Method and system for producing hydrogen by electrolyzing seawater

Abstract

The invention provides a method for producing hydrogen by electrolyzing seawater, which comprises an electrode activation step: conveying an electrode active material into an anode cavity and / or a cathode cavity of an electrolysis module, so that the electrode active material is attached to the surface of an anode and / or a cathode to regenerate an electrode catalyst layer.

Description

Technical Field

[0001] The present invention relates to the technical field of seawater electrolysis, and in particular to a method and system for electrolyzing seawater. Background Art

[0002] Currently, the energy structure is gradually shifting from reliance on traditional fossil fuels to the pursuit of clean and efficient energy. Clean energy development has become a key force in accelerating my country's energy restructuring. Due to its unique energy properties, hydrogen has been established by many countries as a core energy carrier for the 21st century and has become a key growth pole for building a green, low-carbon energy system and promoting industrial upgrading. Hydrogen electrolysis, as the core production pathway for green hydrogen, is currently a research focus in the electrochemical energy field. Mainstream technologies include polymer exchange membrane electrolysis (including proton exchange membrane PEMWE and anion exchange membrane AEMWE) and alkaline water electrolysis (ALK). Research on hydrogen production from seawater electrolysis has significantly increased in recent years, but existing indirect seawater electrolysis technologies face two major bottlenecks: 1) the required high-cost seawater pretreatment process (such as desalination and organic matter removal); and 2) difficulty adapting to fluctuating renewable energy power supply. This prevents them from fully leveraging the nearly unlimited advantages of seawater resources. Direct seawater electrolysis technology has attracted much attention due to its simplified device and flexible coupling with intermittent power sources such as offshore wind power and wave energy. However, its electrode materials must meet stringent requirements: dynamic response capability: adapt to drastic fluctuations in energy input to maximize system energy efficiency; extreme environment tolerance: resist electrochemical corrosion and degradation by Cl-, OH-, OCl- plasma; anti-biological fouling properties: avoid electrode poisoning and inactivation caused by microorganisms and organic matter. The complex components of seawater have multiple destructive effects on the electrolysis system, causing poisoning and corrosion aging of the electrodes in the electrolyzer. Therefore, the mainstream electrolysis method is characterized by the water used undergoing pre-treatment processes such as deionization and de-organization, which is essentially an indirect method of hydrogen production by seawater electrolysis. This type of process is expensive and cumbersome, which hinders the large-scale production of hydrogen by seawater electrolysis.

[0003] Therefore, to address the issues of severe electrode corrosion, frequent side reactions, electrode passivation, poisoning, and short system lifespan in seawater electrolysis for hydrogen production, there is an urgent need to develop new corrosion-resistant, highly selective, and catalytically active electrode materials and structural designs to improve system efficiency and extend service life. Patent 202420341684.0 proposes an electrolyzer for direct seawater electrolysis to produce hydrogen, which is well suited to complex seawater operating conditions. However, the low activity of conductive diamond and the high voltage result in suboptimal system performance. Summary of the Invention

[0004] Based on the above-mentioned problems, it is necessary to provide a method for producing hydrogen by electrolyzing seawater, and a system using the method for producing hydrogen by electrolyzing seawater.

[0005] A method for producing hydrogen by electrolyzing seawater comprises the following steps:

[0006] Electrode activation steps:

[0007] The electrode active material is transported into the anode chamber and / or cathode chamber of the electrolysis module so that the electrode active material adheres to the anode and / or cathode surface to regenerate the electrode catalyst layer.

[0008] In one embodiment, during the electrode activation step, an oxygen evolution active material is delivered to the anode chamber, and a hydrogen evolution active material is delivered to the cathode chamber.

[0009] In one embodiment, the electrode active material is a liquid or a network / porous / foam active material catalyst layer containing active materials.

[0010] In one embodiment, the oxygen evolution active material includes a carbon / nitrogen single atom catalyst, and metal elements, alloys and compounds of platinum, iridium, ruthenium, gold, silver, palladium, rhodium, osmium, rhenium, nickel, iron, cobalt, manganese, zinc, molybdenum, tungsten, tantalum, titanium, niobium, zirconium and copper, wherein the compounds include but are not limited to one or more of oxides, hydroxides, layered double hydroxides, carbonitrides, sulfides, phosphides and metal organic frameworks MOF.

[0011] In one embodiment, the hydrogen evolution active material includes boron-doped carbon material, nitrogen-doped carbon material, graphite nitride, and one or more of metal elements, alloys, oxides, phosphides, sulfides, selenides, and nitrogen / carbon-added single atom catalysts of platinum, iridium, ruthenium, gold, silver, palladium, rhodium, osmium, rhenium, nickel, iron, cobalt, manganese, zinc, molybdenum, tungsten, tantalum, titanium, niobium, zirconium, and copper.

[0012] In one embodiment, the electrode activation step includes: sequentially delivering the electrode active material to the anode cavity more than once, and / or sequentially delivering the electrode active material to the cathode cavity more than once.

[0013] In one embodiment, a plating solution containing active materials is introduced into the anode chamber and / or cathode chamber, and the active materials are deposited on the surface of the anode and / or cathode by electroplating.

[0014] In one embodiment, the electrode activation step is: introducing a liquid containing active materials into the anode cavity and / or cathode cavity, and attaching the active materials to the surface of the anode and / or cathode through molecular self-assembly.

[0015] In one embodiment, the electrode activation step is: introducing a liquid containing active material into the anode chamber and / or cathode chamber to generate a catalyst on the surface of the anode and / or cathode by converting from a sacrificial precursor.

[0016] In one embodiment, the electrode activation step comprises circulating a liquid containing active materials into the anode chamber and / or cathode chamber.

[0017] In one embodiment, the process further includes a step of electrolyzing seawater: introducing seawater for electrolysis.

[0018] In one embodiment, the method further comprises an acid washing step, wherein the acid washing step is preceded by the electrode activation step by delivering an acid washing liquid into the anode chamber and / or cathode chamber of the electrolysis module.

[0019] A seawater electrolysis hydrogen production system is disclosed, wherein the seawater electrolysis hydrogen production system adopts any of the above-mentioned seawater electrolysis hydrogen production methods to electrolyze seawater.

[0020] The beneficial effects of the present invention are:

[0021] Efficient electrode reactivation can be achieved in situ in the electrolysis system, without the need to shut down and disassemble the electrolysis module for catalyst replacement or overall electrode replacement, thereby significantly reducing maintenance costs, shortening downtime, and extending the life of core electrode components, ensuring the long-term continuous operation and economy of the seawater electrolysis hydrogen production system. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0023] Figure 1 Flowchart of a method for producing hydrogen by electrolyzing seawater according to an embodiment of the present invention.

[0024] Figure 2 Schematic diagram of the structure of a seawater electrolysis hydrogen production system according to one embodiment of the present invention.

[0025] Figure 3 Schematic diagram of the structure of a seawater electrolysis hydrogen production system according to another embodiment of the present invention.

[0026] Figure 4 This is a comparison chart of activity changes after 1000 hours of initial active electrolysis operation of Example 1, Example 2, Example 3, Example 4 and Example 5 of the present invention before undergoing a reactivation process.

[0027] Figure 5 This is a performance comparison chart of Example 1, Example 2, Example 3, Example 4 and Example 5 of the present invention within 500 hours of operation after undergoing the reactivation process.

[0028] Figure 6 FIG. 1 is a graph showing the change of voltage over time during the electroplating process according to an embodiment of the present invention.

[0029] Figure 7This is an electron microscope image of a reactivation electrode using conductive diamond as a substrate according to an embodiment of the present invention.

[0030] Figure 8 This is an electron microscope image of a reactivated electrode using glassy carbon as a substrate according to one embodiment of the present invention. DETAILED DESCRIPTION

[0031] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0032] Seawater electrolysis is a potential pathway for producing green hydrogen from abundant seawater resources. However, practical applications of this technology face significant challenges, hindering its large-scale commercial development. These challenges stem from the complex working conditions of seawater, which can damage the electrolysis system, exacerbate electrode corrosion, and lead to the loss and deactivation of active catalysts.

[0033] The present invention provides a system and method for producing hydrogen by electrolyzing seawater, which can realize efficient electrode reactivation in situ in the electrolysis system. Specifically, Figure 1 As shown, the method for producing hydrogen by electrolyzing seawater includes the following steps:

[0034] Electrode activation steps:

[0035] The electrode active material is transported into the anode chamber and / or cathode chamber of the electrolysis module so that the electrode active material adheres to the anode and / or cathode surface to regenerate the electrode catalyst layer.

[0036] Among them, according to actual working conditions, the electrode active material can be transported to the anode cavity so that the electrode active material adheres to the anode to regenerate the anode catalyst layer, or the electrode active material can be transported to the cathode cavity so that the electrode active material adheres to the cathode to regenerate the cathode catalyst layer, or the electrode active material can be transported to the anode cavity and the cathode cavity so that the electrode active material adheres to the anode and cathode surfaces to regenerate the anode catalyst layer and the cathode catalyst layer.

[0037] The beneficial effects of this application are:

[0038] After the seawater electrolysis hydrogen production system has been running for a period of time, the electrode active materials are directly delivered to the anode cavity and / or cathode cavity of the electrolysis module, so that the electrode active materials adhere to the anode and / or cathode surface, and the electrodes are efficiently reactivated in situ. There is no need to shut down the electrolysis module to replace the catalyst or replace the entire electrode, thereby significantly reducing maintenance costs, shortening downtime, and extending the life of the core electrode components, ensuring the long-term continuous operation and economy of the seawater electrolysis hydrogen production system.

[0039] It should be understood that the operation process of this step is not synchronized with the seawater electrolysis process. Instead, the electrode activation process is performed after the seawater electrolysis process has been running for a certain period of time. After the electrode activation of the seawater electrolysis hydrogen production system is achieved, the seawater electrolysis process is performed.

[0040] Therefore, in one embodiment, the method for producing hydrogen by electrolyzing seawater of the present application further includes a step of electrolyzing seawater: introducing seawater into the electrolysis module, generating oxygen products at the anode and hydrogen products at the cathode through electrolysis.

[0041] The present application does not limit the order of the seawater electrolysis process and the electrode activation process, but determines when to perform the electrode activation process to reactivate the electrode based on the actual situation of the seawater electrolysis hydrogen production system.

[0042] Among them, in the seawater electrolysis hydrogen production system, the anode chamber and the cathode chamber are independent of each other, the oxygen evolution reaction occurs at the anode, and the hydrogen evolution reaction occurs at the cathode. Therefore, in one embodiment, in the electrode activation step, the oxygen evolution active material is transported to the anode chamber to activate the anode catalyst layer, and the hydrogen evolution active material is transported to the cathode chamber to activate the cathode catalyst layer.

[0043] In one embodiment, the oxygen evolution active material includes a carbon / nitrogen single atom catalyst and metal elements, alloys, and compounds of platinum, iridium, ruthenium, gold, silver, palladium, rhodium, osmium, rhenium, nickel, iron, cobalt, manganese, zinc, molybdenum, tungsten, tantalum, titanium, niobium, zirconium, and copper. The compounds include, but are not limited to, one or more oxides, hydroxides, layered double hydroxides, carbonitrides, sulfides, phosphides, and metal organic frameworks (MOFs), such as PtNi, IrCo, NiFe, CoFe, NiO, IrO2, RuO2, Ni(OH)2, Co(OH)2, NC, Fe–N–C, Fe–N4, Co–N4, Ni–N4, NiFe-LDH, CoFe-LD, NiCo-LDH, and Co / Zn-porphyrin MOFs. For example, the oxygen evolution active material is iridium oxide, and for another example, the oxygen evolution active material includes iridium oxide and ruthenium oxide. These are not listed in detail in this embodiment. By introducing any of the above active materials into the anode cavity, the active materials are attached to the anode surface to achieve in-situ regeneration of the anode catalyst layer.

[0044] In one embodiment, the hydrogen evolution active material includes a boron-doped carbon material, a nitrogen-doped carbon material, a graphite nitride, and one or more of a metal element, alloy, oxide, phosphide, sulfide, selenide, or nitrogen / carbon-added single-atom catalyst of platinum, iridium, ruthenium, gold, silver, palladium, rhodium, osmium, rhenium, nickel, iron, cobalt, manganese, zinc, molybdenum, tungsten, tantalum, titanium, niobium, zirconium, or copper. Such as NiFe, CoFe, IrO2, Ni2P, CoP, MoS2, WS2, NiSe2, CoSe, B / NC, g-C3N4, etc. Wherein, for example, the hydrogen evolution active material is a platinum-cobalt alloy, and for example, the hydrogen evolution active material is a platinum-nickel alloy, and for example, the hydrogen evolution active material is molybdenum disulfide. In this embodiment, they are not described one by one. By introducing any of the above active materials into the cathode cavity, the active material is attached to the cathode surface to achieve in-situ regeneration of the cathode catalyst layer.

[0045] Regarding the method of reactivating the electrode, in one embodiment, the electrode active material is a liquid containing an active material or a mesh / porous / foamed active material catalyst layer. That is, for example, the electrode active material is a liquid containing an active material, and the liquid containing the active material is introduced into the anode cavity and / or cathode cavity, and the active material is attached to the electrode surface by electrolysis to achieve in-situ regeneration of the electrode catalyst layer. Specifically, for example, an electroplating solution containing the active material is introduced into the anode cavity and / or cathode cavity, and the active material is deposited on the surface of the anode and / or cathode by electroplating, or a liquid containing the active material is introduced into the anode cavity and / or cathode cavity, and attached to the surface of the anode and / or cathode by molecular self-assembly, or a liquid containing the active material is introduced into the anode cavity and / or cathode cavity, and a catalyst is generated on the surface of the anode and / or cathode by conversion from a sacrificial precursor. Furthermore, if the electrode active material is a mesh / porous / foamed active material catalyst layer, the mesh active material catalyst layer is extended into the electrolysis cavity through an external structure so that it is attached to the electrode surface to achieve in-situ regeneration of the electrode catalyst layer.

[0046] To reactivate the electrode, for example, the electrode activation step includes: sequentially delivering the electrode active material to the anode chamber one or more times, and / or sequentially delivering the electrode active material to the cathode chamber one or more times. In one embodiment, the electrode active material is sequentially delivered to the anode chamber two or more times. Specifically, the electroplating solution containing the active material is sequentially delivered to the anode chamber two or more times, i.e., electroplating solution 1 is introduced into the anode chamber, followed by electroplating solution 2, and finally electroplating solution N, to electrolytically plate the active material on the anode surface. If the electrode active material is introduced into the cathode chamber, the process is the same as described above and is not described in detail in this embodiment.

[0047] Wherein, in the above-mentioned electrode activation process, the number of times the electrode active material is delivered is set according to actual conditions, and the delivered electrode active materials can be the same or different. In one embodiment, the electrode activation step is as follows: an electroplating solution 1 containing iridium oxide is introduced into the anode cavity, and then an electroplating solution 2 containing ruthenium oxide is introduced. In another embodiment, the electrode activation step is as follows: an electroplating solution 1 containing iridium oxide is introduced into the anode cavity, and then an electroplating solution 2 containing iridium oxide is introduced for secondary electroplating. If the electrode active material is introduced into the cathode cavity, the same as above is applied, and in this embodiment, they are not described one by one.

[0048] The present application provides a method for producing hydrogen by electrolyzing seawater according to an embodiment, wherein a plating solution containing active materials is used in the reactivation process to plate the active materials on the electrode surface by electroplating. Figure 5 As shown in the figure, it is a graph showing the change of voltage over time during the electroplating process. The process is constant current stage electroplating, and the process is as follows:

[0049] Phase 1: 5s, 0 current density rest, voltage balance;

[0050] Second stage: 60s, high current density electroplating, 20-25mA / cm 2 ;

[0051] Phase 3: 5s, 0 current density rest, voltage balance;

[0052] Stage 4: Until -400s, low current density electroplating, 4-5mA / cm 2 .

[0053] Based on the fact that the transported active material is a liquid containing the active material, for example, the electrode activation step is: circulating the liquid containing the active material into the anode cavity and / or the cathode cavity. Specifically, in one embodiment, the plating solution containing the active material is circulated into the anode cavity and / or the cathode cavity, so that the plating solution circulates between the storage module (or transport module) and the electrolysis cavity (anode cavity and / or cathode cavity), so that the active material can be more evenly dispersed on the surface of the electrode during the electroplating process, that is, the reactivated catalyst layer is more uniform, thereby improving the electrolysis performance.

[0054] To improve the electrolytic performance of the reactivated catalyst layer, one embodiment further includes an acid wash step. Prior to the electrode activation step, the acid wash step involves delivering an acid wash liquid to the anode and / or cathode chambers of the electrolysis module. This means that before activating the electrodes, the acid wash liquid is introduced to corrode any remaining catalyst layer on the electrode surfaces, thereby making the reactivated catalyst layer more uniform and improving electrolytic performance.

[0055] The present invention also provides a system for producing hydrogen by electrolyzing seawater, such as Figure 2 and Figure 3As shown, specifically, it includes an electrolysis module 1 and an active material delivery module 2 .

[0056] The electrolysis module 1 includes a housing and a plurality of electrolysis cells disposed within the housing. The electrolysis cells include an anode, an electrolyte membrane, and a cathode disposed in sequence. The electrolyte membrane separates the anode and the cathode, forming independent anode and cathode cavities on either side of the electrolyte membrane. In other words, the anode and cathode cavities are independent, mutually separated chambers. During the electrolysis process, an oxygen evolution reaction occurs in the anode cavity to produce oxygen products, while a hydrogen evolution reaction occurs in the cathode cavity to produce hydrogen products.

[0057] The active material delivery module 2 is used to deliver electrode active materials to the anode cavity and / or the cathode cavity, so that the electrode active materials adhere to the surface of the first electrode and / or the second electrode.

[0058] Among them, the active material delivery module 2 is used to store and deliver electrode active materials to the electrolysis chamber (anode chamber and / or cathode chamber), oxygen evolution reaction occurs at the anode, and hydrogen evolution reaction occurs at the cathode. Therefore, in one embodiment, the active material delivery module includes an oxygen-end active material delivery unit and a hydrogen-end active material delivery unit. The oxygen-end active material delivery unit is used to deliver oxygen evolution active materials to the anode chamber, and the hydrogen-end active material delivery unit is used to deliver hydrogen evolution active materials to the cathode chamber.

[0059] In one embodiment, the hydrogen evolution active material includes a metal element of platinum / iridium / ruthenium, an alloy of nickel / iron / cobalt / platinum, a metal oxide of iridium / ruthenium / nickel, a phosphide of nickel / cobalt / iron / molybdenum / phosphorus, a sulfide of molybdenum / tungsten / nickel / cobalt / sulfur, a selenide of nickel / cobalt / molybdenum / selenium, a single atom catalyst of iron / cobalt / nickel plus nitrogen / carbon, a boron / nitrogen doped carbon material, or one or more of graphite nitride. For example, the oxygen evolution active material is iridium oxide, and for example, the oxygen evolution active material includes iridium oxide and ruthenium oxide. In this embodiment, they are not described one by one. By introducing any of the above active materials into the anode cavity, the active material is plated on the anode surface to achieve in situ regeneration of the anode catalyst layer.

[0060] In one embodiment, the hydrogen evolution active material includes a metal element of platinum / iridium / ruthenium, an alloy of nickel / iron / cobalt / platinum, a metal oxide of iridium / ruthenium / nickel, a phosphide of nickel / cobalt / iron / molybdenum / phosphorus, a sulfide of molybdenum / tungsten / nickel / cobalt / sulfur, a selenide of nickel / cobalt / molybdenum / selenium, a single atom catalyst of iron / cobalt / nickel plus nitrogen / carbon, a boron / nitrogen-doped carbon material, or one or more of graphite nitride. For example, the hydrogen evolution active material is a platinum-cobalt alloy, and for example, the hydrogen evolution active material includes a platinum-cobalt alloy and a platinum-nickel alloy. In this embodiment, they are not described one by one. By introducing any of the above active materials into the cathode cavity, the active material is plated on the cathode surface to achieve in situ regeneration of the cathode catalyst layer.

[0061] To reactivate the electrode, in one embodiment, the electrode active material is a liquid containing active material, and the active material delivery module delivers the liquid containing active material to the anode cavity and / or the cathode cavity, so that the active material liquid adheres to the anode and / or the cathode surface, so as to achieve in situ regeneration of the electrode catalyst layer; for another example, the electrode active material is a mesh / porous / foam-like active material catalyst layer, and the active material delivery module is used to deliver the mesh / porous / foam-like material layer to the anode cavity and the cathode cavity, and extend the mesh / porous / foam-like active material catalyst layer into the electrolysis cavity through the external structure so that it adheres to the electrode surface, so as to achieve in situ regeneration of the electrode catalyst layer.

[0062] In one embodiment, the substrate material of the electrode is one or more of gold, silver, platinum, palladium, rhodium, iridium, ruthenium, osmium, rhenium, tantalum, niobium, zirconium, molybdenum, rhenium, titanium, nickel, copper, high-purity aluminum, titanium alloy, nickel-based alloy, aluminum alloy, copper-based alloy, stainless steel, silicon, germanium, conductive diamond, gallium arsenide, indium phosphide, gallium nitride, cadmium sulfide, cadmium selenide, cadmium telluride, zinc oxide, titanium dioxide, tin oxide, indium tin oxide, zinc aluminum oxide, silicon germanium, organic semiconductor, polyaniline, polypyrrole, polythiophene and its derivatives, polyacetylene, carbon-based filler composite material, metal filler composite material, metal-plated filler composite material, silicone rubber or fluororubber with conductive filler added to the conductive elastomer. The active material is attached to the surface of the substrate material to achieve in-situ regeneration of the electrode catalyst layer.

[0063] In one embodiment, the active material transport module is connected to the anode chamber or cathode chamber via a circulation line, where the transported active material is a liquid containing the active material. In other words, the liquid circulates between the active material transport module and the electrolysis chamber (anode chamber and / or cathode chamber). This circulation process can more evenly disperse the active material on the surface of the electrode, resulting in a more uniform reactivated catalyst layer and improved electrolysis performance.

[0064] To improve the electrolytic performance of the reactivated catalyst layer, in one embodiment, the seawater electrolysis hydrogen production system further includes an acid wash module that delivers an acid wash liquid to the anode chamber and / or cathode chamber. Before activating the electrodes, the acid wash liquid is introduced to corrode any residual catalyst layer on the electrode surface, thereby making the reactivated catalyst layer more uniform and improving electrolytic performance.

[0065] This application provides specific examples to verify the performance of the electrolysis hydrogen production system of the reactivated electrode.

[0066] Example 1

[0067] A conductive diamond electrode substrate is used, the cathode catalyst is PtNi, and the anode catalyst is IrRuO2.

[0068] The same PtNi is selected as the hydrogen evolution active material and transported to the cathode cavity, and the same IrRuO2 is selected as the oxygen evolution active material and transported to the anode cavity.

[0069] Example 2

[0070] A conductive diamond electrode substrate is used, the cathode catalyst is PtNi, and the anode catalyst is IrRuO2.

[0071] FeCoW was selected as the oxygen evolution active material and transported to the anode cavity, and the cathode catalyst was not reactivated.

[0072] Example 3

[0073] A glassy carbon substrate is used, the cathode catalyst is PtNi, and the anode catalyst is IrRuO2.

[0074] The same PtNi is selected as the hydrogen evolution active material and transported to the cathode cavity, and the same IrRuO2 is selected as the oxygen evolution active material and transported to the anode cavity.

[0075] Example 4

[0076] A conductive diamond electrode substrate is used, the cathode catalyst is PtNi, and the anode catalyst is IrRuO2.

[0077] No electrode reactivation was performed at the cathode or anode.

[0078] Example 5

[0079] A conductive diamond electrode substrate is used, the cathode catalyst is PtNi, and the anode catalyst is IrRuO2.

[0080] The same IrRuO2 was selected as the oxygen evolution active material and transported to the anode cavity, and the cathode catalyst was not reactivated.

[0081] Among them, in the above-mentioned Examples 1-5, the anode catalyst is IrRuO2 and the cathode catalyst is PtNi.

[0082] Example 1: Both the cathode and the anode are reactivated with the same active material as the original catalyst layer.

[0083] Example 2: The anode is reactivated with an active material different from that of the original catalyst layer, and the cathode is no longer activated, which is a comparative example with Example 1.

[0084] Example 3: Both the cathode and the anode are reactivated with the same active material as the original catalyst layer, and only the substrate material is different from that of Example 1. This is a comparative example with Example 1.

[0085] Example 4: A blank control group in which both the cathode and the anode were not reactivated.

[0086] Example 5: The anode is reactivated with the same active material as the original catalyst layer, and the cathode is no longer activated. This is a comparative example with Example 1 and Example 2.

[0087] See Figure 3 , which is a comparison chart of activity changes after 1000 hours of initial active electrolysis operation of Example 1, Example 2, Example 3, Example 4 and Example 5 before the reactivation process, under the same constant current working condition of 0.4 A / cm2.

[0088] See Figure 4 , which is a performance comparison chart of Example 1, Example 2, Example 3, Example 4 (no longer activated) and Example 5 after the reactivation process, under the same constant current working condition of 0.4A / cm2, within 500h of operation.

[0089] As can be seen from the above figures, after a long period of operation, the electrolytic cell with reactivated electrodes performs significantly better than the non-reactivated one. In other words, after electrode reactivation, its performance is significantly restored, and reactivation can be based on different materials. The seawater electrolysis hydrogen production method of the present application can efficiently activate the electrodes in situ, ensuring the long-term continuous operation and economic efficiency of the seawater electrolysis hydrogen production system.

[0090] The present application provides a method for producing hydrogen by electrolyzing seawater, which uses any of the seawater electrolysis hydrogen production systems described above to electrolyze seawater.

[0091] It should be understood that in order to realize the operation of the seawater electrolysis hydrogen production system, Figure 3 As shown, the present application also includes modules required by existing seawater electrolysis hydrogen production systems, such as a seawater supply module 3, a power supply module, a gas-liquid separation module 4, a hydrogen storage module, and an oxygen storage module, which are not listed one by one in this application.

[0092] The technical features of the above-mentioned embodiments can be combined arbitrarily. In order to make the description concise, not all possible combinations of the technical features in the above-mentioned 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.

[0093] The above-described embodiments merely illustrate several implementations of the present invention, and while their descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the patent. It should be noted that a person skilled in the art would be able to make numerous variations and improvements without departing from the spirit of the present invention, all of which fall within the scope of protection of the present invention. Therefore, the scope of protection of the patent for this invention shall be determined by the appended claims.

Claims

1. A method for producing hydrogen by electrolyzing seawater, characterized in that: The steps include: Electrode activation steps: The electrode active material is transported into the anode chamber and / or cathode chamber of the electrolysis module so that the electrode active material adheres to the anode and / or cathode surface to regenerate the electrode catalyst layer.

2. The method for producing hydrogen by electrolyzing seawater according to claim 1, wherein: In the electrode activation step, oxygen evolution active material is transported to the anode cavity, and hydrogen evolution active material is transported to the cathode cavity.

3. The method for producing hydrogen by electrolysis of seawater according to claim 1, wherein: The electrode active material is a liquid containing active material or a network / porous / foamy active material catalyst layer.

4. The method for producing hydrogen by electrolyzing seawater according to claim 1, wherein: The oxygen evolution active material includes a carbon / nitrogen single atom catalyst, and metal elements, alloys and compounds of platinum, iridium, ruthenium, gold, silver, palladium, rhodium, osmium, rhenium, nickel, iron, cobalt, manganese, zinc, molybdenum, tungsten, tantalum, titanium, niobium, zirconium and copper, wherein the compound includes but is not limited to one or more of oxides, hydroxides, layered double hydroxides, carbonitrides, sulfides, phosphides and metal organic frameworks (MOFs).

5. The method for producing hydrogen by electrolyzing seawater according to claim 1, wherein: The hydrogen evolution active material includes boron-doped carbon material, nitrogen-doped carbon material, graphite nitride, and one or more of metal elements, alloys, oxides, phosphides, sulfides, selenides, and nitrogen / carbon-added single-atom catalysts of platinum, iridium, ruthenium, gold, silver, palladium, rhodium, osmium, rhenium, nickel, iron, cobalt, manganese, zinc, molybdenum, tungsten, tantalum, titanium, niobium, zirconium, and copper.

6. The method for producing hydrogen by electrolyzing seawater according to claim 1, 2 or 3, wherein: The electrode activation step includes: sequentially delivering the electrode active material to the anode cavity more than once, and / or sequentially delivering the electrode active material to the cathode cavity more than once.

7. The method for producing hydrogen by electrolyzing seawater according to claim 1, wherein: The electrode activation step comprises: introducing an electroplating solution containing active materials into the anode cavity and / or cathode cavity, and depositing the active materials on the surface of the anode and / or cathode by electroplating.

8. The method for producing hydrogen by electrolyzing seawater according to claim 1, wherein: The electrode activation step comprises: introducing a liquid containing active materials into the anode cavity and / or cathode cavity, and attaching the liquid to the surface of the anode and / or cathode through a molecular self-assembly method.

9. The method for producing hydrogen by electrolyzing seawater according to claim 1, wherein: The electrode activation step comprises: introducing a liquid containing active material into the anode cavity and / or cathode cavity, and generating a catalyst on the surface of the anode and / or cathode through conversion from a sacrificial precursor.

10. The method for producing hydrogen by electrolyzing seawater according to claim 7, 8 or 9, characterized in that: The electrode activation step comprises circulating a liquid containing active materials into the anode cavity and / or cathode cavity.

11. The method for producing hydrogen by electrolyzing seawater according to claim 1, wherein: The method also includes a seawater electrolysis step: introducing seawater for electrolysis.

12. The method for producing hydrogen by electrolyzing seawater according to claim 1, wherein: The method further comprises an acid washing step, wherein before the electrode activation step, the acid washing step comprises delivering an acid washing liquid into the anode chamber and / or cathode chamber of the electrolysis module.

13. A system for producing hydrogen by electrolyzing seawater, characterized in that: The seawater electrolysis hydrogen production system adopts the seawater electrolysis hydrogen production method according to any one of claims 1 to 12 to electrolyze seawater.

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