Iron-nickel-molybdenum hydroxyl oxide, and preparation method and application thereof

Abstract

The application discloses an iron-nickel-molybdenum hydroxyl oxide and a preparation method and application thereof. The preparation method of the iron-nickel-molybdenum hydroxyl oxide comprises the following steps: mixing ammonium molybdate, nickel chloride and water to react, and preparing a suspension containing nickel molybdate; mixing an aqueous solution of ferric chloride with the suspension containing the nickel molybdate, and preparing a suspension containing iron ion modified nickel molybdate; mixing the suspension containing the iron ion modified nickel molybdate with an aqueous solution of urea, and performing a hydrothermal reaction, so as to obtain an intermediate product through solid-liquid separation; mixing the intermediate product with an alkali solution, and performing etching, so as to prepare the iron-nickel-molybdenum hydroxyl oxide. The preparation method of the iron-nickel-molybdenum hydroxyl oxide can solve the problems of disorder stacking and element segregation which are easily caused by the traditional hydrothermal method for preparing the iron-nickel-molybdenum hydroxyl oxide, and the problems of low activity and low stability are solved by adjusting the mixing sequence of raw materials. The preparation method has high yield, can be used for large-scale preparation of the iron-nickel-molybdenum hydroxyl oxide, and is easy to be industrialized.

Description

Technical Field

[0001] This application belongs to the field of anion exchange membrane electrolysis catalysts, and relates to an iron-nickel-molybdenum hydroxy oxide, its preparation method and application. Background Technology

[0002] Anion exchange membrane water electrolysis (AEMWE) is a solid electrolyte water electrolysis technology in an alkaline environment. It is an emerging green hydrogen production technology that combines the advantages of alkaline water electrolysis and proton exchange membrane electrolysis. The core technology uses anion exchange membranes as electrolytes and separators to decompose water into hydrogen and oxygen under the action of direct current.

[0003] Iron-nickel-molybdenum hydroxyl oxides (FeNiMo) are a class of high-performance non-precious metal catalysts for hydrogen production via water electrolysis. However, current methods for preparing FeNiMo hydroxyl oxides, such as magnetron sputtering, electrochemical deposition, and spin coating, are costly, cannot be used for large-scale production, and are not stable enough for electrocatalytic applications. Furthermore, FeNiMo hydroxyl oxides prepared by hydrothermal methods exhibit low activity and low stability. Summary of the Invention

[0004] Therefore, it is necessary to provide an iron-nickel-molybdenum hydroxy oxide, its preparation method and application, and the provided preparation method can prepare iron-nickel-molybdenum hydroxy oxide with high catalytic activity on a large scale.

[0005] In some embodiments, a method for preparing iron-nickel-molybdenum hydroxyl oxide is provided, comprising the following steps:

[0006] Ammonium molybdate, nickel chloride, and water are mixed and reacted to prepare a suspension containing nickel molybdate.

[0007] A suspension of nickel molybdate containing iron ions was prepared by mixing an aqueous solution of ferric chloride with the suspension containing nickel molybdate.

[0008] The suspension of the iron-modified nickel molybdate was mixed with an aqueous urea solution and subjected to a hydrothermal reaction. The intermediate product was obtained by solid-liquid separation.

[0009] The intermediate product is mixed with an alkaline solution and etched to prepare the iron-nickel-molybdenum hydroxy oxide;

[0010] The iron-nickel-molybdenum hydroxy oxide does not contain a base material.

[0011] In some embodiments, in the provided method for preparing iron-nickel-molybdenum hydroxyl oxide, the mass ratio of ammonium molybdate, nickel chloride, ferric chloride and urea is (0.9~1.7):(0.6~1.2):(0.05~0.1):(0.1~0.3).

[0012] In some embodiments, in the provided method for preparing iron-nickel-molybdenum hydroxyl oxide, the mass ratio of ammonium molybdate, nickel chloride, ferric chloride and urea is (1~1.3):(0.8~1.1):(0.06~0.08):(0.2~0.26).

[0013] In some embodiments, the provided method for preparing iron-nickel-molybdenum hydroxyl oxide satisfies one or more of the following conditions:

[0014] (1) In the reaction step of mixing ammonium molybdate, nickel chloride and water, the reaction time is 1h~5h;

[0015] (2) Mix the ferric chloride aqueous solution with the nickel molybdate suspension and stir for 0.5 h to 1 h;

[0016] (3) The suspension of iron-modified nickel molybdate is mixed with urea aqueous solution and stirred for 0.5h to 1h.

[0017] In some embodiments, in the provided method for preparing iron-nickel-molybdenum hydroxyl oxide, the mass ratio of ammonium molybdate to water is (0.9~1.7):60.

[0018] In some embodiments, the provided method for preparing iron-nickel-molybdenum hydroxyl oxide satisfies one or more of the following conditions:

[0019] (1) The concentration of ferric chloride in the ferric chloride aqueous solution is 1 mol / L to 2 mol / L;

[0020] (2) The concentration of urea in the urea aqueous solution is 2 mol / L to 3 mol / L;

[0021] (3) The temperature of the hydrothermal reaction is 120℃~130℃ and the time of the hydrothermal reaction is 5h~15h.

[0022] In some embodiments, the provided method for preparing iron-nickel-molybdenum hydroxyl oxide satisfies one or more of the following conditions:

[0023] (1) The mass-to-volume ratio of the intermediate product to the alkaline solution is 100 mg: (100~200) mL;

[0024] (2) The concentration of the alkaline solution is 1 mol / L to 2 mol / L;

[0025] (3) The alkaline solution is one or both of sodium hydroxide aqueous solution and potassium hydroxide aqueous solution;

[0026] (4) The etching time is 20h~60h.

[0027] In some embodiments, the iron-nickel-molybdenum hydroxyl oxide prepared by the preparation method described above is provided.

[0028] In some embodiments, the iron-nickel-molybdenum hydroxyoxide is needle-shaped.

[0029] In some embodiments, the needle-like structure has a length of 3μm to 6μm and a diameter of 75nm to 120nm.

[0030] In some embodiments, the application of the aforementioned iron-nickel-molybdenum hydroxyoxide is provided, wherein the iron-nickel-molybdenum hydroxyoxide is used as a catalyst in an anion exchange membrane water electrolysis hydrogen production system.

[0031] In some embodiments, the electrolyte used in the anion exchange membrane water electrolysis hydrogen production system is an alkaline solution.

[0032] The aforementioned method for preparing iron-nickel-molybdenum hydroxyl oxides eliminates the need for a substrate material. By controlling the mixing sequence of the raw materials, it enables large-scale preparation of iron-nickel-molybdenum hydroxyl oxides, and the resulting oxides exhibit high catalytic activity. The provided method is low-cost, high-yield, and easily industrialized. Attached Figure Description

[0033] To more clearly illustrate the technical solutions in the embodiments and examples of this application, and to more completely understand this application and its beneficial effects, the accompanying drawings used in the description of the embodiments or examples will be briefly introduced below. Obviously, the drawings described below are merely some embodiments of this application. Those skilled in the art can obtain other drawings based on these drawings without any creative effort.

[0034] Figure 1 Scanning electron microscope image of the iron-nickel-molybdenum hydroxyl oxide prepared in Example 2;

[0035] Figure 2 This is a scanning electron microscope image of the iron-nickel-molybdenum hydroxyl oxide prepared in Example 4;

[0036] Figure 3 The energy dispersive X-ray spectroscopy spectrum of the iron-nickel-molybdenum hydroxyl oxide prepared in Example 2 is shown below.

[0037] Figure 4 X-ray diffraction (XRD) results of the iron-nickel-molybdenum hydroxyl oxides prepared in Example 2 and Comparative Example 1;

[0038] Figure 5 Linear sweep voltammetric polarization curves of iron-nickel-molybdenum hydroxyoxides for Example 2 and Comparative Example 1. Detailed Implementation

[0039] To facilitate understanding of the present invention, a more complete description will be given below with reference to the accompanying drawings. Preferred embodiments of the invention are shown in the drawings. However, the invention can be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided to provide a thorough and complete understanding of the disclosure of the invention.

[0040] It should be noted that when a component is said to be "fixed to" another component, it can be directly attached to the other component or there may be an intervening component. When a component is said to be "connected to" another component, it can be directly connected to the other component or there may be an intervening component.

[0041] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used herein in the description of the invention is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0042] Unless otherwise stated or in case of contradiction, the terms or phrases used herein shall have the following meanings:

[0043] The terms "and / or," "or / and," and "and / or" as used in this application encompass any one of two or more related listed items, as well as any and all combinations of the related listed items. These arbitrary and all combinations include any two related listed items, any more related listed items, or a combination of all related listed items. It should be noted that when at least three items are connected using at least two conjunctions selected from "and / or," "or / and," and "and / or," it should be understood that in this application, the technical solution undoubtedly includes solutions connected by "logical AND," and also undoubtedly includes solutions connected by "logical OR." For example, "A and / or B" includes three parallel solutions: A, B, and "a combination of A and B."

[0044] In this application, the terms "multiple", "various", "multiple times", "multi-dimensional", etc., unless otherwise specified, refer to a quantity greater than or equal to 2. For example, "one or more" means one or more than or equal to two.

[0045] The terms “combinations thereof,” “any combination thereof,” and “any combination thereof” as used in this application include all suitable combinations of any two or more of the listed items.

[0046] In this application, the term "suitable" as used in "suitable combination", "suitable method", "any suitable method", etc., refers to the ability to implement the technical solution of this application, solve the technical problem of this application, and achieve the expected technical effect of this application.

[0047] In this application, terms such as "preferred," "better," "more suitable," and "ideal" are merely used to describe implementation methods or embodiments that achieve better results, and should be understood not to limit the scope of protection of this application.

[0048] In this application, terms such as "further," "even further," and "particularly" are used to describe purposes and indicate differences in content, but should not be construed as limiting the scope of protection of this application.

[0049] In this application, "optionally," "optionally," and "optional" mean that something is optional, that is, it means that it is selected from either "with" or "without." If there are multiple "optional" entries in a technical solution, unless otherwise specified, and there are no contradictions or mutual constraints, each "optional" entry shall be independent.

[0050] In this invention, the terms "first aspect," "second aspect," "third aspect," and "fourth aspect," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance or quantity, nor should they be construed as implicitly indicating the importance or quantity of the indicated technical features. Moreover, "first," "second," "third," and "fourth," etc., serve only as a non-exhaustive enumeration and should be understood not to constitute a closed limitation on quantity.

[0051] In this application, the technical features described in an open-ended manner include both closed technical solutions consisting of the listed features and open technical solutions that include the listed features.

[0052] In this application, numerical intervals (i.e., numerical ranges) are involved. Unless otherwise specified, the selected numerical distributions within the aforementioned numerical intervals are considered continuous and include the two endpoints (i.e., the minimum and maximum values) of the numerical range, as well as every value between these two endpoints. Unless otherwise specified, when a numerical interval refers only to integers within that interval, it includes the two endpoint integers of the numerical range, as well as every integer between the two endpoints. In this document, this is equivalent to directly listing every integer. For example, if t is an integer selected from 1 to 10, it means that t is any integer selected from the group of integers consisting of 1, 2, 3, 4, 5, 6, 7, 8, 9, and 10. Furthermore, when multiple ranges are provided to describe features or characteristics, these ranges can be merged. In other words, unless otherwise specified, the ranges disclosed herein should be understood to include any and all subranges to which they are included.

[0053] Unless otherwise specified, the temperature parameters in this application are permitted to be either constant-temperature treatment or variations within a certain temperature range. It should be understood that the constant-temperature treatment allows temperature fluctuations within the precision range of the instrument control, such as ±5℃, ±4℃, ±3℃, ±2℃, or ±1℃.

[0054] In this application, % (w / w) and wt% both represent weight percentage, % (v / v) refers to volume percentage, and % (w / v) refers to mass-volume percentage.

[0055] In this application, "room temperature" generally refers to 5℃~30℃, and more preferably 25±5℃.

[0056] In some embodiments, a method for preparing iron-nickel-molybdenum hydroxyl oxide is provided, comprising the following steps:

[0057] Ammonium molybdate, nickel chloride, and water are mixed and reacted to prepare a suspension containing nickel molybdate.

[0058] A suspension of nickel molybdate modified with iron ions was prepared by mixing an aqueous solution of ferric chloride with a suspension containing nickel molybdate.

[0059] A suspension of iron-modified nickel molybdate was mixed with an aqueous urea solution and subjected to a hydrothermal reaction. The intermediate product was obtained by solid-liquid separation.

[0060] The intermediate product was mixed with an alkaline solution and etched to prepare iron-nickel-molybdenum hydroxy oxide;

[0061] Among them, the iron-nickel-molybdenum hydroxyl oxide does not contain a base material.

[0062] Traditional hydrothermal methods for preparing iron-nickel-molybdenum hydroxyl oxides are prone to disordered stacking and elemental segregation, leading to low activity and stability. In the proposed method, ammonium molybdate and nickel chloride react in water to form nickel molybdate, creating a suspension with nickel molybdate precipitate as the dispersed phase and an aqueous solution as the dispersion medium. This suspension is then mixed with an aqueous solution of ferric chloride, where iron ions modify the nickel molybdate. The addition of urea provides a uniform and controllable alkaline environment, allowing the molybdate ions to fully react and promoting the formation of needle-like morphologies. The hydrothermal reaction synthesizes the Fe-NiMoO4 intermediate, and the Mo in the intermediate is etched out with an alkaline solution to generate iron-nickel-molybdenum hydroxyl oxides.

[0063] The provided preparation method requires no substrate material and produces iron-nickel-molybdenum hydroxyl oxides in powder form. The raw materials used, such as nickel chloride and ferric chloride, are readily available and inexpensive. No explosive nitrate compounds are generated during the synthesis process, ensuring high safety. The high yield allows for large-scale industrial production and can be used for industrial catalytic hydrogen production. The provided method enables scale-up preparation of iron-nickel-molybdenum hydroxyl oxides in a hydrothermal reactor, with production efficiency unaffected by the reactor size. In contrast, current methods requiring substrate materials are prone to uneven growth and detachment during large-scale production, hindering the efficient and stable synthesis of industrially required catalysts.

[0064] In some embodiments, in the provided method for preparing iron-nickel-molybdenum hydroxyl oxide, the mass ratio of ammonium molybdate, nickel chloride, ferric chloride and urea is (0.9~1.7):(0.6~1.2):(0.05~0.1):(0.1~0.3).

[0065] In some embodiments, in the provided method for preparing iron-nickel-molybdenum hydroxyl oxide, the mass ratio of ammonium molybdate, nickel chloride, ferric chloride and urea is (1~1.3):(0.8~1.1):(0.06~0.08):(0.2~0.26).

[0066] Understandably, in the mass ratio of ammonium molybdate, nickel chloride, ferric chloride, and urea, ammonium molybdate can be 0.9 to 1.7, or 1 to 1.3, for example, 0.9, 1, 1.1, 1.2, 1.3, 1.4, 1.5, 1.6, 1.7, etc., or any range of two of the aforementioned values.

[0067] Understandably, in the mass ratio of ammonium molybdate, nickel chloride, ferric chloride, and urea, nickel chloride can be 0.6 to 1.2, or 0.8 to 1.1, for example, 0.6, 0.7, 0.8, 0.9, 1, 1.1, 1.2, etc., or any range of two of the aforementioned values.

[0068] Understandably, in the mass ratio of ammonium molybdate, nickel chloride, ferric chloride, and urea, ferric chloride can be 0.05~0.1, or 0.06~0.08, for example, 0.05, 0.06, 0.07, 0.08, 0.09, 0.1, etc., or any range of two of the aforementioned values.

[0069] Understandably, in the mass ratio of ammonium molybdate, nickel chloride, ferric chloride, and urea, urea can be 0.1 to 0.3, or 0.2 to 0.26, for example, 0.1, 0.2, 0.26, 0.3, etc., or any range of two of the aforementioned values.

[0070] In some embodiments, in the method for preparing iron-nickel-molybdenum hydroxyl oxide, in the reaction step of mixing ammonium molybdate, nickel chloride and water, the reaction time is 1h to 5h, for example, 1h, 2h, 3h, 4h, 5h, etc., or it can be a range of any two of the aforementioned values.

[0071] In some embodiments, in the provided method for preparing iron-nickel-molybdenum hydroxyl oxide, an aqueous solution of ferric chloride is mixed with a suspension containing nickel molybdate and then stirred for 0.5 h to 1 h.

[0072] In some embodiments, in the method for preparing iron-nickel-molybdenum hydroxyl oxide, a suspension of iron-ion-modified nickel molybdate is mixed with an aqueous urea solution and stirred for 0.5 h to 1 h.

[0073] In some embodiments, in the provided method for preparing iron-nickel-molybdenum hydroxyl oxide, the mass ratio of ammonium molybdate to water is (0.9~1.7):60. For example, the mass ratio of ammonium molybdate to water can be 0.9:60, 1:60, 1.1:60, 1.2:60, 1.3:60, 1.4:60, 1.5:60, 1.6:60, 1.7:60, etc., or it can be any range of the two aforementioned ratios.

[0074] In some embodiments, in the provided method for preparing iron-nickel-molybdenum hydroxyl oxide, the concentration of ferric chloride in the aqueous solution is 1 mol / L to 2 mol / L, for example, 1 mol / L, 1.1 mol / L, 1.2 mol / L, 1.3 mol / L, 1.4 mol / L, 1.5 mol / L, 1.6 mol / L, 1.7 mol / L, 1.8 mol / L, 1.9 mol / L, 2 mol / L, etc., or it can be a range composed of any two of the aforementioned values.

[0075] In some embodiments, in the provided method for preparing iron-nickel-molybdenum hydroxyl oxide, the concentration of urea in the urea aqueous solution is 2 mol / L to 3 mol / L, for example, 2 mol / L, 2.1 mol / L, 2.2 mol / L, 2.3 mol / L, 2.4 mol / L, 2.5 mol / L, 2.6 mol / L, 2.7 mol / L, 2.8 mol / L, 2.9 mol / L, 3 mol / L, etc., or it can be a range composed of any two of the aforementioned values.

[0076] In some embodiments, the hydrothermal reaction temperature is 120°C to 130°C and the hydrothermal reaction time is 5 h to 15 h in the provided method for preparing iron-nickel-molybdenum hydroxy oxide.

[0077] In some embodiments, in the provided method for preparing iron-nickel-molybdenum hydroxyl oxide, the mass-volume ratio of the intermediate product to the alkaline solution is 100 mg: (100~200) mL. For example, the mass-volume ratio of the intermediate product to the alkaline solution is 100 mg: 100 mL, 100 mg: 150 mL, 100 mg: 200 mL, etc., or it can be a range of any two of the aforementioned ratios.

[0078] In some embodiments, the concentration of the alkaline solution in the provided method for preparing iron-nickel-molybdenum hydroxyl oxide is 1 mol / L to 2 mol / L.

[0079] In some embodiments, in the provided method for preparing iron-nickel-molybdenum hydroxyl oxide, the alkaline solution is one or both of sodium hydroxide aqueous solution and potassium hydroxide aqueous solution.

[0080] In some embodiments, the etching time in the provided method for preparing iron-nickel-molybdenum hydroxyl oxide is 20h to 60h, for example, 20h, 30h, 40h, 50h, 60h, etc., or it can be a range composed of any two of the aforementioned values.

[0081] In some implementations, solid-liquid separation is performed by vacuum filtration.

[0082] In some implementations, after solid-liquid separation and solid collection, the solid is further washed with deionized water.

[0083] In some embodiments, after etching, solid-liquid separation is performed, the solid is collected, and the collected solid is washed alternately with alkaline solution and deionized water, then dried to prepare iron-nickel-molybdenum hydroxyl oxide. In some embodiments, the drying temperature is 60°C to 70°C.

[0084] In some embodiments, a method for preparing an iron-nickel-molybdenum hydroxyl oxide is provided.

[0085] In some embodiments, the iron-nickel-molybdenum hydroxyl oxide is needle-shaped. In some embodiments, the length of the needle is 3μm to 6μm and the diameter is 75nm to 120nm. For example, the length is 3μm, 4μm, 5μm, 6μm, etc., or it can be any combination of the two aforementioned values. The diameter is 75nm, 80nm, 90nm, 100nm, 110nm, 120nm, etc., or it can be any combination of the two aforementioned values.

[0086] In some embodiments, the application of iron-nickel-molybdenum hydroxyl oxide is provided, which is used as a catalyst in anion exchange membrane water electrolysis hydrogen production systems.

[0087] In some embodiments, the electrolyte used in the anion exchange membrane water electrolysis hydrogen production system is an alkaline solution; in some embodiments, the alkaline solution is an aqueous solution of potassium hydroxide or sodium hydroxide; and in some embodiments, the concentration of the alkaline solution is 0.1 mol / L. -1 ~5mol L -1 .

[0088] The following are specific embodiments. They are intended to provide a more detailed description of this application to help those skilled in the art and researchers better understand it. The technical conditions described do not constitute any limitation on this application. Any modifications made within the scope of the claims of this application are protected by the claims.

[0089] Unless otherwise stated, all raw materials and reagents used in the following examples are commercially available or can be prepared by known methods. Experimental methods not specifying particular conditions in the examples were performed under conventional conditions, such as those described in literature, books, or methods recommended by the manufacturer.

[0090] Example 1

[0091] This embodiment provides an iron-nickel-molybdenum hydroxy oxide, prepared by the following method:

[0092] (1) Take FeCl3, NiCl2·6H2O and urea, and prepare 1 mol / L FeCl3, 1 mol / L NiCl2 and 2 mol / L urea solutions respectively.

[0093] (2) Add 0.91g of ammonium molybdate to 60g of deionized water and stir. At the same time, add 0.65g of NiCl2 solution and stir at 700rpm for 1 hour. Add 0.05g of FeCl3 solution to the above solution and stir for 0.5 hours. Then add 0.16g of urea solution and stir for 0.5 hours to obtain a mixture.

[0094] (3) The mixture obtained in step (2) was placed in a hydrothermal reactor for hydrothermal reaction at a temperature of 120°C for 12 hours. After the hydrothermal reaction was completed, the mixture was cooled to about 30°C and removed in time. It was then filtered and washed with deionized water to obtain the intermediate product Fe-NiMoO4.

[0095] (4) Add 100 mg of intermediate product to 100 mL of 1 mol / L KOH solution, stir and etch at 700 rpm for 24 h, filter, wash with 1 mol / L KOH and deionized water 5 times each, and dry at 60 °C for 6 h to obtain iron-nickel-molybdenum hydroxy oxide.

[0096] Four parallel experiments were conducted simultaneously. 0.3 g of iron-nickel-molybdenum hydroxyl oxide could be obtained in one preparation using four 100 mL hydrothermal reactors.

[0097] Example 2

[0098] This embodiment provides an iron-nickel-molybdenum hydroxyl oxide, which is prepared in a similar manner to that in Example 1, except that the content of ammonium molybdate is 1.29g, nickel chloride is 1.02g, ferric chloride is 0.08g, and urea is 0.26g.

[0099] Four parallel experiments were conducted simultaneously. One batch of iron-nickel-molybdenum hydroxyl oxide could be prepared using four 100mL hydrothermal reactors.

[0100] Using a 1000mL hydrothermal reactor for scale-up, four hydrothermal reactors can produce 10g of product per cycle. It can accommodate 400 membrane electrodes for use in a 10kW-level water electrolysis hydrogen production system.

[0101] Example 3

[0102] This embodiment provides an iron-nickel-molybdenum hydroxyl oxide, which is prepared in a similar way to that in Example 1, except that the content of ammonium molybdate is 1.69g, nickel chloride is 1.11g, ferric chloride is 0.10g, and urea is 0.28g.

[0103] Four parallel experiments were conducted simultaneously. Using four 100mL hydrothermal reactors, 0.95g of iron-nickel-molybdenum hydroxyl oxide could be obtained in a single preparation. The yield decreased with increasing raw material proportions.

[0104] Example 4

[0105] This embodiment provides an iron-nickel-molybdenum hydroxyl oxide, which is prepared in a similar manner to that in Example 1, except that the content of ammonium molybdate is 0.01g, nickel chloride is 0.5g, ferric chloride is 2g, and urea is 0.5g.

[0106] Four parallel experiments were conducted simultaneously. 0.1 g of iron-nickel-molybdenum hydroxyl oxide could be obtained in one preparation using four 100 mL hydrothermal reactors.

[0107] Example 5

[0108] This embodiment provides an iron-nickel-molybdenum hydroxyl oxide, prepared using a method similar to that in Example 2, except that 90 kg of deionized water, 2.535 kg of ammonium molybdate, 1.53 kg of nickel chloride, 0.12 kg of ferric chloride, and 0.39 kg of urea are used. The hydrothermal reaction is carried out in a 500L hydrothermal reactor. 4.5 kg of iron-nickel-molybdenum hydroxyl oxide is obtained.

[0109] Comparative Example 1

[0110] This comparative example provides an iron-nickel-molybdenum hydroxy oxide, which is prepared in a similar manner to that in Example 1, except that nickel nitrate is used instead of nickel chloride and ferric nitrate is used instead of ferric chloride.

[0111] Four parallel experiments were conducted simultaneously. 0.2 g of iron-nickel-molybdenum hydroxyl oxide could be obtained in one preparation using four 100 mL hydrothermal reactors.

[0112] Comparative Example 2

[0113] This comparative example provides an iron-nickel-molybdenum hydroxy oxide, which is prepared in a similar manner to that in Example 1. The difference is that in step (2), ammonium molybdate, deionized water, NiCl2 solution, FeCl3 solution and urea solution are mixed simultaneously.

[0114] Four parallel experiments were conducted simultaneously. 0.3 g of iron-nickel-molybdenum hydroxyl oxide could be obtained in one preparation using four 100 mL hydrothermal reactors.

[0115] Comparative Example 3

[0116] A method for preparing nickel-iron alloy / ferric molybdate hybrid nanomaterials includes the following steps:

[0117] Under magnetic stirring, 0.6844 g of NiCl2·6H2O, 0.2619 g of FeCl3·6H2O, and 0.1703 g of (NH4)6Mo7O were added. 24 • 4H₂O was dissolved in 160 mL of deionized water to form a green acidic solution; then, under continuous stirring, 1.0 g of urea was added to the solution and stirred uniformly for 10 min; the obtained homogeneous solution was evenly transferred to four 50 mL stainless steel autoclaves and reacted at 120 °C for 12 h in an electronic oven; after the reaction was completed and allowed to cool naturally to room temperature, the obtained yellow product was collected, washed three times with deionized water and ethanol respectively, and then dried in a vacuum oven at 60 °C for 12 h; finally, the above precursor was placed in a tube furnace and heated at 5 °C for 1 min under an Ar / H₂ (19:1) mixed atmosphere. -1 The temperature was increased to 500℃ for annealing and held at 500℃ for 1 hour to obtain nickel-iron alloy / iron molybdate hybrid nanomaterials with multiple interfaces and strong electronic correlation.

[0118] Comparative Example 4

[0119] A trimetallic oxide electrocatalyst based on iron-nickel-molybdenum is prepared by the following specific steps:

[0120] S1, take an area of ​​1×3cm 2The nickel foam was placed in a beaker and subjected to ultrasonic treatment at 100 kHz for 22 min in sequence with 1 mol / L hydrochloric acid, deionized water and anhydrous ethanol. Then it was placed in a vacuum furnace at 70 ℃ and dried for 2 h to obtain the treated nickel foam.

[0121] S2. Take 2.5 mmol of nickel chloride hexahydrate (NiCl2·6H2O) powder, 2.5 mmol of ferric chloride hexahydrate (FeCl3·6H2O) powder and 5 mmol of sodium molybdate dihydrate (Na2MoO4·2H2O) powder, add them to 35 mL of deionized water respectively, dissolve them, mix them at room temperature, and stir magnetically for 20 min to obtain a mixed solution.

[0122] S3. The treated nickel foam and the mixed solution were subjected to a solvothermal reaction in a polytetrafluoroethylene reactor at a temperature of 160°C for 7 hours. After the reaction was completed, a crude product was obtained.

[0123] S4. Cool the crude product to room temperature, wash it with deionized water and anhydrous ethanol, and dry it in a vacuum drying oven at 80°C for 14 hours to obtain the iron-nickel-molybdenum trimetallic oxide electrocatalyst.

[0124] 5×10cm 2 When nickel foam is placed in a 500mL hydrothermal reactor and the reaction is scaled up proportionally under the above conditions to prepare a trimetallic oxide electrocatalyst based on iron-nickel-molybdenum, uneven local growth and low catalyst loading uniformity occur, thus affecting catalytic performance. This can be a fatal flaw in large-scale hydrogen production equipment, impacting the entire lifespan of the equipment.

[0125] Because hydrothermal reactions require substrate materials, the area of ​​nickel foam (electrode) grown by hydrothermal methods is strictly limited. This production scale is only suitable for laboratory hydrogen production. In large-scale hydrogen production equipment, the electrocatalysts prepared by this method cannot be mass-produced and loaded into hydrogen production equipment due to production limitations, thus restricting its industrial application.

[0126] Comparative Example 5

[0127] This comparative example provides a method for preparing a supported oxygen evolution electrode with a nickel-iron buffer layer, the method comprising the following steps:

[0128] (1) The foamed nickel was ultrasonically cleaned with acetone for 30 min, ultrasonically cleaned with 0.1M hydrochloric acid for 30 min, and ultrasonically cleaned with ultrapure water for 15 min in sequence, and then dried to obtain the pretreated foamed nickel.

[0129] (2) The foamed nickel pretreated in step (1) was hydrothermally reacted at 150°C for 8 hours in a mixture of nickel chloride, ferric chloride and sodium molybdate. After cooling, it was taken out, washed and dried to obtain the foamed nickel loaded with nickel-iron-molybdenum precursor.

[0130] The concentration ratio of nickel chloride, ferric chloride, and sodium molybdate is 1:0.1:0.5, the concentration of nickel chloride is 10 mM, the concentration of ferric chloride is 1 mM, and the concentration of sodium molybdate is 5 mM.

[0131] (3) In a 1M NaOH solution, using the nickel foam with nickel-iron-molybdenum precursor loaded in step (2) as the working electrode and the graphite electrode as the auxiliary electrode, a periodic voltage is applied and activated at 25°C for 30 minutes to obtain the nickel foam with the nickel-iron buffer layer.

[0132] The periodic voltage range is ±3V, and the period of the periodic voltage is 1min;

[0133] The nickel-iron buffer layer has a porous micron-column array structure, and the loading capacity of the nickel-iron buffer layer is 11.9 mg / cm³. 2 The specific capacitance is 232 mF·cm. -2 ;

[0134] (4) In a mixture of ferric nitrate and nickel chloride, using the nickel foam with the nickel-iron buffer layer described in step (3) as the working electrode and the titanium-ruthenium electrode as the counter electrode, at 30 mA·cm -2 Electrodeposition was performed at a current density for 120 s, followed by rinsing with deionized water and drying to obtain the supported oxygen evolution electrode with a nickel-iron buffer layer.

[0135] The concentration of ferric nitrate and nickel chloride in the mixture is 0.1M.

[0136] In the process of preparing electrode materials by electrodeposition, when the area of ​​the nickel foam (electrode) is increased to 3cm×3.5cm, the resulting supported oxygen evolution electrode with a nickel-iron buffer layer will have problems such as uneven growth and easy detachment, catalyst peeling off the electrode surface during the test, and poor electrode stability.

[0137] In industrial production, the above reaction conditions need to be scaled up proportionally. Changes in electrode area will affect current density, so current density needs to be adjusted. However, the current density adjustment of large-area electrodes is uncontrollable. Therefore, the electrodeposition method limits the size of the electrode area and cannot achieve large-scale mass production.

[0138] Performance testing

[0139] (1) Scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS), and X-ray diffraction (XRD) detection

[0140] The prepared iron-nickel-molybdenum hydroxy oxides were detected by scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS), and X-ray diffraction (XRD).

[0141] To further investigate the microstructure of iron-nickel-molybdenum hydroxyl oxides, morphological analysis was performed using a scanning electron microscope (SEM). A Thermo Fisher Scientific SEM was used in this experiment. During sample preparation, the powdered sample was fixed onto a carbon conductive adhesive. Before imaging, the sample was purged with nitrogen to improve its observability. An energy dispersive spectroscopy (EDS) instrument (Oxford Xplore) was also used on the SEM to aid in observing the microstructure and determining the elemental composition of the sample. The accelerating voltage for surface scanning was 10.0 kV. These techniques provide crucial information on the morphology, crystal structure, and elemental distribution of iron-nickel-molybdenum hydroxyl oxides.

[0142] Figure 1 The image shows the SEM results of the iron-nickel-molybdenum hydroxyl oxide prepared in Example 2. Figure 1 As can be seen, the prepared product exhibits a good needle-like structure with uniform morphology and a size in the micrometer range. The iron-nickel-molybdenum hydroxyl oxide obtained in Example 3 shows a clear needle-like dispersion with a few clusters. The iron-nickel-molybdenum hydroxyl oxide obtained in Example 4 has a less obvious needle-like dispersion and more clusters, such as... Figure 2 As shown.

[0143] Figure 3 This is an EDS result diagram of the iron-nickel-molybdenum hydroxyl oxide prepared in Example 2, from... Figure 3 As can be seen, the elements are uniformly distributed.

[0144] Characterization was performed using a BRUKER D8 ADVANCE X-ray diffractometer. The X-ray source was Cu-Kα, and the rated voltage and rated current of the instrument were 40 kV and 40 mA, respectively. The 2θ angle range for XRD measurements of the samples was 10°–90°, and the scan rate was 10° / min. The results are as follows: Figure 4 As shown. Figure 4 The image shows the XRD peaks of pure iron-nickel-molybdenum hydroxyl oxide (FeNiMo) as a comparison. The image compares the FeNiMo hydroxyl oxide prepared in Example 2 with those prepared in Comparative Example 1. A comparison with the standard PDF card shows that the sample's diffraction peaks are sharp and narrow, indicating good crystallinity. X-ray diffraction (XRD) results show that the sample's diffraction pattern matches well with nickel molybdate (JCPDS # 40-0215). However, observation of the XRD reveals that the Fe crystal planes are not visible in the spectrum. This is because the amount of Fe doping is too small, resulting in a large difference in peak intensity that prevents them from appearing in the spectrum. We used EDS energy dispersive spectroscopy to confirm that Fe is homogeneously doped in the FeNiMo hydroxyl oxide.

[0145] (2) Linear scan voltammetry test

[0146] The products prepared in Examples 1-5 and Comparative Examples 1-3 were sprayed onto the membrane electrode and loaded into the AEMWE device. At a KOH concentration of 1 mol / L, the membrane electrode was subjected to a flow rate of 1 A / cm². 2 The performance is considered stable if the current density and temperature are stable at 60℃ for more than 300 hours; if there are fluctuations below 300 hours, the performance is considered poor and unstable. The test results are shown in Table 1.

[0147] Table 1

[0148]

[0149] The results in Table 1 show that the provided iron-nickel-molybdenum hydroxyl oxide exhibits excellent catalyst performance and good stability as a catalyst for anion exchange membrane water electrolyzers. While the product in the comparative example shows better stability, it suffers from higher cost, lower yield, and poorer catalytic performance.

[0150] Figure 5 Linear sweep voltammetric (LSV) curves of the products obtained in Example 2 and Comparative Example 1 are shown below. Figure 5 As can be seen, when the raw material for synthesis is changed from the conventional laboratory reagent nitrate to the industrial raw material chloride, the performance of the catalyst remains unchanged and maintains good performance. The electrode potential is controlled to change at a constant rate over time, and the current response through the working electrode is measured simultaneously, i.e., when the current density reaches 1 mA / cm². -2 At those times, the voltages were 1.62V and 1.65V respectively.

[0151] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0152] The embodiments described above are merely illustrative of several implementations of the present invention, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the invention. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these all fall within the protection scope of the present invention. Therefore, the protection scope of this invention should be determined by the appended claims, and the specification and drawings can be used to interpret the content of the claims.

Claims

1. A method for preparing an iron-nickel-molybdenum hydroxyl oxide, characterized in that, Includes the following steps: Ammonium molybdate, nickel chloride, and water are mixed and reacted to prepare a suspension containing nickel molybdate. A suspension of nickel molybdate containing iron ions was prepared by mixing an aqueous solution of ferric chloride with the suspension containing nickel molybdate. The suspension of the iron-modified nickel molybdate was mixed with an aqueous urea solution and subjected to a hydrothermal reaction. The intermediate product was obtained by solid-liquid separation. The intermediate product is mixed with an alkaline solution and etched to prepare the iron-nickel-molybdenum hydroxy oxide; The iron-nickel-molybdenum hydroxy oxide does not contain a base material.

2. The method for preparing iron-nickel-molybdenum hydroxyl oxide according to claim 1, characterized in that, The mass ratio of the ammonium molybdate, the nickel chloride, the ferric chloride, and the urea is (0.9~1.7):(0.6~1.2):(0.05~0.1):(0.1~0.3).

3. The method for preparing iron-nickel-molybdenum hydroxyl oxide according to claim 1, characterized in that, One or more of the following conditions must be met: (1) In the reaction step of mixing ammonium molybdate, nickel chloride and water, the reaction time is 1h~5h; (2) Mix the ferric chloride aqueous solution with the nickel molybdate suspension and stir for 0.5 h to 1 h; (3) The suspension of iron-modified nickel molybdate is mixed with urea aqueous solution and stirred for 0.5h to 1h.

4. The method for preparing iron-nickel-molybdenum hydroxyl oxide according to any one of claims 1 to 3, characterized in that, The mass ratio of the ammonium molybdate to the water is (0.9~1.7):

60.

5. The method for preparing iron-nickel-molybdenum hydroxyl oxide according to any one of claims 1 to 3, characterized in that, One or more of the following conditions must be met: (1) The concentration of ferric chloride in the ferric chloride aqueous solution is 1 mol / L to 2 mol / L; (2) The concentration of urea in the urea aqueous solution is 2 mol / L to 3 mol / L; (3) The temperature of the hydrothermal reaction is 120℃~130℃ and the time of the hydrothermal reaction is 5h~15h.

6. The method for preparing iron-nickel-molybdenum hydroxyl oxide according to any one of claims 1 to 3, characterized in that, One or more of the following conditions must be met: (1) The mass-to-volume ratio of the intermediate product to the alkaline solution is 100 mg: (100~200) mL; (2) The concentration of the alkaline solution is 1 mol / L to 2 mol / L; (3) The alkaline solution is one or both of sodium hydroxide aqueous solution and potassium hydroxide aqueous solution; (4) The etching time is 20h~60h.

7. An iron-nickel-molybdenum hydroxyl oxide prepared by the preparation method according to any one of claims 1 to 6, characterized in that, The iron-nickel-molybdenum hydroxyoxide is needle-shaped.

8. The iron-nickel-molybdenum hydroxyl oxide according to claim 7, characterized in that, The needle-like structure has a length of 3μm to 6μm and a diameter of 75nm to 120nm.

9. An application of the iron-nickel-molybdenum hydroxyl oxide as described in claim 7 or 8, characterized in that, The iron-nickel-molybdenum hydroxyoxide is used as a catalyst in anion exchange membrane water electrolysis hydrogen production systems.

10. The application according to claim 9, characterized in that, The electrolyte used in the anion exchange membrane water electrolysis hydrogen production system is an alkaline solution.

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