High-entropy perovskite material and preparation method and application thereof

Abstract

The invention relates to a high-entropy perovskite material and a preparation method and application thereof, the chemical formula of the high-entropy perovskite material is ABO3, the A-site element is La element, and the B-site element is selected from 5-10 transition metal elements; the high-entropy perovskite material has a two-dimensional Tailing structure, nano-particles are arranged in a cross-linking manner, and gaps are formed among the particles. Compared with the prior art, the two-dimensional Turing structure high-entropy perovskite material is endowed with excellent electro-catalytic water decomposition hydrogen production performance due to unique morphology and components, is adaptive to fluctuation power of clean energy such as wind energy and solar energy, and has a wide industrial application prospect.

Description

Technical Field

[0001] The present invention relates to the technical field of high entropy catalysts, and in particular to a high entropy perovskite material and a preparation method and application thereof. Background Art

[0002] Due to its zero carbon emissions and high energy density, hydrogen is the most promising clean energy to replace traditional fuels. In view of this, producing green hydrogen through electrocatalytic water splitting is an effective way to achieve the goal of carbon neutrality. The anode oxygen evolution reaction (OER) is an important half-reaction in electrocatalytic water splitting. However, due to the slow kinetic reaction of the electron transfer process in the OER reaction, it has become the main reason limiting the overall efficiency of electrocatalytic water splitting. Therefore, the development of OER catalysts with both high activity and high stability is the main way to reduce the consumption of the water electrolysis system and achieve efficient hydrogen production.

[0003] High-entropy oxides (HEOs) refer to oxide materials formed by combining five or more elements. Due to the strong interactions between multi-metal elements, HEOs usually exhibit flexible and adjustable metal site coordination environment and oxidation state, which greatly optimizes the adsorption of OER intermediates and thus enhances OER catalytic activity. However, in actual industrial electrocatalytic water splitting systems, the frequent start and stop of equipment, the reduction effect of reverse current, and the corrosion of strong alkaline electrolytes all pose new challenges to catalyst development and design. Therefore, it is necessary to provide an OER catalyst that can effectively enhance the adaptability and stability under fluctuating power while ensuring OER activity. Summary of the Invention

[0004] The purpose of the present invention is to provide a high-entropy perovskite material and its preparation method and application, which exhibits high OER activity, power fluctuation adaptability and anti-reverse current characteristics.

[0005] The object of the present invention can be achieved by the following technical solution: a high entropy perovskite material, the chemical formula of which is ABO3, wherein the A-site element is La, and the B-site element is selected from 5 to 10 transition metal elements;

[0006] The high-entropy perovskite material has a two-dimensional Turing structure, with nanoparticles arranged cross-linked with each other and gaps between the particles.

[0007] Preferably, the B-site elements are selected from five or more of Mn, Fe, Co, Ni, Cu, Zn, Cr, Mo, W, and V.

[0008] Further preferably, the B-site elements are selected from five of Mn, Fe, Co, Ni, Cu, Zn, Cr, Mo, W, and V.

[0009] More preferably, the B-site element is Mn, Fe, Co, Ni, or Cu.

[0010] Preferably, the molar ratio of each transition metal element at position B is (1.1-0.9):1.

[0011] More preferably, the molar ratio of the transition metal elements at position B is 1:1.

[0012] Preferably, the molar ratio of the La element to the total amount of the B-site transition metal elements is (1.1-0.9):1.

[0013] Further preferably, the molar ratio of the La element to the total amount of the B-site transition metal elements is 1:1.

[0014] Preferably, the chemical formula of the high entropy perovskite material is La(Mn 0.2 Fe 0.2 Co 0.2 Ni 0.2 Cu 0.2 )O3.

[0015] Preferably, the high entropy perovskite material has a lateral size of 5-10 μm and a thickness of 70-100 nm.

[0016] Preferably, the constituent units of the high entropy perovskite material are coral-like particles.

[0017] Further preferably, the coral-like particles are cross-linked end to end and are regularly distributed along a plane in a periodic manner to form a porous network structure.

[0018] More preferably, there is a gap of 20-300 nm between the coral-like particles.

[0019] More preferably, there is a gap of 20-100 nm between the coral-like particles.

[0020] Preferably, the high entropy perovskite material has multiple groups of different crystal planes, and different lattice fringes on both sides of the grain boundary.

[0021] A method for preparing the above-mentioned high entropy perovskite material comprises the following steps:

[0022] Add the metal ion nitrate corresponding to the A-site and B-site elements to the chelating agent solution, stir evenly, add ammonia water and adjust the solution pH to 9-11, increase the stirring temperature, and continue stirring until the metal organic gel is formed;

[0023] Drying the metal organic gel to form a xerogel, and heating and calcining the xerogel to form the high entropy perovskite material;

[0024] During the heating calcination process, the heating rate is 8-10°C / min, the temperature is raised to 750-850°C and maintained at this temperature for 2-3 hours;

[0025] The chelating agent is an organic small molecule containing both amino and carboxyl functional groups.

[0026] Preferably, during the temperature-raising calcination process, the temperature is raised to 800° C. and maintained at this temperature for 2-3 hours.

[0027] Preferably, the metal ion nitrates corresponding to the B-site elements are first added to the chelating agent solution, and then the metal ion nitrates corresponding to the A-site elements are added to the chelating agent solution.

[0028] More preferably, the metal ion nitrates corresponding to Mn, Fe, Co, Ni, and Cu are first added to the chelating agent solution in sequence, and then the metal ion nitrate corresponding to La is added to the chelating agent solution.

[0029] Preferably, the chelating agent is glycine, glycine dipeptide or β-alanine.

[0030] More preferably, the chelating agent is glycine.

[0031] Preferably, the molar ratio of the chelating agent to the total amount of metal ions corresponding to the A-site and B-site elements is (1-10):1.

[0032] Further preferably, the molar ratio of the chelating agent to the total amount of metal ions corresponding to the A-site and B-site elements is (3-5):1.

[0033] In the present invention, the material obtained with a molar ratio between (3-5):1 has the best OER activity and is more conducive to the formation of Turing structure.

[0034] More preferably, the molar ratio of the chelating agent to the total amount of metal ions corresponding to the A-site and B-site elements is 4:1.

[0035] Preferably, the chelating agent solution is a chelating agent aqueous solution, and the chelating agent is added into deionized water and dispersed uniformly to form a chelating agent solution.

[0036] Preferably, the method for preparing the high entropy perovskite material specifically comprises the following steps:

[0037] Add the metal ion nitrate corresponding to the A-site and B-site elements to the chelating agent solution and stir at 40-50°C for 1-3 hours. Then, add ammonia water and adjust the solution pH to 9-11. Then, increase the stirring temperature to 85-95°C and continue stirring until the metal organic gel is formed.

[0038] The metal organic gel is placed in an oven and dried at 100-120° C. to form a dry gel. The dry gel is placed in a muffle furnace and calcined at a high temperature to form a flaky solid, which is the high entropy perovskite material.

[0039] A catalyst comprises the above-mentioned high-entropy perovskite material.

[0040] An electrode comprises a conductive substrate and the above catalyst supported on the conductive substrate.

[0041] An electrolysis device comprises the above-mentioned electrode.

[0042] Preferably, the electrolysis device comprises a working electrode, a counter electrode, a diaphragm and an electrolyte, and the working electrode is the electrode.

[0043] A method for assembling the above electrolysis device into three series water-splitting electrolyzers comprises the following steps:

[0044] A catalyst-coated working electrode is placed in the anode chamber, nickel foam is placed in the cathode chamber, a polyphenylene sulfide (PPS) membrane is sandwiched between the working electrode and the counter electrode, and three identical sets of the above-assembled electrolyzers are connected in series and fixed with bolts to form a three-series water-splitting electrolyzer;

[0045] A 6M KOH solution was placed in a strong alkali-resistant container, and an electrolyte flow rate controller was used to drive the electrolyte to flow into the cathode chamber and the anode chamber respectively.

[0046] A method for performing power fluctuation testing and start-stop testing using the three water-splitting electrolyzers connected in series comprises the following steps:

[0047] Power fluctuation test at 10mA / cm 2 , 100mA / cm 2 and 250mA / cm 2 The current density was alternately switched, each time lasting 100 s, and the cycle was repeated 100 times;

[0048] Power ramp test at 1mA / cm 2 and 250mA / cm 2 The current density was alternately switched, each time lasting 100 s, and the cycle was repeated 200 times;

[0049] Start-stop test at 0mA / cm 2 and 250mA / cm 2 The current density was alternately switched at 200 s each time and the cycle was repeated 40 times.

[0050] An application of the above-mentioned high-entropy perovskite material is to use the high-entropy perovskite material as an anode oxygen evolution reaction catalyst in an electrocatalytic water decomposition system.

[0051] Preferably, the high entropy perovskite material is loaded on a conductive substrate as an anode oxygen evolution reaction catalyst to obtain a working electrode, and the working electrode is placed in the anode chamber of an alkaline water splitting electrolyzer (AWE) as an anode for an electrocatalytic water splitting system.

[0052] Further preferably, the conductive substrate comprises nickel foam or carbon paper.

[0053] More preferably, the nickel foam has a thickness of 1-3 mm.

[0054] Further preferably, the alkaline water splitting electrolyzer includes an anode chamber, a cathode chamber and a diaphragm, the anode chamber is provided with an anode and an anode electrolyte, the cathode chamber is provided with a cathode and a cathode electrolyte, the diaphragm is used to separate the cathode electrolyte in the cathode chamber from the anode electrolyte in the anode chamber, the anode is the working electrode, and the cathode is nickel foam.

[0055] More preferably, the flow rate of the cathode electrolyte and the anode electrolyte is 25-35 mL / min.

[0056] More preferably, the cathode electrolyte and the anode electrolyte are KOH solution, NaOH solution, KCl solution or NaCl solution.

[0057] Preferably, the cathode electrolyte and the anode electrolyte are 1-6M KOH solutions.

[0058] More preferably, the membrane is a proton exchange membrane or an ion exchange membrane.

[0059] Preferably, the separator is a polyphenylene sulfide (PPS) membrane.

[0060] Further preferably, the internal components of the alkaline water splitting electrolytic cell are made of strong alkali-resistant materials.

[0061] More preferably, the end plates of the alkaline water splitting electrolytic cell are made of stainless steel.

[0062] More preferably, the bipolar plates of the alkaline water splitting electrolyzer are made of metallic nickel.

[0063] More preferably, the anode chamber and cathode chamber of the alkaline water splitting electrolyzer are made of polytetrafluoroethylene.

[0064] An application of the above-mentioned high entropy perovskite material in a simulated industrial electrocatalytic water splitting environment.

[0065] Compared with the prior art, the present invention has the following beneficial effects:

[0066] 1. The two-dimensional Turing-structured high-entropy perovskite material of the present invention can enhance the adsorption of intermediate species after applying an electric potential, and at the same time become more flexible, which helps to enhance the ability of the water-splitting electrode to adapt to power fluctuations and frequent starts and stops.

[0067] 2. The two-dimensional Turing structure high entropy perovskite material of the present invention is used as a catalyst for electrocatalytic water decomposition, showing high OER activity, adaptability to power fluctuations and resistance to reverse current.

[0068] 3. The two-dimensional Turing structure high-entropy perovskite material of the present invention can be used to prepare high-quality OER anode catalysts and three-series water splitting electrolyzer anodes, which have lower overpotential, higher stability and stronger adaptability to fluctuating power compared to conventional nickel foam electrodes.

[0069] 4. The two-dimensional Turing-structured high-entropy perovskite material and the assembled electrolytic cell involved in the present invention can operate stably in strong alkaline and hot alkaline electrolyte conditions and possess high corrosion resistance. On the one hand, the B-position transition metal element in the perovskite material has good dissolution resistance under strong alkaline and high potential conditions, and the high entropy effect enhances this stability. On the other hand, the polyphenylene sulfide diaphragm selected for the electrolytic cell is resistant to strong alkaline and hot alkaline, and the internal components of the electrolytic cell are also made of strong alkaline-resistant stainless steel, nickel metal, or polytetrafluoroethylene.

[0070] 5. The present invention ensures the formation of a more uniform perovskite precursor organogel by regulating the type of chelating agent, the element selection and ratio design of the A-site metal and the B-site metal during the catalyst synthesis process.

[0071] 6. The present invention ensures that the metal organic gel expands at a more stable rate by coordinating the heating rate and the calcination temperature. At the same time, it ensures that the CO2 release rate during the combustion of the organic gel is more stable, thereby avoiding the destruction of the two-dimensional morphology due to excessive expansion or excessive CO2 release.

[0072] 7. The two-dimensional Turing-structured high-entropy perovskite catalyst contained in the present invention exhibited stability for more than 220 hours in a three-series water-splitting electrolyzer (6 M KOH electrolyte at 60°C), maintained a high peak potential stability after 40 cyclic start-stop tests, and maintained a response rate of less than 30 seconds after 200 1000-fold power surges.

[0073] 8. The present invention only requires one chelating agent, the material synthesis cycle is short, the operation is simple, and the repeatability is high.

[0074] 9. The unique morphology and composition of the two-dimensional Turing structure high-entropy perovskite material of the present invention give it excellent electrocatalytic water decomposition and hydrogen production performance, as well as adaptability to fluctuating power of clean energy such as wind energy and solar energy, and has broad industrial application prospects. BRIEF DESCRIPTION OF THE DRAWINGS

[0075] Figure 1 These are scanning electron microscope images of HEOs-Gly at scales of 5 μm and 1 μm, respectively.

[0076] Figure 2 These are side-view scanning electron micrographs of HEOs-Gly at scales of 5 μm and 1 μm.

[0077] Figure 3 In the figure, A is a transmission electron microscope image of Turing particles of HEOs-Gly with a scale of 100 nm, and B is a high-resolution lattice fringes with a scale of 10 nm.

[0078] Figure 4 In the figure, A and B are transmission electron micrographs of another Turing particle of HEOs-Gly with a scale of 200 nm and high-resolution lattice fringes with a scale of 5 nm at different positions.

[0079] Figure 5 Figure 1 shows the dissipative electrochemical quartz crystal microbalance (EQCM-D) test results for HEOs-Gly. Figure A shows the resonant frequency (f) of a quartz crystal chip sensor coated with HEOs-Gly powder, collected during cyclic voltammetry (CV) testing. Figure B shows the dissipation factor (D) of the quartz crystal chip sensor, collected during CV testing.

[0080] Figure 6 Schematic diagram of the three-series water-splitting electrolyzer used in the electrocatalytic water-splitting test.

[0081] Figure 7 Figure 2 is the stability diagram of the HEOs-Gly electrode obtained by testing using three series water splitting electrolyzers.

[0082] The test duration is 220h and the test current is 250mA / cm 2 , the test conditions are 60℃ and the electrolyte is 6MKOH.

[0083] Figure 8 This is a start-stop test diagram of the HEOs-Gly electrode obtained by testing using three series water-splitting electrolyzers.

[0084] Among them, the shutdown current density is 0mA / cm 2 , the operating current density is 250mA / cm 2 , each time period is 200s, the test condition is 60℃, and the electrolyte is 6M KOH.

[0085] Figure 9This is a power step fluctuation test diagram of the HEOs-Gly electrode obtained by testing using three series water splitting electrolyzers. Among them, the current density is 10mA / cm 2 , 100mA / cm 2 and 250mA / cm 2 , each time period is 100s, the test condition is 60℃, and the electrolyte is 6M KOH.

[0086] Figure 10 This is a power fluctuation test chart of the HEOs-Gly electrode obtained by testing using three series water splitting electrolyzers. The lowest current density is 1mA / cm 2 , the maximum current density is 250mA / cm 2 , each time period is 100s, the test condition is 60℃, and the electrolyte is 6M KOH.

[0087] Figure 11 These are scanning electron micrographs of HEOs-Ala at scales of 5 μm and 1 μm.

[0088] Figure 12 These are scanning electron micrographs of HEOs-Cyc at scales of 5 μm and 1 μm.

[0089] Figure 13 These are scanning electron microscope images of HEOs-Eth at scales of 5 μm and 1 μm.

[0090] Figure 14 These are scanning electron micrographs of HEOs-Pla at scales of 5 μm and 1 μm.

[0091] Figure 15 Comparison of linear voltammetric scan curves of five catalysts with different morphologies.

[0092] Figure 16 These are scanning electron micrographs of HEOs-Gly+CA at scales of 5 μm and 1 μm.

[0093] Figure 17 These are scanning electron micrographs of HEOs-EDTA+CA at scales of 5 μm and 1 μm.

[0094] Figure 18 These are scanning electron micrographs of HEOs-EDTA+Gly at scales of 5 μm and 1 μm.

[0095] Reference numerals: anode end plate 110 , anode electrolyte inlet 111 , anode plate 120 , anode plate terminal tab 121 , anode gas chamber 130 , diaphragm 131 , cathode gas chamber 132 , bipolar plate 140 , cathode plate 150 , cathode plate terminal tab 151 , cathode end plate 160 , cathode electrolyte inlet 161 . DETAILED DESCRIPTION

[0096] The present invention is described in detail below with reference to the accompanying drawings and specific embodiments. This embodiment is implemented based on the technical solution of the present invention, and provides a detailed implementation method and specific operation process, but the protection scope of the present invention is not limited to the following embodiments.

[0097] In a first aspect of the present invention, a novel two-dimensional Turing structure high-entropy perovskite material is provided, wherein the two-dimensional Turing structure high-entropy perovskite material comprises a lanthanum (La) element at the A position and 5-10 transition metal elements at the B position.

[0098] In some embodiments of the present invention, the molar ratio of the La element at the A site to all transition metal elements at the B site is between 1.1:1 and 0.9:1, and the most preferred molar ratio is 1:1.

[0099] In some embodiments of the present invention, the B-site transition metal element is Mn, Fe, Co, Ni, Cu, Zn, Cr, Mo, W, or V.

[0100] In some preferred embodiments of the present invention, the transition metal is Mn, Fe, Co, Ni, or Cu, and the preferred molar ratio of each transition metal element is 1:1.

[0101] In some embodiments of the present invention, the molar ratio of chelating agent to total metal ions is between 1:1 and 10:1, with the most preferred molar ratio being 4:1.

[0102] In other embodiments of the present invention, the metal ion chelating agent can be glycine, glycine dipeptide or β-alanine, and the most preferred chelating agent is glycine.

[0103] In a second aspect of the present application, a method for preparing the two-dimensional Turing structure high entropy perovskite material according to the first aspect of the present invention is provided, the preparation method comprising the following steps:

[0104] Add the chelating agent to deionized water and disperse evenly to form a chelating agent solution. Add the metal ion nitrates sequentially to the above solution and stir at 45°C for 1-3 hours. Subsequently, add ammonia water and adjust the solution pH to 9-11. Then, increase the stirring temperature to 85-95°C and continue stirring until the metal organic gel is formed.

[0105] The metal-organic gel formed by the above method is placed in an oven and dried at 100-120°C to form a xerogel. The xerogel is then placed in a muffle furnace and heated at a rate of 8-10°C / min to 800°C and maintained at this temperature for 2-3 hours. The resulting flaky solid is a two-dimensional Turing-structured high-entropy perovskite material.

[0106] The third aspect of the present invention provides a catalyst comprising the above-mentioned two-dimensional Turing structure high entropy perovskite material.

[0107] A fourth aspect of the present invention provides an electrode comprising a conductive substrate and the aforementioned catalyst supported on the conductive substrate, wherein the conductive substrate is nickel foam (1-3 mm thick) or carbon paper, with 1 mm thick nickel foam being a preferred substrate.

[0108] According to a fifth aspect of the present invention, an electrolysis device is provided, comprising the aforementioned electrode.

[0109] In some embodiments of the present invention, the electrolysis device includes an anode, a cathode, a diaphragm and an electrolyte, and the anode is the aforementioned electrode.

[0110] In some embodiments of the present invention, the electrolysis device is an alkaline water splitting electrolyzer (AWE), and the electrolysis flow cell device includes an anode chamber, a cathode chamber, a diaphragm, an anode chamber electrolyte flow rate controller, and a cathode chamber electrolyte flow rate controller. The anode chamber is provided with an anode and an electrolyte, the anode being the aforementioned electrode, and the cathode chamber is provided with a cathode and an electrolyte, and the diaphragm is used to separate the electrolyte in the cathode chamber from the electrolyte in the anode chamber. The anode chamber electrolyte flow rate controller and the cathode chamber electrolyte flow rate controller are used to control the flow rates of the anolyte in the anode chamber and the catholyte in the cathode chamber, respectively.

[0111] In some embodiments of the invention, the flow rates of the catholyte and the anolyte are both 30 mL / min.

[0112] In some embodiments of the present invention, the electrolysis device comprises a working electrode, a counter electrode, a diaphragm, and an electrolyte, wherein the working electrode is the aforementioned electrode. The counter electrode includes, but is not limited to, a platinum electrode, a nickel foam electrode, and a Raney nickel electrode. The electrolyte includes, but is not limited to, a KOH solution, a NaOH solution, a KCl solution, and a NaCl solution. The diaphragm includes, but is not limited to, a proton exchange membrane and an ion exchange membrane. The most preferred electrolyte is KOH, the most preferred counter electrode is a nickel foam electrode, and the most preferred membrane is a PPS membrane.

[0113] In some embodiments of the present invention, the electrolyte is a 1-6 M KOH solution.

[0114] In a sixth aspect of the present invention, a method is provided for assembling the above-mentioned electrolysis device into three water-splitting electrolyzers connected in series and performing electrocatalytic water splitting to produce hydrogen.

[0115] In some embodiments of the present invention, a catalyst-coated working electrode is placed in the anode compartment, nickel foam is placed in the cathode compartment, and a PPS membrane is sandwiched between the working electrode and the counter electrode. Three identical sets of these assembled electrolyzers are connected in series and secured with bolts to form a triple-series water-splitting electrolyzer.

[0116] In some embodiments of the present invention, a 6M KOH solution is placed in a strong alkali-resistant container, and an electrolyte flow rate controller is used to drive the electrolyte to flow into the cathode chamber and the anode chamber respectively.

[0117] In some embodiments of the present invention, the stability test is performed at 250 mA / cm 2 This method is used to test the catalytic stability of two-dimensional Turing structure high entropy perovskite materials in a three-series water splitting electrolyzer.

[0118] In some embodiments of the present invention, the start-stop test is performed at 0 mA / cm 2 and 250mA / cm 2 The method was used to test the catalytic stability of two-dimensional Turing-structured high-entropy perovskite materials during repeated start-stop cycles, with each cycle lasting 200 seconds and 40 cycles.

[0119] In some embodiments of the present invention, the power fluctuation test is performed at 10 mA / cm 2 , 100mA / cm 2 and 250mA / cm 2 The current density was alternately switched at 100 s for 100 cycles. This method was used to test the catalytic stability of two-dimensional Turing-structured high-entropy perovskite materials under staged current density steps.

[0120] In some embodiments of the present invention, the power fluctuation test is performed at 1 mA / cm 2 and 250mA / cm 2 The method was used to test the catalytic stability of two-dimensional Turing-structured high-entropy perovskite materials under large power fluctuations.

[0121] The following describes it in detail with reference to specific embodiments.

[0122] Unless otherwise specified, the reagents, methods, instruments and equipment used in the present invention are conventional reagents, methods, instruments and equipment in the art. Unless otherwise specified, the reagents and materials used in the following examples are commercially available.

[0123] Example 1

[0124] This embodiment provides a high-entropy perovskite material with a two-dimensional Turing structure. The preparation method of the high-entropy perovskite material is as follows:

[0125] HEOs-Gly was synthesized by sol-gel combined with one-step calcination method. The specific process is as follows:

[0126] Place 20 mL of deionized water in a beaker and dissolve 54 mg of solid glycine in the deionized water. Adjust the heating plate temperature to 45°C. Add 0.6 mL of 0.03 M solutions of Mn(NO3)2, Fe(NO3)3, Co(NO3)2, Ni(NO3)2, and Cu(NO3)2, along with 3 mL of 0.03 M La(NO3)3, to the chelating agent solution while stirring vigorously for 1 hour. Then, add aqueous ammonia dropwise to adjust the pH to 10. Raise the stirring temperature to 92°C and continue stirring until the metal-organic gel forms.

[0127] The metal-organic gel formed by the above method was placed in an oven and dried at 120°C for 12 hours to form a xerogel. The xerogel was then placed in a muffle furnace and heated to 800°C at a rate of 10°C / min and maintained at this temperature for 2 hours. The resulting flaky solid is a two-dimensional Turing-structured high-entropy perovskite material (HEOs-Gly).

[0128] Characterization results:

[0129] Figure 1 These are scanning electron micrographs of HEOs-Gly synthesized in Example 1. The scale bars in A and B are 5 μm and 1 μm, respectively. As can be seen in Figure A, HEOs-Gly exhibits a typical flake-like morphology with lateral dimensions of 5-10 μm. Figure B shows that HEOs-Gly exhibits a typical Turing structure, with cross-linked nanoparticles and interstitial spaces between the particles.

[0130] Figure 2 This is a side-view scanning electron micrograph of the HEOs-Gly synthesized in Example 1. The scale bar is 1 μm. As can be seen from the figure, the HEOs-Gly is approximately 70 nm thick and has a two-dimensional structure.

[0131] Figure 3 Figures 1 and 2 show transmission electron micrographs and high-resolution lattice fringes of HEOs-Gly synthesized in Example 1. Figure A shows a transmission electron micrograph of a Turing particle of HEOs-Gly at a scale of 100 nm. This image shows that the constituent units of HEOs-Gly are coral-like particles. Figure B shows high-resolution lattice fringes at the grain boundaries of HEOs-Gly. The lattice fringes correspond to (211) and (110), respectively, corresponding to the crystal planes of the perovskite structure.

[0132] Figure 4 This is a transmission electron micrograph of another position of the HEOs-Gly synthesized in Example 1, along with its high-resolution lattice fringes. The scale for transmission electron micrographs A and B is 200 nm, while the scale for the high-resolution lattice fringes is 5 nm. As can be seen from the figure, the (200), (111), (211), and (110) crystal planes are distributed at the grain boundaries, corresponding to the perovskite structure.

[0133] Figure 5 These are the test results of the dissipative electrochemical quartz crystal microbalance (EQCM-D) of the HEOs-Gly synthesized in Example 1. Figure A shows the resonant frequency (f) of the quartz crystal chip sensor coated with HEOs-Gly powder as collected during the cyclic voltammetry (CV) test. The overall mass of HEOs-Gly increased after CV, confirming the reconstruction of the catalyst at a certain potential and the accelerated adsorption behavior of intermediates in the OER process. Figure B shows the dissipation factor (D) of the quartz crystal chip sensor and the results collected during the CV test. By applying an electric potential to HEOs-Gly, the catalyst becomes more flexible, and this flexibility helps to enhance the ability of the water-splitting electrode to adapt to power fluctuations and frequent starts and stops.

[0134] Performance test of three series water splitting electrolyzers:

[0135] The performance of HEOs-Gly electrode sheets was tested using three series water splitting electrolyzers. Figure 6As shown. The three-series water-splitting electrolyzer includes an anode terminal plate 110, an anode plate 120, and an anode gas chamber 130. The anode plate 120 separates the anode terminal plate 110 from the anode gas chamber 130 and also supports the nickel foam electrode. The anode gas chamber 130 and the cathode gas chamber 132 are separated by a diaphragm 131, which also serves to separate the fluid and gas between the anode and cathode, so that only ion exchange occurs between the anode and cathode. The diaphragm is made of PPS material and can withstand strong alkali (up to 30 wt.%) and electrolytes around 100°C. The bipolar plate 140 separates the cathode gas chamber 132 on one side from the anode gas chamber 130 on the other side, so that the hydrogen evolution reaction and the oxygen evolution reaction occur separately on both sides of the bipolar plate without affecting each other. Similarly, the cathode terminal plate 160 and the rightmost cathode gas chamber 132 are separated by the cathode plate 150, which also serves to support the nickel foam. The anode plate terminal piece 121 is connected to the working electrode of the electrochemical workstation (Chenhua CHI760E), and the cathode plate terminal piece 151 is connected to the counter electrode and reference electrode of the electrochemical workstation, together forming a dual-electrode system to supply power to the electrolytic cell. The anolyte is introduced through the anode chamber electrolyte flow rate controller (Longer, Halma plc), enters from the anolyte inlet 111, and exits from the anolyte outlet. Similarly, the cathode electrolyte is introduced through the cathode electrolyte flow rate controller, enters from the cathode electrolyte inlet 161, and exits from the cathode electrolyte outlet. Both the cathode and the anolyte flow in from bottom to top, which is convenient for eliminating the influence of bubbles in the electrolyte.

[0136] The HEOs-Gly provided in Example 1 was selected as the anode catalyst on the working electrode to perform a performance test of a three-series water splitting electrolyzer.

[0137] The stability test results of HEOs-Gly electrode are as follows Figure 7 As shown in the figure, the test conditions are 60℃ and the electrolyte KOH concentration is 6mol / L. The test found that the HEOs-Gly anode electrode showed excellent stability and was able to 2 The catalytic activity was stable for 220 h at a current density of 1.5 Å, with a decay rate of approximately 4.3% in the first 100 h and 8.3% after 220 h. The excellent stability of HEOs-Gly is attributed to the adsorption of active species and the reconstruction of active sites after the application of potential.

[0138] The start-stop test results of HEOs-Gly electrode are as follows Figure 8 As shown, the test conditions are 60℃ and the electrolyte KOH concentration is 6mol / L. By setting 0mA / cm 2 and 250mA / cm 2The current was switched back and forth between the start and stop phases of the electrolyzer during industrial operation, with each phase lasting 200 seconds. The test found that the HEOs-Gly electrode was able to start up quickly after shutdown and reach potential stability within 20-30 seconds. After 40 start-stop cycles, the HEOs-Gly electrode still maintained a high rate of increase. The excellent start-stop adaptability of HEOs-Gly is due to its ability to resist reverse current, which is enhanced by the catalyst's flexibility after the application of the potential.

[0139] The power fluctuation test of HEOs-Gly electrode is as follows Figure 9 As shown, the test conditions are 60℃ and the electrolyte KOH concentration is 6mol / L. 2 , 100mA / cm 2 and 250mA / cm 2 The researchers switched between three current densities, each lasting 100 seconds, to simulate the start-up and shutdown conditions of an electrolyzer in industrial operation. The tests revealed that the HEOs-Gly electrode maintained high stability and a rapid ramp-up rate under step-by-step current density changes, particularly at high current densities. The enhanced flexibility of the HEOs-Gly electrode upon application of a potential and its abundant active sites optimize the adsorption behavior of intermediates during the OER process.

[0140] The power ramp test of HEOs-Gly electrode is as follows Figure 10 As shown, the test conditions are 60℃, the electrolyte KOH concentration is 6mol / L, and the current density is 1mA / cm 2 and 250mA / cm 2 The test found that the HEOs-Gly electrode could quickly maintain stability under a 1000-fold power surge, with a ramp-up time of about 20 seconds, and still maintain a relatively fast ramp-up rate after 200 cycles.

[0141] Example 2

[0142] This embodiment provides a Turing structure high entropy perovskite material (HEOs-Ala), which is different from the embodiment 1 in that: Figure 11 As shown, the material has a thick sheet-like morphology with a pore size of approximately 100-150 nm. The preparation method differs from Example 1 in that 78 mg of β-alanine is used as a chelating agent instead of glycine, and the resulting morphology also has a Turing structure. OER testing shows that HEOs-Ala has a low OER overpotential, making it an ideal water splitting electrocatalyst.

[0143] Example 3

[0144] This embodiment provides a Turing structure high entropy perovskite material (HEOs-Cyc), which is different from the embodiment 1 in that: Figure 12As shown, the material has a thick, flake-like morphology with pore sizes of approximately 100-300 nm. The preparation method differs from that of Example 1 in that 97 mg of glycine dipeptide is used as a chelating agent instead of glycine, and the resulting morphology also exhibits a Turing structure. OER testing shows that HEOs-Cyc has a low OER overpotential, making it an ideal water-splitting electrocatalyst.

[0145] Comparative Example 1

[0146] This comparative example provides a non-Turing structure high entropy perovskite material (HEOs-Eth), which is different from Examples 1-3 in that: Figure 13 As shown in the figure, the material does not have a sheet structure, but a block structure. The difference between the preparation method and Example 1 is that ethylamine is used as a chelating agent in an amount equimolar to that in Example 1 instead of glycine. SEM tests show that HEOs-Eth is in a block stacking state, does not have a porous structure, and its constituent units are closely packed irregular particles. OER tests show that HEOs-Eth has a high OER overpotential and poor water decomposition performance.

[0147] Comparative Example 2

[0148] This comparative example provides a non-Turing structure high entropy perovskite material (HEOs-Pla), which is different from Examples 1-3 in that: Figure 14 As shown in the figure, the material does not have a sheet structure, but a block structure. The difference between the preparation method and Example 1 is that propionic acid is used as a chelating agent instead of glycine in an amount equimolar to that in Example 1. SEM tests show that HEOs-Pla is in a block stacking state, with only some mesopores present, and the constituent units are irregular square particles. OER tests show that HEOs-Pla has a high OER overpotential and poor water decomposition performance.

[0149] The linear voltammetric scanning curves of Examples 1-3 and Comparative Examples 1-2 are as follows: Figure 15 As shown in the figure, it can be seen that under the same potential, compared with comparative examples 1-2, the materials of examples 1-3 have faster reaction rates and higher catalytic activities.

[0150] Comparative Example 3

[0151] This comparative example provides a non-Turing structure high entropy perovskite material (HEOs-Gly+CA), which is different from Examples 1-3 in that: Figure 16 As shown, the material does not have a sheet-like structure, but rather a bulk structure. The preparation method differs from that of Example 1 in that an equimolar mixture of glycine and citric acid is used as a chelating agent. When citric acid, which has similar metal chelating properties, is introduced, it competes with glycine, hindering the formation of a stable, uniform metal-organic gel and, consequently, a single-phase, uniform, two-dimensional high-entropy perovskite oxide.

[0152] Comparative Example 4

[0153] This comparative example provides a non-Turing structure high entropy perovskite material (HEOs-EDTA+CA), which is different from Examples 1-3 in that: Figure 17 As shown, the material does not have a sheet-like structure, but rather a block structure. The preparation method differs from that of Example 1 in that an equimolar mixture of ethylenediaminetetraacetic acid and citric acid is used as a chelating agent. When citric acid and ethylenediaminetetraacetic acid, which have similar metal chelating properties, are used together as chelating agents, they compete with metal ions, hindering the formation of a stable, uniform metal organic gel and a single-phase, uniform, two-dimensional high-entropy perovskite oxide.

[0154] Comparative Example 5

[0155] This comparative example provides a non-Turing structure high entropy perovskite material (HEOs-EDTA+Gly), which is different from Examples 1-3 in that: Figure 18 As shown, the material does not have a sheet structure, but a block structure, and the internal component units are not uniformly ordered Turing nanoparticles. The preparation method differs from that of Example 1 in that an equimolar mixture of ethylenediaminetetraacetic acid and glycine is used as a chelating agent. When glycine and ethylenediaminetetraacetic acid, which have the same metal chelating properties, are used together as chelating agents, they will produce a competitive reaction with the metal ions, which is not conducive to the formation of a stable and uniform metal organic gel, and is not conducive to the formation of a single-phase, uniform two-dimensional Turing high-entropy perovskite oxide.

[0156] The novel two-dimensional Turing-structured high-entropy perovskite material provided by this invention exhibits a typical two-dimensional Turing morphology, composed of interlaced Turing nanoparticles. Upon application of an electric potential, the surface of the Turing-structured high-entropy perovskite material undergoes surface reconstruction, improving the adsorption of intermediate species and enhancing the catalyst's flexibility. The unique morphology of the novel two-dimensional Turing-structured high-entropy perovskite material imparts excellent electrocatalytic water splitting performance, adaptability, and stability under fluctuating power conditions, promising broad industrial applications.

[0157] The above description of the embodiments is intended to facilitate understanding and use of the invention by those skilled in the art. It will be apparent that those skilled in the art can readily make various modifications to these embodiments and apply the general principles described herein to other embodiments without requiring inventive effort. Therefore, the present invention is not limited to the above-described embodiments. Improvements and modifications made by those skilled in the art based on the disclosure of the present invention, without departing from the scope of the present invention, should be within the scope of protection of the present invention.

Claims

1. A high entropy perovskite material, characterized in that: The chemical formula is ABO3, where the A-site element is La and the B-site element is selected from 5 to 10 transition metal elements; The high-entropy perovskite material has a two-dimensional Turing structure, with nanoparticles arranged cross-linked with each other and gaps between the particles.

2. The high entropy perovskite material according to claim 1, characterized in that The B-site elements are selected from five or more of Mn, Fe, Co, Ni, Cu, Zn, Cr, Mo, W, and V; The molar ratio of the La element to the total amount of the B-site transition metal elements is (1.1-0.9):

1.

3. The high entropy perovskite material according to claim 2, characterized in that The B-site elements are Mn, Fe, Co, Ni, and Cu; The molar ratio of each transition metal element in position B is (1.1-0.9):

1.

4. The high entropy perovskite material according to claim 1, characterized in that The high entropy perovskite material has a lateral size of 5-10 μm and a thickness of 70-100 nm.

5. The high entropy perovskite material according to claim 1, characterized in that The high entropy perovskite material has multiple groups of different crystal planes, and different lattice stripes on both sides of the grain boundary.

6. A method for preparing the high entropy perovskite material according to any one of claims 1 to 5, characterized in that: The following steps are involved: Add the metal ion nitrate corresponding to the A-site and B-site elements to the chelating agent solution, stir evenly, add ammonia water and adjust the solution pH to 9-11, increase the stirring temperature, and continue stirring until the metal organic gel is formed; Drying the metal organic gel to form a xerogel, and heating and calcining the xerogel to form the high entropy perovskite material; During the heating calcination process, the heating rate is 8-10°C / min, the temperature is raised to 750-850°C and maintained at this temperature for 2-3 hours; The chelating agent is an organic small molecule containing both amino and carboxyl functional groups.

7. The method for preparing a high entropy perovskite material according to claim 6, wherein: The chelating agent is glycine, glycine dipeptide or β-alanine; The molar ratio of the chelating agent to the total amount of metal ions corresponding to the A-site and B-site elements is (1-10):

1.

8. The method for preparing a high entropy perovskite material according to claim 6, wherein: The specific steps include: Add the metal ion nitrate corresponding to the A-site and B-site elements to the chelating agent solution and stir at 40-50°C for 1-3 hours. Then, add ammonia water and adjust the solution pH to 9-11. Then, increase the stirring temperature to 85-95°C and continue stirring until the metal organic gel is formed. The metal organic gel is dried at 100-120° C. to form a dry gel, and the dry gel is heated and calcined to form the high entropy perovskite material.

9. A use of the high entropy perovskite material according to any one of claims 1 to 5, characterized in that: The high entropy perovskite material is used as an anode oxygen evolution reaction catalyst in an electrocatalytic water decomposition system.

10. The use of the high entropy perovskite material according to claim 9, characterized in that: The high entropy perovskite material is loaded on a conductive substrate as an anode oxygen evolution reaction catalyst to obtain a working electrode, and the working electrode is placed in the anode chamber of an alkaline water splitting electrolyzer as an anode for an electrocatalytic water splitting system.

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