A hydrogen production system based on solar energy

Abstract

The present invention discloses a hydrogen production system based on solar energy, comprising a first photocatalytic container and a second photocatalytic container, wherein an electron mediator is connected between the first photocatalytic container and the second photocatalytic container; a photocatalyst, a heat absorption structure, a heat conductive structure and a counter electrode are arranged in the first photocatalytic container and the second photocatalytic container, wherein the heat conductive structure is connected to the bottom of the heat absorption structure; a reaction liquid is contained in the photocatalytic container, and the liquid level is located above the heat absorption structure; a reduction reaction photocatalyst is arranged on the heat absorption structure and immersed in the reaction liquid; one end of the counter electrode is immersed in the reaction liquid; a thermoelectric conversion module for forming a hole flow and a thermoelectric conversion module for forming an electron flow are arranged below the heat conductive structure; the hot sides of the thermoelectric conversion modules are connected to the heat conductive structure, and the cold sides of the thermoelectric conversion modules are connected to the other end of the counter electrode, or connected to the photocatalyst.

Description

Technical Field

[0001] The present invention relates to the technical field of hydrogen production, and in particular to a hydrogen production system based on solar energy. Background Art

[0002] The global overuse of fossil fuels has caused a series of problems such as energy shortage, environmental pollution and the intensification of the greenhouse effect. In order to meet the needs of sustainable development and promote the development of a green economy, hydrogen energy, which has the advantages of being clean, efficient and sustainable, is receiving great attention, and a series of hydrogen production technologies have also been developed.

[0003] Photocatalytic hydrogen production using abundant solar energy in nature is considered to be one of the ideal hydrogen production technologies. Photocatalytic hydrogen production technology can be divided into one-step photocatalytic hydrogen production technology and two-step photocatalytic hydrogen production technology. Among them, the two-step photocatalytic hydrogen production technology absorbs sunlight through oxidation reaction / reduction reaction photocatalysts in two first photocatalytic containers to generate electrons and holes respectively, which then react with the reaction liquid to produce hydrogen and oxygen. Compared with the one-step photocatalytic hydrogen production technology, the two-step method has the advantages of automatic separation of hydrogen and oxygen and low requirements for semiconductor band gap.

[0004] However, the oxidation / reduction reaction photocatalysts discovered so far can only utilize short-wavelength sunlight, which has the problem of low efficiency and hinders large-scale commercial application; in addition, the photocatalytic hydrogen production system is also limited by the duration of sunlight, which restricts the production of hydrogen. Therefore, the existing technology still needs to be further improved. Summary of the invention

[0005] In view of the above problems, the present invention provides a solar-based hydrogen production system, comprising a first photocatalytic container and a second photocatalytic container, wherein an electron mediator is connected between the first photocatalytic container and the second photocatalytic container;

[0006] A reduction reaction photocatalyst, a first heat absorption structure, a first heat conducting structure, and a first pair of electrodes are arranged in the first photocatalytic container, the first heat conducting structure is connected to the bottom of the first heat absorption structure, the first photocatalytic container is filled with a reaction liquid, and the liquid level is located above the first heat absorption structure, the reduction reaction photocatalyst is arranged on the first heat absorption structure and immersed in the reaction liquid; one end of the first pair of electrodes is immersed in the reaction liquid; a first thermoelectric conversion module for forming a hole flow and a second thermoelectric conversion module for forming an electron flow are arranged below the first heat conducting structure; the hot sides of the first thermoelectric conversion module and the second thermoelectric conversion module are both in heat transfer contact with the first heat conducting structure, the hot sides of the first thermoelectric conversion module and the second thermoelectric conversion module are connected through a first current collector, the cold side of the first thermoelectric conversion module is connected to the other end of the first pair of electrodes, and the cold side of the second thermoelectric conversion module is connected to the reduction reaction photocatalyst;

[0007] An oxidation reaction photocatalyst, a second heat absorption structure, a second heat conductive structure, and a second pair of electrodes are arranged in the second photocatalytic container, the second heat conductive structure is arranged below the second heat absorption structure, the second photocatalytic container is filled with a reaction liquid, and the liquid level is located above the second heat absorption structure, the oxidation reaction photocatalyst is arranged on the second heat absorption structure and immersed in the reaction liquid; one end of the second pair of electrodes is immersed in the reaction liquid; a third thermoelectric conversion module for forming a hole flow and a fourth thermoelectric conversion module for forming an electron flow are arranged below the second heat conductive structure; the hot sides of the third thermoelectric conversion module and the fourth thermoelectric conversion module are both in heat transfer contact with the second heat conductive structure, the hot sides of the third thermoelectric conversion module and the fourth thermoelectric conversion module are electrically connected through a second current collector, the cold side of the fourth thermoelectric conversion module is connected to the other end of the second pair of electrodes, and the cold side of the third thermoelectric conversion module is connected to the oxidation reaction photocatalyst.

[0008] In some embodiments, a heat collector and a heat storage module are also included, and a first heat pipe filled with a heat-conducting fluid is provided in each of the heat collector and the heat storage module, and the first heat pipe flows through the heat collector and the heat-absorbing side of the heat storage module in sequence to form a closed cycle; the heat-releasing side of the heat storage module is in heat-transfer contact with the first heat-conducting structure, and the heat-releasing side of the heat storage module is in heat-transfer contact with the second heat-conducting structure.

[0009] A second heat-conducting pipe connected to the first heat-conducting structure is provided in the heat storage module to transfer the heat of the heat storage module to the first heat-conducting structure; a third heat-conducting pipe connected to the second heat-conducting structure is provided in the heat storage module to transfer the heat of the heat storage module to the second heat-conducting structure. The second heat-conducting pipe and the third heat-conducting pipe can be connected to each other.

[0010] In some embodiments, the first photocatalytic container and the second photocatalytic container are both provided with a liquid level control device for controlling the liquid level of the reaction liquid therein, and the liquid level control device includes a reaction liquid tank, a pump and a valve connected in sequence.

[0011] In some embodiments, the reduction reaction photocatalyst includes a plurality of reduction reaction photocatalyst modules uniformly distributed above the first heat absorption structure; the plurality of reduction reaction photocatalyst modules are arranged in parallel with each other, a first discharge plate is arranged between the reduction reaction photocatalyst module and the first heat absorption structure, and the first discharge plate is electrically connected to the cold side of the reduction reaction photocatalyst module and the second thermoelectric conversion module respectively;

[0012] The oxidation reaction photocatalyst includes a plurality of oxidation reaction photocatalyst modules evenly distributed above the second heat absorption structure; the plurality of oxidation reaction photocatalyst modules are arranged in parallel with each other, a second discharge plate is arranged between the oxidation reaction photocatalyst module and the second heat absorption structure, and the second discharge plate is electrically connected to the cold side of the oxidation reaction photocatalyst module and the third thermoelectric conversion module respectively.

[0013] In some embodiments, the hot sides of the first thermoelectric conversion module and the second thermoelectric conversion module are connected to the first thermal conductive structure through a current collector; the hot sides of the third thermoelectric conversion module and the fourth thermoelectric conversion module are connected to the second thermal conductive structure through a current collector.

[0014] In some embodiments, both sides of the first heat absorption structure and the first heat conducting structure, and both sides of the second heat absorption structure and the second heat conducting structure are provided with heat insulation structures.

[0015] In some embodiments, the first photocatalytic container is further provided with a hydrogen outlet, and the second photocatalytic container is further provided with an oxygen outlet.

[0016] In some embodiments, the first current collector, the second current collector, the first discharge plate, and the second discharge plate are made of metal materials.

[0017] In some embodiments, the first heat absorbing structure and / or the second heat absorbing structure are made of nanoporous heat absorbing material.

[0018] In some embodiments, the first thermoelectric conversion module and the third thermoelectric conversion module use P-type semiconductors, and the second thermoelectric conversion module and the fourth thermoelectric conversion module use N-type semiconductors.

[0019] In some embodiments, the collector is a trough collector or a tower collector.

[0020] In some embodiments, a phase change heat storage material is disposed in the heat storage module.

[0021] Due to the adoption of the above technical solution, the present invention has the following advantages and positive effects compared with the prior art:

[0022] 1. The solar energy-based hydrogen production system provided by the present invention, under light conditions, generates heat by absorbing a portion of long-wavelength sunlight that cannot be absorbed by the photocatalyst through the first heat absorption structure and the second heat absorption structure, thereby increasing the ambient temperature of the oxidation reaction / reduction reaction photocatalyst reaction and improving the catalytic efficiency.

[0023] 2. In the solar energy-based hydrogen production system provided by the present invention, through the arrangement of the collector and the heat storage module, under the condition of illumination, the collector and the heat storage module are used to collect solar energy and store it in the form of thermal energy, and a small part of the stored heat and a part of the heat generated by the heat absorption structure absorbing long-wavelength sunlight are transferred to the hot side of the thermoelectric conversion module, and a higher potential difference is generated through the temperature difference between the hot side and the cold side, and applied to the reduction reaction photocatalyst, the oxidation reaction photocatalyst and each pair of electrodes, effectively reducing the solar energy required to generate electrons / holes and improving the system efficiency; under the condition of no illumination, most of the heat stored in the heat storage module is transferred to the thermoelectric conversion module, so that the temperature of its hot side is higher, and at the same time, the temperature of its cold side is maintained at a lower temperature by means of the lower ambient temperature, so as to obtain a larger temperature difference, thereby forming a larger potential difference, and applying it to the reduction reaction photocatalyst, the oxidation reaction photocatalyst and each pair of electrodes, directly electrolyzing the reaction liquid to produce hydrogen and oxygen, realizing the preparation of hydrogen under the condition of no illumination, and improving the system production capacity. . BRIEF DESCRIPTION OF THE DRAWINGS

[0024] The above and other features and advantages of the present invention will be more clearly understood through the following detailed description in conjunction with the accompanying drawings, in which:

[0025] Figure 1 A schematic diagram of a solar-based hydrogen production system provided by the present invention;

[0026] Figure 2 for Figure 1 Schematic diagram of direction A in . DETAILED DESCRIPTION

[0027] The present invention will be described in more detail below with reference to the accompanying drawings showing embodiments of the present invention. However, the present invention may be implemented in many different forms and should not be construed as being limited to the embodiments set forth herein. Rather, these embodiments are set forth in order to achieve a full and complete disclosure and to enable those skilled in the art to fully understand the scope of the present invention. In these drawings, the sizes and relative sizes of layers and regions may be exaggerated for clarity.

[0028] Reference Figure 1-2 The present invention provides a solar-based hydrogen production system, comprising a first photocatalytic container 5 and a second photocatalytic container 20 , wherein an electron mediator 2 is connected between the first photocatalytic container 5 and the second photocatalytic container 20 .

[0029] Among them, the first photocatalytic container 5 is provided with a reduction reaction photocatalyst 3, a first heat absorption structure 7, a first heat conductive structure 12, and a first pair of electrodes 8. The first heat conductive structure 12 is arranged below the first heat absorption structure 7. The first photocatalytic container 5 is filled with a reaction liquid 4, and the liquid level is located above the first heat absorption structure 7. The reduction reaction photocatalyst 3 is arranged on the first heat absorption structure 7 and immersed in the reaction liquid 4; one end of the first pair of electrodes 8 is immersed in the reaction liquid 4, but does not contact the reduction reaction photocatalyst 3 and the first heat absorption structure 7; a first thermoelectric conversion module 16 for forming a hole flow and a second thermoelectric conversion module 15 for forming an electron flow are arranged below the first heat conductive structure 12; the hot sides of the first thermoelectric conversion module 16 and the second thermoelectric conversion module 15 are both in heat transfer contact with the first heat conductive structure 12, the hot sides of the first thermoelectric conversion module 16 and the second thermoelectric conversion module 15 are connected through the first current collector 29, the cold side of the first thermoelectric conversion module 16 is connected to the other end of the first pair of electrodes 8, and the cold side of the second thermoelectric conversion module 15 is connected to the reduction reaction photocatalyst 3.

[0030] The second photocatalytic container 20 is provided with an oxidation reaction photocatalyst 22, a second heat absorbing structure 24, a second heat conducting structure 25, and a second pair of electrodes 23. The second heat conducting structure 25 is provided below the second heat absorbing structure 24. The second photocatalytic container 20 is provided with a reaction liquid 21, and the liquid level is located above the second heat absorbing structure 24. The oxidation reaction photocatalyst 22 is provided on the second heat absorbing structure 24 and immersed in the reaction liquid 21. One end of the second pair of electrodes 23 is immersed in the reaction liquid 21, but does not contact the oxidation reaction photocatalyst 22 and the second heat absorbing structure 24. ; A third thermoelectric conversion module 27 for forming a hole flow and a fourth thermoelectric conversion module 26 for forming an electron flow are provided below the second heat-conducting structure 25; the hot sides of the third thermoelectric conversion module 27 and the fourth thermoelectric conversion module 26 are both connected to the second heat-conducting structure 25 in heat transfer contact, the hot sides of the third thermoelectric conversion module 27 and the fourth thermoelectric conversion module 26 are electrically connected through the second current collector 28, the cold side of the fourth thermoelectric conversion module 26 is connected to the other end of the second pair of electrodes 23, and the cold side of the third thermoelectric conversion module 27 is connected to the oxidation reaction photocatalyst 22.

[0031] During operation, the reduction reaction photocatalyst 3-reaction liquid 4-first pair of electrodes 8-first thermoelectric conversion module 16-second thermoelectric conversion module 15-reduction reaction photocatalyst 3 constitutes a half-reaction cycle for producing hydrogen; the oxidation reaction photocatalyst 22-fourth thermoelectric conversion module 27-third thermoelectric conversion module 26-second pair of electrodes 23-reaction liquid 21-oxidation reaction photocatalyst 22 constitutes a half-reaction cycle for producing oxygen.

[0032] Among them, during the photocatalytic hydrogen production process of the first photocatalytic container 5, when the reduction reaction photocatalyst 3 reacts with the reaction liquid 4, the reaction liquid loses electrons to produce hydrogen; during the photocatalytic oxygen production process of the second photocatalytic container 20, when the oxidation reaction photocatalyst 22 reacts with the reaction liquid 21, the reaction liquid obtains electrons to produce oxygen; and then, by means of the electron mediator 2 arranged between the first photocatalytic container 5 and the second photocatalytic container 20, the connection between the electrons and holes generated in the two half reactions is realized, thereby realizing a closed-loop reaction.

[0033] Specifically, sunlight is irradiated on the first photocatalytic container 5 and the second photocatalytic container 20; the first heat absorption structure 7 absorbs long-wavelength sunlight to generate heat, and transfers it from top to bottom through the first heat-conducting structure 12 to the hot side of the first thermoelectric conversion module 16 and the second thermoelectric conversion module 15 to maintain a relatively high temperature; the cold side of the first thermoelectric conversion module 16 and the second thermoelectric conversion module 15 is cooled by natural wind, and at this time, the ambient temperature is relatively high, and the temperature of the cold side of the first thermoelectric conversion module 16 and the second thermoelectric conversion module 15 is relatively high, so the temperature difference between the hot side and the cold side is relatively small, and the potential difference generated is relatively small, and the potential difference is applied to the reduction reaction photocatalyst 3; the reduction reaction photocatalyst 3 absorbs short-wavelength sunlight under the action of low potential to generate holes, and then reacts with the reaction liquid 4 to generate hydrogen;

[0034] At the same time, the second heat absorption structure 24 absorbs long-wavelength sunlight to generate heat, and transfers it from top to bottom through the second heat conductive structure 25 to the hot side of the third thermoelectric conversion module 27 and the fourth thermoelectric conversion module 26 to maintain a higher temperature; the cold side of the third thermoelectric conversion module 27 and the fourth thermoelectric conversion module 26 is cooled by natural wind. At this time, the ambient temperature is high, and the temperature of the cold side of the third thermoelectric conversion module 27 and the fourth thermoelectric conversion module 26 is high. Therefore, the temperature difference between the hot side and the cold side is small, and the potential difference generated is small. The potential difference is applied to the oxidation reaction photocatalyst 22; the oxidation reaction photocatalyst 22 absorbs short-wavelength sunlight under the action of low potential to generate electrons, which then react with the reaction liquid 21 to produce oxygen.

[0035] The present invention absorbs a portion of long-wavelength sunlight that cannot be absorbed by the photocatalyst to generate heat through the first heat absorption structure and the second heat absorption structure, thereby increasing the ambient temperature of the oxidation / reduction reaction photocatalyst reaction and improving the catalytic efficiency.

[0036] In this embodiment, combined with Figure 1 and Figure 2The reduction reaction photocatalyst 3 includes a plurality of reduction reaction photocatalyst modules uniformly distributed above the first heat absorption structure 7. The reduction reaction photocatalyst modules are in the shape of long strips extending in the longitudinal direction of the first heat absorption structure 7 and are arranged parallel to each other. The two ends of the plurality of reduction reaction photocatalyst modules are respectively connected and installed on the first heat absorption structure 7 through the first discharge plate 6. The first discharge plate 6 here realizes the connection and installation of the reduction reaction photocatalyst modules on the one hand, and is used to collect electrons on each reduction reaction photocatalyst module on the other hand. Furthermore, the first discharge plate 6 is also used to connect the reduction reaction photocatalyst module and the cold side of the second thermoelectric conversion module 15.

[0037] Similarly, the oxidation reaction photocatalyst 22 also includes a plurality of oxidation reaction photocatalyst modules uniformly distributed above the second heat absorption structure 24, the oxidation reaction photocatalyst modules are in the shape of long strips extending in the longitudinal direction of the second heat absorption structure 24, and are arranged parallel to each other; the two ends of the plurality of oxidation reaction photocatalyst modules are respectively connected and installed on the second heat absorption structure 24 through the second discharge plate, and the current collector here realizes the connection and installation of the reduction reaction photocatalyst module on the one hand, and is used to collect electrons on each oxidation reaction photocatalyst module on the other hand. Furthermore, the second discharge plate is also used to connect the oxidation reaction photocatalyst module and the cold side electrical connection of the third thermoelectric conversion module 27.

[0038] In this embodiment, the hot sides of the first thermoelectric conversion module 16 and the second thermoelectric conversion module 15 are connected to the first heat-conducting structure 12 through the first current collector 29; the hot sides of the third thermoelectric conversion module 27 and the fourth thermoelectric conversion module 26 are connected to the second heat-conducting structure 25 through the second current collector 28. The cold side of the first thermoelectric conversion module 16 is connected to the end of the first pair of electrodes 8 exposed to the reaction liquid through the third current collector 30 and the wire, the cold side of the second thermoelectric conversion module 15 is connected to the reduction reaction photocatalyst 3 through the fourth current collector 31 and the wire, the cold side of the third thermoelectric conversion module 27 is connected to the photoreaction catalyst 22 through the fifth current collector and the wire, and the cold side of the fourth thermoelectric conversion module 26 is connected to the second pair of electrodes 23 through the sixth current collector and the wire.

[0039] In this embodiment, the first heat absorbing structure 7 and the first heat conducting structure 12 are both provided with heat insulating structures 10, and similarly, the second heat absorbing structure 24 and the second heat conducting structure 25 are both provided with heat insulating structures. The heat insulating structures are used to prevent the heat of the first heat absorbing structure 7 and the first heat conducting structure 12, the second heat absorbing structure 24 and the second heat conducting structure 25 from dissipating to the left and right sides.

[0040] In this embodiment, the reduction reaction photocatalyst 3 and the oxidation reaction photocatalyst 22 are specifically semiconductor nanoparticles.

[0041] In this embodiment, the preferred first heat absorbing structure 7 and the second heat absorbing structure 24 are made of nanoporous heat absorbing materials, which have the characteristics of high light absorption rate and high thermal conductivity, and are conducive to transferring heat from top to bottom through the first heat conducting structure 12 and the second heat conducting structure 25 to the hot side of each thermoelectric conversion module below. At the same time, the nanoporous heat absorbing material has a hydrophobic property, so that the reaction liquid is only on the surface of the nanoporous heat absorbing material, thereby preventing the heat from being taken away by the reaction liquid.

[0042] Of course, in other embodiments, the specific materials of the first heat absorption structure 7 and the second heat absorption structure 24 can also be selected according to specific circumstances, as long as they have the characteristics of high light absorption rate and high thermal conductivity, and there is no limitation here.

[0043] In this embodiment, the first heat-conducting material 12 and the second heat-conducting structure 25 are preferably made of materials with high thermal conductivity, which can be selected according to specific circumstances and are not limited here.

[0044] In this embodiment, preferably, the first thermoelectric conversion module 16 and the third thermoelectric conversion module 27 use P-type semiconductors, and the second thermoelectric conversion module 15 and the fourth thermoelectric conversion module 26 use N-type semiconductors.

[0045] In this embodiment, preferably, each of the current collectors and each of the discharge point plates are made of metal material, which has the characteristic of high conductivity.

[0046] In this embodiment, refer to Figure 1 As shown in the figure, a hydrogen outlet 5 is also provided on the first photocatalytic container 5 and is located at the top of the first photocatalytic container 5, and is used for the hydrogen generated after the reduction reaction photocatalyst reacts with the reaction liquid 4 to be output from the hydrogen outlet 5; an oxygen outlet 19 is also provided on the second photocatalytic container 20 and is located at the top of the second photocatalytic container 20, and is used for the oxygen generated after the oxidation reaction photocatalyst reacts with the reaction liquid 21 to be output from the oxygen outlet 19.

[0047] In this embodiment, the first photocatalytic container 5 and the second photocatalytic container 20 are both provided with a liquid level control device for controlling the liquid level of the reaction liquid therein, which is used to maintain the liquid level of the reaction liquid slightly higher than the height of the reduction reaction photocatalyst 3 and the oxidation reaction photocatalyst 22, so as to reduce the attenuation of sunlight in the reaction liquid.

[0048] The following is a specific description taking the liquid level control device on the first photocatalytic container 5 as an example. Specifically, the liquid level control device 9 is connected to the first photocatalytic container 5, and is used to monitor the liquid level of the reaction liquid 4 in the first photocatalytic container 5; the liquid level control device 9 is also sequentially connected to a valve 11, a pump 13 and a reaction liquid tank 14; the reaction liquid tank 14 contains reaction liquid, and the liquid level control device 9 monitors the liquid level of the reaction liquid 4 in the first photocatalytic container 5, and as needed, controls the opening of the valve 11 and the pump 13 to replenish the reaction liquid in the reaction liquid tank 14 into the container, thereby ensuring that the reaction liquid level is slightly higher than the height of the reduction reaction photocatalyst 3.

[0049] Likewise, the second photocatalytic container 20 is also connected to a liquid level control device, a valve, a pump and a reaction liquid tank.

[0050] The reaction liquid is specifically water.

[0051] In this embodiment, preferably, the hydrogen production system further includes a heat collector 17 and a heat storage module 18. The heat collector 17 and the heat storage module 18 are both provided with a first heat pipe filled with a heat-conducting liquid, and the first heat pipe forms a closed cycle; the heat storage module 18 and the first heat-conducting structure 12 are provided with a second heat pipe filled with a heat-conducting liquid, and the heat storage module 18 and the second heat-conducting structure 25 are provided with a third heat pipe filled with a heat-conducting liquid, and the second heat pipe and the third heat pipe respectively form a closed cycle. When sunlight irradiates the heat collector 17, the heat of the heat collector 17 is transmitted to the heat storage module 18 through the first heat pipe and stored.

[0052] The heat collector 17 adopts trough-type heat collection, and the heat storage module 18 adopts a phase-change heat storage module.

[0053] Under light conditions, a small portion of the heat stored in the heat storage module 18 is transferred to the hot side of the second thermoelectric conversion module 15, the first thermoelectric conversion module 16, the third thermoelectric conversion module 27, and the fourth thermoelectric conversion module 26 to maintain a higher temperature;

[0054] Under no-light conditions, most of the heat stored in the heat storage module 18 is transferred to the hot side of the second thermoelectric conversion module 15 and the first thermoelectric conversion module 16 to maintain a higher temperature;

[0055] Under no-light conditions, the cold sides of the second thermoelectric conversion module 15, the first thermoelectric conversion module 16, the third thermoelectric conversion module 27, and the fourth thermoelectric conversion module 26 are cooled by natural wind. At this time, the ambient temperature is low, and the cold side temperatures of the second thermoelectric conversion module 15, the first thermoelectric conversion module 16, the third thermoelectric conversion module 27, and the fourth thermoelectric conversion module 26 are low. Due to the higher temperature on the hot side and the lower temperature on the cold side, the temperature difference is large, and the potential difference generated is large, which is applied to the reduction reaction photocatalyst and the oxidation reaction photocatalyst;

[0056] Under no light conditions, the reduction reaction photocatalyst and the oxidation reaction photocatalyst directly electrolyze the reaction liquid at high potential to produce hydrogen and oxygen.

[0057] In this embodiment, by setting up the collector 17 and the heat storage module 18, under the condition of light, the collector 17 and the heat storage module 18 are used to collect solar energy and store it in the form of thermal energy, and a small part of the stored heat and a part of the heat generated by the heat absorption structure absorbing long-wavelength sunlight are transferred to the hot side of the thermoelectric conversion module, and a potential difference is generated by the temperature difference between its hot side and cold side, and applied to the reduction reaction photocatalyst, the oxidation reaction photocatalyst and each pair of electrodes, so as to effectively reduce the solar energy required to generate electrons / holes and improve the system efficiency; under the condition of no light, most of the heat stored in the heat storage module is transferred to the thermoelectric conversion module to make the temperature of its hot side higher, and at the same time, the temperature of its cold side is maintained at a lower level by relying on the lower ambient temperature, so as to obtain a larger temperature difference, thereby forming a larger potential difference, and applying it to the reduction reaction photocatalyst, the oxidation reaction photocatalyst and each pair of electrodes, directly electrolyzing the reaction liquid to produce hydrogen and oxygen, so as to realize the preparation of hydrogen under the condition of no light and improve the system production capacity.

[0058] The working process of the present invention is further described below:

[0059] (1) Under light conditions

[0060] The first heat absorption structure 7 absorbs long-wavelength sunlight to generate heat, and transfers it from top to bottom through the first heat-conducting structure 12 to the hot side of the first thermoelectric conversion module 16 and the second thermoelectric conversion module 15 to maintain a relatively high temperature; the second heat absorption structure 24 absorbs long-wavelength sunlight to generate heat, and transfers it from top to bottom through the second heat-conducting structure 25 to the hot side of the third thermoelectric conversion module 27 and the fourth thermoelectric conversion module 26 to maintain a relatively high temperature; at the same time, a small portion of the heat stored in the heat storage module 18 is transferred to the hot sides of the second thermoelectric conversion module 15, the first thermoelectric conversion module 16, the third thermoelectric conversion module 27, and the fourth thermoelectric conversion module 26 to maintain a relatively high temperature;

[0061] The cold side of the first thermoelectric conversion module 16 and the second thermoelectric conversion module 15 is cooled by natural wind. At this time, the ambient temperature is high, and the temperature of the cold side of the first thermoelectric conversion module 16 and the second thermoelectric conversion module 15 is high. Therefore, the temperature difference between the hot side and the cold side is small, and the potential difference generated is small. This potential difference is applied to the reduction reaction photocatalyst 3; the reduction reaction photocatalyst 3 absorbs short-wavelength sunlight under the action of low potential to generate holes, and then reacts with the reaction liquid 4 to produce hydrogen. The cold side of the third thermoelectric conversion module 27 and the fourth thermoelectric conversion module 26 is cooled by natural wind. At this time, the ambient temperature is high, and the temperature of the cold side of the third thermoelectric conversion module 27 and the fourth thermoelectric conversion module 26 is high. Therefore, the temperature difference between the hot side and the cold side is small, and the potential difference generated is small. This potential difference is applied to the oxidation reaction photocatalyst 22; the oxidation reaction photocatalyst 22 absorbs short-wavelength sunlight under the action of low potential to generate electrons, and then reacts with the reaction liquid 21 to produce oxygen.

[0062] (2) Under no light conditions

[0063] The cold side of the second thermoelectric conversion module 15, the first thermoelectric conversion module 16, the third thermoelectric conversion module 27, and the fourth thermoelectric conversion module 26 is cooled by natural wind. At this time, the ambient temperature is low, and the cold side temperature of the second thermoelectric conversion module 15, the first thermoelectric conversion module 16, the third thermoelectric conversion module 27, and the fourth thermoelectric conversion module 26 is low. Due to the higher temperature of the hot side and the lower temperature of the cold side, the temperature difference is large, and the potential difference generated is large. The potential difference is applied to the reduction reaction photocatalyst and the oxidation reaction photocatalyst;

[0064] Under no light conditions, the reduction reaction photocatalyst and the oxidation reaction photocatalyst directly electrolyze the reaction liquid at high potential to produce hydrogen and oxygen.

[0065] In summary, the present invention designs a solar-based hydrogen production system to address the problems of low efficiency and limitation of sunlight exposure time in the current two-step photocatalytic hydrogen production system. Under light conditions, the oxidation reaction / reduction reaction photocatalyst absorbs short-wavelength sunlight to generate electrons and holes, and reacts with the reaction liquid to produce hydrogen and oxygen. The nanoporous heat-absorbing material under the photocatalyst absorbs long-wavelength sunlight to generate heat, part of which is transferred to the photocatalyst to increase the reaction temperature to improve the catalytic efficiency, and the other part is transferred to the hot side of the thermoelectric conversion material through the heat-conducting material. The temperature difference between the hot side and the cold side generates a potential difference, which is then applied to the photocatalyst and the counter electrode to reduce the energy required to generate electrons / holes and improve the efficiency of the hydrogen production system. At the same time, the trough collector absorbs The heat generated by the sunlight is stored in the phase change heat storage module, and a small part of the stored heat is transferred to the hot side of the thermoelectric conversion material to maintain a certain temperature difference between the hot and cold sides, ensuring the generation of a potential difference. Under no-light conditions, most of the heat stored in the phase change heat storage module is transferred to the hot side of the thermoelectric conversion material, making the hot side temperature higher. At the same time, the low ambient temperature under no-light conditions is used to maintain a lower temperature on the cold side of the thermoelectric conversion material, thereby generating a larger potential difference. The potential difference is also applied to the photocatalyst and the counter electrode, and the electrolysis reaction liquid produces hydrogen and oxygen, making full use of solar energy and increasing the system's production capacity.

[0066] Those skilled in the art will appreciate that the present invention can be implemented in many other specific forms without departing from its own spirit or scope. Although the implementation of the present invention has been described, it should be understood that the present invention should not be limited to these embodiments, and those skilled in the art can make changes and modifications within the spirit and scope of the present invention as defined by the appended claims.

Claims

1. A solar-based hydrogen production system, characterized in that: It comprises a first photocatalytic container and a second photocatalytic container, wherein an electron mediator is connected between the first photocatalytic container and the second photocatalytic container; A reduction reaction photocatalyst, a first heat absorption structure, a first heat conducting structure, and a first pair of electrodes are arranged in the first photocatalytic container, the first heat conducting structure is connected to the bottom of the first heat absorption structure, the first photocatalytic container is filled with a reaction liquid, and the liquid level is located above the first heat absorption structure, the reduction reaction photocatalyst is arranged on the first heat absorption structure and immersed in the reaction liquid; one end of the first pair of electrodes is immersed in the reaction liquid; a first thermoelectric conversion module for forming a hole flow and a second thermoelectric conversion module for forming an electron flow are arranged below the first heat conducting structure; the hot sides of the first thermoelectric conversion module and the second thermoelectric conversion module are both in heat transfer contact with the first heat conducting structure, the hot sides of the first thermoelectric conversion module and the second thermoelectric conversion module are connected through a first current collector, the cold side of the first thermoelectric conversion module is connected to the other end of the first pair of electrodes, and the cold side of the second thermoelectric conversion module is connected to the reduction reaction photocatalyst; The second photocatalytic container is provided with an oxidation reaction photocatalyst, a second heat absorption structure, a second heat conductive structure, and a second pair of electrodes, the second heat conductive structure is provided below the second heat absorption structure, the second photocatalytic container is filled with a reaction liquid, and the liquid level is located above the second heat absorption structure, the oxidation reaction photocatalyst is provided on the second heat absorption structure and immersed in the reaction liquid; one end of the second pair of electrodes is immersed in the reaction liquid; a third thermoelectric conversion module for forming a hole flow and a fourth thermoelectric conversion module for forming an electron flow are provided below the second heat conductive structure; the hot sides of the third thermoelectric conversion module and the fourth thermoelectric conversion module are both in heat transfer contact with the second heat conductive structure, the hot sides of the third thermoelectric conversion module and the fourth thermoelectric conversion module are electrically connected through a second current collector, the cold side of the fourth thermoelectric conversion module is connected to the other end of the second pair of electrodes, and the cold side of the third thermoelectric conversion module is connected to the oxidation reaction photocatalyst; It also includes a heat collector and a heat storage module. Sunlight irradiates the heat collector, and the heat of the heat collector is transferred to the heat storage module for storage. The heat release side of the heat storage module is in heat transfer contact with both the first heat conductive structure and the second heat conductive structure.

2. The solar-based hydrogen production system according to claim 1, characterized in that: The heat collector and the heat storage module are both provided with a first heat conduction pipe filled with heat conduction fluid, and the first heat conduction pipe flows through the heat collector and the heat absorption side of the heat storage module in sequence to form a closed cycle.

3. The solar-based hydrogen production system according to claim 1, characterized in that: The first photocatalytic container and the second photocatalytic container are both provided with a liquid level control device for controlling the liquid level of the reaction liquid therein, and the liquid level control device comprises a reaction liquid tank, a pump and a valve which are connected in sequence.

4. The solar-based hydrogen production system according to claim 1, characterized in that: The reduction reaction photocatalyst comprises a plurality of reduction reaction photocatalyst modules uniformly distributed above the first heat absorption structure; the plurality of reduction reaction photocatalyst modules are arranged in parallel with each other, a first discharge plate is arranged between the reduction reaction photocatalyst module and the first heat absorption structure, and the first discharge plate is electrically connected to the cold side of the reduction reaction photocatalyst module and the second thermoelectric conversion module respectively; The oxidation reaction photocatalyst includes a plurality of oxidation reaction photocatalyst modules evenly distributed above the second heat absorption structure; the plurality of oxidation reaction photocatalyst modules are arranged in parallel with each other, a second discharge plate is arranged between the oxidation reaction photocatalyst module and the second heat absorption structure, and the second discharge plate is electrically connected to the cold side of the oxidation reaction photocatalyst module and the third thermoelectric conversion module respectively.

5. The solar-based hydrogen production system according to claim 1, characterized in that: Both sides of the first heat absorbing structure and the first heat conducting structure, and both sides of the second heat absorbing structure and the second heat conducting structure are provided with heat insulating structures.

6. The solar-based hydrogen production system according to claim 1, characterized in that: The first photocatalytic container is also provided with a hydrogen outlet, and the second photocatalytic container is also provided with an oxygen outlet.

7. The solar-based hydrogen production system according to claim 1, characterized in that: The first heat absorbing structure and / or the second heat absorbing structure adopts nanoporous heat absorbing material.

8. The solar-based hydrogen production system according to claim 1, characterized in that: The first thermoelectric conversion module and the third thermoelectric conversion module use P-type semiconductors, and the second thermoelectric conversion module and the fourth thermoelectric conversion module use N-type semiconductors.

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