Extraction-assisted membrane-free water electrolysis hydrogen production method and device

Abstract

The invention belongs to the field of hydrogen energy preparation, and particularly discloses an extraction-assisted membrane-free water electrolysis hydrogen production method and device.The extraction-assisted membrane-free water electrolysis hydrogen production method comprises the steps that S1, electrolyte is injected into a membrane-free electrolytic bath, S2, electrolytic hydrogen production is executed, S3, hydrogen separated out of a hydrogen evolution electrode is collected, electrolysis voltage is monitored, hydrogen production is interrupted when the rising amplitude exceeds a set value, and if the rising amplitude exceeds the set value, hydrogen production is stopped; s4, injecting the organic liquid phase into the electrolyte to promote the organic liquid phase to extract the bromine / iodine elementary substance, and then recovering all the organic liquid phase and part of the electrolyte into the first container, S5, restarting the external power supply to restart electrolytic hydrogen production, adding ascorbic acid into the first container to reduce the bromine / iodine elementary substance, and obtaining dehydroascorbic acid at the same time, and S6, while continuous electrolytic hydrogen production is performed, the electrolyte in the first container flows back to the electrolytic bath again. The invention also provides a device for realizing the method. The method provided by the invention solves the problems of insufficient continuous circularity and insufficient hydrogen production efficiency of a membrane-free water electrolysis hydrogen production process in the prior art.

Description

Technical Field

[0001] This application belongs to the field of hydrogen energy production, and more specifically, relates to an extraction-assisted membraneless electrolysis method and apparatus for hydrogen production. Background Technology

[0002] Traditional water electrolysis technology is widely used in green hydrogen production, but it also faces several key bottlenecks. For example, the slow kinetics of the anode OER (Oxygen Evolution) process lead to high overpotentials, significantly limiting electrolysis efficiency. Even with non-precious metal catalysts in alkaline water electrolysis, the overpotential typically exceeds 200mV. Simultaneously, hydrogen evolution at the cathode and oxygen evolution at the anode occur simultaneously, relying solely on a membrane for physical separation. This can easily lead to cross-permeation of hydrogen and oxygen, posing an explosion risk. Furthermore, maintaining the transmembrane pressure difference during high-voltage operation increases resistance and further reduces efficiency. More critically, traditional electrolyzers lack inherent charge storage capacity, have poor adaptability to power fluctuations from renewable energy sources such as solar and wind power, and are prone to accelerated equipment degradation under low-load operation, requiring additional battery-assisted stabilization systems.

[0003] To address this issue, decoupled water electrolysis technology has emerged, achieving spatiotemporal separation of the hydrogen and oxygen reactions by introducing a redox medium, exhibiting multiple significant advantages. In terms of efficiency and energy consumption, its innovative stepwise reaction mechanism can significantly reduce overpotential. For example, patent application CN 114561652 discloses a stepwise oxygen evolution mechanism based on nickel hydroxide oxidation-reduction, achieving decoupling of water electrolysis and reducing potential. Patent application 202510924427.9 proposes a membrane-free water electrolysis hydrogen production system, where hydrogen and oxygen can be generated at different times and in different devices, fundamentally avoiding the risk of gas mixing. It can even operate safely in a membrane-free electrolyzer. Simultaneously, its built-in charge storage capacity can buffer power fluctuations, adapting to complex operating conditions such as low light and light winds. It can respond to load changes in renewable energy without additional battery assistance, significantly improving safety and flexibility.

[0004] However, it cannot be repeated, and its efficiency and practical engineering applicability are lacking. Therefore, it is necessary to develop a device and method that eliminates the traditional membrane electrode and achieves efficient hydrogen production through cyclic decoupled water electrolysis. Summary of the Invention

[0005] In view of the shortcomings of the prior art, the purpose of this application is to provide an extraction-assisted membraneless electrolysis water production method and apparatus, which aims to solve the problems of insufficient continuous circulation and insufficient hydrogen production efficiency in the existing membraneless electrolysis water production process.

[0006] To achieve the above objectives, in a first aspect, this application provides an extraction-assisted membrane-free water electrolysis method for hydrogen production, comprising the following steps: S1: Inject the electrolyte containing bromide ions and / or iodide ions into a membrane-free electrolytic cell, which is equipped with a hydrogen evolution electrode and a bromine / iodine evolution electrode. Remove the air from the membrane-free electrolytic cell and connect the hydrogen electrode and the bromine / iodine evolution electrode to an external power source. S2: Stir the electrolyte, turn on the external power supply, and perform electrolytic hydrogen production. Bromine / iodine elements are generated at the bromine / iodine electrode. S3: Collect the hydrogen gas evolved on the hydrogen evolution electrode, monitor the electrolysis voltage, and when the voltage rises above a set value, turn off the external power supply to interrupt the electrolytic hydrogen production. S4: Inject the organic liquid phase into the electrolyte containing bromine / iodine, and stir continuously to promote the extraction of bromine / iodine by the organic liquid phase. Once the electrolyte returns to a colorless and clear state, recover all the organic liquid phase and part of the electrolyte together into the first container. S5: Restart the external power supply to restart the electrolytic hydrogen production. Simultaneously, stir the liquid in the first container and add ascorbic acid to the first container to reduce bromine / iodine, thereby obtaining dehydroascorbic acid. S6: While continuously producing hydrogen by electrolysis, the electrolyte in the first container is returned to the electrolytic cell to replenish bromide ions and / or iodide ions, thereby ensuring the continuity of hydrogen production by electrolysis. Dehydroascorbic acid is also introduced, which is used to reduce the electrolysis potential and thus improve the electrolysis efficiency.

[0007] In the above-mentioned inventive concept, after bromide ions and / or iodide ions are converted into elemental bromine and / or iodine during the electrolytic hydrogen production process, the raw materials for hydrogen production in the electrolyte are gradually consumed. When all of them are consumed, electrolysis cannot continue. Injecting an organic liquid phase into the electrolyte extracts elemental bromine and / or iodine, and then using ascorbic acid to convert the elemental bromine and / or iodine back into bromide ions and / or iodide ions ensures that the raw materials for hydrogen production are replenished. This cycle allows for a continuous supply of raw materials for hydrogen production, ultimately enabling sustainable and repeated hydrogen production, significantly improving the efficiency of hydrogen production. Furthermore, the conversion of ascorbic acid to dehydroascorbic acid lowers the electrolysis potential for subsequent hydrogen production, improving efficiency. This is because, on the one hand, it reduces the cell voltage; the redox potential of ascorbic acid / dehydroascorbic acid is much lower than that of the bromine evolution reaction, and the anode may experience a direct electro-oxidation reaction of ascorbic acid as an auxiliary process, thereby lowering the electrolysis potential. On the other hand, it can suppress side reactions and corrosion. During the extraction and reduction process, even if a small amount of ascorbic acid is not involved in the reaction and is carried to the electrolyzer, the ascorbic acid can react with the generated bromine during the electrolysis process to reduce the accumulation of bromine, thereby reducing the impact of bromine on electrode corrosion and hydrogen production efficiency.

[0008] Furthermore, steps S3 to S6 are repeated sequentially to cyclically produce hydrogen through electrolysis, thereby improving the efficiency of hydrogen production per unit time.

[0009] Furthermore, the electrolyte for bromide ions and / or iodide ions is a sodium bromide electrolyte, a sodium iodide electrolyte, or a mixture of both.

[0010] Furthermore, the organic liquid phase is one or a mixture of several of ethyl benzoate, n-hexane, benzene, and butyl ether. Ethyl benzoate has a density of approximately 1.05 g / cm³. 3 Slightly larger than water, almost insoluble in water, and weakly polar, it forms a stratified layer with water and usually sinks to the bottom. The density of n-hexane is approximately 0.66 g / cm³. 3 It is much smaller than water, insoluble in water, and forms a distinct stratification with water, floating on top of the water layer. Benzene has a density of approximately 0.88 g / cm³. 3 It has a density less than water, is slightly soluble in water, and has very weak polarity. It forms a stratified layer with water and floats on top. The density of butyl ether is approximately 0.77 g / cm³. 3 It has a density less than water, is slightly soluble in water, forms a stratified layer with water, and floats on top of the water.

[0011] Furthermore, in step S4, the organic liquid phase is injected into the electrolyte containing bromine / iodine. The injected organic liquid phase and the aqueous electrolyte phase are separated into layers, with the organic liquid phase layer thickness being 2 cm to 10 cm. When the density of the organic liquid phase is greater than that of the electrolyte, the organic liquid phase is below the aqueous electrolyte layer, and vice versa. Regardless of whether the organic liquid phase is above or below, in a membrane-free electrolytic cell, a layer thickness of 2 cm to 10 cm for the organic liquid phase is sufficient, while the layer thickness of the aqueous electrolyte layer is equal to the original electrolyte volume, which is much greater than the thickness of the organic liquid phase.

[0012] Furthermore, all the organic liquid phase and part of the electrolyte are recycled together into the first container, with the volume ratio of organic liquid phase to electrolyte being 2:1 to 5:1. At this time, the mixed liquid contains some electrolyte in an aqueous phase, which facilitates the subsequent dissolution of bromide ions and / or iodide ions, and can also dissolve the added ascorbic acid. When the electrolyte is subsequently returned from the first container to the electrolytic cell, the electrolyte is rich in bromide ions and / or iodide ions, and is also rich in dehydroascorbic acid.

[0013] Furthermore, in step S3, the electrolysis voltage is monitored, and when its rise exceeds 20% of the initial electrolysis voltage and the electrolysis potential curve shows an inflection point, the external power supply is turned off to interrupt the electrolysis hydrogen production.

[0014] Furthermore, all stirring speeds were maintained between 120 r / min and 180 r / min.

[0015] According to a second aspect of the present invention, an apparatus for realizing the extraction-assisted membraneless electrolysis of water to produce hydrogen as described above includes a membraneless single tank, a hydrogen evolution electrode, a bromine / iodine evolution electrode, a magnetic stirring unit, a first container, and a peristaltic pump. The membraneless single tank is a covered box for containing the electrolyte. The hydrogen evolution electrode and the bromine / iodine evolution electrode are disposed in the membraneless single tank and immersed in the electrolyte. The magnetic stirring unit is disposed in the electrolyte to stir it. The peristaltic pump connects the membraneless single tank and the first container. The top cover of the membraneless single tank is provided with a hydrogen outlet and an organic liquid phase inlet / outlet.

[0016] Overall, the technical solutions conceived in this application have the following beneficial effects compared with the prior art: (1) In the method of the present invention, the bromine precipitated after electrolysis is transferred to an organic tank by organic phase extraction and reduced by ascorbic acid in the organic tank. The reduced bromide ions are returned to the electrolytic cell for the next electrolysis. This process of bromide ions participating in the secondary electrolysis realizes the recycling of raw materials and also realizes the recycling of hydrogen. The addition of ascorbic acid to reduce the bromine precipitated after electrolysis to obtain bromide ions realizes the recycling of bromide ions. Moreover, the ascorbic acid is oxidized by elemental bromine to obtain dehydroascorbic acid. The dehydroascorbic acid enters the electrolytic cell as a buffer, which helps to reduce the reaction potential and improves the efficiency of electrolytic hydrogen production. The extraction-assisted membraneless electrolysis method for hydrogen production of the present invention has multiple benefits. It realizes the recycling of bromine, making continuous cyclic hydrogen production possible. It also reduces the potential of the secondary electrolysis and all subsequent electrolysis, which can improve the efficiency of electrolytic hydrogen production.

[0017] (2) This application only produces hydrogen and no oxygen, which fundamentally solves the problem of hydrogen-oxygen mixing and ensures the purity of hydrogen.

[0018] (3) The device of this application does not require membrane components or expensive oxygen evolution catalysts, which can reduce costs and improve efficiency compared with traditional electrolysis hydrogen production. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of the extraction-assisted membrane-free water electrolysis hydrogen production method provided in the embodiments of this application; Figure 2 This is a schematic diagram of the apparatus for the extraction-assisted membraneless electrolysis of water to produce hydrogen provided in the embodiments of this application.

[0020] Figure 3 This is a potential window diagram of multiple rounds of electrochemical reactions provided in Example 1 of this application.

[0021] Figure 4 This is a comparison chart showing the effect of adding or not adding dehydroascorbic acid on the electrolysis reaction, provided in Example 2 of this application.

[0022] In all the accompanying drawings, the same reference numerals are used to denote the same elements or structures, wherein: 1-Membrane-free single tank; 2-Hydrogen evolution electrode; 3-Bromine / iodine evolution electrode; 4-Hydrogen collection port; 5-Organic liquid phase inlet and outlet; 6-First container; 7-Organic liquid phase; 8-Electrolyte; 9-Magnetic stirring unit; 10-Peristaltic pump. Detailed Implementation

[0023] To make the objectives, technical solutions, and advantages of this application clearer, the following detailed description is provided in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the scope of this application.

[0024] The embodiments of the present invention are implemented under the premise of the technical solution of the present invention, and detailed implementation methods and processes are given. However, the protection scope of the present invention is not limited to the following embodiments. The process parameters in the following embodiments that do not specify specific conditions are generally in accordance with conventional conditions.

[0025] In this article, the term "and / or" describes the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, or B existing alone. The symbol " / " in this article indicates that the related objects are in an "or" relationship; for example, A / B means A or B.

[0026] The terms "first" and "second," etc., used in the specification and claims herein are used to distinguish different objects, not to describe a specific order of objects. For example, "first response message" and "second response message," etc., are used to distinguish different response messages, not to describe a specific order of response messages.

[0027] In the embodiments of this application, the terms "exemplary" or "for example" are used to indicate that something is an example, illustration, or description. Any embodiment or design that is described as "exemplary" or "for example" in the embodiments of this application should not be construed as being more preferred or advantageous than other embodiments or design. Specifically, the use of the terms "exemplary" or "for example" is intended to present the relevant concepts in a specific manner.

[0028] In the description of the embodiments in this application, unless otherwise stated, "multiple" means two or more, for example, multiple processing units means two or more processing units, and multiple elements means two or more elements. Process parameters in the following embodiments that do not specify specific conditions are generally based on conventional conditions.

[0029] Figure 1This is a schematic diagram of the extraction-assisted membrane-free water electrolysis hydrogen production method provided in the embodiments of this application. As shown in the figure, the core and key steps are as follows: S1: Inject the electrolyte containing bromide ions and / or iodide ions into a membrane-free electrolytic cell. The membrane-free electrolytic cell is equipped with a hydrogen evolution electrode and a bromine / iodide evolution electrode. Air is removed from the membrane-free electrolytic cell, and an external power source is connected between the hydrogen electrode and the bromine / iodide evolution electrode. The electrolyte containing bromide ions and / or iodide ions is a sodium bromide electrolyte, a sodium iodide electrolyte, or a mixture of both. The voltage of the external power source is determined according to the electrolysis requirements and shall not be less than 1.5V.

[0030] S2: Stir the electrolyte at a speed of 120 r / min to 180 r / min, turn on the external power supply, and perform electrolytic hydrogen production. Bromine / iodine elements are generated at the bromine / iodine electrode. S3: Collect the hydrogen gas evolved on the hydrogen evolution electrode, monitor the electrolysis voltage, and when its rise exceeds a set value, shut off the external power supply to interrupt the electrolytic hydrogen production. Specifically, monitor the electrolysis voltage, and when its rise exceeds 20% of the initial electrolysis voltage and the electrolysis potential curve shows an inflection point, shut off the external power supply to interrupt the electrolytic hydrogen production.

[0031] S4: Inject the organic liquid phase into the electrolyte containing bromine / iodine. The injected organic liquid phase and the aqueous electrolyte phase will separate into layers, with the organic liquid phase layer thickness being 2 cm to 10 cm. Continuously stir at a speed of 120 r / min to 180 r / min to promote the extraction of bromine / iodine by the organic liquid phase. When the electrolyte returns to a colorless and clear state, and the organic liquid phase darkens in color, it indicates that the bromine / iodine has been completely extracted by the organic liquid phase. Collect all the organic liquid phase and a portion of the electrolyte together into the first container. The volume ratio of organic liquid phase to electrolyte is 2:1 to 5:1. The organic liquid phase is one or a mixture of several of ethyl benzoate, n-hexane, benzene, and butyl ether. S5: Restart the external power supply to restart the electrolytic hydrogen production. Simultaneously, stir the liquid in the first container at a speed of 120 r / min to 180 r / min. Add ascorbic acid to the first container to reduce bromine / iodine, thereby obtaining dehydroascorbic acid. Bromine / iodine is converted into bromide ions / iodide ions. The solubility of bromide ions / iodide ions in the electrolyte is much greater than their solubility in the organic liquid phase. Similarly, the solubility of dehydroascorbic acid in the electrolyte is also much greater than its solubility in the organic liquid phase. At this point, the electrolyte in the first container is rich in bromide ions / iodide ions and dehydroascorbic acid.

[0032] S6: While continuously producing hydrogen by electrolysis, the electrolyte rich in bromide / iodide ions and dehydroascorbic acid in the first container is refluxed back into the electrolytic cell to replenish bromide ions and / or iodide ions in the electrolyte, thereby ensuring the continuity of hydrogen production by electrolysis. Dehydroascorbic acid is also introduced in this process, which is used to reduce the electrolysis potential and thus improve the electrolysis efficiency.

[0033] Steps S3 to S6 are repeated sequentially to cyclically produce hydrogen through electrolysis, thereby improving the efficiency of hydrogen production per unit time.

[0034] In fact, when the electrolysis potential suddenly becomes too high, that is, when its rise exceeds 20% of the initial electrolysis voltage and the electrolysis potential curve shows an inflection point, it indicates that the bromine / iodide ion content in the electrolyte is low, which may affect the hydrogen evolution efficiency. In this case, the bromine / iodide ions should be replenished through an extraction step.

[0035] Figure 2 This is a schematic diagram of the extraction-assisted membraneless electrolysis water production hydrogen production method apparatus provided in this application embodiment. As shown in the figure, it includes a membraneless single tank 1, a hydrogen evolution electrode 2, a bromine / iodine evolution electrode 3, a magnetic stirring unit 9, a first container 6, and a peristaltic pump 10. The membraneless single tank 1 is a covered box used to contain the electrolyte 8 and the organic liquid phase 7. The hydrogen evolution electrode 2 and the bromine / iodine evolution electrode 3 are disposed in the membraneless single tank 1 and immersed in the electrolyte 8. The magnetic stirring unit 9 is disposed in the electrolyte 8 to stir the electrolyte. The peristaltic pump 10 connects the membraneless single tank 1 and the first container 6. The top cover of the membraneless single tank is provided with a hydrogen outlet 4 and an organic liquid phase inlet and outlet 5, which can also be used to add ascorbic acid.

[0036] The first container 6 can be a storage tank, and the magnetic stirring unit 9 can be a magnetic stirrer that stirs under magnetic force at a speed of 120 r / min to 180 r / min. Depending on the density of the specific organic liquid phase, a reflux opening for the organic liquid phase can be installed on the upper or lower part of the membrane-free single tank. This reflux opening is connected to the first container 6 to allow the electrolyte in the first container to flow back into the electrolytic cell. Alternatively, a magnetic stirring unit 9 can also be installed in the first container for stirring within it.

[0037] The method of the present invention will be further described in detail below with reference to specific embodiments. Example 1 This embodiment provides an extraction-assisted membraneless electrolysis method for hydrogen production. The method is carried out in stages sequentially within a membraneless electrolyzer, which is a box-type covered container. Specifically, the method includes: S1: A near-neutral electrolyte is injected into a membrane-free electrolytic cell, which is equipped with a hydrogen evolution electrode, a bromine evolution electrode, and a magnetic stirring unit. The electrolyte is a 1.5 M sodium bromide solution with a pH of 6.5.

[0038] S2: Expel the air from the membraneless electrolytic cell, stir the electrolyte, and turn on the power.

[0039] S3: Start the electrolytic hydrogen production, collect the H2 evolved on the hydrogen evolution electrode, monitor the electrolysis voltage, and when its rise exceeds 20% of the initial electrolysis voltage and the electrolysis potential curve shows an inflection point, turn off the external power supply to interrupt the electrolytic hydrogen production.

[0040] S4: An organic liquid phase, ethyl benzoate, is drawn from the first container and introduced into the electrolytic cell. The electrolyte is stirred at low speed and allowed to stand. The height of the organic liquid phase introduced into the electrolytic cell is 2 cm. Stirring is continued, with the magnetic stirring unit rotating at 120 r / min. After the aqueous phase in the electrolyte becomes noticeably lighter in color, the mixture of the organic and aqueous phases drawn from the electrolytic cell is returned to the first container via a peristaltic pump. The volume ratio of the organic liquid phase to the electrolyte is 2:1.

[0041] S5: Restart the power supply to continue electrolyzing hydrogen and collecting hydrogen gas. At the same time, slowly add a certain amount of ascorbic acid to the organic tank, stir at low speed until the color in the organic phase fades, then stop adding and let it stand.

[0042] S6: While continuously producing hydrogen through electrolysis, the electrolyte rich in bromide ions and dehydroascorbic acid in the first container is returned to the electrolytic cell.

[0043] S7: Repeat steps S3-S4 for the next round of preparation.

[0044] The concentration of bromine, the yield of hydrogen, and the purity of hydrogen in the electrolyte were tested before and after each round of electrolysis (in the table, "before electrolysis" indicates extraction and reduction followed by "electrolysis"). Specific data are shown in Table 1 below. Voltage changes and hydrogen generation during multiple cycles of hydrogen production are also shown below. Figure 3 As shown, Figure 3 The potential window diagram of the multiple rounds of electrochemical reaction provided in Example 1 of this application shows that the voltage is relatively stable during the multiple rounds of cyclic reaction and the durability does not decrease significantly.

[0045] Table 1. Bromine concentration before and after each round of electrolysis.

[0046] In the table above, the first round indicates the first start of electrolytic hydrogen production, the second round indicates the restart of electrolytic hydrogen production after one extraction and ascorbic acid reduction of bromine, followed by the return of the electrolyte to the electrolytic cell, and the second and third rounds follow the same pattern.

[0047] As shown in Table 1 above, the extraction-assisted membrane-free water electrolysis hydrogen production method provided in this application can collect high-purity hydrogen gas, with a purity of over 99%. Furthermore, the extraction-reduction method effectively reduces the concentration of elemental bromine electrolyzed, providing conditions for subsequent cyclic hydrogen production. The stable voltage values ​​across multiple cycles demonstrate the process stability.

[0048] Example 2 To verify the effect of reduced dehydroascorbic acid on electrolysis, this example adds 0.2M dehydroascorbic acid to the electrolyte solution of Example 1 (containing 1.5 M sodium bromide), and tests its lsv. The results are as follows. Figure 4 As shown, Figure 4 This is a comparison chart of the effects of adding or not adding dehydroascorbic acid on the electrolysis reaction provided in Example 2 of this application. As can be seen from the chart, adding dehydroascorbic acid has a promoting effect on the electrolysis reaction and acts as a buffer to reduce the reaction cell potential.

[0049] Example 3 S1: Sodium iodide electrolyte is injected into the membrane-free electrolytic cell. The electrolyte is a 1.5 M sodium iodide solution with a pH of 6.5. Air is removed from the membrane-free electrolytic cell. The membrane-free single cell is equipped with a hydrogen evolution electrode, an iodine evolution electrode, and a magnetic stirring unit. An external power supply is connected between the hydrogen electrode and the iodine evolution electrode. The voltage of the external power supply is 1.8V.

[0050] S2: Stir the electrolyte at a speed of 180 r / min, turn on the external power supply, and perform electrolytic hydrogen production. Iodine is produced at the iodine evolution electrode. S3: Collect the hydrogen gas evolved on the hydrogen evolution electrode, monitor the electrolysis voltage, and when its rise exceeds 20% of the initial electrolysis voltage and the electrolysis potential curve shows an inflection point, turn off the external power supply to interrupt the electrolysis hydrogen production.

[0051] S4: Inject the organic liquid phase into the electrolyte containing iodine. The injected organic liquid phase and the aqueous electrolyte phase will separate into layers, with the organic liquid phase layer being 10 cm thick. Continuously stir at a speed of 160 r / min to promote the extraction of iodine from the organic liquid phase. When the electrolyte returns to a colorless and clear state, and the organic liquid phase darkens in color, it indicates that the iodine has been completely extracted by the organic liquid phase. Collect all the organic liquid phase and a portion of the electrolyte together into the first container. The volume ratio of the organic liquid phase to the electrolyte is 5:1, and the organic liquid phase is n-hexane.

[0052] S5: Restart the external power supply to restart the electrolytic hydrogen production. Simultaneously, stir the liquid in the first container at a speed of 130 r / min. Add ascorbic acid to the first container to reduce elemental iodine and obtain dehydroascorbic acid. Elemental iodine is converted into iodide ions. The solubility of iodide ions in the electrolyte is much greater than their solubility in the organic liquid phase. At the same time, the solubility of dehydroascorbic acid in the electrolyte is also much greater than its solubility in the organic liquid phase. At this point, the electrolyte in the first container is rich in iodide ions and dehydroascorbic acid.

[0053] S6: While continuously producing hydrogen by electrolysis, the electrolyte rich in iodide ions and dehydroascorbic acid in the first container is returned to the electrolytic cell to replenish the electrolyte with iodide ions, thereby ensuring the continuity of hydrogen production by electrolysis. Dehydroascorbic acid is also introduced in this process, which is used to reduce the electrolysis potential and thus improve the electrolysis efficiency.

[0054] Steps S3 to S6 are repeated sequentially to cyclically produce hydrogen through electrolysis, thereby improving the efficiency of hydrogen production per unit time.

[0055] Example 4 S1: Sodium iodide electrolyte is injected into the membrane-free electrolytic cell. The electrolyte is a 1.7 M sodium iodide solution with a pH of 6.8. Air is removed from the membrane-free electrolytic cell. The membrane-free single cell is equipped with a hydrogen evolution electrode, an iodine evolution electrode, and a magnetic stirring unit. An external power supply is connected between the hydrogen electrode and the iodine evolution electrode. The voltage of the external power supply is 2V.

[0056] S2: Stir the electrolyte at a speed of 130 r / min, turn on the external power supply, and perform electrolytic hydrogen production. Iodine is produced at the iodine evolution electrode. S3: Collect the hydrogen gas evolved on the hydrogen evolution electrode, monitor the electrolysis voltage, and when its rise exceeds 20% of the initial electrolysis voltage and the electrolysis potential curve shows an inflection point, turn off the external power supply to interrupt the electrolysis hydrogen production.

[0057] S4: Inject the organic liquid phase into the electrolyte containing elemental iodine. The injected organic liquid phase and the aqueous electrolyte phase will separate into layers, with the organic liquid phase layer being 6 cm thick. Continuously stir at a speed of 170 r / min to promote the extraction of bromine / iodine from the organic liquid phase. When the electrolyte returns to a colorless and clear state, and the organic liquid phase darkens in color, it indicates that the bromine / iodine has been completely extracted by the organic liquid phase. Collect all the organic liquid phase and a portion of the electrolyte together into the first container. The volume ratio of organic liquid phase to electrolyte is 3:1, and the organic liquid phase is benzene.

[0058] S5: Restart the external power supply to restart the electrolytic hydrogen production. Simultaneously, stir the liquid in the first container at a speed of 150 r / min. Add ascorbic acid to the first container to reduce elemental iodine and obtain dehydroascorbic acid. Elemental iodine is converted into iodide ions. The solubility of iodide ions in the electrolyte is much greater than their solubility in the organic liquid phase. At the same time, the solubility of dehydroascorbic acid in the electrolyte is also much greater than its solubility in the organic liquid phase. At this point, the electrolyte in the first container is rich in iodide ions and dehydroascorbic acid.

[0059] S6: While continuously producing hydrogen by electrolysis, the electrolyte rich in iodide ions and dehydroascorbic acid in the first container is returned to the electrolytic cell to replenish the electrolyte with iodide ions, thereby ensuring the continuity of hydrogen production by electrolysis. Dehydroascorbic acid is also introduced in this process, which is used to reduce the electrolysis potential and thus improve the electrolysis efficiency.

[0060] Example 5 S1: The electrolyte for bromide ions is injected into a membrane-free electrolytic cell, which is equipped with a hydrogen evolution electrode and a bromine evolution electrode. Air is removed from the cell, and an external power source is connected between the hydrogen electrode and the bromine evolution electrode. The electrolyte for bromide ions is sodium bromide electrolyte. The voltage of the external power source is approximately 2.5 V.

[0061] S2: Stir the electrolyte at a speed of 140 r / min, turn on the external power supply, and perform electrolytic hydrogen production. Bromine / iodine elements are generated at the bromine evolution electrode. S3: Collect the hydrogen gas evolved on the hydrogen evolution electrode, monitor the electrolysis voltage, and when its rise exceeds 20% of the initial electrolysis voltage and the electrolysis potential curve shows an inflection point, turn off the external power supply to interrupt the electrolysis hydrogen production.

[0062] S4: Inject the organic liquid phase into the electrolyte containing elemental bromine. The injected organic liquid phase and the aqueous electrolyte phase will separate into layers, with the organic liquid phase layer being 4 cm thick. Continuously stir at a speed of 170 r / min to promote the extraction of bromine from the organic liquid phase. When the electrolyte returns to a colorless and clear state, and the organic liquid phase darkens in color, it indicates that the bromine has been completely extracted by the organic liquid phase. Collect all the organic liquid phase and a portion of the electrolyte together into the first container. The volume ratio of organic liquid phase to electrolyte is 4:1, and the organic liquid phase is butyl ether.

[0063] S5: Restart the external power supply to restart the electrolytic hydrogen production. Simultaneously, stir the liquid in the first container at a speed of 140 r / min. Add ascorbic acid to the first container to reduce elemental bromine and obtain dehydroascorbic acid. Elemental bromine is converted into bromide ions. The solubility of bromide ions in the electrolyte is much greater than their solubility in the organic liquid phase. At the same time, the solubility of dehydroascorbic acid in the electrolyte is also much greater than its solubility in the organic liquid phase. At this point, the electrolyte in the first container is rich in bromide ions and dehydroascorbic acid.

[0064] S6: While continuously producing hydrogen by electrolysis, the electrolyte rich in bromide ions and dehydroascorbic acid in the first container is refluxed back into the electrolytic cell to replenish the electrolyte with bromide ions, thereby ensuring the continuity of hydrogen production by electrolysis. Dehydroascorbic acid is also introduced in this process, which is used to reduce the electrolysis potential and thus improve the electrolysis efficiency.

[0065] Example 6 S1: The electrolyte containing iodide ions is injected into a membrane-free electrolytic cell. The cell is equipped with a hydrogen evolution electrode and an iodine evolution electrode. Air is removed from the cell, and an external power source is connected between the hydrogen electrode and the iodine evolution electrode. The electrolyte for iodide ions is sodium iodide electrolyte. The voltage of the external power source is approximately 3 V.

[0066] S2: Stir the electrolyte at a speed of 150 r / min, turn on the external power supply, and perform electrolytic hydrogen production, producing elemental iodine at the iodine evolution electrode.

[0067] S3: Collect the hydrogen gas evolved on the hydrogen evolution electrode, monitor the electrolysis voltage, and when its rise exceeds 20% of the initial electrolysis voltage and the electrolysis potential curve shows an inflection point, turn off the external power supply to interrupt the electrolysis hydrogen production.

[0068] S4: Inject the organic liquid phase into the electrolyte containing iodine. The injected organic liquid phase and the aqueous electrolyte phase will separate into layers, with the organic liquid phase layer being 3 cm thick. Continuously stir at a speed of 160 r / min to promote the extraction of bromine / iodine by the organic liquid phase. When the electrolyte returns to a colorless and clear state, and the organic liquid phase darkens in color, it indicates that the iodine has been completely extracted by the organic liquid phase. Collect all the organic liquid phase and a portion of the electrolyte together into the first container. The volume ratio of the organic liquid phase to the electrolyte is 4:1. The organic liquid phase is ethyl benzoate.

[0069] S5: Restart the external power supply to restart the electrolytic hydrogen production. Simultaneously, stir the liquid in the first container at a speed of 140 r / min. Add ascorbic acid to the first container to reduce elemental iodine and obtain dehydroascorbic acid. Elemental iodine is converted into iodide ions. The solubility of iodide ions in the electrolyte is much greater than their solubility in the organic liquid phase. At the same time, the solubility of dehydroascorbic acid in the electrolyte is also much greater than its solubility in the organic liquid phase. At this point, the electrolyte in the first container is rich in iodide ions and dehydroascorbic acid.

[0070] S6: While continuously producing hydrogen by electrolysis, the electrolyte rich in iodide ions and dehydroascorbic acid in the first container is returned to the electrolytic cell to replenish the electrolyte with iodide ions, thereby ensuring the continuity of hydrogen production by electrolysis. Dehydroascorbic acid is also introduced in this process, which is used to reduce the electrolysis potential and thus improve the electrolysis efficiency.

[0071] Steps S3 to S6 are repeated sequentially to cyclically produce hydrogen through electrolysis, thereby improving the efficiency of hydrogen production per unit time.

[0072] The above description is merely a specific embodiment of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. A method for hydrogen production via extraction-assisted membrane-free water electrolysis, characterized in that, It includes the following steps: S1: Inject the electrolyte containing bromide ions and / or iodide ions into a membrane-free electrolytic cell, which is equipped with a hydrogen evolution electrode and a bromine / iodine evolution electrode. Remove the air from the membrane-free electrolytic cell and connect the hydrogen electrode and the bromine / iodine evolution electrode to an external power source. S2: Stir the electrolyte, turn on the external power supply, and perform electrolytic hydrogen production. Bromine / iodine elements are generated at the bromine / iodine electrode. S3: Collect the hydrogen gas evolved on the hydrogen evolution electrode, monitor the electrolysis voltage, and when the voltage rises above a set value, turn off the external power supply to interrupt the electrolytic hydrogen production. S4: Inject the organic liquid phase into the electrolyte containing bromine / iodine, and stir continuously to promote the extraction of bromine / iodine by the organic liquid phase. Once the electrolyte returns to a colorless and clear state, recover all the organic liquid phase and part of the electrolyte together into the first container. S5: Restart the external power supply to restart the electrolytic hydrogen production. Simultaneously, stir the liquid in the first container and add ascorbic acid to the first container to reduce bromine / iodine, thereby obtaining dehydroascorbic acid. S6: While continuously producing hydrogen by electrolysis, the electrolyte in the first container is returned to the electrolytic cell to replenish bromide ions and / or iodide ions, thereby ensuring the continuity of hydrogen production by electrolysis. Dehydroascorbic acid is also added to reduce the electrolysis potential and thus improve the electrolysis efficiency.

2. The extraction-assisted membrane-free water electrolysis method for hydrogen production as described in claim 1, characterized in that, Steps S3 to S6 are repeated sequentially to cyclically produce hydrogen through electrolysis, thereby increasing the efficiency of hydrogen production per unit time.

3. The extraction-assisted membrane-free water electrolysis method for hydrogen production as described in claim 2, characterized in that, The electrolyte for bromide ions and / or iodide ions is sodium bromide electrolyte, sodium iodide electrolyte, or a mixture of both.

4. The extraction-assisted membrane-free water electrolysis method for hydrogen production as described in claim 3, characterized in that, The organic liquid phase is one or a mixture of several of the following: ethyl benzoate, n-hexane, benzene, and butyl ether.

5. The extraction-assisted membrane-free water electrolysis method for hydrogen production as described in claim 4, characterized in that, In step S4, the organic liquid phase is injected into an electrolyte containing bromine / iodine. The injected organic liquid phase and the aqueous electrolyte phase are separated into layers, and the thickness of the organic liquid phase layer is 2 cm to 10 cm.

6. The extraction-assisted membrane-free water electrolysis method for hydrogen production as described in claim 5, characterized in that, All organic liquid phase and part of electrolyte are recycled together into the first container, with the volume ratio of organic liquid phase to electrolyte being 2:1 to 5:

1.

7. The extraction-assisted membrane-free water electrolysis method for hydrogen production as described in claim 6, characterized in that, In step S3, the electrolysis voltage is monitored. When its rise exceeds 20% of the initial electrolysis voltage and the electrolysis potential curve shows an inflection point, the external power supply is turned off to interrupt the electrolysis hydrogen production.

8. The extraction-assisted membrane-free water electrolysis method for hydrogen production as described in any one of claims 1-7, characterized in that, All stirring speeds were 120 r / min to 180 r / min.

9. An apparatus for implementing the extraction-assisted membrane-free water electrolysis hydrogen production method as described in any one of claims 1-8, characterized in that, It includes a membrane-free single tank (1), a hydrogen evolution electrode (2), a bromine / iodine evolution electrode (3), a magnetic stirring unit (9), a first container (6), and a peristaltic pump (10), wherein, The membraneless single tank (1) is a covered box for holding electrolyte. The hydrogen evolution electrode (2) and the bromine / iodine evolution electrode (3) are placed in the membraneless single tank (1) and immersed in electrolyte. The magnetic stirring unit (9) is placed in the electrolyte to stir the electrolyte. The peristaltic pump (10) connects the membraneless single tank (1) and the first container (6).

10. The apparatus as claimed in claim 9, characterized in that, The top cover of the membraneless single tank (1) is equipped with a hydrogen outlet and an organic liquid phase inlet and outlet.

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