WO2018116774A1

WO2018116774A1 - Carbon dioxide reduction apparatus

Info

Publication number: WO2018116774A1
Application number: PCT/JP2017/042933
Authority: WO
Inventors: 山口　仁
Original assignee: 株式会社デンソー
Priority date: 2016-12-22
Filing date: 2017-11-30
Publication date: 2018-06-28

Abstract

A carbon dioxide reduction apparatus is provided with photovoltaic elements (12), reduction electrodes (14) and reduction electrodes (14). Either the oxidation electrodes or the reduction electrodes are directly provided on the surface of the photovoltaic elements that is on the side opposite from the light-receiving surface and the other of the oxidation electrodes and reduction electrodes are provided at a distance from the photovoltaic elements. The light-receiving surfaces of the photovoltaic elements are not in direct contact with the electrolytic solution and can receive light from the light source without being mediated by the electrolytic solution. The reduction electrodes and the oxidation electrodes are in contact with the electrolytic solution.

Description

Carbon dioxide reduction equipment

Cross-reference of related applications

This application is based on Japanese Application No. 2016-249372 filed on Dec. 22, 2016 and Japanese Application No. 2017-161353 filed on Aug. 24, 2017. Is used.

The present disclosure relates to a carbon dioxide reduction device that reduces carbon dioxide.

Conventionally, a system that artificially synthesizes a carbon compound (for example, methanol) containing carbon by reducing the carbon dioxide by using the light energy of sunlight has been studied. Under these circumstances, a method of synthesizing a carbon compound by oxidizing water with an oxidation electrode and reducing carbon dioxide with a reduction electrode has been proposed (see, for example, Patent Document 1). Patent Document 1 discloses a configuration in which a laminated body in which a semiconductor and an electrode constituting a photovoltaic layer are laminated is immersed in an electrolytic solution.

Japanese Patent Laid-Open No. 2015-183218

However, in the configuration of Patent Document 1, since sunlight reaches the semiconductor through the electrolytic solution, the loss of light energy increases. In addition, since the electrode that performs the reduction reaction and the electrode that performs the oxidation reaction are connected to the semiconductor through an electrode stacked with the semiconductor, the heat generated during energy conversion in the semiconductor is effectively used for the oxidation reaction and the reduction reaction. I can't. For this reason, the production | generation efficiency of a carbon compound falls.

Further, in the configuration of Patent Document 1, the semiconductor is immersed in the electrolytic solution. For this reason, there exists a possibility that a semiconductor may corrode with electrolyte solution and durability may be impaired.

The present disclosure aims to provide a carbon dioxide reduction device capable of improving the generation efficiency of carbon compounds and improving the durability.

According to one aspect of the present disclosure, the carbon dioxide reduction device includes a photovoltaic element, a reduction electrode, and a reduction electrode. The photovoltaic element generates an internal photoelectric effect when irradiated with light. The reduction electrode is electrically connected to the photovoltaic device and generates a carbon compound by a reduction reaction of carbon dioxide. The oxidation electrode is electrically connected to the photovoltaic element, and generates oxygen and hydrogen ions by water oxidation reaction.

One of the oxidation electrode and the reduction electrode is directly provided on the surface of the photovoltaic element opposite to the light receiving surface, and the other electrode of the oxidation electrode and the reduction electrode is provided apart from the photovoltaic element. The light receiving surface of the photovoltaic device is not in direct contact with the electrolytic solution and can receive light from the light source without passing through the electrolytic solution, and the reduction electrode and the oxidation electrode are in contact with the electrolytic solution.

According to one aspect of the present disclosure, since the photovoltaic element that receives sunlight is disposed outside the electrolytic solution, light is directly irradiated to the photovoltaic element without being absorbed by the electrolytic solution. For this reason, the photovoltaic device can absorb light with high efficiency, and can increase the electrical energy generated by the photovoltaic device. Thereby, the production | generation efficiency of a carbon compound can be improved.

Also, by integrating the photovoltaic element and the oxidation electrode, the temperature of the electrolyte near the oxidation electrode can be increased using the heat generated by the photovoltaic element. In particular, by using a concentrating photovoltaic device, the heat generated by the semiconductor due to sunlight can be effectively used. Thereby, the oxidation reaction of water at the oxidation electrode can be promoted, and the production efficiency of the carbon compound can be improved.

Further, since the photovoltaic device is not in contact with the electrolytic solution, the photovoltaic device is not corroded by the electrolytic solution. Thereby, the durability of the carbon dioxide reduction device can be improved.

The above and other objects, features and advantages of the present disclosure will become more apparent from the following detailed description with reference to the accompanying drawings.
It is a front view of the carbon dioxide reduction device of a 1st embodiment. FIG. 2 is a sectional view taken along the line II-II in FIG. It is a front view of the carbon dioxide reduction device of a 2nd embodiment. FIG. 4 is a sectional view taken along line IV-IV in FIG. 3. It is a front view of the carbon dioxide reduction apparatus of a 3rd embodiment. FIG. 6 is a sectional view taken along line VI-VI in FIG. 5.

Hereinafter, embodiments of the present disclosure will be described with reference to the drawings. In the following embodiments, parts that are the same or equivalent to each other will be described with the same reference numerals.

(First embodiment)
The carbon dioxide reduction device 1 according to the first embodiment of the present disclosure will be described. The carbon dioxide reduction device 1 of the present embodiment is configured as an artificial photosynthesis device that performs oxygen generation, hydrogen generation, and carbon compound (such as methanol) generation by irradiating sunlight. In FIG. 1, the sun as a light source is located on the front side of the paper surface, and the direction from the front side of the paper surface toward the back side is the sunlight irradiation direction. In FIG. 2, the sun is positioned above the carbon dioxide reduction device 1, and the direction from the upper side to the lower side of the horizontal paper surface is the sunlight irradiation direction.

As shown in FIGS. 1 and 2, the carbon dioxide reduction device 1 includes

pipes

10 and 11. The

pipes

10 and 11 of the present embodiment have a square cross-sectional shape.

The

pipes

10 and 11 are capable of circulating an electrolytic solution therein, and the

pipes

10 and 11 constitute a container for containing the electrolytic solution. Although not shown, the electrolyte is supplied from the outside by a pump, for example, and circulates inside the

pipes

10 and 11. Although the kind of electrolyte solution is not specifically limited, In this embodiment, potassium hydrogencarbonate aqueous solution is used. The concentration of the aqueous potassium hydrogen carbonate solution is 0.1 mol / L. Hereinafter, the electrolytic solution may be referred to as “water” in the specification and drawings.

The

pipes

10 and 11 include a first pipe 10 and a second pipe 11. In the present embodiment, the first pipe 10 is an insulator, and the second pipe 11 is a conductor. Specifically, the 1st piping 10 is comprised from resin materials, such as PVC, CPVC, and PE, and the 2nd piping 11 is comprised from metal materials, such as aluminum and copper. Note that both the first pipe 10 and the second pipe 11 may be conductors, and an insulator may be provided between the first pipe 10 and the second pipe 11.

A plurality of first pipes 10 and second pipes 11 are provided. The plurality of first pipes 10 are arranged in parallel, and the plurality of second pipes 11 are arranged in parallel, respectively. The first pipe 10 and the second pipe 11 are stacked. In the present embodiment, the second pipe 11 is disposed closer to the light source than the first pipe 10.

1st piping 10 and 2nd piping 11 are arranged so that each longitudinal direction may intersect. In the present embodiment, a plurality of first pipes 10 and a plurality of second pipes 11 are arranged orthogonally in a grid pattern. For this reason, the plurality of first pipes 10 and the plurality of second pipes 11 are arranged so as to spread in a plane, can be handled like a plate-like member, and are uniformly generated and reacted in the entire carbon dioxide reduction device 1. Can be caused.

Further, since the plurality of first pipes 10 and the plurality of second pipes 11 intersect, there are a plurality of intersections where the first pipe 10 and the second pipe 11 intersect. The first pipe 10 and the second pipe 11 are in contact at the intersection. The first pipe 10 and the second pipe 11 are opened at portions that are in contact with each other at the intersection, and the inside of the first pipe 10 and the inside of the second pipe 11 communicate with each other at the intersection.

The carbon dioxide reduction device 1 is provided with a PV cell 12. The PV cell 12 is a solar cell that converts light energy into electrical energy using the photovoltaic effect. The PV cell 12 corresponds to the photovoltaic element of the present disclosure.

In the present embodiment, a group III-V semiconductor that is a direct transition type semiconductor is used as a semiconductor constituting the PV cell 12. The group III-V semiconductor of this embodiment has a tandem structure of two junctions or three junctions and is a tunnel junction. Such III-V semiconductors include GaInP / GaAs / Ge, GaInP / GaAs / GaNAs, GaInP / GaAs, AlGaInP / GaAs / Ge, AlGaInP / GaAs / GaNAs, AlGaInP / GaAs, AlGaAs / GaAs, AlGaAs / GaInNAs. AlGaInP / GaInNAs, a-SiGe / a-Si / a-Si, and a-SiGe / a-Si, each semiconductor forming a PN junction, and the substrate is a Ge substrate or a GaAs substrate. If there are two PN junctions, there are two junctions, and if there are three, there are three junctions. Further, a Si semiconductor may be used as the substrate of the III-V group semiconductor.

An oxidation electrode 13 and a reduction electrode 14 are connected to the PV cell 12. The oxidation electrode 13 is connected to the anode side of the PV cell 12, and the reduction electrode 14 is connected to the cathode side of the PV cell 12. The reduction electrode 14 is configured as a reaction electrode in which a reduction reaction of carbon dioxide is performed, and the oxidation electrode 13 is configured as a counter electrode. In the present embodiment, a plurality of sets of PV cells 12, oxidation electrodes 13, and reduction electrodes 14 are provided.

The oxidation electrode 13 is configured integrally with the PV cell 12 and is provided so as to be laminated with the PV cell 12. In FIG. 2, the upper surface of the PV cell 12 is a light receiving surface on which sunlight is irradiated. That is, in this embodiment, the cathode side of the PV cell 12 is a light receiving surface. The oxidation electrode 13 is provided on the surface opposite to the light receiving surface of the PV cell 12. As the oxidation electrode 13, for example, IrO ₂ , RuO ₂ , CoO, TiO _2, graphene, or the like may be used. These formed oxidation electrodes 13 also function as a protective film that suppresses corrosion of the semiconductor constituting the PV cell 12. Alternatively, the surface opposite to the light receiving surface of the PV cell 12 may be used as the oxidation electrode 13 as it is.

The PV cell 12 and the oxidation electrode 13 are provided in a portion facing the light source on the outer peripheral surface of the first pipe 10. The PV cell 12 is arranged so that the light receiving surface faces the sunlight side. The oxidation electrode 13 is disposed in contact with the first pipe 10, and the PV cell 12 is disposed on the side far from the first pipe 10.

The PV cell 12 is arranged in the first pipe 10 on the side far from the light source among the first pipe 10 and the second pipe 11. The PV cell 12 is arrange | positioned in the site | part which does not cross | intersect the 2nd piping 11 in the 1st piping 10 among the 1st piping 10 and the 2nd piping 11 arrange | positioned at grid | lattice form. In the present embodiment, the PV cell 12 is disposed between the two second pipes 11 in the first pipe 10. In the present embodiment, since the second pipe 11 is arranged closer to the light source than the first pipe 10, the PV cell 12 is sandwiched between the two second pipes 11.

The PV cell 12 is not in direct contact with the electrolytic solution, and is disposed to face the sun as a light source. The PV cell 12 need not have at least the light receiving surface in direct contact with the electrolytic solution. The portion of the first pipe 10 where the oxidation electrode 13 is provided is open, and the surface of the oxidation electrode 13 opposite to the PV cell 12 is in contact with the electrolyte inside the first pipe 10. The oxidation electrode 13 functions as a catalyst electrode that promotes the oxidation reaction of water. The first pipe 10 is an oxidation pipe in which an oxidation reaction of water using the oxidation electrode 13 is performed.

The reduction electrode 14 is configured as a separate body from the PV cell 12 and is disposed apart from the PV cell 12. As the reduction electrode 14, a metal such as Au, Cu, Pt, In, or Sn, a metal oxide such as Cu, In, Sn, or Ni, or graphene doped with nitrogen can be used. Graphene doped with nitrogen on a metal or metal oxide may be partially placed. Moreover, the 2nd piping 11 itself can also be used as the reduction electrode 14 by comprising the 2nd piping 11 with these materials.

The reduction electrode 14 is disposed inside the second pipe 11 and is in contact with the electrolytic solution inside the second pipe 11. The PV cell 12 and the second pipe 11 are connected by a wiring 15. The reduction electrode 14 is in contact with the inner wall surface of the second pipe 11, and the PV cell 12 and the reduction electrode 14 are connected by a wiring 15 through the second pipe 11 that is a conductor. The reduction electrode 14 functions as a catalyst electrode that promotes the reduction reaction of carbon dioxide. The second pipe 11 is a reducing pipe in which carbon dioxide is reduced using the reducing electrode 14.

An electrolyte membrane 16 is provided at the intersection of the first pipe 10 and the second pipe 11. The electrolyte membrane 16 is disposed at a portion where the first pipe 10 and the second pipe 11 communicate with each other, and is disposed between the oxidation electrode 13 of the first pipe 10 and the reduction electrode 14 of the second pipe 11. The electrolyte membrane 16 restricts movement of reaction products and the like while allowing movement of hydrogen ions in the electrolytic solution between the oxidation electrode 13 side and the reduction electrode 14 side. For example, Nafion (registered trademark of DuPont) can be used as the electrolyte membrane 16.

In the second pipe 11, a CO ₂ supply pipe 17 is inserted in the vicinity of the reduction electrode 14. Carbon dioxide is supplied from the CO ₂ supply pipe 17 to the reduction electrode 14 by bubbling. The bubble size of carbon dioxide is preferably from submicron to millimeter.

A condenser lens 18 is provided outside the first pipe 10 and the second pipe 11. The condensing lens 18 is provided corresponding to each of the plurality of PV cells 12. Specifically, one condenser lens 18 is provided for one PV cell 12, and the condenser lens 18 is disposed so as to face the light receiving surface of the PV cell 12. The condenser lens 18 is fixed to the

pipes

10 and 11. In addition, the condensing lens 18 can be made movable with respect to the

pipes

10 and 11 in order to cause the lens surface of the condensing lens 18 to follow the solar irradiation direction when the sunlight irradiation direction changes.

The condensing lens 18 has a function of concentrating sunlight on the PV cell 12. As the condenser lens 18, for example, a spherical lens, a Fresnel lens, a microlens array, or the like can be used.

In the present embodiment, the distance from the condenser lens 18 to the first pipe 10 is about 10 cm, and the focal point of the condenser lens 18 is about 10 cm. Thereby, the thickness of the whole carbon dioxide reducing device 1 becomes about 10 cm, and it becomes easy to install the carbon dioxide reducing device 1 on the roof or the roof of a building, for example.

By condensing sunlight with the condenser lens 18, the conversion efficiency from light energy to electrical energy in the PV cell 12 can be improved. In particular, the group III-V semiconductor used as the PV cell 12 in this embodiment has a great effect of improving the conversion efficiency by light collection.

In this embodiment, the magnification of the condenser lens 18 is 2 to 1000 times. The magnification of the condenser lens 18 can be adjusted by the refractive index, thickness, etc. of the condenser lens 18.

In the PV cell 12, when sunlight is irradiated, electron / hole pairs are generated by the internal photoelectric effect (photovoltaic effect). The holes generated in the PV cell 12 move to the oxidation electrode 13 and the electrons move to the reduction electrode 14.

The following oxidation reaction of water is performed on the surface of the oxidation electrode 13 to generate hydrogen ions and oxygen.

2H ₂ O + 4h ⁺ → 4H ⁺ + O ₂
Hydrogen ions generated at the oxidation electrode 13 pass through the electrolyte membrane 16 and move to the reduction electrode 14 side, and are used for the reduction reaction of carbon dioxide.

On the surface of the reduction electrode 14, the following carbon dioxide reduction reaction is performed, and a carbon compound (such as methanol) and hydrogen are generated.

CO ₂ + 6H ⁺ + 6e ⁻ → CH ₃ OH + H ₂ O
2H ^{+ +} 2e ^- → H ₂
In the PV cell 12, electrons are excited by the internal photoelectric effect when irradiated with sunlight, but a part of the light energy is released as heat. For this reason, the PV cell 12 generates heat when irradiated with sunlight. In this embodiment, since the PV cell 12 and the oxidation electrode 13 are integrated, the heat generated in the PV cell 12 is directly transmitted to the oxidation electrode 13. Thereby, the temperature of the oxidation electrode 13 rises, and the temperature of the electrolyte solution in contact with the oxidation electrode 13 rises.

In the present embodiment described above, since the PV cell 12 is disposed outside the electrolytic solution, sunlight is directly applied to the PV cell 12 without being absorbed by the electrolytic solution. For this reason, the PV cell 12 can absorb sunlight with high efficiency, and the electrical energy generated by the PV cell 12 can be increased. Thereby, the production | generation efficiency of a carbon compound can be improved.

Further, since the PV cell 12 is arranged outside the first pipe 10, the PV cell 12 is not in contact with the electrolytic solution, and the semiconductor constituting the PV cell 12 is not corroded by the electrolytic solution. Thereby, the durability of the carbon dioxide reduction device 1 can be improved.

Further, in this embodiment, by integrating the PV cell 12 and the oxidation electrode 13, wiring for connecting the PV cell 12 and the oxidation electrode 13 becomes unnecessary, and the loss of electric energy generated in the PV cell 12 is reduced. Can do.

Further, by integrating the PV cell 12 and the oxidation electrode 13, the temperature of the electrolyte near the oxidation electrode 13 can be increased by utilizing the heat generated in the PV cell 12. Thereby, the oxidation reaction of water at the oxidation electrode 13 can be promoted, and the generation efficiency of the carbon compound can be improved.

Further, in this embodiment, the electrolytic solution container is configured by combining a plurality of first pipes 10 and a plurality of second pipes 11. Thereby, the carbon dioxide reduction apparatus 1 can be made lightweight. Moreover, the reduction | restoration efficiency of the carbon dioxide per unit area can be made high, and the production | generation efficiency of a carbon compound can be improved.

Further, the plurality of first pipes 10 and the plurality of second pipes 11 are arranged in a lattice shape and are arranged so as to spread in a plane. For this reason, the carbon dioxide reduction apparatus 1 of this embodiment can be handled similarly to a plate-like member, and can be suitably installed, for example, on a roof of a building or a rooftop.

(Second Embodiment)
Next, a second embodiment of the present disclosure will be described. Hereinafter, description of the same parts as those in the first embodiment will be omitted, and only different parts will be described. 3 corresponds to FIG. 1 of the first embodiment, and FIG. 4 corresponds to FIG. 2 of the first embodiment.

As shown in FIGS. 3 and 4, in the second embodiment, unlike the first embodiment, the first pipe 10 in which the PV cells 12 are arranged is closer to the light source that is sunlight than the second pipe 11. Arranged on the side. For this reason, the PV cell 12 and the oxidation electrode 13 provided in the first pipe 10 are arranged closer to the light source than the second pipe 11. For this reason, unlike the said 1st Embodiment, the PV cell 12 arrange | positioned at the 1st piping 10 is not pinched | interposed between the two 2nd piping 11, and the 2nd piping 11 is a light source rather than the PV cell 12. Does not exist on the near side. Thereby, even if it is a case where the position of a light source changes, there is no possibility that the sunlight irradiated to the PV cell 12 may be interrupted by the nearby second pipe 11.

That is, according to the configuration of the second embodiment, the PV cell 12 can absorb sunlight with high efficiency regardless of the position of the light source, and the electrical energy generated by the PV cell 12 can be increased. .

(Third embodiment)
Next, a third embodiment of the present disclosure will be described. Hereinafter, description of the same parts as those in the above embodiments will be omitted, and only different parts will be described. 5 corresponds to FIG. 1 of the first embodiment, and FIG. 6 corresponds to FIG. 2 of the first embodiment.

As shown in FIGS. 5 and 6, in the third embodiment, as in the first embodiment, the first pipe 10 in which the PV cells 12 are arranged is arranged on the side farther from the light source than the second pipe 11. ing. For this reason, the PV cell 12 arranged in the first pipe 10 is sandwiched between the two second pipes 11, and the second pipe 11 exists closer to the light source than the PV cell 12.

In the third embodiment, an inclined surface 11 a that is inclined with respect to the stacking direction of the first pipe 10 and the second pipe 11 is provided on the second pipe 11 near the light source. The inclined surface 11a is provided to face the light source side. The inclined surface 11 a is provided so that the second pipe 11 does not shade the PV cell 12 regardless of the position of the light source that is sunlight. For this reason, the second pipe 11 has a smaller cross-sectional area on the side closer to the light source than on the side farther from the light source. The cross section of the second pipe 11 has a substantially trapezoidal shape, a substantially pentagonal shape, or a substantially triangular shape.

The inclined surface 11 a is provided continuously in the longitudinal direction of the second pipe 11, but may be provided at least at a site adjacent to the PV cell 12 provided in the first pipe 10. Further, the inclined surface 11a is not limited to a flat surface, and may be a curved surface that swells outward. In this case, the cross section of the inclined surface 11a second pipe 11 is arcuate.

According to the third embodiment, since the inclined surface 11a is provided on the side close to the light source in the second pipe 11, even if the position of the light source changes, the sunlight irradiated to the PV cell 12 Is not likely to be blocked by the nearby second pipe 11. For this reason, regardless of the position of the light source, the PV cell 12 can absorb sunlight with high efficiency, and the electrical energy generated by the PV cell 12 can be increased.

(Other embodiments)
The present disclosure is not limited to the above-described embodiment, and can be variously modified as follows without departing from the spirit of the present disclosure. Further, the means disclosed in each of the above embodiments may be appropriately combined within a practicable range.

(1) In each of the above-described embodiments, an example in which a plurality of the first pipes 10 and the second pipes 11 are provided has been described.

(2) In each of the above embodiments, an example in which a plurality of sets of the PV cell 12, the oxidation electrode 13, and the reduction electrode 14 are provided has been described.

(3) In each of the above embodiments, the electrolyte solution is circulated inside the first pipe 10 and the second pipe 11, but the electrolyte solution is housed inside the first pipe 10 and the second pipe 11. The electrolyte solution need not necessarily be circulated.

(4) In each of the above embodiments, the oxidation electrode 13 is provided integrally on the opposite side of the light receiving surface of the PV cell 12, and the reduction electrode 14 is connected to the PV cell 12 by a wiring 15. However, the reduction electrode 14 may be integrally provided on the opposite side of the light receiving surface of the PV cell 12, and the oxidation electrode 13 may be connected to the PV cell 12 by a wiring 15. In this case, the anode side of the PV cell 12 may be the light receiving surface.

Further, the PV cell 12 is disposed on the second pipe 11 side. Specifically, the PV cell 12 is a portion of the first pipe 10 and the second pipe 11 arranged in a lattice shape that does not intersect the first pipe 10 in the second pipe 11, It is arranged between one pipe 10.

Integrating the PV cell 12 and the reduction electrode 14 makes it possible to raise the temperature of the electrolyte near the reduction electrode 14 using the heat generated in the PV cell 12. Thereby, the reduction reaction of carbon dioxide at the reduction electrode 14 can be promoted, and the production efficiency of the carbon compound can be improved.

(5) In the configuration of each embodiment described above, a mediator may be included in the electrolyte solution on the reduction electrode 14 side. A mediator is a compound that mediates electron transfer through a carbon dioxide reduction reaction. A nitrogen-containing aromatic compound can be used as the mediator. The aromatic compound is a planar ring having a delocalized π electron system containing 4n + 2 (n is an integer) π electrons. Aromatic rings can be formed by 5, 6, 7, 8, 9, or 10 or more atoms. Aromatic compounds include monocyclic and fused ring polycyclic.

The nitrogen-containing aromatic compound is a heteroaromatic compound in which one or more constituent atoms of the aromatic ring are N atoms. In the nitrogen-containing aromatic compound, one or more hydrogen atoms bonded to the constituent atoms of the aromatic ring may be substituted with a linear or branched lower alkyl group, a hydroxy group, an amino group, or a pyridyl group. Examples of nitrogen-containing aromatic compounds constituting such mediators include imidazole, methylimidazole, dimethylimidazole, triazole, pyridine, and dimethylaminopyridine.

Claims

A photovoltaic element (12) that generates an internal photoelectric effect when irradiated with light; and
A reduction electrode (14) that is electrically connected to the photovoltaic element and generates a carbon compound by a reduction reaction of carbon dioxide;
An oxidation electrode (13) that is electrically connected to the photovoltaic element and generates oxygen and hydrogen ions by an oxidation reaction of water;
One of the oxidation electrode and the reduction electrode is directly provided on the surface of the photovoltaic element opposite to the light receiving surface, and the other electrode of the oxidation electrode and the reduction electrode is separated from the photovoltaic element. Provided,
The light receiving surface of the photovoltaic device is not in direct contact with the electrolytic solution and can receive light from the light source without going through the electrolytic solution, and the reduction electrode and the oxidation electrode are in contact with the electrolytic solution. Carbon reduction device.
A first pipe (10) through which the electrolyte can flow; and a second pipe (11) through which the electrolyte can flow;
The first pipe and the second pipe communicate with each other inside,
The carbon dioxide reduction device according to claim 1, wherein the oxidation electrode is in contact with the electrolytic solution in the first pipe, and the reduction electrode is in contact with the electrolytic solution in the second pipe.
The carbon dioxide reduction device according to claim 2, wherein an electrolyte membrane (16) that allows proton movement is provided at a site where the first pipe and the second pipe communicate with each other.
The carbon dioxide reduction device according to claim 2 or 3, wherein a CO 2 supply pipe (17) for supplying bubble-like carbon dioxide is provided inside the second pipe.
A plurality of the first pipes and the second pipes are provided, and the plurality of first pipes and the plurality of second pipes are arranged in parallel,
The longitudinal direction of the first pipe and the second pipe intersect each other, and the plurality of first pipes and the plurality of second pipes are arranged in a grid pattern. Carbon dioxide reduction device.
The said photovoltaic device is arrange | positioned in the site | part which does not cross | intersect the other piping in any one piping among the said 1st piping and the said 2nd piping arrange | positioned at the grid | lattice form. Carbon dioxide reduction device.
The carbon dioxide reducing device according to claim 6, wherein the photovoltaic element is disposed between two other pipes in the one pipe.
8. The pipe according to claim 2, wherein one of the first pipe and the second pipe on which the photovoltaic element is arranged is arranged on a side farther from the light source than the other pipe. Carbon dioxide reduction device.
The carbon dioxide reduction device according to claim 8, wherein an inclined surface (11a) is provided on a side of the other pipe close to the light source.
The one pipe | tube in which the said photovoltaic device was arrange | positioned among the said 1st piping and the said 2nd piping is arrange | positioned at the side closer to a light source rather than the other piping. Carbon dioxide reduction device.
The carbon dioxide reduction device according to any one of claims 1 to 10, further comprising a condensing lens (18) that condenses the light applied to the photovoltaic element at a predetermined magnification.
A plurality of the photovoltaic elements are provided,
The carbon dioxide reduction device according to claim 11, wherein the condenser lens is provided corresponding to each position of the plurality of photovoltaic elements.