Preparation method of efficient electrolyzed water anode material

Abstract

The invention discloses a preparation method of an efficient electrolyzed water anode material, and particularly discloses a preparation method of a three-way catalyst, which comprises the following steps: S1, removing organic impurities and an oxide layer on the surface of commercial foamed nickel to obtain treated foamed nickel; s2, carrying out a hydrothermal reaction on the treated foamed nickel in a reaction solution to obtain the three-way catalyst, the reaction liquid contains Fe < 3 + >, Zn < 2 + >, OH <-> and CO3 < 2->; the hydrothermal reaction is carried out at the temperature of 120 DEG C for 12 hours. The method is efficient and low in cost, and the three-way catalyst can be easily obtained in a large area.

Description

Technical Field

[0001] The present invention relates to the field of electrocatalytic water electrolysis, and particularly to a preparation method of an efficient anode material for water electrolysis. Background Art

[0002] Non-renewable high-calorie resources such as minerals and other fossil fuels on the earth were important "drivers" indispensable in production and life in the early years. However, the excessive dependence of countries on the above resources has led to adverse consequences such as environmental warming and extreme weather. In recent years, a large number of researchers have focused on finding a high-calorie and environmentally friendly alternative, such as methanol fuel cells, hydrogen energy, etc. For hydrogen energy, unfortunately, the current main hydrogen production still relies on high-voltage electrolysis of water, which will consume a huge amount of energy. As is well known, water splitting for hydrogen production requires a two-electron reaction kinetics. Earlier, some scholars reported that noble metal-based catalysts, such as platinum, ruthenium, rhodium, iridium, palladium, etc., providing active metal sites can effectively reduce the kinetic barrier of the reaction and promote the hydrogen evolution reaction. However, noble metal materials have limited reserves on the earth and high acquisition costs, making it impossible to achieve large-scale industrial hydrogen production. In recent years, with the development of technology, the emergence of micro-nano structures has greatly promoted the industrialization of hydrogen production, and a large number of hydrogen evolution catalysts with lower reaction kinetic barriers have been extensively explored, and the thermal and kinetic barriers of two-electron hydrogen evolution have gradually been overcome by non-noble metal catalysts. Compared with the hydrogen evolution reaction, the four-electron process of the oxygen evolution reaction is slower, which greatly restricts the efficient preparation of clean energy.

[0003] Currently, researchers have found that noble metal oxides and single-atom materials can be competent for the anodic oxygen evolution reaction in traditional electrochemical processes, but their industrial production will be restricted by limited storage and high costs. A typical solution is to dope graphite carbon into noble metal materials at the expense of product selectivity and energy conversion rate in order to reduce costs. However, the problem of restricting the large-scale industrial production of noble metal-based catalysts has not been fundamentally solved. Therefore, it is necessary to develop a new type of catalyst with low cost, large-scale preparation feasibility, and simple preparation environment to reduce the energy barrier of electrochemical reactions, accelerate the kinetic process, and thus achieve the benefit of efficiently obtaining clean high-calorie energy.

[0004] As previously discussed, single-atom materials are one of the typical models for maximizing the use of active sites in electrochemical reactions, such as Fe / Ni, Co / Ni, Fe / Co, Pt / Ir, Pt / Ru, etc. Their low overpotential and Tafel slope have confirmed their key role in the field of oxygen evolution. However, the stability of single-atom materials is affected by the local cluster effect in the catalytic reaction, and there are also problems such as difficult preparation. In the past few years, two-dimensional materials with a large specific surface area and non-saturated coordinated atom edges, such as graphene, transition metal sulfides, selenides, etc., have shown excellent development prospects in the field of electrocatalysis. However, their high carrier recombination rate has also become an important internal factor restricting catalytic activity.

[0005] Therefore, it is necessary to develop an anode catalyst with a simple preparation process, low cost, and rich active sites (efficient preparation) to promote the green chemical preparation of clean energy. Summary of the Invention

[0006] The present invention aims to solve at least one of the technical problems in the related art to some extent. For this reason, an object of the present invention is to propose a preparation strategy for an efficient electrolytic water anode material with high efficiency, low cost, and easy large-area acquisition. The present invention aims to overcome the practical problems of high cost, low efficiency, and poor stability of nano-catalysts under the harsh environment of multi-stage current changes.

[0007] In the first aspect of the present invention, a preparation method of a ternary catalyst is proposed. According to an embodiment of the present invention, the method includes:

[0008] S1: Remove the organic impurities and oxide layer on the surface of commercial nickel foam to obtain treated nickel foam;

[0009] S2: Perform a hydrothermal reaction on the treated nickel foam in a reaction solution to obtain the ternary catalyst;

[0010] The reaction solution contains Fe 3+ , Zn 2+ , OH−, and CO3 2 −;

[0011] The hydrothermal reaction is carried out at a temperature of 120 °C for 12 hours. This method is efficient, low-cost, and easy to obtain the ternary catalyst in large areas.

[0012] According to an embodiment of the present invention, the above method may further include at least one of the following additional technical features:

[0014] According to an embodiment of the present invention, in step S1, the organic impurities on the surface of commercial nickel foam are removed by washing the surface of commercial nickel foam with absolute ethanol.

[0015] According to an embodiment of the present invention, in step S1, the oxide layer on the surface of commercial nickel foam is removed by washing with dilute hydrochloric acid.

[0016] According to an embodiment of the present invention, the reaction solution is prepared in the following manner:

[0017] A1) Perform a first mixing process on Fe(NO3)3·9H2O, Zn(NO3)2·6H2O, and water to obtain a metal source preparation solution;

[0018] A2) Perform a second mixing process on the metal source preparation solution and urea to obtain the reaction solution.

[0019] According to an embodiment of the present invention, the first mixing process is carried out in the following manner:

[0020] Fully dissolve Fe(NO3)3·9H2O in water and immediately perform slight stirring to obtain a light yellow to yellow transparent solution, and place Zn(NO3)2·6H2O in the light yellow to yellow transparent solution and stir vigorously for 30 min to obtain the metal source preparation solution.

[0021] According to an embodiment of the present invention, the second mixing process is carried out by stirring vigorously for 30 min.

[0022] According to an embodiment of the present invention, the molar ratio of Fe(NO3)3·9H2O to Zn(NO3)2·6H2O is (0.1 - 1):1, such as 0.1:1, 0.3:1, 0.5:1, 0.75:1, or 1:1, etc.

[0023] According to an embodiment of the present invention, the rotation speed of the slight stirring is 200 revolutions per minute and the time is 30 s.

[0024] According to an embodiment of the present invention, the rotation speed of the vigorous stirring is 900 revolutions per minute and the time is 30 min.

[0025] According to an embodiment of the present invention, the hydrothermal reaction is carried out in a self - pressurized Teflon reactor.

[0026] According to an embodiment of the present invention, the sample obtained after the hydrothermal reaction is further washed with water and absolute ethanol.

[0027] According to an embodiment of the present invention, the ternary catalyst is nickel - doped zinc - iron layered double hydroxide.

[0028] In another aspect of the present invention, the present invention also provides a ternary catalyst. According to an embodiment of the present invention, the ternary catalyst is prepared by the method described above.

[0029] In yet another aspect of the present invention, the present invention also provides a method for preparing an efficient electrolyzed water anode material, comprising the following steps:

[0030] a. Removing organic impurities on the surface of commercial nickel foam: Cut the commercial nickel foam self-supporting electrode, soak it in a beaker filled with ethanol, then place it in an ultrasonic cleaner for oscillation, and then add deionized water. Repeat the above ultrasonic step. At this time, the organic impurities on the surface of the nickel foam have been completely removed;

[0031] b. Removing the oxide layer on the surface of commercial nickel foam: Immerse the nickel foam with a clean surface in dilute hydrochloric acid, perform ultrasonic cleaning, then change the solution to deionized water and continue ultrasonic cleaning. After vacuum drying, the oxides generated by the nickel foam in the air have been removed at this time;

[0032] c. Vigorously stirring to obtain a bimetallic source reaction solution: Weigh different molar amounts of Fe(NO3)3·9H2O and dissolve them separately in deionized water and immediately stir slightly to obtain a light yellow to yellow transparent solution. Weigh a certain amount of Zn(NO3)2·6H2O and place it in the above solution and stir vigorously to obtain a metal source preparation solution without precipitation;

[0033] d. Providing anions and an alkaline environment: Add a certain amount of urea to the metal source preparation solution. Utilize the hydrolysis characteristics of urea by heat to provide the hydroxide and carbonate required for material growth, which results in the flaky characteristics of the electrolyzed water electrode. Then stir vigorously for 30 min to obtain a uniform reaction solution;

[0034] e. Encapsulating and providing a hydrothermal environment: Place the nickel foam after impurity removal treatment and the reaction solution together in a self-generated pressure Teflon reaction kettle and provide the required growth environment. The obtained sample is washed with deionized water and absolute ethanol and vacuum dried, and the efficient electrolyzed water ternary catalyst of the present invention can be easily obtained safely and on a large scale through a single-step hydrothermal reaction.

[0035] According to the embodiments of the present invention, the molar ratios of iron(III) nitrate nonahydrate to zinc nitrate hexahydrate with different molar masses are 0.1:1, 0.3:1, 0.5:1, 0.75:1, and 1:1 respectively.

[0036] According to the embodiments of the present invention, the immediate gentle stirring is controlled at a rotation speed of 200 revolutions per minute and a time of 30 s; the vigorous stirring speed is 900 revolutions per minute and the time is 30 min; the microscopic morphology of the obtained electrolyzed water electrode is flaky.

[0037] According to the embodiments of the present invention, the efficient electrolyzed water ternary catalyst is nickel-doped zinc-iron layered double hydroxide; the nickel element is the contribution of the nickel foam in the reaction.

[0038] According to an embodiment of the present invention, a preparation strategy for an efficient electrolytic water anode material is disclosed. This strategy includes: using deionized water and absolute ethanol to remove organic impurities and oxide layers on the surface of commercial nickel foam. Further, vigorously stirring ferric nitrate nonahydrate and zinc nitrate hexahydrate in a mixed state with a certain molar ratio to obtain a bimetallic source reaction solution. Adding a certain amount of ammonium fluoride and urea to the mixed metal precursor solution and stirring. Subsequently, encapsulating the solution system and providing a high-temperature environment. After vacuum drying, the efficient electrolytic water anode material in the present invention can be obtained. The obtained target has stable physical and chemical properties and adjustable performance. The preparation process is safe, pollution-free, low-cost, and easy to obtain.

[0039] According to an embodiment of the present invention, compared with the reported technologies, the present invention has at least one of the following excellent features:

[0040] 1) The raw materials used in the present invention are all easy to obtain, low-cost, and the obtained catalyst exhibits excellent oxygen evolution performance.

[0041] 2) The preparation strategy can in-situ prepare ternary layered double hydroxides with a large specific surface area on the surface of commercial nickel foam in only one step. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] The above and / or additional aspects and advantages of the present invention will become apparent and easy to understand from the description of the embodiments in conjunction with the following drawings, where:

[0043] Figure 1 is the in-situ preparation flow chart of the efficient electrolytic water anode material constructed in the embodiment;

[0044] Figure 2 is the scanning electron microscope image of Ni@ZnFe LDH-0.2 in-situ constructed in Example 1. The model of the scanning electron microscope used for shooting is JEOLS-4800 produced in Japan, and the scanning voltage is set to 10 KeV;

[0045] Figure 3 is the scanning electron microscope image of Ni@ZnFe LDH-0.6 in-situ constructed in Example 2;

[0046] Figure 4 is the scanning electron microscope image of Ni@ZnFe LDH-1.0 in-situ constructed in Example 3;

[0047] Figure 5 is the scanning electron microscope image of Ni@ZnFe LDH-1.5 in-situ constructed in Example 4;

[0048] Figure 6 is the scanning electron microscope image of Ni@ZnFe LDH-2.0 in-situ constructed in Example 5;

[0049] Figure 7 Polarization curves of Ni@ZnFe LDH constructed in situ in Examples 1-5;

[0050] Figure 8 Tafel slope diagrams of Ni@ZnFe LDH constructed in situ in Examples 1-5;

[0051] Figure 9 Nyquist diagrams of Ni@ZnFe LDH constructed in situ in Examples 1-5;

[0052] Figure 10 Cyclic voltammograms of Ni@ZnFe LDH-1.5 in Example 4 at different sweep rates in the non-Faradaic region;

[0053] Figure 11 Cyclic voltammograms of Ni@ZnFe LDH constructed in situ in Examples 1-5;

[0054] Figure 12 Diagrams of 12-hour stability test, front and back scanning electron microscope images, and polarization curves of Ni@ZnFe LDH-1.5 in Example 4;

[0055] Figure 13 X-ray diffraction diagrams of Ni@ZnFe LDH-1.5 before and after 12-hour stability test in Example 4. The X-ray diffractometer is produced by Bruker, model D8 Advance, and uses Cu as the X-ray source with a wavelength of 0.154 nm;

[0056] Figure 14 Raman spectra of Ni@ZnFe LDH-1.5 before and after 12-hour stability test in Example 4. The confocal Raman spectrometer model is LabRAM HR Evolution, and the used laser wavelength and intensity are 532 nm and 5.36 mW respectively. Detailed implementation manners

[0057] The embodiments described below by referring to the accompanying drawings are exemplary and are intended to explain the present invention, and should not be construed as limiting the present invention.

[0058] In addition, the terms "first" and "second" are only used for descriptive purposes and should not be construed as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. Thus, the features defined with "first" and "second" may explicitly or implicitly include at least one of such features. In the description of the present invention, the meaning of "a plurality" is at least two, such as two, three, etc., unless otherwise specifically defined.

[0059] The present invention will be described below with reference to specific embodiments. It should be noted that these embodiments are merely descriptive and do not limit the present invention in any way.

[0060] Example 1

[0061] Preparation stage:

[0062] (1) Cut a commercial nickel foam self-supporting electrode and immerse it in a beaker containing 50 mL of anhydrous ethanol with a purity of 99% for 5 min, and then place it in an ultrasonic cleaner and shake for 15 min. Then add 50 mL of deionized water (18.25 MΩ / cm) prepared by a Millipore system, and repeat the above ultrasonic step. At this time, the organic impurities on the surface of the nickel foam have been removed.

[0063] (2) Immerse the nickel foam with a clean surface in 6 mol / L dilute hydrochloric acid prepared from 38% concentrated hydrochloric acid, and ultrasonically clean for 15 min. Then change the solution to deionized water and continue ultrasonic cleaning for 15 min. After vacuum drying, the oxides generated by the nickel foam in the air have been removed.

[0064] (3) Weigh 0.08 g (0.2 mmol) of Fe(NO3)3·9H2O and fully dissolve it in 70 ml of deionized water, and immediately stir at a speed of 200 revolutions per minute for 30 s to obtain a light yellow to yellow transparent solution. Weigh 0.595 g (2 mmol) of Zn(NO3)2·6H2O and place it in the above solution, and stir at a speed of 900 revolutions per minute for 30 min to obtain a metal source preparation solution without precipitation.

[0065] (4) Add 0.6 g (10 mmol) of urea to the metal source preparation solution. Utilize the hydrolysis characteristics of urea when heated to provide the hydroxide and carbonate required for material growth, which results in the flaky characteristics of the electrolytic water electrode. Then stir vigorously at a speed of 900 revolutions per minute for 30 min to obtain a uniform reaction solution.

[0066] (5) Place the nickel foam after impurity removal treatment and the reaction solution together in a 100 mL self - pressurized Teflon reaction kettle, and provide a growth environment of 120 °C for 12 h. The obtained sample is washed with deionized water and anhydrous ethanol and vacuum dried to obtain Ni@ZnFe LDH.

[0067] Testing stage:

[0068] (1) Use a scanning electron microscope to photograph the Ni@ZnFe LDH - 0.2 obtained in Example 1 to obtain its scanning electron microscope image. As Figure 2 shown, Ni@ZnFe LDH - 0.2 has a flaky morphology and no obvious aggregation effect.

[0069] (2) Using the electrode, HgHgO, and Pt wire obtained in Example 1 as the working electrode, reference electrode, and counter electrode respectively, the polarization curve, Tafel slope, charge transfer resistance, and double-layer capacitance of Ni@ZnFe LDH-0.2 obtained in Example 1 were calculated and characterized using a CHI 760e (Shanghai Chenhua) electrochemical workstation. As Figures 7 - 9 shown by the black block diagram lines in Figure 11, it can be seen that the electrocatalytic performance, kinetic process, and double-layer capacitance value of this electrode do not exhibit excellent characteristics.

[0070] Example 2

[0071] Preparation stage:

[0072] (1) Cut a commercial nickel foam self-supporting electrode and immerse it in a beaker containing 50 mL of anhydrous ethanol with a purity of 99% for 5 min, and then place it in an ultrasonic cleaner and shake for 15 min. Subsequently, add 50 mL of deionized water (18.25 MΩ / cm) prepared by a Millipore system and repeat the above ultrasonic step. At this time, the organic impurities on the surface of the nickel foam have been removed.

[0073] (2) Immerse the nickel foam with a clean surface in 6 mol / L dilute hydrochloric acid prepared from 38% concentrated hydrochloric acid, ultrasonically clean for 15 min, and then replace the solution with deionized water and continue ultrasonic cleaning for 15 min. After vacuum drying, the oxides generated by the nickel foam in the air have been removed.

[0074] (3) Weigh 0.24 g (0.6 mmol) of Fe(NO3)3·9H2O and fully dissolve it in 70 ml of deionized water, and immediately stir it at a speed of 200 revolutions per minute for 30 s to obtain a light yellow to yellow transparent solution. Weigh 0.595 g (2 mmol) of Zn(NO3)2·6H2O and place it in the above solution, and stir it at a speed of 900 revolutions per minute for 30 min to obtain a metal source preparation solution without precipitation.

[0075] (4) Add 0.6 g (10 mmol) of urea to the metal source preparation solution. Utilize the hydrolysis characteristics of urea by heating to provide the hydroxide and carbonate required for material growth, which results in the flaky characteristics of the electrolyzed water electrode. Then stir vigorously at a speed of 900 revolutions per minute for 30 min to obtain a uniform reaction solution.

[0076] (5) Place the nickel foam after impurity removal treatment and the reaction solution together in a 100 mL self-pressure Teflon reactor, and provide a growth environment of 120 °C and 12 h. The obtained sample was washed with deionized water and anhydrous ethanol and vacuum dried to obtain Ni@ZnFe LDH.

[0077] Testing stage:

[0078] (1) Use a scanning electron microscope to photograph Ni@ZnFe LDH-0.6 obtained in Example 2 to obtain its scanning electron microscope image, as Figure 3 shown. Ni@ZnFe LDH-0.6 has a flaky morphology and no obvious aggregation effect.

[0079] (2) Use the electrode, HgHgO, and Pt wire obtained in Example 2 as the working electrode, reference electrode, and counter electrode respectively, and use a CHI 760e (Shanghai Chenhua) electrochemical workstation to calculate and characterize the polarization curve, Tafel slope, charge transfer resistance, and double-layer capacitance of Ni@ZnFe LDH-0.6 obtained in Example 2. As Figures 7 - 9 shown by the black triangular plot line in Figure 11, it can be seen that the electrocatalytic performance, kinetic process, and double-layer capacitance value of this electrode do not exhibit excellent characteristics.

[0080] Example 3

[0081] Preparation stage:

[0082] (1) Cut a commercial nickel foam self-supporting electrode and immerse it in a beaker containing 50 mL of anhydrous ethanol with a purity of 99% for 5 min, and then place it in an ultrasonic cleaner and shake it for 15 min. Then add 50 mL of deionized water (18.25 MΩ / cm) prepared by a Millipore system and repeat the above ultrasonic step. At this time, the organic impurities on the surface of the nickel foam have been removed.

[0083] (2) Immerse the nickel foam with a clean surface in 6 mol / L dilute hydrochloric acid prepared from 38% concentrated hydrochloric acid, ultrasonically clean it for 15 min, and then replace the solution with deionized water and continue ultrasonic cleaning for 15 min. After vacuum drying, the oxides generated by the nickel foam in the air have been removed.

[0084] (3) Weigh 0.40 g (1.0 mmol) of Fe(NO3)3·9H2O and fully dissolve it in 70 ml of deionized water, and immediately stir it at a speed of 200 revolutions per minute for 30 s to obtain a light yellow to yellow transparent solution. Weigh 0.595 g (2 mmol) of Zn(NO3)2·6H2O and place it in the above solution and stir it at a speed of 900 revolutions per minute for 30 min to obtain a metal source preparation solution without precipitation.

[0085] (4) Add 0.6 g (10 mmol) of urea to the metal source preparation solution. Utilize the hydrolysis characteristics of urea by heat to provide the hydroxide and carbonate required for material growth, which results in the flaky characteristics of the electrolyzed water electrode. Then stir vigorously at a speed of 900 revolutions per minute for 30 min to obtain a homogeneous reaction solution.

[0086] (V) Place the nickel foam after impurity removal treatment and the reaction solution together in a 100 mL self - pressurized Teflon reactor, and provide a growth environment of 120 °C for 12 h. The obtained sample is washed with deionized water and absolute ethanol and dried under vacuum to obtain Ni@ZnFe LDH.

[0087] Testing stage:

[0088] (I) Use a scanning electron microscope to photograph the Ni@ZnFe LDH - 1.0 obtained in Example 3 to obtain its scanning electron micrograph. As Figure 4 shown, Ni@ZnFe LDH - 1.0 has a flaky morphology and no obvious aggregation effect.

[0089] (II) Use the electrode, HgHgO, and Pt wire obtained in Example 3 as the working electrode, reference electrode, and counter electrode respectively. Use a CHI 760e (Shanghai Chenhua) electrochemical workstation to calculate and characterize the polarization curve, Tafel slope, charge transfer resistance, and double - layer capacitance of the Ni@ZnFe LDH - 1.0 obtained in Example 3. As Figures 7 - 9 and the black diamond - shaped graph line in Figure 11 shows, it can be seen that the electrocatalytic performance, kinetic process, and double - layer capacitance value of this electrode do not reach the most excellent performance.

[0090] Example 4

[0091] Preparation stage:

[0092] (I) Cut a commercial nickel foam self - supporting electrode and immerse it in a beaker containing 50 mL of absolute ethanol with a purity of 99% for 5 min, and then place it in an ultrasonic cleaner and shake for 15 min. Then add 50 mL of deionized water (18.25 MΩ / cm) prepared by a Millipore system and repeat the above ultrasonic step. At this time, the organic impurities on the surface of the nickel foam have been removed.

[0093] (II) Immerse the nickel foam with a clean surface in 6 mol / L dilute hydrochloric acid prepared from 38% concentrated hydrochloric acid, ultrasonically clean for 15 min, and then change the solution to deionized water and continue ultrasonic cleaning for 15 min. After vacuum drying, the oxides generated by the nickel foam in the air have been removed.

[0094] (III) Weigh 0.61 g (1.5 mmol) of Fe(NO3)3·9H2O and fully dissolve it in 70 ml of deionized water and immediately stir at a speed of 200 revolutions per minute for 30 s to obtain a light yellow to yellow transparent solution. Weigh 0.595 g (2 mmol) of Zn(NO3)2·6H2O and place it in the above solution and stir at a speed of 900 revolutions per minute for 30 min to obtain a metal source preparation solution without precipitation.

[0095] (4) Add 0.6 g (10 mmol) of urea to the prepared solution containing the metal source. Utilize the hydrolysis characteristics of urea when heated to provide the hydroxide and carbonate required for material growth, which results in the flaky characteristics of the electrolyzed water electrode. Subsequently, stir vigorously at a speed of 900 revolutions per minute for 30 min to obtain a homogeneous reaction solution.

[0096] (5) Place the foam nickel after impurity removal treatment and the reaction solution together in a 100 mL self - pressurized Teflon reactor, and provide a growth environment of 120 °C for 12 h. The obtained sample is washed with deionized water and absolute ethanol and dried in vacuum to obtain Ni@ZnFe LDH.

[0097] Testing stage:

[0098] (1) Use a scanning electron microscope to photograph Ni@ZnFe LDH - 1.5 obtained in Example 4 to obtain its scanning electron microscope image, as Figure 5 shown, Ni@ZnFe LDH - 1.5 has a flaky morphology and no obvious aggregation effect.

[0099] (2) Use the electrode, HgHgO, and Pt wire obtained in Example 4 as the working electrode, reference electrode, and counter electrode respectively. Use a CHI 760e (Shanghai Chenhua) electrochemical workstation to calculate and characterize the polarization curve, Tafel slope, charge transfer resistance, cyclic voltammetry curve, double - layer capacitance, stability, and the polarization curve, scanning electron microscope, X - ray diffraction pattern, and Raman spectrum before and after stability testing of Ni@ZnFe LDH - 1.5 obtained in Example 4. As Figures 7 - 14 shown, compared with other examples, it can be seen that the electrocatalytic performance, kinetic process, and double - layer capacitance value of this electrode have reached the most excellent state. In addition, its stability still shows a stable electrode state under a 12 - h non - constant current test. The effectiveness characterization after stability testing (such as scanning electron microscope, X - ray diffraction pattern, Raman spectrum, polarization curve, etc.) also shows no obvious performance change, peak position shift, or submergence, which means that the chemical properties of the electrode are stable in a non - stable test application environment.

[0100] Example 5

[0101] Preparation stage:

[0102] (1) Cut a commercial foam nickel self - structured electrode, place it in a beaker containing 50 mL of anhydrous ethanol with a purity of 99% and soak for 5 min, then place it in an ultrasonic cleaner and shake for 15 min. Subsequently, add 50 mL of deionized water (18.25 MΩ / cm) prepared by a Millipore system, and repeat the above ultrasonic step. At this time, the organic impurities on the surface of the foam nickel have been removed.

[0103] (2) Immerse the nickel foam with a clean surface in 6 mol / L dilute hydrochloric acid prepared from 38% concentrated hydrochloric acid, and ultrasonically clean it for 15 min. Subsequently, replace the solution with deionized water and continue ultrasonic cleaning for 15 min. After vacuum drying, the oxides generated by the nickel foam in the air have been removed at this time.

[0104] (3) Weigh 0.81 g (2.0 mmol) of Fe(NO3)3·9H2O and fully dissolve it in 70 ml of deionized water, and immediately stir it at a speed of 200 revolutions per minute for 30 s to obtain a light yellow to yellow transparent solution. Weigh 0.595 g (2 mmol) of Zn(NO3)2·6H2O and place it in the above solution, and stir it at a speed of 900 revolutions per minute for 30 min to obtain a metal source preparation solution without precipitation.

[0105] (4) Add 0.6 g (10 mmol) of urea to the metal source preparation solution. Utilize the characteristic of urea hydrolysis by heat to provide the hydroxide and carbonate required for material growth, which results in the flaky characteristics of the electrolyzed water electrode. Subsequently, stir vigorously at a speed of 900 revolutions per minute for 30 min to obtain a homogeneous reaction solution.

[0106] (5) Place the nickel foam after impurity removal treatment and the reaction solution together in a 100 mL self - pressurized Teflon reaction kettle, and provide a growth environment of 120 °C and 12 h. The obtained sample is washed with deionized water and absolute ethanol and vacuum dried to obtain Ni@ZnFe LDH.

[0107] Testing stage:

[0108] (1) Use a scanning electron microscope to photograph the Ni@ZnFe LDH - 2.0 obtained in Example 5 to obtain its scanning electron microscope image. As Figure 6 shown, Ni@ZnFe LDH - 2.0 has a flaky morphology and is not accompanied by an obvious polymerization effect.

[0109] (2) Use the electrode obtained in Example 6, HgHgO, and Pt wire as the working electrode, reference electrode, and counter electrode respectively, and use a CHI 760e (Shanghai Chenhua) electrochemical workstation to calculate and characterize the polarization curve, Tafel slope, charge transfer resistance, and double - layer capacitance of the Ni@ZnFe LDH - 2.0 obtained in Example 6. As Figures 7 - 9 shown in the black star - shaped graph line in 11, it can be seen that the electrocatalytic performance, kinetic process, and double - layer capacitance value of this electrode do not reach the most excellent performance.

[0110] In summary, the strategy described in the embodiments of this specification enables the single-step, simple, and controllable preparation of large-area flaky ternary Ni@ZnFe LDH with excellent electrochemical performance. It not only demonstrates the controllability of the morphology but also exhibits excellent performance stability and structural stability during long-term stability tests.

[0111] It should be noted that the above embodiments are only illustrative languages for clarifying or helping to understand the present invention, rather than limiting the protection scope of the present invention. Therefore, those of ordinary skill in the art should understand that any modifications, equivalent replacements made to the embodiments of the present invention without departing from the spirit of the present invention should be included within the scope of the present claims.

[0112] In the description of this specification, the descriptions referring to terms such as "one embodiment", "some embodiments", "example", "specific example", or "some examples" etc. mean that the specific features, structures, materials, or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic expressions of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described can be combined in a suitable manner in any one or more embodiments or examples. In addition, without contradiction, those skilled in the art can combine and combine the different embodiments or examples described in this specification and the features of different embodiments or examples.

[0113] Although the embodiments of the present invention have been shown and described above, it can be understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those of ordinary skill in the art can make changes, modifications, replacements, and variations to the above embodiments within the scope of the present invention.

Claims

1. A preparation method of a three-way catalyst, characterized in that, Comprising: S1: Removing organic impurities and oxide layer on the surface of commercial nickel foam to obtain treated nickel foam; S2: Subjecting the treated nickel foam to hydrothermal reaction in a reaction solution to obtain the ternary catalyst; The reaction solution contains Fe 3+ , Zn 2+ , OH⁻ and CO₃ 2 ⁻; The hydrothermal reaction is carried out at a temperature of 120 °C for 12 hours.

2. The method according to claim 1, wherein In step S1, the organic impurities on the surface of commercial nickel foam are removed by washing the surface of commercial nickel foam with absolute ethanol.

3. The method according to claim 1, characterized in that, In step S1, the oxide layer on the surface of commercial nickel foam is removed by washing with dilute hydrochloric acid.

4. The method according to claim 1, wherein The reaction solution is prepared by the following method: A1) Performing a first mixing treatment on Fe(NO3)3·9H2O, Zn(NO3)2·6H2O and water to obtain a metal source preparation solution; A2) Performing a second mixing treatment on the metal source preparation solution and urea to obtain the reaction solution.

5. The method according to claim 4, characterized in that The first mixing treatment is carried out by the following method: Fully dissolving Fe(NO3)3·9H2O in water and immediately performing gentle stirring to obtain a light yellow to yellow transparent solution, and placing Zn(NO3)2·6H2O in the light yellow to yellow transparent solution and vigorously stirring for 30 min to obtain the metal source preparation solution.

6. The method according to claim 4, wherein The second mixing treatment is carried out by vigorously stirring for 30 min.

7. The method according to claim 4, characterized in that The molar ratio of Fe(NO3)3·9H2O to Zn(NO3)2·6H2O is (0.1 - 1):

1.

8. The method according to claim 5 or 6, characterized in that, The rotation speed of the gentle stirring is 200 revolutions per minute and the time is 30 s; Optionally, the rotation speed of the vigorous stirring is 900 revolutions per minute and the time is 30 min.

9. The method according to claim 1, wherein The hydrothermal reaction is carried out in a self - pressurized Teflon reactor; Optionally, the sample obtained after the hydrothermal reaction further includes washing with water and absolute ethanol; Optionally, the ternary catalyst is nickel - doped zinc - iron layered double hydroxide.

10. A three-way catalyst, characterized in that, The ternary catalyst is prepared by the method according to any one of claims 1 - 9.

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