Electrocatalytic material as well as preparation and application thereof

Abstract

The invention provides an electro-catalytic material as well as preparation and application thereof, and particularly relates to an electro-catalytic material capable of improving the oxygen evolution reaction performance in electrolyzed water, the active components of the electro-catalytic material comprise NiO and La2O3, and the molar ratio of Ni to La is (2-10): 1; the structure is a load type structure in which sphere-like nanoparticles composed of NiO-La2O3 composite nanosheets are loaded on the surface of foamed nickel, the loading capacity of the electrocatalytic material is 0.012-0.018 g / cm < 2 >, and the electrocatalytic material has the characteristics of strong interaction among components and uniform wrapping on a foamed nickel skeleton, and belongs to the field of preparation of electrochemical catalytic materials. The preparation method has the advantages that the electro-catalysis material is simple in preparation process, mild in condition and low in cost, the material can effectively reduce the overpotential of oxygen evolution reaction, the current density of 10mA cm <-2 > can be reached only by 198mV, the charge transfer resistance is only 2.38 ohm, and the electro-catalysis material can continuously and stably work for 200 hours in a strong alkali environment.

Description

Technical Field:

[0001] The present invention belongs to the field of preparation of electrocatalytic materials, and relates to a composite electrocatalytic material (NiO-La2O3 / NF) of transition metal oxide coupled with rare earth metal oxide that can be used for catalyzing the oxygen evolution reaction (OER), and its preparation and application. This material has strong interaction between components and can effectively accelerate the kinetic performance of the oxygen evolution reaction. Background Art:

[0002] In today's world, human clothing, food, housing, and transportation are all closely linked to energy supply and consumption. Without the energy industry, there would be no modern civilization. However, with the continuous consumption of fossil fuels, the problem of energy crisis has become increasingly prominent. Traditional fossil energy is unclean energy. While meeting the vast majority of the energy needs of human society, it also discharges a large amount of wastewater, waste gas, and waste residue into nature, causing a series of global environmental problems. As a green, high-density, and renewable energy carrier, hydrogen energy has received extensive attention, and hydrogen energy has thus become an indispensable secondary energy form. Hydrogen has been widely regarded as an energy carrier with development potential, but the main form of hydrogen in nature is compounds. Therefore, it is imperative to develop efficient and sustainable hydrogen production technologies.

[0003] Artificial hydrogen production technologies mainly include biological hydrogen production, water photolysis hydrogen production, fossil fuel reforming hydrogen production, and electrolytic water hydrogen production, etc. Due to the low efficiency of biological hydrogen production and water photolysis hydrogen production and their large susceptibility to the external environment, the most commonly used hydrogen production method in today's world's actual production practice is fossil fuel reforming. The hydrogen produced by this method accounts for more than 90% of the global production. However, it inevitably produces greenhouse gas carbon dioxide and acidic gas sulfur dioxide, etc. during the reaction process, which runs counter to the goal of developing new clean energy. Compared with other hydrogen production technologies, electrolytic water hydrogen production is considered a green and efficient method because its raw materials are extensive, the gases generated by the reaction are only hydrogen and oxygen, and it can convert electrical energy that is not easily stored into hydrogen energy that is easily stored. It is the most promising sustainable hydrogen production technology.

[0004] The electrolysis of water reaction consists of the hydrogen evolution reaction (HER) occurring at the cathode and the oxygen evolution reaction (OER) occurring at the anode. Compared with HER, the OER occurring at the anode is a more complex process, requiring 4 electron transfers and catalytic kinetic retardation, which limits the overall efficiency of the water decomposition reaction, resulting in the need for a potential higher than 1.23 V to drive the reaction. Solving this problem usually requires the use of highly active catalysts to achieve efficient water decomposition reactions. Currently, the main catalysts for the OER reaction are noble metal Ir-based or Ru-based materials, such as IrO2 and RuO2. Li et al. (ACS Nano, 2023, 18(1): 1214-1225) prepared α-RuO2 / NiO supported on nickel foam through processes such as hydrothermal-calcination-etching-calcination. Experiments have shown that the amorphous / crystalline structure allows the introduction of a large number of oxygen vacancies, thereby improving the conductivity of the catalyst, adjusting the d-band center, optimizing the adsorption and desorption of intermediates, and achieving excellent overall water decomposition reaction kinetics. Only 1.75 V is required to reach a current density of 100 mA cm -2 −2. However, the price of metal Ru is relatively expensive. Therefore, the development of efficient, abundant, and inexpensive non-precious metal catalysts for OER is one of the current themes in renewable energy research.

[0005] Research has shown that catalysts represented by transition metals such as Fe, Co, and Ni exhibit great potential in the field of water electrolysis. Due to the abundant reserves of Ni in the earth's surface, the cost of nickel-based materials is relatively low. Yang et al. (Small, 2021, 17(32): 2101727) used carbon cloth as the substrate and obtained NiO / CeO2 NW@CC by one-step hydrothermal method and then calcining the hydrothermally obtained product in a tube furnace. Only an overpotential of 330 mV is required to reach a current density of 50 mA cm -2 −2. The results show that through this simple hydrothermal calcination method, lattice coupling is formed between CeO2 and NiO, which promotes the generation of oxygen vacancies and accelerates the deep phase reconstruction from NiO to NiOOH, showing good OER catalytic activity. However, it can only work stably at a low current density for 72 h, which is not conducive to industrial-scale water electrolysis hydrogen production at high current densities for a long time.

[0006] Obviously, the above literature proves that introducing another phase of material to couple with nickel-based compounds can effectively improve the catalytic activity and stability of nickel-based catalysts, which is a catalyst modification method with application prospects. However, at present, there are few studies on developing an efficient transition metal-based catalyst according to the environment of hydrogen production by electrolyzing water at high current density. Although nickel-based transition metal catalysts have been widely studied in alkaline media, there are still a series of problems, such as low intrinsic activity and easy reconstruction of the catalyst. Research shows that the OER activity of nickel-based transition metal oxides highly depends on the degree and depth of their conversion to corresponding hydroxides, or the active substances generated by complete phase change, so as to improve the OER performance. At present, it is still necessary to further optimize the structure to improve the conductivity and long-term stability of nickel-based catalysts, so as to obtain more excellent electrocatalytic performance to meet the needs of practical applications. Summary of the Invention:

[0007] The purpose of the present invention is to provide an electrocatalytic material that can improve its electrochemical performance in view of the problems of high applied potential and poor kinetic performance of the oxygen evolution reaction occurring at the anode of electrolyzing water. Another purpose of the present invention is to provide a preparation method of the above electrocatalytic material, and still another purpose of the present invention is to provide the application of the above electrocatalytic material. The electrocatalytic material for the oxygen evolution reaction prepared according to this method can enable the electrolyzing water reaction to proceed efficiently under a small applied bias voltage.

[0008] The technical solution of the present invention is: an electrocatalytic material, characterized in that the structure of the electrocatalytic material is a supported structure in which spherical nanoparticles composed of NiO-La2O3 composite nanosheets are loaded on the surface of nickel foam NF, wherein the loading amount of the active component of the electrocatalytic material is 0.012 - 0.018 g / cm 2 , having the characteristics of strong interaction between components and excellent dispersion of the loaded substances; the active components are NiO and La2O3, and the molar ratio of Ni to La is (2 - 10):1. This electrocatalytic material only needs an overpotential of 198 mV to reach a current density of 10 mA cm -2 , and the charge transfer resistance is only 2.38 Ω.

[0009] The present invention also provides a method for preparing the above electrocatalytic material, and the specific steps are as follows:

[0010] (1) Take nickel foam NF and place it in an acid solution for pretreatment, and then ultrasonically wash and dry it for later use;

[0011] (2) Weigh soluble nickel salt, soluble lanthanum salt and urea in proportion, and add deionized water to prepare an electroplating solution;

[0012] (3) Immerse the treated nickel foam NF in step (1) in the prepared electrodeposition solution as the anode, and use a platinum mesh as the cathode. Deposit for a certain time under a constant voltage condition, and then wash and dry the obtained nickel foam in sequence to obtain the NiLa-LDH / NF precursor;

[0013] (4) Calcinate the NiLa-LDH / NF precursor obtained in step (3) to obtain the NiO-La2O3 / NF electrocatalytic material.

[0014] Preferably, the pretreatment acid solution is hydrochloric acid or sulfuric acid solution; the concentration of the acid solution is 0.5 mol / L to 1 mol / L; the ultrasonic temperature is 0 to 5 °C, the ultrasonic power is 300 to 400 W, and the ultrasonic time is 0.5 h to 2 h; the drying temperature is 40 to 50 °C, and the drying time is 6 to 12 h.

[0015] Preferably, the soluble nickel salt is nickel nitrate or nickel chloride; the soluble lanthanum salt is lanthanum nitrate or lanthanum chloride.

[0016] Preferably, the molar ratio of the soluble nickel salt, soluble lanthanum salt to urea is (6 to 30):3:(0.5 to 3); the concentration of the soluble nickel salt in the electrodeposition solution is 0.12 to 0.6 mol / L.

[0017] Preferably, the deposition constant voltage in step (3) is -0.8 V to -1.2 V, the deposition time is 300 s to 1200 s; the drying temperature is 50 to 80 °C, and the drying time is 6 to 12 h.

[0018] Preferably, the calcination temperature in step (4) is 300 to 400 °C, and the calcination time is 1 to 3 h.

[0019] The present invention also provides an application of the above electrocatalytic material in the oxygen evolution reaction during the electrolysis of water to produce hydrogen under alkaline conditions.

[0020] The present invention obtains NiLa-LDH supported on nickel foam through a one-step electrodeposition method, and after vacuum drying, it is calcined in air to obtain NiO-La2O3 / NF. There is a component synergistic catalytic effect between NiO and La2O3. This electrocatalytic material does not require secondary processing and can be directly applied to electrochemical tests. This electrocatalytic material can greatly reduce the overpotential in the electrocatalytic decomposition of water to produce hydrogen. According to the electrochemical performance test, it is proved that NiO-La2O3 has an excellent promoting effect on the electrocatalytic decomposition of water to produce hydrogen, and shows the synergistic catalytic characteristics between the components of the catalytic material.

[0021] Beneficial effects:

[0022] Compared with the existing technology, the present invention has the following advantages and beneficial effects:

[0023] (1) The preparation method of the NiO-La2O3 / NF electrocatalytic material of the present invention solves some problems existing in current nickel-based materials, such as easy aggregation, large catalyst particle size, small specific surface area, covered or insufficiently exposed active sites, etc., and exhibits excellent characteristics of simple preparation method, large specific surface area, uniform particle distribution and good stability, effectively reducing the initial voltage of the oxygen evolution reaction.

[0024] (2) The NiO-La2O3 / NF electrocatalytic material of the present invention grows in-situ on nickel foam and can be directly used for electrochemical testing, avoiding the addition of a binder that affects the conductivity of the catalyst and improving the electrocatalytic performance.

[0025] (3) In the NiO-La2O3 / NF electrocatalytic material of the present invention, the synergistic effect between NiO and La2O3 improves the charge transfer ability of the nickel-based nanocatalyst, solves the disadvantages of poor conductivity and easy aggregation of the nickel-based nanocatalyst, and effectively improves the electrocatalytic ability of the composite nanocatalyst.

[0026] (4) The NiO-La2O3 / NF electrocatalytic material of the present invention only requires an overpotential of 198 mV to reach 10 mA cm -2 of the overpotential, and the charge transfer resistance is only 2.38 Ω, providing a broad prospect for the application of hydrogen production by electrolyzing water. Description of the drawings:

[0027] Figure 1 is the XRD pattern of NiO-La2O3 / NF prepared in Example 1;

[0028] Figure 2 is the XRD pattern of the NiO-La2O3 powder prepared in Example 1;

[0029] Figure 3 is the transmission electron microscope image of the NiO-La2O3 powder prepared in Example 1;

[0030] Figure 4 is the high-resolution transmission electron microscope image of the NiO-La2O3 powder prepared in Example 1;

[0031] Figure 5 is the scanning electron microscope image of NiO-La2O3 / NF prepared in Example 1;

[0032] Figure 6 is the scanning electron microscope image of the NiO-La2O3 powder prepared in Example 1;

[0033] Figure 7OER linear sweep voltammograms of five samples obtained from Example 1, Example 2, Example 3, Example 4, and Comparative Example 1 in 1 mol / L KOH electrolyte;

[0034] Figure 8 Electrochemical impedance spectra of five samples obtained from Example 1, Example 2, Example 3, Example 4, and Comparative Example 1 in 1 mol / L KOH electrolyte;

[0035] Figure 9 Multi-step chronopotentiogram of the NiO-La2O3 / NF electrocatalytic material prepared in Example 1;

[0036] Figure 10 For the NiO-La2O3 / NF electrocatalytic material prepared in Example 1 at a current density of 10 mA cm -2 Chronopotentiogram at. Specific implementation manners:

[0037] The present invention will be further described in detail below in conjunction with specific implementation manners. The examples and comparative examples given are only for clarifying the present invention, rather than limiting the scope of the present invention.

[0038] The experimental methods in the following examples and comparative examples are all conventional methods unless otherwise specified.

[0039] The materials, reagents, etc. used in the following examples and comparative examples can be obtained from commercial sources unless otherwise specified.

[0040] Example 1

[0041] (1) Place nickel foam in 0.5 mol / L sulfuric acid solution and ultrasonicate for 2 h at an ultrasonic temperature of 3 °C and an ultrasonic power of 350 W. After washing, dry it in an oven at 50 °C for 6 h.

[0042] (2) In a standard three-electrode system, dissolve 15 mmol nickel nitrate hexahydrate, 3 mmol lanthanum nitrate hexahydrate, and 1.5 mmol urea in 50 mL of deionized water as the electrolyte. Use the washed nickel foam NF and platinum mesh as the anode and cathode respectively, and perform electro-deposition in the three-electrode system at a constant potential of -1.0 V for 900 s to obtain NiLa-LDH / NF. Dry it in a vacuum oven at 60 °C for 10 h and take it out for standby.

[0043] (3) Place the dried NiLa-LDH in a muffle furnace and calcine it in an air atmosphere at a calcination temperature of 350 °C for 2 h to obtain NiO-La2O3 / NF.

[0044] The results are as follows:

[0045] Figure 1 XRD pattern of NiO-La2O3 / NF prepared in the embodiment of the present invention. It can be seen from the figure that under the current process, obvious diffraction peaks are observed at 44.5°, 51.7° and 76.3°, and these diffraction peaks belong to the diffraction peaks of the substrate nickel foam.

[0046] Figure 2 XRD pattern of NiO-La2O3 powder prepared in this embodiment. It can be seen from the figure that under the current process, obvious diffraction peaks are observed at 36.9°, 43.2°, 62.9°, 75.6° and 79.5°, and these diffraction peaks belong to the diffraction peaks of NiO. Since the La content is small, no diffraction peaks related to La2O3 are observed.

[0047] Figure 3 Transmission electron microscopy image of NiO-La2O3 powder prepared in this embodiment. It can be seen from the figure that the electrocatalytic material NiO-La2O3 presents a nanoflower shape, and is evenly distributed with good morphology, which is consistent with Figure 6 the scanning electron microscopy image.

[0048] Figure 4 High-resolution transmission electron microscopy image of NiO-La2O3 powder prepared in this embodiment. It can be clearly observed from the figure that lattice fringes are observed. The lattice fringe of 0.207 nm corresponds to the (101) crystal plane of NiO, the lattice fringe of 0.254 nm corresponds to the (110) crystal plane of La2O3, and the lattice fringe of 0.286 nm corresponds to the (103) crystal plane of La2O3. And obvious hetero-interfaces are observed, proving that the NiO-La2O3 heterogeneous nanocatalytic material has been successfully prepared.

[0049] Figure 5 Scanning electron microscopy image of NiO-La2O3 / NF prepared in this embodiment. It can be observed from the figure that the electrocatalytic material wraps around the skeleton of the nickel foam and has a large number of microcracks, which indicates that the electrocatalytic material has been successfully loaded on the nickel foam, and the loading amount is 0.0162 g / cm 2 .

[0050] Figure 6 Scanning electron microscopy image of NiO-La2O3 powder prepared in this embodiment. As the magnification increases, the electrocatalytic material presents a nanoflower spherical shape, indicating that the electrocatalytic material has a higher specific surface area, which is helpful for the contact and penetration of the electrolyte.

[0051] Example 2

[0052] (1) Place the nickel foam in a 1 mol / L hydrochloric acid solution and ultrasonicate for 0.5 h at a temperature of 0 °C and a power of 400 W. After washing, dry it in an oven at 45 °C for 8 h.

[0053] (2) In a standard three-electrode system, 30 mmol nickel nitrate hexahydrate, 3 mmol lanthanum nitrate hexahydrate and 0.5 mmol urea were dissolved in 50 mL of deionized water as the electrolyte. The washed nickel foam NF and platinum mesh were used as the cathode and anode, respectively. At a constant potential of -1.2 V, NiLa-LDH / NF was prepared by electrodeposition for 1200 s in the three-electrode system. The mixture was dried in a vacuum oven at 80 °C for 6 h and then taken out for use.

[0054] (3) The dried NiLa-LDH was placed in a muffle furnace and calcined in an air atmosphere at a temperature of 400°C for 1 h to obtain NiO-La2O3 / NF.

[0055] The NiO-La2O3 / NF electrocatalytic material prepared in this example is in the shape of nanoflowers, indicating that the electrocatalytic material has a higher specific surface area, which is conducive to the contact and penetration of the electrolyte. It is evenly distributed and has a good morphology. An obvious heterogeneous interface is observed. At the same time, the electrocatalytic material is wrapped on the skeleton of the nickel foam and has a large number of microcracks, which indicates that the electrocatalytic material has been successfully loaded on the nickel foam, with a loading amount of 0.0173 g / cm 2 .

[0056] Example 3

[0057] (1) The nickel foam was placed in a 1 mol / L sulfuric acid solution and ultrasonicated for 0.5 h at a temperature of 5°C and a power of 300 W. After washing, the nickel foam was dried in an oven at 40°C for 12 h.

[0058] (2) In a standard three-electrode system, 6 mmol nickel nitrate hexahydrate, 3 mmol lanthanum nitrate hexahydrate and 3 mmol urea were dissolved in 50 mL of deionized water as the electrolyte. The washed nickel foam NF and platinum mesh were used as the cathode and anode, respectively, and NiLa-LDH / NF was prepared by electrodeposition in a three-electrode system at a constant potential of -0.8 V for 300 s. The mixture was dried in a vacuum oven at 50°C for 12 h and then taken out for use.

[0059] (3) The dried NiLa-LDH was placed in a muffle furnace and calcined in an air atmosphere at a temperature of 300°C for 3 h to obtain NiO-La2O3 / NF.

[0060] The NiO-La2O3 / NF electrocatalytic material prepared in this example presents a nanoflower shape, indicating that the electrocatalytic material has a higher specific surface area, which helps the contact and penetration of the electrolyte. And it is evenly distributed with good morphology. Also, an obvious heterointerfacial interface is observed. At the same time, the electrocatalytic material wraps around the skeleton of the nickel foam and has a large number of microcracks, which indicates that the electrocatalytic material has been successfully loaded on the nickel foam, and the loading amount is 0.0146 g / cm 2 。

[0061] Example 4

[0062] (1) Place the nickel foam in a 0.5 mol / L hydrochloric acid solution and ultrasonicate for 1 h at a temperature of 5 °C and a power of 350 W. After washing, dry it in an oven at 50 °C for 10 h.

[0063] (2) In a standard three-electrode system, dissolve 15 mmol nickel chloride hexahydrate, 3 mmol lanthanum chloride heptahydrate, and 1.5 mmol urea in 50 mL of deionized water as the electrolyte. Use the washed nickel foam NF and platinum mesh as the cathode and anode respectively, and electro-deposit for 600 s in the three-electrode system at a constant potential of -1.0 V to obtain NiLa-LDH / NF. Dry it in a vacuum oven at 60 °C for 10 h and take it out for standby.

[0064] (3) Place the dried NiLa-LDH in a muffle furnace and calcine it in an air atmosphere at a calcination temperature of 350 °C for 2 h to obtain NiO-La2O3 / NF.

[0065] The NiO-La2O3 / NF electrocatalytic material prepared in this example presents a nanoflower shape, indicating that the electrocatalytic material has a higher specific surface area, which helps the contact and penetration of the electrolyte. And it is evenly distributed with good morphology. Also, an obvious heterointerfacial interface is observed. At the same time, the electrocatalytic material wraps around the skeleton of the nickel foam and has a large number of microcracks, which indicates that the electrocatalytic material has been successfully loaded on the nickel foam, and the loading amount is 0.0147 g / cm 2 。

[0066] Comparative Example 1

[0067] Preparation of RuO2 electrode material:

[0068] Weigh 2.5 mg of RuO2 (commercially available) and add it to a mixed solution composed of 400 μL of deionized water, 80 μL of absolute ethanol, and 20 μL of Nafion solution, ultrasonically dissolve for 60 minutes, and then drop the ultrasonically homogenized RuO2 solution on the nickel foam and dry it at room temperature for standby.

[0069] The above electrocatalytic performance was measured with a mercury / mercuric oxide reference electrode, a graphite counter electrode, and the prepared NiO-La2O3 / NF as the working electrode. The electrolyte was 1 mol / L KOH. In linear sweep voltammetry (LSV), the linear sweep rate was 5 mV / s and the iR compensation was 85%. In the electrochemical impedance spectroscopy measurement, the frequency range tested was 10 -2 to 10 5 Hz, and the amplitude was 5 mV. All potentials were converted to the potential relative to the reversible hydrogen electrode (RHE) using the conversion formula E RHE = E Hg / HgO + 0.0592*pH + 0.098 V.

[0070] The results are as follows:

[0071] Figure 7 OER linear sweep voltammograms of five samples obtained from Example 1, Example 2, Example 3, Example 4, and Comparative Example 1 in 1 mol / L KOH electrolyte. The onset potential of the sample prepared in Example 1 was the lowest. Therefore, the electrocatalytic material at this ratio had the best catalytic activity. As can be seen from the figure, among these electrocatalytic materials, the NiO-La2O3 / NF electrocatalytic material prepared in Example 1 had the lowest onset potential at a current density of 10 mA cm -2 and only required an overpotential of 198 mV, showing the best electrocatalytic activity and excellent application potential at high current densities.

[0072] Figure 8 Electrochemical impedance spectra of five samples obtained from Example 1, Example 2, Example 3, Example 4, and Comparative Example 1 in 1 mol / L KOH electrolyte. Through software fitting analysis, it was found that the charge transfer resistance of NiO-La2O3 / NF obtained in Example 1 was the smallest, only 2.38 Ω, indicating that the charge transfer rate in the electrocatalytic material NiO-La2O3 / NF was the fastest, with excellent reaction kinetics.

[0073] Figure 9 Multi-step chronopotentiograms of the NiO-La2O3 / NF electrocatalytic material prepared in Example 1. As shown in the figure, it continuously worked for 25 hours at current densities of 10 mA cm -2 , 20 mA cm -2 , 50 mA cm -2 , 20 mA cm -2 and 10 mA cm -2 respectively, and the voltage remained stable during the 25 hours without obvious fluctuations. This indicates that the NiO-La2O3 / NF electrocatalytic material has excellent electrocatalytic activity and stability.

[0074] Figure 10 The chronopotentiometry diagram of the NiO-La2O3 / NF electrocatalytic material prepared in Example 1 at a current density of 10 mA cm -2 As can be seen from the figure, at a current density of 10 mA cm -2 it continuously operates for 200 hours, and the voltage remains stable without obvious fluctuations. This indicates that the NiO-La2O3 / NF electrocatalytic material has excellent stability during long-term electrocatalysis.

[0075] The above embodiments are only the preferred technical solutions of the present invention and should not be regarded as limiting the present invention. The embodiments in this application and the features in the embodiments can be arbitrarily combined with each other without conflict. The protection scope of the present invention should be the technical solutions recorded in the claims, including the equivalent replacement methods of the technical features in the technical solutions recorded in the claims. That is, the equivalent replacement improvements within this scope are also within the protection scope of the present invention.

[0076] The above are only the preferred embodiments of the present invention. It should be noted that for those of ordinary skill in the art, without departing from the principle of the present invention, several improvements and refinements can be made, and these improvements and refinements should also be regarded as within the protection scope of the present invention.

Claims

1. An electrocatalytic material, characterized in that, The structure of the electrocatalytic material is a supported structure in which spherical nanoparticles composed of NiO-La2O3 composite nanosheets are loaded on the surface of nickel foam NF. The loading amount of the active component of the electrocatalytic material is 0.012 - 0.018 g / cm 2 ; The active components are NiO and La2O3, and the molar ratio of Ni to La is (2 - 10):

1.

2. A method for preparing the electrocatalytic material as described in claim 1, the specific steps are as follows: (1) Take nickel foam NF and place it in an acid solution for pretreatment. After ultrasonic treatment, washing, and drying, it is reserved for use; (2) Weigh soluble nickel salt, soluble lanthanum salt, and urea in proportion, and add deionized water to prepare an electroplating solution; (3) Immerse the pretreated nickel foam NF in step (1) in the prepared electroplating solution as the anode, and use a platinum mesh as the cathode. Deposit for a certain period of time under a constant voltage condition, and then wash and dry the obtained nickel foam in sequence to obtain the NiLa-LDH / NF precursor; (4) Calcinate the NiLa-LDH / NF precursor obtained in step (3) to obtain the NiO-La2O3 / NF electrocatalytic material.

3. The method according to claim 2, wherein The pretreatment acid solution is hydrochloric acid or sulfuric acid solution; the concentration of the acid solution is 0.5 mol / L to 1 mol / L; the ultrasonic temperature is 0 to 5 °C, the ultrasonic power is 300 to 400 W, and the ultrasonic time is 0.5 h to 2 h; the drying temperature is 40 to 50 °C, and the drying time is 6 to 12 h.

4. The method according to claim 2, wherein The soluble nickel salt is nickel nitrate or nickel chloride; the soluble lanthanum salt is lanthanum nitrate or lanthanum chloride.

5. The method according to claim 2, wherein The molar ratio of the soluble nickel salt, soluble lanthanum salt, and urea is (6 to 30):3:(0.5 to 3); the concentration of the soluble nickel salt in the electroplating solution is 0.12 to 0.6 mol / L.

6. The method according to claim 2, wherein In step (3), the deposition constant voltage is -0.8 V to -1.2 V, the deposition time is 300 s to 1200 s; the drying temperature is 50 to 80 °C, and the drying time is 6 to 12 h.

7. The method according to claim 2, wherein In step (4), the calcination temperature is 300 to 400 °C, and the calcination time is 1 to 3 h.

8. An application of the electrocatalytic material as described in claim 1 in the oxygen evolution reaction during the electrolysis of water to produce hydrogen under alkaline conditions.

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