System and method for producing hydrogen by coupling photo-thermal membrane distillation and photovoltaic electrolysis of seawater vapor

Abstract

The invention discloses a system and a method for hydrogen production by coupling photo-thermal membrane distillation and photovoltaic electrolysis of seawater vapor, and relates to the technical field of electrolytic hydrogen production. The system comprises a material management unit, a photovoltaic power generation unit, a photovoltaic power generation monitoring unit and a photo-thermal electrolytic cell, and a photo-thermal film and a PEM electrolytic cell are integrated in the photo-thermal electrolytic cell, and the photo-thermal electrolytic cell is used for absorbing solar energy and heating seawater from the high-level water tank to generate water vapor, and meanwhile, the generated water vapor is electrolyzed to generate hydrogen and oxygen by utilizing electric energy provided by the photovoltaic power generation unit. According to the system, photovoltaic photo-thermal and a seawater desalination-PEM electrolytic hydrogen production system are coupled, double efficient conversion of'light-electricity 'and'light-heat' of renewable energy solar energy is achieved, the energy utilization efficiency of the whole system is improved, other external energy input is not needed, and high-purity energy hydrogen can be obtained only through solar energy and seawater.

Description

Technical Field

[0001] This invention relates to the field of electrolytic hydrogen production technology, specifically to a photothermal film distillation coupled with photovoltaic electrolysis of seawater steam to produce hydrogen system and method. Background Technology

[0002] Driven by both global goals and energy structure transformation, hydrogen energy, as a clean, efficient, and storable secondary energy source, is widely regarded as a key vehicle for replacing traditional fossil fuels and building a new energy system. Among these technologies, renewable energy-based hydrogen production has become a research hotspot in the energy field because it can eliminate carbon emissions at the source. Furthermore, the coupled application of solar energy, as the most abundant and easily accessible renewable energy source, with hydrogen production technology is one of the core directions for solving the challenge of large-scale hydrogen production.

[0003] Seawater, as the most abundant water resource, is an ideal raw material for achieving large-scale green hydrogen energy production and reducing reliance on freshwater. However, both current mainstream technologies for renewable energy-based seawater electrolysis to produce hydrogen face significant bottlenecks. Indirect hydrogen production relies on a separate seawater desalination system, which suffers from inherent drawbacks such as lengthy processes, cumulative energy consumption, and low system efficiency. Direct seawater electrolysis, which aims to simplify the process, struggles to overcome challenges such as chloride ion corrosion, catalyst poisoning, and proton exchange membrane fouling, and is particularly incompatible with PEM electrolyzers that require extremely high feed water purity.

[0004] Some existing improvement schemes attempt to alleviate the above contradictions, but none have achieved a fundamental breakthrough. For example, the device disclosed in patent application CN202410528947.3 attempts coupling, but uses an alkaline electrolyzer with relatively low hydrogen purity and current density, and the system structure is complex and the coupling tightness is insufficient. Another patent application CN202122361322.7 still relies on an external thermal processor to heat the seawater and a pre-installed seawater purification system to produce liquid pure water, failing to achieve efficient in-situ utilization of solar energy and deep synergy of material energy. There is still room for improvement in system integration and energy efficiency.

[0005] Current renewable energy-based seawater electrolysis hydrogen production technology faces prominent challenges, including low overall solar energy utilization efficiency, poor system integration, high energy costs, and insufficient synergy between water resources and energy. Therefore, developing an integrated system that enables the cascaded utilization of photovoltaic and solar thermal energy and the deep coupling of seawater desalination and electrolysis hydrogen production, thereby improving the energy efficiency and economic viability of hydrogen production through efficient energy conversion and optimized material allocation, has become an urgent need to promote the large-scale application of seawater hydrogen production technology. Summary of the Invention

[0006] The purpose of this invention is to provide a photothermal film distillation coupled photovoltaic electrolysis seawater steam hydrogen production system and method, which solves the problems in the background technology. By coupling photovoltaic photothermal with seawater desalination-PEM electrolysis hydrogen production system, the dual high-efficiency conversion of renewable energy solar energy into "photo-electricity" and "photo-thermal" is realized, improving the energy utilization efficiency of the entire system. High-purity energy hydrogen can be obtained with only solar energy and seawater without the need for other external energy input.

[0007] To achieve the above objectives, the present invention provides a photothermal film distillation coupled with photovoltaic electrolysis of seawater steam to produce hydrogen, including a material management unit, a photovoltaic power generation unit, a photovoltaic power generation monitoring unit, and a photothermal electrolysis cell; The material management unit includes an elevated water tank and a hydrogen collection tank. The elevated water tank is used to store seawater and supply seawater to the photothermal electrolysis cell by gravity. The photovoltaic power generation unit is used to convert solar energy into electrical energy and to supply power to the photothermal electrolysis cell; The photovoltaic power generation monitoring unit is used to monitor the electrical output parameters of the photovoltaic power generation unit in real time; The photothermal electrolysis cell integrates a photothermal film and a PEM electrolysis cell, which is used to absorb solar energy and heat seawater from the high-level water tank to generate water vapor. At the same time, the generated water vapor is electrolyzed to generate hydrogen and oxygen using the electrical energy provided by the photovoltaic power generation unit. The hydrogen collection tank is used to collect the hydrogen produced by the photothermal electrolyzer.

[0008] Preferably, the photothermal electrolysis cell includes an anode plate and a cathode plate. A photothermal film is disposed on the outer side of the anode plate, and a proton exchange membrane is disposed at the center of the anode plate and the cathode plate. A catalytic layer and a diffusion layer are symmetrically disposed at both ends of the proton exchange membrane.

[0009] An air gap is formed between the photothermal film and the anode plate to allow water vapor to diffuse and oxygen to escape. A seawater channel is provided on the side of the photothermal film away from the anode plate.

[0010] Preferably, the photovoltaic power generation monitoring unit includes a current sensor, a voltage sensor, and a DC-DC converter. The anode plate and the cathode plate are both connected to the photovoltaic power generation unit. The current sensor and the DC-DC converter are sequentially arranged at the connection points between the anode plate, the cathode plate, and the photovoltaic power generation unit. The voltage sensor is electrically connected to both sides of the photothermal electrolysis cell.

[0011] Preferably, the material management unit further includes a circulation pipeline for transporting the remaining unevaporated seawater in the photothermal electrolysis cell back to the high-level water tank.

[0012] Preferably, the elevated water tank is placed at a higher position than the photothermal electrolysis cell.

[0013] Preferably, the photothermal film is a hydrophobic porous film with photothermal conversion function; The diffusion layer is any one of titanium mesh, titanium felt, or titanium foam; The catalyst layer includes an anode catalyst layer near the anode end plate and a cathode catalyst layer near the cathode end plate. The catalyst of the anode catalyst layer is IrO2, and the catalyst of the cathode catalyst layer is platinum / carbon. The proton exchange membrane is a perfluorosulfonic acid membrane.

[0014] Preferably, in the photothermal film distillation coupled photovoltaic electrolysis seawater steam hydrogen production system, under standard conditions of 0℃ and 101.325kPa, the conversion relationship between current density and hydrogen production volume is as follows: in, For hydrogen production volume, The effective reaction area of ​​the electrode plate. It is Faraday's constant. For time, This is the integral of the current density-time curve.

[0015] This invention also provides a method for producing hydrogen from seawater steam by photothermal film distillation coupled with photovoltaic electrolysis using the above system, comprising the following steps: (1) Seawater is transported to the seawater channel at the photothermal electrolysis cell by gravity through an elevated water tank; (2) The photothermal film on the PEM electrolytic cell is irradiated by sunlight to generate heat to heat the flowing seawater. The water vapor generated by the evaporation of seawater passes through the photothermal film and enters the interior of the electrolytic cell. (3) Solar energy is converted into electrical energy using photovoltaic panels and the electrical energy is connected to the anode and cathode of the PEM electrolytic cell; (4) Water vapor passes through the diffusion layer in the electrolytic cell and reaches the anode catalyst layer in sequence. It undergoes an electrochemical reaction and decomposes into oxygen and protons. The protons pass through the proton exchange membrane and reach the cathode catalyst layer. A reduction reaction occurs in the cathode catalyst layer to synthesize hydrogen. The hydrogen is then introduced into the hydrogen collection tank. (5) The seawater that remains after passing through the photothermal membrane and has increased concentration flows into and returns to the high-level water tank by the power of water flow. On the one hand, the residual heat can be put into the water tank, and on the other hand, it can be recycled.

[0016] Therefore, the present invention has the following beneficial effects: 1. This invention fully utilizes solar energy, directly driving electrolysis through photovoltaic power generation, while simultaneously leveraging the photothermal effect to efficiently generate the pure steam required for electrolysis. This system avoids the waste of waste heat from traditional photovoltaic systems, significantly improving the overall solar energy conversion efficiency. Furthermore, the use of membrane distillation physical isolation technology reduces the interference of seawater impurities on the electrolysis process, ensuring that the PEM electrolyzer always operates in a pure steam environment, thereby stably producing high-purity hydrogen.

[0017] 2. This invention achieves a high degree of integration of seawater desalination and electrolytic hydrogen production in a single system by coupling photothermal membrane distillation with a PEM electrolyzer. This design allows seawater to be directly introduced into the system, completing the entire process of heating-evaporation-purification-electrolysis within the device, eliminating the need for a separate, energy-intensive seawater pretreatment unit, significantly simplifying the system structure and reducing equipment and maintenance costs. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of the connection of the photothermal film distillation coupled with photovoltaic electrolysis seawater steam to produce hydrogen system in Embodiment 1 of the present invention; Figure 2 This is a schematic diagram of the internal assembly of the photothermal electrolysis cell in Embodiment 1 of the present invention; Figure 3 This is a graph showing the change of light intensity over time in Embodiment 3 of the present invention; Figure 4 This is a graph showing the voltage across the photothermal electrolysis cell in Embodiment 3 of the present invention as a function of time. Figure 5 This is a graph showing the change in charge load over time of the effective reaction area of ​​the cathode in Example 3 of the present invention. Figure Labels 1. High-level water tank; 2. Photovoltaic power generation unit; 3. DC-DC converter; 4. Photothermal source; 5. Hydrogen collection tank; 6. Current sensor; 7. Voltage sensor; 8. Photothermal electrolysis cell; 9. Flow channel; 10. Photothermal film; 101. Membrane pores; 11. Air gap; 12. Anode diffusion layer; 13. Anode catalyst layer; 14. Proton exchange membrane; 15. Cathode catalyst layer; 16. Cathode diffusion layer; 17. Anode end plate; 18. Cathode end plate. Detailed Implementation

[0019] The technical solution of the present invention will be further described below with reference to the accompanying drawings and embodiments.

[0020] Unless otherwise defined, the technical or scientific terms used in this invention shall have the ordinary meaning as understood by one of ordinary skill in the art to which this invention pertains.

[0021] Furthermore, it should be understood that although this specification describes embodiments, not every embodiment contains only one independent technical solution. This narrative style is merely for clarity. Those skilled in the art should consider the specification as a whole, and the technical solutions in each embodiment can be appropriately combined to form other embodiments that can be understood by those skilled in the art. These other embodiments are also covered within the scope of protection of this invention.

[0022] Example 1 This embodiment provides a photothermal film distillation coupled with photovoltaic electrolysis of seawater steam to produce hydrogen. For example... Figure 1 As shown, the system mainly includes a material management unit, a photovoltaic power generation unit 2, a photovoltaic power generation monitoring unit, and the core photothermal electrolysis cell 8.

[0023] Material Management Unit: This unit is responsible for the supply, circulation and product collection of the system's raw materials, and mainly consists of a high-level water tank 1, circulation pipelines and hydrogen collection tank 5.

[0024] The elevated water tank 1, used for storing raw seawater and supplying fresh seawater, is placed at a higher position in the system, above the photothermal electrolysis cell 8. The seawater flows naturally downstream due to gravity generated by this height difference, eliminating the need for an additional pump and reducing system energy consumption and complexity.

[0025] The circulation pipeline is connected between the concentrated seawater outlet of the photothermal electrolysis cell 8 and the high-level water tank 1. It is used to transport the remaining seawater that has not evaporated and has increased in concentration after flowing through the electrolysis cell back to the high-level water tank 1, so as to realize waste heat recovery and material recycling.

[0026] The hydrogen collection tank 5 is connected to the cathode exhaust port of the photothermal electrolysis cell 8 via a pipeline, and is used to collect and store the high-purity hydrogen produced by electrolysis.

[0027] Photovoltaic power generation unit 2 and photovoltaic power generation monitoring unit: In this embodiment, photovoltaic power generation unit 2 is composed of photovoltaic panels. Its core function is to directly convert solar energy into DC power to provide a power source for the entire electrolysis process.

[0028] The photovoltaic power generation monitoring unit is used to sense the output status of photovoltaic power generation unit 2 in real time and with high accuracy. This unit includes a current sensor 6, a voltage sensor 7, and a DC-DC converter 3.

[0029] Both the anode plate 17 and the cathode plate 18 are electrically connected to the photovoltaic power generation unit 2, forming the main power supply circuit of the system. A current sensor 6 and a DC-DC converter 3 are connected in series in this circuit. The current sensor 6 is used to measure the system's operating current I(t) in real time, which is related to the calculation of the real-time hydrogen production volume. The voltage sensor 7 is connected in parallel between the anode plate 17 and the cathode plate 18 of the photothermal electrolyzer 8, and is used to directly measure the operating voltage.

[0030] The photovoltaic power generation monitoring unit dynamically stabilizes the electrolyzer voltage within the PEM high-efficiency electrolysis range (1.6 V to 2.2 V). Based on the feedback signal from the voltage sensor 7, it determines whether the voltage is within the optimal range and adjusts it using the DC-DC converter 3, thereby achieving precise control of the electrolyzer's operating point and ensuring that the system always operates under efficient and stable hydrogen production conditions.

[0031] Photothermal electrolysis cell 8: Integrates the photothermal interface evaporation process with the proton exchange membrane 14 electrolysis process into a single device. For example... Figure 2 As shown, its specific structure includes the following pathways from coastal water to hydrogen: Photothermal film 10: Located on the outside of the anode plate 17, with a flow channel 9 on the side away from the anode plate 17, and also close to the photothermal source 4. This film is a hydrophobic porous film with highly efficient light absorption and heat conversion characteristics.

[0032] Photothermal film 10 can be a carbon-based composite PTFE hydrophobic porous photothermal film, a plasma nanoparticle-modified PVDF hydrophobic porous photothermal film, or a commercially available photothermal film.

[0033] In this embodiment, a PVDF hydrophobic porous photothermal film is used as the substrate, and a fluorinated multi-walled carbon nanotube functional layer is composited through an intermediate adhesive layer.

[0034] When exposed to sunlight, the photothermal film 10 heats up rapidly, directly heating the seawater flowing over its surface and causing it to evaporate and produce pure water vapor. The water vapor can pass through the hydrophobic membrane pores 101, while liquid seawater and dissolved salts are completely blocked.

[0035] Air gap 11: Located on the inner side of the photothermal film 10, that is, the side facing the inside of the electrolytic cell, it provides a space for water vapor to diffuse and facilitates the discharge of oxygen generated by electrolysis.

[0036] The structure of the PEM electrolytic cell, from the side closest to the photothermal film 10 to the side furthest from the photothermal film 10, is as follows: Anode end plate 17: Located adjacent to air gap 11, it is the inlet end plate of the electrolytic cell and is connected to photovoltaic power generation unit 2.

[0037] Anode diffusion layer 12: Located inside the anode end plate 17, it is made of porous conductive material (such as titanium felt or titanium mesh) and is used to evenly distribute water vapor and conduct current. It plays a role in collecting current, separating water flow from air flow, and providing support, thereby further promoting the advancement of water vapor.

[0038] Anode catalyst layer 13: Supported IrO2 catalyst, which is the active site for the oxidation reaction of water molecules.

[0039] Proton exchange membrane 14: a perfluorosulfonic acid membrane located between the anode and cathode catalyst layers 13, allowing only protons (H+) to pass through. + Selective passage.

[0040] Cathode catalytic layer 15: Supported Pt / C catalyst (in this embodiment, a commercially available catalyst with a platinum-to-carbon ratio of 1:4 is selected), which is the active site for the reduction reaction of protons to generate hydrogen.

[0041] Cathode diffusion layer 16: It is attached to the outside of the cathode catalyst layer 15 and is also made of porous conductive material. It is used to collect the generated hydrogen, conduct current and provide mechanical support.

[0042] Cathode end plate 18: Located on the outermost side of the electrolytic cell, serving as the outlet end plate, and equipped with flow channel 9 for exporting the generated hydrogen gas.

[0043] The working process of a photothermal electrolysis cell is as follows: 1. Steam supply: The pure water vapor generated by the photothermal film passes through the photothermal film, diffuses through the air gap, and enters the anode diffusion layer through the channel of the anode end plate.

[0044] 2. Anodic oxidation reaction: Water vapor reaches the anodic catalyst layer through the anodic diffusion layer, and undergoes an electrochemical oxidation reaction under the action of IrO2 catalyst and external voltage. 2H₂O→O₂↑+4H + +4e - .

[0045] The generated oxygen passes through the anode diffusion layer and the anode end plate channel, and is discharged from the system through the air gap.

[0046] The generated protons migrate through the proton exchange membrane to the cathode under the drive of the electric field.

[0047] The generated electrons (e - The catalyst flows out from the surface of the anode and enters the external circuit, where electrons are transported to the cathode.

[0048] 3. Proton transmembrane migration: Protons pass through the proton exchange membrane and migrate from the anode side to the cathode side.

[0049] 4. Cathodic Reduction Reaction: Protons migrating to the cathode side reach the cathode catalyst layer. Simultaneously, electrons from the photovoltaic power generation unit pass through the cathode end plate and cathode diffusion layer to reach the cathode catalyst layer. On the Pt / C catalyst surface, protons and electrons combine to undergo a reduction reaction: 4H + +4e - →2H2↑ The generated hydrogen gas is collected through the cathode diffusion layer, discharged through the cathode end plate channel, and transported to the hydrogen collection tank.

[0050] The conversion relationship between current density and hydrogen production volume under standard conditions of 0℃ and 101.325 kPa is as follows: in, For hydrogen production volume, The effective reaction area of ​​the electrode plate. It is Faraday's constant. For time, This is the integral of the current density-time curve.

[0051] 5. Hydrogen collection: The generated hydrogen is collected through the cathode diffusion layer and led out to the hydrogen collection tank through the channel of the cathode end plate.

[0052] Example 2 This embodiment provides a method for producing hydrogen from seawater steam by photothermal film distillation coupled with photovoltaic electrolysis, implemented using the system provided in Embodiment 1, and including the following steps: (1) Seawater is transported to the seawater channel at the photothermal electrolysis cell by gravity through a high-level water tank.

[0053] (2) The photothermal film on the PEM electrolytic cell is irradiated by sunlight to generate heat to heat the seawater flowing through it. The water vapor generated by the evaporation of seawater enters the interior of the electrolytic cell through the photothermal film.

[0054] (3) Solar energy is converted into electrical energy using photovoltaic panels and the electrical energy is connected to the anode and cathode of the PEM electrolytic cell.

[0055] (4) Water vapor passes through the diffusion layer in sequence inside the electrolytic cell to reach the anode catalyst layer, where it undergoes an electrochemical reaction to decompose into oxygen and protons. The protons pass through the proton exchange membrane to reach the cathode catalyst layer, where a reduction reaction occurs to synthesize hydrogen. The hydrogen is then introduced into the hydrogen collection tank.

[0056] (5) The seawater that remains after passing through the photothermal film and has increased concentration flows into and returns to the high-level water tank by the power of water flow.

[0057] Example 3 This embodiment uses the system provided in Embodiment 1 and the method provided in Embodiment 2 to conduct an outdoor experiment.

[0058] Outdoor lighting conditions on that day Figure 3 As shown, measurements taken at the angle of the photovoltaic panel using an irradiance meter reflect the variation in light intensity over a given period. During this observation period, the light intensity exhibits fluctuating characteristics. Overall, the light intensity is not in a stable state but rather fluctuates within a considerable range.

[0059] Based on these lighting conditions, the energy transfer state in this embodiment is as follows: Figure 4As shown, although there are some fluctuations, the overall temperature remains within a relatively stable range, except for frequent and drastic fluctuations under lighting conditions (light intensity between 300-900 W / m² for approximately 0-250 minutes). 2 Under conditions of significant fluctuations (such as those caused by photovoltaic power output), the DC-DC converter can regulate and convert unstable DC power sources, such as photovoltaic output, to maintain a working voltage that consistently matches the electrolytic cell's rated operating voltage of 1.6–2.2V. This indicates that the electrolytic cell maintains effective output throughout this period. Its output results are as follows: Figure 5 As shown, Figure 5 The current load is the effective reaction area of ​​the cathode in the electrolytic cell, expressed in mA / cm². 2 This is a core characterizing parameter for the performance of hydrogen production through electrolysis. Meanwhile, Figure 5 The reaction data directly determine the hydrogen production: according to Faraday's law, the integral value of the current density is positively correlated with the hydrogen production; the higher the current density, the greater the hydrogen production per unit time. In this embodiment, the effective area S is 9 cm². 2 One hour before the experiment, the amount of hydrogen produced was measured. The theoretical hydrogen production in the first hour, calculated by the formula, was about 1.465 L, while the actual collection was 1.416 L. The results were close, thus verifying the correctness of the formula.

[0060] Therefore, this invention discloses a photothermal film distillation coupled photovoltaic electrolysis seawater steam hydrogen production system and method, which couples photovoltaic photothermal with seawater desalination-PEM electrolysis hydrogen production system, realizing the dual high-efficiency conversion of renewable energy solar energy "photo-electricity" and "photo-thermal", improving the energy utilization efficiency of the entire system, and obtaining high-purity energy hydrogen with only solar energy and seawater without the need for other external energy input.

[0061] The specific embodiments described above further illustrate the purpose, technical solution, and beneficial effects of the present invention. It should be understood that the above description is only a specific embodiment of the present invention and does not limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A system for hydrogen production from seawater vapor by photovoltaic electrolysis coupled with photothermal membrane distillation, characterized in that, It includes a material management unit, a photovoltaic power generation unit, a photovoltaic power generation monitoring unit, and a solar thermal electrolysis cell; The material management unit includes an elevated water tank and a hydrogen collection tank. The elevated water tank is used to store seawater and supply seawater to the photothermal electrolysis cell by gravity. The hydrogen collection tank is used to collect hydrogen generated by the photothermal electrolysis cell. The photovoltaic power generation unit is used to convert solar energy into electrical energy and to supply power to the photothermal electrolysis cell; The photovoltaic power generation monitoring unit is used to monitor the electrical output parameters of the photovoltaic power generation unit in real time; The photothermal electrolysis cell integrates a photothermal film and a PEM electrolysis cell. It is used to absorb solar energy and heat seawater from the high-level water tank to generate water vapor. At the same time, it uses the electrical energy provided by the photovoltaic power generation unit to electrolyze the generated water vapor to generate hydrogen and oxygen.

2. The system of claim 1, wherein the system further comprises a photovoltaic cell, wherein the photovoltaic cell is configured to generate electricity from the solar energy, and wherein the photovoltaic cell is configured to provide the electricity to the electrolyzer. The photothermal electrolysis cell includes an anode plate and a cathode plate. A photothermal film is disposed on the outer side of the anode plate, and a proton exchange membrane is disposed at the center of the anode plate and the cathode plate. A catalytic layer and a diffusion layer are symmetrically disposed at both ends of the proton exchange membrane. An air gap is formed between the photothermal film and the anode plate to allow water vapor to diffuse and oxygen to escape. A seawater channel is provided on the side of the photothermal film away from the anode plate.

3. The system of claim 2, wherein the system further comprises a photovoltaic cell, wherein the photovoltaic cell is configured to generate electricity from the solar energy, and wherein the photovoltaic cell is configured to provide the electricity to the electrolyzer. The photovoltaic power generation monitoring unit includes a current sensor, a voltage sensor, and a DC-DC converter. The anode plate and the cathode plate are both connected to the photovoltaic power generation unit. The current sensor and the DC-DC converter are sequentially arranged at the connection points between the anode plate, the cathode plate, and the photovoltaic power generation unit. The voltage sensor is electrically connected to both sides of the photothermal electrolysis cell.

4. The system of claim 1, wherein the system further comprises a photovoltaic cell. The material management unit also includes a circulation pipeline for transporting the remaining unevaporated seawater in the photothermal electrolysis cell back to the high-level water tank.

5. The system of claim 1, wherein the system further comprises a photovoltaic cell. The elevated water tank is positioned higher than the photothermal electrolysis cell.

6. The photothermal film distillation coupled with photovoltaic electrolysis seawater steam to produce hydrogen system according to claim 2, characterized in that, The photothermal film is a hydrophobic porous film with photothermal conversion function; The diffusion layer is any one of titanium mesh, titanium felt, or titanium foam; The catalyst layer includes an anode catalyst layer near the anode end plate and a cathode catalyst layer near the cathode end plate. The catalyst of the anode catalyst layer is IrO2, and the catalyst of the cathode catalyst layer is platinum / carbon. The proton exchange membrane is a perfluorosulfonic acid membrane.

7. The photothermal film distillation coupled with photovoltaic electrolysis seawater steam to produce hydrogen system according to claim 2, characterized in that, In the aforementioned photothermal film distillation coupled with photovoltaic electrolysis of seawater steam to produce hydrogen system, under standard conditions of 0℃ and 101.325 kPa, the conversion relationship between current density and hydrogen production volume is as follows: in, For hydrogen production volume, The effective reaction area of ​​the electrode plate. It is Faraday's constant. For time, This is the integral of the current density-time curve.

8. A method for producing hydrogen from seawater steam by photothermal film distillation coupled with photovoltaic electrolysis, characterized in that, The hydrogen production system, which uses photothermal film distillation coupled with photovoltaic electrolysis of seawater steam as described in any one of claims 1-7, includes the following steps: (1) Seawater is transported to the seawater channel at the photothermal electrolysis cell by gravity through an elevated water tank; (2) The photothermal film on the PEM electrolytic cell is irradiated by sunlight to generate heat to heat the flowing seawater. The water vapor generated by the evaporation of seawater passes through the photothermal film and enters the interior of the electrolytic cell. (3) Solar energy is converted into electrical energy using photovoltaic panels and the electrical energy is connected to the anode and cathode of the PEM electrolytic cell; (4) Water vapor passes through the diffusion layer in the electrolytic cell and reaches the anode catalyst layer in sequence. It undergoes an electrochemical reaction and decomposes into oxygen and protons. The protons pass through the proton exchange membrane and reach the cathode catalyst layer. A reduction reaction occurs in the cathode catalyst layer to synthesize hydrogen. The hydrogen is then introduced into the hydrogen collection tank. (5) The seawater that remains after passing through the photothermal film and has increased concentration flows into and returns to the high-level water tank by the power of water flow.

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