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

Abstract

The application discloses a preparation and application of a foam nickel layered cobalt-tungsten oxide catalyst for efficient water decomposition and belongs to the technical field of electrochemical catalysis. Foam nickel (NF) is selected as a substrate, and two kinds of cobalt oxides with different morphologies are grown in sequence through electrochemical deposition, wherein ComCo3O4 is a first layer, can tightly wrap the NF, and makes the NF not subject to anode corrosion and dissolution in a harsh acidic medium, and AcCo3O4 is a second layer, the nanosheet-shaped Co3O4 has good OER activity, in addition, a larger specific surface area provides more growth sites for tungsten oxide, and finally, tungsten oxide is electro-deposited on the AcCo3O4, and the W x O y / AcCo3O4 / ComCo3O4 / NF prepared through the above method has a lower overpotential and good stability.

Description

Technical Field

[0001] This invention belongs to the field of electrochemical catalysis technology, and more specifically relates to the preparation and application of a foam nickel layered supported cobalt tungsten oxide catalyst for efficient water splitting. Background Technology

[0002] Hydrogen has a high calorific value, more than three times that of petroleum, making it an ideal alternative to fossil fuels. Furthermore, hydrogen combustion produces no harmful or greenhouse gases. Electrocatalytic water electrolysis is one of the most promising strategies for meeting future human energy needs. Among different oxygen evolution reaction (OER) hydrogen production technologies, proton exchange membrane (PEM) water electrolysis demonstrates advantages in productivity, energy stability, and cost compared to other hydrogen production technologies. However, achieving efficient and sustainable large-scale hydrogen production via PEM still faces significant challenges. Specifically, there is a lack of stable and inexpensive OER catalysts that can operate at high current densities. While noble metal-based catalysts, such as Ru-based and Ir-based catalysts, exhibit good stability and activity, they still suffer from metal dissolution in the inherently acidic medium of the lattice OER mechanism. Therefore, there is an urgent need to develop effective and stable noble metal-free anodic OER catalysts for PEM.

[0003] Various 3d transition metal oxides and their derivatives have attracted widespread attention as OER candidates due to their high abundance and low cost. Among them, cobalt-based oxides exhibit good OER activity in acidic media and are considered one of the most promising OER candidates. Theoretical calculations suggest that 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 potentials. This expected activity is challenged by the limited stability of cobalt oxides in acid. Therefore, the preparation of highly active and stable cobalt-based anodic oxygen evolution catalysts remains a significant challenge. Summary of the Invention

[0004] The purpose of this invention is to provide a method for preparing and applying a foamed nickel-layered supported cobalt-tungsten oxide catalyst for efficient water splitting, in order to solve the problems existing in the prior art and achieve the preparation of a highly active and stable cobalt-based anodic oxygen evolution catalyst.

[0005] To achieve the above objectives, the present invention provides the following solution:

[0006] One of the technical solutions of this invention is to provide a method for preparing a foamed nickel-layered supported cobalt-tungsten oxide catalyst for high-efficiency water splitting, comprising the following steps:

[0007] S1. The nickel foam was subjected to electrochemical deposition treatment with cobalt source and boric acid as electroplating solution, oxidation with potassium hydroxide solution as electroplating solution, and calcination to obtain ComCo3O4 / NF.

[0008] S2. The ComCo3O4 / NF is subjected to electrochemical deposition treatment with cobalt source and polyvinylpyrrolidone as electroplating solution in sequence, followed by calcination to obtain AcCo3O4 / ComCo3O4 / NF;

[0009] S3. The AcCo3O4 / ComCo3O4 / NF is sequentially subjected to electrochemical deposition treatment using a tungsten source as the electroplating solution, followed by calcination, to obtain the foamed nickel layered supported cobalt tungsten oxide catalyst for efficient water splitting, denoted as W. x O y / AcCo3O4 / ComCo3O4 / NF.

[0010] The "W" involved in this invention x O y " indicates tungsten oxide, where x and y are the atomic ratio of tungsten to 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 electrochemical deposition in step S1 can be oxidized into cobalt hydroxide.

[0013] Preferably, in step S1, the deposition current of the electrochemical deposition treatment is 15-20 mA, the deposition time is 60-90 min; the concentration of the potassium hydroxide solution is 0.5-1 mol / L, the oxidation current is 3-6 mA; the calcination heating rate is 5 °C / min, the temperature is 500 °C, and the holding time is 3-5 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 polyvinylpyrrolidone is 1-2 g / L.

[0015] In step S2, polyvinylpyrrolidone acts as a surfactant, which allows cobalt ions to be deposited from the solution as nanosheet-like cobalt compounds.

[0016] Preferably, in step S2, the deposition current of the electrochemical deposition treatment is 3-6 mA, 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, 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 provides a foamed nickel layered supported cobalt tungsten oxide catalyst for efficient water splitting prepared by the above preparation method.

[0020] The third technical solution of the present invention provides the application of the above-mentioned foamed nickel layered supported cobalt tungsten oxide catalyst for efficient water splitting in the electrolysis of water to produce hydrogen.

[0021] Fourth technical solution of the present invention: A method for improving the efficiency and stability of hydrogen production through water electrolysis, comprising the following steps:

[0022] The electrolysis of water was carried out in a three-electrode system using the foamed nickel layered supported cobalt tungsten oxide catalyst for efficient water splitting as the working electrode, a platinum sheet as the counter electrode, a saturated calomel electrode as the reference electrode, and a 0.5 mol / L H2SO4 solution as the electrolyte.

[0023] The technical principle of this invention is as follows:

[0024] This invention uses nickel foam (NF) as a substrate and electrochemically deposits two different cobalt oxide morphologies sequentially. The first layer, ComCo3O4, tightly encapsulates the NF, preventing anodic corrosion and dissolution under harsh acidic conditions. The second layer, AcCo3O4, consists of nanosheet-like Co3O4 with excellent OER activity. Furthermore, its large specific surface area provides more growth sites for tungsten oxide. Finally, tungsten oxide is electrodeposited onto the AcCo3O4. The resulting W... x O y / AcCo3O4 / ComCo3O4 / NF exhibits low overpotential and good stability.

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

[0026] 1. The catalyst preparation method described in this invention employs a simple process combining electrochemical deposition and calcination, requiring no complex equipment or harsh reaction conditions. First, the target material is uniformly deposited onto the substrate surface using electrochemical deposition under mild reaction conditions, relying solely on electrical energy. Subsequently, it is placed in a conventional muffle furnace for calcination. The entire process is simple and easy to understand, with readily available raw materials, requiring no lengthy operation by specialized technicians, significantly lowering the preparation threshold and demonstrating high feasibility and practicality.

[0027] 2. The catalyst of this invention innovatively employs a multi-layered composite structure design, cleverly integrating cobalt oxides of different morphologies to construct a synergistic microscopic system. The dense cobalt tetroxide protects the nickel foam substrate from anodic corrosion and damage to the overall material structure. The three-dimensional, interwoven arrangement of nanosheet-like cobalt tetroxide creates abundant space, providing ideal growth sites and attachment spaces for the subsequent growth of tungsten oxides. Through this design, the quality and quantity of active sites in the material are optimized, ensuring the catalytic efficiency of individual active sites while expanding the reaction area by increasing the number of sites, ultimately achieving a comprehensive improvement in performance.

[0028] 3. The catalyst of this invention uses transition elements that are abundant and inexpensive in the Earth's crust as raw materials, and the catalyst operates at 10 mA / cm². 2 At a current density of only 266mV, the catalyst exhibits an ultra-low overpotential of just 266mV, significantly outperforming most similar non-precious metal materials. Constant current testing verified that the catalyst maintained its structural integrity and catalytic activity even after continuous operation in strong acid for over 12 hours, demonstrating excellent corrosion resistance and anti-degradation performance. Through lower raw material costs and optimized energy consumption, the cost of hydrogen production via water electrolysis is effectively reduced. Attached Figure Description

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

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

[0031] Figure 3The ComCo3O4 / NF, AcCo3O4 / ComCo3O4 / NF, and W obtained in Example 1 x O y SEM images of / AcCo3O4 / ComCo3O4 / NF, where a represents ComCo3O4 / NF, b represents AcCo3O4 / ComCo3O4 / NF, and c represents 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 and X-ray photoelectron spectra of / AcCo3O4 / ComCo3O4 / NF;

[0033] Figure 5 The electrochemically active surface area (ECSA) test results are shown for nickel foam loaded with different cobalt and tungsten oxides.

[0034] Figure 6 Electrochemical impedance spectroscopy (EIS) results for nickel foam materials with different cobalt-tungsten oxide loading sequences;

[0035] Figure 7 Linear current-voltage curves of nickel foam loaded with different cobalt-tungsten oxide materials and their stability test results in acidic media. Detailed Implementation

[0036] Various exemplary embodiments of the present invention will now be described in detail. This detailed description should not be considered as a limitation of 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 terminology used in this invention is merely for describing particular embodiments and is not intended to limit the invention. Furthermore, with respect to numerical ranges in this invention, it should be understood that each intermediate value between the upper and lower limits of the range is also specifically disclosed. Any stated value or intermediate value within a stated range, as well as each smaller range between any other stated value or intermediate value within said range, is also included in this invention. The upper and lower limits of these smaller ranges may be independently included or excluded from the range.

[0038] Unless otherwise stated, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art. While only preferred methods and materials have been described herein, any methods and materials similar or equivalent to those described herein may be used in the implementation or testing of this invention. All references to this specification are incorporated by way of citation to disclose and describe methods and / or materials associated with those references. In the event of any conflict with any incorporated reference, the content of this specification shall prevail.

[0039] Various modifications and variations can be made to the specific embodiments described in this specification without departing from the scope or spirit of the invention, as will be apparent to those skilled in the art. Other embodiments derived from this specification will also be readily apparent to those skilled in the art. This specification and embodiments are merely exemplary.

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

[0041] It should be noted that any aspects not described in detail in this invention are conventional practices in the field and are not the focus of this invention.

[0042] Unless otherwise specified, all raw materials used in the following embodiments and comparative examples of this invention are commercially available products, and the source of these commercially available products does not affect the technical effect of this invention.

[0043] The foamed nickel of this 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 layered nickel foam supported 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 of deionized water to obtain an electroplating solution. Take 30mL of the solution into a beaker, and then pour it into a container with an area of ​​1×2cm². 2 The working electrode is a nickel foam with an area of ​​1×2 cm². 2 The carbon sheet electrode was deposited for 60 minutes at a deposition current of 15mA, and then allowed to air dry naturally.

[0048] b. Use this electrode sheet as the working electrode; its area is 1×2cm. 2 The carbon sheet was used as the counter electrode. It was completely oxidized in a 1 mol / L potassium hydroxide solution. The oxidation current was 3 mA and the oxidation time was 60 min.

[0049] c. The obtained electrode sheet was placed in a muffle furnace and heated to 500℃ for 3 hours at a heating rate of 5℃ / min 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 of deionized water to obtain an electroplating solution. Take 30mL of this solution and place it in a beaker. Use ComCo3O4 / NF as the working electrode with an area of ​​1×2cm². 2 The carbon sheet was used as the counter electrode, and it was deposited in the electroplating 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℃ for 3h at a heating rate of 5℃ / min to prepare AcCo3O4 / ComCo3O4 / NF.

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

[0054] a. The electroplating solution is a 0.1 mol / L sodium tungstate solution. Take 30 mL into a beaker and use AcCo3O4 / ComCo3O4 / NF as the working electrode with an area of ​​1×2 cm². 2 The carbon sheet was used as the counter electrode and deposited in the electroplating 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℃ at a heating rate of 5℃ / min for 3 hours to prepare W. x O y / AcCo3O4 / ComCo3O4 / NF.

[0056] Comparative Example 1 (Changing the order of cobalt-tungsten oxide deposition)

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

[0058] a. Using the ComCo3O4 / NF prepared in Example 1 as the working electrode and the carbon sheet as the counter electrode, the electroplating solution was a 0.1 mol / L sodium tungstate solution. 30 mL of the solution was taken out and placed in a beaker, and 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℃ at a heating rate of 5℃ / min for 3 hours 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 according to Comparative Example 1 x O y / ComCo3O4 / NF was used as the working electrode and a carbon sheet as the counter electrode. 28g Co(NO3)2·6H2O and 1g polyvinylpyrrolidone (PVP) were dissolved in 1L of deionized water to obtain an electroplating solution. 30mL of the solution was taken out and placed in a beaker. The solution was deposited for 20min with a deposition current of 3mA.

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

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

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

[0066] from Figure 1 XRD pattern analysis revealed that ComCo3O4 / NF, AcCo3O4 / ComCo3O4 / NF, and W x O yAll three samples (AcCo3O4, ComCo3O4, and NF) exhibited characteristic diffraction peaks consistent with the standard cards for 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 samples. It is noteworthy that although the samples contain electrochemically deposited tungsten oxide (W... x O y However, 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 obvious crystal diffraction signals.

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

[0068] from Figure 2 Analysis of nitrogen adsorption curves showed that ComCo3O4 / NF, AcCo3O4 / ComCo3O4 / NF, and W x O y Of the three materials / AcCo3O4 / ComCo3O4 / NF, W x O y The / AcCo3O4 / ComCo3O4 / NF sample exhibited the most significant adsorption performance, corresponding to the largest specific surface area. This phenomenon can be attributed to the synergistic effect of structural optimization: the nanosheet-like AcCo3O4 grown on the ComCo3O4 layer significantly expanded the active sites on the material surface due to its unique two-dimensional morphology; simultaneously, this nanosheet structure provided abundant nucleation and growth space for subsequent tungsten oxide deposition, promoting W x O y Uniform dispersion on the AcCo3O4 surface further increases the pore structure and specific surface area of ​​the material, which is in high agreement with the experimental data reflected by the nitrogen adsorption curve.

[0069] Figure 3 The ComCo3O4 / NF, AcCo3O4 / ComCo3O4 / NF, and W obtained in Example 1 x O ySEM images of / AcCo3O4 / ComCo3O4 / NF, where a represents ComCo3O4 / NF, b represents AcCo3O4 / ComCo3O4 / NF, and c represents W. x O y / AcCo3O4 / ComCo3O4 / NF, d is W x O y SEM image of the cross section of / AcCo3O4 / ComCo3O4 / NF.

[0070] from Figure 3 As can be clearly observed in image a, ComCo3O4 forms a uniform and continuous film covering the surface of the nickel foam (NF) substrate. This tight coating structure effectively isolates the electrolyte from direct contact with NF, thereby significantly inhibiting anodic corrosion dissolution of the substrate. Figure 3 In step b, numerous nanosheet-like AcCo3O4 particles grow vertically on the surface of ComCo3O4. Their unique two-dimensional morphology not only significantly 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) was not directly observed in c. x O y The presence of W is due to the formation of W during the electrochemical deposition process. x O y Due to its low load capacity and extremely small size. Figure 3 The results further confirm the highly efficient protective effect of ComCo3O4 on NF—the ComCo3O4 layer adheres tightly to the NF substrate with almost no gaps. Furthermore, the orderly growth of AcCo3O4 nanosheets on the ComCo3O4 layer directly verifies that nickel foam successfully achieved layered loading of cobalt-tungsten oxide, providing a structural basis for optimizing material properties.

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

[0072] Figure 4 W was presented x O y Raman and X-ray photoelectron spectroscopy (XPS) characterization data of the / AcCo3O4 / ComCo3O4 / NF material. Raman spectroscopy analysis shows that at 190.6 cm⁻¹... -1 470.4cm -1 511.5cm -1 and 669.0cm -1The characteristic peak appearing at 879.5 cm⁻¹ is highly consistent with the standard spectrum of cobalt tetroxide (Co₃O₄); while the peak at 879.5 cm⁻¹... -1 The vibrational peaks at these locations correspond to the stretching vibrations of the WO bond, directly reflecting the presence of tungsten oxide. Further XPS characterization revealed that the characteristic peaks observed at binding energies of 36.9 eV and 34.7 eV are attributed to spin-orbit splitting peaks of the W4f orbital, providing direct evidence for the valence state and 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 material's composition and structural design at the molecular vibrational and electronic structure levels.

[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, and saturated calomel was used as a reference electrode with an area of ​​1×1 cm². 2 A platinum sheet was used as the counter electrode, and its electrochemical performance was tested using a three-electrode system in a 0.5 mol / L H2SO4 solution.

[0075] Figure 5 The electrochemical active area (ECSA) test results are shown for nickel foam loaded with different cobalt and tungsten oxides.

[0076] Figure 5 This indicates that W x O y / AcCo3O4 / ComCo3O4 / NF exhibits the highest electrochemically active area, meaning it possesses a larger electrochemically activated surface region, effectively exposing more catalytically active sites. This superior performance can be attributed to a dual mechanism: firstly, the nanosheet structure of AcCo3O4 provides W... x O y The growth site provides ideal growth sites, significantly increasing the contact area between the material and the electrolyte; secondly, W x O y Both possess excellent intrinsic electrocatalytic activity, and their synergistic effect further enhances the overall performance of the material. Furthermore, by comparing the material performance under different loading orders, it can be seen that only when W... x O y The catalytic performance can only be maximized when grown on the surface of cobalt nanosheets AcCo3O4, while W x O y Directly loaded onto the ComCo3O4 layer, or first deposited W x O y The regenerated AcCo3O4 structure could not fully realize its catalytic potential.

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

[0078] Figure 6 This indicates that W x O y The / AcCo3O4 / ComCo3O4 / NF structure exhibits the lowest charge transfer impedance, indicating the fastest charge migration rate in electrochemical reactions. Notably, the overall impedance of the system significantly decreases after introducing tungsten oxide onto ComCo3O4 / NF, validating that layered loading of cobalt-tungsten oxide effectively optimizes the electron transport path. EIS results directly confirm from a kinetic perspective that constructing a cobalt-tungsten oxide composite structure layer-by-layer on the nickel foam surface not only reduces interfacial resistance but also significantly enhances the electrochemical activity of the material, providing strong experimental evidence for the feasibility of this preparation method.

[0079] Figure 7 Linear current-voltage curves of nickel foam loaded with different cobalt-tungsten oxide materials and their stability test results in acidic media.

[0080] Figure 7 The results showed that ComCo3O4 / NF operated stably for 12 hours under acidic conditions, exhibiting good basic stability. Further growth of cobalt nanosheets (AcCo3O4) on the surface of ComCo3O4 / NF significantly reduced the oxygen evolution reaction (OER) overpotential and further improved material stability. In contrast, directly loading tungsten oxide onto ComCo3O4 / NF resulted in relatively limited performance improvement, mainly due to the low specific surface area of ​​ComCo3O4 / NF, which makes it difficult to provide sufficient active sites to support the effective growth of tungsten oxide. However, the W... x O y The / AcCo3O4 / ComCo3O4 / NF composite structure, with its unique hierarchical 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 hierarchical loading strategy in optimizing electrocatalytic performance.

[0081] The effect of loading cobalt-tungsten oxide onto nickel foam sequentially on its electrochemical performance was verified, and 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 compares the effects of different loading sequences of cobalt and tungsten oxides on the material properties on nickel foam substrates. Experimental results show that the loading sequence has a significant impact on the electrochemical performance of the material: direct deposition of tungsten oxides on ComCo3O4 / NF results in poor performance improvement due to the limited specific surface area of ​​ComCo3O4 / NF, which makes it difficult to provide sufficient active sites; while first growing cobalt nanosheets (AcCo3O4) on ComCo3O4 / NF to form a three-dimensional porous structure, followed by deposition of tungsten oxides (W... x O y This strategy allows for the full utilization of the material's catalytic performance. W prepared under this strategy... x O y / AcCo3O4 / ComCo3O4 / NF composite catalyst, which has a performance of 10 mA / cm 2 At a current density of only 265mV, the catalyst exhibits an ultra-low overpotential of just 265mV, significantly outperforming most similar non-precious metal materials. Constant current testing verified 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, with each embodiment focusing on the differences from other embodiments. The same or similar parts between the various embodiments can be referred to each other.

[0086] The above description of the disclosed embodiments enables those skilled in the art to make or use the invention. Various modifications to these embodiments will be readily apparent to those 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 invention. Therefore, the invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A method for preparing a foamed nickel-layered supported cobalt-tungsten oxide catalyst for efficient water splitting, characterized in that, Includes the following steps: S1. The foamed nickel was subjected to electrochemical deposition treatment with cobalt source and acid reagent as electroplating solution, oxidation with potassium hydroxide solution as electroplating solution, and calcination to obtain ComCo3O4 / NF. S2. The ComCo3O4 / NF is subjected to electrochemical deposition treatment with cobalt source and polyvinylpyrrolidone as electroplating solution in sequence, followed by calcination to obtain AcCo3O4 / ComCo3O4 / NF; S3. The AcCo3O4 / ComCo3O4 / NF is sequentially subjected to electrochemical deposition treatment using a tungsten source as the electroplating solution, followed by calcination, to obtain the foamed nickel layered supported cobalt tungsten oxide catalyst for efficient water splitting, denoted as W. x O y / AcCo3O4 / ComCo3O4 / NF; ComCo3O4 represents dense cobalt tetroxide; AcCo3O4 represents nanosheet-like cobalt tetroxide; W x O y This indicates tungsten oxide, where x and y are the atomic ratios of tungsten and oxygen, including WO3 or W2O5.

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 15~20mA, and the deposition time is 60~90min; the concentration of the potassium hydroxide solution is 0.5~1mol / L, and the oxidation current is 3~6mA; the heating rate of the calcination is 5℃ / min, the temperature is 500℃, and the holding time is 3~5h.

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 0.05~0.1mol / L, and the concentration of polyvinylpyrrolidone is 1~2g / L.

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

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; in the electroplating solution, the concentration of sodium tungstate 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 10~15mA, the deposition time is 20~30min; the heating rate of the calcination is 5℃ / min, the temperature is 350℃, and the holding time is 3~5h.

8. The foamed nickel layered supported cobalt tungsten oxide catalyst for efficient water splitting prepared by the preparation method according to any one of claims 1 to 7.

9. The application of the foamed nickel layered supported cobalt tungsten oxide catalyst for efficient water splitting as described in claim 8 in water electrolysis for hydrogen production.

10. A method for improving the efficiency and stability of hydrogen production through water electrolysis, characterized in that, Includes the following steps: Using the foamed nickel layered supported cobalt tungsten oxide catalyst for efficient water splitting as described in claim 8 as the working electrode, a platinum sheet as the counter electrode, a saturated calomel electrode as the reference electrode, and a 0.5 mol / L H2SO4 solution as the electrolyte, the water electrolysis reaction is carried out in a three-electrode system.

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