A NiMoO4 / Ni(OH)2@NiP x Layered structure catalysts, methods for their preparation and use

Abstract

The application discloses a kind of NiMoO4 / Ni (OH) 2@NiP x Layered structure catalyst and its preparation method and application.The preparation method of the catalyst comprises the following steps: step 1, cleaning treatment is carried out on a nickel substrate; step 2, a nickel molybdate (NiMoO4) precursor is synthesized on the nickel substrate by a hydrothermal method; step 3, a nickel hydroxide@nickel phosphide composite (Ni(OH)2@NiP x ) is grown on the surface of the NiMoO4 by an electrodeposition method.The catalyst has a three-dimensional layered structure, one-dimensional NiMoO4 micrometer / nanometer rods serve as support, two-dimensional Ni(OH)2 nanosheets are grown on the surface of the NiMoO4, and zero-dimensional NiP x nanoparticles are embedded in the Ni(OH)2 nanosheets.The catalyst exhibits excellent performance in a hydrogen evolution reaction, has high activity and good stability, and is suitable for clean hydrogen production.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of electrocatalysts, and particularly relates to a NiMoO4 / Ni(OH)2@NiP x Layered structure catalyst and preparation method and application thereof. BACKGROUND

[0002] Water splitting electrocatalysis technology is considered as a very promising clean hydrogen production method. In this process, the hydrogen evolution reaction (HER) is a key step, which requires the catalyst to have high catalytic activity, good stability and low cost. Although noble metal catalysts (such as platinum) exhibit excellent catalytic performance in the hydrogen evolution reaction, their high cost limits their large-scale application. In recent years, nickel phosphide (NiP x ) as a kind of non-noble metal catalyst with great potential, due to its good electronic structure and corrosion resistance, has attracted widespread attention. Nickel phosphide has similar electronic properties to platinum and exhibits high catalytic activity in electrocatalytic reactions, so it is considered as a powerful alternative to noble metal catalysts. Compared with noble metal catalysts, nickel phosphide not only has a significant cost advantage, but also has good stability, which makes it not easy to degrade in long-term electrocatalytic reactions, showing good application prospects.

[0003] However, as an electrocatalyst, the activity of nickel phosphide is still insufficient compared with noble metal catalysts. The structural design of nickel phosphide catalyst still faces many challenges, which limit its widespread application in practical applications. First of all, the structure of the catalyst not only affects the effective exposure of the active site, thereby limiting its catalytic efficiency, but also an unoptimized structure can lead to undesirable wettability and gas repellency of the catalyst. Specifically, insufficient contact of the catalyst with the electrolyte, hydrogen bubbles are easily accumulated on the surface of the catalyst, thereby hindering the reaction and affecting the smooth progress of the hydrogen evolution reaction. In addition, the powder-like nickel phosphide catalyst usually needs to use a binder when combined with the electrode, which not only reduces the conductivity of the catalyst, but also can cause a decrease in electrochemical performance. More seriously, the binder can degrade or fall off during long-term use, thereby reducing the effective active area of the catalyst and further reducing the catalytic efficiency. SUMMARY

[0004] To solve the above technical problems, the present application provides a NiMoO4 / Ni(OH)2@NiP x Layered structure catalyst and preparation method, which aims to solve the problems of insufficient exposure of active sites, poor hydrophilicity and gas repellency, and poor conductivity and stability due to the use of a binder in the prior art. The catalyst prepared by the present application has a unique three-dimensional layered structure, exhibits excellent hydrophilicity and gas repellency, and exhibits excellent catalytic performance and persistent stability in the hydrogen evolution reaction.

[0005] To achieve the above object, in one aspect, the present application provides a NiMoO4 / Ni(OH)2@NiP x The preparation method of the layered structure catalyst comprises the following steps:

[0006] Step 1, nickel substrate treatment: the nickel substrate is sequentially cleaned by ultrasonic cleaning with dilute hydrochloric acid, deionized water and ethanol to remove the surface oxide layer and oil stains, and finally naturally air-dried to obtain a clean nickel substrate.

[0007] Step 2, preparation of precursor NiMoO4: nickel salt and ammonium molybdate are dissolved in deionized water, and stirred until the solution is uniform. The treated nickel substrate in step 1 is placed in the solution and transferred to a high-pressure reaction kettle for hydrothermal reaction. The hydrothermal reaction temperature is 100-160°C, and the time is 4-14 h. After the reaction is completed, the nickel substrate is cooled to room temperature, cleaned with deionized water and ethanol, and dried in a 60°C oven to obtain the precursor NiMoO4.

[0008] This step forms a rod-like array structure of NiMoO4 with a large specific surface area on the nickel substrate through hydrothermal reaction, which helps to improve the subsequent loading capacity of active substances and serves as a fast channel for electron transfer in the hydrogen evolution reaction process.

[0009] Step 3, electrodeposition of Ni(OH)2@NiP x composite: nickel nitrate, sodium hypophosphite (NaH2PO2) and ammonium fluoride are dissolved in deionized water, and stirred until the solution is clear. The NiMoO4-loaded nickel substrate prepared in step 2 is used as the cathode, and an inert anode is used as the anode. Electrodeposition is carried out at a current density of 10-500 mA / cm 2 , a temperature of 20-80°C, and an electrodeposition time of 1-120 min. After electrodeposition is completed, the nickel substrate is removed, cleaned with deionized water and ethanol in sequence, and dried in a 60°C oven to obtain the NiMoO4 / Ni(OH)2@NiP x catalyst.

[0010] Further, the nickel salt in step 2 can be one or a mixture of nickel nitrate, nickel sulfate or nickel chloride.

[0011] Further, the concentration of nickel ions in step 2 is 0.01-0.2 mol / L, and the molar ratio of nickel to molybdenum is 1:0.5-3.

[0012] Further, the concentration of nickel ions in step 3 is 0.1-1.0 mol / L, and the molar ratio of nickel ions to ammonium fluoride is 1:1.0-3.0.

[0013] Further, the concentration of sodium hypophosphite in step 3 is 0.1-1.0 mol / L.

[0014] Further, the inert anode used in step 3 can be a titanium plating noble metal coating electrode, a titanium plating non-noble metal coating electrode or a graphite carbon rod.

[0015] In another aspect, the present application also provides a NiMoO4 / Ni(OH)2@NiP x The layered structure catalyst has a three-dimensional layered structure, wherein one-dimensional NiMoO4 micrometer / nanometer rods serve as supports, two-dimensional Ni(OH)2 nanosheets grow on the surface of the NiMoO4, and zero-dimensional nickel phosphide (NiP x ) nanoparticles are embedded in the Ni(OH)2 nanosheets, and the structure significantly improves the electrocatalytic hydrogen evolution performance of the catalyst through the synergistic effect of different dimensions.

[0016] In another aspect, the present application also provides a NiMoO4 / Ni(OH)2@NiP x The layered structure catalyst in the hydrogen evolution reaction.

[0017] The present application has the following beneficial effects:

[0018] The NiMoO4 / Ni(OH)2@NiPx catalyst provided by the present application has excellent hydrophilic performance (contact angle close to 0°) and good bubble repellency (bubble contact angle reaching 164°). The design of the three-dimensional layered structure effectively exposes more active sites, significantly improving the catalytic efficiency. When the current density is 10 mA cm⁻ 2 , the prepared catalyst exhibits a low hydrogen evolution overpotential of only 77 mV and can be stably operated at this current density for more than 100 hours, showing excellent stability. In addition, the catalyst is directly grown on a nickel substrate in a binder-free self-supporting manner, which avoids the negative impact of the binder on the conductivity and ensures excellent electrocatalytic performance. The use of low-cost non-noble metal raw materials further reduces the production cost of the catalyst, making it have a significant advantage in economy and having the potential for large-scale production. BRIEF DESCRIPTION OF DRAWINGS

[0019] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the drawings needed in the embodiments will be briefly introduced below. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can be obtained by those skilled in the art without creative labor.

[0020] Figure 1NiMoO4 / Ni(OH)2@NiP prepared for Example 1 of the present application x a scanning electron microscope image of

[0021] Figure 2 a transmission electron microscope image of NiMoO4 / Ni(OH)2@NiP prepared for Example 1 of the present application x

[0022] Figure 3 an X-ray powder diffraction pattern of NiMoO4 / Ni(OH)2@NiP prepared for Example 1 of the present application x

[0023] Figure 4 a water droplet contact angle and underwater bubble contact angle diagram of NiMoO4 / Ni(OH)2@NiP prepared for Example 1 of the present application x

[0024] Figure 5 a hydrogen evolution reaction performance diagram of NiMoO4 / Ni(OH)2@NiP x, Comparative Example 1, Comparative Example 2, and Comparative Example 3 prepared for Example 1 of the present application

[0025] Figure 6 a hydrogen evolution reaction stability test diagram of NiMoO4 / Ni(OH)2@NiP prepared for Example 1 of the present application x DETAILED DESCRIPTION

[0026] Various exemplary embodiments of the present application will now be described in detail, which should be considered to be merely illustrative in nature and are not to be considered as limiting the scope of the present application, and are understood to be a description of certain aspects, features, and embodiments of the present application.

[0027] It is to be understood that the terms used in the present application are merely used to describe particular embodiments and are not intended to limit the present application. In addition, for numerical ranges in the present application, it is understood that each intermediate value between the upper limit and the lower limit of the range is specifically disclosed. Each smaller range within the stated range and between any stated value or stated range and any other stated value or stated range is also encompassed within the present application. The upper and lower limits of these smaller ranges can be independently included or excluded from the range.

[0028] ​​​​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 application pertains, unless indicated otherwise. Although methods and materials similar or equivalent to those described herein can be used in the practice or testing of the present application, the preferred methods and materials are described. All publications mentioned in this specification are herein incorporated by reference to disclose and describe the methods and / or materials in connection with which the publications are cited. The citation of any reference is not an admission that it is prior art with respect to the present application. All literature and similar materials cited in this application, including but not limited to, patents, genetic sequences, and other documents, are hereby expressly incorporated by reference.

[0029] Many modifications and variations of the present application described in the specific embodiments of the application can be made by those skilled in the art without departing from the spirit or scope of the application. Other implementations of the application will be apparent to those skilled in the art from consideration of the specification and practice of the application disclosed herein. The specification and examples given are exemplary only.

[0030] As used herein, the terms "comprises", "comprising", "includes", "including", "has", "having", "contains", "containing", or variations thereof, are intended to be open-ended terms that mean inclusion, but not limited to, the listed materials and methods.

[0031] Example 1

[0032] Step 1, Nickel substrate treatment: Take a piece of nickel substrate with a size of 2 cm x 5 cm, and ultrasonic clean it in a 3 M dilute hydrochloric acid solution for 5 minutes to remove the surface oxide layer and impurities. Then, clean it with deionized water and anhydrous ethanol three times in turn, and dry it at room temperature to obtain a clean nickel substrate.

[0033] Step 2, Preparation of precursor NiMoO4: Dissolve 2.4 mmol of nickel nitrate (Ni(NO3)2·6H2O) and 0.6 mmol of ammonium molybdate ((NH4)6Mo7O 24 ·4H2O) in 80 mL of deionized water, and stir until the solution is uniform. Transfer the above solution to a 100 mL high-pressure reactor, and vertically immerse the pretreated nickel substrate into the solution. The concentration of nickel ions in the solution is 0.03 mol / L, and the molar ratio of nickel to molybdenum is 1:1.75. After sealing the high-pressure reactor, perform a hydrothermal reaction at 150°C for 5 hours. After the reaction is completed, cool it to room temperature, take out the nickel substrate, clean it with deionized water and ethanol, and dry it in an oven at 60°C to obtain a nickel substrate loaded with NiMoO4.

[0034] Step 3, Electrodeposition of Ni(OH)2@NiP xComposite: 20 mmol of nickel nitrate, 20 mmol of sodium hypophosphite and 25 mmol of ammonium fluoride were dissolved in 50 mL of deionized water, stirred until the solution was clear, the concentration of nickel ions in the solution was 0.4 mol / L, the concentration of sodium hypophosphite was 0.4 mol / L, and the concentration of ammonium fluoride was 0.5 mol / L. The NiMoO4-loaded nickel substrate prepared in step 2 was used as the cathode, and an inert graphite carbon rod was used as the anode. The deposition was carried out at 25°C for 6 minutes at a current density of 100 mA / cm 2 2, and the deposition was carried out at 25°C for 6 minutes at a current density of 100 mA / cm x The layered structure catalyst.

[0035] Example 2

[0036] Step 1, nickel substrate treatment: Take a piece of nickel substrate with a size of 2 cm × 5 cm, and ultrasonically clean it in a 3 M dilute hydrochloric acid solution for 5 minutes to remove the surface oxide layer and impurities. Then, clean it with deionized water and absolute ethanol three times in sequence, and dry it at room temperature to obtain a clean nickel substrate.

[0037] Step 2, preparation of precursor NiMoO4: Dissolve 3.2 mmol of nickel nitrate (Ni(NO3)2·6H2O) and 0.8 mmol of ammonium molybdate ((NH4)6Mo7O 24 ·4H2O) in 80 mL of deionized water, and stir until the solution is uniform. Transfer the above solution to a 100 mL high-pressure reaction kettle, and vertically immerse the pretreated nickel substrate in the solution. The concentration of nickel ions in the solution is 0.04 mol / L, and the molar ratio of nickel to molybdenum is 1:1.75. After sealing the high-pressure kettle, perform a hydrothermal reaction at 120°C for 8 hours. After the reaction is completed, cool to room temperature, remove the nickel substrate, clean it with deionized water and ethanol, and then dry it in a 60°C oven to obtain a NiMoO4-loaded nickel substrate.

[0038] Step 3, electrodeposition of Ni(OH)2@NiP x Composite: 20 mmol of nickel nitrate, 20 mmol of sodium hypophosphite and 25 mmol of ammonium fluoride were dissolved in 50 mL of deionized water, stirred until the solution was clear, the concentration of nickel ions in the solution was 0.4 mol / L, the concentration of sodium hypophosphite was 0.4 mol / L, and the concentration of ammonium fluoride was 0.5 mol / L. The NiMoO4-loaded nickel substrate prepared in step 2 was used as the cathode, and an inert graphite carbon rod was used as the anode. The deposition was carried out at 25°C for 6 minutes at a current density of 100 mA / cm 2at 25 °C for 3 min. After deposition, the cathode was taken out, washed with deionized water and anhydrous ethanol in turn and dried to obtain NiMoO4 / Ni(OH)2@NiP x Layered structure catalyst.

[0039] Example 3

[0040] Step 1, nickel substrate treatment: take a piece of nickel substrate with a size of 2 cm x 5 cm, ultrasonic clean it in 3 M dilute hydrochloric acid solution for 5 min to remove the surface oxide layer and impurities. Then, wash it with deionized water and anhydrous ethanol for three times in turn and dry it at room temperature to obtain a clean nickel substrate.

[0041] Step 2, preparation of precursor NiMoO4: dissolve 1.6 mmol of nickel nitrate (Ni(NO3)2·6H2O) and 0.4 mmol of ammonium molybdate ((NH4)6Mo7O 24 ·4H2O) in 80 mL of deionized water and stir until the solution is uniform. Transfer the above solution to a 100 mL high-pressure reaction kettle and vertically immerse the pretreated nickel substrate in the solution. The concentration of nickel ions in the solution is 0.02 mol / L and the molar ratio of nickel to molybdenum is 1:1.75. After sealing the high-pressure kettle, perform hydrothermal reaction at 120 °C for 12 hours. After the reaction, cool to room temperature, take out the nickel substrate, wash it with deionized water and ethanol, and dry it in a 60 °C oven to obtain a nickel substrate loaded with NiMoO4.

[0042] Step 3, electrodeposition of Ni(OH)2@NiP x composite: dissolve 30 mmol of nickel nitrate, 20 mmol of sodium hypophosphite and 25 mmol of ammonium fluoride in 50 mL of deionized water, stir until the solution is clear, and the concentration of nickel ions in the solution is 0.6 mol / L, the concentration of sodium hypophosphite is 0.4 mol / L, and the concentration of ammonium fluoride is 0.5 mol / L. Take the nickel substrate loaded with NiMoO4 prepared in step 2 as the cathode and an inert graphite carbon rod as the anode. Under the condition of a current density of 50 mA / cm 2 at 25 °C for 12 min. After deposition, the cathode was taken out, washed with deionized water and anhydrous ethanol in turn and dried to obtain NiMoO4 / Ni(OH)2@NiP x Layered structure catalyst.

[0043] Example 4

[0044] Step 1, Nickel substrate treatment: Take a piece of nickel substrate with a size of 2 cm x 5 cm, and ultrasonically clean it in a 3 M dilute hydrochloric acid solution for 5 minutes to remove the surface oxide layer and impurities. Then, clean it with deionized water and anhydrous ethanol three times in turn, and dry it at room temperature to obtain a clean nickel substrate.

[0045] Step 2, Preparation of precursor NiMoO4: Dissolve 2.4 mmol of nickel nitrate (Ni(NO3)2·6H2O) and 0.6 mmol of ammonium molybdate ((NH4)6Mo7O 24 ·4H2O) in 80 mL of deionized water, and stir until the solution is uniform. Transfer the above solution to a 100 mL high-pressure reactor, and vertically immerse the pretreated nickel substrate into the solution. The concentration of nickel ions in the solution is 0.03 mol / L, and the molar ratio of nickel to molybdenum is 1:1.75. After sealing the autoclave, perform hydrothermal reaction at 120°C for 8 hours. After the reaction is completed, cool to room temperature, remove the nickel substrate, and clean it with deionized water and ethanol, then dry it in an oven at 60°C to obtain a nickel substrate loaded with NiMoO4.

[0046] Step 3, Electrodeposition of Ni(OH)2@NiP x composite: Dissolve 10 mmol of nickel nitrate, 10 mmol of sodium hypophosphite, and 15 mmol of ammonium fluoride in 50 mL of deionized water, and stir until the solution is clear. The concentration of nickel ions in the solution is 0.2 mol / L, the concentration of sodium hypophosphite is 0.2 mol / L, and the concentration of ammonium fluoride is 0.3 mol / L. Use the nickel substrate loaded with NiMoO4 prepared in Step 2 as the cathode, and a titanium-ruthenium electrode as the anode. Under a current density of 10 mA / cm 2 , deposit at a constant current for 60 minutes at 50°C. After deposition is complete, remove the cathode, clean it with deionized water and anhydrous ethanol, and dry it to obtain a NiMoO4 / Ni(OH)2@NiP x layered structure catalyst.

[0047] Physical characterization: The NiMoO4 / Ni(OH)2@NiP x layered structure catalyst obtained in Example 1 was physically characterized, and the results are as follows:

[0048] The scanning electron microscope image of the NiMoO4 / Ni(OH)2@NiP x composite shows a micrometer / nanometer rod array structure with a diameter of several micrometers, a rough surface, and a large number of intertwined nanosheets with a size of about 30-50 nanometers. Figure 1 Figure 2 ​Further analysis revealed the growth of numerous nanosheet structures on the nanorod surface. In magnified regions 1 and 2, lattice fringes corresponding to the Ni(111) crystal plane were clearly visible with a spacing of 0.205 nm, indicating that NiP was embedded on the nanosheet surface. x Nanoparticles. X-ray diffraction pattern shows ( Figure 3 The sample diffraction peaks mainly correspond to the characteristic peaks of NiMoO4 (PDF#45-0142), as well as a weak Ni(OH)2 peak, indicating that Ni(OH)2 exhibits amorphous characteristics. Furthermore, the relative contents of NiMoO4 and Ni(OH)2 are relatively high, while NiP... x The presence of these elements is relatively limited, therefore they did not clearly appear in the XRD patterns corresponding to NiP. x The diffraction peaks.

[0049] Figure 4 (a) and (b) show the bare nickel substrate and NiMoO4 / Ni(OH)2@NiP, respectively. x The water contact angle of the catalyst was measured. For the bare nickel substrate, the water contact angle was 136.8°, indicating significant hydrophobicity of the surface. Meanwhile, the NiMoO4 / Ni(OH)2@NiP catalyst exhibited a similar water contact angle. x Its water contact angle is close to 0°, indicating that it has excellent hydrophilicity and can fully contact water, thereby improving the wettability of the electrolyte and helping to improve the activity of the catalyst. Figure 4 (c) and (d) are NiMoO4 / Ni(OH)2@NiP, respectively. x Underwater bubble contact angle test results for the catalyst. The bubble contact angle of the bare nickel substrate is 147.5°, indicating that it has a certain degree of gas-repellency underwater; while NiMoO4 / Ni(OH)2@NiP x The bubble contact angle further increases to 164.6°, exhibiting excellent gas-repellent properties. This property can effectively prevent the accumulation of bubbles on the catalyst surface during hydrogen evolution, reduce the blockage of active sites, and thus improve the efficiency of the hydrogen evolution reaction. In summary, NiMoO4 / Ni(OH)2@NiP x With its three-dimensional layered structure, the catalyst exhibits excellent hydrophilicity and gas-repellency. These properties effectively optimize the contact between the catalyst and the electrolyte and the release process of hydrogen bubbles, thus giving it outstanding catalytic performance in the electrocatalytic hydrogen evolution reaction.

[0050] Application in the hydrogen evolution reaction:

[0051] The NiMoO4 / Ni(OH)2@NiP prepared in Example 1 xThe activity and stability of the catalyst for the hydrogen evolution reaction were tested, and the results are as follows: (1) Activity test: The NiMoO4 / Ni(OH)2@NiP catalyst was evaluated in 1 M KOH solution using a standard three-electrode system. x The HER catalytic performance was assessed based on the polarization curves obtained using linear sweep voltammetry (LSV). Figure 5 The results show that this catalyst requires only 77 mV overpotential to drive 10 mA / cm² in the hydrogen evolution reaction. 2 The current density.

[0052] (2) Stability test: at -10 mA / cm 2 At the specified current density, the catalyst can operate stably for 100 hours with almost no activity degradation. Figure 6 ).

[0053] Comparative Example 1

[0054] The difference from Example 1 is that sodium hypophosphite was not added to the electrolyte used in step 3, resulting in a nickel molybdate / nickel hydroxide composite catalyst (NiMoO4 / Ni(OH)2) grown on a nickel substrate. Electrochemical activity tests showed that at 10 mA / cm², [the catalyst exhibited good performance]. 2 At a current density of 127 mV, the overpotential required for the hydrogen evolution reaction is 127 mV. Figure 5 The yield is significantly higher than that of NiMoO4 / Ni(OH)2@NiP prepared in Example 1. x Catalyst (77 mV).

[0055] Comparative Example 2

[0056] The difference from Example 1 is that the nickel substrate pretreated in step 1 is not subjected to step 2, but is directly used as the cathode in step 3, resulting in a nickel hydroxide@nickel phosphide composite catalyst (Ni(OH)2@NiP) grown on the nickel substrate. X Electrochemical activity tests showed that at 10 mA / cm², 2 At a current density of 203 mV, the overpotential required for the hydrogen evolution reaction is 203 mV. Figure 5 The yield is significantly higher than that of NiMoO4 / Ni(OH)2@NiP prepared in Example 1. x Catalyst (77 mV).

[0057] Comparative Example 3

[0058] The difference from Example 1 is that the NiMoO4 prepared in step 2 is not subjected to subsequent electrodeposition of Ni(OH)2@NiP. x The composite, i.e., without step 3, remains the same. A nickel molybdate (NiMoO4) catalyst grown on a nickel substrate is obtained. Electrochemical activity tests show that at 10 mA / cm²...2 At a current density of 266 mV, the overpotential required for the hydrogen evolution reaction is 266 mV. Figure 5 The yield is significantly higher than that of NiMoO4 / Ni(OH)2@NiP prepared in Example 1. x Catalyst (77 mV).

[0059] In addition, such as Figure 5 As shown in c, the NiMoO4 / Ni(OH)2@NiP prepared in Example 1 x Compared to the catalysts in Comparative Examples 1, 2, and 3, the catalyst exhibits a lower Tafel slope (58.6 mV / dec), indicating a more rapid hydrogen evolution reaction kinetic. Meanwhile, as... Figure 5 d shows that the catalyst also exhibits the largest electrochemical active surface area (70 mF / cm²). 2 This indicates that the three-dimensional hierarchical structure is beneficial for the exposure of active sites. These results suggest that NiMoO4 / Ni(OH)2@NiP x Layered catalysts exhibit excellent performance in hydrogen evolution reactions and have broad application prospects.

[0060] The embodiments described above are merely preferred embodiments of the present invention and are not intended to limit the scope of the present invention. Various modifications and improvements made by those skilled in the art to the technical solutions of the present invention without departing from the spirit of the present invention should fall within the protection scope defined by the claims of the present invention.

Claims

1. A NiMo04 / Ni(OH)2@NiP x A method for preparing a layered structure catalyst, characterized by, The method comprises the following steps: Step 1, nickel substrate treatment: the nickel substrate is sequentially cleaned by ultrasonic cleaning with dilute hydrochloric acid, deionized water and ethanol, and then naturally dried after removing the surface oxide layer and oil stains; Step 2, preparation of precursor NiMoO4: nickel salt and ammonium molybdate are dissolved in deionized water, and the solution is stirred until uniform; the nickel substrate treated in step 1 is placed in the solution, and then transferred to a high-pressure reaction kettle for hydrothermal reaction; the hydrothermal reaction temperature is 100-160°C, and the time is 4-14 h; after the reaction is completed, the nickel substrate is taken out, cleaned with deionized water and ethanol, and dried in a 60°C oven to obtain the precursor NiMoO4; Step 3, electrodeposition of Ni(OH)2@NiP x Composite: dissolve nickel nitrate, ammonium fluoride and sodium hypophosphite in deionized water, stir until the solution is clear, take the NiMoO4-loaded nickel substrate prepared in step 2 as the working electrode, inert anode as the anode, electrodeposition, current density is 10~500 mA / cm 2 , temperature is 20~80 ℃, electrodeposition time is 1~120 min, after electrodeposition, take out the nickel substrate, wash with deionized water and ethanol in turn, and dry in a 60°C oven to obtain NiMoO4 / Ni(OH)2@NiP x catalyst.

2. The production method according to claim 1, characterized by, In step 2, the nickel salt is one or a mixture of nickel chloride, nickel sulfate or nickel nitrate, the concentration of nickel ions is 0.01-0.2 mol / L, and the molar ratio of nickel to molybdenum is 1:0.5-3.

3. The production method according to claim 1, characterized by, In step 3, the concentration of nickel nitrate is 0.1-1.0 mol / L, and the molar ratio of nickel ions to ammonium fluoride is 1:1.0-3.

0.

4. The production method according to claim 1, characterized by, In step 3, the concentration of sodium hypophosphite is 0.1-1.0 mol / L.

5. The preparation method according to claim 1, characterized in that, In step 3, the inert anode is a titanium electrode coated with a noble metal coating, a titanium electrode coated with a non-noble metal coating or a graphite carbon rod.

6. NiMo04 / Ni(OH)2@NiP prepared by the preparation method according to any one of claims 1-5 x The layered structure catalyst is characterized in that, The catalyst has a three-dimensional layered structure, wherein the one-dimensional layered structure is NiMoO4 micro / nanorod as support, the two-dimensional layered structure is Ni(OH)2 nanosheet grown on the surface of NiMoO4, and the zero-dimensional layered structure is NiP x The nanoparticles are embedded on the Ni(OH)2 nanosheet.

7. A NiMo04 / Ni(OH)2@NiP as claimed in claim 6 x Use of layered structure catalysts in hydrogen evolution reactions.

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