Alkaline water electrolysis hydrogen production method and system
By adding nickel and iron salts to an alkaline electrolyte and using the in-situ co-deposition of a nickel-iron catalyst layer during the electrolysis process, the high cost of precious metal catalysts and the complexity of pre-preparation methods in existing alkaline water electrolysis hydrogen production technologies have been solved, realizing a low-cost, high-performance alkaline water electrolysis hydrogen production method.
Patent Information
- Application Number
- CN202511864964.5
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-12-11
- Publication Date
- 2026-03-03
Smart Images
Figure CN121593086A_ABST
Abstract
Description
Technical Field
[0001] This application relates to the field of water electrolysis for hydrogen production technology, and in particular to alkaline water electrolysis methods and systems for hydrogen production. Background Technology
[0002] Alkaline water electrolysis for hydrogen production is one of the most mature and widely used large-scale hydrogen production technologies. However, its high oxygen evolution reaction overpotential and high energy consumption are major bottlenecks restricting the reduction of its operating costs. To reduce the overpotential, highly active catalysts are usually loaded onto the electrodes. Among them, noble metal catalysts have excellent performance but are expensive and difficult to use on a large scale; non-noble metal catalysts (such as nickel-based, iron-based, and cobalt-based catalysts) are the mainstream research direction. In terms of the application of non-noble metal catalysts, the current mainstream technical route relies on "pre-fabricated catalyst electrodes," that is, before the electrolyzer is assembled and operated, a catalyst layer is pre-loaded on the electrode substrate using physical or chemical methods. Traditional methods for preparing catalyst layers loaded on the electrode substrate include slurry coating, electrochemical deposition, and hydrothermal / solvothermal methods.
[0003] Slurry coating requires mixing catalyst powder, conductive agent, and polymer binder to form a slurry before coating. However, the insulating binder increases interfacial resistance and covers active sites, and the catalyst layer is prone to detachment under severe gas evolution conditions, affecting lifespan and electrolyte purity. While electrochemical deposition can directly deposit catalytic films, it requires independent deposition equipment, specialized electrolytes, and precise process control. The process is cumbersome and difficult to achieve large-area uniform deposition, significantly increasing manufacturing costs and complexity. Hydrothermal / solvothermal methods can grow nanostructure arrays on substrates, but they rely on high-temperature and high-pressure reaction conditions, resulting in expensive equipment and huge energy consumption, making large-scale production inherently impractical. The core problem with these prefabrication methods is that they artificially separate electrode fabrication and water electrolysis operation into two independent offline stages. This "prepare first, use later" approach inevitably leads to a series of inherent limitations, including complex processes, high costs, weak adhesion between the catalyst layer and the substrate, and high interfacial impedance. Summary of the Invention
[0004] Therefore, it is necessary to provide a low-cost, high-performance, and easily industrially feasible alkaline water electrolysis method and system for hydrogen production.
[0005] One embodiment of this application provides a method for producing hydrogen by alkaline water electrolysis.
[0006] A method for producing hydrogen by alkaline water electrolysis includes the following steps:
[0007] Add soluble nickel salts and soluble iron salts to the alkaline electrolyte;
[0008] The alkaline electrolyte is injected into the electrolytic cell, and both the anode and cathode of the electrolytic cell are nickel meshes. A composite diaphragm is used to separate the anode chamber and the cathode chamber.
[0009] In addition, the electrolytic cell is controlled to carry out an electrolytic reaction.
[0010] In some embodiments, the alkaline electrolyte comprises a KOH solution or a NaOH solution with a concentration of 25wt% to 35wt%.
[0011] In some embodiments, soluble nickel salts and soluble iron salts are added to the alkaline electrolyte to adjust the Ni content in the alkaline electrolyte. 2+ The initial concentration was 0.5 mM to 10 mM, Fe 3+ The initial concentration is 0.5 mM to 10 mM.
[0012] In some embodiments, the Ni in the alkaline electrolyte is controlled. 2+ with Fe 3+ The molar ratio is 5:(1~25).
[0013] In some embodiments, the Ni in the alkaline electrolyte is controlled. 2+ with Fe 3+ The molar ratio is 2:1 to 1:2.
[0014] In some embodiments, the electrolysis reaction occurs at a current density of 1000 A / m. 2 ~6000 A / m 2 It is carried out under the following conditions.
[0015] In some embodiments, the electrolysis reaction is carried out at a temperature of 45°C to 85°C.
[0016] In some embodiments, the composite membrane comprises a Zirfon-type organic or inorganic composite membrane.
[0017] In some embodiments, the soluble nickel salt includes one or more of nickel sulfate, nickel nitrate, and nickel chloride.
[0018] In some embodiments, the soluble iron salt is one or more of ferric sulfate, ferric nitrate, and ferric chloride.
[0019] One embodiment of this application also provides an alkaline water electrolysis hydrogen production system.
[0020] An alkaline water electrolysis hydrogen production system, comprising:
[0021] Electrolytic cell;
[0022] The electrode includes an anode and a cathode disposed within the electrolytic cell body, wherein both the anode and the cathode are nickel meshes;
[0023] A composite diaphragm is disposed between the anode and the cathode;
[0024] And, an alkaline electrolyte contained in the electrolytic cell;
[0025] In some embodiments, the alkaline electrolyte contains Ni at an initial concentration of 0.5 mM to 10 mM. 2+ Fe with an initial concentration of 0.5 mM to 10 mM 3+ .
[0026] In some embodiments, the Ni in the alkaline electrolyte 2+ with Fe 3+ The molar ratio is 5:(1~25).
[0027] The aforementioned alkaline water electrolysis hydrogen production method is low-cost, high-performance, easy to operate, and readily applicable to industrial applications. This method involves the simultaneous and controlled addition of nickel and iron ions to co-deposit a novel, independent nickel-iron catalyst layer on a nickel substrate through in-situ electrolysis. Furthermore, this application combines electrolyte composition design with a specific diaphragm to ensure the controllability and directionality of the deposition process, and utilizes the visual changes in the electrolyte (from turbidity to clarity) as an indicator for process monitoring.
[0028] In summary, the alkaline water electrolysis hydrogen production method and system of this application have at least the following significant beneficial effects:
[0029] (1) Significantly improved performance: The in-situ formed nickel-iron catalyst layer can significantly improve the electrode reaction kinetics, at 4000 A / m 2 At high current density, a voltage drop of 154mV can be achieved, resulting in significant energy savings.
[0030] (2) Extremely low cost: No complicated electrode prefabrication process is required. Only a small amount of inexpensive metal salt needs to be added to the inexpensive alkaline solution, which greatly reduces the cost of catalyst and manufacturing.
[0031] (3) Simple process and strong compatibility: This method does not require modification of the existing electrolytic cell structure and can be directly implemented in the alkaline water electrolysis system of traditional technology, making it very easy to promote industrialization and upgrade old systems.
[0032] (4) The catalyst layer is strong and stable: the formed catalyst layer is firmly bonded to the nickel mesh substrate. After the system diaphragm is replaced, the performance is still maintained, which proves its long-term operational stability.
[0033] (5) The process is controllable and self-limiting: The phenomenon of the electrolyte changing from turbid to clear directly indicates that the additive ions are completely consumed and deposited on the electrode. The process is controllable and there is no risk of continuous side reactions. Attached Figure Description
[0034] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.
[0035] To gain a more complete understanding of this application and its beneficial effects, the following description will be provided in conjunction with the accompanying drawings. In the following description, the same reference numerals denote the same parts.
[0036] Figure 1 This is a schematic diagram of the alkaline water electrolysis hydrogen production method according to an embodiment of this application;
[0037] Figure 2 This is a comparison graph of the polarization curves of Example 1 and Comparative Example 1;
[0038] Figure 3 This is a comparison diagram of the electrolyte state before and after electrolysis in Example 1;
[0039] Figure 4 This is a comparison of polarization curves before and after replacing the composite diaphragm in Example 1;
[0040] Figure 5 The images shown are SEM and EDS images of the nickel mesh from Example 1. Detailed Implementation
[0041] To make the above-mentioned objectives, features, and advantages of this application more apparent and understandable, the specific embodiments of this application are described in detail below with reference to the accompanying drawings. Many specific details are set forth in the following description to provide a thorough understanding of this application. However, this application can be implemented in many other ways different from those described herein, and those skilled in the art can make similar modifications without departing from the spirit of this application. Therefore, this application is not limited to the specific embodiments disclosed below.
[0042] In the description of this application, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc., indicating the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this application.
[0043] In this application, unless otherwise expressly specified and limited, the terms "installation," "connection," "joining," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components, unless otherwise expressly limited. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.
[0044] In this application, unless otherwise expressly specified and limited, "above" or "below" the second feature can mean that the first feature is in direct contact with the second feature, or that the first feature is in indirect contact with the second feature through an intermediate medium. Furthermore, "above," "on top of," and "over" the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.
[0045] In the description of this application, "several" means one or more, "multiple" means two or more, "greater than," "less than," and "exceeding" are understood to exclude the stated number, while "above," "below," and "within" are understood to include the stated number. The use of "first" and "second" in the description is merely for distinguishing technical features and should not be construed as indicating or implying relative importance, or implicitly indicating the number of indicated technical features, or implicitly indicating the order of the indicated technical features.
[0046] In this document, "optionally," "optionally," and "optional" mean that something is optional, that is, it is selected from either "with" or "without." If multiple "options" appear in a technical solution, unless otherwise specified and there are no contradictions or mutual constraints, each "option" is independent. In this application, descriptions such as "optionally contains" and "optionally includes" indicate "contains or does not contain."
[0047] In this application, unless otherwise stated, the sum of the parts of each component in the composition may be 100 parts by weight. Unless otherwise specified, the percentages (including weight percentages) in this application are based on the total weight of the composition, and "wt%" in this document means mass percentage.
[0048] In this document, unless otherwise stated, the reaction steps may be performed in the order described herein or not. For example, other steps may be included between reaction steps, and the order of reaction steps may be appropriately interchanged. This is something that those skilled in the art can determine based on conventional knowledge and experience. Preferably, the reaction methods described herein are performed sequentially.
[0049] In this application, when numerical intervals (i.e., numerical ranges) are mentioned, unless otherwise specified, the distribution of selectable numerical values within the numerical interval is considered continuous, and includes the two endpoints of the numerical interval (i.e., the minimum and maximum values), as well as every numerical value between these two endpoints. Unless otherwise specified, when a numerical interval refers only to integers within that numerical interval, it includes the two endpoint integers of the numerical range, as well as every integer between the two endpoints, which is equivalent to directly listing every integer. When multiple numerical ranges are provided to describe features or characteristics, these numerical ranges can be merged. In other words, unless otherwise specified, the numerical ranges disclosed in this application should be understood to include any and all subranges included therein. The "numerical value" in the numerical interval can be any quantitative value, such as a number, percentage, ratio, etc. The term "numerical interval" can be broadly included to include percentage intervals, ratio intervals, proportion intervals, etc.
[0050] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the application. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.
[0051] This application provides an alkaline water electrolysis hydrogen production method to address at least one of the following technical problems in the preparation of a catalyst layer loaded on an electrode substrate using conventional techniques: (1) The slurry coating method requires mixing catalyst powder, conductive agent, and polymer binder to form a slurry before coating. However, the insulating binder increases the interfacial resistance and covers the active sites, and the catalyst layer is prone to detachment under severe gas evolution conditions, affecting its lifespan and electrolyte purity. (2) The electrochemical deposition method requires independent deposition equipment, a dedicated electrolyte, and precise process control. The steps are cumbersome and it is difficult to achieve large-area uniform deposition, significantly increasing manufacturing costs and complexity. (3) The hydrothermal / solvothermal method relies on high-temperature and high-pressure reaction conditions, resulting in expensive equipment and huge energy consumption, and is essentially not feasible for large-scale production. The alkaline water electrolysis hydrogen production method will be described below with reference to the accompanying drawings.
[0052] This application provides an embodiment of an alkaline water electrolysis hydrogen production method, which is exemplary. Please refer to [link to relevant documentation]. Figure 1 As shown, Figure 1 This is a schematic diagram of an alkaline water electrolysis hydrogen production method according to an embodiment of this application. The alkaline water electrolysis hydrogen production method of this application can be used in...
[0053] To more clearly illustrate the structure of the alkaline water electrolysis hydrogen production method, the following description, in conjunction with the accompanying drawings, will be provided.
[0054] For example, please refer to Figure 1 As shown, an alkaline water electrolysis method for hydrogen production includes the following steps:
[0055] S10. Add soluble nickel salt and soluble iron salt to the alkaline electrolyte.
[0056] S20. The alkaline electrolyte is injected into the electrolytic cell, and the anode and cathode of the electrolytic cell are both nickel meshes. A composite diaphragm is used to separate the anode chamber and the cathode chamber.
[0057] S30. Control the electrolytic cell to carry out the electrolytic reaction.
[0058] The aforementioned alkaline water electrolysis hydrogen production method is low-cost, high-performance, easy to operate, and readily applicable to industrial applications. This method involves the simultaneous and controlled addition of nickel and iron ions to co-deposit a novel, independent nickel-iron catalyst layer on a nickel substrate through in-situ electrolysis. Furthermore, this application combines electrolyte composition design with a specific diaphragm to ensure the controllability and directionality of the deposition process, and utilizes the visual changes in the electrolyte (from turbidity to clarity) as an indicator for process monitoring.
[0059] In some embodiments, the alkaline electrolyte comprises a KOH solution or a NaOH solution with a concentration of 25wt% to 35wt%. For example, the concentration of the alkaline electrolyte may include, but is not limited to: 25wt%, 27wt%, 28wt%, 30wt%, 31wt%, 32wt%, 33wt%, 34wt%, 35wt%, or any range between the foregoing.
[0060] In some embodiments, soluble nickel salts and soluble iron salts are added to the alkaline electrolyte to adjust the Ni content in the alkaline electrolyte. 2+ The initial concentration was 0.5 mM to 10 mM, Fe 3+ The initial concentration is 0.5 mM to 10 mM. For example, adjusting the Ni concentration in the alkaline electrolyte... 2+ The initial concentration can be, but is not limited to, 0.5 mM, 1 mM, 1.5 mM, 2 mM, 2.5 mM, 3 mM, 3.5 mM, 4 mM, 4.5 mM, 5 mM, 5.5 mM, 6 mM, 6.5 mM, 7 mM, 7.5 mM, 8 mM, 8.5 mM, 9 mM, 9.5 mM, 10 mM, or any range between the foregoing. For example, adjusting the Fe in the alkaline electrolyte... 3+ The initial concentration can be, but is not limited to, 0.5 mM, 1 mM, 1.5 mM, 2 mM, 2.5 mM, 3 mM, 3.5 mM, 4 mM, 4.5 mM, 5 mM, 5.5 mM, 6 mM, 6.5 mM, 7 mM, 7.5 mM, 8 mM, 8.5 mM, 9 mM, 9.5 mM, 10 mM, or any range between the two aforementioned.
[0061] In some embodiments, the Ni in the alkaline electrolyte is controlled. 2+ with Fe 3+ The molar ratio is 5:(1~25). For example, the Ni content in the alkaline electrolyte is controlled. 2+ with Fe 3+ The molar ratio can be, but is not limited to, 5:1, 5:2, 5:3, 5:4, 5:5, 5:6, 5:7, 5:8, 5:8, 5:10, 5:11, 5:12, 5:13, 5:14, 5:15, 5:16, 5:17, 5:18, 5:19, 5:20, 5:21, 5:22, 5:23, 5:24, 5:25, or any range between the two aforementioned.
[0062] In some embodiments, the Ni in the alkaline electrolyte is controlled. 2+ with Fe 3+ The molar ratio is 2:1 to 1:2.
[0063] In some embodiments, the electrolysis reaction occurs at a current density of 1000 A / m. 2 ~6000A / m 2 The electrolysis reaction is carried out under the following conditions. For example, during the electrolysis reaction, the current density may include, but is not limited to, 1000 A / m. 2 2000A / m 2 3000A / m 2 4000A / m 2 5000A / m 2 6000A / m 2 Or the range between any two of the aforementioned.
[0064] In some embodiments, the electrolysis reaction occurs at a temperature of 45°C to 85°C. For example, the electrolysis reaction temperature may be, but is not limited to, 45°C, 50°C, 55°C, 60°C, 65°C, 70°C, 75°C, 80°C, 85°C, or any range between the foregoing.
[0065] In some embodiments, the composite membrane comprises a Zirfon-type organic or inorganic composite membrane.
[0066] In some embodiments, the soluble nickel salt includes one or more of nickel sulfate, nickel nitrate, and nickel chloride.
[0067] In some embodiments, the soluble iron salt is one or more of ferric sulfate, ferric nitrate, and ferric chloride.
[0068] One embodiment of this application also provides an alkaline water electrolysis hydrogen production system.
[0069] An alkaline water electrolysis hydrogen production system, comprising:
[0070] Electrolytic cell;
[0071] The electrode includes an anode and a cathode disposed within the electrolytic cell body, wherein both the anode and the cathode are nickel meshes;
[0072] A composite diaphragm is disposed between the anode and the cathode;
[0073] And, an alkaline electrolyte contained in the electrolytic cell;
[0074] In some embodiments, the alkaline electrolyte contains Ni at an initial concentration of 0.5 mM to 10 mM. 2+ Fe with an initial concentration of 0.5 mM to 10 mM 3+ For example, in an alkaline water electrolysis hydrogen production system, the Ni content in the alkaline electrolyte is adjusted. 2+The initial concentration can be, but is not limited to, 0.5 mM, 1 mM, 1.5 mM, 2 mM, 2.5 mM, 3 mM, 3.5 mM, 4 mM, 4.5 mM, 5 mM, 5.5 mM, 6 mM, 6.5 mM, 7 mM, 7.5 mM, 8 mM, 8.5 mM, 9 mM, 9.5 mM, 10 mM, or any range between the foregoing. For example, adjusting the Fe in the alkaline electrolyte... 3+ The initial concentration can be, but is not limited to, 0.5 mM, 1 mM, 1.5 mM, 2 mM, 2.5 mM, 3 mM, 3.5 mM, 4 mM, 4.5 mM, 5 mM, 5.5 mM, 6 mM, 6.5 mM, 7 mM, 7.5 mM, 8 mM, 8.5 mM, 9 mM, 9.5 mM, 10 mM, or any range between the two aforementioned.
[0075] In some embodiments, in an alkaline water electrolysis hydrogen production system, the Ni in the alkaline electrolyte... 2+ with Fe 3+ The molar ratio is 5:(1~25). For example, in an alkaline water electrolysis hydrogen production system, the Ni content in the alkaline electrolyte is controlled. 2+ with Fe 3+ The molar ratio can be, but is not limited to, 5:1, 5:2, 5:3, 5:4, 5:5, 5:6, 5:7, 5:8, 5:8, 5:10, 5:11, 5:12, 5:13, 5:14, 5:15, 5:16, 5:17, 5:18, 5:19, 5:20, 5:21, 5:22, 5:23, 5:24, 5:25, or any range between the two aforementioned.
[0076] Example 1
[0077] This embodiment provides a method for producing hydrogen by alkaline water electrolysis.
[0078] The alkaline water electrolysis method for producing hydrogen includes the following steps:
[0079] S10. Prepare a 30 wt% KOH solution as an alkaline electrolyte. Add NiSO4·6H2O and Fe2(SO)3 to the alkaline electrolyte to adjust the Ni content. 2+ The initial concentration was 3 mM, Fe 3+ The initial concentration was 1.5 mM. The Ni concentration in the alkaline electrolyte was controlled. 2+ with Fe 3+ The molar ratio is 10:5.
[0080] S20. The alkaline electrolyte is injected into the electrolytic cell. The anode and cathode of the electrolytic cell are both nickel mesh, and the anode chamber and cathode chamber are separated by a YT-500 composite diaphragm.
[0081] S30, at a temperature of 80℃, 4000A / m 2 The electrolyte was electrolyzed at a constant current density for 24 hours. During this period, the electrolyte gradually changed from an initial dark brown turbid state to a light yellow clear state (see [reference]). Figure 3 (As shown).
[0082] Test results: The electrolytic cell voltage steadily decreased from the initial 1.878V to 1.724V, a drop of 154mV. See the SEM and EDS images of the nickel mesh in Example 1. Figure 5 As shown, SEM and EDS characterization revealed that a porous material rich in Ni and Fe was successfully deposited on the surface of the nickel mesh.
[0083] After replacing the YT-500 composite membrane in the alkaline water electrolysis hydrogen production system with a brand new YT-500 composite membrane, the alkaline water electrolysis hydrogen production method was repeated. After testing again, the polarization curve was basically the same as before the replacement. (See [link to relevant documentation]). Figure 2 and Figure 4 As shown, this proves that the performance improvement originates from the electrode itself.
[0084] Example 2
[0085] This embodiment provides a method for producing hydrogen by alkaline water electrolysis.
[0086] The alkaline water electrolysis method for producing hydrogen includes the following steps:
[0087] S10. Prepare a 30 wt% KOH solution as an alkaline electrolyte. Add NiSO4·6H2O and Fe2(SO)3 to the alkaline electrolyte to adjust the Ni content. 2+ The initial concentration was 2 mM, Fe 3+ The initial concentration of Ni is 4 mM. The Ni concentration in the alkaline electrolyte is controlled. 2+ with Fe 3+ The molar ratio is 5:10.
[0088] S20. The alkaline electrolyte is injected into the electrolytic cell. The anode and cathode of the electrolytic cell are both nickel mesh, and the anode chamber and cathode chamber are separated by a YT-500 composite diaphragm.
[0089] S30, at a temperature of 80℃, 4000A / m 2 The electrolyte was electrolyzed at a constant current density for 24 hours. During this period, the electrolyte gradually changed from an initial dark brown turbid state to a light yellow clear state (see [reference]). Figure 3 (As shown).
[0090] Test results: The electrolytic cell voltage steadily decreased from the initial 1.878V to 1.753V, a drop of 125mV. SEM and EDS characterization showed that a porous material rich in Ni and Fe was successfully deposited on the nickel mesh surface.
[0091] Example 3
[0092] This embodiment provides a method for producing hydrogen by alkaline water electrolysis.
[0093] The alkaline water electrolysis method for producing hydrogen includes the following steps:
[0094] S10. Prepare a 30 wt% KOH solution as an alkaline electrolyte. Add NiSO4·6H2O and Fe2(SO)3 to the alkaline electrolyte to adjust the Ni content. 2+ The initial concentration was 5 mM, Fe 3+ The initial concentration of Ni is 1 mM. The Ni concentration in the alkaline electrolyte is controlled. 2+ with Fe 3+ The molar ratio is 5:1.
[0095] S20. The alkaline electrolyte is injected into the electrolytic cell. The anode and cathode of the electrolytic cell are both nickel mesh, and the anode chamber and cathode chamber are separated by a YT-500 composite diaphragm.
[0096] S30, at a temperature of 80℃, 4000A / m 2 The electrolyte was electrolyzed at a constant current density for 24 hours. During this period, the electrolyte gradually changed from an initial dark brown turbid state to a light yellow clear state (see [reference]). Figure 3 (As shown).
[0097] Test results: The electrolytic cell voltage steadily decreased from the initial 1.878V to 1.766V, a drop of 112mV. SEM and EDS characterization showed that a porous material rich in Ni and Fe was successfully deposited on the nickel mesh surface.
[0098] Example 4
[0099] This embodiment provides a method for producing hydrogen by alkaline water electrolysis.
[0100] The alkaline water electrolysis method for producing hydrogen includes the following steps:
[0101] S10. Prepare a 30wt% KOH solution as an alkaline electrolyte. Add NiSO4·6H2O and Fe2(SO3)3 to the alkaline electrolyte to adjust the Ni content. 2+ The initial concentration was 1.5 mM, Fe 3+ The initial concentration was 4.5 mM. The Ni concentration in the alkaline electrolyte was controlled. 2+with Fe 3+ The molar ratio is 5:15.
[0102] S20. The alkaline electrolyte is injected into the electrolytic cell. The anode and cathode of the electrolytic cell are both nickel mesh, and the anode chamber and cathode chamber are separated by a YT-500 composite diaphragm.
[0103] S30, at a temperature of 80℃, 4000A / m 2 The electrolyte was electrolyzed at a constant current density for 24 hours. During this period, the electrolyte gradually changed from an initial dark brown turbid state to a light yellow clear state (see [reference]). Figure 3 (As shown).
[0104] Test results: The electrolytic cell voltage steadily decreased from the initial 1.878V to 1.773V, a drop of 105mV. SEM and EDS characterization showed that a porous material rich in Ni and Fe was successfully deposited on the nickel mesh surface.
[0105] Comparative Example 1
[0106] This comparative example provides a method for producing hydrogen by alkaline water electrolysis.
[0107] The alkaline water electrolysis method for hydrogen production in this comparative example is basically the same as that in Example 1, except that no nickel-iron salt is added to the alkaline electrolyte of 30wt% KOH.
[0108] At 4000A / m 2 The electrolytic reaction was carried out under constant current at a certain current density for 24 hours. The voltage of the electrolytic cell stabilized at around 1.878V, with no significant decrease.
[0109] Comparative Example 2
[0110] This comparative example provides a method for producing hydrogen by alkaline water electrolysis.
[0111] The alkaline water electrolysis method for hydrogen production in this comparative example is basically the same as that in Example 2, except that the concentration of the alkaline electrolyte is 20 wt%, which is a smaller concentration.
[0112] Test results: The electrolytic cell voltage dropped steadily from the initial 1.878V to 1.794V, a decrease of 84mV.
[0113] Comparative Example 3
[0114] This comparative example provides a method for producing hydrogen by alkaline water electrolysis.
[0115] The alkaline water electrolysis method for hydrogen production in this comparative example is basically the same as that in Example 2, except that the concentration of the alkaline electrolyte is 40 wt%, which is a relatively high concentration.
[0116] Test results: The electrolytic cell voltage dropped steadily from the initial 1.878V to 1.779V, a decrease of 99mV.
[0117] Comparative Example 4
[0118] This comparative example provides a method for producing hydrogen by alkaline water electrolysis.
[0119] The alkaline water electrolysis method for producing hydrogen in this comparative example is basically the same as that in Example 3, except that the electrolysis temperature of the alkaline electrolyte is controlled at 40°C, which is a lower electrolysis temperature.
[0120] Test results: The electrolytic cell voltage dropped steadily from the initial 1.878V to 1.811V, a decrease of 67mV.
[0121] Comparative Example 5
[0122] This comparative example provides a method for producing hydrogen by alkaline water electrolysis.
[0123] The alkaline water electrolysis method for producing hydrogen in this comparative example is basically the same as that in Example 3, except that the electrolysis temperature of the alkaline electrolyte is controlled at 90°C, which is a relatively high electrolysis temperature.
[0124] Test results: The electrolytic cell voltage dropped steadily from the initial 1.878V to 1.798V, a decrease of 80mV.
[0125] Comparative Example 6
[0126] This comparative example provides a method for producing hydrogen by alkaline water electrolysis.
[0127] The alkaline water electrolysis method for hydrogen production in this comparative example is basically the same as that in Example 3, except that the Fe content in the alkaline electrolyte is controlled. 3+ The initial concentration was 1 mM, which is the Fe in the alkaline electrolyte. 3+ The concentration is too low.
[0128] Test results: The electrolytic cell voltage dropped steadily from the initial 1.878V to 1.832V, a decrease of 46mV.
[0129] Comparative Example 7
[0130] This comparative example provides a method for producing hydrogen by alkaline water electrolysis.
[0131] The alkaline water electrolysis method for hydrogen production in this comparative example is basically the same as that in Example 4, except that the Fe content in the alkaline electrolyte is controlled. 3+ The initial concentration was 9 mM, which is the Fe concentration in the alkaline electrolyte. 3+ The concentration is too high.
[0132] Test results: The electrolytic cell voltage dropped steadily from the initial 1.878V to 1.819V, a decrease of 59mV.
[0133] The results show that when Ni 2+ Concentrations of Fe in the range of 1 mM to 5 mM 3+ When the concentration is between 1 mM and 5 mM and the molar ratio is between 2:1 and 1:2, a significant voltage drop effect (70 mV to 160 mV) can be observed. Among them, the ratio of Example 1 has the best effect.
[0134] This application abandons the complex process of traditional pre-prepared catalysts and creatively proposes a method for achieving electrode self-catalysis during electrolytic cell operation. The core lies in the active and simultaneous introduction of nickel and iron ions into the alkaline electrolyte. Utilizing the electric field and chemical environment of the electrolysis process itself, these ions are guided to undergo in-situ electrochemical co-deposition on the surface of an inexpensive pure nickel mesh electrode, dynamically constructing a highly active nickel-iron catalytic layer, thereby significantly reducing the overpotential of the oxygen evolution reaction. Specifically, this application specifies the use of a composite diaphragm to prevent ion cross-contamination, ensuring the directionality and efficiency of deposition; simultaneously, the visual change of the alkaline electrolyte from turbid to clear during deposition provides an intuitive endpoint indication for this self-limiting process.
[0135] In summary, the alkaline water electrolysis hydrogen production method and system of this application have at least the following significant beneficial effects:
[0136] (1) Significantly improved performance: The in-situ formed nickel-iron catalyst layer can significantly improve the electrode reaction kinetics, at 4000 A / m 2 At high current density, a voltage drop of approximately 154mV can be achieved, resulting in significant energy savings.
[0137] (2) Extremely low cost: No complicated electrode prefabrication process is required. Only a small amount of inexpensive metal salt needs to be added to the inexpensive alkaline solution, which greatly reduces the cost of catalyst and manufacturing.
[0138] (3) Simple process and strong compatibility: This method does not require modification of the existing electrolytic cell structure and can be directly implemented in the alkaline water electrolysis system of traditional technology, making it very easy to promote industrialization and upgrade old systems.
[0139] (4) The catalyst layer is strong and stable: the formed catalyst layer is firmly bonded to the nickel mesh substrate. After the system diaphragm is replaced, the performance is still maintained, which proves its long-term operational stability.
[0140] (5) The process is controllable and self-limiting: The phenomenon of the electrolyte changing from turbid to clear directly indicates that the additive ions are completely consumed and deposited on the electrode. The process is controllable and there is no risk of continuous side reactions.
[0141] In the above embodiments, the descriptions of each embodiment have different focuses. For parts not described in detail in a certain embodiment, please refer to the relevant descriptions in other embodiments.
[0142] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.
[0143] The embodiments described above are merely illustrative of several implementation methods of this application, and while the descriptions are specific and detailed, they should not be construed as limiting the scope of this patent application. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the protection scope of this application. Therefore, the protection scope of this patent application should be determined by the appended claims.
Claims
1. A method for producing hydrogen by alkaline water electrolysis, characterized in that, Includes the following steps: Add soluble nickel salts and soluble iron salts to the alkaline electrolyte; The alkaline electrolyte is injected into the electrolytic cell, and both the anode and cathode of the electrolytic cell are nickel meshes. A composite diaphragm is used to separate the anode chamber and the cathode chamber. In addition, the electrolytic cell is controlled to carry out an electrolytic reaction.
2. The alkaline water electrolysis hydrogen production method according to claim 1, characterized in that, The alkaline electrolyte includes a KOH solution or a NaOH solution with a concentration of 25wt% to 35wt%.
3. The alkaline water electrolysis hydrogen production method according to claim 1, characterized in that, Soluble nickel and soluble iron salts are added to the alkaline electrolyte to adjust the Ni content in the alkaline electrolyte. 2+ The initial concentration was 0.5 mM to 10 mM, Fe 3+ The initial concentration is 0.5 mM to 10 mM.
4. The alkaline water electrolysis method for hydrogen production according to claim 1, characterized in that, Controlling the Ni in the alkaline electrolyte 2+ with Fe 3+ The molar ratio is 5:(1~25).
5. The alkaline water electrolysis method for hydrogen production according to claim 4, characterized in that, Controlling the Ni in the alkaline electrolyte 2+ with Fe 3+ The molar ratio is 2:1 to 1:
2.
6. The alkaline water electrolysis method for hydrogen production according to claim 1, characterized in that, During the electrolysis reaction, the current density is 1000 A / m 2 ~6000A / m 2 Under the conditions; And / or, during the electrolysis reaction, the reaction temperature is 45℃~85℃.
7. The alkaline water electrolysis method for hydrogen production according to any one of claims 1 to 6, characterized in that, The composite membrane includes a Zirfon-type organic or inorganic composite membrane.
8. The alkaline water electrolysis method for hydrogen production according to any one of claims 1 to 6, characterized in that, The soluble nickel salt includes one or more of nickel sulfate, nickel nitrate, and nickel chloride.
9. The alkaline water electrolysis method for hydrogen production according to any one of claims 1 to 6, characterized in that, The soluble iron salt is one or more of ferric sulfate, ferric nitrate, and ferric chloride.
10. An alkaline water electrolysis hydrogen production system, characterized in that, include: Electrolytic cell; The electrode includes an anode and a cathode disposed within the electrolytic cell body, wherein both the anode and the cathode are nickel meshes; A composite diaphragm is disposed between the anode and the cathode; And, an alkaline electrolyte contained in the electrolytic cell; Optionally, the alkaline electrolyte contains Ni at an initial concentration of 0.5 mM to 10 mM. 2+ Fe with an initial concentration of 0.5 mM to 10 mM 3+ ; Optionally, the Ni in the alkaline electrolyte 2+ with Fe 3+ The molar ratio is 5:(1~25).