JP6805307B2 - How to operate the chemical reactor - Google Patents

Description

The embodiment relates to a method of operating a chemical reactor.

Renewable energy is increasing rapidly from the viewpoint of energy problems and environmental problems. In particular, in the EU, there are countries such as Sweden where renewable energy (renewable energy) accounts for 50% of energy.

By the way, since power consumption (electrical energy) constantly fluctuates depending on human living behavior, the balance between supply and demand becomes poor. When nuclear energy whose output is difficult to adjust and irregular natural energy are combined in order to supplement the power consumption, there is a concern that the generation of surplus power will increase because it cannot be adjusted to the amount of power consumption. As renewable energy increases in the future, there is a limit to adjusting the output with thermal energy.

It is conceivable to transmit this surplus electricity to areas where electricity is insufficient, but problems such as energy loss and cost due to transmission will occur. Countermeasures currently being taken to deal with such problems include pumping water by pumped storage power generation and storing electricity by storage batteries. However, there is a problem that the land suitable for installing a dam capable of pumped storage power generation is limited and the cost of storage batteries is high.

Thus, electrical energy has problems with storage and transmission. On the other hand, an artificial photosynthesis system has been proposed as a renewable energy that can be stored and transported.

Artificial photosynthesis is a technology that produces chemical fuel (chemical energy) using light energy like plants. Plants use a system called the Z scheme that excites light energy in two stages. As a result, plants use solar energy to oxidize water to obtain electrons and reduce carbon dioxide to synthesize cellulose and sugars. In artificial photosynthesis, an artificial photochemical reaction enables the photosynthetic reaction of this plant.

In Patent Document 1, a carbon dioxide (CO ₂ ) reduction catalyst is provided on the surface of the photocatalyst. Then, this CO ₂ reduction catalyst is connected to another photocatalyst via an electric wire. Another photocatalyst obtains an electric potential by light energy. CO ₂ reduction catalyst, through an electric wire to obtain a reduction potential from another photocatalyst, by reducing CO ₂ to produce formic acid. As described above, in Patent Document 1, two-stage excitation is used in order to obtain the potential required for reducing CO _{2 with} a photocatalyst using visible light. However, the conversion efficiency from sunlight to chemical energy is as low as 0.04%. This is due to the low energy efficiency of the photocatalyst excited by visible light.

In Patent Document 2, a configuration is considered in which a silicon solar cell is used to obtain a reaction potential, and catalysts are provided on both sides thereof to cause a reaction. Non-Patent Document 1, by using a configuration of repeating silicon solar cells in order to obtain a potential of the reaction, is subjected to electrolytic reaction of water (H 2 _O) by providing a catalyst on both surfaces thereof. The conversion efficiency from solar energy to chemical energy in these is as high as 4.7%.

However, even this artificial photosynthesis system does not exceed the solar energy conversion efficiency of the solar cell. In other words, since the electromotive force is obtained by charge separation by the solar cell, it is impossible to exceed the solar energy conversion efficiency of the solar cell.

Therefore, these artificial photosynthesis systems function effectively when there is surplus power, but do not function effectively when there is insufficient power. That is, in the case of power shortage, rather than converting solar energy into chemical energy by these artificial photosynthesis systems and converting this chemical energy into electrical energy, the solar cell is used to directly convert solar energy into electrical energy. It is more efficient to convert it to. Therefore, when there is a power shortage, it is more efficient to generate electrical energy using a solar cell than to generate chemical energy using an artificial photosynthesis system.

It is conceivable to install both an artificial photosynthesis system and a solar cell in order to solve the problems both when there is surplus power and when there is insufficient power. However, installing an artificial photosynthesis system and a solar cell requires at least twice the installation area.

Further, when there is surplus power and the solar energy is small, there is a method of converting electrical energy into chemical energy by a normal electrolytic system using a power source, in addition to the artificial photosynthesis system. However, there are problems such as the connection between the solar cell and the electrolytic system and the operation of the device so as to follow the unstable natural energy.

As described above, there is no integrated device in which the artificial photosynthesis system, the solar cell, and the electrolysis system operate appropriately so that the energy conversion efficiency becomes high depending on the conditions such as the presence / absence of surplus power and the presence / absence of solar energy. ..

Japanese Unexamined Patent Publication No. 2011-094194 Japanese Unexamined Patent Publication No. 10-2900017

S. Y. Reece, et al., Science. Vol.334. Pp.645 (2011)

Provided is an operation method of an integrated chemical reaction device that appropriately operates as an artificial photosynthesis system, a solar cell, or an electrolytic system so that the energy conversion efficiency becomes high according to various conditions.

The operation method of the chemical reaction device according to the present embodiment is an operation method of the chemical reaction device electrically connected to a power demand unit that stores or consumes electric power and an external power source that supplies electric power to the power demand unit. In
Among the electric power supplied from the external power source to the electric power demand unit, the first step of confirming the presence or absence of surplus electric power exceeding the demand of the electric power demand unit, and
The second step to check for the presence of solar energy,
Equipped with
In the first step, when there is no surplus power, the amount of the electrolytic solution in the electrolytic cell is controlled so that at least one electrode in the electrolytic cell is not immersed in the electrolytic cell, and the photovoltaic layer. It functions as a first system that supplies electric power to the electric power demand unit through the electrode by the electromotive force in the above .
If there is surplus power in the first step, the process proceeds to the second step.
In the second step, when there is no solar energy, the amount of the electrolytic cell in the electrolytic cell is controlled so that the electrode in the electrolytic cell is immersed in the electrolytic cell, so that the surplus power is generated. To function as a second system that causes an oxidation-reduction reaction in the electrolytic solution in contact with the electrode .
In the second step, when the solar energy is present, the amount of the electrolytic solution in the electrolytic cell is controlled so that the electrode in the electrolytic cell is immersed in the electrolytic cell , and the light is generated. It functions as a third system that causes an oxidation-reduction reaction in the electrolytic solution in contact with the electrode by the electromotive force of the power layer.

The schematic block diagram which shows the structural example of the chemical reaction apparatus which concerns on 1st Embodiment. The figure which shows the operation of the artificial photosynthesis system of the chemical reaction apparatus which concerns on 1st Embodiment. The figure which shows the operation of the electrolytic system of the chemical reaction apparatus which concerns on 1st Embodiment. The figure which shows the solar cell operation of the chemical reaction apparatus which concerns on 1st Embodiment. The figure which shows the modification of the solar cell operation of the chemical reaction apparatus which concerns on 1st Embodiment. The flowchart which shows the operation in the chemical reaction apparatus which concerns on 1st Embodiment. The schematic block diagram which shows the structure of the 1st modification of the chemical reaction apparatus which concerns on 1st Embodiment. The schematic block diagram which shows the structure of the 2nd modification of the chemical reaction apparatus which concerns on 1st Embodiment. The schematic block diagram which shows the structural example of the chemical reaction apparatus which concerns on 2nd Embodiment. The figure which shows the operation of the artificial photosynthesis system of the chemical reaction apparatus which concerns on 2nd Embodiment. The figure which shows the operation of the electrolytic system of the chemical reaction apparatus which concerns on 2nd Embodiment. The figure which shows the solar cell operation of the chemical reaction apparatus which concerns on 2nd Embodiment. The figure which shows the modification of the solar cell operation of the chemical reaction apparatus which concerns on 2nd Embodiment. The schematic block diagram which shows the structure of the 1st modification of the chemical reaction apparatus which concerns on 2nd Embodiment. The schematic block diagram which shows the structure of the 2nd modification of the chemical reaction apparatus which concerns on 2nd Embodiment. The schematic block diagram which shows the structural example of the chemical reaction apparatus which concerns on 3rd Embodiment. The figure which shows the operation of the artificial photosynthesis system of the chemical reaction apparatus which concerns on 3rd Embodiment. The figure which shows the operation of the electrolytic system of the chemical reaction apparatus which concerns on 3rd Embodiment. The figure which shows the solar cell operation of the chemical reaction apparatus which concerns on 3rd Embodiment. The figure which shows the modification of the solar cell operation of the chemical reaction apparatus which concerns on 3rd Embodiment. The schematic block diagram which shows the structure of the 1st modification of the chemical reaction apparatus which concerns on 3rd Embodiment.

This embodiment will be described below with reference to the drawings. In the drawings, the same parts are designated by the same reference numerals. In addition, duplicate explanations will be given as necessary.

1. 1. First Embodiment The chemical reaction apparatus according to the first embodiment will be described below with reference to FIGS. 1 to 8.

In the chemical reaction apparatus according to the first embodiment, the laminated body 10 including the first electrode 16, the photovoltaic layer 15, and the second electrode 11, the electrolytic cell 21 accommodating the laminated body 10, and the laminated body 10 It is composed of an external power supply 32 that can be electrically connected or disconnected and a power demand unit 34. As a result, the chemical reactor functions as an electrolytic system by electrically connecting the laminate 10 and the external power supply 32, and as a solar cell by electrically connecting the laminate 10 and the power demand unit 34. It functions and can function as an artificial photosynthesis system by electrically shutting off the laminate 10, the external power supply 32, and the power demand unit 34. Therefore, it is possible to provide an integrated chemical reaction apparatus that operates appropriately according to various conditions. The first embodiment will be described in detail below.

1-1. Configuration of the First Embodiment FIG. 1 is a schematic configuration diagram showing a configuration example of a chemical reaction apparatus according to the first embodiment. In addition, in FIG. 1, the laminated body 10 and the electrolytic cell 21 show the cross-sectional structure thereof.

As shown in FIG. 1, the chemical reaction apparatus according to the first embodiment includes a laminate 10, an electrolytic cell 21, an external power supply 32, a power demand unit 34, a switching element control unit 41, and an electrolytic solution control unit 61. ..

The electrolytic cell 21 houses the laminated body 10 inside. Further, the electrolytic cell 21 houses the electrolytic solution 23 so as to immerse the laminated body 10. The electrolytic solution 23 is, for example, a solution containing H ₂ O. Such solutions include but are intended to include any electrolyte, it is desirable is to promote the oxidation reaction of H 2 _O. The electrolytic solution 23 is, for example, a solution containing CO ₂ . The upper surface of the electrolytic cell 21 is provided with a window portion made of, for example, glass or acrylic, which has high light transmittance. The irradiation light is emitted from above the electrolytic cell 21. The laminated body 10 undergoes a redox reaction by this irradiation light.

Further, a pipe 22 is connected to the electrolytic cell 21. The pipe 22 injects the electrolytic solution 23 into the electrolytic cell 21, or discharges the electrolytic solution 23 from the electrolytic cell 21.

The electrolytic solution control unit 61 controls the electrolytic solution 23 in the electrolytic cell 21. More specifically, the electrolytic solution control unit 61 measures the amount of the electrolytic solution 23 in the electrolytic cell 21 and controls the injection and discharge of the electrolytic solution 23 through the pipe 22. As a result, the electrolytic solution control unit 61 fills the electrolytic cell 21 with the electrolytic solution 23 so that a sufficient electrolytic reaction occurs when used as an artificial photosynthesis system and an electrolytic system. Further, when used as a solar cell, the electrolytic solution control unit 61 discharges the electrolytic solution 23 from the electrolytic cell 21 so that electricity does not flow into the electrolytic cell 23, and fills the electrolytic cell 21 with air.

The laminate 10 has a first electrode 16, a photovoltaic layer 15, a second electrode 11, a first catalyst 17, and a second catalyst 18. The laminated body 10 has a flat plate shape that extends in a plane, and is sequentially formed with the second electrode 11 as a base material (substrate). Here, the light irradiation side will be described as the front surface (upper surface), and the opposite side of the light irradiation side will be described as the back surface (lower surface).

The second electrode 11 has conductivity. Further, the second electrode 11 is provided to support the laminated body 41 and increase its mechanical strength. The second electrode 11 is composed of, for example, a metal plate such as Cu, Al, Ti, Ni, Fe, or Ag, or an alloy plate containing at least one of them, such as SUS. Further, the second electrode 11 may be made of a conductive resin or the like. Further, the second electrode 11 may be composed of a semiconductor substrate such as Si or Ge, or an ion exchange membrane.

The photovoltaic layer 15 is formed on the second electrode 11 (on the surface (on the upper surface)). The photovoltaic layer 15 is composed of a first photovoltaic layer 12, a second photovoltaic layer 13, and a third photovoltaic layer 14.

The first photovoltaic layer 12, the second photovoltaic layer 13, and the third photovoltaic layer 14 are solar cells using pin-bonded semiconductors, and have different light absorption wavelengths. By stacking these in a plane, the photovoltaic layer 15 can absorb light having a wide wavelength of sunlight, and the solar energy can be used more efficiently. Further, since each photovoltaic layer is connected in series, a high open circuit voltage can be obtained.

More specifically, the first photovoltaic layer 12 is an n-type amorphous silicon (a-Si) layer formed on the second electrode 11 and formed in order from the lower side, for example, an intrinsic amorphous layer. It is composed of a silicon germanium (a-SiGe) layer and a p-type microcrystalline silicon (μc-Si) layer. Here, the a-SiGe layer is a layer that absorbs light in a long wavelength region of about 700 nm. That is, in the first photovoltaic layer 12, charge separation occurs due to the light energy in the long wavelength region.

Further, the second photovoltaic layer 13 is formed on the first photovoltaic layer 12, for example, an n-type a-Si layer formed in order from the lower side, an intrinsic a-SiGe layer, and an intrinsic a-SiGe layer. It is composed of a p-type μc-Si layer. Here, the a-SiGe layer is a layer that absorbs light in an intermediate wavelength region of about 600 nm. That is, in the second photovoltaic layer 13, charge separation occurs due to the light energy in the intermediate wavelength region.

Further, the third photovoltaic layer 14 is formed on the second photovoltaic layer 13, for example, an n-type a-Si layer formed in order from the lower side, an intrinsic a-Si layer, and an intrinsic a-Si layer. It is composed of a p-type μc-Si layer. Here, the a-Si layer is a layer that absorbs light in a short wavelength region of about 400 nm. That is, in the third photovoltaic layer 14, charge separation occurs due to the light energy in the short wavelength region.

As described above, in the photovoltaic layer 15, charge separation occurs due to the light in each wavelength region. That is, holes are separated on the anode side (front surface side) and electrons are separated on the cathode side (back surface side). As a result, the photovoltaic layer 15 generates an electromotive force.

The first electrode 16 is formed on the p-type semiconductor layer (p-type μc—Si layer) of the photovoltaic layer 15. Therefore, it is desirable that the first electrode 16 is made of a material capable of ohmic contact with the p-type semiconductor layer. The first electrode is composed of, for example, a metal such as Ag, Au, Al, or Cu, or an alloy containing at least one of them. Further, the first electrode 16 may be made of a transparent conductive oxide such as ITO, ZnO, FTO, AZO, or ATO. Further, the first electrode 16 has, for example, a structure in which a metal and a transparent conductive oxide are laminated, a structure in which a metal and another conductive material are composited, or a structure in which a transparent conductive oxide and another conductive material are composited. It may be composed of the above-mentioned structure.

Further, in this example, the irradiation light passes through the first electrode 16 and reaches the photovoltaic layer 15. Therefore, the first electrode 16 arranged on the light irradiation side (upper side in the drawing) has light transmission to the irradiation light. More specifically, the light transmittance of the first electrode 16 on the light irradiation side is preferably at least 10% or more, more preferably 30% or more of the irradiation amount of the irradiation light. Alternatively, the first electrode 16 has an opening portion capable of transmitting light. That is, the shape of the first electrode 16 is not limited to the thin film shape, but may be a grid shape, a particle shape, or a wire shape. The aperture ratio is at least 10% or more, more preferably 30% or more.

In the above, the photovoltaic layer 15 having a laminated structure of three photovoltaic layers (first photovoltaic layer 12, second photovoltaic layer 13, and third photovoltaic layer 14) is provided. Although explained as an example, it is not limited to this. The photovoltaic layer 15 may be composed of a laminated structure of two or four or more photovoltaic layers. Alternatively, one photovoltaic layer may be used instead of the laminated structure of the photovoltaic layers. Further, although the solar cell using the pin-junction semiconductor has been described above, the solar cell using the pn junction type semiconductor may be used. Further, the example in which the semiconductor layer is composed of Si and Ge is shown, but the present invention is not limited to this, and the semiconductor layer may be composed of compound semiconductor systems such as GaAs, GaInP, AlGaInP, CdTe, and CuInGaSe. Furthermore, various forms such as single crystal, polycrystalline, and amorphous can be applied. Further, the first electrode 16 and the second electrode 11 may be provided on the entire surface of the photovoltaic layer 15 or may be partially provided.

The first catalyst 17 is formed on the upper surface of the first electrode 16. The first catalyst 17 is provided to enhance the chemical reactivity (oxidation reactivity) near the surface of the first electrode 16. When an aqueous solution, that is, a solution containing H ₂ O is used as the electrolytic solution 23, the first electrode 16 oxidizes H ₂ O to generate O ₂ and H ⁺ . Therefore, the first catalyst 17 is comprised of a material that reduces the activation energy for the oxidation of H 2 _O. In other words, it is composed of a material that reduces the overvoltage in oxidizing H ₂ O to produce O ₂ and H ⁺ . Examples of such materials include manganese oxide (Mn-O), iridium oxide (Ir-O), nickel oxide (Ni-O), cobalt oxide (Co-O), iron oxide (Fe-O), and tin oxide (Sn). -O), indium oxide (In-O), or binary metal oxide such as ruthenium oxide (Ru-O), Ni-Co-O, Ni-Fe-O, La-Co-O, Ni-La A ternary metal oxide such as −O, Sr—Fe—O, a quaternary metal oxide such as Pb-Ru-Ir—O, La—Sr-Co—O, or a Ru complex or Fe complex. Examples include metal complexes. Further, the shape of the first catalyst 17 is not limited to the thin film shape, but may be a lattice shape, a particle shape, or a wire shape. Further, the catalytic performance may be provided on the metal portion in the structure in which the metal and the transparent conductive oxide are laminated on the first electrode 16, or the metal portion in the structure in which the metal and the other conductive material are composited. Further, the electrode metal itself may have catalytic performance. Thereby, the structure can be simplified.

The second catalyst 18 is formed on the lower surface of the second electrode 11. The second catalyst 18 is provided to enhance the chemical reactivity (reduction reactivity) in the vicinity of the back surface of the second electrode 11. When a solution containing CO ₂ is used as the electrolytic solution 23, CO ₂ is reduced to produce carbon compounds (for example, CO, HCOOH, CH ₄ , CH ₃ OH, C ₂ H ₅ OH, C ₂ H ₄ ) and the like. To do. Therefore, the second catalyst 18 is composed of a material that reduces the activation energy for reducing CO ₂ . In other words, it is composed of a material that reduces the overvoltage when reducing CO ₂ to produce a carbon compound. Such materials include metals such as Au, Ag, Cu, Pt, C, Ni, Zn, C, graphene, CNT (carbon nanotube), fullerenes, Ketjen black, or Pd, or at least one of them. Examples thereof include alloys and metal complexes such as Ru complex and Re complex. Further, when an aqueous solution containing no CO ₂ is used as the electrolytic solution 23, that is, H ₂ O containing no CO ₂ is used, H ₂ O is reduced to generate H ₂ . Therefore, the second catalyst 18 constructed of a material that reduces the activation energy for the reduction of H 2 _O. In other words, it is composed of a material that reduces the overvoltage when reducing H ₂ O to produce H ₂ . Examples of such a material include metals such as Ni, Fe, Pt, Ti, Au, Ag, Zn, Pd, Ga, Mn, Cd, C, and graphene, or alloys containing at least one of them. Further, the shape of the second catalyst 18 is not limited to the thin film shape, but may be a lattice shape, a particle shape, or a wire shape.

The laminated structure of the photovoltaic layer 15 may be reversed to reverse the overvoltage lowering action of the first electrode 16 and the second electrode 11 by the first catalyst 17 and the second catalyst 18.

The external power supply 32 is electrically connected between the first electrode 16 and the second electrode 11 via the first switching element 31. In other words, the first switching element 31 is formed between the external power supply 32 and the first electrode 16 or the second electrode 11. Then, by turning on the first switching element 31, the first electrode 16 and the second electrode 11 are electrically connected via the external power supply 32. On the other hand, by turning off the first switching element 31, the first electrode 16 and the second electrode 11 are electrically cut off via the external power supply 32. Further, the first electrode 16 is connected to the anode side of the external power supply 32, and the second electrode 11 is connected to the cathode side. Although the details will be described later, when there is surplus power, the external power supply 32 supplies power to the first electrode 16 and the second electrode 11.

The power demand unit 34 is electrically connected between the first electrode 16 and the second electrode 11 via the second switching element 33. Further, the power demand unit 34 is connected in parallel with the external power supply 32. In other words, the second switching element 33 is formed between the power demand unit 34 and the first electrode 16 or the second electrode 11. Then, by turning on the second switching element 33, the first electrode 16 and the second electrode 11 are electrically connected via the power demand unit 34. On the other hand, by turning off the first switching element 31, the first electrode 16 and the second electrode 11 are electrically cut off via the power demand unit 34. Although the details will be described later, power is supplied from the photovoltaic layer 15 to the power demand unit 34 when there is no surplus power. The electric power demand unit 34 is, for example, a storage battery for storing electric power or an area for consuming electric power.

The switching element control unit 41 controls on / off of the first switching element 31 and the second switching element 33 according to conditions such as the presence / absence of surplus power exceeding the demand of the power demand unit 34 and the presence / absence of solar energy. ..

More specifically, the switching element control unit 41 turns off the first switching element 31 and the second switching element 33 when there is surplus power and there is solar energy. As a result, the first electrode 16 and the second electrode 11 are electrically connected only via the photovoltaic layer 15. As a result, electrolysis is performed in the first electrode 16 and the second electrode 11 by the electromotive force of the photovoltaic layer 15, and chemical energy is generated. That is, the chemical reaction apparatus functions as an artificial photosynthesis system.

On the other hand, the switching element control unit 41 turns off the second switching element 33 and turns on the first switching element 31 when there is surplus power and there is no solar energy. As a result, the first electrode 16 and the second electrode 11 are electrically connected via the external power supply 32. As a result, electrolysis is performed in the first electrode 16 and the second electrode 11 by the electromotive force of the external power source 32 to generate chemical energy. That is, the chemical reactor functions as an electrolytic system.

Further, the switching element control unit 41 turns off the first switching element 31 and turns on the second switching element 32 when there is no surplus power. As a result, the photovoltaic layer 15 and the power demand unit 34 are electrically connected. As a result, electric power is supplied to the electric power demand unit 34 by the electromotive force generated by the photovoltaic layer 15. That is, the chemical reaction device functions as a solar cell.

1-2. Operation of the first embodiment FIG. 2 is a diagram showing the operation of the artificial photosynthesis system of the chemical reaction apparatus according to the first embodiment. Artificial photosynthesis systems are mainly used when there is surplus power and when there is solar energy.

As shown in FIG. 2, when used as an artificial photosynthesis system, the switching element control unit 41 turns off the first switching element 31 and the second switching element 33. As a result, the first electrode 16 and the second electrode 11 are electrically cut off via the external power supply 32. Further, the first electrode 16 and the second electrode 11 are electrically cut off via the power demand unit 34.

Further, the electrolytic solution control unit 61 controls the amount of the electrolytic solution 23 in the electrolytic cell 21 so that the first electrode 16 and the second electrode 11 are immersed in the electrolytic solution 23. As a result, the electrolytic cell 23 is injected into the electrolytic cell 21 via the pipe 22, and the electrolytic cell 21 is filled with the electrolytic cell 23. The inside of the electrolytic cell 21 does not have to be filled with the electrolytic solution 23, and at least a part of the first electrode 16 and the second electrode 11 may be immersed in the electrolytic solution 23.

When light is irradiated from above in this state, the irradiated light passes through the first electrode 16 and reaches the photovoltaic layer 15. When the photovoltaic layer 15 absorbs light, it generates electrons and holes paired with them, and separates them. That is, in each photovoltaic layer (first photovoltaic layer 12, second photovoltaic layer 13, and third photovoltaic layer 14), electrons are placed on the n-type semiconductor layer side (second electrode 11 side). Moves, and holes generated as a pair of electrons move to the p-type semiconductor layer side (first electrode 16 side), and charge separation occurs. As a result, an electromotive force is generated in the photovoltaic layer 15.

The electrons generated in the photovoltaic layer 15 and transferred to the second electrode 11 which is the electrode on the cathode side are used for the reduction reaction in the vicinity of the back surface of the second electrode 11 (near the second catalyst 18). On the other hand, the holes generated in the photovoltaic layer 15 and moved to the first electrode 16 which is the electrode on the anode side are used for the oxidation reaction near the surface of the first electrode 16 (near the first catalyst 17). .. More specifically, the reaction of Eq. (1) occurs near the front surface of the first electrode 16 in contact with the electrolytic solution 23, and the reaction of Eq. (2) occurs near the back surface of the second electrode 11.

^{_{2H 2 O → 4H + + O}} 2 + 4e - ··· (1)
^{_{2CO 2 + 4H + + 4e -}} → 2CO + 2H 2 O ··· (2)
As shown in the equation (1), H ₂ O is oxidized (loses electrons) near the surface of the first electrode 16 to generate oxygen (O ₂ ) and hydrogen ions (H ⁺ ). Then, the H ⁺ generated on the first electrode 16 side moves to the second electrode 11 side.

As shown in the equation (2), near the back surface of the second electrode 11, CO ₂ reacts with the transferred H ⁺ to generate carbon monoxide (CO) and H ₂ O. That is, CO ₂ is reduced (obtaining electrons).

At this time, the photovoltaic layer 15 needs to have an open circuit voltage equal to or larger than the potential difference between the standard redox potential of the oxidation reaction generated at the first electrode 16 and the standard redox potential of the reduction reaction generated at the second electrode 11. For example, the standard redox potential of the oxidation reaction in the formula (1) is 1.23 [V], and the standard redox potential of the reduction reaction in the formula (2) is −0.1 [V]. Therefore, the open circuit voltage of the photovoltaic layer 15 needs to be 1.33 [V] or more. More preferably, the open circuit voltage needs to be equal to or larger than the potential difference including the overvoltage. More specifically, for example, when the overvoltages of the oxidation reaction in the equation (1) and the reduction reaction in the equation (2) are 0.2 [V], the open circuit voltage is 1.73 [V] or more. desirable.

It should be noted that not only the reduction reaction from CO ₂ to CO shown in the formula (2) but also the reduction reaction from CO ₂ to HCOOH, CH ₄ , C ₂ H ₄ , CH ₃ OH, C ₂ H ₅ OH and the like occur. It is possible. It is also possible to cause a reduction reaction of H ₂ O used in the second solution 82, and it is also possible to generate H ₂ . Moreover, the reducing substance of CO ₂ produced can be changed by changing the amount of water (H ₂ O) in the solution. For example, the production ratio of HCOOH, CH ₄ , CH ₃ OH, C ₂ H ₅ OH, H ₂ or the like can be changed.

As described above, in the artificial photosynthesis system, solar energy generates an electromotive force in the photovoltaic layer 15, and this electromotive force causes a redox reaction (electrolytic reaction) to generate chemical energy. That is, solar energy can be converted into chemical energy.

FIG. 3 is a diagram showing the operation of the electrolytic system of the chemical reaction apparatus according to the first embodiment. Electrolytic systems are mainly used when there is surplus power and there is no solar energy. For example, an electrolytic system can be used at night.

As shown in FIG. 3, when used as an electrolytic system, the switching element control unit 41 turns on the first switching element 31. As a result, the first electrode 16 and the second electrode 11 are electrically connected via the external power supply 32. On the other hand, the switching element control unit 41 turns off the second switching element 33. As a result, the first electrode 16 and the second electrode 11 are electrically cut off via the power demand unit 34.

Further, the electrolytic solution control unit 61 controls the amount of the electrolytic solution 23 in the electrolytic cell 21 so that the first electrode 16 and the second electrode 11 are immersed in the electrolytic solution 23. As a result, the electrolytic cell 23 is injected into the electrolytic cell 21 via the pipe 22, and the electrolytic cell 21 is filled with the electrolytic cell 23. The inside of the electrolytic cell 21 does not have to be filled with the electrolytic solution 23, and at least a part of the first electrode 16 and the second electrode 11 may be immersed in the electrolytic solution 23.

When an electromotive force is generated in the external power supply 32 in this state, holes move to the first electrode 16 side connected to the anode side of the external power supply 32. On the other hand, electrons move to the second electrode 11 side connected to the cathode side of the external electrode 32. The electrons transferred to the second electrode 11 which is the electrode on the cathode side are used for the reduction reaction in the vicinity of the back surface of the second electrode 11. On the other hand, the holes generated in the photovoltaic layer 15 and moved to the first electrode 16 which is the electrode on the anode side are used for the oxidation reaction near the surface of the first electrode 16. More specifically, the reaction of Eq. (1) occurs near the front surface of the first electrode 16 in contact with the electrolytic solution 23, and the reaction of Eq. (2) occurs near the back surface of the second electrode 11.

As shown in the equation (1), H ₂ O is oxidized (lost electrons) near the surface of the first electrode 16 to generate O ₂ and hydrogen ions (H ⁺ ). Then, the H ⁺ generated on the first electrode 16 side moves to the second electrode 11 side.

As shown in the equation (2), CO ₂ reacts with the moved H ⁺ in the vicinity of the back surface of the second electrode 11, and CO and H ₂ O are generated. That is, CO ₂ is reduced (obtaining electrons).

At this time, the photovoltaic layer 15 needs to have an open circuit voltage equal to or larger than the potential difference between the standard redox potential of the oxidation reaction generated at the first electrode 16 and the standard redox potential of the reduction reaction generated at the second electrode 11. For example, the standard redox potential of the oxidation reaction in the formula (1) is 1.23 [V], and the standard redox potential of the reduction reaction in the formula (2) is −0.1 [V]. Therefore, the open circuit voltage of the photovoltaic layer 15 needs to be 1.33 [V] or more. More preferably, the open circuit voltage needs to be equal to or larger than the potential difference including the overvoltage. More specifically, for example, when the overvoltages of the oxidation reaction in the equation (1) and the reduction reaction in the equation (2) are 0.2 [V], the open circuit voltage is 1.73 [V] or more. desirable.

It should be noted that not only the reduction reaction from CO ₂ to CO shown in the formula (2) but also the reduction reaction from CO ₂ to HCOOH, CH ₄ , C ₂ H ₄ , CH ₃ OH, C ₂ H ₅ OH and the like occur. It is possible. In addition, it is possible to cause a reduction reaction of H ₂ O used in the electrolytic solution 23, and it is also possible to generate H ₂ . Moreover, the reducing substance of CO ₂ produced can be changed by changing the amount of water (H ₂ O) in the solution. For example, the production ratio of HCOOH, CH ₄ , CH ₃ OH, C ₂ H ₅ OH, H ₂ or the like can be changed.

Further, due to the diode characteristics of the semiconductor layer constituting the photovoltaic layer 15, the current flowing may be small depending on the orientation of the configuration of the semiconductor layer.

As described above, in the electrolytic system, an electromotive force is generated in the external power source 32 by the electric energy of the surplus electric power, and the oxidation-reduction reaction (electrolytic reaction) is caused by this electromotive force to generate chemical energy. That is, electrical energy can be converted into chemical energy.

FIG. 4 is a diagram showing the solar cell operation of the chemical reaction apparatus according to the first embodiment. FIG. 5 is a diagram showing a modified example of the solar cell operation of the chemical reaction apparatus according to the first embodiment. Solar cells are mainly used when there is no surplus power.

As shown in FIG. 4, when used as a solar cell, the switching element control unit 41 turns off the first switching element 31. As a result, the first electrode 16 and the second electrode 11 are electrically cut off via the external power supply 32. On the other hand, the switching element control unit 41 turns on the second switching element 33. As a result, the first electrode 16 and the second electrode 11 are electrically connected via the power demand unit 34.

At this time, it is preferable that the movement of ions between the first electrode 16 and the second electrode 11 does not occur through the electrolytic solution 23. That is, it is better that no current flows through the electrolytic solution 23. This is because the photovoltaic power layer 15 discharges power to the power demand unit 34 at the same time as power generation. Therefore, the electrolytic solution control unit 61 controls the amount of the electrolytic solution 23 in the electrolytic cell 21 so that the first electrode 16 and the second electrode 11 are not immersed in the electrolytic solution 23. As a result, the electrolytic solution 23 is discharged from the electrolytic cell 21 via the pipe 22, and the electrolytic cell 21 is filled with air.

The inside of the electrolytic cell 21 does not have to be filled with air, and at least a part of the first electrode 16 and the second electrode 11 may not be immersed in the electrolytic solution 23. At this time, as shown in FIG. 5, a part of the electrolytic cell 21 may be filled with the gas (for example, O ₂ or the like) generated by the artificial photosynthesis system or the electrolysis system described above. In this case, it is not necessary to discharge the electrolytic solution 23 from the electrolytic cell 21 via the pipe 22. That is, it is not necessary to use a pump or the like provided in the pipe 22, and energy loss can be reduced. Further, in this case, it is necessary to arrange the first electrode 16 on the side opposite to gravity.

Further, the electrolytic solution 23 discharged to the electrolytic solution storage tank connected to the pipe 22 may be stored via the pipe 22. Further, the inside of the electrolytic cell 21 may be filled with a non-conductive liquid instead of air.

When light is irradiated from above in this state, the irradiated light passes through the first electrode 16 and reaches the photovoltaic layer 15. When the photovoltaic layer 15 absorbs light, it generates electrons and holes paired with them, and separates them. That is, in each photovoltaic layer (first photovoltaic layer 12, second photovoltaic layer 13, and third photovoltaic layer 14), electrons are placed on the n-type semiconductor layer side (second electrode 11 side). Moves, and holes generated as a pair of electrons move to the p-type semiconductor layer side (first electrode 16 side), and charge separation occurs. As a result, an electromotive force is generated in the photovoltaic layer 15. The electromotive force generated by the photovoltaic layer 15 can supply electric power to the electric power demand unit 34.

As described above, in the solar cell, solar energy generates an electromotive force in the photovoltaic layer 15, and this electromotive force generates electric energy. That is, solar energy can be converted into electrical energy.

FIG. 6 is a flowchart showing the operation of the chemical reaction apparatus according to the first embodiment.

As shown in FIG. 6, first, in step S1, the chemical reaction apparatus confirms whether or not there is surplus power exceeding the demand of the power demand unit 34.

If there is no surplus power in step S1, the chemical reactor functions as a solar cell in step S2. More specifically, when there is no surplus power, the switching element control unit 41 turns off the first switching element 31 and turns on the second switching element 32. As a result, the photovoltaic layer 15 and the power demand unit 34 are electrically connected, and power is supplied to the power demand unit 34 by the electromotive force generated by the photovoltaic layer 15.

If there is surplus power in step S1, the chemical reactor checks in step S3 whether or not there is solar energy.

In the absence of solar energy in step S3, the chemical reactor functions as an electrolytic system in step S4. More specifically, when there is no solar energy, the switching element control unit 41 turns off the second switching element 33 and turns on the first switching element 31. As a result, the first electrode 16 and the second electrode 11 are electrically connected via the external power source 32, and electrolysis is performed in the first electrode 16 and the second electrode 11 by the electromotive force of the external power source 32 to carry out chemical energy. Is generated.

When there is solar energy in step S3, the chemical reactor functions as an artificial photosynthesis system in step S5. More specifically, when there is solar energy, the switching element control unit 41 turns off the first switching element 31 and the second switching element 33. As a result, the first electrode 16 and the second electrode 11 are electrically connected only via the photoelectromotive force layer 15, and the electromotive force generated by the photoelectromotive force layer 15 causes electrolysis in the first electrode 16 and the second electrode 11. It is done and chemical energy is generated.

As described above, the chemical reaction apparatus appropriately operates as an artificial photosynthesis system, a solar cell, and an electrolysis system according to various conditions.

1-3. Effect of 1st Embodiment According to the 1st embodiment, the chemical reaction apparatus accommodates a laminate 10 including a first electrode 16, a photovoltaic layer 15, and a second electrode 11, and a laminate 10. The electrolytic cell 21 is composed of an external power supply 32 and a power demand unit 34 that can be electrically connected or cut off from the laminated body 10. That is, the connection between the laminate 10 and the external power supply 32 and the connection between the laminate 10 and the power demand unit 34 can be switched. It is also possible that the laminate 10 is not electrically connected (cut off) to either the external power supply 32 or the power demand unit 34.

As a result, the chemical reaction apparatus can function as an electrolytic system by electrically connecting the laminate 10 and the external power supply 32. Further, by electrically connecting the laminated body 10 and the electric power demand unit 34, the chemical reaction device can function as a solar cell. Further, by electrically shutting off the laminated body 10, the external power source 32, and the power demand unit 34, the chemical reaction apparatus can function as an artificial photosynthesis system. These connections are determined by the presence or absence of surplus power and the presence or absence of solar energy.

That is, according to the first embodiment, the artificial photosynthesis system, the solar cell, or the electrolytic system is appropriately used so that the energy conversion efficiency becomes high according to various conditions such as the presence / absence of surplus power and the presence / absence of solar energy. An integrated chemical reactor that works can be provided.

1-4. Modification Example of the First Embodiment FIG. 7 is a schematic configuration diagram showing a configuration of a first modification of the chemical reaction apparatus according to the first embodiment.

As shown in FIG. 7, in the first modification of the chemical reaction apparatus according to the first embodiment, the second electrode 11 physically divides the electrolytic cell 21 into the first electrolytic cell 25 and the second electrolytic cell 26. To separate.

The first electrolytic cell 25 accommodates the first electrolytic solution 23a so as to immerse the surface (first catalyst 17) of the first electrode 16. The first electrolyte solution 23a is a solution containing, for example, _{H 2} O. Such solutions include but are intended to include any electrolyte, it is desirable is to promote the oxidation reaction of H 2 _O. The upper surface of the first electrolytic cell 25 is provided with a window portion made of, for example, glass or acrylic, which has high light transmittance. The irradiation light is emitted from above the first electrolytic cell 25.

Further, a pipe 22a is connected to the first electrolytic cell 25. The pipe 22a injects the first electrolytic cell 23a into the first electrolytic cell 25, or discharges the first electrolytic cell 23a from the first electrolytic cell 25.

The second electrolytic cell 26 accommodates the second electrolytic solution 23b so as to immerse the back surface (second catalyst 18) of the second electrode 11. The second electrolytic solution 23b is, for example, a solution containing CO ₂ . It is desirable that the second electrolytic solution 23b has a high absorption rate of CO ₂ , and examples of the solution containing H ₂ O include aqueous solutions of NaHCO ₃ and KHCO ₃ . Further, the first electrolytic solution 23a and the second electrolytic solution 23b may be the same solution, but since it is preferable that the second electrolytic solution 23b has a high CO ₂ absorption amount, the first electrolytic solution 23a and the second electrolytic solution 23b May use another solution. The second electrolyte solution 23b reduces the reduction potential of the CO _2, high ion conductivity, it is desirable to have CO ₂ absorbent that absorbs CO _2. Such electrolytic solution, and a cation such as an imidazolium ion or a pyridinium ion, consists salts with BF ^4-or PF ^6- such anions, ionic liquids or aqueous solutions thereof in a liquid state in a wide temperature range Can be mentioned. Alternatively, examples of the electrolytic solution include an amine solution such as ethanolamine, imidazole, or pyridine, or an aqueous solution thereof. The amine may be a primary amine, a secondary amine, or a tertiary amine. Examples of the primary amine include methylamine, ethylamine, propylamine, butylamine, pentylamine, hexylamine and the like. The hydrocarbon of amine may be substituted with alcohol, halogen or the like. Examples of those in which the hydrocarbon of the amine is substituted include methanolamine, ethanolamine, chloromethylamine and the like. Further, an unsaturated bond may be present. The same applies to these hydrocarbons as secondary amines and tertiary amines. Examples of the secondary amine include dimethylamine, diethylamine, dipropylamine, dibutylamine, dipentylamine, dihexylamine, dimethanolamine, diethanolamine, dipropanolamine and the like. The substituted hydrocarbons may be different. This also applies to tertiary amines. For example, examples of different hydrocarbons include methyl ethylamine, methyl propylamine, and the like. Tertiary amines include trimethylamine, triethylamine, tripropylamine, tributylamine, trihexylamine, trimethanolamine, triethanolamine, tripropanolamine, tributanolamine, tripropanolamine, triexanolamine, methyldiethylamine, or Examples thereof include methyldipropylamine. The cations of the ionic liquid include 1-ethyl-3-methylimidazolium ion, 1-methyl-3-propylimidazolium ion, 1-butyl-3-methylimidazolium ion, and 1-methyl-3-pentylimidazolium ion. , Or 1-hexyl-3-methylimidazolium ion and the like. Further, the 2-position of the imidazolium ion may be substituted. Examples of the imidazolium ion substituted at the 2-position include 1-ethyl-2,3-dimethylimidazolium ion, 1,2-dimethyl-3-propylimidazolium ion, and 1-butyl 2,3-dimethyl. Examples thereof include imidazolium ion, 1,2-dimethyl-3-pentylimidazolium ion, 1-hexyl-2,3-dimethylimidazolium ion and the like. Examples of the pyridinium ion include methylpyridinium, ethylpyridinium, propylpyridinium, butylpyridinium, pentylpyridinium, hexylpyridinium and the like. Both the imidazolium ion and the pyridinium ion may be substituted with an alkyl group or may have an unsaturated bond. Examples of the anion, fluoride ion, chloride ion, bromide ion, iodide ^{_{ion, BF 4-, PF 6-, CF}} 3 COO -, CF 3 SO 3-, NO 3-, SCN -, (CF 3 SO 2 ) ₃ C ⁻ , bis (trifluoromethoxysulfonyl) imide, bis (trifluoromethoxysulfonyl) imide, bis (perfluoroethylsulfonyl) imide and the like can be mentioned. Further, zwitterion may be obtained by connecting a cation and an anion of an ionic liquid with a hydrocarbon.

Further, a pipe 22b is connected to the second electrolytic cell 26. The pipe 22b injects the second electrolytic cell 23b into the second electrolytic cell 26, or discharges the second electrolytic cell 23b from the second electrolytic cell 26.

The electrolytic cell control unit 61 controls the first electrolytic cell 23a in the first electrolytic cell 25 and the second electrolytic cell 23b in the second electrolytic cell 26. More specifically, the electrolytic cell control unit 61 measures the amounts of the first electrolytic cell 23a in the first electrolytic cell 25 and the second electrolytic cell 23b in the second electrolytic cell 26, and the first electrolysis by the pipe 22a. The injection and discharge of the second electrolytic solution 23b by the liquid 23a and the pipe 22b are controlled. As a result, the electrolytic cell control unit 61 fills the inside of the first electrolytic cell 25 with the first electrolytic cell 23a so that a sufficient electrolytic reaction occurs when used as an artificial photosynthesis system and an electrolytic system, and the second electrolytic cell 26 The inside is filled with the second electrolytic solution 23b. Further, when the electrolytic solution control unit 61 is used as a solar cell, the first electrolytic cell 23a or the first electrolytic cell 23a or the first electrolytic cell is prevented from flowing into the first electrolytic cell 23a or the second electrolytic cell 23b. 2 The second electrolytic cell 23b is discharged from the electrolytic cell 26, and the inside of the first electrolytic cell 25 or the second electrolytic cell 26 is filled with air.

The second electrode 11 physically separates the electrolytic cell 21 into the first electrolytic cell 25 and the second electrolytic cell 26. The back surface of the second electrode 11 is arranged on the side of the second electrolytic cell 26 and is housed in the second electrolytic cell 26. At this time, the surface of the second electrode 11 is arranged on the side of the first electrolytic cell 25, but the second electrode 11 and the first electrolytic solution 22a are formed by forming an insulating layer (not shown) on the surface of the second electrode 11. Can be electrically insulated to suppress these reactions. Further, the reaction may be suppressed by replacing the first electrolytic solution 22a with a non-conductive liquid or gas.

Further, the second electrode 11 has an ion transfer path in the exposed portion thereof. The ion transfer path is, for example, a plurality of pores penetrating from the front surface to the back surface thereof. The pores selectively allow only ions (for example, H ions (H ⁺ )) generated by the oxidation reaction of the first electrode 16 in the first electrolytic cell 25 to pass through the second electrolytic cell 26. Ions that have passed through the pores, is converted by the reduction reaction at the second electrode 11 of the second electrolytic cell 26 to the O _2, H 2 or an organic _compound, and the like.

Further, the pores may have a size that allows ions to pass through. For example, the lower limit of the diameter of the pores (diameter equivalent to a circle) is preferably 0.3 nm or more. Further, the area ratio S1 / S2 of the total area S1 of the plurality of pores and the area S2 of the ion permeable member 21a is 0.9 or less, preferably 0.6 or less so as not to impair the mechanical strength. Further, the shape of the pores is not limited to a circular shape, and may be an elliptical shape, a triangular shape, or a square shape. The arrangement of the pores is not limited to a square lattice, and may be a triangular lattice or random. Further, the pores may be filled with the ion exchange membrane 19. Examples of the ion exchange membrane include a cation exchange membrane such as Nafion or Flemion, and an anion exchange membrane such as Neosepta or Selemion. Further, the pores may be filled with a glass filter or agar.

The second electrode 11 may have a plurality of slits that penetrate from the front surface to the back surface and are filled with the ion exchange membrane 19 instead of the pores. The slit selectively allows only ions (for example, H ions (H ⁺ )) generated by the oxidation reaction of the first electrode 16 in the first electrolytic cell 25 to pass through the second electrolytic cell 26.

Further, the movement of ions may be promoted by providing a pump in the ion movement path.

Further, by providing a valve in the ion transfer flow path, the electrolytic cell is filled in each electrolytic cell (first electrolytic cell 25 and second electrolytic cell 26) and is not filled with the electrolytic cell (filled with air). ) State and can be configured.

In the first modification, by separating the electrolytic cell 21 into the first electrolytic cell 25 and the second electrolytic cell 26, different electrolytic cells (first electrolytic cell 23a and second electrolytic cell) that easily react in each electrolytic cell are easily reacted. 23b) can be filled. Further, by separating the electrolytic cell 21 into the first electrolytic cell 25 and the second electrolytic cell 26, an oxidation reaction is carried out on the first electrolytic cell 25 side and a reduction reaction is carried out on the second electrolytic cell 26 side. As a result, the product of the oxidation reaction (for example, O ₂ ) can be recovered in the first electrolytic cell 25, and the product of the reduction reaction (for example, CO) can be recovered in the second electrolytic cell 26. That is, the product produced by the oxidation reaction and the product produced by the reduction reaction can be separated and recovered.

Further, different reactions can be caused by changing the electrolytic solutions in the first electrolytic cell 25 and the second electrolytic cell 26 depending on whether the system is used as an electrolytic system or an artificial photosynthesis system. As a result, an optimum reaction can be caused for a reaction current density that differs depending on the light intensity, the amount of surplus power, and the like.

FIG. 8 is a schematic configuration diagram showing a configuration of a second modification of the chemical reaction apparatus according to the first embodiment.

As shown in FIG. 8, in the second modification of the chemical reaction apparatus according to the first embodiment, the sensor units 42 and 43 are electrically connected between the first electrode 16 and the second electrode 11. To.

The sensor unit 42 is electrically connected between the first electrode 16 and the second electrode 11 via a switching element 31 and an external power supply 32. In other words, the first switching element 31 is formed between the sensor unit 42 and the first electrode 16 or the second electrode 11. Then, by turning on the first switching element 31, the first electrode 16 and the second electrode 11 are electrically connected via the external power supply 32 and the sensor unit 42. On the other hand, by turning off the first switching element 31, the first electrode 16 and the second electrode 11 are electrically cut off via the external power supply 32 and the sensor unit 42. That is, the sensor unit 42 functions when the chemical reaction apparatus is mainly used as an electrolytic system.

The sensor unit 43 is electrically connected between the first electrode 16 and the second electrode 11 via a third switching element 35. In other words, the third switching element 35 is formed between the sensor unit 43 and the first electrode 16 or the second electrode 11. Then, by turning on the third switching element 35, the first electrode 16 and the second electrode 11 are electrically connected via the sensor unit 43. On the other hand, by turning off the third switching element 35, the first electrode 16 and the second electrode 11 are electrically cut off via the sensor unit 43. That is, the sensor unit 43 functions when the chemical reaction apparatus is mainly used as an artificial photosynthesis system.

For example, in the case of an electrolytic system, the sensor unit 42 uses the electromotive force of the external power source 32 to capture an electric signal obtained by the reaction of the electrolytic solution 23 with the first electrode 16 and the second electrode 11. As a result, in the case of the electrolytic system, the sensor unit 42 has the pH of the electrolytic solution 23, the concentration of the electrolytic solution 23, the composition of the electrolytic solution 23, the pressure in the electrolytic cell 21, the temperature in the electrolytic cell 21, and the light intensity. Etc. are measured.

The sensor unit 43 utilizes the electromotive force of the photovoltaic layer 15 in the case of an artificial photosynthesis system, for example, and captures an electric signal obtained by the reaction of the electrolytic solution 23 with the first electrode 16 and the second electrode 11. As a result, in the case of the artificial photosynthesis system, the sensor unit 43 determines the pH of the electrolytic cell 23, the concentration of the electrolytic cell 23, the composition of the electrolytic cell 23, the pressure in the electrolytic cell 21, the temperature in the electrolytic cell 21, and the light. Measure strength, etc. Since the sensor unit 43 utilizes the electromotive force of the photovoltaic layer 15, it can operate without a power source.

When used as an artificial photosynthesis system, it is conceivable that the sensor 43 does not function due to the electromotive force of the photovoltaic layer 15 due to its weak light intensity. In this case, the sensor unit 42 may be temporarily operated by the external power supply 32 to measure various requirements. On the other hand, the same applies when used as an electrolytic system. That is, when used as an electrolytic system, the sensor unit 43 may temporarily function by the electromotive force of the photovoltaic layer 15 to measure various requirements.

In particular, the sensor units 42 and 43 are suitable for those that generate light by a reaction, those that generate a reaction by light, and those that change the reaction by light. The light is not limited to visible light, but may be electromagnetic waves or radiation acting on the photovoltaic layer 15. By capturing the electric signal, the sensor units 42 and 43 change the absorption of light due to the reaction or the state (pH, concentration, and composition) of the electrolytic solution 23 and the progress of the reaction according to the light and radiation generated by the reaction. It is also possible to detect the condition.

In the second modification, the pH of the electrolytic cell 23, the concentration of the electrolytic cell 23, the composition of the electrolytic cell 23, the pressure in the electrolytic cell 21, the temperature in the electrolytic cell 21, and the light intensity are determined by the sensor units 42 and 43. Etc. are measured. Thereby, the conditions of the electrolytic solution 23 and the electrolytic cell 21 for promoting the electrolytic reaction can be appropriately adjusted.

The following configuration may be applied as another modification.

Light energy may be stored as a reducer of a substance by the electromotive force generated by the photovoltaic layer 15 in the artificial photosynthesis system. In other words, a substance may be reduced by light energy, and the reduced substance may be stored as reducing energy. Here, the reducing body means a substance having a reducing power. In other words, a reducing substance is one that oxidizes itself to lose an electron and gives the electron to another substance to reduce the other substance. Examples of converting light energy into reduction energy include conversion of iron trivalent ions (Fe ³⁺ ) to divalent ions (Fe ²⁺ ) by light energy, and conversion of iodine monovalent ions (I ⁻ ) by light energy to 3 Conversion to valent ions (I ^3- ) and the like can be mentioned. Moreover, H ⁺ may be stored as a reducing body.

As described above, the reduced product obtained in the artificial photosynthesis system may be further reduced by the electromotive force generated by the external power source 32 in the electrolytic system. As a result, it can be converted into a reduced product having a higher energy density.

Further, electric energy may be obtained from the reducing energy by performing a reaction of oxidizing the reducing body obtained by the artificial photosynthesis system and returning it to its original state. That is, it becomes an artificial photosynthesis system having a power storage function. Further, like a normal battery, a compound such as lithium may be used as an electrolyte to provide a storage function by interacting with the electrodes.

It can also be used as a fuel cell. More specifically, light energy decomposes water to produce hydrogen and oxygen. By sharing at least one electrode with the obtained oxygen and hydrogen, water is generated by hydrogen and oxygen. As a result, electric power can be obtained. That is, the fuel cell can be integrated into the artificial photosynthesis system. The reaction efficiency can be improved by providing a flow path in the electrolytic cell 21 like a normal fuel cell. Further, the polymer electrolyte membrane used for the polymer electrolyte fuel cell may be formed between the first electrode 16 and the second electrode 11. Further, the heat associated with the power generation at this time or the heat of the electrolyte heated by sunlight may be used as the utilization medium. The heat utilization medium is not limited to the electrolyte, and may be used by providing another heat medium on the second electrode 11 or on a copper pipe (not shown) in the electrolytic solution 23.

2. 2. Second Embodiment The chemical reaction apparatus according to the second embodiment will be described below with reference to FIGS. 9 to 15.

In the chemical reaction apparatus according to the second embodiment, the electrolytic cell 21 is separated not only from the laminate 10 including the first electrode 16, the photovoltaic layer 15, and the second electrode 11, but also from the second electrode 11. Third electrodes 51 facing each other are arranged. Then, an external power source 32 is electrically connected between the second electrode 11 and the third electrode 51, and the second electrode 11, the third electrode 51, and the external power source 32 can function as an electrolytic system. The second embodiment will be described in detail below.

In the second embodiment, the same points as those in the first embodiment will be omitted as appropriate, and the differences will be mainly described.

2-1. Configuration of the Second Embodiment FIG. 9 is a schematic configuration diagram showing a configuration example of the chemical reaction apparatus according to the second embodiment. In addition, in FIG. 9, the laminated body 10, the third electrode 51, and the electrolytic cell 21 show the cross-sectional structure thereof.

As shown in FIG. 9, in the chemical reaction apparatus according to the second embodiment, the difference from the first embodiment is that not only the first electrode 16 and the second electrode 11 but also the third electrode 51 is provided. Is.

The third electrode 51 is housed in the electrolytic cell 21, and is arranged so as to be separated from the second electrode 11 on the side opposite to the light irradiation side and facing the second electrode 11. The third electrode 51 is composed of, for example, a metal plate such as Cu, Al, Ti, Ni, Fe, or Ag, or an alloy plate containing at least one of them, such as SUS. Further, the third electrode 51 may be made of a conductive resin or the like. Further, the third electrode 51 may be made of a semiconductor substrate such as Si or Ge.

Since the third electrode 51 is arranged on the side opposite to the light irradiation side, there is no particular limitation on the light transmission and the shape.

Further, a third catalyst (not shown) may be formed on the surface of the third electrode 51. The third catalyst is provided to enhance the chemical reactivity (oxidation reactivity) near the surface of the third electrode 51. When an aqueous solution, that is, a solution containing H ₂ O is used as the electrolytic solution 23, the third electrode 51 oxidizes H ₂ O to produce O ₂ and H ⁺ . Therefore, the third catalyst is composed of a material that reduces the activation energy for the oxidation of H 2 _O. In other words, it is composed of a material that reduces the overvoltage in oxidizing H ₂ O to produce O ₂ and H ⁺ . Such materials include dual metal oxides such as Mn-O, Ir-O, Ni-O, Co-O, Fe-O, Sn-O, In-O, or Ru-O, Ni-Co. Three-way metal oxides such as -O, Ni-Fe-O, La-Co-O, Ni-La-O, Sr-Fe-O, Pb-Ru-Ir-O, La-Sr-Co-O Such as quaternary metal oxides, or metal complexes such as Ru complex or Fe complex. The shape of the third catalyst is not limited to the thin film shape, but may be a lattice shape, a particle shape, or a wire shape.

The external power supply 32 is electrically connected between the second electrode 11 and the third electrode 51 via the first switching element 31. In other words, the first switching element 31 is formed between the external power supply 32 and the second electrode 11 or the third electrode 51. Then, by turning on the first switching element 31, the second electrode 11 and the third electrode 51 are electrically connected via the external power supply 32. On the other hand, by turning off the first switching element 31, the second electrode 11 and the third electrode 51 are electrically cut off via the external power supply 32. Further, the third electrode 51 is connected to the anode side of the external power supply 32, and the second electrode 11 is connected to the cathode side. Although the details will be described later, when there is surplus power, the external power supply 32 supplies power to the second electrode 11 and the third electrode 51.

The switching element control unit 41 controls on / off of the first switching element 31 and the second switching element 33 according to conditions such as the presence / absence of surplus power exceeding the demand of the power demand unit 34 and the presence / absence of solar energy. ..

More specifically, the switching element control unit 41 turns off the first switching element 31 and the second switching element 33 when there is surplus power and there is solar energy. As a result, the first electrode 16 and the second electrode 11 are electrically connected only via the photovoltaic layer 15. As a result, electrolysis is performed in the first electrode 16 and the second electrode 11 by the electromotive force of the photovoltaic layer 15, and chemical energy is generated. That is, the chemical reaction apparatus functions as an artificial photosynthesis system.

On the other hand, the switching element control unit 41 turns off the second switching element 33 and turns on the first switching element 31 when there is surplus power and there is no solar energy. As a result, the second electrode 11 and the third electrode 51 are electrically connected via the external power supply 32. As a result, electrolysis is performed at the second electrode 11 and the third electrode 51 by the electromotive force of the external power source 32 to generate chemical energy. That is, the chemical reactor functions as an electrolytic system.

Further, the switching element control unit 41 turns off the first switching element 31 and turns on the second switching element 32 when there is no surplus power. As a result, the photovoltaic layer 15 and the power demand unit 34 are electrically connected. As a result, electric power is supplied to the electric power demand unit 34 by the electromotive force generated by the photovoltaic layer 15. That is, the chemical reaction device functions as a solar cell.

2-2. Operation of the second embodiment FIG. 10 is a diagram showing the operation of the artificial photosynthesis system of the chemical reaction apparatus according to the second embodiment. Artificial photosynthesis systems are mainly used when there is surplus power and when there is solar energy.

As shown in FIG. 10, when used as an artificial photosynthesis system, the switching element control unit 41 turns off the first switching element 31 and the second switching element 33. As a result, the second electrode 11 and the third electrode 51 are electrically cut off via the external power supply 32. Further, the first electrode 16 and the second electrode 11 are electrically cut off via the power demand unit 34.

Further, the electrolytic solution control unit 61 controls the amount of the electrolytic solution 23 in the electrolytic cell 21 so that the first electrode 16 and the second electrode 11 are immersed in the electrolytic solution 23. As a result, the electrolytic cell 23 is injected into the electrolytic cell 21 via the pipe 22, and the electrolytic cell 21 is filled with the electrolytic cell 23. The inside of the electrolytic cell 21 does not have to be filled with the electrolytic solution 23, and at least a part of the first electrode 16 and the second electrode 11 may be immersed in the electrolytic solution 23.

When light is irradiated from above in this state, the same reaction as in the first embodiment occurs. That is, the reaction of the formula (1) occurs near the front surface of the first electrode 16 in contact with the electrolytic solution 23, and the reaction of the formula (2) occurs near the back surface of the second electrode 11.

As shown in the equation (1), H ₂ O is oxidized (loses electrons) near the surface of the first electrode 16 to generate O ₂ and H ⁺ . Then, the H ⁺ generated on the first electrode 16 side moves to the second electrode 11 side.

As shown in the equation (2), CO ₂ reacts with the moved H ⁺ in the vicinity of the back surface of the second electrode 11, and CO and H ₂ O are generated. That is, CO ₂ is reduced (obtaining electrons).

As described above, in the artificial photosynthesis system, an electromotive force is generated in the photovoltaic layer 15 by solar energy, and the electromotive force causes a redox reaction (electrolytic reaction) on the front surface of the first electrode 16 and the back surface of the second electrode 11. It happens and chemical energy is generated. That is, solar energy can be converted into chemical energy.

FIG. 11 is a diagram showing the operation of the electrolytic system of the chemical reaction apparatus according to the second embodiment. Electrolytic systems are mainly used when there is surplus power and there is no solar energy. For example, an electrolytic system can be used at night.

As shown in FIG. 11, when used as an electrolytic system, the switching element control unit 41 turns on the first switching element 31. As a result, the second electrode 11 and the third electrode 51 are electrically connected via the external power supply 32. On the other hand, the switching element control unit 41 turns off the second switching element 33. As a result, the first electrode 16 and the second electrode 11 are electrically cut off via the power demand unit 34.

Further, the electrolytic solution control unit 61 controls the amount of the electrolytic solution 23 in the electrolytic cell 21 so that the second electrode 11 and the third electrode 51 are immersed in the electrolytic solution 23. As a result, the electrolytic cell 23 is injected into the electrolytic cell 21 via the pipe 22, and the electrolytic cell 21 is filled with the electrolytic cell 23. The inside of the electrolytic cell 21 does not have to be filled with the electrolytic solution 23, and at least a part of the second electrode 11 and the third electrode 51 may be immersed in the electrolytic solution 23.

When an electromotive force is generated in the external power supply 32 in this state, holes move to the third electrode 51 side connected to the anode side of the external power supply 32. On the other hand, electrons move to the second electrode 11 side connected to the cathode side of the external electrode 32. The electrons transferred to the second electrode 11 which is the electrode on the cathode side are used for the reduction reaction in the vicinity of the back surface of the second electrode 11. On the other hand, the holes generated in the photovoltaic layer 15 and moved to the third electrode 51, which is the electrode on the anode side, are used for the oxidation reaction near the surface of the third electrode 51. More specifically, the reaction of Eq. (1) occurs near the front surface of the third electrode 51 in contact with the electrolytic solution 23, and the reaction of Eq. (2) occurs near the back surface of the second electrode 11.

(1) As shown in equation in the vicinity of the surface of the third electrode 51, and _{H 2} O is oxidized (loses electrons) _{O 2)} and is ^{H +} is generated. Then, the H ⁺ generated on the third electrode 51 side moves to the second electrode 11 side.

At this time, since the third electrode 51 and the second electrode 11 are formed so as to face each other, the distance between them is relatively small. Therefore, the distance that H ⁺ moves from the third electrode 51 to the second electrode 11 is small. Therefore, H ⁺ can be efficiently diffused from the third electrode 51 to the second electrode 11.

As shown in the equation (2), in the vicinity of the back surface of the second electrode 11, CO ₂ reacts with the moved H ⁺ to generate CO and H ₂ O. That is, CO ₂ is reduced (obtaining electrons).

At this time, the photovoltaic layer 15 needs to have an open circuit voltage equal to or larger than the potential difference between the standard redox potential of the oxidation reaction generated at the third electrode 51 and the standard redox potential of the reduction reaction generated at the second electrode 11. For example, the standard redox potential of the oxidation reaction in the formula (1) is 1.23 [V], and the standard redox potential of the reduction reaction in the formula (2) is −0.1 [V]. Therefore, the open circuit voltage of the photovoltaic layer 15 needs to be 1.33 [V] or more. More preferably, the open circuit voltage needs to be equal to or larger than the potential difference including the overvoltage. More specifically, for example, when the overvoltages of the oxidation reaction in the equation (1) and the reduction reaction in the equation (2) are 0.2 [V], the open circuit voltage is 1.73 [V] or more. desirable.

As described above, in the electrolytic system, an electromotive force is generated in the external power source 32 by the electric energy of the surplus electric power, and the oxidation-reduction reaction (electrolytic reaction) is caused by this electromotive force to generate chemical energy. That is, electrical energy can be converted into chemical energy.

FIG. 12 is a diagram showing the solar cell operation of the chemical reaction apparatus according to the second embodiment. FIG. 13 is a diagram showing a modified example of the solar cell operation of the chemical reaction apparatus according to the second embodiment. Solar cells are mainly used when there is no surplus power.

As shown in FIG. 12, when used as a solar cell, the switching element control unit 41 turns off the first switching element 31. As a result, the second electrode 11 and the third electrode 51 are electrically cut off via the external power supply 32. On the other hand, the switching element control unit 41 turns on the second switching element 33. As a result, the first electrode 16 and the second electrode 11 are electrically connected via the power demand unit 34.

At this time, it is preferable that the movement of ions between the first electrode 16 and the second electrode 11 does not occur through the electrolytic solution 23. That is, it is better that no current flows through the electrolytic solution 23. This is because the photovoltaic power layer 15 discharges power to the power demand unit 34 at the same time as power generation. Therefore, the electrolytic solution control unit 61 controls the amount of the electrolytic solution 23 in the electrolytic cell 21 so that the first electrode 16 and the second electrode 11 are not immersed in the electrolytic solution 23. As a result, the electrolytic solution 23 is discharged from the electrolytic cell 21 via the pipe 22, and the electrolytic cell 21 is filled with air.

The inside of the electrolytic cell 21 does not have to be filled with air, and at least a part of the first electrode 16 and the second electrode 11 may not be immersed in the electrolytic solution 23. At this time, as shown in FIG. 13, a part of the electrolytic cell 21 may be filled with the gas (for example, O ₂ or the like) generated by the artificial photosynthesis system or the electrolysis system described above. In this case, it is not necessary to discharge the electrolytic solution 23 from the electrolytic cell 21 via the pipe 22. That is, it is not necessary to use a pump or the like provided in the pipe 22, and energy loss can be reduced. Further, in this case, it is necessary to arrange the first electrode 16 on the side opposite to gravity.

When light is irradiated from above in this state, the irradiated light passes through the first electrode 16 and reaches the photovoltaic layer 15. When the photovoltaic layer 15 absorbs light, it generates electrons and holes paired with them, and separates them. That is, in each photovoltaic layer (first photovoltaic layer 12, second photovoltaic layer 13, and third photovoltaic layer 14), electrons are placed on the n-type semiconductor layer side (second electrode 11 side). Moves, and holes generated as a pair of electrons move to the p-type semiconductor layer side (first electrode 16 side), and charge separation occurs. As a result, an electromotive force is generated in the photovoltaic layer 15. The electromotive force generated by the photovoltaic layer 15 can supply electric power to the electric power demand unit 34.

As described above, in the solar cell, solar energy generates an electromotive force in the photovoltaic layer 15, and this electromotive force generates electric energy. That is, solar energy can be converted into electrical energy.

2-3. Effect of Second Embodiment According to the second embodiment, the same effect as that of the first embodiment can be obtained.

Further, according to the second embodiment, not only the laminate 10 including the first electrode 16, the photovoltaic layer 15, and the second electrode 11 but also the second electrode 11 is separated from the electrolytic cell 21. The facing third electrode 51 is accommodated. Then, by electrically connecting the external power supply 32 between the second electrode 11 and the third electrode 51, the system can function as an electrolytic system.

At this time, since the third electrode 51 and the second electrode 11 are formed so as to face each other, the distance between them is relatively small. Therefore, the distance that the H ⁺ generated by the third electrode 51 moves to the second electrode 11 is small. Therefore, H ⁺ used for the reaction of the second electrode 11 can be efficiently diffused from the third electrode 51 to the second electrode 11.

Further, the third electrode 51 is arranged on the side opposite to the light irradiation side with respect to the photovoltaic layer 15. Therefore, it is not necessary to consider the permeability as the material of the third electrode 51, and the shape thereof is not particularly limited. That is, the material and shape of the third electrode 51 can be set in consideration of only the reaction efficiency.

Further, the surface of the third electrode 51, which is different from the second catalyst 18 and the first catalyst 17, is not shown. A catalyst can be used.

The third electrode 51 is not limited to facing the second electrode 11 at a distance. The third electrode 51 may be arranged perpendicular to the second electrode 11 depending on structural problems and the like.

Further, according to the surplus power of the external power supply 32, the external power supply 32 is not only connected between the second electrode 11 and the third electrode 51, but also connected between the second electrode 11 and the first electrode 16. You may. That is, the combination of connections between the external power supply 32 and various switching elements is not limited to this example.

2-4. Modification Example of the Second Embodiment FIG. 14 is a schematic configuration diagram showing a configuration of a first modification of the chemical reaction apparatus according to the second embodiment.

As shown in FIG. 14, in the first modification of the chemical reaction apparatus according to the second embodiment, the electrolytic cell 21 is physically divided into the first electrolytic cell 25 and the second electrolytic cell 26 by the second electrode 11. Is physically separated into the second electrolytic cell 26 and the third electrolytic cell 27 by the ion exchange film 19a.

The first electrolytic cell 25 accommodates the first electrolytic solution 23a so as to immerse the surface (first catalyst 17) of the first electrode 16. The first electrolyte solution 23a is a solution containing, for example, _{H 2} O. Such solutions include but are intended to include any electrolyte, it is desirable is to promote the oxidation reaction of H 2 _O. The upper surface of the first electrolytic cell 25 is provided with a window portion made of, for example, glass or acrylic, which has high light transmittance. The irradiation light is emitted from above the first electrolytic cell 25.

Further, a pipe 22a is connected to the first electrolytic cell 25. The pipe 22a injects the first electrolytic cell 23a into the first electrolytic cell 25, or discharges the first electrolytic cell 23a from the first electrolytic cell 25.

The second electrolytic cell 26 accommodates the second electrolytic solution 23b so as to immerse the back surface (second catalyst 18) of the second electrode 11. The second electrolytic solution 23b is, for example, a solution containing CO ₂ . It is desirable that the second electrolytic solution 23b has a high absorption rate of CO ₂ , and examples of the solution containing H ₂ O include aqueous solutions of NaHCO ₃ and KHCO ₃ . Further, the first electrolytic solution 23a and the second electrolytic solution 23b may be the same solution, but since it is preferable that the second electrolytic solution 23b has a high CO ₂ absorption amount, the first electrolytic solution 23a and the second electrolytic solution 23b May use another solution. The second electrolyte solution 23b reduces the reduction potential of the CO _2, high ion conductivity, it is desirable to have CO ₂ absorbent that absorbs CO _2. Such electrolytic solution, and a cation such as an imidazolium ion or a pyridinium ion, consists salts with BF ^4-or PF ^6- such anions, ionic liquids or aqueous solutions thereof in a liquid state in a wide temperature range Can be mentioned. Alternatively, examples of the electrolytic solution include an amine solution such as ethanolamine, imidazole, or pyridine, or an aqueous solution thereof. The amine may be a primary amine, a secondary amine, or a tertiary amine. Examples of the primary amine include methylamine, ethylamine, propylamine, butylamine, pentylamine, hexylamine and the like. The hydrocarbon of amine may be substituted with alcohol, halogen or the like. Examples of those in which the hydrocarbon of the amine is substituted include methanolamine, ethanolamine, chloromethylamine and the like. Further, an unsaturated bond may be present. The same applies to these hydrocarbons as secondary amines and tertiary amines. Examples of the secondary amine include dimethylamine, diethylamine, dipropylamine, dibutylamine, dipentylamine, dihexylamine, dimethanolamine, diethanolamine, dipropanolamine and the like. The substituted hydrocarbons may be different. This also applies to tertiary amines. For example, examples of different hydrocarbons include methyl ethylamine, methyl propylamine, and the like. Tertiary amines include trimethylamine, triethylamine, tripropylamine, tributylamine, trihexylamine, trimethanolamine, triethanolamine, tripropanolamine, tributanolamine, tripropanolamine, triexanolamine, methyldiethylamine, or Examples thereof include methyldipropylamine. The cations of the ionic liquid include 1-ethyl-3-methylimidazolium ion, 1-methyl-3-propylimidazolium ion, 1-butyl-3-methylimidazolium ion, and 1-methyl-3-pentylimidazolium ion. , Or 1-hexyl-3-methylimidazolium ion and the like. Further, the 2-position of the imidazolium ion may be substituted. Examples of the imidazolium ion substituted at the 2-position include 1-ethyl-2,3-dimethylimidazolium ion, 1,2-dimethyl-3-propylimidazolium ion, and 1-butyl 2,3-dimethyl. Examples thereof include imidazolium ion, 1,2-dimethyl-3-pentylimidazolium ion, 1-hexyl-2,3-dimethylimidazolium ion and the like. Examples of the pyridinium ion include methylpyridinium, ethylpyridinium, propylpyridinium, butylpyridinium, pentylpyridinium, hexylpyridinium and the like. Both the imidazolium ion and the pyridinium ion may be substituted with an alkyl group or may have an unsaturated bond. Examples of the anion, fluoride ion, chloride ion, bromide ion, iodide ^{_{ion, BF 4-, PF 6-, CF}} 3 COO -, CF 3 SO 3-, NO 3-, SCN -, (CF 3 SO 2 ) ₃ C ⁻ , bis (trifluoromethoxysulfonyl) imide, bis (trifluoromethoxysulfonyl) imide, bis (perfluoroethylsulfonyl) imide and the like can be mentioned. Further, zwitterion may be obtained by connecting a cation and an anion of an ionic liquid with a hydrocarbon.

Further, a pipe 22b is connected to the second electrolytic cell 26. The pipe 22b injects the second electrolytic cell 23b into the second electrolytic cell 26, or discharges the second electrolytic cell 23b from the second electrolytic cell 26.

The third electrolytic cell 27 accommodates the third electrolytic solution 23c so as to immerse the third electrode 51. The third electrolyte solution 23c is the same liquid as the first electrolyte solution 23a, a solution containing for example _{H 2} O. Such solutions include but are intended to include any electrolyte, it is desirable is to promote the oxidation reaction of H 2 _O.

Further, a pipe 22c is connected to the third electrolytic cell 27. The pipe 22c injects the third electrolytic cell 23c into the third electrolytic cell 27, or discharges the third electrolytic cell 23c from the third electrolytic cell 27.

The electrolytic cell control unit 61 controls the first electrolytic cell 23a in the first electrolytic cell 25, the second electrolytic cell 23b in the second electrolytic cell 26, and the third electrolytic cell 23c in the third electrolytic cell 27. More specifically, the electrolytic solution control unit 61 includes a first electrolytic cell 23a in the first electrolytic cell 25, a second electrolytic cell 23b in the second electrolytic cell 26, and a third electrolysis in the third electrolytic cell 27. The amount of the liquid 23c is measured, and the injection and discharge of the first electrolytic solution 23a by the pipe 22a, the second electrolytic liquid 23b by the pipe 22b, and the third electrolytic liquid 23c by the pipe 22c are controlled.

As a result, when the electrolytic solution control unit 61 is used as an artificial photosynthesis system, the first electrolytic cell 25 is filled with the first electrolytic cell 23a so that a sufficient electrolytic reaction occurs, and the second electrolytic cell 26 is filled with the second electrolytic cell 26. 2 Fill with the electrolytic solution 23b. Further, when the electrolytic solution control unit 61 is used as an electrolytic system, the second electrolytic cell 26 is filled with the second electrolytic cell 23b so that a sufficient electrolytic reaction occurs, and the third electrolytic cell 27 is filled with the third electrolysis. It is filled with the liquid 23c. Further, when the electrolytic solution control unit 61 is used as a solar cell, the electrolytic cell from inside the first electrolytic cell 25 or the second electrolytic cell 26 is prevented from flowing electricity into the first electrolytic cell 23a or the second electrolytic cell 23b. The first electrolytic cell 23a or the second electrolytic cell 23b is discharged, and the inside of the first electrolytic cell 25 or the second electrolytic cell 26 is filled with air.

The second electrode 11 physically separates the electrolytic cell 21 into the first electrolytic cell 25 and the second electrolytic cell 26. The back surface of the second electrode 11 is arranged on the side of the second electrolytic cell 26 and is housed in the second electrolytic cell 26. At this time, the surface of the second electrode 11 is arranged on the side of the first electrolytic cell 25, but the second electrode 11 and the first electrolytic solution 22a are formed by forming an insulating layer (not shown) on the surface of the second electrode 11. Can be electrically insulated to suppress these reactions. Further, the reaction may be suppressed by replacing the first electrolytic solution 22a with a non-conductive liquid or gas.

Further, the second electrode 11 has an ion transfer path in the exposed portion thereof. The ion transfer path is, for example, a plurality of pores penetrating from the front surface to the back surface thereof. The pores selectively allow only ions (for example, H ions (H ⁺ )) generated by the oxidation reaction of the first electrode 16 in the first electrolytic cell 25 to pass through the second electrolytic cell 26. Ions that have passed through the pores, is converted by the reduction reaction at the second electrode 11 of the second electrolytic cell 26 to the O _2, H 2 or an organic _compound, and the like.

Further, the pores may have a size that allows ions to pass through. For example, the lower limit of the diameter of the pores (diameter equivalent to a circle) is preferably 0.3 nm or more. Further, the area ratio S1 / S2 of the total area S1 of the plurality of pores and the area S2 of the ion permeable member 21a is 0.9 or less, preferably 0.6 or less so as not to impair the mechanical strength. Further, the shape of the pores is not limited to a circular shape, and may be an elliptical shape, a triangular shape, or a square shape. The arrangement of the pores is not limited to a square lattice, and may be a triangular lattice or random. Further, the pores may be filled with the ion exchange membrane 19. Examples of the ion exchange membrane include a cation exchange membrane such as Nafion or Flemion, and an anion exchange membrane such as Neosepta or Selemion. Further, the pores may be filled with a glass filter or agar.

The second electrode 11 may have a plurality of slits that penetrate from the front surface to the back surface and are filled with the ion exchange membrane 19 instead of the pores. The slit selectively allows only ions (for example, H ions (H ⁺ )) generated by the oxidation reaction of the first electrode 16 in the first electrolytic cell 25 to pass through the second electrolytic cell 26.

Further, the movement of ions may be promoted by providing a pump in the ion movement path.

The ion exchange membrane 19a physically separates the electrolytic cell 21 into the second electrolytic cell 26 and the third electrolytic cell 27. The front surface of the ion exchange membrane 19a is arranged on the second electrolytic cell 26 side, and the back surface of the ion exchange membrane 19a is arranged on the third electrolytic cell 27 side. The ion exchange membrane 19a selectively allows only ions (for example, H ions (H ⁺ )) generated by the oxidation reaction of the third electrode 51 in the third electrolytic cell 27 to pass through the second electrolytic cell 26. Ions passed through the ion exchange membrane 19a is converted by the reduction reaction at the second electrode 11 of the second electrolytic cell 26 to the O _2, H 2 or an organic _compound, and the like. Examples of the ion exchange membrane 19a include a cation exchange membrane such as Nafion or Flemion, and an anion exchange membrane such as Neocepta or Selemion.

In the first modification, by separating the electrolytic cell 21 into the first electrolytic cell 25, the second electrolytic cell 26, and the third electrolytic cell 27, different electrolytic cells (first electrolytic cell 23a) that easily react in each electrolytic cell are generated. , The second electrolytic cell 23b, and the third electrolytic cell 23c) can be filled. Further, by separating the electrolytic cell 21 into the first electrolytic cell 25, the second electrolytic cell 26, and the third electrolytic cell 27, an oxidation reaction is carried out in the first electrolytic cell 25 and the third electrolytic cell 27, and the second electrolytic cell is carried out. The reduction reaction is carried out in the electrolytic cell 26. As a result, the product of the oxidation reaction (for example, O ₂ ) can be recovered in the first electrolytic cell 25 and the third electrolytic cell 27, and the product of the reduction reaction (for example, CO) can be recovered in the second electrolytic cell 26. .. That is, the product produced by the oxidation reaction and the product produced by the reduction reaction can be separated and recovered.

Further, the electrolytic solution may be changed depending on, for example, the reaction current density, the electrode, or the reaction. For example, the first electrolyte solution 23a and the third electrolyte solution 23c is an oxidation reaction of _{H 2} O, the third electrolyte solution 23c is the reaction by external power supply 32. Therefore, the reaction current density in the third electrolytic solution 23c can be arbitrarily changed. Therefore, it is possible to select the optimum electrolytic solution according to the reaction current density. For example, since the first electrolytic solution 23a immerses the semiconductor layer (photovoltaic power layer 15), it is preferable that the first electrolytic solution 23a does not erode the semiconductor layer. On the other hand, since the third electrolytic solution 23c is not limited, a different electrolytic solution may be used as the third electrolytic solution 23c.

FIG. 15 is a schematic configuration diagram showing a configuration of a second modification of the chemical reaction apparatus according to the second embodiment.

As shown in FIG. 15, in the second modification of the chemical reaction apparatus according to the second embodiment, the sensor unit 42 is electrically connected between the first electrode 16 and the second electrode 11, and the second electrode is second. The sensor unit 43 is electrically connected between the electrode 11 and the third electrode 51.

The sensor unit 42 is electrically connected between the second electrode 11 and the third electrode 51 via a switching element 31 and an external power supply 32. In other words, the first switching element 31 is formed between the sensor unit 42 and the second electrode 11 or the third electrode 51. Then, by turning on the first switching element 31, the second electrode 11 and the third electrode 51 are electrically connected to each other via the external power supply 32 and the sensor unit 42. On the other hand, by turning off the first switching element 31, the second electrode 11 and the third electrode 51 are electrically cut off via the external power supply 32 and the sensor unit 42. That is, the sensor unit 42 functions when the chemical reaction apparatus is mainly used as an electrolytic system.

The sensor unit 43 is electrically connected between the first electrode 16 and the second electrode 11 via a third switching element 35. In other words, the third switching element 35 is formed between the sensor unit 43 and the first electrode 16 or the second electrode 11. Then, by turning on the third switching element 35, the first electrode 16 and the second electrode 11 are electrically connected via the sensor unit 43. On the other hand, by turning off the third switching element 35, the first electrode 16 and the second electrode 11 are electrically cut off via the sensor unit 43. That is, the sensor unit 43 functions when the chemical reaction apparatus is mainly used as an artificial photosynthesis system.

For example, in the case of an electrolytic system, the sensor unit 42 uses the electromotive force of the external power supply 32 to capture an electric signal obtained by the reaction between the electrolytic solution 23 and the second electrode 11 and the third electrode 51. As a result, in the case of the electrolytic system, the sensor unit 42 has the pH of the electrolytic solution 23, the concentration of the electrolytic solution 23, the composition of the electrolytic solution 23, the pressure in the electrolytic cell 21, the temperature in the electrolytic cell 21, and the light intensity. Etc. are measured.

The sensor unit 43 utilizes the electromotive force of the photovoltaic layer 15 in the case of an artificial photosynthesis system, for example, and captures an electric signal obtained by the reaction between the electrolytic solution 23 and the first electrode 16 and the second electrode 11. As a result, in the case of the artificial photosynthesis system, the sensor unit 43 determines the pH of the electrolytic cell 23, the concentration of the electrolytic cell 23, the composition of the electrolytic cell 23, the pressure in the electrolytic cell 21, the temperature in the electrolytic cell 21, and the light. Measure strength, etc. Since the sensor unit 43 utilizes the electromotive force of the photovoltaic layer 15, it can operate without a power source.

When used as an artificial photosynthesis system, it is conceivable that the sensor 43 does not function due to the electromotive force of the photovoltaic layer 15 due to its weak light intensity. In this case, the sensor unit 42 may be temporarily operated by the external power supply 32 to measure various requirements. On the other hand, the same applies when used as an electrolytic system. That is, when used as an electrolytic system, the sensor unit 43 may temporarily function by the electromotive force of the photovoltaic layer 15 to measure various requirements.

In the second modification, the pH of the electrolytic cell 23, the concentration of the electrolytic cell 23, the composition of the electrolytic cell 23, the pressure in the electrolytic cell 21, the temperature in the electrolytic cell 21, and the light intensity are determined by the sensor units 42 and 43. Etc. are measured. Thereby, the conditions of the electrolytic solution 23 and the electrolytic cell 21 for promoting the electrolytic reaction can be appropriately adjusted.

3. 3. Third Embodiment The chemical reaction apparatus according to the third embodiment will be described below with reference to FIGS. 16 to 21.

The third embodiment is a modification of the second embodiment. In the chemical reaction apparatus according to the third embodiment, the third catalyst 52 and the third electrode 51 are formed on the back surface of the laminated body 10 (second catalyst 18) via the ion exchange membrane 19b. Then, the second electrolytic cell flow path 26a is formed inside the second electrode 11, and the third electrolytic cell flow path 27a is formed inside the third electrode 51. As a result, the reduction reaction can be carried out in the second electrolytic cell flow path 26a, and the oxidation reaction can be carried out in the third electrolytic cell flow path 27a. The third embodiment will be described in detail below.

In the third embodiment, the same points as those in the above embodiments will be omitted as appropriate, and the differences will be mainly described.

3-1. Configuration of the Third Embodiment FIG. 16 is a schematic configuration diagram showing a configuration example of a chemical reaction apparatus according to the third embodiment. In FIG. 16, the laminate 10, the third electrode 51, the third catalyst 52, the ion exchange membrane 19b, and the container 90 show their cross-sectional configurations.

As shown in FIG. 16, in the chemical reaction apparatus according to the third embodiment, the difference from the first embodiment is that the ion exchange membrane 19b is placed on the back surface of the laminate 10 (on the back surface of the second catalyst 18). , The third catalyst 52, and the third electrode 51 are formed, the second electrolytic cell flow path 26a is formed in the second electrode 11, and the third electrolytic cell flow path 27a is formed in the third electrode 51. Is.

The second electrode 11 physically separates the container 90 into the first electrolytic cell 25 and the tank 28.

The first electrolytic cell 25 is on the surface side of the second electrode 11 of the container 90, and houses the first electrolytic solution 23a so as to immerse the surface of the first electrode 16 (first catalyst 17). The first electrolyte solution 23a is a solution containing, for example, _{H 2} O. Such solutions include but are intended to include any electrolyte, it is desirable is to promote the oxidation reaction of H 2 _O. The upper surface of the first electrolytic cell 25 is provided with a window portion made of, for example, glass or acrylic, which has high light transmittance. The irradiation light is emitted from above the first electrolytic cell 25.

Further, a pipe 22a is connected to the first electrolytic cell 25. The pipe 22a injects the first electrolytic cell 23a into the first electrolytic cell 25, or discharges the first electrolytic cell 23a from the first electrolytic cell 25.

The tank 28 is on the back surface side of the second electrode 11, and houses the second catalyst 18, the ion exchange membrane 19b, the third catalyst 52, and the third electrode 51. The tank 28 does not contain the electrolytic solution inside, and is filled with, for example, air.

The second electrode 11 physically separates the container 90 into the first electrolytic cell 25 and the tank 28. The back surface of the second electrode 11 is arranged on the tank 28 side and is housed in the tank 28. At this time, the surface of the second electrode 11 is arranged on the side of the first electrolytic cell 25, but the second electrode 11 and the first electrolytic solution 22a are formed by forming an insulating layer (not shown) on the surface of the second electrode 11. Can be electrically insulated to suppress these reactions.

Further, the second electrode 11 has an ion transfer path in the exposed portion thereof. The ion transfer path is, for example, a plurality of pores penetrating from the front surface to the back surface thereof. The pores selectively allow only ions (for example, H ⁺ ) generated by the oxidation reaction of the first electrode 16 in the first electrolytic cell 25 to pass through the second electrolytic cell flow path 26a. Ions that have passed through the pores, is converted by the reduction reaction at the second electrode 11 of the second electrolytic bath passage 26a to the O _2, H 2 or an organic _compound, and the like.

Further, the pores may have a size that allows ions to pass through. For example, the lower limit of the diameter of the pores (diameter equivalent to a circle) is preferably 0.3 nm or more. Further, the area ratio S1 / S2 of the total area S1 of the plurality of pores and the area S2 of the ion permeable member 21a is 0.9 or less, preferably 0.6 or less so as not to impair the mechanical strength. Further, the shape of the pores is not limited to a circular shape, and may be an elliptical shape, a triangular shape, or a square shape. The arrangement of the pores is not limited to a square lattice, and may be a triangular lattice or random. Further, the pores may be filled with the ion exchange membrane 19. Examples of the ion exchange membrane include a cation exchange membrane such as Nafion or Flemion, and an anion exchange membrane such as Neosepta or Selemion. Further, the pores may be filled with a glass filter or agar.

The second electrode 11 may have a plurality of slits that penetrate from the front surface to the back surface and are filled with the ion exchange membrane 19 instead of the pores. The slit selectively allows only ions (for example, H ⁺ ) generated by the oxidation reaction of the first electrode 16 in the first electrolytic cell 25 to pass through the second electrolytic cell flow path 26a.

The second catalyst 18 is formed on the back surface of the second electrode 11. The second catalyst 18 is formed so as to be in contact with the ion transfer path. The second catalyst 18 is porous and allows the feedstock of the electrolyte, water (H ₂ O), CO ₂ and ions (eg H ⁺ ) to pass through. Further, a gas diffusion layer (not shown) may be formed between the second electrode 11 and the second electrolytic cell flow path 26a. The gas diffusion layer is porous and has water repellency. This increases the mass diffusion rate, water (H 2 _O) and CO ₂ can be supplied to the second catalyst 18 as a vapor (gas). As a result, the reaction efficiency of the second catalyst 18 can be increased.

The ion exchange membrane 19b is formed on the back surface of the second catalyst 18. The ion exchange membrane 19b selectively selects only ions (for example, H ⁺ ) generated by the oxidation reaction of the third electrode 51 in the third electrolytic cell flow path 27a via the second catalyst 18 in the second electrolytic cell flow path 26a. Let it pass through. Ions passed through the ion exchange membrane 19a is converted by the reduction reaction at the second electrode 11 of the second electrolytic cell 26 to the O _2, H 2 or an organic _compound, and the like. Examples of the ion exchange membrane 19b include a cation exchange membrane such as Nafion or Flemion, and an anion exchange membrane such as Neosepta or Selemion.

The third catalyst 52 is formed on the back surface of the ion exchange membrane 19b. The third catalyst 52 is porous and allows the feedstock of the electrolyte, water (H ₂ O), CO ₂ and ions (eg H ⁺ ) to pass through. Further, a gas diffusion layer (not shown) may be formed between the third electrode 51 and the third electrolytic cell flow path 27a. The gas diffusion layer is porous and has water repellency. This increases the mass diffusion rate, water (H 2 _O) and CO ₂ can be supplied to the third catalyst 52 as a vapor (gas). As a result, the reaction efficiency of the third catalyst 52 can be increased.

The third catalyst 52 is provided to enhance the chemical reactivity (oxidation reactivity) near the surface of the third electrode 51. When an aqueous solution, that is, a solution containing H ₂ O is used as the third electrolytic solution 23c, the third electrode 51 oxidizes H ₂ O to generate O ₂ and H ⁺ . Therefore, the third catalyst 52 is comprised of a material that reduces the activation energy for the oxidation of H 2 _O. In other words, it is composed of a material that reduces the overvoltage in oxidizing H ₂ O to produce O ₂ and H ⁺ . Such materials include dual metal oxides such as Mn-O, Ir-O, Ni-O, Co-O, Fe-O, Sn-O, In-O, or Ru-O, Ni-Co. Three-way metal oxides such as -O, Ni-Fe-O, La-Co-O, Ni-La-O, Sr-Fe-O, Pb-Ru-Ir-O, La-Sr-Co-O Such as quaternary metal oxides, or metal complexes such as Ru complex or Fe complex. The shape of the third catalyst is not limited to the thin film shape, but may be a lattice shape, a particle shape, or a wire shape.

The third electrode 51 is formed on the back surface of the third catalyst 52. The third electrode 51 is composed of, for example, a metal plate such as Cu, Al, Ti, Ni, Fe, or Ag, or an alloy plate containing at least one of them, such as SUS. Further, the third electrode 51 may be made of a conductive resin or the like. Further, the third electrode 51 may be made of a semiconductor substrate such as Si or Ge. Further, the third electrode 51 may be made of carbon or porous carbon.

The second electrolytic cell flow path 26a is formed in the second electrode 11. More specifically, the second electrolytic cell flow path 26a is formed as a groove formed on the back surface of the second electrode 11. In other words, the second electrolytic cell flow path 26a is formed in the hollow portion at the interface between the second electrode 11 and the second catalyst 18. Therefore, the second electrolytic cell flow path 26a is formed in contact with the second electrode 11 and the second catalyst 18. That is, when the second electrolytic cell 23b is filled in the second electrolytic cell flow path 26a, the second electrolytic cell 23b comes into contact with the second electrode 11 and the second catalyst 18.

The third electrolytic cell flow path 27a is formed in the third electrode 51. More specifically, the third electrolytic cell flow path 27a is formed as a groove formed on the surface of the third electrode 51. In other words, the third electrolytic cell flow path 27a is formed in the hollow portion at the interface between the third electrode 51 and the third catalyst 52. Therefore, the third electrolytic cell flow path 27a is formed in contact with the third electrode 51 and the third catalyst 52. That is, by filling the third electrolytic cell flow path 27a with the third electrolytic cell 23c, the third electrolytic cell 23c comes into contact with the third electrode 51 and the third catalyst 52.

The electrolytic cell control unit 61 includes a first electrolytic cell 23a in the first electrolytic cell 25, a second electrolytic cell 23b in the second electrolytic cell flow path 26a, and a third electrolytic cell 23c in the third electrolytic cell flow path 27a. To control. More specifically, the electrolytic cell control unit 61 includes the first electrolytic cell 23a in the first electrolytic cell 25, the second electrolytic cell 23b in the second electrolytic cell flow path 26a, and the third electrolytic cell flow path 27a. The amount of the third electrolytic cell 23c was measured, and the first electrolytic cell 23a by the pipe 22a, the second electrolytic cell 23b by the pipe not shown connected to the second electrolytic cell flow path 26a, and the third electrolytic cell flow path. The injection and discharge of the third electrolytic solution 23c are controlled by a pipe (not shown) connected to 27a.

3-2. Operation of the third embodiment FIG. 17 is a diagram showing the operation of the artificial photosynthesis system of the chemical reaction apparatus according to the third embodiment. Artificial photosynthesis systems are mainly used when there is surplus power and when there is solar energy.

As shown in FIG. 17, when used as an artificial photosynthesis system, the switching element control unit 41 turns off the first switching element 31 and the second switching element 33. As a result, the second electrode 11 and the third electrode 51 are electrically cut off via the external power supply 32. Further, the first electrode 16 and the second electrode 11 are electrically cut off via the power demand unit 34.

Further, the electrolytic solution control unit 61 controls the amount of the first electrolytic solution 23a in the first electrolytic cell 25 so that the first electrode 16 is immersed in the first electrolytic cell 23a. As a result, the first electrolytic cell 23a is injected into the first electrolytic cell 25 via the pipe 22a, and the inside of the first electrolytic cell 25 is filled with the first electrolytic cell 23a. The inside of the first electrolytic cell 25 does not have to be filled with the first electrolytic cell 23a, and at least a part of the first electrode 16 may be immersed in the first electrolytic cell 23a.

On the other hand, the electrolytic cell control unit 61 controls the amount of the second electrolytic cell 23b in the second electrolytic cell flow path 26a so that the second electrode 11 is immersed in the second electrolytic cell 23b. As a result, the second electrolytic cell 23b is injected into the second electrolytic cell flow path 26a via a pipe (not shown), and the inside of the second electrolytic cell flow path 26a is filled with the second electrolytic cell 23b. The inside of the second electrolytic cell flow path 26a does not have to be filled with the second electrolytic cell 23b, and at least a part of the second electrode 11 may be immersed in the second electrolytic cell 23b.

The third electrolytic cell flow path 27a may or may not be filled with the third electrolytic cell 23c.

When light is irradiated from above in this state, equation (1) is formed near the front surface of the first electrode 16 in contact with the first electrolytic solution 23a, and (2) is provided near the back surface of the second electrode 11 in contact with the second electrolytic solution 23b. The reaction of the formula occurs.

As shown in the equation (1), H ₂ O is oxidized (loses electrons) near the surface of the first electrode 16 to generate O ₂ and H ⁺ . Then, the H ⁺ generated on the first electrode 16 side moves to the second electrode 11 side. More specifically, the H ⁺ generated on the first electrode 16 side passes through the ion exchange membrane 19 and the porous second catalyst 18 and moves into the second electrolytic cell flow path 26a.

As shown in the equation (2), in the vicinity of the back surface of the second electrode 11 (second electrolytic cell flow path 26a), CO ₂ reacts with the moved H ⁺ to generate CO and H ₂ O. That is, CO ₂ is reduced (obtaining electrons).

As described above, in the artificial photosynthesis system, an electromotive force is generated in the photovoltaic layer 15 by solar energy, and the electromotive force causes a redox reaction (electrolytic reaction) on the front surface of the first electrode 16 and the back surface of the second electrode 11. It happens and chemical energy is generated. That is, solar energy can be converted into chemical energy.

FIG. 18 is a diagram showing the operation of the electrolytic system of the chemical reaction apparatus according to the third embodiment. Electrolytic systems are mainly used when there is surplus power and there is no solar energy. For example, an electrolytic system can be used at night.

As shown in FIG. 18, when used as an electrolytic system, the switching element control unit 41 turns on the first switching element 31. As a result, the second electrode 11 and the third electrode 51 are electrically connected via the external power supply 32. On the other hand, the switching element control unit 41 turns off the second switching element 33. As a result, the first electrode 16 and the second electrode 11 are electrically cut off via the power demand unit 34.

Further, the electrolytic cell control unit 61 controls the amount of the second electrolytic cell 23b in the second electrolytic cell flow path 26a so that the second electrode 11 is immersed in the second electrolytic cell 23b. As a result, the second electrolytic cell 23b is injected into the second electrolytic cell flow path 26a via a pipe (not shown), and the inside of the second electrolytic cell flow path 26a is filled with the second electrolytic cell 23b. The inside of the second electrolytic cell flow path 26a does not have to be filled with the second electrolytic cell 23b, and at least a part of the second electrode 11 may be immersed in the second electrolytic cell 23b.

On the other hand, the electrolytic cell control unit 61 controls the amount of the third electrolytic cell 23c in the third electrolytic cell flow path 27a so that the third electrode 51 is immersed in the third electrolytic cell 23c. As a result, the third electrolytic cell 23c is injected into the third electrolytic cell flow path 27a via a pipe (not shown), and the inside of the third electrolytic cell flow path 27a is filled with the third electrolytic cell 23c. The inside of the third electrolytic cell flow path 27a does not have to be filled with the third electrolytic cell 23c, and at least a part of the second electrode 11 may be immersed in the second electrolytic cell 23b.

The first electrolytic cell 25 may or may not be filled with the first electrolytic cell 23a.

When an electromotive force is generated in the external power supply 32 in this state, the equation (1) is in the vicinity of the front surface of the third electrode 51 in contact with the third electrolytic solution 23c, and (2) is in the vicinity of the back surface of the second electrode 11 in contact with the second electrolytic solution 23b. ) Equation reaction occurs.

As shown in the equation (1), H ₂ O is oxidized (loses electrons) near the surface of the third electrode 51 (third electrolytic cell flow path 27a) to generate O ₂ and H ⁺ . Then, the H ⁺ generated on the third electrode 51 side moves to the second electrode 11 side. More specifically, the H ⁺ generated on the third electrode 51 side passes through the porous third catalyst 52, the ion exchange membrane 19, and the porous second catalyst 18, and flows through the second electrolytic cell. Move into the road 26a.

At this time, since the third electrode 51 and the second electrode 11 are formed so as to face each other, the distance between them is relatively small. Therefore, the distance that H ⁺ moves from the third electrode 51 to the second electrode 11 is small. Therefore, H ⁺ can be efficiently diffused from the third electrode 51 to the second electrode 11.

As shown in the equation (2), in the vicinity of the back surface of the second electrode 11 (second electrolytic cell flow path 26a), CO ₂ reacts with the moved H ⁺ to generate CO and H ₂ O. That is, CO ₂ is reduced (obtaining electrons).

As described above, in the electrolytic system, an electromotive force is generated in the external power source 32 by the electric energy of the surplus electric power, and the oxidation-reduction reaction (electrolytic reaction) is caused by this electromotive force to generate chemical energy. That is, electrical energy can be converted into chemical energy.

The artificial photosynthesis system and the electrolysis system may be reacted at the same time. That is, the first electrolytic cell 25 is filled with the first electrolytic cell 23a, the second electrolytic cell flow path 26a is filled with the second electrolytic cell 23b, and the third electrolytic cell flow path 27a is filled with the third electrolytic cell 23c. Then, the switching element 31 is turned on while irradiating with light. As a result, the first electrolytic cell 25, the second electrolytic cell flow path 26a, and the third electrolytic cell flow path are connected in parallel to the second electrode 11 with the first electrode 16 and the third electrode 51. Each reaction can occur in each of 27a.

FIG. 19 is a diagram showing the solar cell operation of the chemical reaction apparatus according to the third embodiment. FIG. 20 is a diagram showing a modified example of the solar cell operation of the chemical reaction apparatus according to the second embodiment. Solar cells are mainly used when there is no surplus power.

As shown in FIG. 19, when used as a solar cell, the switching element control unit 41 turns off the first switching element 31. As a result, the second electrode 11 and the third electrode 51 are electrically cut off via the external power supply 32. On the other hand, the switching element control unit 41 turns on the second switching element 33. As a result, the first electrode 16 and the second electrode 11 are electrically connected via the power demand unit 34.

At this time, it is preferable that the movement of ions between the first electrode 16 and the second electrode 11 does not occur via the first electrolytic solution 23a or the second electrolytic solution 23b. That is, it is preferable that no current flows through the first electrolytic solution 23a or the second electrolytic solution 23b. This is because the photovoltaic power layer 15 discharges power to the power demand unit 34 at the same time as power generation. Therefore, the electrolytic solution control unit 61 controls the amount of the first electrolytic solution 23a in the first electrolytic cell 25 so that the first electrode 16 is not immersed in the first electrolytic cell 23a. Alternatively, the amount of the second electrolytic cell 23b in the second electrolytic cell 26a is controlled so that the second electrode 11 is not immersed in the second electrolytic cell 23b. As a result, the first electrolytic cell 23a is discharged from the first electrolytic cell 25 via the pipe 22a, and the inside of the first electrolytic cell 25 is filled with air, or a pipe (not shown) from the second electrolytic cell 26a. The second electrolytic cell 23b is discharged, and the inside of the second electrolytic cell 26a is filled with air.

The inside of the first electrolytic cell 25 does not have to be filled with air, and at least the first electrode 16 may not be immersed in the first electrolytic solution 23a. At this time, as shown in FIG. 20, a part of the first electrolytic cell 25 may be filled with the gas (for example, O ₂ or the like) generated by the artificial photosynthesis system or the electrolysis system described above. In this case, it is not necessary to discharge the first electrolytic solution 23a from the inside of the first electrolytic cell 25 via the pipe 22a. That is, it is not necessary to use a pump or the like provided in the pipe 22a, and energy loss can be reduced. Further, in this case, it is necessary to arrange the first electrode 16 on the side opposite to gravity.

Further, when the second electrode 11 is made of a conductive material, an insulating layer (not shown) may be provided between the second electrode 11 and the second catalyst 18 (contact point). Then, the second electrolytic cell 23b in the second electrolytic cell flow path 26a is discharged, and the inside of the second electrolytic cell flow path 26a is filled with an insulating liquid or gas. This eliminates the need to discharge the first electrolytic solution 23a in the first electrolytic cell 25. Therefore, the energy efficiency can be improved without the complexity associated with taking in and out the first electrolytic solution 23a.

When light is irradiated from above in this state, the irradiated light passes through the first electrode 16 and reaches the photovoltaic layer 15. When the photovoltaic layer 15 absorbs light, it generates electrons and holes paired with them, and separates them. That is, in each photovoltaic layer (first photovoltaic layer 12, second photovoltaic layer 13, and third photovoltaic layer 14), electrons are placed on the n-type semiconductor layer side (second electrode 11 side). Moves, and holes generated as a pair of electrons move to the p-type semiconductor layer side (first electrode 16 side), and charge separation occurs. As a result, an electromotive force is generated in the photovoltaic layer 15. The electromotive force generated by the photovoltaic layer 15 can supply electric power to the electric power demand unit 34.

As described above, in the solar cell, solar energy generates an electromotive force in the photovoltaic layer 15, and this electromotive force generates electric energy. That is, solar energy can be converted into electrical energy.

3-3. Effect of Third Embodiment According to the third embodiment, the same effect as that of the second embodiment can be obtained.

Further, according to the third embodiment, the third catalyst 53 and the third electrode 51 are formed on the back surface of the laminated body 10 (second catalyst 18) via the ion exchange membrane 19b. Then, the second electrolytic cell flow path 26a is formed inside the second electrode 11, and the third electrolytic cell flow path 27a is formed inside the third electrode 51. The second electrolytic cell flow path 26a and the third electrolytic cell flow path 27a in the third embodiment are formed to have smaller capacities than the second electrolytic cell 26 and the third electrolytic cell 27 in the second embodiment. As a result, the products produced in the second electrolytic cell flow path 26a and the third electrolytic cell flow path 27a can be recovered more easily than in the second embodiment.

3-4. Modification Example of Third Embodiment FIG. 21 is a schematic configuration diagram showing a configuration of a first modification of the chemical reaction apparatus according to the third embodiment.

As shown in FIG. 21, in the first modification of the chemical reaction apparatus according to the third embodiment, the sensor unit 42 is electrically connected between the first electrode 16 and the second electrode 11, and the second electrode is second. The sensor unit 43 is electrically connected between the electrode 11 and the third electrode 51.

The sensor unit 42 is electrically connected between the second electrode 11 and the third electrode 51 via a switching element 31 and an external power supply 32. In other words, the first switching element 31 is formed between the sensor unit 42 and the second electrode 11 or the third electrode 51. Then, by turning on the first switching element 31, the second electrode 11 and the third electrode 51 are electrically connected to each other via the external power supply 32 and the sensor unit 42. On the other hand, by turning off the first switching element 31, the second electrode 11 and the third electrode 51 are electrically cut off via the external power supply 32 and the sensor unit 42. That is, the sensor unit 42 functions when the chemical reaction apparatus is mainly used as an electrolytic system.

The sensor unit 43 is electrically connected between the first electrode 16 and the second electrode 11 via a third switching element 35. In other words, the third switching element 35 is formed between the sensor unit 43 and the first electrode 16 or the second electrode 11. Then, by turning on the third switching element 35, the first electrode 16 and the second electrode 11 are electrically connected via the sensor unit 43. On the other hand, by turning off the third switching element 35, the first electrode 16 and the second electrode 11 are electrically cut off via the sensor unit 43. That is, the sensor unit 43 functions when the chemical reaction apparatus is mainly used as an artificial photosynthesis system.

For example, in the case of an electrolytic system, the sensor unit 42 utilizes the electromotive force of the external power source 32, and by the reaction between the second electrolytic solution 23b and the second electrode 11 and the reaction between the third electrolytic solution 23c and the third electrode 51. Capture the resulting electrical signal. As a result, in the case of the electrolytic system, the sensor unit 42 has the pH of the second electrolytic solution 23b and the third electrolytic solution 23c, the concentrations of the second electrolytic solution 23b and the third electrolytic solution 23c, the second electrolytic solution 23b and the third electrolytic solution 23c. The composition of the electrolytic cell 23c, the pressure in the second electrolytic cell flow path 26a and the third electrolytic cell flow path 27a, the temperature in the second electrolytic cell flow path 26a and the third electrolytic cell flow path 27a, and the light intensity. Etc. are measured.

For example, in the case of an artificial photosynthesis system, the sensor unit 43 utilizes the electromotive force of the photovoltaic layer 15 to react between the first electrolytic solution 23a and the first electrode 16 and the second electrolytic solution 23b and the second electrode 11. It captures the electrical signal obtained by the reaction. As a result, in the case of the artificial photosynthesis system, the sensor unit 43 determines the pH of the first electrolytic solution 23a and the second electrolytic solution 23b, the concentrations of the first electrolytic solution 23a and the second electrolytic solution 23b, and the first electrolytic solution 23a and the second electrolytic solution 23b. 2 Measure the composition of the electrolytic cell 23b, the pressure in the first electrolytic cell 25 and the second electrolytic cell flow path 26a, the temperature in the first electrolytic cell 25 and the second electrolytic cell flow path 26a, the light intensity, and the like. To do. Since the sensor unit 43 utilizes the electromotive force of the photovoltaic layer 15, it can operate without a power source.

When used as an artificial photosynthesis system, it is conceivable that the sensor 43 does not function due to the electromotive force of the photovoltaic layer 15 due to its weak light intensity. In this case, the sensor unit 42 may be temporarily operated by the external power supply 32 to measure various requirements. On the other hand, the same applies when used as an electrolytic system. That is, when used as an electrolytic system, the sensor unit 43 may temporarily function by the electromotive force of the photovoltaic layer 15 to measure various requirements.

In the first modification, the sensors 42 and 43 determine the pH of the first electrolytic solution 23a, the second electrolytic solution 23b, and the third electrolytic solution 23c, the first electrolytic solution 23a, the second electrolytic solution 23b, and the third electrolytic solution 23b. Concentration of electrolytic cell 23c, composition of first electrolytic cell 23a, second electrolytic cell 23b, and third electrolytic cell 23c, in the first electrolytic cell 25, in the second electrolytic cell flow path 26a, and in the third electrolytic cell flow path. The pressure in 27a, the temperature in the first electrolytic cell 25, the second electrolytic cell flow path 26a, the temperature in the third electrolytic cell flow path 27a, the intensity of light, and the like are measured. As a result, the conditions of the electrolytic solution and the electrolytic cell for promoting the electrolytic reaction can be appropriately adjusted.

Although some embodiments of the present invention have been described, these embodiments are presented as examples and are not intended to limit the scope of the invention. These novel embodiments can be implemented in various other embodiments, and various omissions, replacements, and changes can be made without departing from the gist of the invention. These embodiments and modifications thereof are included in the scope and gist of the invention, and are also included in the scope of the invention described in the claims and the equivalent scope thereof.

10 ... Laminate, 11 ... 2nd electrode, 15 ... Photovoltaic layer, 16 ... 1st electrode, 21 ... Electrolytic cell, 23 ... Electrolyte, 31 ... 1st switching element, 32 ... External power supply, 33 ... Second Switching element, 34 ... Power demand unit, 41 ... Switching element control unit, 51 ... Third electrode, 61 ... Electrolyte solution control unit.

Claims (9)

In the operation method of the chemical reaction apparatus electrically connected to the electric power demand unit that stores or consumes electric power and the external power source that supplies electric power to the electric power demand unit.
Among the electric power supplied from the external power source to the electric power demand unit, the first step of confirming the presence or absence of surplus electric power exceeding the demand of the electric power demand unit, and
The second step to check for the presence of solar energy,
Equipped with
In the first step, when there is no surplus power, the amount of the electrolytic solution in the electrolytic cell is controlled so that at least one electrode in the electrolytic cell is not immersed in the electrolytic cell, and the photovoltaic layer. It functions as a first system that supplies electric power to the electric power demand unit through the electrode by the electromotive force in the above .
If there is surplus power in the first step, the process proceeds to the second step.
In the second step, when there is no solar energy, the amount of the electrolytic cell in the electrolytic cell is controlled so that the electrode in the electrolytic cell is immersed in the electrolytic cell, so that the surplus power is generated. To function as a second system that causes an oxidation-reduction reaction in the electrolytic solution in contact with the electrode .
In the second step, when the solar energy is present, the amount of the electrolytic solution in the electrolytic cell is controlled so that the electrode in the electrolytic cell is immersed in the electrolytic cell , and the light is generated. A method of operating a chemical reaction apparatus that functions as a third system that causes an oxidation-reduction reaction in the electrolytic solution in contact with the electrode by the electromotive force of the power layer. The method of operating a chemical reaction apparatus according to claim 1, wherein the electrolytic cell is filled with air or a non-conductive liquid when functioning as the first system. The method of operating a chemical reaction apparatus according to claim 1, wherein when the electrolytic cell functions as the first system, the electrolytic cell is filled with the gas generated by the second system or the third system. The electrode includes a first electrode arranged on the light irradiation side and a second electrode arranged on the side opposite to the light irradiation side.
The photovoltaic layer is electrically connected to the first electrode and the second electrode.
The external power supply is electrically connected between the first electrode and the second electrode via a first switching element.
The power demand unit is electrically connected between the first electrode and the second electrode in parallel with the external power supply via a second switching element.
The chemical reaction apparatus,
A switching element control unit for controlling on / off of the first switching element and the second switching element is provided.
By controlling the ON / OFF the first switching element and the second switching element by the switching element control unit, wherein the first system, the second system, and to claim 1 to function as either of the third system The method of operation of the chemical reactor described. 4. In the first step, when there is no surplus power, the switching element control unit turns off the first switching element and turns on the second switching element, thereby functioning as the first system. The operation method of the chemical reaction apparatus described in 1. The claim that when there is no solar energy in the second step, the switching element control unit turns off the second switching element and turns on the first switching element to function as the second system. The operation method of the chemical reaction apparatus according to 4. The fourth aspect of claim 4, wherein in the second step, when the solar energy is present, the switching element control unit turns off the first switching element and the second switching element, thereby functioning as the third system. How to operate the chemical reactor. The method of operating the chemical reaction apparatus according to claim 4, wherein the sensor unit is operated by the electromotive force of the external power source or the electromotive force of the photovoltaic layer. The eighth aspect of claim 8, wherein the sensor unit measures at least one of the pH of the electrolytic solution, the concentration of the electrolytic solution, the composition of the electrolytic solution, the pressure in the electrolytic cell, the temperature in the electrolytic cell, and the intensity of light. How to operate the chemical reactor.