A series-connected solar-thermal-chemical coupled lunar surface resource utilization system and method

Abstract

This invention proposes a series-connected solar-thermal-chemical coupled lunar resource utilization system and method. The system mainly consists of a solar concentrator, a solar-thermal-chemical reactor, a lunar soil-based oxygen carrier material, a segmented temperature control system, a vacuum chamber, and a heat recovery system. The solar concentrator concentrates lunar sunlight to the solar-thermal-chemical reactor, enabling the lunar soil-based oxygen carrier material to undergo photocatalytic reduction and thermochemical reduction reactions. After the reduction reaction, the material undergoes an oxidation reaction with water to obtain hydrogen and oxygen. Under the control of the segmented temperature control system, photothermal coupling is achieved, thereby promoting the formation of oxygen vacancies in the material and enhancing the efficiency of solar-powered water splitting for oxygen and hydrogen production, thus realizing the acquisition and efficient utilization of lunar resources.

Description

Technical Field

[0001] This invention belongs to the field of solar energy utilization technology, specifically relating to a series-connected solar thermal-chemical coupled lunar surface resource utilization system and method. Background Technology

[0002] With the increasing maturity of space technology, humanity's desire to explore deep space has grown stronger. As the closest large natural celestial body to Earth, the Moon has become the first choice for humanity to achieve long-term survival and development of extraterrestrial bodies, holding significant research importance and rich utilization value for human space exploration. Landing on asteroids and establishing research or outpost bases to utilize asteroid resources has always been a research hotspot in human space exploration. Furthermore, with the increasing depletion of Earth's resources and the gradual exhaustion of some resources, the development and utilization of extraterrestrial resources has become a new high ground in technological competition.

[0003] The cost of lunar transport is far higher than that of low Earth orbit transport. Gravity and other space environmental factors increase the complexity and cost of missions. Furthermore, the extremely harsh environment on the lunar surface increases the difficulty of landing and return, ultimately resulting in lunar transport costs generally not falling below $30,000 / kg. Therefore, in-situ acquisition of basic resources is crucial in lunar resource development. Oxygen is a key material for the construction of future lunar bases and is also essential for ensuring the survival of astronauts on the lunar surface. Solar energy is the most readily available energy source in early development. The vacuum environment on the lunar surface reduces atmospheric reflection and absorption losses of solar radiation, resulting in a higher density of solar energy received on the lunar surface compared to Earth. However, solar-powered systems must possess long-term, large-scale energy storage technologies to cope with the prolonged lack of sunlight on the lunar surface.

[0004] Converting solar energy into chemical energy can fully utilize the advantages of lunar solar energy and solve the problem of long-term energy storage and transportation under conditions of no sunlight. Solar chemical energy storage technologies mainly include solar photocatalytic fuel production technology and solar thermochemical fuel production technology. Photocatalysis technology generates electrons on the catalyst surface and releases oxygen to complete a reduction reaction under sunlight excitation. Heat is then provided to allow oxygen vacancies in the material to combine with oxygen atoms in H2O, resulting in an oxidation reaction to produce hydrogen. A commonly used solar thermochemical fuel production technology is the "two-step" solar thermochemical cycle for water splitting to produce hydrogen and oxygen. The "two-step" thermochemical cycle consists of reduction and oxidation processes. During the reduction process, the metal oxide oxygen carrier material absorbs heat energy, decomposes, and produces oxygen. After the reduction reaction is complete, the reduced oxygen carrier material reacts with the introduced H2O to revert to a higher-valence metal oxide, simultaneously producing hydrogen.

[0005] The chemical reaction equations involved in the two processes are as follows:

[0006] Photocatalytic reduction reaction:

[0007] Oxidation reaction of photocatalytic materials: MO a-b +bH2O→MO a +bH2

[0008] Thermochemical reduction reaction:

[0009] Thermochemical oxidation reaction: MO X-Y +YH2O→MO X +YH2

[0010] Photocatalytic materials and thermochemically cyclic oxygen carriers include iron oxides, multi-metal-doped oxides, and non-stoichiometric materials such as cerium oxide, perovskite, and spinel. These non-stoichiometric materials do not completely lose oxygen during reduction reactions, and the number and morphology of the resulting oxygen vacancies affect their physicochemical properties. Therefore, in photocatalysis and thermochemical reduction reactions, the introduction and regulation of oxygen vacancies are commonly used to improve catalytic activity. However, the number of oxygen atoms lost by the oxygen carrier material during photocatalysis and thermochemical reduction reactions is not uniform. The overall oxygen vacancies after reduction are difficult to maintain at the optimal oxidation performance sites, leading to increased overall material requirements and ultimately affecting solar energy utilization efficiency. Summary of the Invention

[0011] In view of this, the present invention proposes a series-connected solar-thermal-chemical coupled lunar surface resource utilization system. This system directly utilizes lunar soil structure to sinter oxygen carrier materials, and delivers sunlight to the reactor through a solar concentrator according to the requirements of photocatalytic and thermochemical reactions, providing appropriate concentration ratio and concentration temperature. Based on existing technologies, it combines thermochemical reduction with photocatalytic reduction, and uses photocatalysis-assisted thermochemistry or thermochemistry-assisted photocatalysis to achieve dynamic regulation of oxygen vacancies in the material, thereby improving the redox performance of the material and ultimately improving the overall utilization efficiency of solar energy.

[0012] The technical solution adopted by this invention to solve the technical problem is:

[0013] A series-connected solar-thermal-chemical coupled lunar surface resource utilization system, characterized in that it specifically includes: a solar concentrator, a solar-thermal-chemical reactor, a lunar soil-based oxygen carrier material, a segmented temperature control system, a vacuum chamber, and a heat recovery system, wherein:

[0014] The solar concentrator is used to gather sunlight from the lunar surface. Its internal regulator can reduce the concentration power according to the reaction type to provide the light required for photocatalytic reduction reaction, and can also switch to the concentrator mode to provide sufficient heat for thermochemical reaction.

[0015] The solar photothermal chemical reactor is used to carry photocatalytic reduction, thermochemical reduction, and thermochemical oxidation reactions. The light-transmitting window of the solar photothermal chemical reactor allows the lunar soil-based oxygen carrier material to receive sunlight and undergo photocatalytic reduction to release oxygen. At the same time, it can withstand the working temperature of the thermochemical reduction reaction, allowing the lunar soil-based oxygen carrier material to undergo thermochemical reduction and decompose to release oxygen. After the photocatalytic reduction and thermochemical reduction reactions, H2O is introduced into the solar photothermal chemical reactor to react with the lunar soil-based oxygen carrier material to undergo thermochemical oxidation and release hydrogen. The lunar soil-based oxygen carrier material is re-oxidized and then participates in the photocatalytic reduction and thermochemical reduction reactions again.

[0016] The lunar soil-based oxygen carrier material is used to undergo photocatalytic reduction reaction under the excitation of solar light in photocatalytic reduction and thermochemical reduction reaction, and to absorb solar heat energy to decompose and release oxygen in thermochemical reduction reaction. After the photocatalytic reduction reaction and thermochemical reduction reaction are completed, it reacts with H2O introduced into the solar photothermal chemical reactor to release hydrogen. The lunar soil-based oxygen carrier material is re-oxidized and participates in the next photocatalytic reduction reaction and thermochemical reduction reaction.

[0017] The lunar soil-based oxygen carrier material uses lunar soil mineral particles as the basic raw material. After screening through processes such as gravity separation, electrostatic separation, magnetic separation, and flotation, metal oxide particles are obtained. After sintering at high temperature, a highly active and selective catalyst material is obtained. Specifically, it is mainly composed of ilmenite, which is relatively abundant in lunar soil, including iron oxides, polymetallic oxides, perovskite, and spinel composed of lunar soil mineral elements.

[0018] The segmented temperature control system determines the formation of oxygen vacancies in the lunar soil-based oxygen carrier material based on the oxygen generation detected by the oxygen analysis equipment. This is used to regulate the progress and termination of the photocatalytic reduction and thermochemical reduction reactions. Scheme I involves first performing photocatalytic reduction followed by thermochemical reduction, while Scheme II involves first performing thermochemical reduction followed by photocatalytic reduction. A total oxygen generation value is set as the control switching value in the segmented temperature control system. In Scheme I, once the total oxygen generation from the photocatalytic reduction reaches the control switching value, the solar concentrator is adjusted to focus high-temperature light to meet the requirements of the thermochemical reduction reaction. In Scheme II, once the total oxygen generation from the thermochemical reduction reaches the control switching value, light is provided to the solar photothermal reactor to prevent a significant temperature rise in the lunar soil-based oxygen carrier material. The control switching value is first calculated thermodynamically to determine the total oxygen generation rate when the rate of oxygen generation slows down during the photocatalytic and thermochemical reduction reactions. The control switching value can be any point between the start of the reaction and this total oxygen generation value, depending on the actual situation.

[0019] The vacuum chamber is used to draw oxygen generated in the photocatalytic reduction reaction and the thermochemical reduction reaction, as well as the H2O and hydrogen mixture at the outlet of the thermochemical oxidation reaction, with zero energy consumption by utilizing the vacuum environment on the lunar surface.

[0020] The heat recovery system is used to utilize the residual heat of the gas temporarily stored in the vacuum chamber to heat the raw material H2O in the photothermal chemical oxidation reaction, and to assist in the sintering and molding process of the lunar soil-based oxygen carrier material preparation process, thereby realizing the system's heat recovery and utilization.

[0021] Based on a series-connected solar-thermal-chemical coupled lunar surface resource utilization system, this invention proposes a series-connected solar-thermal-chemical coupled lunar surface resource utilization method, the specific content of which is as follows:

[0022] A solar concentrator gathers sunlight from the lunar surface to provide light and heat energy for photocatalytic and thermochemical reduction reactions, enabling in-situ water splitting on the lunar surface to produce oxygen and hydrogen. Under the control of a segmented temperature control system, the lunar soil-based oxygen carrier material in the solar photothermal chemical reactor first undergoes a photocatalytic reduction reaction using thermochemical-assisted photocatalysis scheme I. At this time, the surface temperature of the material rises to the range of 50℃-400℃ under sunlight. The progress of the photocatalytic reaction is judged by detecting the oxygen generation. After the oxygen generation rate slows down significantly, the solar concentrator switches to a concentrated heat collection mode, and the internal temperature of the solar photothermal chemical reactor rises to the range of 1000℃-2000℃. Through thermochemical reduction decomposition, the formation and stabilization of oxygen vacancies in the lunar soil-based oxygen carrier material are promoted. Finally, H2O is introduced into the solar photothermal chemical reactor to react with the lunar soil-based oxygen carrier material in a thermochemical oxidation reaction to produce hydrogen. In Scheme II using photocatalytic-assisted thermochemistry, the temperature is first raised to the range of the thermochemical reduction reaction. After reaching the control switching value, the temperature is gradually lowered to 50℃-400℃. The photocatalytic reduction reaction is used to control the active sites of oxygen vacancies in the oxygen carrier. Finally, the heat recovered during the cooling process is used to heat the raw materials required for the thermochemical oxidation reaction, completing the thermochemical oxidation reaction of the materials to produce hydrogen. Before the vacuum chamber starts working, it is connected to the vacuum environment on the lunar surface to maintain a vacuum environment inside the vacuum chamber. During the photocatalytic reduction reaction and the thermochemical reduction reaction, the valve connected to the reaction chamber of the solar photothermal chemical reactor is opened. The pressure difference between the reaction chamber of the solar photothermal chemical reactor and the vacuum chamber is used to extract the oxygen produced by the reduction reaction and reduce the oxygen partial pressure. In addition, after the thermochemical oxidation reaction is completed, the generated hydrogen and high-temperature water vapor are extracted from the solar photothermal chemical reactor using the vacuum chamber. The heat recovery system connected to the vacuum chamber initially completes the heat recovery of the high-temperature gas at the outlet of the solar photothermal chemical reactor.

[0023] The specific chemical equations involved in this method are as follows:

[0024] Option I:

[0025] (Photocatalysis, room temperature)

[0026] (Thermochemical regulation, 1400-1800℃)

[0027] MO x-z +zH2O→MO x +zH2 (oxidation reaction)

[0028] Option II:

[0029] (Photocatalysis, room temperature)

[0030] (Thermochemical regulation, 1400-1800℃)

[0031] MO x-z +zH2O→MO x +zH2 (oxidation reaction)

[0032] The beneficial effects of this invention are:

[0033] (1) By coupling photocatalytic reduction reaction with thermochemical reduction reaction, the oxygen vacancies of lunar soil-based oxygen carrier material are regulated, the oxidation activity of lunar soil-based oxygen carrier material is improved, the promoting effect of lunar soil material on reaction is enhanced, and the efficiency of solar water splitting to produce hydrogen and oxygen is ultimately improved.

[0034] (2) The hydrogen and oxygen produced during the reaction process are easy to store and transport, and can serve as an important resource supply method on the moon, enabling the in-situ utilization of lunar resources.

[0035] (2) Under the control of the segmented temperature control system, different heat energy utilization measures can be adopted for different schemes to reduce the heat energy loss caused by the large temperature difference switching between photocatalytic reduction reaction and thermochemical reduction reaction.

[0036] (3) By utilizing the vacuum environment on the lunar surface to collect gas, the large amount of energy consumed by traditional deoxygenation methods can be avoided, and irreversible losses can be reduced to a greater extent, thus improving the utilization rate of solar energy. Attached Figure Description

[0037] Figure 1 A schematic diagram of a series-connected solar-thermal-chemical coupled lunar surface resource utilization system provided by the present invention;

[0038] Figure 2 for Figure 1 A flowchart of a segmented temperature control system control scheme;

[0039] Figure 3 for Figure 1A flowchart of a segmented temperature control system control scheme;

[0040] Figure 4 for Figure 1 An enlarged schematic diagram of a vacuum chamber.

[0041] in, Figure 1 1-Solar concentrator, 2-Solar photothermal chemical reactor, 3-Solar soil-based oxygen carrier material, 4-Segmented temperature control system, 5-Vacuum chamber, 6-Heat recovery system; Figure 4 a-vacuum chamber, b-vacuum tank, c-heat exchanger. Detailed Implementation

[0042] The objectives and technical solutions of the present invention will be described in detail below with reference to the accompanying drawings and embodiments;

[0043] like Figure 1 As shown, Figure 1 This is a schematic diagram of a series-connected solar-thermal-chemical coupled lunar surface resource utilization system provided by the present invention. The system includes: a solar concentrator 1, a solar-thermal-chemical reactor 2, a lunar soil-based oxygen carrier material 3, a segmented temperature control system 4, a vacuum chamber 5, and a heat recovery system 6, wherein:

[0044] like Figure 1 As shown, the solar concentrator 1 is a dish or tower concentrator. Under the action of the automatic tracking system, it chases the sunlight on the lunar surface and focuses the sunlight on the lunar surface to the focal point. Through reflection, it provides light with a high concentration ratio and high concentration temperature to the solar photothermal chemical reactor 2, so that the lunar soil-based oxygen carrier material 3 undergoes a thermochemical reduction reaction.

[0045] When the solar concentrator 1 undergoes a photocatalytic reduction reaction inside the solar photothermal chemical reactor 2, it can reduce the concentration power and reflect the light beam into the solar photothermal chemical reactor 2, or use other low-magnification concentrators to provide illumination, or allow the solar photothermal chemical reactor 2 to directly receive sunlight.

[0046] The solar photothermal chemical reactor 2 is a hemispherical or cylindrical cavity with a double-layer shell structure. A vacuum environment is maintained in the shell sandwich to reduce heat loss from the cavity. At the same time, heat exchange pipes are arranged to recover the solid phase waste heat in the cavity during the cooling process of the reaction. A large amount of insulation material is filled between the inner wall of the reactor and the lunar soil-based oxygen carrier material 3 to further reduce irreversible losses from the equipment. The solar concentrator 1 enters the reactor through an adjustable quartz window. When the thermochemical reduction reaction occurs, the window narrows to allow light to enter while avoiding secondary radiation loss. When the photocatalytic reduction reaction occurs, the window widens to increase the light transmission area.

[0047] Lunar soil-based oxygen carrier material 3 is prepared from lunar soil as the basic raw material through processes such as screening, sintering, and additive manufacturing. Lunar soil-based oxygen carrier material 3 receives concentrated solar energy from solar concentrator 1. When the concentration temperature is 1000-2000℃, a thermochemical reduction reaction occurs to release oxygen. It can also undergo photocatalytic reduction under light conditions. H2O is introduced into solar photothermal chemical reactor 2 to react with the reduced lunar soil-based oxygen carrier material 3 to produce hydrogen. The oxidized lunar soil-based oxygen carrier material 3 then participates in photocatalytic reduction and thermochemical reduction reactions to achieve recycling.

[0048] The segmented temperature control system 4 determines the oxygen vacancy formation of the lunar soil-based oxygen carrier material 3 based on the oxygen generation detected by the oxygen analysis equipment, thereby regulating the progress and termination of the photocatalytic reduction reaction and the thermochemical reduction reaction. The segmented temperature control system 4 can realize two regulation strategies, including regulation scheme I, which first performs photocatalytic reduction and then regulates oxygen vacancy through thermochemical means, and regulation scheme II, which first performs thermochemical reduction and then optimizes the regulation of oxygen vacancy through photocatalysis.

[0049] Vacuum chamber 5 contains one or more vacuum chambers to collect oxygen from the reduction step outlet and a mixture of H2O and hydrogen from the oxidation step outlet. Oxygen analysis equipment detects the oxygen concentration generated by the photocatalytic reduction reaction and the thermochemical reduction reaction, and controls the opening and closing of the valves connecting the vacuum chamber and the solar photothermal chemical reactor. The vacuum chamber is also used to collect high-temperature water vapor and hydrogen from the outlet of the solar photothermal chemical reactor after the thermochemical oxidation reaction. The high-temperature oxygen from the photocatalytic reduction reaction and the thermochemical reduction reaction and the high-temperature mixture of the thermochemical oxidation reaction collected in the vacuum chamber exchange heat with H2O in the heat recovery system. The waste heat from the exchange assists in the sintering and molding of the lunar soil-based oxygen carrier material preparation stage. The valves connecting the vacuum chamber to the vacuum environment on the lunar surface ensure the restoration of the vacuum environment inside the vacuum chamber after the gas absorption process of the photocatalytic reduction reaction, the thermochemical reduction reaction, and the thermochemical oxidation reaction is completed.

[0050] The heat recovery system 6 heats the high-temperature gas collected in the vacuum chamber 5 to produce H2O for the oxidation reaction. At the same time, when implementing control scheme II, it recovers the residual heat in the reaction chamber of the lunar soil-based oxygen carrier material 3 and the solar photothermal chemical reactor 2 from the thermochemical reduction reaction for use in the subsequent oxidation step heating process. Finally, the various gases that have undergone heat exchange are stored or directly utilized.

[0051] Figure 2 and Figure 3The embodiment shown illustrates the specific operation of a segmented temperature control system. First, the control scheme type is selected in the control panel. The control scheme I operates as follows: First, the solar concentrator 1 is controlled to only concentrate light, causing the lunar soil-based oxygen carrier material to undergo a photocatalytic reduction reaction. After the photocatalytic reduction reaction, the material surface temperature does not exceed 400°C. Then, the solar concentrator 1 is controlled to provide sufficient concentration ratio and temperature for the thermochemical reduction reaction, further raising the temperature of the lunar soil-based oxygen carrier material 3 to 1000-2000°C. The thermochemical reduction reaction increases and stabilizes the number of oxygen vacancies in the reduced lunar soil-based oxygen carrier material. Finally, H2O is introduced for oxidation.

[0052] The control strategy of Scheme II is as follows: First, the solar concentrator 1 provides sufficient heat to the solar photothermal chemical reactor 2 to initiate a thermochemical reduction reaction. At this time, the surface temperature of the material is between 1000-2000℃. Subsequently, the solid waste heat is temporarily stored through the heat exchange pipes in the jacket of the solar photothermal chemical reactor 2, and the lunar soil-based oxygen carrier material is cooled to 50-400℃. The lunar soil-based oxygen carrier material 3 further increases oxygen vacancies during the photocatalytic reduction reaction under illumination. After the photocatalytic reduction reaction is completed, the solid waste heat stored in the heat exchange pipes in the jacket of the solar photothermal chemical reactor 2 is used to heat the reduced lunar soil-based oxygen carrier material 3. During the heating process, it undergoes an oxidation reaction with preheated H2O. Both control schemes use an oxygen analyzer to determine the progress of the photocatalytic reduction reaction and the thermochemical reduction reaction, and use the set total oxygen generation value as the control switching value between the photocatalytic reduction reaction and the thermochemical reduction reaction. When the control switching value is reached, the oxygen vacancy control stage begins. When the total oxygen generation is detected to be basically stable, it is determined that the photocatalytic reduction reaction and the thermochemical reduction reaction have ended.

[0053] Figure 4 The illustrated embodiment is... Figure 1The diagram shows an enlarged schematic of a vacuum chamber, including vacuum chamber a, its internal vacuum tank b, and heat exchanger c. Vacuum chamber a contains one or more vacuum tanks b. In the illustrated embodiment, the vacuum collector a has a double-layered outer shell, with an internal vacuum to prevent additional heat loss. Vacuum chamber a contains multiple sets of vacuum tanks b, which collect oxygen from the photocatalytic and thermochemical reduction reaction outlets and a mixture of high-temperature water vapor and hydrogen from the thermochemical oxidation reaction outlet. Vacuum tank b is connected to the photothermal chemical reactor via a valve, which is opened when the system controls the vacuum tank to collect gas. One end is connected to the heat exchange gas path of the heat recovery system, which is also opened when the vacuum tank collects gas. After the gas collection in vacuum chamber a is completed and the gas is transported to the heat recovery system, it is connected to the lunar surface vacuum environment to maintain the vacuum level inside the chamber. This allows the pressure difference between the chamber and the reactor chamber to force the gas inside the reactor into the vacuum tank chamber during system operation. Heat exchanger c has no heat exchange medium in its pipes during gas collection. After gas collection and transportation are completed, a heat exchange medium is introduced into it to recover heat from the vacuum tank and prevent residual heat.

[0054] Therefore, those skilled in the art should understand that the description of specific embodiments in this invention is not intended to limit the concept and scope of the invention. Any modifications and improvements to the technical solutions made without departing from the technical solutions of this invention will still fall within the protection scope of this invention.

Claims

1. A series-connected solar-thermal-chemical coupled lunar surface resource utilization system, characterized in that, The main components include: a solar concentrator (1), a solar photothermal chemical reactor (2), a lunar soil-based oxygen carrier material (3), a segmented temperature control system (4), a vacuum chamber (5), and a heat recovery system (6), among which: The solar concentrator (1) is used to concentrate sunlight on the lunar surface and increase the concentration temperature. The regulator inside the solar concentrator (1) can reduce the concentration power according to the reaction type to provide light to promote the occurrence of photocatalytic reduction reaction, and can also switch to a high concentration temperature mode to provide high temperature for thermochemical reduction reaction. The solar photothermal chemical reactor (2) is used to carry photocatalytic reduction reaction, thermochemical reduction reaction and thermochemical oxidation reaction. The light-transmitting window of the solar photothermal chemical reactor (2) allows the lunar soil-based oxygen carrier material (3) to receive sunlight and undergo photocatalytic reduction reaction to release oxygen. At the same time, it can withstand the working temperature of thermochemical reduction reaction to decompose the lunar soil-based oxygen carrier material (3) and release oxygen. After photocatalytic reduction reaction and thermochemical reduction reaction, H2O is introduced into the solar photothermal chemical reactor (2) to react with the lunar soil-based oxygen carrier material (3) to undergo thermochemical oxidation reaction to release hydrogen. The lunar soil-based oxygen carrier material (3) is re-oxidized and then participates in photocatalytic reduction reaction and thermochemical reduction reaction again for recycling. The lunar soil-based oxygen carrier material (3) is extracted from lunar soil in situ. The mineral fragments contained in the lunar soil include plagioclase, olivine, pyroxene, ilmenite, and spinel. The lunar soil is mined and then sintered at 1000-1800℃ after centrifugal screening, electrostatic screening and magnetic separation. The lunar soil-based oxygen carrier material (3) undergoes photocatalytic reduction reaction and thermochemical reduction reaction under the excitation of solar light. It absorbs solar heat energy and undergoes thermochemical reduction reaction to release oxygen. After the photocatalytic reduction reaction and thermochemical reduction reaction are completed, it undergoes thermochemical oxidation reaction with the introduced H2O to produce hydrogen. The segmented temperature control system (4) judges the photocatalytic reduction reaction and thermochemical reduction reaction process of lunar soil-based oxygen carrier material (3) based on the real-time oxygen generation detected by the oxygen analysis equipment. It is used to regulate the progress and end of the photocatalytic reduction reaction and thermochemical reduction reaction. The scheme of first performing the photocatalytic reduction reaction and then heating regulation is called Scheme I. The scheme of first performing the thermochemical reduction reaction and then regulating through the photocatalytic reduction reaction is called Scheme II. In Scheme I, after the total amount of oxygen generated by the photocatalytic reduction reaction reaches the regulation switching value, the solar concentrator (1) is adjusted to gather high-temperature light to meet the requirements of the thermochemical reduction reaction. In Scheme II, after the total amount of oxygen obtained by the thermochemical reduction reaction reaches the regulation switching value, light is provided to the solar photothermal chemical reactor (2) to avoid significant temperature rise of lunar soil-based oxygen carrier material (3). The vacuum chamber (5) and the heat recovery system (6) are combined. The vacuum chamber (5) is used to draw oxygen generated in the photocatalytic reduction reaction and thermochemical reduction reaction and H2O and hydrogen mixture at the outlet of the thermochemical oxidation reaction with zero energy consumption in the vacuum environment on the lunar surface. The heat recovery system (6) is used to utilize the residual heat of the gas temporarily stored in the vacuum chamber (5). The recovered heat is used to heat the H2O required for the thermochemical oxidation reaction and to assist the sintering of the lunar soil-based oxygen carrier material (3).

2. The series-connected solar-thermal-chemical coupled lunar surface resource utilization system according to claim 1, characterized in that, When the solar concentrator (1) is working, it gathers sunlight through a dish or tower concentrator to heat the lunar soil-based oxygen carrier material (3) at the focal point of the concentrator to carry out a thermochemical reduction reaction. When a photocatalytic reduction reaction is required, the solar concentrator (1) reduces the concentrating power and reflects the beam into the solar photothermal chemical reactor (2), or uses other low-power concentrators to provide illumination, or allows the solar photothermal chemical reactor (2) to directly receive sunlight.

3. The series-connected solar-thermal-chemical coupled lunar surface resource utilization system according to claim 1, characterized in that, The segmented temperature control system (4) has different control strategies depending on the order of coupling photocatalytic reduction reaction and thermochemical reduction reaction: Scheme I uses a segmented heating method to first control the solar concentrator (1) to provide only light so that the lunar soil-based oxygen carrier material (3) undergoes a photocatalytic reduction reaction to release oxygen until the photocatalytic reduction reaction is complete. At this time, the surface temperature of the material is raised to 50-400℃ due to solar radiation. Then, the solar concentrator (1) is controlled to increase the concentrating temperature range to 1000-2000℃ to further heat the material to the temperature at which the thermochemical reduction reaction occurs and stabilize the oxygen-air mixture. Oxygen vacancy generation; Scheme II first heats the lunar soil-based oxygen carrier material (3) to the thermochemical reduction reaction temperature to complete the thermochemical reduction reaction, and then cools the lunar soil-based oxygen carrier material (3) to 50-400℃ through a heat exchanger. In the photocatalytic reduction reaction, the formation of oxygen vacancy is regulated. After the photocatalytic reduction reaction and thermochemical reduction reaction stages are completed, the heat recovered by the heat recovery system (6) is used to gradually heat the reduced lunar soil-based oxygen carrier material (3). During the heating process, H2O is introduced into the solar photothermal chemical reactor (2) to complete the thermochemical oxidation reaction, and hydrogen is produced while realizing the circulation of the lunar soil-based oxygen carrier material (3).

4. A series-connected solar-thermal-chemical coupled lunar surface resource utilization system according to claim 1, characterized in that, Taking advantage of the lunar vacuum conditions, oxygen is collected during the photocatalytic reduction and thermochemical reduction processes using a vacuum chamber (5). The oxygen analysis equipment controls the opening and closing of the valves connecting the vacuum chamber (5) and the solar photothermal chemical reactor (2) to detect the oxygen concentration generated by the photocatalytic reduction and thermochemical reduction reactions. The vacuum chamber (5) is also used to collect the high-temperature water vapor and hydrogen gas at the outlet of the solar photothermal chemical reactor (2) after the thermochemical oxidation reaction is completed. The high-temperature oxygen and high-temperature mixed gas from the photocatalytic reduction and thermochemical reduction reactions collected by the vacuum chamber (5) are exchanged with H2O in the heat recovery system (6). The residual heat from the exchange assists in the sintering and molding of the lunar soil-based oxygen carrier material (3) during the preparation stage. The valves connecting the vacuum chamber (5) to the lunar surface vacuum environment ensure the restoration of the vacuum environment inside the vacuum chamber (5) after the absorption process of the photocatalytic reduction, thermochemical reduction, and thermochemical oxidation reactions.

5. A series-connected solar-thermal-chemical coupling method for utilizing lunar surface resources, applied to the system described in any one of claims 1-4, characterized in that, The implementation process of this method includes: The solar concentrator (1) gathers sunlight from the lunar surface to provide light and heat energy for the photocatalytic reduction and thermochemical reduction processes. Under the control of the segmented temperature control system (4), the lunar soil oxygen carrier material (3) in the solar photothermal chemical reactor (2) first undergoes a photocatalytic reduction reaction when performing scheme I of thermochemical reduction-assisted photocatalytic reduction reaction. At this time, the surface temperature of the material rises to the range of 50-400℃ under sunlight. The progress of the photocatalytic reduction reaction is judged by detecting the oxygen generation. After reaching the control switching value, the solar concentrator (1) further heats up the lunar soil-based oxygen carrier material (3), promoting the further formation and stabilization of oxygen vacancies in the oxygen carrier through the thermochemical reduction reaction. Finally, the lunar soil-based oxygen carrier material... Material (3) reacts with H2O to release hydrogen gas through a thermochemical oxidation reaction. When using Scheme II, which uses photocatalytic reduction reaction to assist thermochemical reduction, the solar concentrator (1) first heats the lunar soil-based oxygen carrier material (3) to the thermochemical reduction reaction temperature range of 1000-2000℃. After reaching the control switching value, the lunar soil-based oxygen carrier material (3) exchanges heat with the heat exchanger and cools down to the photocatalytic reduction reaction temperature. The photocatalytic reduction reaction is used to control the oxygen vacancy active sites of the oxygen carrier. The heat recovery system (6) recovers the waste heat from the photocatalytic reduction reaction and the thermochemical reduction reaction to heat the solar photothermal chemical reactor (2) and the lunar soil-based oxygen carrier material (3) inside. H2O is introduced into the solar photothermal chemical reactor (2) to complete the thermochemical oxidation reaction and achieve circulation. Before operation, the vacuum chamber (5) is connected to the vacuum environment on the lunar surface to achieve an absolute vacuum environment inside. During the photocatalytic reduction reaction and thermochemical reduction reaction, the valve connected to the environment is closed and the valve connected to the reaction chamber of the solar photothermal chemical reactor (2) is opened. The oxygen generated in the photocatalytic reduction reaction and thermochemical reduction reaction is extracted by using the pressure difference between the reaction chamber of the solar photothermal chemical reactor (2) and the vacuum chamber (5). At the same time, the heat recovery system (6) connected to the vacuum chamber (5) recovers oxygen heat. In the thermochemical oxidation reaction, the vacuum chamber (5) also uses the pressure difference between the solar photothermal chemical reactor (2) and the vacuum chamber (5) to collect the high-temperature water vapor and hydrogen at the outlet of the solar photothermal chemical reactor (2) after the thermochemical oxidation reaction is completed. The collected heat flow is exchanged with the reaction raw materials of the photocatalytic reduction reaction, thermochemical reduction reaction and thermochemical oxidation reaction.

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