NF-loaded rare earth element doped Fe-Co-Ni-Cr-Mn (oxygen) hydroxide bifunctional catalyst, and preparation method and application thereof

Abstract

The invention belongs to the technical field of electro-catalysis and energy materials, and particularly relates to a rare earth element doped Fe-Co-Ni-Cr-Mn (oxygen) hydroxide catalyst, a preparation method and application. The preparation method comprises the following steps: preparing a metal salt solution containing iron, cobalt, nickel, chromium and manganese at room temperature by adopting a one-step hydrothermal method, fully and uniformly mixing the metal salt solution, putting the mixture into a high-pressure reaction kettle, adding foamed nickel, dipping, carrying out hydrothermal treatment, washing and drying to obtain the rare earth element doped iron-cobalt-nickel-chromium-manganese (oxygen) hydroxide catalyst loaded on the foamed nickel (NF). The synergistic effect among various metals can accelerate charge transfer, and the introduction of rare earth elements, especially Ce, can regulate and control the electronic structure of the catalyst, so that the active sites are richer, and excellent HER, OER and UOR activities can be obtained.

Description

Technical Field

[0001] This application belongs to the field of electrocatalysis and energy materials technology, specifically relating to rare earth element-doped iron, cobalt, nickel, chromium, and manganese (oxygen) hydroxide bifunctional catalysts, their preparation methods, and applications. Background Technology

[0002] Fossil fuels still account for over 80% of global energy supply, and their large-scale use has caused severe environmental problems. Hydrogen energy, as a zero-carbon, high-energy-density clean energy carrier, has seen water electrolysis as an important development path. However, the water electrolysis process is limited by the high overpotential (1.23V vs. RHE) and slow four-electron transfer kinetics of the oxygen evolution reaction (OER), resulting in low overall energy efficiency. Replacing OER with urea oxidation (UOR, theoretical potential 0.37V vs. RHE) can significantly reduce energy consumption, but the high cost of existing precious metal catalysts (Pt, Ru, etc.) restricts large-scale application.

[0003] High-entropy alloys (HEMs) have emerged as potential alternatives to precious metals due to their synergistic effects of multiple elements and high entropy stability. Their reduced Gibbs free energy can enhance electrocatalytic durability; for example, NiCoFeMnCrP high-entropy phosphides exhibit high stability at 10 mA·cm⁻¹. -2 An overpotential of 270 mV was achieved at the specified current density. However, traditional high-entropy catalysts still face problems such as insufficient active sites and easy detachment from the electrode interface, resulting in catalytic performance and stability not meeting expectations.

[0004] Rare earth elements (such as cerium) are characterized by their multiple valence states (Ce 3+ / Ce 4+ Cerium doping, with its ability to modulate lattice structure, can optimize the electronic structure of catalysts. Studies have shown that cerium doping can induce lattice expansion and electron rearrangement, improving the electron transfer efficiency of transition metal matrices (such as CoO₂). x / CeO x The +2 / +3 valence ratio in the system can be adjusted, but its mechanism of action in high-entropy (oxygen) hydroxide systems remains unclear. In particular, as a rare earth element with high abundance and low cost, the pathway for improving the UOR / OER performance of high-entropy catalysts through lattice distortion and multi-valence synergistic effects still needs further investigation. Summary of the Invention

[0005] Based on the aforementioned technical problems, the purpose of this application is to provide an NF-supported rare earth element-doped iron, cobalt, nickel, chromium, and manganese (oxygen) hydroxide catalyst, its preparation method, and its application, so as to develop a simple and easy-to-operate preparation method, a catalyst with high stability and high catalytic activity, which can be used for both water electrolysis to produce hydrogen and urea electrolysis.

[0006] On the one hand, this application discloses a method for preparing an NF-supported rare earth element-doped iron-cobalt-nickel-chromium-manganese (oxygen) hydroxide bifunctional electrocatalyst, comprising the following steps:

[0007] Metal salt, urea and ammonium fluoride were uniformly mixed in deionized water to obtain the preproduct.

[0008] The preproduct was transferred to a high-pressure reactor, nickel foam was added for impregnation, and the reaction was carried out at 120-180°C for 4-12 hours to obtain product I.

[0009] The product I was centrifuged, washed, and vacuum dried to obtain an NF-supported rare earth element-doped iron-cobalt-nickel-chromium-manganese (oxygen) hydroxide bifunctional electrocatalyst, namely M-FeCoNiCrMnOOH / NF (M=Ce,La,Sm,Yb,Gd,Dy,Nd);

[0010] The metal salts include: rare earth metal sources, trivalent iron sources, divalent cobalt sources, divalent nickel sources, trivalent chromium sources, and divalent manganese sources;

[0011] The molar volume ratio of the rare earth metal source, trivalent iron source, divalent cobalt source, divalent nickel source, trivalent chromium source, divalent manganese source, urea and ammonium fluoride to deionized water is (0-0.3) mmol: (0-1) mmol: (0-1) mmol: (0-1) mmol: (0-1) mmol: (0-1) mmol: (0.2-1.2) mmol: (0.2-0.8) mmol: (10-100) mL; wherein, at least the amount of the rare earth metal source is greater than zero.

[0012] In some optional embodiments, the rare earth metal source includes a trivalent cerium source, a trivalent lanthanum source, a trivalent samarium source, a trivalent ytterbium source, a trivalent gadolinium source, a trivalent dysprosium source, and a pentavalent neodymium source, wherein the molar amounts of the trivalent cerium source, trivalent lanthanum source, trivalent samarium source, trivalent ytterbium source, trivalent gadolinium source, trivalent dysprosium source, and pentavalent neodymium source are (0–0.3) mmol, (0–0.2) mmol, (0–0.2) mmol, (0–0.2) mmol, (0–0.2) mmol, (0–0.2) mmol, and (0–0.2) mmol, respectively.

[0013] In some optional embodiments, the trivalent iron source, divalent cobalt source, divalent nickel source, trivalent chromium source, and divalent manganese source include nitrates, acetates, carbonates, sulfates, and acetone salts of the corresponding metals.

[0014] In some optional embodiments, the vacuum drying conditions are: drying at 60–80°C for 10–12 hours.

[0015] In some optional embodiments, the molar ratio of any one of the trivalent iron source, divalent cobalt source, divalent nickel source, trivalent chromium source, and divalent manganese source to the rare earth metal source is (0-1) mmol:(0-0.1) mmol.

[0016] In some optional embodiments, the molar ratio of ammonium fluoride to urea is 0.324 mmol: 0.833 mmol.

[0017] In some alternative embodiments, the addition of nickel foam is impregnated into the preproduct and uniformly dispersed in the NF three-dimensional porous structure.

[0018] On the other hand, this application provides an NF-supported rare earth element-doped iron-cobalt-nickel-chromium-manganese (oxygen) hydroxide bifunctional catalyst prepared by any of the aforementioned preparation methods.

[0019] In another aspect, this application provides an application of the rare earth element-doped iron-cobalt-nickel-chromium-manganese (oxygen) hydroxide bifunctional catalyst supported on the NF in the electrolysis of water to produce hydrogen.

[0020] In another aspect, this application provides the application of the rare earth element-doped iron-cobalt-nickel-chromium-manganese (oxygen) hydroxide bifunctional catalyst supported by the aforementioned NF in urea electrolysis.

[0021] The preparation method provided in this application successfully yielded an NF-supported rare-earth element-doped iron-cobalt-nickel-chromium-manganese (oxygen) hydroxide composite material, namely a rare-earth element-doped iron-cobalt-nickel-chromium-manganese (oxygen) hydroxide bifunctional catalyst. This material accelerates charge transfer through the synergistic effect between multiple metals, and different electronegativity modulates the electronic structure and charge density of the catalyst. Rare-earth element doping effectively improves the material's conductivity; in particular, the introduction of Ce optimizes the electronic structure of the high-entropy (oxygen) hydroxide surface (e.g., adjusting the d-band center), lowers the water dissociation energy barrier, and stabilizes intermediate product adsorption through oxygen vacancies, thus optimizing the inherent catalytic activity. The nanostructure has a larger specific surface area, exposing more active sites. The synthesized rare-earth element-doped iron-cobalt-nickel-chromium-manganese (oxygen) hydroxide exhibits excellent hydrogen evolution, oxygen evolution, urea reaction activity, and stability. The preparation method of this application is mild and controllable, highly practical, reproducible, environmentally friendly, and uses widely available and low-cost raw materials.

[0022] This application provides a method for preparing and applying a rare earth element-doped iron, cobalt, nickel, chromium, and manganese (oxygen) hydroxide catalyst, which has excellent bifunctional electrocatalytic performance. It can be applied to the field of water electrolysis for hydrogen production and can also be further applied to the field of urea electrooxidation, thus expanding its application scope. Attached Figure Description

[0023] The accompanying drawings are provided to further illustrate the present application and form part of the specification. They are used together with the following detailed description to explain the present application, but do not constitute a limitation thereof. In the drawings:

[0024] Figure 1 The X-ray powder diffraction (XRD) patterns of rare earth element-doped iron-cobalt-nickel-chromium-manganese (oxygen) hydroxide catalysts obtained in Exemplary Embodiments 1 to 10 of this application are shown.

[0025] Figure 2 This is a morphology analysis image (SEM) of the rare earth element Ce-doped FeCoNiCrMnOOH / NF material obtained in Exemplary Example 1 of this application;

[0026] Figure 3 Linear sweep voltammetry (LSV) curves comparing the hydrogen evolution reaction performance of rare earth element-doped iron-cobalt-nickel-chromium-manganese (oxygen) hydroxide catalyst materials obtained in Exemplary Embodiments 1 to 10 of this application;

[0027] Figure 4 Linear sweep voltammetry (LSV) curves comparing the oxygen evolution reaction performance of rare earth element-doped iron-cobalt-nickel-chromium-manganese (oxygen) hydroxide catalyst materials obtained in Exemplary Embodiments 1 to 10 of this application in 1M KOH;

[0028] Figure 5 Linear sweep voltammetry (LSV) curves of the urea electro-oxidation reaction in 1M KOH + 0.33M Urea were obtained for exemplary embodiments 1 to 10 of this application. Detailed Implementation

[0029] The following specific examples further illustrate this application. It should be understood that these embodiments are for illustrative purposes only and are not intended to limit the scope of this application. Furthermore, it should be understood that after reading the teachings of this application, those skilled in the art can make various alterations or modifications to this application, and these equivalent forms also fall within the scope defined by the appended claims.

[0030] The method for preparing an NF-supported rare earth element-doped iron-cobalt-nickel-chromium-manganese (oxygen) hydroxide bifunctional electrocatalyst according to specific embodiments of this application includes the following steps:

[0031] Metal salts, including rare earth metal sources, trivalent iron sources, divalent cobalt sources, divalent nickel sources, trivalent chromium sources and divalent manganese sources, urea and ammonium fluoride are uniformly mixed in deionized water to obtain a preproduct.

[0032] The preproduct is then transferred to a high-pressure reactor, nickel foam is added for impregnation, and the mixture is reacted at 120–180°C for 4–12 hours to obtain product I.

[0033] Product I was centrifuged, washed, and vacuum dried to obtain the NF-supported rare earth element-doped iron-cobalt-nickel-chromium-manganese (oxygen) hydroxide bifunctional electrocatalyst, namely M-FeCoNiCrMnOOH / NF (M=Ce,La,Sm,Yb,Gd,Dy,Nd);

[0034] The molar volume ratio of rare earth metal source, trivalent iron source, divalent cobalt source, divalent nickel source, trivalent chromium source, divalent manganese source, urea and ammonium fluoride to deionized water is (0-0.3) mmol: (0-1) mmol: (0-1) mmol: (0-1) mmol: (0-1) mmol: (0-1) mmol: (0.2-1.2) mmol: (0.2-0.8) mmol: (10-100) mL; wherein, at least the amount of the rare earth metal source is greater than zero. For example, the molar volume ratio of rare earth metal source, trivalent iron source, divalent cobalt source, divalent nickel source, trivalent chromium source, divalent manganese source, urea and ammonium fluoride to deionized water can be: 0.1mmol:0.3mmol:0.3mmol:0.3mmol:0.3mmol:0.3mmol:0.6mmol:0.5mmol:80ml; 0.05mmol:0.6mmol:0.6mmol:0.6mmol:0.6mmol:1.2mmol:0.8mmol:100ml, etc., and so on. These cannot all be listed here. Some specific examples are provided below for illustrative purposes.

[0035] It should be noted that as long as it is within the scope of this application, the purpose and expected technical effect of this application can be achieved.

[0036] In a specific embodiment of this application, the pretreatment process for nickel foam can be performed according to the following conventional steps:

[0037] 1) Use dilute hydrochloric acid with a concentration of 2-4M as the washing solution and ultrasonically clean the foamed nickel for 10-20 minutes;

[0038] 2) Use ethanol as the washing solution and ultrasonically clean the nickel foam for 10-20 minutes;

[0039] 3) Use deionized water as the washing solution and ultrasonically clean the foamed nickel for 10-20 minutes;

[0040] 4) Vacuum dry at 50-60℃ for 8-10 hours.

[0041] Example 1

[0042] A method for synthesizing Ce (30 mg) doped FeCoNiCrMnOOH / NF bifunctional catalyst includes the following steps:

[0043] Weigh 0.03g Ce(NO3)3·6H2O, 0.202g Fe(NO3)3·9H2O, 0.146g Co(NO3)2·6H2O, 0.145g Ni(NO3)2·6H2O, 0.2g Cr(NO3)3·9H2O, 0.125g Mn(NO3)2·4H2O, 0.012g ammonium fluoride, and 0.05g urea into a 100mL beaker, add 36mL of deionized water, and stir evenly on a magnetic stirrer at an appropriate speed. Then, transfer the mixture to a 50mL high-pressure reactor, add pretreated nickel foam (NF), and hydrothermally react in an oven at 140℃ for 8 hours. The sample was washed three times with ethanol and deionized water. The sample was then picked up with tweezers and placed evenly in a petri dish. The dish was then placed in a vacuum drying oven and dried at 60°C for 10 hours to obtain 30Ce-FeCoNiCrMnOOH / NF material.

[0044] Example 2

[0045] A method for synthesizing Ce (15 mg) doped FeCoNiCrMnOOH / NF bifunctional catalyst includes the following steps:

[0046] Weigh 0.015g Ce(NO3)3·6H2O, 0.202g Fe(NO3)3·9H2O, 0.146g Co(NO3)2·6H2O, 0.145g Ni(NO3)2·6H2O, 0.2g Cr(NO3)3·9H2O, 0.125g Mn(NO3)2·4H2O, 0.012g ammonium fluoride, and 0.05g urea into a 100mL beaker, add 36mL of deionized water, and stir evenly on a magnetic stirrer at an appropriate speed. Then, transfer the mixture to a 50mL high-pressure reactor, add pretreated nickel foam (NF), and hydrothermally react in an oven at 140℃ for 8 hours. The sample was washed three times with ethanol and deionized water. The sample was then picked up with tweezers and placed evenly in a petri dish. The dish was then placed in a vacuum drying oven and dried at 60°C for 10 hours to obtain 15Ce-FeCoNiCrMnOOH / NF material.

[0047] Example 3

[0048] A method for synthesizing Ce (45 mg) doped FeCoNiCrMnOOH / NF bifunctional catalyst includes the following steps:

[0049] Weigh 0.045g Ce(NO3)3·6H2O, 0.202g Fe(NO3)3·9H2O, 0.146g Co(NO3)2·6H2O, 0.145g Ni(NO3)2·6H2O, 0.2g Cr(NO3)3·9H2O, 0.125g Mn(NO3)2·4H2O, 0.012g ammonium fluoride, and 0.05g urea into a 100mL beaker, add 36mL of deionized water, and stir evenly on a magnetic stirrer at an appropriate speed. Then, transfer the mixture to a 50mL high-pressure reactor, add pretreated nickel foam (NF), and hydrothermally react in an oven at 140℃ for 8 hours. The sample was washed three times with ethanol and deionized water. The sample was then picked up with tweezers and placed evenly in a petri dish. The dish was then placed in a vacuum drying oven and dried at 60°C for 10 hours to obtain 45Ce-FeCoNiCrMnOOH / NF material.

[0050] Example 4

[0051] A method for synthesizing a La (30 mg) doped FeCoNiCrMnOOH / NF bifunctional catalyst includes the following steps:

[0052] Weigh 0.03g La(NO3)3·6H2O, 0.202g Fe(NO3)3·9H2O, 0.146g Co(NO3)2·6H2O, 0.145g Ni(NO3)2·6H2O, 0.2g Cr(NO3)3·9H2O, 0.125g Mn(NO3)2·4H2O, 0.012g ammonium fluoride, and 0.05g urea into a 100mL beaker, add 36mL of deionized water, and stir evenly on a magnetic stirrer at an appropriate speed. Then, transfer the mixture to a 50mL high-pressure reactor, add pretreated nickel foam (NF), and hydrothermally react in an oven at 140℃ for 8 hours. The sample was washed three times with ethanol and deionized water. The sample was then picked up with tweezers and placed evenly in a petri dish. The dish was then placed in a vacuum drying oven and dried at 60°C for 10 hours to obtain 30La-FeCoNiCrMnOOH / NF material.

[0053] Example 5

[0054] A method for synthesizing Sm (30 mg) doped FeCoNiCrMnOOH / NF bifunctional catalyst includes the following steps:

[0055] Weigh 0.03g Sm(NO3)3·6H2O, 0.202g Fe(NO3)3·9H2O, 0.146g Co(NO3)2·6H2O, 0.145g Ni(NO3)2·6H2O, 0.2g Cr(NO3)3·9H2O, 0.125g Mn(NO3)2·4H2O, 0.012g ammonium fluoride, and 0.05g urea into a 100mL beaker, add 36mL of deionized water, and stir evenly on a magnetic stirrer at an appropriate speed. Then, transfer the mixture to a 50mL high-pressure reactor, add pretreated nickel foam (NF), and hydrothermally react in an oven at 140℃ for 8 hours. The sample was washed three times with ethanol and deionized water. The sample was then picked up with tweezers and placed evenly in a petri dish. The dish was then placed in a vacuum drying oven and dried at 60°C for 10 hours to obtain 30Sm-FeCoNiCrMnOOH / NF material.

[0056] Example 6

[0057] A method for synthesizing Yb (30 mg) doped FeCoNiCrMnOOH / NF bifunctional catalyst includes the following steps:

[0058] Weigh 0.03g Yb(NO3)3·5H2O, 0.202g Fe(NO3)3·9H2O, 0.146g Co(NO3)2·6H2O, 0.145g Ni(NO3)2·6H2O, 0.2g Cr(NO3)3·9H2O, 0.125g Mn(NO3)2·4H2O, 0.012g ammonium fluoride, and 0.05g urea into a 100mL beaker, add 36mL deionized water, and stir evenly on a magnetic stirrer at an appropriate speed. Then, transfer the mixture to a 50mL high-pressure reactor, add pretreated nickel foam (NF), and hydrothermally react in an oven at 140℃ for 8 hours. The sample was washed three times with ethanol and deionized water. The sample was then picked up with tweezers and placed evenly in a petri dish. The dish was then placed in a vacuum drying oven and dried at 60°C for 10 hours to obtain 30Yb-FeCoNiCrMnOOH / NF material.

[0059] Example 7

[0060] A method for synthesizing a Gd (30 mg) doped FeCoNiCrMnOOH / NF bifunctional catalyst includes the following steps:

[0061] Weigh 0.03g Gd(NO3)3·6H2O, 0.202g Fe(NO3)3·9H2O, 0.146g Co(NO3)2·6H2O, 0.145g Ni(NO3)2·6H2O, 0.2g Cr(NO3)3·9H2O, 0.125g Mn(NO3)2·4H2O, 0.012g ammonium fluoride, and 0.05g urea into a 100mL beaker, add 36mL of deionized water, and stir evenly on a magnetic stirrer at an appropriate speed. Then, transfer the mixture to a 50mL high-pressure reactor, add pretreated nickel foam (NF), and hydrothermally react in an oven at 140℃ for 8 hours. The sample was washed three times with ethanol and deionized water. The sample was then picked up with tweezers and placed evenly in a petri dish. The dish was then placed in a vacuum drying oven and dried at 60°C for 10 hours to obtain 30Gd-FeCoNiCrMnOOH / NF material.

[0062] Example 8

[0063] A method for synthesizing Dy (30 mg) doped FeCoNiCrMnOOH / NF bifunctional catalyst includes the following steps:

[0064] Weigh 0.03g Dy(NO3)3·6H2O, 0.202g Fe(NO3)3·9H2O, 0.146g Co(NO3)2·6H2O, 0.145g Ni(NO3)2·6H2O, 0.2g Cr(NO3)3·9H2O, 0.125g Mn(NO3)2·4H2O, 0.012g ammonium fluoride, and 0.05g urea into a 100mL beaker, add 36mL of deionized water, and stir evenly on a magnetic stirrer at an appropriate speed. Then, transfer the mixture to a 50mL high-pressure reactor, add pretreated nickel foam (NF), and hydrothermally react in an oven at 140℃ for 8 hours. The sample was washed three times with ethanol and deionized water. The sample was then picked up with tweezers and placed evenly in a petri dish. The dish was then placed in a vacuum drying oven and dried at 60°C for 10 hours to obtain 30Dy-FeCoNiCrMnOOH / NF material.

[0065] Example 9

[0066] A method for synthesizing Nd(30mg) doped FeCoNiCrMnOOH / NF bifunctional catalyst includes the following steps:

[0067] Weigh 0.03g Nd(NO3)3·6H2O, 0.202g Fe(NO3)3·9H2O, 0.146g Co(NO3)2·6H2O, 0.145g Ni(NO3)2·6H2O, 0.2g Cr(NO3)3·9H2O, 0.125g Mn(NO3)2·4H2O, 0.012g ammonium fluoride, and 0.05g urea into a 100mL beaker, add 36mL deionized water, and stir evenly on a magnetic stirrer at an appropriate speed. Then, transfer the mixture to a 50mL high-pressure reactor, add pretreated nickel foam (NF), and hydrothermally react in an oven at 140℃ for 8 hours. The sample was washed three times with ethanol and deionized water. The sample was then picked up with tweezers and placed evenly in a petri dish. The dish was then placed in a vacuum drying oven and dried at 60°C for 10 hours to obtain 30Nd-FeCoNiCrMnOOH / NF material.

[0068] Example 10

[0069] The synthesis method of FeCoNiCrMnOOH / NF bifunctional catalyst includes the following steps:

[0070] Weigh 0.202g Fe(NO3)3·9H2O, 0.146g Co(NO3)2·6H2O, 0.145g Ni(NO3)2·6H2O, 0.2g Cr(NO3)3·9H2O, 0.125g Mn(NO3)2·4H2O, 0.012g ammonium fluoride, and 0.05g urea into a 100mL beaker, add 36mL of deionized water, and stir evenly on a magnetic stirrer at an appropriate speed. Then, transfer the mixture to a 50mL high-pressure reactor, add pretreated nickel foam (NF), and hydrothermally react at 140℃ for 8h in an oven. Wash the sample three times with ethanol and deionized water, use tweezers to pick up the sample and place it evenly in a petri dish, then place it in a vacuum drying oven and dry at 60℃ for 10h to obtain FeCoNiCrMnOOH / NF material.

[0071] The raw materials and quantities used in the above embodiments are summarized in the table below:

[0072]

[0073]

[0074] Step one in the above implementation case is only an exemplary operation. Large industrial stirred reactors can be used to improve production efficiency and product quantity.

[0075] like Figure 1As shown, the XRD pattern of the rare earth metal-doped iron-cobalt-nickel-chromium-manganese (oxy) hydroxide catalyst was obtained by referring to the method of the embodiment. As can be seen from the figure, the presence of (oxy) hydroxide is confirmed by the diffraction peaks at 39.2°, 52.0° and 55.9°, which correspond to the (301), (600) and (521) crystal planes of β-FeOOH (JCPDS: 34-1266), respectively.

[0076] like Figure 2 The image shows a SEM image of a rare-earth metal-doped iron-cobalt-nickel-chromium-manganese (oxygen) hydroxide catalyst. The image reveals that the ordered nanosheets form a three-dimensional stacked structure, exposing active sites for adsorption / desorption reaction intermediates.

[0077] like Figure 3 , 4 As shown in Figure 5, the materials obtained above were used as electrode materials for oxygen evolution, hydrogen evolution, and urea electro-oxidation in water electrolysis for hydrogen production. Polarization curves of the oxygen evolution, hydrogen evolution, and urea electro-oxidation reactions were tested using a three-electrode system, and linear sweep voltammetry (LSV) curves of the reactions were also presented. The figures show that 30Ce-FeCoNiCrMnOOH / NF exhibits the best HER, OER, and UOR performance, indicating that a doping concentration of 30 mg Ce accelerates the reaction kinetics, exposes more active sites, improves hydrogen production efficiency, and has better application prospects.

[0078] The above description is merely an embodiment of this application and does not limit the patent scope of this application. Any equivalent structural or procedural transformations made using the description of this application, or direct or indirect applications in other related technical fields, are similarly included within the patent protection scope of this application.

Claims

1. A method for preparing an NF-supported rare earth element-doped iron-cobalt-nickel-chromium-manganese (oxygen) hydroxide bifunctional electrocatalyst, characterized in that, Includes the following steps: Metal salt, urea and ammonium fluoride were uniformly mixed in deionized water to obtain the preproduct. The preproduct was transferred to a high-pressure reactor, nickel foam was added for impregnation, and the reaction was carried out at 120-180°C for 4-12 hours to obtain product I. The product I was centrifuged, washed, and vacuum dried to obtain an NF-supported rare earth element-doped iron-cobalt-nickel-chromium-manganese (oxygen) hydroxide bifunctional electrocatalyst, namely M-FeCoNiCrMnOOH / NF (M=Ce,La,Sm,Yb,Gd,Dy,Nd); The metal salts include: rare earth metal sources, trivalent iron sources, divalent cobalt sources, divalent nickel sources, trivalent chromium sources, and divalent manganese sources; The molar volume ratio of the rare earth metal source, trivalent iron source, divalent cobalt source, divalent nickel source, trivalent chromium source, divalent manganese source, urea and ammonium fluoride to deionized water is (0-0.3) mmol: (0-1) mmol: (0-1) mmol: (0-1) mmol: (0-1) mmol: (0-1) mmol: (0.2-1.2) mmol: (0.2-0.8) mmol: (10-100) mL; Wherein, at least the amount of the rare earth metal source used is greater than zero.

2. The preparation method according to claim 1, characterized in that, The rare earth metal sources include trivalent cerium sources, trivalent lanthanum sources, trivalent samarium sources, trivalent ytterbium sources, trivalent gadolinium sources, trivalent dysprosium sources, and pentavalent neodymium sources, with the molar amounts of the trivalent cerium sources, trivalent lanthanum sources, trivalent samarium sources, trivalent ytterbium sources, trivalent gadolinium sources, trivalent dysprosium sources, and pentavalent neodymium sources being (0–0.3) mmol, (0–0.2) mmol, (0–0.2) mmol, (0–0.2) mmol, (0–0.2) mmol, (0–0.2) mmol, and (0–0.2) mmol, respectively.

3. The preparation method according to claim 1, characterized in that, The trivalent iron source, divalent cobalt source, divalent nickel source, trivalent chromium source, and divalent manganese source include nitrates, acetates, carbonates, sulfates, and acetone salts of the corresponding metals.

4. The preparation method according to claim 1, characterized in that, The vacuum drying conditions are: drying at 60-80℃ for 10-12 hours.

5. The preparation method according to claim 1, characterized in that, The molar ratio of any one of the trivalent iron source, divalent cobalt source, divalent nickel source, trivalent chromium source, and divalent manganese source to the rare earth metal source is (0-1) mmol: (0-0.1) mmol.

6. The preparation method according to claim 1, characterized in that, The molar ratio of ammonium fluoride to urea is 0.324 mmol: 0.833 mmol.

7. The preparation method according to claim 1, characterized in that, The addition of nickel foam impregnation is used to uniformly disperse the preproduct into the NF three-dimensional porous structure.

8. An NF-supported rare earth element-doped iron-cobalt-nickel-chromium-manganese (oxygen) hydroxide bifunctional catalyst prepared by the preparation method according to any one of claims 1 to 7.

9. The application of the NF-supported rare earth element-doped iron-cobalt-nickel-chromium-manganese (oxygen) hydroxide bifunctional catalyst as described in claim 8 in the electrolysis of water to produce hydrogen.

10. The application of the NF-supported rare earth element-doped iron-cobalt-nickel-chromium-manganese (oxygen) hydroxide bifunctional catalyst as described in claim 8 in urea electrolysis.

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