Special-shaped nano-catalyst as well as preparation method and application thereof

Abstract

The invention provides a special-shaped nano-catalyst as well as a preparation method and application thereof. The special-shaped nano-catalyst comprises a special-shaped nano-catalyst structure, and the morphology induction layer is formed on a part of the surface of the special-shaped nano catalyst structure. According to the special-shaped nano-catalyst and the preparation method and application thereof, the special-shaped nano-catalyst of different structures is obtained, the specific surface area of the special-shaped nano-catalyst is increased, the catalytic performance is improved, and when a membrane electrode is formed, the porosity can be increased, the bed pressure drop can be reduced, water diffusion is facilitated, and the catalytic efficiency is improved.

Description

[0001] This application claims partial priority to Chinese Patent Application No. 2024105102683, filed on April 26, 2024, entitled “A Shaped Nanocatalyst and Its Preparation Method and Application”, the contents of which are incorporated herein by reference. Technical Field

[0002] This invention relates to the field of water electrolysis for hydrogen production technology, specifically to a heteromorphic nanocatalyst, its preparation method, and its application. Background Technology

[0003] With the increasing consumption of fossil fuels and the resulting environmental problems, people are paying more and more attention to the development and utilization of sustainable and renewable clean energy. Compared with wind power, hydropower, and solar energy, hydrogen energy is considered a very promising clean energy source because it is not limited by geographical or application environments. Currently, there are many ways to produce hydrogen, including water electrolysis, coal gasification, and catalytic conversion of heavy oil and natural gas into hydrogen. Among these, the most practical and cleanest method is water electrolysis.

[0004] However, the catalysts currently in use have low catalytic efficiency and high catalytic costs, which limit the development of hydrogen production technology. Summary of the Invention

[0005] This invention proposes a heteromorphic nanocatalyst, its preparation method, and its application. It can increase the specific surface area of ​​the catalyst, enhance catalytic performance, increase porosity, reduce bed pressure drop, facilitate water diffusion, and accelerate catalytic efficiency when forming a membrane electrode.

[0006] To solve the above-mentioned technical problems, the present invention is achieved through the following technical solution.

[0007] This invention provides a heteromorphic nanocatalyst, comprising:

[0008] heterogeneous nanocatalyst structures; and

[0009] A morphology-inducing layer is formed on a portion of the surface of the heteromorphic nanocatalyst structure.

[0010] In one embodiment of the present invention, the shape of the heteromorphic nanocatalyst structure is one or a combination of several of the following: polyhedral, needle-shaped, pointed prism-shaped, spherical, chain-like, or fused spherical.

[0011] In one embodiment of the present invention, the morphology-inducing layer is at least one layer. When the morphology-inducing layer is multilayered, the multiple morphology-inducing layers are sequentially stacked on the irregular nanocatalyst structure.

[0012] In one embodiment of the present invention, the material of the heteromorphic nanocatalyst structure is at least one of a metal, an alloy, or a metal oxide, and the material of the morphology-inducing layer is at least one of a metal, an alloy, or a metal oxide.

[0013] In one embodiment of the present invention, the heteromorphic nanocatalyst comprises at least two of transition metals, lanthanide rare earth elements, and platinum group noble metal elements, wherein the transition metal elements comprise at least one of Mn, Cr, Zr, Fe, Co, Ni, Cu, Zn, Mo, or W, and the platinum group noble metal elements comprise at least one of Ru, Rh, Pd, Ag, Os, Ir, Pt, or Au.

[0014] The present invention also provides a method for preparing the above-described heteromorphic nanocatalyst, comprising at least:

[0015] Preparation of metal precursor solutions;

[0016] A morphology inducer is added to the metal precursor solution;

[0017] Under alkaline conditions, the mixture is stirred at a preset temperature for a preset time to obtain an intermediate; and

[0018] The intermediate was cleaned and dried to obtain a heteromorphic nanocatalyst.

[0019] In one embodiment of the present invention, the morphology inducing agent includes isophthalic acid ester, phthalate, 1,4-diazabicyclo[2.2.2]octane, triethylenediamine, 1,4-dimethylpiperazine, hexamethylenetetramine, pyromellitic acid, pyromellitic tricarboxylic acid, 1,4-bis(1H-pyrazol-4-yl)benzene, 1,4,7,10-tetraazacyclododecane-1,4,7,10-tetracarboxylic acid, 2,4,6-tris(4-pyridyl)-1,3,5-triazine, and tris(isobutylaminoethyl) At least one of the following: amine, bis(3,5-dicarboxyphenyl)azo, biphenyl phthalic acid, 2,5-dihydroxyterephthalic acid, 2,6-naphthalenedicarboxylic acid, 1,4-phenylene diacetic acid, 1,1,2,2-tetra(4-carboxyphenyl)ethylene, 1,3,5-tris(4-carboxyphenyl)benzene, 2-(diphenylphosphino)terephthalic acid, 2-amino-4-hydroxy-6-methylpyrimidine, 2-methylimidazole, 2-aminoterephthalic acid, terephthalic acid, fumaric acid, and trioctyl trimellitate.

[0020] In one embodiment of the present invention, the preparation method further includes repeating the formation step of the shaped nanocatalyst to obtain the shaped nanocatalyst having multiple morphology-inducing layers.

[0021] The present invention also provides an electrode for a hydrogen electrolyzer, comprising: a substrate and the electrode catalyst described above.

[0022] The present invention also provides a hydrogen production electrolyzer, including the electrodes described above.

[0023] In summary, this invention proposes a heteromorphic nanocatalyst, its preparation method, and its application. The catalyst has a large specific surface area, increasing catalytic performance. Simultaneously, it increases porosity and reduces bed pressure drop during membrane electrode formation, facilitating water diffusion and accelerating catalytic efficiency. Furthermore, the heteromorphic catalyst improves processing performance during membrane electrode formation. By forming heteromorphic nanocatalysts of different shapes and sizes, membrane electrodes with varying catalytic capabilities can be formed, meeting the needs of different environments or requirements. The reactants and reaction conditions can be controlled to obtain heteromorphic nanocatalysts with predetermined morphologies. Attached Figure Description

[0024] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0025] Figure 1 The image shown is a scanning electron microscope image of an irregularly shaped nanocatalyst in one embodiment.

[0026] Figure 2A-2C The image shown is a scanning electron microscope image of the irregularly shaped nanocatalyst in the examples.

[0027] Figure 3 The image shown is a scanning electron microscope (SEM) image and an X-ray energy dispersive spectroscopy (EDS) image of an irregularly shaped nanocatalyst as an example.

[0028] Figure 4 The image shown is a scanning electron microscope image and an X-ray energy dispersive spectroscopy (EDS) image of the irregularly shaped nanocatalyst, as shown in another embodiment.

[0029] Figure 5 This is a structural diagram of the electrodes of an electrolytic cell in one embodiment of this application.

[0030] Figure 6 This is a schematic diagram of an electrode observed with a magnification of 10,000x using a scanning electron microscope in one embodiment of this application.

[0031] Figure 7 This is a schematic diagram of the electrodes of a hydrogen electrolyzer observed with a scanning electron microscope at a magnification of 50x in one embodiment of this application.

[0032] Figure 8 This is a comparison diagram showing the performance tests of the electrodes in a hydrogen electrolyzer in one embodiment and a comparative example of this application.

[0033] Figure 9-11 This is a schematic diagram of the electrolytic cell in an embodiment of this application.

[0034] Figure 12-15 This is a schematic diagram of the electrodes in an embodiment of this application.

[0035] Figure 16-17 This is a schematic diagram of the surface treatment layer in one embodiment of this application.

[0036] Figure 18 This is a schematic diagram of an electrolytic cell in one embodiment of this application. Detailed Implementation

[0037] The following specific examples illustrate the implementation of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and various details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of the present invention.

[0038] It should be understood that the present invention can be implemented in various forms and should not be construed as being limited to the embodiments set forth herein. Rather, providing these embodiments will make the disclosure thorough and complete, and will fully convey the scope of the invention to those skilled in the art. Unless otherwise specified, “%” and “parts” as shown in the following embodiments refer to “% by mass” and “parts by mass”, respectively.

[0039] The technical solution of the present invention will be further described in detail below with reference to several embodiments and accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0040] Please see Figures 1 to 6 As shown, in one embodiment of the present invention, a heteromorphic nanocatalyst is provided for use in a water electrolysis hydrogen production device. The heteromorphic nanocatalyst includes a heteromorphic nanocatalyst structure 10 and a morphology-inducing layer 11, the morphology-inducing layer 11 being formed on a portion of the surface of the heteromorphic nanocatalyst structure 10. In one embodiment of the present invention, the morphology-inducing layer 11 is, for example, at least one layer; when the morphology-inducing layer 11 is multilayered, the multiple morphology-inducing layers 11 are sequentially stacked on the heteromorphic nanocatalyst structure 10. In one embodiment of the present invention, the specific surface area of ​​the heteromorphic nanocatalyst can be, for example, greater than or equal to 100 m². 2 / g, for example, 100~1000m 2 / g. By forming heterogeneous nanocatalysts, the catalyst has a larger specific surface area, which increases the catalytic performance. At the same time, it can increase the porosity and reduce the bed pressure drop during the formation of the membrane electrode, which is conducive to water diffusion and accelerates the catalytic efficiency. Moreover, the heterogeneous catalyst improves the processing performance during the formation of the membrane electrode.

[0041] Please see Figures 1 to 6 As shown, in one embodiment of the present invention, the shape of the heteromorphic nanocatalyst is, for example, one or a combination of several of the following: polyhedral, needle-shaped, pointed prism-shaped, spherical, chain-like, or fused spherical, and can be specifically controlled according to the fabrication process. The size of the heteromorphic nanocatalyst varies depending on its shape, and is determined specifically based on the morphology of the formed heteromorphic nanocatalyst. By forming heteromorphic nanocatalysts of different shapes and sizes, membrane electrodes with different catalytic capabilities can be formed during membrane electrode formation, meeting the needs of use under different environments or requirements.

[0042] In another embodiment of the present invention, the heteromorphic nanocatalyst comprises at least two of transition metals, lanthanide rare earth elements, and platinum group noble metal elements. The transition metals include, for example, at least one of Mn, Cr, Zr, Fe, Co, Ni, Cu, Zn, Mo, or W. The platinum group noble metal elements include at least one of Ru, Rh, Pd, Ag, Os, Ir, Pt, or Au. In one embodiment of the present invention, the electrocatalyst comprises, for example, the following components by mass percentage: 40%–60% transition metal, 20%–50% lanthanide rare earth elements and / or platinum group noble metal elements, and 5%–20% oxygen.

[0043] Please see Figures 1 to 6 In one embodiment of the present invention, the material of the irregular nanocatalyst structure is at least one of metal, alloy, or metal oxide, and the material of the morphology-inducing layer 11 is at least one of metal, alloy, or metal oxide. The material of the irregular nanocatalyst structure 10 and the material of the morphology-inducing layer 11 may be the same or different. For example, a metal or alloy can be used in the hydrogen-producing cathode, and a metal oxide can be used in the oxygen-producing anode.

[0044] In one embodiment of the present invention, a method for preparing a heteromorphic nanocatalyst is provided, comprising at least steps S11-S14.

[0045] Step S11: Prepare the metal precursor solution.

[0046] Step S12: Add a morphology inducer to the metal precursor solution.

[0047] Step S13: Under alkaline conditions, the mixture is kept at a preset temperature and stirred for a preset time to obtain an intermediate.

[0048] Step S14: Clean and dry the intermediate to obtain the irregular nanocatalyst.

[0049] In one embodiment of the present invention, in step S11, the metal precursor solution contains at least two of the following metal elements: transition metals, lanthanide rare earth elements, and platinum group noble metals. The transition metal elements include, for example, at least one of Mn, Cr, Zr, Fe, Co, Ni, Cu, Zn, Mo, or W. The platinum group noble metals include at least one of Ru, Rh, Pd, Ag, Os, Ir, Pt, and Au. The solvent for the metal precursor solution includes pure water, ultrapure water, deionized water, or tap water. The metal elements are derived from water-soluble metal salts such as metal salts, metal halides, metal sulfates, or metal nitrates. The metal salt is added to the solvent, for example, by ultrasonic stirring for 2 to 5 minutes to obtain the metal precursor solution. In other embodiments, dissolution can also be achieved through other methods. The total metal ion concentration in the metal precursor solution is, for example, 0.01 to 1 M.

[0050] In one embodiment of the present invention, in step S12, in order to obtain heteromorphic nanocatalysts of different shapes, a morphology inducer is added. The morphology inducer is selected, for example, from isophthalic acid esters, phthalates, 1,4-diazabicyclo[2.2.2]octane, triethylenediamine, 1,4-dimethylpiperazine, hexamethylenetetramine, pyromellitic acid, pyromellitic tricarboxylic acid, 1,4-bis(1H-pyrazol-4-yl)benzene, 1,4,7,10-tetraazacyclododecane-1,4,7,10-tetracarboxylic acid, 2,4,6-tris(4-pyridyl)-1, At least one of the following: 3,5-triazine, tris(isobutylaminoethyl)amine, bis(3,5-dicarboxyphenyl)azo, biphenylcarboxylic acid, 2,5-dihydroxyterephthalic acid, 2,6-naphthalenedicarboxylic acid, 1,4-phenylene diacetic acid, 1,1,2,2-tetra(4-carboxyphenyl)ethylene, 1,3,5-tris(4-carboxyphenyl)benzene, 2-(diphenylphosphino)terephthalic acid, 2-amino-4-hydroxy-6-methylpyrimidine, 2-methylimidazolium, 2-aminoterephthalic acid, terephthalic acid, fumaric acid, and trioctyl trimellitate. The molar ratio of the organic inducer to the total metal ion concentration in the metal precursor solution is, for example, 1:10000 to 100:1.

[0051] In one embodiment of the present invention, in step S12, the metal precursor solution and the morphology inducer are mixed uniformly, for example, by ultrasonic stirring, for a time of 2 to 5 minutes. In other embodiments, mixing can also be performed by other methods.

[0052] In one embodiment of the present invention, different metal precursor solutions and morphology inducers are selected according to the predetermined morphology or performance requirements of the desired shaped nanocatalyst, thereby achieving different morphological requirements. That is, by controlling the reaction raw materials and reaction conditions, shaped nanocatalysts with predetermined morphological requirements can be obtained.

[0053] In one embodiment of the present invention, in step S13, under alkaline conditions, the mixture is kept at a preset temperature and stirred for a preset time to obtain an intermediate. In another embodiment, for example, an alkaline substance such as ammonia or potassium hydroxide is added to a mixed solution of a metal precursor solution and a morphology inducer, and the pH value is controlled at 8–14. The mixture is then kept at a preset temperature and stirred to obtain solid intermediates with different morphologies. In another embodiment, the preset temperature is, for example, 40°C–90°C, and the preset time is, for example, 5 min–1200 min. Under alkaline conditions, the morphology inducer induces the metal precursor to first form a heteromorphic nanocatalyst structure with a preset morphology. A morphology-inducing layer is then formed in situ on a portion of the surface of the heteromorphic nanocatalyst structure, thereby obtaining a heteromorphic nanocatalyst.

[0054] In one embodiment of the present invention, in step S14, after the solid intermediate is formed, the intermediate is subjected to steps such as washing, collecting, and drying to remove impurities from the intermediate. In this embodiment, for example, deionization is used for rinsing, and the rinsed intermediate is collected, for example, dried at 80°C and stored to obtain a heteromorphic nanocatalyst.

[0055] In one embodiment of the present invention, to obtain a heteromorphic nanocatalyst with multiple morphology-inducing layers, after obtaining the heteromorphic nanocatalyst, steps S11-S14 are repeated. In step S11 or S13, the previously obtained heteromorphic nanocatalyst is added to grow morphology-inducing layers in situ on the heteromorphic nanocatalyst, thereby obtaining a heteromorphic nanocatalyst with multiple morphology-inducing layers. The material of the multiple morphology-inducing layers can be exactly the same as the material of the heteromorphic nanocatalyst structure, or it can be partially or completely different.

[0056] The following specific examples illustrate the present invention in detail. It should also be understood that the following examples are only for specific illustrative purposes and should not be construed as limiting the scope of protection of the present invention. Any non-essential improvements and adjustments made by those skilled in the art based on the above description of the present invention are within the scope of protection of the present invention. The specific process parameters, etc., in the following examples are merely examples within a suitable range; that is, those skilled in the art can make appropriate selections within the appropriate range based on the description herein, and are not intended to be limited to the specific values ​​in the examples below.

[0057] like Figure 1 Figure 4As shown, the heteromorphic nanocatalysts of different embodiments of this application were observed using a scanning electron microscope (SEM), and the results were obtained. Figures 1 to 4 The scanning electron microscope image shown is from... Figure 1 As can be seen from Figure 2, the microstructure of the irregular nanocatalyst prepared in this embodiment is: a hexagonal irregular nanocatalyst, with a side length of, for example, 0.1 μm to 1.5 μm. As can be seen from Figure 2, the microstructure of the irregular nanocatalyst prepared in this embodiment is: a needle-shaped irregular nanocatalyst, with a nanocatalyst structure length of, for example, 0.2 μm to 5 μm. Figure 3 It can be seen that the microstructure of the irregular nanocatalyst prepared in this embodiment is: a pointed prismatic irregular nanocatalyst, and the length of the nanocatalyst structure is, for example, 0.01 μm to 2 μm. From Figure 4 As can be seen, the microstructure of the heteromorphic nanocatalyst prepared in this embodiment is: a fused spherical heteromorphic nanocatalyst, with the diameter of the sphere being, for example, 0.01 μm to 0.5 μm. That is, by selecting different metal precursors and morphology inducers, heteromorphic nanocatalysts with different morphologies can be obtained.

[0058] like Figure 5 As shown, a heteromorphic nanocatalyst of one embodiment was observed using a scanning electron microscope, yielding... Figure 5 The scanning electron microscope (SEM) image and energy-dispersive X-ray spectroscopy (EDS) image are shown. The microstructure of the heteromorphic nanocatalyst prepared in Example 5 is a chain-like structure with chain lengths ranging from 8 μm to 1000 μm; only a portion of the chain length is shown in the image. Analysis revealed that the heteromorphic nanocatalyst structure prepared in this example comprises 50% transition metal, 45% noble metal, and 5% oxygen. The material of the morphology-inducing layer is the same as that of the heteromorphic nanocatalyst structure.

[0059] like Figure 6 As shown, the shaped nanocatalyst of one embodiment was observed by scanning electron microscopy, and the scanning electron microscope image and X-ray energy dispersive spectroscopy image were obtained. It was found that the structure of the shaped nanocatalyst prepared in this embodiment includes 50% transition metal, 45% noble metal, and 5% oxygen. The material of the morphology-inducing layer is the same as the material of the shaped nanocatalyst structure.

[0060] In some embodiments, the above-described electrode catalyst can be applied in hydrogen electrolysis units or hydrogen electrolyzers, such as proton exchange membrane (PEM) electrolyzers, anion exchange membrane (AEM) electrolyzers, alkaline electrolyzers, solid oxide electrolyzers (SOEC), or other electrolyzer electrodes using catalyst electrodes. Specifically, the electrode catalyst of this application can be formed on different substrates to form electrode sheets or membrane electrodes. However, it is not limited to this; in other embodiments, the above-described electrode catalyst can also be applied to the electrodes of other electrochemical devices, such as the electrodes of fuel cells or other electrochemical electrolyzers.

[0061] This invention also provides a hydrogen production electrolyzer, comprising the aforementioned shaped nanocatalyst, wherein the shaped nanocatalyst is, for example, supported on a proton exchange membrane or anion exchange membrane to form a membrane electrode, for example, for anodic catalysis. The shaped nanocatalyst has a high specific surface area, which increases porosity, improves catalytic efficiency, and reduces production costs. In other words, the shaped nanocatalyst obtained by this invention, when applied to a proton exchange membrane water electrolysis device or an anion exchange membrane water electrolyzer, exhibits higher catalytic activity and better stability, which is beneficial for promoting the development of hydrogen production technology through water electrolysis.

[0062] Please see Figures 5 to 7 As shown, this application also provides an electrode for an electrolyzer, which includes, for example, a substrate 30, a catalyst layer 20, and a spinel-like structure layer 40. The catalyst layer 20 is on the substrate 30, and the spinel-like structure layer 40 is formed on the top of the catalyst layer 20 and protrudes away from the catalyst layer 20. In the electrode of the electrolyzer provided in this application, the catalyst layer 20 serves as the substrate supporting the spinel-like structure layer 40, which has the advantages of high integrity, low internal stress, and high catalytic activity. It can smoothly cope with complex operating conditions and better couple the fluctuating inputs of photovoltaic and wind power.

[0063] Please see Figure 4 As shown in one embodiment of this application, the substrate 30 may be, for example, a nickel mesh, nickel foam, nickel felt, carbon cloth, a diffusion layer substrate, or a porous substrate, but is not limited thereto and may be selected according to actual needs.

[0064] Please see Figures 5 to 7As shown, in one embodiment of this application, a catalyst layer 20 is disposed on a substrate 30, and the catalyst layer 20 may include a top end 201 and a bottom end 202. The bottom end 202 is in contact with the substrate 30, and the top end 201 extends from the bottom end 202 in a direction away from the substrate 30. Specifically, in one embodiment, the catalyst layer may be formed of nanowires, for example, with nanowire tips. The nanowire tips have the smallest size in the cross-sectional direction of the nanowires, and the nanowire tips are, for example, the top end 201, disposed away from the substrate 30. The nanowires may be metal nanowires. Specifically, in this embodiment, the nanowire precursor is, for example, NiCo nanowires. In the cross-sectional direction of the nanowire precursor, the size of the nanowire precursor is, for example, 2μm-3μm, the length of the nanowire precursor is, for example, 50μm-500μm, and the size of the nanowire tip is, for example, 0.5μm-1μm.

[0065] Please see Figures 5 to 7 As shown, in one embodiment of this application, a spinel-like structure layer 40 is disposed on the top end 201 of the catalyst layer 20 and protrudes in a direction away from the catalyst layer 20. Specifically, in this embodiment, the spinel-like structure layer 40 is disposed on the tip of the nanowire and protrudes in a direction away from the catalyst layer 20. The material of the spinel-like structure layer 40 includes at least one of non-precious metal materials such as nickel, iron, or cobalt. Furthermore, the spinel-like structure layer 40 has a porous structure, so that the electrode of the electrolyzer has a large specific surface area, facilitating the entry of electrolyte into the interior of the spinel-like structure layer 40. The metal material in the spinel-like structure layer 40 acts as a catalyst, catalyzing the electrolytic hydrogen production reaction. Moreover, the porous nature of the spinel-like structure layer 40 facilitates the smooth discharge of hydrogen generated by electrolysis to the outside of the electrode of the electrolyzer, achieving rapid gas-liquid separation, reducing system resistance, and exposing more active sites. Compared with precious metal electrodes, the electrode of the electrolyzer provided in this application uses non-precious metal materials as catalysts, which has the advantages of low preparation cost and large-scale application.

[0066] This application also provides a method for preparing electrodes for an electrolytic cell, which includes at least steps S21-S24.

[0067] Step S21: Provide substrate 30.

[0068] Step S22: Form a catalyst layer 20 on the substrate 30.

[0069] Step S23: Immerse the substrate 30 with the catalyst layer 20 in the electrodeposition solution and pass a fluctuating current into the electrodeposition solution to perform electrodeposition.

[0070] Step S24: A spinel-like structure layer 40 is obtained on the top 201 of the catalyst layer 20, and the spinel-like structure layer 40 is arranged to protrude in a direction away from the catalyst layer 20.

[0071] In one embodiment of this application, after obtaining the substrate 30, a catalyst layer 20 is formed on the substrate 30 in step S22. Specifically, in this embodiment, the formation process of the catalyst layer 20 is described using nanowires as an example. This application does not limit the preparation method and type of nanowires; for example, nanowires can be prepared by spraying, coating, physical vapor deposition, chemical vapor deposition, template method, and solvothermal method. In this embodiment, the preparation process of nanowires is described, for example, by using a solvothermal method to prepare NiCo nanowires. Specifically, the nanowire preparation steps may include steps S121-S123.

[0072] Step S121: Mix the nickel source, cobalt source and urea in a solvent until homogeneous to obtain a mixed solution.

[0073] Step S122: After adding the substrate 30 to the mixed solution, heat it to a preset temperature and keep it at that temperature for a preset time to obtain the reaction product.

[0074] Step S123: The reaction product is cleaned and dried to obtain a substrate 30 loaded with nanowires.

[0075] In one embodiment of this application, in step S121, the nickel source includes, for example, at least one nickel salt such as nickel nitrate, nickel chloride, and nickel sulfate; the cobalt source includes, for example, at least one cobalt salt such as cobalt nitrate, cobalt chloride, and cobalt sulfate; the solvent is, for example, at least one deionized water, methanol, and ethanol; and the molar ratio of the nickel source, cobalt source, and urea is, for example, (0.1-0.2):(0.05-0.15):(5-10). Specifically, in this embodiment, the nickel source is, for example, nickel nitrate hexahydrate; the cobalt source is, for example, cobalt nitrate hexahydrate; and the molar ratio of the nickel source, cobalt source, and urea is, for example, 0.15:0.1:7.2.

[0076] In one embodiment of this application, after obtaining the mixed solution, in step S122, the substrate 30 is added to the mixed solution, for example, placed in a hydrothermal reactor, and then the hydrothermal reactor, substrate, and mixed solution are heated to a preset temperature and held at that temperature for a preset time to obtain the reaction product. The preset temperature is, for example, 70℃-200℃, and the preset time is, for example, 2h-6h. Specifically, at the preset temperature, a nickel source, a cobalt source, and urea react to form NiCo nanowires on the substrate 30. The nanowire tips of the NiCo nanowires are positioned away from the substrate 30. Due to incomplete reactions and the presence of solvents, the surfaces of the nanowires and the substrate 30 contain impurities such as cobalt source, nickel source, urea, and solvents.

[0077] In one embodiment of this application, after obtaining the reaction product, in step S123, the reaction product is filtered to obtain nanowires and a substrate 30. Then, the surfaces of the nanowires and substrate 30 are cleaned with a cleaning agent to remove residual nickel source, cobalt source, urea, and solvent. After cleaning, the nanowires and substrate 30 are vacuum dried to remove the cleaning agent and solvent from the surface, obtaining a substrate 30 loaded with nanowires. The cleaning agent includes, for example, at least one of deionized water, methanol, and ethanol, and the vacuum drying temperature is, for example, 50°C-120°C.

[0078] In one embodiment of this application, after obtaining the nanowires and substrate 30, in steps S23 and S24, the substrate 30 with nanowires is immersed in an electrodeposition solution, and a fluctuating current is passed through the electrodeposition solution. The metal ions in the electrodeposition solution are reduced to metal atoms and electrodeposited on the nanowires. Furthermore, during the electrodeposition process, due to the current concentration phenomenon, the current tends to concentrate on the tip of the nanowire, and the electrode spacing at the tip of the nanowire is small. Therefore, metal atoms tend to deposit on the tip of the nanowire, thereby obtaining a spinel-like structure layer 40 on the tip of the nanowire, and the spinel-like structure layer 40 protrudes in a direction away from the nanowire. The electrodeposition solution includes, for example, at least one of nickel sulfate, nickel chloride, nickel sulfamate, nickel nitrate, ferrous sulfate, ferrous chloride, cobalt sulfate, cobalt nitrate, or cobalt chloride; the waveform of the fluctuating current includes, for example, at least one of square wave, ramp wave, triangular wave, or sine wave; the fluctuating period of the fluctuating current is, for example, 0.5h-2h; the peak value of the fluctuating current is, for example, 15A-20A; and the valley value is, for example, 1A-5A.

[0079] In some embodiments, multiple electrodeposited layers may be formed, for example, multiple electrodeposited layers may be stacked on a substrate. In some embodiments, the electrodeposited layers may also be formed directly on the diffusion layer 102 and / or the substrate 30, serving as the catalyst layer 20.

[0080] This application also provides an embodiment and a comparative example. The embodiment is the electrode of the electrolytic cell provided in this application, and in the embodiment, the substrate 30 is, for example, a nickel mesh, the nanowires are, for example, NiCo nanowires, the diameter of the nanowires is, for example, 2μm-3μm, the diameter of the nanowire tips is, for example, 0.5μm-1μm, and the material of the spinel-like structure layer 40 includes nickel. The comparative example is a Raney nickel electrode, and in the Raney nickel electrode of the comparative example, the mass content of nickel is, for example, 85wt%, and the mass content of aluminum is, for example, 15wt%. The electrochemical performance of the electrodes of the embodiment and the comparative example is then tested. Specifically, using the electrode from the examples or comparative examples as the working electrode, a 1 mol / L potassium hydroxide solution as the electrolyte, and at 25°C, an Hg / HgO electrode as the reference electrode and a nickel mesh electrode as the counter electrode, a linearly varying voltage is applied to the working electrode using linear sweep voltammetry. The change in electrolytic current of the working electrode with voltage is measured, and a linear sweep voltammetry diagram is plotted based on the changes. Then, by analyzing the linear sweep voltammetry diagram, the overpotential of the working electrode is obtained, and the hydrogen evolution performance of the working electrode is evaluated based on the overpotential.

[0081] Please see Figure 8 As shown, in one embodiment of this application, based on the linear scan voltammetry of the two working electrodes in the embodiment and comparative examples, it can be concluded that at 3000 A / m 2 In the example, the overpotential of the electrode in the electrolyzer is, for example, 220 mV, while the overpotential of the Raney nickel electrode in the comparative example is, for example, 375 mV. Comparing the overpotentials of the two electrodes, it can be seen that the overpotential of the electrode in the example is lower than that of the Raney nickel electrode in the comparative example, indicating that the electrode in the example has better catalytic ability and activity for the hydrogen evolution reaction compared to the Raney nickel electrode in the comparative example. Therefore, the electrode of the electrolyzer provided in this application has advantages such as high integrity, low internal stress, and high catalytic activity, enabling it to smoothly cope with complex operating conditions and better couple the fluctuating inputs of photovoltaic and wind power.

[0082] This application also provides an electrolytic cell, comprising at least a hydrogen evolution catalytic electrode, an oxygen evolution catalytic electrode, and a membrane. The hydrogen evolution catalytic electrode is the same as the electrode in the aforementioned electrolytic cell, and will not be elaborated upon here. The oxygen evolution catalytic electrode is disposed on one side of the electrode in the electrolytic cell, and the membrane is disposed between the electrode and the oxygen evolution catalytic electrode to prevent the hydrogen produced by the electrolytic electrolysis of the electrode in the electrolytic cell from mixing with the oxygen produced by the electrolytic electrolysis of the oxygen evolution catalytic electrode. Furthermore, this application does not limit the types of oxygen evolution catalytic electrode and membrane, and they can be selected according to actual needs. In the electrolytic cell provided by this application, the electrodes of the electrolytic cell have high catalytic activity for the hydrogen evolution reaction, thereby improving the efficiency and yield of hydrogen production by electrolysis, and can be widely applied, for example, it can be used in high-electric-density electrolytic cells.

[0083] In one embodiment of this application, the membrane is, for example, a polyphenylene sulfide (PPS) membrane, an organic-inorganic composite membrane, or a hydroxide ion exchange membrane. The thickness of the PPS membrane is, for example, 0.5 mm to 1 mm, and the thickness of the organic-inorganic composite membrane is, for example, 0.2 mm to 0.8 mm.

[0084] It is worth noting that the electrode and catalyst layer 20 of this application can be applied in electrolyzers suitable for catalyst electrodes, such as proton exchange membrane (PEM) electrolyzers, anion exchange membrane (AEM) electrolyzers, alkaline electrolyzers, solid oxide electrolyzers (SOEC), seawater electrolyzers, and high-current-density (e.g., 6,000 A / m) electrolyzers. 2 Above or 10,000 A / m 2 In the above-mentioned electrolytic cells, chlorine-producing electrolytic cells, salt-precipitating electrolytic cells, chlor-alkali electrolytic cells, hydrogen-producing electrolytic cells, or other electrolytic cells using catalyst electrodes. In this case, the electrolysis device (such as an electrolytic cell) or system using the catalyst of this application may include a membrane layer 101, a diffusion layer 102, and a catalyst layer 20, wherein the catalyst layer 20 is located between the membrane layer 101 and the diffusion layer 102.

[0085] In some embodiments, such as Figure 9 As shown, the catalyst layer 20 of this application can be applied in an electrolyzer, which includes a membrane layer 101, at least two diffusion layers 102, and a catalyst layer 20. The diffusion layers 102 are located on opposite sides of the membrane layer 101. The catalyst layer 20 is formed between the membrane layer 101 and the diffusion layers 102. In one embodiment, the catalyst layer 20 may be formed on one side surface of the diffusion layer 102, close to the membrane layer 101. In another embodiment, the catalyst layer 20 may also be formed on both sides of the diffusion layer 102. In yet another embodiment, the catalyst layer 20 may be formed on both sides of the membrane layer 101. It is worth noting that the membrane layer 101 can be a diaphragm, proton exchange membrane (PEM), anion exchange membrane, bipolar membrane, cation exchange membrane, or other membranes used for electrolysis, and the diffusion layer 102 can be a nickel mesh, nickel foam, nickel felt, carbon cloth, a diffusion layer substrate, or a porous substrate, etc.

[0086] In some embodiments, such as Figure 9 As shown, the electrolytic cell (or electrolytic device) of this application may include multiple electrolytic units (or electrolytic chambers), and each electrolytic unit may include a membrane layer 101, at least two electrodes and a catalyst layer 20.

[0087] In some embodiments, such as Figure 10As shown, the catalyst layer 20 of this application can be applied in an electrolytic cell, which may include a film layer 101, at least two diffusion layers 102, at least two electrode plates 103, and an electrode plate 104. The diffusion layers 102 are located on opposite sides of the film layer 101. The electrode plates 103 are formed between the film layer 101 and the diffusion layers 102. The electrode plates 103 may be anode electrode plates and cathode electrode plates, and the electrode plates 103 may include the catalyst layer 20 and a substrate 30. The catalyst layer 20 may be formed on one side surface of the substrate 30 and close to the film layer 101, or the catalyst layer 20 may be formed on both sides of the substrate 30 to form cathode or anode electrode plates.

[0088] It is worth noting that the membrane layer 101 can be a diaphragm, proton exchange membrane (PEM), anion exchange membrane, bipolar membrane, cation exchange membrane, or other membrane layers used for electrolysis, and the diffusion layer 102 and / or substrate 30 can be a nickel mesh, nickel foam, nickel felt, carbon cloth, diffusion layer substrate, or porous substrate, etc. In some embodiments, Figure 10 The substrate 30 of the intermediate electrode sheet can also serve as a diffusion layer.

[0089] In one embodiment, such as Figure 11 As shown, the electrolyzer is, for example, an AEM electrolyzer, which may include a membrane layer 101, at least two diffusion layers 102, at least two catalyst layers 20, and electrode plates 104. The diffusion layers 102 are located on opposite sides of the membrane layer 101. The membrane layer 101 is an anion exchange membrane. The catalyst layers 20 are formed on the surface of the diffusion layers 102, close to the membrane layer 101. Alternatively, the catalyst layers 20 may be formed on both sides of the diffusion layers 102, serving as an anode electrode and a cathode electrode, respectively. The anode electrode may also include a hydrogen removal layer 105, which is formed on the catalyst layer 20 on the anode side, close to the membrane layer 101, to remove hydrogen leaked to the anode side. The catalyst layer 20 and / or the hydrogen removal layer 105 may be formed by coating, spraying, thermal spraying, blade coating, spin coating, printing, heat treatment, in-situ growth, electrodeposition, vapor deposition, transfer printing, or dip coating.

[0090] In different embodiments, such as Figure 12-15As shown, the cross-sectional structure of the catalyst layer 20 can have different structures or textures, such as a sheet-like stacked structure, a porous structure, a filamentous textured structure, a particle stacked structure, a coral-like textured structure, or other cross-sectional structures or textures. In one embodiment, the catalyst layer 20 can have different structural textures in different regions. Specifically, in one embodiment, the catalyst layer 20 may include a plurality of first catalyst regions 201 and a plurality of second catalyst regions 202, wherein the structural texture of the catalyst layer 20 in the first catalyst regions 201 is different from that in the second catalyst regions 202. However, it is not limited to this; in one embodiment, the catalyst layer 20 may also include a third catalyst region or more catalyst regions with different structures or textures.

[0091] In different embodiments, such as Figure 14-15 As shown, the catalyst structure of the catalyst layer 20 can have different growth directions. Specifically, the growth direction of the catalyst structure in the first catalyst region 201 of the catalyst layer 20 is different from the growth direction of the catalyst structure in the second catalyst region 202. For example, the angle between the growth direction of the catalyst structure in the first catalyst region and the substrate is between 45 degrees and 90 degrees, or the angle between the growth direction of the catalyst structure in the first catalyst region and the substrate is between 0.1 degrees and 45 degrees. However, this is not the only possibility. In some embodiments, the catalyst layer 20 may include more variations in the growth direction of the catalyst structure. The catalyst layer 20 can be formed by methods such as coating, spraying, thermal spraying, blade coating, spin coating, printing, heat treatment, in-situ growth, electrodeposition, vapor deposition, transfer printing, and dip coating.

[0092] In one embodiment, the growth direction of the catalyst structure can be altered, for example, by selective printing, coating, or spraying process conditions or directions. In one embodiment, the growth direction of the catalyst structure can be altered, for example, by heat treatment process conditions (e.g., slowing diffusion growth rate through low temperature, annealing) or heating location. In one embodiment, the addition of specific surfactants or ligands (e.g., carboxylic acids, amines) can promote the growth of the catalyst structure in other directions. In one embodiment, the morphology of metal nanoparticles and the growth direction of the catalyst structure can be controlled, for example, by electric fields, magnetic fields, or light fields (e.g., photochemical reduction). In one embodiment, the precursor concentration can be adjusted to promote anisotropic growth (e.g., nanowires) through low concentration. In one embodiment, a template (e.g., porous alumina, silica) can be used to confine the growth space or guide the directional alignment of the catalyst structure.

[0093] In different embodiments, such as Figure 12-13As shown, the first catalyst region 201 and / or the second catalyst region 202 are, for example, strip-shaped regions, and the width of the first catalyst region 201 and / or the second catalyst region 202 is, for example, 0.1 to 5 mm, or, for example, 0.3 to 2.5 mm. The first catalyst region 201 and the second catalyst region 202 can be arranged in an alternating pattern, for example, the first catalyst region 201 and the second catalyst region 202 can be arranged in an alternating pattern or in a striped pattern with arbitrary arrangement. However, it is not limited to this, the first catalyst region 201 and / or the second catalyst region 202 can also be, for example, grid-shaped, spot-shaped, concentric circle-shaped, wavy, or other any suitable combination of shapes.

[0094] In different embodiments, multiple microchannels 203 may be formed between the first catalyst region 201 and / or the second catalyst region 202. Specifically, the microchannels 203 may be formed between multiple first catalyst regions 201 or multiple second catalyst regions 202, or the microchannels 203 may be formed between the first catalyst region 201 and the second catalyst region 202. The width of the microchannels 203 may be 0.01–5 mm, for example, 0.01–1 mm, or even 0.1–0.9 mm. The microchannels 203 may expose a portion of the surface of the substrate 30 for rapid diffusion and transport of the gas generated by electrolysis.

[0095] Catalyst regions with different structures or textures can increase the active sites of the catalyst layer 20 and effectively disperse the distribution of active catalyst on the substrate, avoiding excessive agglomeration in local areas and effectively improving the utilization rate of precious metals. Furthermore, the microchannels 203 can also improve electrode performance and reduce the amount of precious metals used (cost).

[0096] In some embodiments, as Figure 16-17As shown, before forming the catalyst layer 20 on the diffusion layer 102 or the substrate 30, a surface treatment layer 106 can be formed on the surface of the diffusion layer 102 and / or the substrate 30, and then the catalyst layer 20 can be formed on the surface treatment layer 106. This is to ensure the stability of the catalyst layer 20 on the diffusion layer 102 and / or the substrate 30, making the catalyst layer 20 less likely to fall off, thus ensuring the performance and stability of the electrode sheet. The surface treatment layer 106 can be formed on the surface of the diffusion layer 102 and / or the substrate 30 by means of coating, spraying, thermal spraying, scraping, spin coating, printing, heat treatment, in-situ growth, electrodeposition, vapor deposition, transfer printing, dip coating, etc. The material of the surface treatment layer 106 can be the same as or partially the same as the material of the catalyst layer 20, the diffusion layer 102, and / or the substrate 30. The surface roughness of the surface treatment layer 106 can be greater than that of the diffusion layer 102 and the substrate 30. The surface roughness of the surface treatment layer 106 can be 1μm-50μm, for example, 10μm-50μm, or even 20μm-45μm. The specific surface area of ​​the surface treatment layer 106 can be, for example, greater than or equal to 10m². 2 / g, for example, 15m 2 / g-30m 2 The surface area of ​​the surface treatment layer 106 can be greater than that of the diffusion layer 102 and the substrate 30, and the surface stress of the surface treatment layer 106 can be less than that of the diffusion layer 102 and the substrate 30.

[0097] The surface treatment layer 106 can alter the surface structure and / or surface properties of the diffusion layer 102 or the substrate 30. For example, the surface treatment layer 106 can have a porous structure to increase the surface area of ​​the subsequent electrode, exposing more active sites and accelerating the diffusion and reaction process of reactants, thereby effectively improving the electrochemical performance of the electrode. Furthermore, the surface treatment layer 106 can reduce the internal stress of the subsequent electrode and significantly improve the electrode sheet's resistance to current fluctuations.

[0098] In one embodiment, such as Figure 17 As shown, the surface treatment layer 106 may include, for example, an island-like structure composed of nanoparticles, but is not limited thereto. The surface structure of the surface treatment layer 106 may include, for example, one or a combination of several of the following: polyhedral, needle-like, pointed prism-like, spherical, coral-like, sheet-like, porous, hollow spherical, chain-like, fused spherical, or irregular shapes. In one embodiment, the surface of a specific diffusion layer 102 and the substrate 30 may also be selectively etched by an oxidant or acid to form the surface treatment layer 106.

[0099] In some embodiments, such as Figure 18As shown, a structural layer grown on one side of the diffusion layer 102 and / or the substrate 30, and near or far from the film layer 101 (or located between the diffusion layer 102 and the electrode 104), can serve as a support layer 107 to support the space between the diffusion layer 102 and the electrode 104. This support layer 107 can be formed by the catalyst layer 20 or the surface treatment layer 106. However, it is not limited to these methods; the support layer 107 can also be additionally provided and different from the catalyst layer 20 or the surface treatment layer 106. The support layer 107 can be formed on the diffusion layer 102 and / or the substrate 30 by methods such as coating, spraying, thermal spraying, blade coating, spin coating, printing, heat treatment, in-situ growth, electrodeposition, vapor deposition, transfer printing, or dip coating.

[0100] In various embodiments, the above-mentioned electrode catalyst can be applied in electrolysis units or electrolyzers, such as proton exchange membrane (PEM) electrolyzers, anion exchange membrane (AEM) electrolyzers, alkaline electrolyzers, solid oxide electrolyzers (SOEC), seawater electrolyzers, and high-voltage electrolyzers (e.g., 6,000 A / m). 2 Above or 10,000 A / m 2 The above-mentioned electrode catalysts can be used in the electrodes of electrolyzers, chlorine-producing electrolyzers, salt-precipitating electrolyzers, chlor-alkali electrolyzers, hydrogen-producing electrolyzers, or other electrolyzers that use catalyst electrodes. Specifically, the electrode catalysts of this application can be formed on different substrates to form electrode sheets or membrane electrodes. However, this is not the only possibility. In other embodiments, the above-mentioned electrode catalysts can also be applied to the electrodes of other electrochemical devices, such as the electrodes of fuel cells or other electrochemical electrolyzers.

[0101] In some embodiments, this application also provides an electrolyzer including the electrode catalyst described above, wherein the electrode catalyst is, for example, supported on a proton exchange membrane or anion exchange membrane to form a membrane electrode, for example, for cathode or anode catalysis. The electrode catalyst has a high electrochemical surface area, high exposure of active sites, and a large number of mass transfer channels, which can improve catalytic efficiency and reduce production costs. That is, in the electrolysis device of this application, the catalytic activity is higher and the stability is better, which is beneficial to promoting the development of electrolytic hydrogen or chlorine production technology. The above embodiments are merely illustrative of the principles and effects of the present invention and are not intended to limit the present invention. Any person skilled in the art can modify or change the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or changes made by those skilled in the art without departing from the spirit and technical concept disclosed in the present invention should still be covered by the claims of the present invention.

Claims

1. A heteromorphic nanocatalyst, characterized in that, include: heterogeneous nanocatalyst structures; and A morphology-inducing layer is formed on a portion of the surface of the heteromorphic nanocatalyst structure.

2. The heteromorphic nanocatalyst according to claim 1, characterized in that, The shape of the heteromorphic nanocatalyst structure is one or a combination of several of the following: polyhedral, needle-shaped, pointed prism, spherical, chain-like, or fused spherical.

3. The heteromorphic nanocatalyst according to claim 1, characterized in that, The morphology-inducing layer is at least one layer. When the morphology-inducing layer is multi-layered, the multiple morphology-inducing layers are sequentially stacked on the irregular nanocatalyst structure.

4. The heteromorphic nanocatalyst according to claim 1, characterized in that, The material of the heteromorphic nanocatalyst structure is at least one of metal, alloy or metal oxide, and the material of the morphology-inducing layer is at least one of metal, alloy or metal oxide.

5. The heteromorphic nanocatalyst according to claim 1, characterized in that, The heteromorphic nanocatalyst comprises at least two of transition metals, lanthanide rare earth elements, and platinum group noble metals, wherein the transition metal element comprises at least one of Mn, Cr, Zr, Fe, Co, Ni, Cu, Zn, Mo, or W, and the platinum group noble metal element comprises at least one of Ru, Rh, Pd, Ag, Os, Ir, Pt, or Au.

6. A method for preparing the heteromorphic nanocatalyst according to any one of claims 1-5, characterized in that, At least including: Preparation of metal precursor solutions; A morphology inducer is added to the metal precursor solution; Under alkaline conditions, the mixture is stirred at a preset temperature for a preset time to obtain an intermediate. as well as The intermediate was cleaned and dried to obtain a heteromorphic nanocatalyst.

7. The method for preparing the heteromorphic nanocatalyst according to claim 6, characterized in that, The morphology inducers include isophthalic acid esters, phthalates, 1,4-diazabicyclo[2.2.2]octane, triethylenediamine, 1,4-dimethylpiperazine, hexamethylenetetramine, pyromellitic acid, pyromellitic tricarboxylic acid, 1,4-bis(1H-pyrazol-4-yl)benzene, 1,4,7,10-tetraazacyclododecane-1,4,7,10-tetracarboxylic acid, 2,4,6-tris(4-pyridyl)-1,3,5-triazine, tris(isobutylaminoethyl)amine, bis( At least one of the following: 3,5-dicarboxyphenyl azo, biphenyl phthalic acid, 2,5-dihydroxyterephthalic acid, 2,6-naphthalenedicarboxylic acid, 1,4-phenylene diacetic acid, 1,1,2,2-tetra(4-carboxyphenyl)ethylene, 1,3,5-tris(4-carboxyphenyl)benzene, 2-(diphenylphosphino)terephthalic acid, 2-amino-4-hydroxy-6-methylpyrimidine, 2-methylimidazole, 2-aminoterephthalic acid, terephthalic acid, fumaric acid, and trioctyl trimellitate.

8. The method for preparing the heteromorphic nanocatalyst according to claim 6, characterized in that, The preparation method further includes repeating the formation steps of the shaped nanocatalyst to obtain the shaped nanocatalyst with multiple morphology-inducing layers.

9. An electrode for a hydrogen electrolyzer, characterized in that, include: The substrate and the electrode catalyst according to claim 1.

10. A hydrogen production electrolyzer, characterized in that, Includes the electrode as described in claim 9.

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