Preparation and application of foamed nickel layered supported cobalt tungsten oxide catalyst for efficient water decomposition

Abstract

The invention discloses preparation and application of a foamed nickel layered supported cobalt tungsten oxide catalyst for efficient water decomposition, and belongs to the technical field of electrochemical catalysis. Nickel foam (NF) is selected as a substrate, two cobalt oxides with different morphologies are sequentially grown through electrochemical deposition, ComCo3O4 serves as a first layer and can tightly wrap the NF, so that the NF is not subjected to anodic corrosion dissolution in a harsh acid medium, AcCo3O4 serves as a second layer, nano-sheet-shaped Co3O4 has good OER activity, and in addition, the NF is not subjected to anodic corrosion dissolution in the harsh acid medium. The WxOy / AcCo3O4 / ComCo3O4 / NF prepared by the method has the advantages that the WxOy / AcCo3O4 / ComCo3O4 / NF prepared by the method is low in overpotential and good in stability due to the fact that the WxOy / AcCo3O4 / ComCo3O4 / NF prepared by the aid of the method has the advantages that more growth sites are provided for the tungsten oxide by the aid of the large specific surface area, and the tungsten oxide is finally electrically deposited on the AcCo3O4.

Description

Technical Field

[0001] The present invention belongs to the technical field of electrochemical catalysis, and more specifically relates to the preparation and application of a foamed nickel layered loaded cobalt-tungsten oxide catalyst for efficient water decomposition. Background Art

[0002] Hydrogen energy has a high calorific value, about three times that of petroleum, making it an ideal substitute for fossil fuels. In addition, hydrogen does not produce any harmful or greenhouse gases after combustion. Electrocatalytic water electrolysis is one of the most promising strategies to meet humanity's future energy needs. Among different water electrolysis and oxygen evolution reaction hydrogen production technologies, proton exchange membrane water electrolysis has advantages in productivity, energy stability, and cost compared with other hydrogen production technologies. However, the efficient and sustainable large-scale production of hydrogen through proton exchange membranes still faces huge challenges, namely, there are no stable and cheap OER (oxygen evolution reaction) catalysts that can work at high current densities. Precious metal-based catalysts such as Ru-based and Ir-based catalysts have shown good stability and activity, but they still suffer from metal dissolution in the acidic medium inherent to the lattice oxygen evolution reaction mechanism. Therefore, there is an urgent need to develop effective and stable noble metal-free anode oxygen evolution catalysts for proton exchange membranes.

[0003] Various 3d transition metal oxides and their derivatives have the advantages of high abundance and low cost, and have received widespread attention as OER candidates. Among them, cobalt-based oxides have good OER activity in acidic media. The OER of cobalt-based oxides is considered to be one of the most promising OER candidates. According to theoretical calculations, the OER activity of cobalt-based oxides should be comparable to that of ruthenium-based and iridium-based oxides. However, Co3O4 exhibits high overpotential and instability under harsh OER conditions, especially in acidic media with high oxidation potential. This expected activity is challenged by the limited stability of cobalt oxides in acid. How to prepare highly active and stable cobalt-based anodic oxygen evolution catalysts remains a huge challenge. Summary of the Invention

[0004] The purpose of the present invention is to provide a preparation and application of a nickel foam layered loaded cobalt tungsten oxide catalyst for efficient water decomposition, so as to solve the problems existing in the above-mentioned prior art and realize the preparation of a cobalt-based anodic oxygen evolution catalyst with high activity and high stability.

[0005] To achieve the above object, the present invention provides the following solutions:

[0006] One of the technical solutions of the present invention is to provide a method for preparing a nickel foam layered loaded cobalt-tungsten oxide catalyst for efficient water splitting, comprising the following steps:

[0007] S1, sequentially subjecting nickel foam to electrochemical deposition using a cobalt source and boric acid as an electroplating solution, oxidation using a potassium hydroxide solution as an electroplating solution, and calcination to obtain ComCo3O4 / NF;

[0008] S2, sequentially subjecting the ComCo3O4 / NF to electrochemical deposition treatment using a cobalt source and polyvinyl pyrrolidone as an electroplating solution, and calcining to obtain AcCo3O4 / ComCo3O4 / NF;

[0009] S3, the AcCo3O4 / ComCo3O4 / NF is subjected to electrochemical deposition treatment using a tungsten source as an electroplating solution and calcined in sequence to obtain the foamed nickel layered loaded cobalt tungsten oxide catalyst for efficient water decomposition, denoted as W x O y / AcCo3O4 / ComCo3O4 / NF.

[0010] The present invention involves "W x O y " represents tungsten oxide, where x and y are the atomic ratios of tungsten and oxygen, including WO3 (tungsten trioxide), W2O5 (tungsten pentoxide), etc.

[0011] Preferably, in step S1, the electroplating solution is added in the form of an aqueous solution; in the electroplating solution, the concentration of the cobalt source is 0.1-0.2 mol / L, and the concentration of the acid reagent is 0.5-0.7 mol / L; the acid reagent includes boric acid and / or oxalic acid.

[0012] In step S1, the acid reagent is used to adjust the pH of the electroplating solution, and the potassium hydroxide solution is used to provide an alkaline environment so that the surface of the electrode sheet obtained by the electrochemical deposition treatment in step S1 can be oxidized into cobalt hydroxide.

[0013] Preferably, in step S1, the deposition current of the electrochemical deposition treatment is 15 to 20 mA, and the deposition time is 60 to 90 min; the concentration of the potassium hydroxide solution is 0.5 to 1 mol / L, and the oxidation current is 3 to 6 mA; the heating rate of the calcination is 5°C / min, the temperature is 500°C, and the holding time is 3 to 5 h.

[0014] Preferably, in step S2, the cobalt source includes cobalt nitrate and / or cobalt sulfate; the electroplating solution is added in the form of an aqueous solution; in the electroplating solution, the concentration of the cobalt source is 0.05-0.1 mol / L, and the concentration of polyvinyl pyrrolidone is 1-2 g / L.

[0015] In step S2 , polyvinyl pyrrolidone acts as a surfactant, which can cause cobalt ions to precipitate from the solution in the form of nano-sheet-shaped cobalt compounds.

[0016] Preferably, in step S2, the deposition current of the electrochemical deposition treatment is 3-6 mA, and the deposition time is 30-45 min; the heating rate of the calcination is 5° C. / min, the temperature is 350° C., and the holding time is 3-5 h.

[0017] Preferably, in step S3, the tungsten source includes sodium tungstate and / or potassium tungstate; the electroplating solution is added in the form of an aqueous solution; and the concentration of sodium tungstate in the electroplating solution is 0.1-0.5 mol / L.

[0018] Preferably, in step S3, the deposition current of the electrochemical deposition treatment is 10-15 mA, and the deposition time is 20-30 min; the heating rate of the calcination is 5° C. / min, the temperature is 350° C., and the holding time is 3-5 h.

[0019] The second technical solution of the present invention is to provide a foamed nickel layered loaded cobalt-tungsten oxide catalyst for efficient water decomposition prepared by the above preparation method.

[0020] The third technical solution of the present invention is to provide the application of the above-mentioned nickel foam layered loaded cobalt tungsten oxide catalyst for efficient water decomposition in hydrogen production by electrolysis of water.

[0021] The fourth technical solution of the present invention is to provide a method for improving the effect and stability of hydrogen production by electrolysis of water, comprising the following steps:

[0022] Water electrolysis reaction was carried out in a three-electrode system using the nickel foam layered loaded with cobalt tungsten oxide catalyst for efficient water decomposition as a working electrode, a platinum sheet as a counter electrode, a saturated calomel electrode as a reference electrode, and a 0.5 mol / L H2SO4 solution as an electrolyte.

[0023] The technical principles of the present invention are as follows:

[0024] The present invention uses nickel foam (NF) as a substrate and sequentially grows two cobalt oxides with different morphologies by electrochemical deposition. ComCo3O4 is the first layer, which can tightly wrap the NF to prevent anodic corrosion and dissolution of the NF in harsh acidic media. AcCo3O4 is the second layer. The nanosheet-shaped Co3O4 itself has good OER activity. In addition, the large specific surface area also provides more growth sites for tungsten oxide. Finally, tungsten oxide is electrodeposited on AcCo3O4. W prepared by this method x O y / AcCo3O4 / ComCo3O4 / NF has low overpotential and good stability.

[0025] The present invention discloses the following technical effects:

[0026] 1. The catalyst preparation method described in this invention utilizes a simple process combining electrochemical deposition and calcination, eliminating the need for complex equipment and demanding reaction conditions. First, electrochemical deposition, under a mild reaction environment, uniformly deposits the target substance on the substrate surface using only electrical energy. Subsequently, the substrate is calcined in a conventional muffle furnace. The entire process is straightforward, with readily available raw materials. This process eliminates the need for specialized technicians to perform lengthy operations, significantly lowering the production barrier and demonstrating the method's high feasibility and practicality.

[0027] 2. The catalyst of the present invention innovatively adopts a multi-layer composite structure design, cleverly integrating cobalt oxides of different morphologies to construct a microscopic system with synergistic performance. The dense cobalt tetroxide protects the base nickel foam from anode corrosion and damage to the overall structure of the material. The three-dimensional staggered arrangement of nano-sheet cobalt tetroxide creates a large amount of space, which provides ideal growth sites and attachment space for the subsequent growth of tungsten oxide. Through this design, the material is optimized in both the quality and quantity of active sites, which not only ensures the catalytic efficiency of a single active site, but also expands the reaction area by increasing the number of sites, ultimately achieving an overall improvement in performance.

[0028] 3. The catalyst of the present invention uses transition elements with abundant reserves and low price in the earth's crust as raw materials. The catalyst is 2 At a current density of 1.5 GHz, the catalyst exhibits an ultra-low overpotential of only 266 mV, significantly outperforming most similar non-precious metal materials. Constant current testing has confirmed that the catalyst maintains structural integrity and catalytic activity after operating continuously in strong acid for over 12 hours, demonstrating excellent corrosion and attenuation resistance. This approach, combined with lower raw material costs and optimized energy consumption, effectively reduces the cost of hydrogen production from water electrolysis. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 ComCo3O4 / NF, AcCo3O4 / ComCo3O4 / NF, and W obtained in Example 1 x O y XRD pattern of / AcCo3O4 / ComCo3O4 / NF;

[0030] Figure 2 ComCo3O4 / NF, AcCo3O4 / ComCo3O4 / NF, and W obtained in Example 1 x O y Nitrogen isothermal adsorption-desorption curves and specific surface area results of / AcCo3O4 / ComCo3O4 / NF;

[0031] Figure 3ComCo3O4 / NF, AcCo3O4 / ComCo3O4 / NF, and W obtained in Example 1 x O y SEM images of / AcCo3O4 / ComCo3O4 / NF, where a is ComCo3O4 / NF, b is AcCo3O4 / ComCo3O4 / NF, and c is W x O y / AcCo3O4 / ComCo3O4 / NF, d is W x O y Cross-sectional SEM image of / AcCo3O4 / ComCo3O4 / NF;

[0032] Figure 4 W obtained in Example 1 x O y Raman spectrum and X-ray photoelectron spectroscopy of / AcCo3O4 / ComCo3O4 / NF;

[0033] Figure 5 The electrochemically active surface area (ECSA) test results of nickel foam loaded with different cobalt-tungsten oxides;

[0034] Figure 6 The electrochemical impedance spectroscopy (EIS) test results of nickel foam materials with different cobalt-tungsten oxide loading sequences are shown below;

[0035] Figure 7 The linear voltammetric curves of nickel foam loaded with different cobalt-tungsten oxide materials and their stability test results in acidic medium. DETAILED DESCRIPTION

[0036] Various exemplary embodiments of the present invention will now be described in detail. This detailed description should not be considered as limiting the present invention, but rather as a more detailed description of certain aspects, features, and embodiments of the present invention.

[0037] It should be understood that the terms described herein are intended only to describe particular embodiments and are not intended to limit the present invention. In addition, for numerical ranges herein, it should be understood that each intermediate value between the upper and lower limits of the range is also specifically disclosed. The intermediate value within any stated value or stated range, and each smaller range between any other stated value or intermediate value within the stated range, is also encompassed within the present invention. The upper and lower limits of these smaller ranges may be independently included or excluded within the scope.

[0038] Unless otherwise indicated, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the art. Although only preferred methods and materials are described herein, any methods and materials similar or equivalent to those described herein may also be used in the practice or testing of the present invention. All documents mentioned in this specification are incorporated by reference to disclose and describe the methods and / or materials associated with the documents. In the event of any conflict with any incorporated document, the contents of this specification shall prevail.

[0039] It will be apparent to those skilled in the art that various modifications and variations may be made to the specific embodiments described herein without departing from the scope or spirit of the invention. Other embodiments will be apparent to those skilled in the art from the description of the invention. The description and examples are intended to be illustrative only.

[0040] The words “include,” “including,” “have,” “contain,” etc. used in this document are open-ended terms, meaning including but not limited to.

[0041] It should be pointed out that the matters not described in detail in the present invention are conventional operating means in this field and are not the focus of the present invention.

[0042] Unless otherwise specified, the raw materials used in the following examples and comparative examples of the present invention are all commercially available products, and the sources of the commercially available products do not affect the technical effects of the present invention.

[0043] The nickel foam of the present invention was purchased from Baiyida Electronic New Materials Business Department in Changpu Town, Kunshan.

[0044] Example 1

[0045] This embodiment provides a method for preparing a nickel foam layered loaded cobalt-tungsten oxide catalyst, the steps of which are as follows:

[0046] (1) Preparation of ComCo3O4 / NF

[0047] a. Dissolve 40g Co(NO3)2·6H2O and 40g H3BO3 in 1L deionized water to obtain a plating solution, take out 30mL in a beaker, and then 2 Nickel foam is used as the working electrode with an area of ​​1×2 cm 2 The carbon sheet counter electrode was deposited at a deposition current of 15 mA for 60 minutes, and then naturally dried.

[0048] b. The electrode sheet is used as the working electrode, with an area of ​​1×2cm 2 The carbon sheet was used as the counter electrode and was completely oxidized in a 1 mol / L potassium hydroxide solution with an oxidation current of 3 mA and a complete oxidation time of 60 min.

[0049] c. The obtained electrode sheet was placed in a muffle furnace and heated to 500°C at a heating rate of 5°C / min and calcined for 3h to prepare ComCo3O4 / NF.

[0050] (2) Preparation of AcCo3O4 / ComCo3O4 / NF

[0051] a. Dissolve 28g Co(NO3)2·6H2O and 1g polyvinylpyrrolidone (PVP) in 1L deionized water to prepare the plating solution. Take out 30mL and place it in a beaker. Use ComCo3O4 / NF as the working electrode with an area of ​​1×2cm 2 The carbon sheet was used as the counter electrode, and the deposition was carried out in the plating solution for 30 minutes with a deposition current of 3 mA.

[0052] b. The obtained electrode sheet was placed in a muffle furnace and heated to 350°C at a heating rate of 5°C / min and calcined for 3h to prepare AcCo3O4 / ComCo3O4 / NF.

[0053] (3)W x O y Preparation of / AcCo3O4 / ComCo3O4 / NF

[0054] a. The plating solution is 0.1 mol / L sodium tungstate solution. Take out 30 mL and put it into a beaker. Use AcCo3O4 / ComCo3O4 / NF as the working electrode with an area of ​​1×2 cm 2 The carbon sheet was used as the counter electrode and deposited in the plating solution for 20 minutes with a deposition current of 10 mA.

[0055] b. The obtained electrode sheet was placed in a muffle furnace and heated to 350°C at a heating rate of 5°C / min and calcined for 3h to prepare W x O y / AcCo3O4 / ComCo3O4 / NF.

[0056] Comparative Example 1 (Changing the Deposition Order of Cobalt Tungsten Oxide)

[0057] (1)W x O y Preparation of / ComCo3O4 / NF

[0058] a. ComCo3O4 / NF prepared in Example 1 was used as the working electrode, the carbon sheet was used as the counter electrode, and the electroplating solution was 0.1 mol / L sodium tungstate solution. 30 mL was taken out and placed in a beaker. The solution was deposited for 20 min at a deposition current of 10 mA.

[0059] b. The obtained electrode sheet was placed in a muffle furnace and heated to 350°C at a heating rate of 5°C / min and calcined for 3h to prepare W x O y / ComCo3O4 / NF.

[0060] Comparative Example 2

[0061] (1)AcCo3O4 / W x O y Preparation of / ComCo3O4 / NF

[0062] a. W prepared in Comparative Example 1 x O y / ComCo3O4 / NF was used as the working electrode and the carbon sheet as the counter electrode. 28 g of Co(NO3)2·6H2O and 1 g of polyvinylpyrrolidone (PVP) were dissolved in 1 L of deionized water to obtain the electroplating solution. 30 mL of the solution was taken out and placed in a beaker. The solution was deposited for 20 min at a deposition current of 3 mA.

[0063] b. The obtained electrode sheet was placed in a muffle furnace and heated to 350°C at a heating rate of 5°C / min and calcined for 3h to prepare AcCo3O4 / W x O y / ComCo3O4 / NF. .

[0064] ComCo3O4 / NF, AcCo3O4 / ComCo3O4 / NF, W obtained in Example 1 x O y Structural characteristics analysis of / AcCo3O4 / Com Co3O4 / NF:

[0065] Figure 1 ComCo3O4 / NF, AcCo3O4 / ComCo3O4 / NF, and W obtained in Example 1 x O y XRD pattern of / AcCo3O4 / ComCo3O4 / NF.

[0066] from Figure 1 The XRD spectrum analysis shows that ComCo3O4 / NF, AcCo3O4 / ComCo3O4 / NF, W x O yThe three samples of / AcCo3O4 / ComCo3O4 / NF all showed characteristic diffraction peaks consistent with the standard cards of Ni and Co3O4. The characteristic peaks at 2θ of 44.5°, 51.8° and 76.4° correspond to the crystal structure of nickel foam (NF); while the diffraction peaks at 2θ of 31°, 36.8°, 59.6° and 65.2° clearly indicate the presence of cobalt tetroxide (Co3O4) in the sample. It is worth noting that although the sample contains tungsten oxide (W x O y ), but no matching characteristic diffraction peaks appeared in the spectrum. Analysis revealed that this was because the tungsten oxide prepared by electrochemical deposition was in an amorphous state and lacked a long-range ordered crystal structure, thus failing to produce a clear crystal diffraction signal.

[0067] Figure 2 ComCo3O4 / NF, AcCo3O4 / ComCo3O4 / NF, and W obtained in Example 1 x O y Nitrogen isothermal adsorption-desorption curves and specific surface area results of / AcCo3O4 / ComCo3O4 / NF.

[0068] from Figure 2 The nitrogen adsorption curve analysis shows that ComCo3O4 / NF, AcCo3O4 / ComCo3O4 / NF, W x O y Among the three materials, W / AcCo3O4 / ComCo3O4 / NF x O y The / AcCo3O4 / ComCo3O4 / NF sample showed the most significant adsorption performance and the largest specific surface area value. This phenomenon can be attributed to the synergistic effect brought about by structural optimization: the nanosheet-like AcCo3O4 grown on the ComCo3O4 layer significantly expanded the surface active sites of the material due to its unique two-dimensional morphology; at the same time, this nanosheet structure provided abundant nucleation and growth space for the subsequent deposition of tungsten oxide, promoting the W x O y It is evenly dispersed on the surface of AcCo3O4, further increasing the pore structure and specific surface area of ​​the material, which is highly consistent with the experimental data reflected by the nitrogen adsorption curve.

[0069] Figure 3 ComCo3O4 / NF, AcCo3O4 / ComCo3O4 / NF, and W obtained in Example 1 x O ySEM images of / AcCo3O4 / ComCo3O4 / NF, where a is ComCo3O4 / NF, b is AcCo3O4 / ComCo3O4 / NF, and c is W x O y / AcCo3O4 / ComCo3O4 / NF, d is W x O y Cross-sectional SEM image of / AcCo3O4 / ComCo3O4 / NF.

[0070] from Figure 3 It can be clearly observed in a that ComCo3O4 covers the surface of the nickel foam (NF) substrate in the form of a uniform and continuous film layer. This tight coating structure can effectively isolate the direct contact between the electrolyte and the NF, thereby significantly inhibiting the substrate from suffering from anodic corrosion and dissolution. Figure 3 In b, a large number of nanosheet-like AcCo3O4 grow vertically on the surface of ComCo3O4. Its unique two-dimensional morphology not only greatly increases the specific surface area of ​​the material, but also provides abundant active sites for subsequent deposition reactions. It is worth noting that Figure 3 Tungsten oxide (W x O y ) is due to the W generated during the electrochemical deposition process. x O y Due to the low load capacity and extremely small size. Figure 3 The d further confirms the highly effective protective effect of ComCo3O4 on NFs—the ComCo3O4 layer adheres tightly to the NF substrate with virtually no gaps. Furthermore, the orderly growth of AcCo3O4 nanosheets on the ComCo3O4 layer visually demonstrates the successful layered loading of cobalt-tungsten oxides in nickel foam, providing a structural foundation for optimizing material properties.

[0071] Figure 4 W obtained in Example 1 x O y Raman spectrum and X-ray photoelectron spectroscopy of / AcCo3O4 / ComCo3O4 / NF.

[0072] Figure 4 Presented W x O y Raman spectroscopy (Raman) and X-ray photoelectron spectroscopy (XPS) characterization data of / AcCo3O4 / ComCo3O4 / NF materials. Raman spectroscopy analysis shows that at 190.6 cm -1 、470.4cm -1 、511.5cm -1 and 669.0cm -1The characteristic peak at 879.5 cm is highly consistent with the standard spectrum of cobalt trioxide (Co3O4); -1 The vibration peak at 36.9eV corresponds to the stretching vibration of the WO bond, directly reflecting the presence of tungsten oxide. Further XPS characterization revealed that the characteristic peaks observed at binding energies of 36.9eV and 34.7eV are attributed to the spin-orbit splitting peaks of the W4f orbital, respectively. This result provides direct evidence for the valence state and existence form of tungsten in the material. The Raman spectroscopy and XPS characterization results corroborate each other, clearly demonstrating that the nickel foam substrate has successfully achieved the loading of cobalt tungsten oxide, verifying the composition and structural design of the material from the perspectives of molecular vibration and electronic structure.

[0073] Electrochemical performance analysis of the products obtained in the above examples and comparative examples:

[0074] The products obtained in the above examples and comparative examples were used as working electrodes, saturated calomel was used as reference electrodes, and the area was 1×1 cm 2 A platinum sheet was used as the counter electrode, and the electrochemical performance was tested using a three-electrode system in 0.5 mol / L H2SO4 solution.

[0075] Figure 5 These are the electrochemical active area (ECSA) test results after nickel foam is loaded with different cobalt-tungsten oxides.

[0076] Figure 5 It shows that W x O y / AcCo3O4 / ComCo3O4 / NF exhibits the highest electrochemical active area, which means it has a larger electrochemically active surface area and can effectively expose more catalytic active sites. The formation of this excellent performance can be attributed to two mechanisms: First, the nanosheet structure of AcCo3O4 is W x O y The growth of W provides an ideal growth site, significantly increasing the contact area between the material and the electrolyte; secondly, W x O y The synergistic effect of the two further improves the overall performance of the material. In addition, by comparing the performance of materials with different loading sequences, it can be seen that only when W x O y When grown on the surface of cobalt nanosheets AcCo3O4, the catalytic performance can be maximized. x O y Directly loaded on the ComCo3O4 layer, or first deposit W x O y The structure of regrowth of AcCo3O4 cannot fully realize its catalytic potential.

[0077] Figure 6Electrochemical impedance spectroscopy (EIS) test results of nickel foam materials with different cobalt-tungsten oxide loading sequences.

[0078] Figure 6 It shows that W x O y / AcCo3O4 / ComCo3O4 / NF exhibits the lowest charge transfer impedance, which means it has the fastest charge migration rate in the electrochemical reaction. It is worth noting that after the introduction of tungsten oxide on ComCo3O4 / NF, the overall impedance of the system is significantly reduced. This phenomenon also verifies that the layered loading of cobalt tungsten oxide can effectively optimize the electron transfer path of the material. The EIS results directly confirm from a kinetic perspective that by constructing a cobalt tungsten oxide composite structure layer by layer on the surface of nickel foam, not only can the interface resistance be reduced, but the electrochemical activity of the material can also be significantly improved, providing a strong experimental basis for the feasibility of this preparation method.

[0079] Figure 7 The linear voltammetric curves of nickel foam loaded with different cobalt-tungsten oxide materials and their stability test results in acidic medium.

[0080] Figure 7 It shows that ComCo3O4 / NF can operate stably for 12 hours in an acidic environment, showing good basic stability. After further growing cobalt nanosheets (AcCo3O4) on the surface of ComCo3O4 / NF, the oxygen evolution reaction (OER) overpotential is significantly reduced, and the material stability is further improved. In contrast, when tungsten oxide is directly loaded on ComCo3O4 / NF, the performance improvement effect is relatively limited, which is mainly attributed to the low specific surface area characteristics of ComCo3O4 / NF, which makes it difficult to provide sufficient active sites to support the effective growth of tungsten oxide. By depositing tungsten oxide on the surface of cobalt nanosheets, W x O y The / AcCo3O4 / ComCo3O4 / NF composite structure, with its unique layered architecture and synergistic effect, not only significantly reduces the OER overpotential, but also significantly improves the long-term stability of the material in acidic media, fully demonstrating the significant advantages of this layered loading strategy in optimizing electrocatalytic performance.

[0081] The effect of loading cobalt and tungsten oxides on the electrochemical performance of nickel foam was verified. The results are shown in Table 1:

[0082] Table 1

[0083] Catalyst name <![CDATA[Current density (mA / cm 2 )]]> Overpotential (mV) <![CDATA[ComCo3O4 / NF]]> 10 386 <![CDATA[W x O y / ComCo3O4 / NF]]> 10 338 <![CDATA[AcCo3O4 / ComCo3O4 / NF]]> 10 304 <![CDATA[AcCo3O4 / W x O y / ComCo3O4 / NF]]> 10 322 <![CDATA[W x O y / AcCo3O4 / ComCo3O4 / NF]]> 10 265

[0084] Table 1 systematically compares the effects of different loading sequences of cobalt tungsten oxides on nickel foam substrates on material properties. Experimental results show that the loading sequence has a significant impact on the electrochemical properties of the material: directly depositing tungsten oxide on ComCo3O4 / NF, due to the limited specific surface area of ​​ComCo3O4 / NF, it is difficult to provide sufficient active sites, resulting in poor performance improvement; while first growing cobalt nanosheets (AcCo3O4) on ComCo3O4 / NF to form a three-dimensional porous structure and then depositing tungsten oxide (W x O y ), which can give full play to the catalytic performance of the material. x O y / AcCo3O4 / ComCo3O4 / NF composite catalyst, which has a 2 At a current density of 1.5 GHz, the catalyst exhibited an ultra-low overpotential of only 265 mV, significantly outperforming most similar non-precious metal materials. Constant current testing confirmed that the catalyst operated continuously in strong acid for over 12 hours.

[0085] The various embodiments in this specification are described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The same or similar parts between the various embodiments can be referenced to each other.

[0086] The above description of the disclosed embodiments is intended to enable one skilled in the art to implement or use the present invention. Various modifications to these embodiments will be readily apparent to one skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention is not limited to the embodiments shown herein but is intended to conform to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A method for preparing a nickel foam layered loaded cobalt-tungsten oxide catalyst for efficient water splitting, characterized in that: The steps include: S1, sequentially subjecting nickel foam to electrochemical deposition treatment using a cobalt source and an acid reagent as an electroplating solution, oxidation using a potassium hydroxide solution as an electroplating solution, and calcination to obtain ComCo3O4 / NF; S2, sequentially subjecting the ComCo3O4 / NF to electrochemical deposition treatment using a cobalt source and polyvinyl pyrrolidone as an electroplating solution, and calcining to obtain AcCo3O4 / ComCo3O4 / NF; S3, the AcCo3O4 / ComCo3O4 / NF is subjected to electrochemical deposition treatment using a tungsten source as an electroplating solution and calcined in sequence to obtain the foamed nickel layered loaded cobalt tungsten oxide catalyst for efficient water decomposition, denoted as W x O y / AcCo3O4 / ComCo3O4 / NF.

2. The preparation method according to claim 1, characterized in that In step S1: the cobalt source includes cobalt nitrate and / or cobalt sulfate; the electroplating solution is added in the form of an aqueous solution; in the electroplating solution, the concentration of the cobalt source is 0.1-0.2 mol / L, and the concentration of the acid reagent is 0.5-0.7 mol / L; the acid reagent includes boric acid and / or oxalic acid.

3. The preparation method according to claim 1, characterized in that In step S1, the deposition current of the electrochemical deposition treatment is 15 to 20 mA, and the deposition time is 60 to 90 min; the concentration of the potassium hydroxide solution is 0.5 to 1 mol / L, and the oxidation current is 3 to 6 mA; the calcination heating rate is 5°C / min, the temperature is 500°C, and the holding time is 3 to 5 h.

4. The preparation method according to claim 1, characterized in that In step S2: the cobalt source includes cobalt nitrate and / or cobalt sulfate; the electroplating solution is added in the form of an aqueous solution; in the electroplating solution, the concentration of the cobalt source is 0.05-0.1 mol / L, and the concentration of polyvinyl pyrrolidone is 1-2 g / L.

5. The preparation method according to claim 1, characterized in that In step S2, the deposition current of the electrochemical deposition treatment is 3-6 mA, and the deposition time is 30-45 min; the heating rate of the calcination is 5° C. / min, the temperature is 350° C., and the holding time is 3-5 h.

6. The preparation method according to claim 1, characterized in that In step S3: the tungsten source includes sodium tungstate and / or potassium tungstate; the electroplating solution is added in the form of an aqueous solution; and the concentration of sodium tungstate in the electroplating solution is 0.1-0.5 mol / L.

7. The preparation method according to claim 1, characterized in that In step S3: the deposition current of the electrochemical deposition treatment is 10-15 mA, and the deposition time is 20-30 min; the heating rate of the calcination is 5° C. / min, the temperature is 350° C., and the holding time is 3-5 h.

8. A nickel foam layered loaded cobalt-tungsten oxide catalyst for efficient water decomposition prepared by the preparation method according to any one of claims 1 to 7.

9. Use of the nickel foam layered loaded cobalt tungsten oxide catalyst for efficient water decomposition according to claim 8 in hydrogen production by electrolysis of water.

10. A method for improving the effect and stability of hydrogen production by electrolysis of water, characterized in that: The steps include: The nickel foam layered loaded with cobalt tungsten oxide catalyst for efficient water decomposition according to claim 8 is used as a working electrode, a platinum sheet is used as a counter electrode, a saturated calomel electrode is used as a reference electrode, and a 0.5 mol / L H2SO4 solution is used as an electrolyte to carry out water electrolysis reaction in a three-electrode system.

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