Preparation method of ultrathin high-entropy molybdate catalyst and application of ultrathin high-entropy molybdate catalyst in OER

Abstract

The invention belongs to the technical field of electro-catalysis, and particularly relates to a preparation method of an ultrathin high-entropy molybdate catalyst and application of the ultrathin high-entropy molybdate catalyst in OER. The invention discloses an ultrathin high-entropy molybdate catalyst prepared by a solvothermal method, which is composed of multiple metal elements such as Ru, Co, Ni and the like and Mo, forms a high-entropy metal ion coordination environment, and shows excellent oxygen evolution catalytic performance and structural stability. The preparation method has the specific advantages that (1) the high-entropy molybdate oxide which is good in dispersity, 2-3nm in thickness and similar to a two-dimensional parallelogram nanosheet in morphology can be prepared; (2) elements are uniformly distributed, various metal ions synergistically generate a high-entropy effect, and an electronic structure is regulated and controlled to improve the catalytic performance; (3) the catalyst has high catalytic activity, and is low in overpotential and strong in stability under large current density of 1A. Cm <-2 >; and (4) the preparation process is mild and simple, and high-temperature annealing and complex templates are not needed.

Description

Technical Field

[0001] The present invention belongs to the technical field of electrocatalysis, and particularly relates to a preparation method of an ultrathin high-entropy molybdate catalyst and an application thereof in OER. Background Art

[0002] The oxygen evolution reaction (OER) is a key step in water splitting and renewable energy conversion, but its multi-electron reaction steps and slow kinetics severely limit the overall reaction efficiency. In recent years, transition metal elements have been widely studied due to their high activity and huge regulatory space. However, in the OER reaction, the catalyst is often under harsh conditions of strong acid, strong alkalinity and strong oxidizing properties, which makes it difficult for it to have both high activity and high stability. This problem is particularly prominent in industrial-grade high current density (>500mA·cm -2 ) is particularly prominent, which greatly hinders the industrial development of OER.

[0003] High entropy oxides are one of the catalysts with great development potential. Their high entropy effect originates from the synergistic effect of multiple metal elements, which can achieve energy band regulation and significantly improve catalytic performance. At the same time, their unique diffusion hysteresis effect further improves their catalytic stability. In addition, the two-dimensional ultra-thin structure can further synergistically enhance the activity and stability of the catalyst by providing abundant exposed active sites and shorter ion migration paths. Therefore, it is necessary to develop new methods for preparing high entropy oxide catalysts to utilize the energy band regulation, diffusion hysteresis effect and two-dimensional ultra-thin structure of the high entropy effect to improve their activity and stability in OER. Summary of the Invention

[0004] In order to overcome the above-mentioned shortcomings of the prior art, the present invention provides an ultra-thin high-entropy molybdate catalyst with excellent activity and stability in high-concentration strong alkaline OER reactions and high-current OER reactions, and can be prepared at an industrial level at low cost through a controllable solvent thermal synthesis method.

[0005] In order to achieve the above object, the technical solution adopted by the present invention is:

[0006] A first aspect of the present invention provides a method for preparing an ultrathin high entropy molybdate catalyst, comprising the following steps:

[0007] S1. Adding a metal salt and a molybdate to a mixed solution of a surfactant, water, and ethylene glycol and mixing them uniformly, wherein the metal salt is selected from at least four of the group consisting of Mn, Fe, Co, Ni, Cu, Zn, Ru, Pt, Ir, and Pd, and the surfactant is PVP, SDS, or SDBS;

[0008] S2. The mixed solution in S1 is subjected to a hydrothermal reaction, and the obtained reaction product is washed, dried and ground to prepare an ultrathin high entropy molybdate powder.

[0009] Preferably, in S1, the molar concentrations of the metal salts are the same, and the molar ratio of the total metal ions to the molybdate ions is 1:1.

[0010] Preferably, in S1, the metal salt is selected from four metal salts of Ru, Fe, Co, and Ni, or four metal salts of Ir, Fe, Co, and Ni, or four metal salts of Pt, Fe, Co, and Ni.

[0011] Preferably, in S1, the usage ratio of surfactant, water and ethylene glycol is 100-500 mg: 1-5 mL: 10-50 mL.

[0012] Preferably, in S2, the temperature of the hydrothermal reaction is 150-200°C and the time is 10-20 hours.

[0013] Preferably, in S2, the washing is to wash the reaction product 3-5 times in sequence with low-temperature ultrapure water and anhydrous ethanol and then centrifuge to remove the washing solution.

[0014] The second aspect of the present invention provides an ultra-thin high-entropy molybdate catalyst prepared by the preparation method described in the first aspect.

[0015] The third aspect of the present invention provides an application of the ultrathin high entropy molybdate catalyst described in the second aspect in the oxygen evolution reaction (OER).

[0016] Preferably, the oxygen evolution reaction includes a high-concentration, strongly alkaline oxygen evolution reaction and / or a high-current oxygen evolution reaction.

[0017] Preferably, before use, the ultra-thin high entropy molybdate catalyst is made into an electrode sheet: the ultra-thin high entropy molybdate catalyst, a conductive agent, and a binder are dissolved in a solvent, and then coated on a conductive substrate, and dried to form an electrode sheet.

[0018] More preferably, the conductive agent includes carbon black, graphene, carbon nanotubes, and carbon fibers; the binder includes Nafion, polyvinylidene fluoride (PVDF), sodium carboxymethyl cellulose (CMC), styrene-butadiene rubber (SBR), and polytetrafluoroethylene (PTFE); and the conductive substrate includes conductive carbon paper, carbon cloth, nickel foam, graphene film, titanium foil, stainless steel mesh, copper foam, and conductive glass.

[0019] More preferably, the mass ratio of the ultra-thin high entropy molybdate catalyst to the conductive agent is 1-5:1-3.

[0020] More preferably, the solvent is isopropyl alcohol, or a mixed solution of water and ethanol (volume ratio 1:1).

[0021] More preferably, the binder is Nafion, and the usage ratio of Nafion to the ultra-thin high entropy molybdate catalyst is 30-50 μL: 2-5 mg.

[0022] Compared with the prior art, the present invention has the following beneficial effects:

[0023] The present invention discloses an ultrathin high-entropy molybdate catalyst prepared by a solvothermal method. The catalyst is composed of multiple metal elements (such as Ru, Co, Ni, Fe, Mn, Cu, etc.) and Mo to form a high-entropy metal ion coordination environment, exhibiting excellent oxygen evolution catalytic performance and structural stability. Even in high-concentration, strongly alkaline OER reactions and high-current OER reactions, it still has excellent activity and stability.

[0024] Specifically, the present invention has the following advantages:

[0025] (1) High-entropy molybdate oxides with good dispersion, thickness of only 2-3 nm, and a two-dimensional parallelogram nanosheet morphology can be prepared;

[0026] (2) The elements are evenly distributed, and the synergistic effect of multiple metal ions produces a high entropy effect, which regulates the electronic structure and thus improves the catalytic performance;

[0027] (3) High catalytic activity, in a high concentration alkaline environment (such as 1M KOH) and a high current density (such as 1A·cm -2 ) has low overpotential and high stability;

[0028] (4) The preparation method is gentle and simple, without the need for high-temperature annealing or complex templates. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 CV graphs obtained after OER testing of the electrode sheets of Examples 1-3 (Ru represents Ru-(FeCoNi)MoO4, Ir represents Ir-(FeCoNi)MoO4, and Pt represents Pt-(FeCoNi)MoO4);

[0030] Figure 2 CV graphs obtained after OER testing of the electrode sheets of Example 1 and Comparative Examples 1-3;

[0031] Figure 3 This is a CV graph of the electrode sheet of Example 4 obtained after OER testing;

[0032] Figure 4 This is a graph showing the long-term stability test of the electrode sheet OER in Example 4;

[0033] Figure 5This is the AFM analysis image of the Ru-(FeCoNi)MoO4 catalyst powder prepared in Example 4. DETAILED DESCRIPTION

[0034] The following is a further description of specific embodiments of the present invention. It should be noted that the description of these embodiments is intended to facilitate understanding of the present invention and does not constitute a limitation of the present invention. In addition, the technical features involved in the various embodiments of the present invention described below may be combined with each other as long as they do not conflict with each other.

[0035] The experimental methods in the following examples are conventional methods unless otherwise specified, and the experimental materials used in the following examples are commercially available unless otherwise specified.

[0036] Example 1: Preparation of carbon paper loaded with Ru-(FeCoNi)MoO4 catalyst

[0037] (1) Prepare 100 mg / L RuCl4 solution, 0.75 mol / L FeSO4 solution, Ni(NO3)2 solution, Co(NO3)2 solution, and 0.75 mol / L Na2MoO4 solution.

[0038] (2) In a 100 mL hydrothermal reactor, add 200 mg of SDBS, 5 mL of water, and 40 mL of ethylene glycol solution and stir to dissolve.

[0039] (3) Under vigorous stirring, add 100 mL of 0.75 mol / L FeSO4 solution, Ni(NO3)2 solution, Co(NO3)2 solution, 300 mL of 0.75 mol / L Na2MoO4 solution and 100 μL of 100 mg / L RuCl4 solution in sequence. The molar ratio of total metal ions to molybdate ions must be 1:1.

[0040] (4) Place the hydrothermal kettle in an oven at 200°C and heat for 10 hours.

[0041] (5) Wash the precipitate 3-5 times with ultrapure water and anhydrous ethanol at 2°C and centrifuge to remove the washing solution.

[0042] (6) Freeze-dry the precipitate at -80°C for 3 days.

[0043] (7) The precipitate was taken out and ground into flour to obtain Ru-(FeCoNi)MoO4 powder.

[0044] (8) Ink preparation: 4 mg of the obtained Ru-(FeCoNi)MoO4 powder and 1 mg of conductive carbon black were mixed, and then 480 μL of ultrapure water, 480 μL of anhydrous ethanol, and 40 μL of Nafion were added, and ultrasonicated for 1 h.

[0045] (9) Preparation of electrode sheet: Use a pipette to take 100 μL of ink and evenly apply it on the conductive carbon paper (1×1 cm 2 ) and dried using infrared lamps.

[0046] (10) OER performance test: A three-electrode system was constructed using the electrode sheet prepared in step (9) as the working electrode, Hg / HgO as the reference electrode, and a graphite rod as the counter electrode. CV tests were performed in 1 M KOH.

[0047] Example 2: Preparation of carbon paper loaded with Ir-(FeCoNi)MoO4 catalyst

[0048] (1) Prepare 100 mg / L IrCl3 solution, 0.75 mol / L FeSO4 solution, Ni(NO3)2 solution, Co(NO3)2 solution, and 0.75 mol / L Na2MoO4 solution.

[0049] (2) In a 100 mL hydrothermal reactor, add 200 mg of SDBS, 5 mL of water, and 40 mL of ethylene glycol solution and stir to dissolve.

[0050] (3) Under vigorous stirring, add 100 mL of 0.75 mol / L FeSO4 solution, Ni(NO3)2 solution, Co(NO3)2 solution, 300 mL of 0.75 mol / L Na2MoO4 solution and 100 μL of 100 mg / L IrCl3 solution in sequence. This process requires ensuring that the molar ratio of total metal ions to molybdate ions is 1:1.

[0051] (4) Place the hydrothermal kettle in an oven at 200°C and heat for 10 hours.

[0052] (5) Wash the precipitate 3-5 times with ultrapure water and anhydrous ethanol at 2°C and centrifuge to remove the washing solution.

[0053] (6) Freeze-dry the precipitate at -80°C for 3 days.

[0054] (7) The precipitate was removed and ground into a floury state to obtain Ir-(FeCoNi)MoO4 powder.

[0055] (8) Ink preparation: 4 mg of the obtained Ir-(FeCoNi)MoO4 powder and 1 mg of conductive carbon black were mixed, and then 480 μL of ultrapure water, 480 μL of anhydrous ethanol, and 40 μL of Nafion were added, and ultrasonicated for 1 h.

[0056] (9) Preparation of electrode sheet: Use a pipette to take 100 μL of ink and evenly apply it on the conductive carbon paper (1×1 cm 2 ) and dried using infrared lamps.

[0057] (10) OER performance test: A three-electrode system was constructed using the electrode sheet prepared in step (9) as the working electrode, Hg / HgO as the reference electrode, and a graphite rod as the counter electrode. CV tests were performed in 1 M KOH.

[0058] Example 3: Preparation of carbon paper loaded with Pt-(FeCoNi)MoO4 catalyst

[0059] (1) Prepare 100 mg / L H2PtCl6 solution, 0.75 mol / L FeSO4 solution, Ni(NO3)2 solution, Co(NO3)2 solution, and 0.75 mol / L Na2MoO4 solution.

[0060] (2) In a 100 mL hydrothermal reactor, add 200 mg of SDBS, 5 mL of water, and 40 mL of ethylene glycol solution and stir to dissolve.

[0061] (3) Under vigorous stirring, add 100 mL of 0.75 mol / L FeSO4 solution, Ni(NO3)2 solution, Co(NO3)2 solution, 300 mL of 0.75 mol / L Na2MoO4 solution and 100 μL of 100 mg / L H2PtCl6 solution in sequence. The molar ratio of total metal ions to molybdate ions must be 1:1.

[0062] (4) Place the hydrothermal kettle in an oven at 200°C and heat for 10 hours.

[0063] (5) Wash the precipitate 3-5 times with ultrapure water and anhydrous ethanol at 2°C and centrifuge to remove the washing solution.

[0064] (6) Freeze-dry the precipitate at -80°C for 3 days.

[0065] (7) The precipitate was removed and ground into a floury state to obtain Ir-(FeCoNi)MoO4 powder.

[0066] (8) Ink preparation: 4 mg of the obtained Ir-(FeCoNi)MoO4 powder and 1 mg of conductive carbon black were mixed, and then 480 μL of ultrapure water, 480 μL of anhydrous ethanol, and 40 μL of Nafion were added, and ultrasonicated for 1 h.

[0067] (9) Preparation of electrode sheet: Use a pipette to take 100 μL of ink and evenly apply it on the conductive carbon paper (1×1 cm 2 ) and dried using infrared lamps.

[0068] (10) OER performance test: A three-electrode system was constructed using the electrode sheet prepared in step (9) as the working electrode, Hg / HgO as the reference electrode, and a graphite rod as the counter electrode. CV tests were performed in 1 M KOH.

[0069] Example 4: Preparation of nickel foam loaded with Ru-(FeCoNi)MoO4 catalyst

[0070] (1) Prepare Ru-(FeCoNi)MoO4 powder according to steps (1)-(7) of Example 1.

[0071] (2) Prepare ink: Mix 2 mg of powder and 2 mg of conductive carbon black, then add 200 μL of isopropyl alcohol and 30 μL of Nafion. Ultrasonicate for 1 hour.

[0072] (3) Preparation of electrode sheet: Use a pipette to evenly apply 100 μL of ink on the nickel foam (1×1 cm 2 ) and dried using infrared lamps.

[0073] (4) OER performance test: A three-electrode system was constructed using the electrode sheet prepared in step (9) as the working electrode, Hg / HgO as the reference electrode, and a graphite rod as the counter electrode. CV tests were performed in 6 M KOH.

[0074] Comparative Example 1: Preparation of carbon paper loaded with FeMoO4 catalyst

[0075] (1) Prepare 0.75 mol / L FeSO4 solution and 0.75 mol / L Na2MoO4 solution.

[0076] (2) In a 100 mL hydrothermal reactor, add 200 mg of SDBS, 5 mL of water, and 40 mL of ethylene glycol solution and stir to dissolve.

[0077] (3) Under vigorous stirring, add 100 mL of 0.75 mol / L FeSO4 solution and 100 mL of 0.75 mol / L Na2MoO4 solution in sequence. This process must ensure that the molar ratio of total metal ions to molybdate ions is 1:1.

[0078] (4) Place the hydrothermal kettle in an oven at 200°C and heat for 10 hours.

[0079] (5) Wash the precipitate 3-5 times with ultrapure water and anhydrous ethanol at 2°C and centrifuge to remove the washing solution.

[0080] (6) Freeze-dry the precipitate at -80°C for 3 days.

[0081] (7) Take out the precipitate and grind it into flour to obtain FeMoO4 powder.

[0082] (8) Ink preparation: 4 mg of the obtained FeMoO4 powder and 1 mg of conductive carbon black were mixed, and then 480 μL of ultrapure water, 480 μL of anhydrous ethanol, and 40 μL of Nafion were added, and ultrasonicated for 1 h.

[0083] (9) Preparation of electrode sheet: Use a pipette to take 100 μL of ink and evenly apply it on the conductive carbon paper (1×1 cm 2 ) and dried using infrared lamps.

[0084] (10) OER performance test: A three-electrode system was constructed using the electrode sheet prepared in step (9) as the working electrode, Hg / HgO as the reference electrode, and a graphite rod as the counter electrode. CV tests were performed in 1 M KOH.

[0085] Comparative Example 2: Preparation of carbon paper loaded with (FeNi)MoO4 catalyst

[0086] (1) Prepare a 0.75 mol / L FeSO4 solution, a 0.75 mol / L Ni(NO3)2 solution, and a 0.75 mol / L Na2MoO4 solution.

[0087] (2) In a 100 mL hydrothermal reactor, add 200 mg of SDBS, 5 mL of water, and 40 mL of ethylene glycol solution and stir to dissolve.

[0088] (3) Under vigorous stirring, add 100 mL of 0.75 mol / L FeSO4 solution, Ni(NO3)2 solution and 200 mL of 0.75 mol / L Na2MoO4 solution in sequence. During this process, the molar ratio of total metal ions to molybdate ions must be 1:1.

[0089] (4) Place the hydrothermal kettle in an oven at 200°C and heat for 10 hours.

[0090] (5) Wash the precipitate 3-5 times with ultrapure water and anhydrous ethanol at 2°C and centrifuge to remove the washing solution.

[0091] (6) Freeze-dry the precipitate at -80°C for 3 days.

[0092] (7) Remove the precipitate and grind it into flour to obtain (FeNi)MoO4 powder.

[0093] (8) Ink preparation: 4 mg of the obtained (FeNi)MoO4 powder and 1 mg of conductive carbon black were mixed, and then 480 μL of ultrapure water, 480 μL of anhydrous ethanol, and 40 μL of Nafion were added, and ultrasonicated for 1 h.

[0094] (9) Preparation of electrode sheet: Use a pipette to take 100 μL of ink and evenly apply it on the conductive carbon paper (1×1 cm 2 ) and dried using infrared lamps.

[0095] (10) OER performance test: A three-electrode system was constructed using the electrode sheet prepared in step (9) as the working electrode, Hg / HgO as the reference electrode, and a graphite rod as the counter electrode. CV tests were performed in 1 M KOH.

[0096] Comparative Example 3: Preparation of carbon paper loaded with (FeCoNi)MoO4 catalyst

[0097] (1) Prepare FeSO4 solution with a concentration of 0.75 mol / L, Ni(NO3)2 solution, Co(NO3)2 solution, and Na2MoO4 solution with a concentration of 0.75 mol / L.

[0098] (2) In a 100 mL hydrothermal reactor, add 200 mg of SDBS, 5 mL of water, and 40 mL of ethylene glycol solution and stir to dissolve.

[0099] (3) Under vigorous stirring, add 100 mL of 0.75 mol / L FeSO4 solution, Ni(NO3)2 solution, Co(NO3)2 solution, and 300 mL of 0.75 mol / L Na2MoO4 solution in sequence. This process must ensure that the molar ratio of total metal ions to molybdate ions is 1:1.

[0100] (4) Place the hydrothermal kettle in an oven at 200°C and heat for 10 hours.

[0101] (5) Wash the precipitate 3-5 times with ultrapure water and anhydrous ethanol at 2°C and centrifuge to remove the washing solution.

[0102] (6) Freeze-dry the precipitate at -80°C for 1-3 days.

[0103] (7) Remove the precipitate and grind it into flour to obtain (FeCoNi)MoO4 powder.

[0104] (8) Ink preparation: 4 mg of the obtained (FeCoNi)MoO4 powder and 1 mg of conductive carbon black were mixed, and then 480 μL of ultrapure water, 480 μL of anhydrous ethanol, and 40 μL of Nafion were added, and ultrasonicated for 1 h.

[0105] (9) Preparation of electrode sheet: Use a pipette to take 100 μL of ink and evenly apply it on the conductive carbon paper (1×1 cm 2 ) and dried using infrared lamps.

[0106] (10) OER performance test: A three-electrode system was constructed using the electrode sheet prepared in step (9) as the working electrode, Hg / HgO as the reference electrode, and a graphite rod as the counter electrode. CV tests were performed in 1 M KOH.

[0107] Experimental example:

[0108] The catalysts prepared in Examples 1-4 and Comparative Examples 1-3 were characterized using the following method:

[0109] like Figure 1 As shown in the CV diagram, the electrode sheets of Examples 1-3 were subjected to OER tests in 1M KOH electrolyte, among which the high entropy catalyst containing the precious metal Ru had the best performance.

[0110] like Figure 2 As shown in the CV graph, the electrode sheets of Examples 1-3 and Control Examples 1-3 were subjected to OER tests in 1M KOH electrolyte. In contrast, the high entropy Ru-(FeCoNi)MoO4 catalyst showed very high activity at 10 mA cm -2 At a current density of 1.5 GHz, the overpotential is only 200 mV, surpassing several other medium and low entropy molybdates.

[0111] like Figure 3 As shown in the CV graph, the electrode sheet of Example 4 was subjected to OER test in 1M KOH electrolyte. It has high activity at high current density, 1A·cm -2 The lower overpotential is only 442mV.

[0112] like Figure 4 As shown in the figure, the electrode sheet of Example 4 was subjected to a long-term OER stability test in a 1M KOH electrolyte. -2 Under these conditions, the catalyst still showed ultra-high stability and no obvious performance degradation within 350 hours. Linear fitting analysis showed that its performance degradation rate was only 0.22mV·h -1 .

[0113] like Figure 5As shown, AFM analysis of the Ru-(FeCoNi)MoO4 catalyst powder prepared in Example 4 reveals that the Ru-(FeCoNi)MoO4 nanosheets (excluding the substrate) are less than 3 nm thick, exhibiting an ultrathin parallelogram structure. Furthermore, the nanosheets prepared in Examples 1-3 also exhibit an ultrathin parallelogram structure, exhibiting thicknesses less than 3 nm.

[0114] The embodiments of the present invention are described in detail above, but the present invention is not limited to the described embodiments. It is apparent to those skilled in the art that various changes, modifications, substitutions, and variations of these embodiments may be made without departing from the principles and spirit of the present invention, and the changes still fall within the scope of protection of the present invention.

Claims

1. A method for preparing an ultrathin high entropy molybdate catalyst, characterized in that: The following steps are involved: S1. Adding a metal salt and a molybdate to a mixed solution of a surfactant, water, and ethylene glycol and mixing them uniformly, wherein the metal salt is selected from at least four of the group consisting of Mn, Fe, Co, Ni, Cu, Zn, Ru, Pt, Ir, and Pd, and the surfactant is PVP, SDS, or SDBS; S2. The mixed solution in S1 is subjected to a hydrothermal reaction, and the obtained reaction product is washed, dried and ground to prepare an ultrathin high entropy molybdate powder.

2. The method for preparing an ultrathin high entropy molybdate catalyst according to claim 1, wherein In S1, the molar concentrations of the metal salts are the same, and the molar ratio of the total metal ions to the molybdate ions is 1:

1.

3. The method for preparing an ultrathin high entropy molybdate catalyst according to claim 1, wherein In S1, the metal salt is selected from four metal salts of Ru, Fe, Co, and Ni, or four metal salts of Ir, Fe, Co, and Ni, or four metal salts of Pt, Fe, Co, and Ni.

4. The method for preparing an ultrathin high entropy molybdate catalyst according to claim 1, wherein In S1, the dosage ratio of surfactant, water and ethylene glycol is 100-500 mg: 1-5 mL: 10-50 mL.

5. The method for preparing an ultrathin high entropy molybdate catalyst according to claim 1, wherein In S2, the temperature of the hydrothermal reaction is 150-200°C and the time is 10-20 hours.

6. The method for preparing an ultrathin high entropy molybdate catalyst according to claim 1, wherein: In S2, the washing is to use low-temperature ultrapure water and anhydrous ethanol to wash the reaction product 3-5 times in sequence and then centrifuge to remove the washing solution.

7. An ultra-thin high-entropy molybdate catalyst prepared by the preparation method according to any one of claims 1 to 6.

8. Use of the ultrathin high entropy molybdate catalyst according to claim 7 in an oxygen evolution reaction.

9. The use according to claim 8, characterized in that The oxygen evolution reaction includes a high-concentration, strongly alkaline oxygen evolution reaction and / or a high-current oxygen evolution reaction.

10. The use according to claim 8, characterized in that Before use, the ultra-thin high entropy molybdate catalyst according to claim 7 is made into an electrode sheet: the ultra-thin high entropy molybdate catalyst, a conductive agent and a binder are dissolved in a solvent, and then coated on a conductive substrate, and dried to form an electrode sheet.

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