A bimetallic catalyst for seawater electrolysis, a hydrogen evolution electrode, its preparation method, and its application.
By loading Ni3S4 and CoS nanosheet catalysts onto a nickel foam substrate, the problems of insufficient catalyst activity and poor stability in seawater electrolysis for hydrogen production were solved, realizing a low-energy-consumption and high-efficiency seawater electrolysis hydrogen production process.
Patent Information
- Application Number
- CN202111530276.7
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- Filing Date
- 2021-12-15
- Publication Date
- 2025-11-14
- Estimated Expiration
- 2041-12-15
AI Technical Summary
Existing catalysts for hydrogen production by seawater electrolysis have insufficient activity and poor stability, resulting in high energy consumption and low efficiency in the electrolysis process, especially under alkaline conditions where the catalyst activity kinetics are slow.
A bimetallic catalyst, Ni3S4, and CoS coated with a carbon-nitrogen layer were loaded onto a nickel foam substrate through in-situ growth and chemical vapor deposition to form a flower-like nanosheet structure, which enhances the catalytic active sites and hydrophilicity.
Under alkaline seawater conditions, the catalyst exhibits low hydrogen evolution overpotential and high stability, supporting stable operation at high current densities and reducing energy consumption for hydrogen production through seawater electrolysis.
Smart Images
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Abstract
Description
Technical Field
[0001] This application belongs to the technical field of hydrogen production by water electrolysis, specifically relating to a bimetallic catalyst for seawater electrolysis, a hydrogen evolution electrode, its preparation method, and its application. Background Technology
[0002] With the continuous depletion of non-renewable energy sources, environmental pollution, and the increasing energy demand year by year, developing new clean and renewable energy sources is a feasible solution to the energy crisis. Hydrogen energy has attracted widespread attention due to its high calorific value, clean and pollution-free operation, and wide availability, and is considered the most promising next-generation clean energy source. Currently, industrial hydrogen production methods mainly include coal gasification, methane reforming, methanol reforming, and water electrolysis. However, these methods still heavily rely on fossil fuel combustion, which fails to address the air pollution caused by large CO2 emissions. Water electrolysis for hydrogen production uses water as feedstock and produces hydrogen and oxygen, enabling efficient hydrogen production and recycling. Due to its simple process, environmental friendliness, and high product purity, water electrolysis is the most promising hydrogen production method. Currently, water electrolysis technology is mainly based on freshwater electrolysis; however, freshwater resources account for less than 3%, while seawater resources account for approximately 97%. Therefore, to protect our vital freshwater resources, seawater electrolysis will provide a possibility for large-scale hydrogen production.
[0003] Because seawater contains Cl - Ca 2+ Mg 2+ Including organic matter, the reaction system becomes more complex, leading to challenges in direct seawater electrolysis such as competing reactions with the chlorohydrin (CER), corrosion from chloride oxides, low conductivity, solid precipitate formation, and biofouling. Currently, to better address these issues, seawater electrolysis is mostly conducted under alkaline conditions. However, alkaline conditions are unfavorable for the hydrogen evolution reaction, resulting in slow kinetics, reduced catalyst stability, and higher overpotentials during the electrolysis process. This, in turn, increases energy consumption and reduces electrical energy conversion efficiency.
[0004] Developing highly active cathode catalysts is a key technological means to solve the problems of high hydrogen evolution overpotential and poor stability in seawater electrolysis. Currently, the catalysts used for water electrolysis are mainly noble metal-based and transition metal-based catalysts. Although noble metal materials are currently the most ideal HER and OER catalysts, their high price, limited reserves, and poor stability restrict their large-scale production in the energy sector. Transition metal-based catalysts, due to their abundant reserves, low cost, and rich active sites, have become a research hotspot in water electrolysis catalytic systems in recent years. However, transition metal-based catalysts still face challenges such as insufficient catalyst activity and poor stability under seawater conditions, and the adsorption of insoluble calcium hydroxide / magnesium hydroxide on the cathode catalyst surface during electrolysis, which covers the active sites and reduces the catalyst's reactivity and stability. Therefore, developing a highly active and stable hydrogen evolution catalyst is of great significance for the development of seawater electrolysis hydrogen production technology. Summary of the Invention
[0005] The purpose of this application is to address the problems of insufficient activity and poor stability of catalysts for hydrogen evolution through seawater electrolysis. This application describes the preparation of a bimetallic sulfide catalyst and its application in hydrogen production through seawater electrolysis.
[0006] According to one aspect of this application, a bimetallic catalyst for seawater electrolysis is provided, comprising Ni3S4 coated with a carbon-nitrogen layer and CoS coated with a carbon-nitrogen layer;
[0007] The content of Ni3S4 is 10-20 wt%;
[0008] The content of CoS is 30-40 wt%;
[0009] The bimetallic catalyst comprises at least one of two crystalline phases in one crystal lattice.
[0010] The thickness of the carbon-nitrogen layer is 0.5–1 nm.
[0011] The bimetallic catalyst has a flower-like morphology;
[0012] The lateral dimensions of the nanosheets are 80–120 nm.
[0013] According to another aspect of this application, a method for preparing the above-mentioned bimetallic catalyst for seawater electrolysis is provided, comprising at least the following steps:
[0014] The raw materials containing nickel source, cobalt source and urea are mixed with water to obtain a mixed solution, which is then reacted and calcined with a sulfur source to obtain the bimetallic hydrogen evolution catalyst.
[0015] The nickel source is selected from at least one of nickel foam, nickel nitrate, or nickel chloride;
[0016] The cobalt source is selected from at least one of cobalt nitrate, cobalt acetate, or cobalt chloride;
[0017] The sulfur source is selected from at least one of sulfur, thiourea, or thioacetamide;
[0018] The molar ratio of the nickel source, cobalt source, sulfur source, urea, and water is 1:1:1:2:30 to 1:3:3:5:50.
[0019] The raw materials include a buffer;
[0020] The buffer is selected from at least one of ammonium fluoride, ammonium chloride, or sodium acetate;
[0021] The pH value of the mixed solution is 6 to 8.
[0022] The reaction temperature is 120–150°C;
[0023] The reaction time is 8 to 10 hours.
[0024] The calcination atmosphere is a non-reactive gas atmosphere;
[0025] The inactive gas is selected from at least one of nitrogen, helium, or argon;
[0026] The roasting process includes heating to 300-450°C at a heating rate of 1-5°C / min and holding for 1-2 hours;
[0027] The process involves drying before roasting;
[0028] The drying temperature is 60–80°C;
[0029] The drying time is 8 to 12 hours.
[0030] According to another aspect of this application, a hydrogen evolution electrode is provided, comprising a substrate and a catalyst supported on the surface of the substrate;
[0031] The catalyst is selected from the bimetallic catalyst for seawater electrolysis described above or the bimetallic catalyst for seawater electrolysis prepared by the above preparation method.
[0032] The matrix is selected from at least one of nickel foam, copper foam, or carbon paper;
[0033] In the hydrogen evolution electrode, the catalyst loading is 20–50 wt%.
[0034] According to another aspect of this application, a method for preparing the above-mentioned hydrogen evolution electrode is provided, including an impregnation method or a coating method.
[0035] Specifically, it includes the following processes:
[0036] A. Pretreatment of nickel foam substrate: First, commercial nickel foam with an area of 3×4cm is ultrasonically cleaned with 1M HCl, acetone and water in sequence to remove oxides and organic matter on the surface, and then placed in a vacuum oven to dry.
[0037] B. Preparation of the reaction precursor solution: Weigh a certain amount of cobalt salt, urea and ammonium fluoride in sequence and place them in the liner of the reaction vessel. Add an appropriate amount of deionized water and stir magnetically to form a homogeneous solution.
[0038] C. Preparation of reaction precursor: The pretreated nickel foam from (1) was placed in the solution from (2) and reacted at a constant temperature in a high-pressure reactor. After the reaction was completed, it was naturally cooled to room temperature. The reacted nickel foam was then removed, washed repeatedly with deionized water to remove residual ions on the surface, and dried in a vacuum oven.
[0039] D. Preparation of hydrogen evolution electrode: Weigh an appropriate amount of sulfur-containing compound and place it together with the precursor in (3) into a tube furnace. Under the N2 gas atmosphere, heat it to a certain temperature and hold it for several hours. Then cool it to room temperature to obtain the hydrogen evolution electrode.
[0040] According to another aspect of this application, a method for electrolyzing seawater is provided, using the hydrogen evolution electrode described above or the hydrogen evolution electrode prepared by the above preparation method;
[0041] Current density is 100 mA / cm 2 The overpotential is 149mV;
[0042] Current density is 500 mA / cm 2 The overpotential is 250mV.
[0043] Compared with the prior art, this application has the following advantages:
[0044] (1) This application employs a combination of in-situ growth and chemical vapor deposition techniques to load a nitrogen-doped carbon-uniformly coated nickel-cobalt-sulfur catalyst onto a nickel foam substrate. Studies have shown that the nickel-cobalt-sulfur catalyst is composed of a unique heterostructure Ni3S4 / CoS nanocatalyst. The interface between the two heterostructures possesses numerous reactive sites, effectively promoting the efficient dissociation of water. The uniformly coated nitrogen-doped carbon exhibits good hydrophilicity, facilitating rapid electrolyte diffusion and preventing the nickel-cobalt-sulfur catalyst from rapidly detaching from the nickel foam substrate during rapid bubble release.
[0045] (2) The nitrogen-doped carbon-coated nickel-cobalt-sulfur catalyst prepared in this application exhibits a very small hydrogen evolution overpotential (100 and 500 mA / cm under 1M KOH seawater electrolyte conditions). 2The overpotentials at current densities were 149 mV and 250 mV, respectively, and at 100 mA / cm²... 2 It can operate stably under high current density. The process described in this application is simple, and the raw materials are inexpensive and widely available, which can promote the further development of large-scale, low-energy-consumption seawater electrolysis hydrogen production technology. Attached Figure Description
[0046] Figure 1 The image shows the XRD patterns of the hydrogen evolution electrode and standard card prepared in Example 6.
[0047] Figure 2 This is a scanning electron microscope image of the hydrogen evolution electrode prepared in Example 5.
[0048] Figure 3 This is a transmission electron microscope image of the hydrogen evolution electrode prepared in Example 6.
[0049] Figure 4 This is a graph showing the hydrogen evolution performance of the hydrogen evolution electrode prepared in Example 4 under different electrolyte conditions.
[0050] Figure 5 This is a stability diagram of the hydrogen evolution electrode prepared in Example 5 under alkaline seawater conditions. Detailed Implementation
[0051] The present application is described in detail below with reference to the embodiments, but the present application is not limited to these embodiments.
[0052] Unless otherwise specified, all raw materials used in the embodiments of this application were purchased through commercial channels.
[0053] The analysis method in the embodiments of this application is as follows:
[0054] Performance testing methods: Polarization curves were tested at a scan rate of 2 mV / s and a scan range of -0.9 to -1.5 V vs SCE. Stability testing was performed using a constant current at a current density of 100 mA / cm².
[0055] Characterization method: XRD test was conducted at a scan rate of 5° / min and a scan range of 10–90°.
[0056] Example 1
[0057] A. Pretreatment of nickel foam substrate: First, commercial nickel foam with an area of 3×4cm is ultrasonically cleaned with 1M HCl solution, acetone and water in sequence to remove oxides and organic matter on the surface, and then placed in a vacuum oven to dry.
[0058] B. Preparation of the reaction precursor solution: Weigh 0.8790g of cobalt nitrate, 0.9038g of urea and 0.4440g of ammonium fluoride in sequence and place them in the liner of the reaction vessel. Add 60ml of deionized water and stir magnetically to form a homogeneous solution.
[0059] C. Preparation of the reaction precursor: The pretreated nickel foam was placed in the solution in B and reacted at a constant temperature of 120°C for 10 hours in a high-pressure reactor. After the reaction was completed, it was naturally cooled to room temperature, the reacted nickel foam was removed, washed repeatedly with deionized water to remove residual ions on the surface, and then dried in a vacuum oven.
[0060] D. Preparation of hydrogen evolution electrode: Weigh 0.5g of thiourea compound and place it together with the precursor in C into a tube furnace. Under N2 atmosphere, heat to 400℃ and maintain the temperature for 2 hours. Cool to room temperature to obtain hydrogen evolution electrode.
[0061] Example 2
[0062] A. Pretreatment of nickel foam substrate: First, commercial nickel foam with an area of 3×4cm is ultrasonically cleaned with 1M HCl solution, acetone and water in sequence to remove oxides and organic matter on the surface, and then placed in a vacuum oven to dry.
[0063] B. Preparation of the reaction precursor solution: Weigh 0.8790g of cobalt nitrate, 1.8034g of urea and 0.2220g of ammonium fluoride in sequence and place them in the liner of the reaction vessel. Add an appropriate amount of deionized water and stir magnetically to form a homogeneous solution.
[0064] C. Preparation of the reaction precursor: The pretreated nickel foam was placed in the solution in B and reacted at a constant temperature of 150°C for 8 hours in a high-pressure reactor. After the reaction was completed, it was naturally cooled to room temperature, the reacted nickel foam was taken out, washed repeatedly with deionized water to remove residual ions on the surface, and then dried in a vacuum oven.
[0065] D. Preparation of hydrogen evolution electrode: Weigh 0.5g of thiourea compound and place it together with the precursor in C into a tube furnace. Under Ar gas atmosphere, heat to 300℃ and hold for about 1 hour. Cool to room temperature to obtain hydrogen evolution electrode.
[0066] Example 3
[0067] A. Pretreatment of nickel foam substrate: First, commercial nickel foam with an area of 3×4cm is ultrasonically cleaned with 1M HCl solution, acetone and water in sequence to remove oxides and organic matter on the surface, and then placed in a vacuum oven to dry.
[0068] B. Preparation of the reaction precursor solution: Weigh 1.7493g of cobalt nitrate, 1.8034g of urea and 0.2220g of ammonium fluoride in sequence and place them in the liner of the reaction vessel. Add 50ml of deionized water and stir magnetically to form a homogeneous solution.
[0069] C. Preparation of the reaction precursor: The pretreated nickel foam was placed in the solution in B and reacted at a constant temperature of 120°C for 10 hours in a high-pressure reactor. After the reaction was completed, it was naturally cooled to room temperature, the reacted nickel foam was removed, washed repeatedly with deionized water to remove residual ions on the surface, and then dried in a vacuum oven.
[0070] D. Preparation of hydrogen evolution electrode: Weigh 0.5g of thiourea and place it together with the precursor in C into a tube furnace. Under Ar gas atmosphere, heat to 400℃ and maintain the temperature for 2h. Cool to room temperature to obtain hydrogen evolution electrode.
[0071] Example 4
[0072] A. Pretreatment of nickel foam substrate: First, commercial nickel foam with an area of 3×4cm is ultrasonically cleaned with 1M HCl solution, acetone and water in sequence to remove oxides and organic matter on the surface, and then placed in a vacuum oven to dry.
[0073] B. Preparation of the reaction precursor solution: Weigh 1.7493g of cobalt nitrate, 2.7047g of urea and 0.2220g of ammonium fluoride in sequence and place them in the liner of the reaction vessel. Add 60ml of deionized water and stir magnetically to form a homogeneous solution.
[0074] C. Preparation of the reaction precursor: The pretreated nickel foam was placed in the solution in B and reacted at a constant temperature of 150℃ for 10 hours in a high-pressure reactor. After the reaction was completed, it was naturally cooled to room temperature, the reacted nickel foam was taken out, washed repeatedly with deionized water to remove residual ions on the surface, and then dried in a vacuum oven.
[0075] D. Preparation of hydrogen evolution electrode: Weigh 1g of thiourea and place it together with the precursor in C into a tube furnace. Under Ar gas atmosphere, heat to 450℃ and hold for 1h. Cool to room temperature to obtain hydrogen evolution electrode.
[0076] Figure 3 The figure shows the hydrogen evolution performance of the hydrogen evolution electrode prepared in Example 4 under different electrolyte conditions. It can be seen from the figure that the catalyst not only has excellent catalytic activity in KOH solution, but also has a small overpotential under alkaline seawater conditions.
[0077] Example 5
[0078] A. Pretreatment of nickel foam substrate: First, commercial nickel foam with an area of 3×4cm is ultrasonically cleaned with 1M HCl solution, acetone and water in sequence to remove oxides and organic matter on the surface, and then placed in a vacuum oven to dry.
[0079] B. Preparation of the reaction precursor solution: Weigh 1.3970g of cobalt nitrate, 1.44g of urea and 0.432g of ammonium fluoride in sequence and place them in the liner of the reaction vessel. Add 60ml of appropriate amount of deionized water and stir magnetically to form a homogeneous solution.
[0080] C. Preparation of the reaction precursor: The pretreated nickel foam was placed in the solution in B and reacted at a constant temperature of 120℃ for 8 hours in a high-pressure reactor. After the reaction was completed, it was naturally cooled to room temperature, the reacted nickel foam was taken out, washed repeatedly with deionized water to remove residual ions on the surface, and then dried in a vacuum oven.
[0081] D. Preparation of hydrogen evolution electrode: Weigh 1g of thiourea and place it together with the precursor in C into a tube furnace. Under the N2 gas atmosphere, heat it to a certain temperature of 450℃ and hold it for 2 hours. Then cool it to room temperature to obtain the hydrogen evolution electrode.
[0082] Figure 2 This is a scanning electron microscope (SEM) image of the hydrogen evolution electrode prepared in Example 5. As can be seen from the image...
[0083] Figure 4 This is a stability graph of the hydrogen evolution electrode prepared in Example 5 under alkaline seawater conditions. The graph shows that the catalyst prepared under these conditions exhibits excellent stability, with no significant decrease in catalytic activity during the 40-hour stability test.
[0084] Example 6
[0085] A. Pretreatment of nickel foam substrate: First, commercial nickel foam with an area of 3×4cm is ultrasonically cleaned with 1M HCl solution, acetone and water in sequence to remove oxides and organic matter on the surface, and then placed in a vacuum oven to dry.
[0086] B. Preparation of the reaction precursor solution: Weigh 1.3970g of cobalt nitrate, 1.44g of urea and 0.222g of ammonium fluoride into the liner of the reaction vessel, add 60ml of deionized water, and stir magnetically to form a homogeneous solution.
[0087] C. Preparation of the reaction precursor: The pretreated nickel foam was placed in the solution in B and reacted at a constant temperature of 120°C for 10 hours in a high-pressure reactor. After the reaction was completed, it was naturally cooled to room temperature, the reacted nickel foam was removed, washed repeatedly with deionized water to remove residual ions on the surface, and then dried in a vacuum oven.
[0088] D. Preparation of hydrogen evolution electrode: Weigh 2g of thiourea and place it together with the precursor in C into a tube furnace. Under N2 atmosphere, heat to 450℃ and hold for 2h. Cool to room temperature to obtain hydrogen evolution electrode.
[0089] Figure 1 The figures show the XRD patterns of the hydrogen evolution electrode and standard card prepared in Example 6. The figures show that the catalyst consists of two types: Ni3S4 and CoS. Figure 3 This is a transmission electron microscope (TEM) image of the catalyst prepared in Example 6. The image shows that the catalyst is composed of two crystals, Ni3S4 and CoS, and is uniformly coated with a layer of nitrogen-doped carbon.
[0090] The above description is merely a few embodiments of this application and is not intended to limit this application in any way. Although this application discloses preferred embodiments as described above, it is not intended to limit this application. Any changes or modifications made by those skilled in the art without departing from the scope of the technical solution of this application using the disclosed technical content are equivalent to equivalent implementation cases and fall within the scope of the technical solution.
Claims
1. A bimetallic hydrogen evolution catalyst, characterized in that, Including Ni3S4 coated with carbonitridium layers and CoS coated with carbonitridium layers; The content of Ni3S4 is 10~20wt%; The content of CoS is 30~40 wt%; The bimetallic hydrogen evolution catalyst comprises two crystalline phases in one crystal lattice. The thickness of the carbon-nitrogen layer is 0.5~1nm.
2. The bimetallic hydrogen evolution catalyst according to claim 1, characterized in that, The bimetallic hydrogen evolution catalyst has a flower-like morphology; The lateral dimensions of the nanosheets are 80~120 nm.
3. A method for preparing the bimetallic hydrogen evolution catalyst according to claim 1 or 2, characterized in that, At least the following steps are included: The raw materials containing nickel source, cobalt source and urea are mixed with water to obtain a mixed solution, reacted, and then mixed with a sulfur source and calcined to obtain the bimetallic hydrogen evolution catalyst. The reaction temperature is 120~150℃; The roasting process includes heating to 300-450°C at a heating rate of 1-5°C / min and holding for 1-2 hours.
4. The preparation method according to claim 3, characterized in that, The nickel source is selected from at least one of nickel foam, nickel nitrate, or nickel chloride; The cobalt source is selected from at least one of cobalt nitrate, cobalt acetate, or cobalt chloride; The sulfur source is selected from at least one of sulfur, thiourea, or thioacetamide; The molar ratio of the nickel source, cobalt source, sulfur source, urea, and water is 1:1:1:2:30 to 1:3:3:5:
50.
5. The preparation method according to claim 3, characterized in that, The raw materials include a buffer; The buffer is selected from at least one of ammonium fluoride, ammonium chloride, or sodium acetate; The pH value of the mixed solution is 6-8.
6. The preparation method according to claim 3, characterized in that, The reaction time is 8-10 hours.
7. The preparation method according to claim 3, characterized in that, The calcination atmosphere is a non-reactive gas atmosphere; The inactive gas is selected from at least one of nitrogen, helium, or argon; The process involves drying before roasting; The drying temperature is 60~80℃; The drying time is 8-12 hours.
8. A hydrogen evolution electrode, characterized in that, Includes the matrix and the catalyst supported on the surface of the matrix; The catalyst is selected from the bimetallic hydrogen evolution catalyst according to claim 1 or 2 or the bimetallic hydrogen evolution catalyst prepared by the preparation method according to any one of claims 3 to 7; The matrix is selected from at least one of nickel foam, copper foam, or carbon paper; In the hydrogen evolution electrode, the catalyst loading is 20~50wt%.
9. A method for preparing the hydrogen evolution electrode according to claim 8, characterized in that, This includes impregnation or coating methods.
10. A method for electrolyzing seawater, characterized in that, Hydrogen evolution electrode prepared by the hydrogen evolution electrode of claim 8 or the preparation method of claim 9; Current density is 100 mA / cm 2 The overpotential is 149mV; Current density is 500 mA / cm 2 The overpotential is 250mV.