic acid (1,4-BDC) to the metal salt is (1:1) to (1:2).

[0027] In step (3): The sonication time is 0.5 to 4 h.

[0028] The technical solution of the present invention will be further described below in conjunction with embodiments: Example 1 To prepare a two-dimensional ME-MOFs catalyst with a room temperature sonication time of 1 h, the steps are as follows: (1) Weigh 44.57 mg (0.1875 mmol) of NiCl2·6H2O, 44.61 mg (0.1875 mmol) of CoCl2·6H2O, 50.68 mg (0.1875 mmol) of FeCl3·6H2O, and 51.23 mg (0.1875 mmol) of MoCl5, four metal salts, and dissolve them in a mixed solution of 32 ml of dimethylformamide (DMF), 2 ml of ethanol (C2H5OH), and 2 ml of water (H2O), and stir well to ensure complete dissolution; (2) Add 124.59 mg (0.75 mmol) of 1,4-BDC (terephthalic acid) to the solution in step (1), and continue stirring until 1,4-BDC is completely dissolved; quickly inject 0.8 ml of TEA (triethylamine), and stir for 5 min to form a uniform colloidal suspension; (3) Under closed conditions, sonicate the colloidal suspension in step (2) for 1 h to promote the formation of the framework; the product is collected by centrifugation, and then washed with DMF and ethanol and dried at 60 o °C to finally obtain a two-dimensional ME-MOFs catalyst.

[0029] The catalyst prepared in this example was subjected to the following tests: Figure 1 is the XRD pattern of the two-dimensional ME-MOFs catalyst of this example. It can be seen from the figure that the catalyst prepared by the preparation method disclosed in the present invention is consistent with the simulated peaks of the MOFs material, indicating the successful synthesis of the two-dimensional ME-MOFs material.

[0030] Figure 2 is the XPS pattern of the two-dimensional ME-MOFs catalyst of this example. It can be seen from the figure that the two-dimensional ME-MOFs catalyst disclosed in the present invention is mainly composed of four metal elements: nickel, cobalt, iron, and molybdenum, indicating that the introduction and combination of different components in the sample are well reflected.

[0031] Figure 3SEM pattern of the two-dimensional ME-MOFs catalyst of this example. It can be seen from the figure that the two-dimensional ME-MOFs catalyst disclosed by the present invention presents a typical two-dimensional flake structure, which can expose more active sites.

[0032] The catalyst prepared in this example, commercial Pt / C and RuO2 catalysts were respectively placed in an alkaline medium for comparison. As Figure 4 and Figure 5 shown, wherein the electrolyte solution is 1 M KOH. It can be seen from Figure 4 that the overpotentials of the oxygen evolution (OER) performance of the catalyst prepared by the present invention at current densities of 10 mA∙cm -2 and 100 mA∙cm -2 are 267 mV and 371 mV respectively, which are superior to the performance of RuO2 (298 mV and 436 mV) under the same conditions. It can be seen from Figure 5 that the overpotential of the hydrogen evolution (HER) performance of the catalyst prepared by the present invention at a current density of 200 mA∙cm -2 is 667 mV, and the overpotential of Pt / C under the same conditions is 677 mV, indicating that the two-dimensional ME-MOFs catalyst prepared by the present invention has hydrogen evolution performance equivalent to or slightly better than that of Pt / C at high current densities.

[0033] Example 2 Prepare a two-dimensional ME-MOFs catalyst with a room temperature ultrasonic treatment time of 0.5 h. The steps are as follows: (1) Weigh 44.57 mg (0.1875 mmol) of NiCl2·6H2O, 44.61 mg (0.1875 mmol) of CoCl2·6H2O, 50.68 mg (0.1875 mmol) of FeCl3·6H2O and 51.23 mg (0.1875 mmol) of MoCl5 four metal salts respectively, and dissolve them in a mixed solution of 32 ml of dimethylformamide (DMF), 2 ml of ethanol (C2H5OH) and 2 ml of water (H2O), and stir well to ensure complete dissolution; (2) Add 124.59 mg (0.75 mmol) of 1,4-BDC (terephthalic acid) to the solution in step (1), and continue to stir until 1,4-BDC is completely dissolved; quickly inject 0.8 ml of TEA (triethylamine), and stir for 5 min to form a uniform colloidal suspension; (3) Under closed conditions, ultrasonically treat the colloidal suspension in step (2) for 0.5 h to promote the formation of the framework; the product is collected by centrifugation, and then washed with DMF and ethanol and dried at 60 oC drying, and finally obtaining the two-dimensional ME-MOFs catalyst.

[0034] Example 3 To prepare a two-dimensional ME-MOFs catalyst with a room temperature ultrasonic treatment time of 2 h, the steps are as follows: (1) Weigh 44.57 mg (0.1875 mmol) of NiCl2·6H2O, 44.61 mg (0.1875 mmol) of CoCl2·6H2O, 50.68 mg (0.1875 mmol) of FeCl3·6H2O, and 51.23 mg (0.1875 mmol) of MoCl5, four metal salts respectively, and dissolve them in a mixed solution of 32 ml of dimethylformamide (DMF), 2 ml of ethanol (C2H5OH), and 2 ml of water (H2O). Stir well to ensure complete dissolution; (2) Add 124.59 mg (0.75 mmol) of 1,4-BDC (terephthalic acid) to the solution in step (1), and continue stirring until 1,4-BDC is completely dissolved; quickly inject 0.8 ml of TEA (triethylamine), and stir for 5 min to form a uniform colloidal suspension; (3) Under airtight conditions, ultrasonically treat the colloidal suspension in step (2) for 2 h to promote the formation of the framework; the product is collected by centrifugation, and then washed with DMF and ethanol and dried at 60 o C drying, and finally obtaining the two-dimensional ME-MOFs catalyst.

[0035] Example 4 To prepare a two-dimensional ME-MOFs catalyst with a room temperature ultrasonic treatment time of 3 h, the steps are as follows: (1) Weigh 44.57 mg (0.1875 mmol) of NiCl2·6H2O, 44.61 mg (0.1875 mmol) of CoCl2·6H2O, 50.68 mg (0.1875 mmol) of FeCl3·6H2O, and 51.23 mg (0.1875 mmol) of MoCl5, four metal salts respectively, and dissolve them in a mixed solution of 32 ml of dimethylformamide (DMF), 2 ml of ethanol (C2H5OH), and 2 ml of water (H2O). Stir well to ensure complete dissolution; (2) Add 124.59 mg (0.75 mmol) of 1,4-BDC (terephthalic acid) to the solution in step (1), and continue stirring until 1,4-BDC is completely dissolved; quickly inject 0.8 ml of TEA (triethylamine), and stir for 5 min to form a uniform colloidal suspension; (3) Under airtight conditions, the colloidal suspension in step (2) was ultrasonically treated for 3 h to promote the formation of the framework; the product was collected by centrifugation, then washed with DMF and ethanol and dried at 60 o °C to finally obtain the two-dimensional ME-MOFs catalyst.

[0036] Example 5 To prepare a two-dimensional ME-MOFs catalyst with a room temperature ultrasonic treatment time of 4 h, the steps are as follows: (1) Weigh 44.57 mg (0.1875 mmol) of NiCl2·6H2O, 44.61 mg (0.1875 mmol) of CoCl2·6H2O, 50.68 mg (0.1875 mmol) of FeCl3·6H2O, and 51.23 mg (0.1875 mmol) of MoCl5, four metal salts, and dissolve them in a mixed solution of 32 ml of dimethylformamide (DMF), 2 ml of ethanol (C2H5OH), and 2 ml of water (H2O), and stir well to ensure complete dissolution; (2) Add 124.59 mg (0.75 mmol) of 1,4-BDC (terephthalic acid) to the solution in step (1), continue stirring until 1,4-BDC is completely dissolved; quickly inject 0.8 ml of TEA (triethylamine), and stir for 5 min to form a uniform colloidal suspension; (3) Under airtight conditions, the colloidal suspension in step (2) was ultrasonically treated for 4 h to promote the formation of the framework; the product was collected by centrifugation, then washed with DMF and ethanol and dried at 60 o °C to finally obtain the two-dimensional ME-MOFs catalyst.

[0037] Example 6 A preparation method of a two-dimensional medium-entropy metal-organic framework catalyst, the steps are as follows: (1) Dissolve Ni(CH3COO)2·4H2O, Co(CH3COO)2·4H2O, FeCl3·6H2O, and MoCl5 in a mixed solution of DMF, ethanol, and water to prepare a metal salt solution, and the molar ratio of Ni(CH3COO)2·4H2O, Co(CH3COO)2·4H2O, FeCl3·6H2O, and MoCl5 is 1.2:0.7:1.2:0.7, and the volume ratio of DMF, ethanol, and water is 10:1:1; (2) Add 1,4-benzenedicarboxylic acid to the metal salt solution in step (1), and the molar ratio of 1,4-benzenedicarboxylic acid to the metal salt is 2:1, stir to dissolve it, and quickly inject triethylamine after dissolution, and the molar ratio of triethylamine to 1,4-benzenedicarboxylic acid is 4:1, stir and form a uniform colloidal suspension; (3) Under airtight conditions, the colloidal suspension obtained in step (2) was ultrasonically treated for 0.5 h. The product was collected by centrifugation and then washed and dried to obtain the two-dimensional ME-MOFs catalyst.

[0038] Example 7 A method for preparing a two-dimensional medium-entropy metal-organic framework catalyst, comprising the following steps: (1) Ni(CH3COO)2·4H2O, Co(CH3COO)2·4H2O, FeCl3·6H2O and MoCl5 were dissolved in a mixed solution of DMF, ethanol and water to prepare a metal salt solution. The molar ratio of Ni(CH3COO)2·4H2O, Co(CH3COO)2·4H2O, FeCl3·6H2O and MoCl5 was 1.2:0.8:1.2:0.8, and the volume ratio of DMF, ethanol and water was 16:1:1; (2) 1,4-benzenedicarboxylic acid was added to the metal salt solution obtained in step (1). The molar ratio of 1,4-benzenedicarboxylic acid to the metal salt was 1:2. The mixture was stirred until dissolved, and then triethylamine was quickly injected. The molar ratio of triethylamine to 1,4-benzenedicarboxylic acid was 5:1. The mixture was stirred to form a homogeneous colloidal suspension; (3) Under airtight conditions, the colloidal suspension obtained in step (2) was ultrasonically treated for 2 h. The product was collected by centrifugation and then washed and dried to obtain the two-dimensional ME-MOFs catalyst.

[0039] Example 8 A method for preparing a two-dimensional medium-entropy metal-organic framework catalyst, comprising the following steps: (1) Ni(NO3)2·6H2O, Co(NO3)2·6H2O, Fe(NO3)3·9H2O and MoCl5 were dissolved in a mixed solution of DMF, ethanol and water to prepare a metal salt solution. The molar ratio of Ni(NO3)2·6H2O, Co(NO3)2·6H2O, Fe(NO3)3·9H2O and MoCl5 was 1.2:0.8:1.2:0.8, and the volume ratio of DMF, ethanol and water was 8:1:1; (2) 1,4-benzenedicarboxylic acid was added to the metal salt solution obtained in step (1). The molar ratio of 1,4-benzenedicarboxylic acid to the metal salt was 1:1. The mixture was stirred until dissolved, and then triethylamine was quickly injected. The molar ratio of triethylamine to 1,4-benzenedicarboxylic acid was 4:1. The mixture was stirred to form a homogeneous colloidal suspension; (3) Under airtight conditions, the colloidal suspension obtained in step (2) was ultrasonically treated for 4 h. The product was collected by centrifugation and then washed and dried to obtain the two-dimensional ME-MOFs catalyst.

[0040] The preparation method of a two-dimensional ME-MOFs catalyst prepared by room-temperature ultrasonic treatment provided by the present invention and its application in electrocatalysis have been introduced in detail above. Specific examples are used in this article to elaborate on the principle and implementation manner of the present invention. The description of the above embodiments is only used to help understand the method and its core idea of the present invention. The technical features of the above embodiments can be combined arbitrarily. For the sake of brevity of description, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, it should be considered as the scope recorded in this specification.

[0041] The above embodiments only represent several implementation manners of the present invention, and their descriptions are relatively specific and detailed, but they should not be construed as limiting the scope of the invention patent. It should be noted that for those of ordinary skill in the art, without departing from the concept of the present invention, several modifications and improvements can still be made, and these all belong to the protection scope of the present invention. Therefore, the protection scope of the present invention patent shall be subject to the appended claims.

Claims

1. A method for preparing a two-dimensional medium-entropy metal-organic framework catalyst, characterized in that: Here are the steps: (1) dissolving Ni salt, Co salt, Fe salt and Mo salt in a mixed solution of DMF, ethanol and water to prepare a metal salt solution; (2) adding 1,4-phthalic acid to the metal salt solution in step (1), stirring to dissolve it, and then quickly injecting triethylamine after dissolution, stirring to form a uniform colloidal suspension; (3) Under closed conditions, subjecting the colloidal suspension of step (2) to ultrasonic treatment; The products were collected by centrifugation, followed by washing and drying to obtain the two-dimensional ME-MOFs catalyst.

2. The method for preparing a two-dimensional medium-entropy metal-organic framework catalyst according to claim 1, characterized in that: The Ni salt, Co salt, Fe salt and Mo salt in step (1) are NiCl2·6H2O, CoCl2·6H2O, FeCl3·6H2O and MoCl5 respectively.

3. The method for preparing a two-dimensional medium-entropy metal-organic framework catalyst according to claim 1, characterized in that: The Ni salt in step (1) is Ni(CH3COO)2·4H2O or Ni(NO3)2·6H2O, the Co salt is Co(CH3COO)2·4H2O or Co(NO3)2·6H2O; the Fe salt is Fe(NO3)3·9H2O, and the Mo salt is MoCl5.

4. The method for preparing the two-dimensional medium entropy metal-organic framework catalyst according to claims 1-3, characterized in that: The molar ratio of the Ni salt, Co salt, Fe salt and Mo salt in the step (1) is (0.7-1.2): (0.7-1.2): (0.7-1.2): (0.7-1.2).

5. The method for preparing a two-dimensional medium-entropy metal-organic framework catalyst according to claim 1, characterized in that: The volume ratio of DMF, ethanol and water in step (1) is (16-8):1:

1.

6. The method for preparing a two-dimensional medium entropy metal-organic framework catalyst according to claim 1, characterized in that: The ratio of the amount of 1,4-phthalic acid to the amount of the metal salt in the step (2) is (1:1) to (1:2).

7. The method for preparing a two-dimensional medium entropy metal-organic framework catalyst according to claim 1, characterized in that: The amount of 1,4-phthalic acid added in step (2) is: based on 100 mg of 1,4-phthalic acid, add 0.5-2 ml of triethylamine.

8. The method for preparing a two-dimensional medium entropy metal-organic framework catalyst according to claim 1, characterized in that: The ultrasonic reaction time in step (3) is 0.5 to 4 h.

9. A two-dimensional medium entropy metal-organic framework catalyst prepared by any preparation method of claims 1-7, characterized in that: The catalyst is composed of four metal elements; the entropy metal-organic skeleton catalyst is a two-dimensional sheet structure.

10. Use of the two-dimensional medium-entropy metal-organic framework catalyst according to claim 8 in oxygen evolution and hydrogen evolution reactions in alkaline or acidic media.

Images