Method for preparing high-entropy spinel oxide nano material by fused salt protection method and application of high-entropy spinel oxide nano material
The preparation of high-entropy spinel oxide nanomaterials by molten salt protection method solves the problems of slow oxygen evolution reaction kinetics and high cost of precious metal catalysts during water electrolysis, and achieves efficient OER catalytic activity and low-cost preparation, which is suitable for large-scale production and industrial applications.
Patent Information
- Application Number
- CN202510184840.6
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-02-19
- Publication Date
- 2025-05-23
AI Technical Summary
In the prior art, the kinetics of the oxygen evolution reaction during water electrolysis are slow, resulting in high overpotential reaction, large power consumption, high hydrogen production costs, and high cost and scarcity of precious metal-based catalysts, which limits their large-scale application.
High-entropy spinel oxide nanomaterials were prepared by molten salt protection method. By mixing the aqueous solution of cobalt salt and other metal salts, trisodium citrate solution and potassium hexacyanocobaltate, stirring and reaction, mixing salt was added and heated to obtain high-entropy spinel oxide nanomaterials.
This method simplifies the preparation process, reduces costs, improves the oxygen evolution performance and OER catalytic activity of the material, and has the advantages of low cost, abundant resources and environmentally friendly. It is suitable for large-scale production and industrial applications.
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Figure CN120024941A_ABST
Abstract
Description
Technical Field
[0001] The present invention belongs to the technical field of nano material preparation and new energy, and specifically relates to a method for preparing high entropy spinel oxide nano material by a molten salt protection method and application thereof. Background Art
[0002] The information disclosed in this background technology section is only intended to enhance the understanding of the overall background of the invention, and should not necessarily be regarded as an admission or any form of suggestion that the information constitutes the prior art already known to a person skilled in the art.
[0003] The burning of fossil fuels will release a large amount of greenhouse gases, which will in turn aggravate global warming and climate change and affect the ecological balance. In addition, the burning of fossil fuels will cause environmental pollution and threaten people's health. The development of renewable energy can reduce the use of fossil fuels. Clean energy such as solar energy and wind energy has the advantage of being inexhaustible and can effectively reduce greenhouse gas emissions and protect the environment. At present, hydrogen energy is regarded as a green alternative energy to fossil fuels due to its high calorific value and pollution-free characteristics, and has broad application prospects.
[0004] With the rapid development of renewable energy (such as wind power and solar energy), the use of excess electricity to electrolyze water to produce hydrogen has become the main way to achieve green hydrogen energy. The water electrolysis reaction is divided into the hydrogen evolution reaction (HER) at the cathode and the oxygen evolution reaction (OER) at the anode. However, due to the slow kinetics of the oxygen evolution reaction, water electrolysis requires a large reaction overpotential, which leads to excessive power consumption and high hydrogen production costs. IrO 2 and RuO 2 Precious metal-based catalysts such as NH4+ and NH4+ exhibit excellent OER activity, but their large-scale application is limited by their high cost and scarcity. Therefore, it is urgent to develop low-cost, high-catalytically active transition metal catalysts as their alternatives.
[0005] Prussian blue analogs (PBAs) have great potential for development in OER electrocatalytic materials due to their unique three-dimensional open metal framework and easily adjustable components, but their poor conductivity and easily collapsed framework limit their catalytic performance. Summary of the invention
[0006] In view of the shortcomings of the prior art, the present invention provides a method and application of preparing high-entropy spinel oxide nanomaterials by molten salt protection method. The preparation process of the present invention is relatively simple, does not require complicated equipment and operation steps, is convenient for laboratory research and industrial production, and can quickly prepare high-entropy spinel oxide nanomaterials. -2When the overpotential of CoNiCuMnZnFe spinel oxide nanomaterial is 310mV, it shows its excellent oxygen evolution performance and efficient OER catalytic activity. It exhibits excellent activity in electrocatalytic reactions, has the advantages of low cost, abundant resources and environmental friendliness, and has important commercial application value and broad development prospects in the fields of energy and environmental protection.
[0007] In order to achieve the above object, the present invention adopts the following technical solution:
[0008] The first aspect of the present invention provides a method for preparing a high entropy spinel oxide nanomaterial by a molten salt protection method, which specifically comprises the following steps:
[0009] S1. Mixing aqueous solutions of cobalt salt and other metal salts, and then adding trisodium citrate to obtain solution I; dropping an aqueous solution of potassium hexacyanocobaltate into solution I to obtain solution II, and stirring to react, thereby obtaining Prussian blue and analogs containing different metal ions;
[0010] S2. Prussian blue analogues containing different metal ions are added to the mixed salt respectively, and high entropy spinel oxide nanomaterials are obtained after heating.
[0011] Preferably, in step S1, the other metal salts are selected from at least five of nickel salts, copper salts, manganese salts, zinc salts, iron salts, and chromium salts.
[0012] Preferably, in step S1, the molar ratio of the cobalt salt to other metal salts is 2:1-1.2; the molar ratio of the cobalt salt to trisodium citrate is 2:4-5; and the molar ratio of the potassium hexacyanocobaltate to the cobalt salt is 1-1.2:1.
[0013] Preferably, in step S1, the reaction solution obtained after the stirring reaction is centrifuged, washed and dried to obtain Prussian blue and analogues containing different metal ions; wherein the washing is washing with deionized water 2 to 3 times and washing with anhydrous ethanol 2 to 3 times respectively, and the drying is vacuum drying at 30 to 50°C for 8 to 20 hours.
[0014] Preferably, in step S2, the mixed salt is KNO 3 、NaNO 3 and NaNO 2 Composition, the KNO 3 、NaNO 3 and NaNO 2 The mass ratio of KNO is 50-55:5-8:35-45; further preferably, the KNO 3 、NaNO 3 and NaNO 2 The mass ratio is 53:7:40.
[0015] Preferably, in step S2, the Prussian blue analogs containing different metal ions are mixed with KNO 3 、NaNO 3 and NaNO 2 The mass ratio of the Prussian blue analogs containing different metal ions and KNO is 0.1:50-55:5-8:35-45; further preferably, the Prussian blue analogs containing different metal ions and KNO 3 、NaNO 3 and NaNO 2 The mass ratio is 0.1:53:7:40.
[0016] Preferably, in step S2, the temperature of the heating treatment is 280-350°C, and the time is 10-30 minutes; further preferably, the temperature of the heating treatment is 300°C, and the time is 15 minutes.
[0017] Preferably, in step S2, the product after the heating treatment is washed with deionized water to remove mixed salt impurities, and then vacuum dried at 30 to 50° C. for 10 to 24 hours to obtain a high entropy spinel oxide nanomaterial.
[0018] The second aspect of the present invention provides a high entropy spinel oxide nanomaterial, which is prepared by the method for preparing high entropy spinel oxide nanomaterial by the molten salt protection method described in the first aspect.
[0019] The third aspect of the present invention provides an application of the high entropy spinel oxide nanomaterial described in the second aspect in electrolyzed water.
[0020] Preferably, the three-electrode system used in the electrolysis of water is an electrode coated with the high-entropy spinel oxide nanomaterial described in the second aspect as a working electrode, a platinum electrode as a counter electrode, a Hg / HgO electrode as a reference electrode, 1 mol / L potassium hydroxide as an electrolyte, and a glass electrolytic cell as a reaction device.
[0021] Preferably, during the electrolysis of water, the current density reaches 10 mA cm -2 When the overpotential of the high entropy spinel oxide nanomaterial is 300-320 mV.
[0022] The beneficial effects achieved by one or more technical solutions of the present invention are as follows:
[0023] (1) The present invention utilizes the molten salt protection method to increase the content of high-valent ions in nanomaterials and increase the number of active sites, thereby greatly improving the oxygen evolution performance of the material. The synthesized powder has a small and uniform particle size, which is beneficial to improving the performance of the material. Different molten salts can be selected and the reaction conditions can be controlled, and the structure of the product can be regulated to meet different application requirements. Due to the simple process, the molten salt protection method is suitable for large-scale production and can meet the requirements of industrial applications.
[0024] (2) The present invention has a current density of 10 mA cm -2 When the overpotential of CoNiCuMnZnFe spinel oxide nanomaterials is 310mV, it shows its excellent oxygen evolution performance and efficient OER catalytic activity. It shows excellent activity in electrocatalytic reactions, has the advantages of low cost, abundant resources and environmental friendliness, and has important commercial application value and broad development prospects in the fields of energy and environmental protection. BRIEF DESCRIPTION OF THE DRAWINGS
[0025] The accompanying drawings in the specification, which constitute a part of the present invention, are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute improper limitations on the present invention.
[0026] Figure 1 This is the XRD spectrum of the high entropy spinel oxide nanomaterial prepared in Example 1 of the present invention;
[0027] Figure 2 The OER properties of the high entropy spinel oxide nanomaterials prepared in Examples 1 to 6 of the present invention. DETAILED DESCRIPTION
[0028] It should be noted that the following detailed descriptions are exemplary and are intended to provide further explanation of the present invention. Unless otherwise specified, all technical and scientific terms used in the present invention have the same meanings as those commonly understood by those skilled in the art to which the present invention belongs.
[0029] A first typical embodiment of the present invention provides a method for preparing a high entropy spinel oxide nanomaterial by a molten salt protection method, which specifically comprises the following steps:
[0030] S1. Mixing aqueous solutions of cobalt salt and other metal salts, and then adding trisodium citrate to obtain solution I; dropping an aqueous solution of potassium hexacyanocobaltate into solution I to obtain solution II, and stirring to react, thereby obtaining Prussian blue and analogs containing different metal ions;
[0031] S2. Prussian blue analogues containing different metal ions are added to the mixed salt respectively, and high entropy spinel oxide nanomaterials are obtained after heating.
[0032] In one or more examples of this implementation mode, in step S1, the other metal salts are selected from at least five of nickel salts, copper salts, manganese salts, zinc salts, iron salts, and chromium salts.
[0033] In one or more examples of this embodiment, in step S1, the molar ratio of the cobalt salt to other metal salts is 2:1-1.2; the molar ratio of the cobalt salt to trisodium citrate is 2:4-5; and the molar ratio of the potassium hexacyanocobaltate to the cobalt salt is 1-1.2:1.
[0034] In one or more embodiments of this implementation mode, in step S1, the reaction solution obtained after the stirring reaction is centrifuged, washed, and dried to obtain Prussian blue and analogues containing different metal ions; wherein the washing is performed by washing with deionized water 2 to 3 times and with anhydrous ethanol 2 to 3 times, respectively, and the drying is performed by vacuum drying at 30 to 50°C for 8 to 20 hours.
[0035] In one or more examples of this embodiment, in step S2, the mixed salt is KNO 3 、NaNO 3 and NaNO 2 Composition, the KNO 3 、NaNO 3 and NaNO 2 The mass ratio is 50~55:5~8:35~45.
[0036] In one or more examples of this embodiment, the KNO 3 、NaNO 3 and NaNO 2 The mass ratio is 53:7:40.
[0037] In one or more examples of this embodiment, in step S2, the Prussian blue analogs containing different metal ions are reacted with KNO 3 、NaNO 3 and NaNO 2 The mass ratio is 0.1:50~55:5~8:35~45.
[0038] In one or more examples of this embodiment, the Prussian blue analogs containing different metal ions are mixed with KNO 3 、NaNO 3 and NaNO 2 The mass ratio is 0.1:53:7:40.
[0039] In one or more examples of this embodiment, in step S2, the temperature of the heating treatment is 280-350° C., and the time is 10-30 min.
[0040] In one or more examples of this embodiment, the product after the heating treatment is washed with deionized water to remove mixed salt impurities, and then vacuum dried at 30 to 50° C. for 10 to 24 hours to obtain a high entropy spinel oxide nanomaterial.
[0041] A second typical embodiment of the present invention is a high entropy spinel oxide nanomaterial, which is prepared by the method for preparing high entropy spinel oxide nanomaterial by the molten salt protection method.
[0042] A third typical embodiment of the present invention provides an application of the high entropy spinel oxide nanomaterial in electrolysis of water.
[0043] In one or more embodiments of this embodiment, the three-electrode system used in the electrolysis of water is an electrode coated with the high-entropy spinel oxide nanomaterial described in the second aspect as a working electrode, a platinum electrode as a counter electrode, a Hg / HgO electrode as a reference electrode, 1 mol / L potassium hydroxide as an electrolyte, and a glass electrolytic cell as a reaction device.
[0044] In one or more embodiments of this embodiment, during the electrolysis of water, the current density reaches 10 mA cm -2 When the overpotential of the high entropy spinel oxide nanomaterial is 300-320 mV.
[0045] The present invention can convert Prussian blue analogs (PBAs) into spinel oxide nanomaterials by subjecting them to a molten salt protection method. The molten salt protection method is to heat the reactants after mixing with low-melting-point salts to melt the salts to form a melt, in which the reactants react to generate target products, and sintering of the material during the calcination process can be avoided. The molten salt protection method can increase the content of high-valent ions in nanomaterials and increase the number of active sites, thereby greatly improving the oxygen evolution performance of the material. The synthesized powder has a fine and uniform particle size, which is beneficial to improving the performance of the material, and different molten salts can be selected and the reaction conditions can be controlled, and the structure of the product can be regulated to meet different application requirements. Due to the simple process, the molten salt protection method is suitable for large-scale production and can meet the requirements of industrial applications.
[0046] The present invention will be further described in detail below in conjunction with specific embodiments. It should be noted that the specific embodiments are intended to explain the present invention rather than to limit it.
[0047] Example 1 :This embodiment provides a high entropy spinel oxide nanomaterial and preparation method
[0048] (1) Synthesis of CoNiCuMnZnFe PBA: 1.323 g trisodium citrate (4.5 mmol), 0.5819 g Co(NO3 ) 2 6H 2 O (2.0 mmol), 0.0581 g Ni(NO 3 ) 2 6H 2 O (0.2 mmol), 0.0483 g Cu(NO 3 ) 2 ·3H 2 O (0.2 mmol), 0.0519 g Mn(NO 3 ) 2 ·4H 2 O (0.2 mmol), 0.0595 g Zn(NO 3 ) 2 6H 2 O (0.2 mmol) and 0.0808 g Fe(NO 3 ) 3 9H 2 O (0.2mmol) was dissolved in 25mL water, and solution I was obtained after stirring at room temperature for 1 minute; 0.6647g potassium hexacyanocobaltate (2mmol) was dissolved in 25mL water, stirred for 1 minute, and then added dropwise to solution I to obtain solution II, and a uniform dispersion was obtained after rapid stirring for 30 minutes at a speed of 600rpm / min. The reaction solution was collected by centrifugation, washed with deionized water 3 times and anhydrous ethanol 2 times, and dried in vacuum at 40℃ for 12h to obtain pink CoNiCuMnZnFe PBA powder.
[0049] (2) Synthesis of high entropy spinel oxide nanomaterials: 1.325 g KNO 3 , 0.175 g NaNO 3 and 1.000gNaNO 2 (mass ratio is 53:7:40) and mixed and ground evenly. Then, 0.100g of CoNiCuMnZnFe PBA precursor was added to the mixed salt, and it was transferred to a muffle furnace at a temperature of 300°C and kept at 300°C for 15 minutes. Finally, the porcelain crucible was taken out of the muffle furnace, cooled to room temperature, and the product was washed with deionized water to remove the impurities of the mixed salt, and vacuum dried at 40°C for 12h to obtain a black powder (CoNiCuMnZnFe-O), such as Figure 1 As shown, the XRD spectrum proves the successful preparation of the nanomaterial.
[0050] Experimental Example 2 :This embodiment provides a high entropy spinel oxide nanomaterial and preparation method
[0051] (1) Synthesis of CoNiCuMnZnCr PBA: 1.323 g trisodium citrate (4.5 mmol), 0.5819 g Co(NO 3 ) 2 6H 2 O (2.0 mmol), 0.0581 g Ni(NO 3 ) 2 6H 2 O (0.2 mmol), 0.0483 g Cu(NO 3 ) 2 ·3H 2 O (0.2 mmol), 0.0519 g Mn(NO 3 ) 2 ·4H 2 O (0.2 mmol), 0.0595 g Zn(NO 3 ) 2 6H 2 O (0.2 mmol) and 0.0800 g Cr(NO 3 ) 3 9H 2 O (0.2mmol) was dissolved in 25mL water, and solution I was obtained after stirring at room temperature for 1 minute; 2mmol potassium hexacyanocobaltate was dissolved in 25mL water, stirred for 1 minute, and then added dropwise to solution I to obtain solution II, and a uniform dispersion was obtained after rapid stirring for 30 minutes at a speed of 600rpm / min. The reaction solution was collected by centrifugation, washed with deionized water 3 times and anhydrous ethanol 2 times, and dried in vacuum at 40℃ for 12h to obtain pink CoNiCuMnZnCrPBA powder.
[0052] (2) Synthesis of high entropy spinel oxide nanomaterials: 1.325 g KNO 3 , 0.175 g NaNO 3 and 1.000gNaNO 2 (mass ratio is 53:7:40) and mixed and ground evenly. Then 0.100g CoNiCuMnZnCr PBA precursor was added to the mixed salt, and it was transferred to a muffle furnace at a temperature of 300°C and kept at 300°C for 15 minutes. Finally, the porcelain crucible was taken out of the muffle furnace, cooled to room temperature, and the product was washed with deionized water to remove mixed salt impurities, and vacuum dried at 40°C for 12h to obtain a black powder (CoNiCuMnZnCr-O).
[0053] Experimental Example 3 :This embodiment provides a high entropy spinel oxide nanomaterial and preparation method
[0054] Step 1, Synthesis of CoNiCuMnFeCr PBA: 1.323 g trisodium citrate (4.5 mmol), 0.5819 g Co(NO 3 ) 2 6H 2 O (2.0 mmol), 0.0581 g Ni(NO 3 ) 2 6H 2 O (0.2 mmol), 0.0483 g Cu(NO 3 ) 2 ·3H 2 O (0.2 mmol) and 0.0519 g Mn(NO 3 ) 2 ·4H 2 O (0.2 mmol), 0.0808 g Fe(NO 3 ) 3 9H 2 O (0.2 mmol) and 0.0808 g Cr(NO 3 ) 3 9H 2 O (0.2mmol) was dissolved in 25mL water, stirred at room temperature for 1 minute to obtain solution I; potassium hexacyanocobaltate (2mmol) was dissolved in 25mL water, stirred for 1 minute and then added dropwise to solution I to obtain solution II, which was rapidly stirred for 30 minutes to obtain a uniform dispersion at a speed of 600rpm / min. The reaction solution was collected by centrifugation, washed 3 times with deionized water and 2 times with anhydrous ethanol, and dried in vacuum at 40℃ for 12h to obtain pink CoNiCuMnFeCr PBA powder.
[0055] Step 2: Synthesis of high-entropy spinel oxide nanomaterials: 1.325 g KNO 3 , 0.175 g NaNO 3 and 1.000 g NaNO 2 (mass ratio is 53:7:40) and mixed and ground evenly. Then 0.100g of CoNiCuMnFeCr PBA precursor was added to the mixed salt, and it was transferred to a muffle furnace at a temperature of 300°C and kept at 300°C for 15 minutes. Finally, the porcelain crucible was taken out of the muffle furnace, cooled to room temperature, and the product was washed with deionized water to remove impurities from the mixed salt, and vacuum dried at 40°C for 12h to obtain a black powder (CoNiCuMnFeCr-O).
[0056] Experimental Example 4 :This embodiment provides a high entropy spinel oxide nanomaterial and preparation method
[0057] Step 1, Synthesis of CoNiCuZnFeCr PBA: 1.323 g trisodium citrate (4.5 mmol), 0.5819 g Co(NO 3 ) 2 6H 2 O (2.0 mmol), 0.0581 g Ni(NO 3 ) 2 6H 2 O (0.2 mmol), 0.0483 g Cu(NO 3 ) 2 ·3H 2 O (0.2 mmol) and 0.0595 g Zn(NO 3 ) 2 6H 2 O (0.2 mmol), 0.0808 g Fe(NO 3 ) 3 9H 2 O (0.2 mmol) and 0.0808 g Cr(NO 3 ) 3 9H 2 O (0.2mmol) water, stirred at room temperature for 1 minute to obtain solution I; potassium hexacyanocobaltate (2mmol) was dissolved in 25mL water, stirred for 1 minute and then added dropwise to solution I to obtain solution II, and stirred rapidly for 30 minutes to obtain a uniform dispersion at a speed of 600rpm / min. The reaction solution was collected by centrifugation, washed 3 times with deionized water and 2 times with anhydrous ethanol, and dried in vacuum at 40℃ for 12h to obtain pink CoNiCuZnFeCr PBA powder.
[0058] Step 2: Synthesis of high-entropy spinel oxide nanomaterials: 1.325 g KNO 3 , 0.175 g NaNO 3 and 1.000 g NaNO 2 (mass ratio is 53:7:40) and mixed and ground evenly. Then 0.100g of CoNiCuZnFeCr PBA precursor was added to the mixed salt, and it was transferred to a muffle furnace at a temperature of 300°C and kept at 300°C for 15 minutes. Finally, the porcelain crucible was taken out of the muffle furnace, cooled to room temperature, and the product was washed with deionized water to remove mixed salt impurities, and vacuum dried at 40°C for 12h to obtain a black powder (CoNiCuZnFeCr-O).
[0059] Example 5 :This embodiment provides a high entropy spinel oxide nanomaterial and preparation method
[0060] Step 1, Synthesis of CoNiMnZnFeCr PBA: 1.323 g trisodium citrate (4.5 mmol), 0.5819 g Co(NO 3 ) 2 6H 2 O (2.0 mmol), 0.0581 g Ni(NO 3 ) 2 6H 2 O (0.2 mmol), 0.0519 g Mn(NO 3 ) 2 ·4H 2 O (0.2 mmol) and 0.0595 g Zn(NO 3 ) 2 6H 2 O (0.2 mmol), 0.0808 g Fe(NO 3 ) 3 9H 2 O (0.2 mmol) and 0.0808 g Cr(NO 3 ) 3 9H 2 O (0.2mmol) was dissolved in 25mL water, stirred at room temperature for 1 minute to obtain solution I; potassium hexacyanocobaltate (2mmol) was dissolved in 25mL water, stirred for 1 minute and then added dropwise to solution I to obtain solution II, which was rapidly stirred for 30 minutes to obtain a uniform dispersion at a speed of 600rpm / min. The reaction solution was collected by centrifugation, washed 3 times with deionized water and 2 times with anhydrous ethanol, and dried in vacuum at 40℃ for 12h to obtain pink CoNiMnZnFeCr PBA powder.
[0061] Step 2: Synthesis of high-entropy spinel oxide nanomaterials: 1.325 g KNO 3 , 0.175 g NaNO 3 and 1.000 g NaNO 2 (mass ratio is 53:7:40) and mixed and ground evenly. Then 0.100g of CoNiMnZnFeCr PBA precursor was added to the mixed salt, and it was transferred to a muffle furnace at a temperature of 300°C and kept at 300°C for 15 minutes. Finally, the porcelain crucible was taken out of the muffle furnace, cooled to room temperature, and the product was washed with deionized water to remove impurities from the mixed salt, and vacuum dried at 40°C for 12h to obtain a black powder (CoNiMnZnFeCr-O).
[0062] Example 6 :This embodiment provides a high entropy spinel oxide nanomaterial and preparation method
[0063] (1) Synthesis of CoCuMnZnFeCr PBA: 1.323 g trisodium citrate (4.5 mmol) and 0.5819 g Co(NO 3 ) 2 6H 2 O (2.0 mmol), 0.0483 g Cu(NO 3 ) 2 ·3H 2 O (0.2 mmol), 0.0519 g Mn(NO 3 ) 2 ·4H 2 O (0.2 mmol) and 0.0595 g Zn(NO 3 ) 2 6H 2 O (0.2 mmol), 0.0808 g Fe(NO 3 ) 3 9H 2 O (0.2 mmol) and 0.0808 g Cr(NO 3 ) 3 9H 2 O (0.2mmol) was dissolved in 25mL water, stirred at room temperature for 1 minute to obtain solution I; potassium hexacyanocobaltate (2mmol) was dissolved in 25mL water, stirred for 1 minute and then added dropwise to solution I to obtain solution II, which was rapidly stirred for 30 minutes to obtain a uniform dispersion at a speed of 600rpm / min. The reaction solution was collected by centrifugation, washed 3 times with deionized water and 2 times with anhydrous ethanol, and dried in vacuum at 40℃ for 12h to obtain pink CoCuMnZnFeCr PBA powder.
[0064] (2) Synthesis of high entropy spinel oxide nanomaterials: 1.325 g KNO 3 , 0.175 g NaNO 3 and 1.000gNaNO 2 (mass ratio is 53:7:40) and mixed and ground evenly. Then 0.100g CoCuMnZnFeCr PBA precursor was added to the mixed salt, and it was transferred to a muffle furnace at a temperature of 300°C and kept at 300°C for 15 minutes. Finally, the porcelain crucible was taken out of the muffle furnace, cooled to room temperature, and the product was washed with deionized water to remove mixed salt impurities, and vacuum dried at 40°C for 12h to obtain a black powder (CoCuMnZnFeCr-O).
[0065] Application Example 1 :This test example conducts water electrolysis test on the nanomaterials prepared in Examples 1 to 6
[0066] (1) Weigh 4 mg of the nanomaterial and put it into a 2 mL centrifuge tube. Add 1 mL of a mixed solution of isopropanol and water (volume ratio 1:3), and then add 50 μL of Nafion solution. Ultrasonic for 30 minutes. Take 5 μL (containing 20 μg of the nanomaterial) of the above dispersion and drop-coat it on the surface of the glassy carbon electrode. The diameter of the glassy carbon electrode is 3 mm, and the catalyst loading is 0.285 mg cm -2 . The prepared working electrode coated with the high-entropy spinel oxide nanomaterial is dried at room temperature for 2 hours.
[0067] (2) Adopt a typical three-electrode system to test the electrocatalytic water splitting oxygen evolution performance on a Chenhua electrochemical workstation. Use the electrode coated with the nanomaterial as the working electrode, a platinum electrode as the counter electrode, and a Hg / HgO electrode as the reference electrode. Use 1 mol / L potassium hydroxide as the electrolyte and a glass electrolytic cell as the reaction device.
[0068] (3) Conduct linear sweep voltammetry testing in the three-electrode system. The voltage range is 0.1 - 0.9 V. The initial voltage is 0.1 V, the termination voltage is 0.9 V, the scanning rate is 50 mV / s, the sampling interval is 0.001 V, and the stationary time is 2 s. After data processing and calculation, when the current density reaches 10 mA cm -2 , measure the overpotential of different nanomaterials. The specific values are as Figure 2 shown in Table 1:
[0069] Table 1 Overpotential values (mV) measured in Examples 1 - 6
[0070] Example 1 Example 2 Example 3 Example 4 Example 5 Example 6 310 310 320 300 320 320
[0071] It can be seen from the table data that during the process of electrolyzing water, when the current density reaches 10 mA cm -2 , the overpotential of the high-entropy spinel oxide nanomaterial prepared in the examples of the present invention is 300 - 320 mV. In particular, the overpotential of the CoNiCuMnZnFe spinel oxide nanomaterial is 310 mV, demonstrating its excellent oxygen evolution performance and high OER catalytic activity.
[0072] The above are only the preferred embodiments of the present invention and are not used to limit the present invention. For those skilled in the art, the present invention can have various changes and modifications. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.
Claims
1. A method for preparing high entropy spinel oxide nanomaterials by molten salt protection method, characterized in that: The specific steps include: S1. Mixing aqueous solutions of cobalt salt and other metal salts, and then adding trisodium citrate to obtain solution I; dropping an aqueous solution of potassium hexacyanocobaltate into solution I to obtain solution II, and stirring to react, thereby obtaining Prussian blue and analogs containing different metal ions; S2. Prussian blue analogues containing different metal ions are added to the mixed salt respectively, and high entropy spinel oxide nanomaterials are obtained after heating.
2. The method for preparing high entropy spinel oxide nanomaterials by molten salt protection method according to claim 1, characterized in that: In step S1, the other metal salts are selected from at least five of nickel salts, copper salts, manganese salts, zinc salts, iron salts, and chromium salts.
3. The method for preparing high entropy spinel oxide nanomaterials by molten salt protection method according to claim 1, characterized in that: In step S1, the molar ratio of the cobalt salt to other metal salts is 2:1-1.2; the molar ratio of the cobalt salt to trisodium citrate is 2:4-5; and the molar ratio of the potassium hexacyanocobaltate to the cobalt salt is 1-1.2:
1.
4. The method for preparing high entropy spinel oxide nanomaterials by molten salt protection method according to claim 1, characterized in that: In step S1, the reaction solution obtained after the stirring reaction is centrifuged, washed, and dried to obtain Prussian blue and analogs containing different metal ions; wherein the washing is washing with deionized water 2 to 3 times and washing with anhydrous ethanol 2 to 3 times respectively, and the drying is vacuum drying at 30 to 50° C. for 8 to 20 hours.
5. The method for preparing high entropy spinel oxide nanomaterials by molten salt protection method according to claim 1, characterized in that: In step S2, the mixed salt consists of KNO3, NaNO3 and NaNO2, and the mass ratio of KNO3, NaNO3 and NaNO2 is 50-55:5-8:35-45.
6. The method for preparing high entropy spinel oxide nanomaterials by molten salt protection method according to claim 1, characterized in that: In step S2, the mass ratio of the Prussian blue analogue containing different metal ions to KNO3, NaNO3 and NaNO2 is 0.1:50-55:5-8:35-45.
7. The method for preparing high entropy spinel oxide nanomaterials by molten salt protection method according to claim 1, characterized in that: In step S2, the heating treatment is performed at a temperature of 280 to 350°C and for a time of 10 to 30 minutes.
8. A high entropy spinel oxide nanomaterial, prepared by the method for preparing high entropy spinel oxide nanomaterial by the molten salt protection method according to any one of claims 1 to 7.
9. Use of the high entropy spinel oxide nanomaterial according to claim 8 in electrolyzed water.
10. The use according to claim 9, characterized in that The three-electrode system used in the electrolysis of water is an electrode coated with the high entropy spinel oxide nanomaterial described in the second aspect as a working electrode, a platinum electrode as a counter electrode, a Hg / HgO electrode as a reference electrode, 1 mol / L potassium hydroxide as an electrolyte, and a glass electrolytic cell as a reaction device; Preferably, during the electrolysis of water, the current density reaches 10 mA cm -2 When the overpotential of the high entropy spinel oxide nanomaterial is 300-320 mV.