JP2013023728A - Electrolytic cell, and device and method for producing gas - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electrolytic cell electrolyzing an electrolyte and capable of efficiently collecting generated bubbles.SOLUTION: An electrolytic cell includes at least one electrolytic electrode 7 and a sidewall part 17. The electrolytic electrode 7 configures a first inner surface of the electrolytic cell. The sidewall part 17 configures a second inner surface of the electrolytic cell, the second inner surface facing the first inner surface. The sidewall part 17 has a first level difference part 45 so that a distance between the first inner surface and the second inner surface becomes wider at an upper part of the electrolytic cell than at the bottom side part. The first level difference part 45 is provided such that, when an electrolyte is stored in the electrolytic cell to be electrolyzed and bubbles are generated from the first inner surface, the bubbles are convected in the electrolyte between a liquid level 41 and the first level difference part 45 due to the buoyancy of the bubbles.

Description

  The present invention relates to an electrolytic cell, a gas production apparatus, and a gas production method.

  In recent years, the use of renewable energy has been desired from the viewpoint of depletion of fossil fuel resources and the suppression of global warming gas emissions. There are a wide variety of renewable energy sources such as sunlight, hydropower, wind power, geothermal power, tidal power, and biomass. Among them, sunlight has a large amount of available energy, and there are geographical restrictions on other renewable energy sources. Because of the relatively small amount, early development and popularization of technology that can efficiently use energy from sunlight is desired.

  Possible forms of energy generated from sunlight include electrical energy produced using solar cells and solar thermal turbines, thermal energy by collecting solar energy in a heat medium, and other types of sunlight. Examples include storable fuel energy such as liquid fuel and hydrogen by substance reduction. Many solar cell technologies and solar heat utilization technologies have already been put into practical use, but the energy utilization efficiency is still low, and the cost of producing electricity and heat is still high. Technology development is underway. Furthermore, while these forms of electricity and heat can be used to supplement short-term energy fluctuations, it is extremely difficult to supplement long-term fluctuations such as seasonal fluctuations, It is a problem that there is a possibility that the operating rate of the power generation equipment may be reduced due to the increase in power generation. On the other hand, storing energy as a substance, such as liquid fuel and hydrogen, is extremely effective as a technology that efficiently supplements long-term fluctuations and increases the operating rate of power generation facilities. It is an indispensable technology to raise and reduce carbon dioxide emissions thoroughly.

  The types of fuel that can be stored are roughly divided into liquid fuels such as hydrocarbons, gaseous fuels such as biogas and hydrogen, solid pellets such as biomass-derived wood pellets and metals reduced by sunlight. it can. In terms of ease of infrastructure development and energy density, liquid fuel, gaseous fuel including hydrogen in terms of total utilization efficiency improvement with fuel cells, etc., solid fuel in terms of storability and energy density, Although each form has advantages and disadvantages, a hydrogen production technique by decomposing water with sunlight has attracted particular attention from the viewpoint that water that can be easily obtained as a raw material can be used.

As a method of producing hydrogen using solar energy using water as a raw material, platinum is supported on a photocatalyst such as titanium oxide, and this substance is put in water to perform light separation in a semiconductor, and an electrolytic solution. The water is decomposed directly at high temperature using the photolysis method by reducing protons and oxidizing water, or by using thermal energy such as a high-temperature gas furnace, or indirectly by coupling with redox of metals, etc. Pyrolysis method that uses the metabolism of microorganisms that use light such as algae, water electrolysis method that combines electricity generated by solar cells and water electrolysis hydrogen production equipment, photoelectric conversion used in solar cells Examples of the method include a photovoltaic method in which electrons and holes obtained by photoelectric conversion are used in a reaction by a hydrogen generation catalyst and an oxygen generation catalyst by supporting a hydrogen generation catalyst and an oxygen generation catalyst on the material. Among these, the one that has the possibility of producing a small hydrogen production device by integrating the photoelectric conversion unit and the hydrogen generation unit is considered to be a photolysis method, a biological method, a photovoltaic method, From the viewpoint of the conversion efficiency of solar energy, the photovoltaic method is considered to be one of the technologies closest to practical use.
So far, a hydrogen production apparatus has been disclosed in which hydrogen is generated by photoelectric conversion and electrolysis of an electrolytic solution using the photovoltaic power (for example, Patent Document 1). By using such a hydrogen production apparatus, solar energy can be efficiently stored as hydrogen.

  Further, in an apparatus that electrolyzes an electrolytic solution to generate hydrogen, hydrogen generated as bubbles in the electrolytic cell is moved together with the electrolytic solution to the bubble separation device, and after hydrogen is recovered, the electrolytic solution is again introduced into the electrolytic cell. Thus, hydrogen is recovered (for example, Patent Document 2).

Japanese Patent No. 4559438 JP 2007-84914 A

However, in a conventional apparatus for electrolyzing an electrolytic solution to generate bubbles, a bubble separation device is required, and the device needs to be enlarged.
This invention is made | formed in view of such a situation, and provides the electrolytic cell which can collect | recover efficiently the bubbles which electrolyzed the electrolyte solution and were generated.

  The present invention is an electrolytic cell having at least one electrode for electrolysis and a side wall, wherein the electrode for electrolysis constitutes a first inner surface of the electrolytic cell, and the side wall is formed on the first inner surface. Opposing the second inner side surface of the electrolytic cell, and the side wall part is a first step portion in which an interval between the first inner side surface and the second inner side surface is wider than the bottom side in the upper part of the electrolytic cell. The first stepped portion is formed between the liquid surface and the first stepped portion by the buoyancy of the bubbles when the electrolytic solution is accommodated in the electrolytic cell and electrolyzed to generate bubbles from the first inner surface. There is provided an electrolytic cell characterized in that bubbles are provided in a convection in an electrolytic solution.

According to the present invention, since the electrode for electrolysis constitutes the first inner surface of the electrolytic cell, when the electrolytic solution is electrolyzed to generate bubbles from the surface of the electrode for electrolysis, the generated bubbles are formed on the first inner surface. Along with or away from the first inner surface, the electrolyte solution can be levitated, the gas in the bubbles can be released into the gas phase from the electrolyte surface, and the generated gas can be recovered it can.
According to the present invention, the side wall portion that constitutes the second inner side surface of the electrolytic cell facing the first inner side surface has a larger distance between the first inner side surface and the second inner side surface than the bottom side in the upper part of the electrolytic cell. Among the bubbles generated from the surface of the electrode for electrolysis and floating along the first inner surface, the small bubbles that are not released from the liquid surface into the gas phase (the diameter of the bubbles is small, the surface Bubbles with high tension) can be convected in the electrolytic solution between the first step portion and the surface of the electrolytic solution. This makes it possible to increase the probability that small bubbles will collide and become large bubbles (bubbles with a large bubble diameter and low surface tension), and the gas in the bubbles can be released into the gas phase. The gas generated as bubbles on the surface of the electrode can be efficiently recovered. As a result, the generated gas can be efficiently recovered without providing a bubble separation device, and the device can be miniaturized.
Further, by providing the first step portion, it is possible to suppress small bubbles from flowing into the electrolytic cell deeper than the first step portion, and the small bubbles diffuse widely in the electrolytic solution and the inner wall of the electrolytic cell. Adsorption to the whole can be suppressed. As a result, bubbles generated by electrolysis of the electrolytic solution can be efficiently recovered. Further, the number of bubbles adsorbed on the surface of the electrode for electrolysis can be reduced, and the surface area of the electrode for electrolysis that causes an electrolysis reaction can be increased. Furthermore, it is possible to suppress an increase in the level of the electrolytic solution caused by the wide diffusion of small bubbles in the electrolytic solution, and to prevent the electrolytic solution from entering a pipe for collecting the generated gas. it can.

It is a schematic sectional drawing of the electrolytic cell of one Embodiment of this invention. It is a schematic sectional drawing of the electrolytic cell in dotted line AA of FIG. (A) is a schematic sectional drawing of the electrolytic cell in the dashed-dotted line BB of FIG. 1, (b) is a schematic sectional drawing of the electrolytic cell in the dashed-dotted line CC of FIG. It is a schematic sectional drawing of the electrolytic cell in the range E enclosed with the dashed-dotted line of FIG. (A)-(f) is a schematic sectional drawing of a part of electrolytic cell of one Embodiment of this invention, respectively. (A) And (b) is a schematic sectional drawing of the electrolytic cell of one Embodiment of this invention, respectively. It is a schematic top view of the gas manufacturing apparatus of one Embodiment of this invention. It is a schematic sectional drawing of the gas manufacturing apparatus in the dotted line FF of FIG. It is a schematic back view of the gas manufacturing apparatus of one Embodiment of this invention. It is a schematic sectional drawing of the gas manufacturing apparatus in the dashed-dotted line GG of FIG. It is a schematic sectional drawing of the gas manufacturing apparatus in the dashed-dotted line HH of FIG. It is a schematic sectional drawing of the gas manufacturing apparatus in the range J enclosed with the dotted line of FIG. It is a schematic sectional drawing of the gas manufacturing apparatus of one Embodiment of this invention. It is a schematic sectional drawing of the gas manufacturing apparatus of one Embodiment of this invention. It is a schematic sectional drawing of the gas manufacturing apparatus of one Embodiment of this invention. It is a schematic sectional drawing of the gas manufacturing apparatus of one Embodiment of this invention. It is a schematic sectional drawing of the gas manufacturing apparatus of one Embodiment of this invention. It is a schematic sectional drawing of the gas manufacturing apparatus of one Embodiment of this invention. It is a schematic sectional drawing of the gas manufacturing apparatus of one Embodiment of this invention. It is a schematic sectional drawing of a part of conventional electrolytic cell.

The electrolytic cell of the present invention is an electrolytic cell having at least one electrode for electrolysis and a side wall portion, and the electrode for electrolysis constitutes a first inner surface of the electrolytic cell, and the side wall portion has a first side surface. The second inner side surface of the electrolytic cell facing the inner side surface is configured, and the side wall portion has a first gap between the first inner side surface and the second inner side surface that is wider than the bottom side in the upper part of the electrolytic cell. The first step portion has an electrolyte solution stored in the electrolytic cell and electrolyzed to generate bubbles from the first inner surface, and the liquid level and the first step portion are generated by the buoyancy of the bubbles. It is characterized in that the air bubbles are provided so as to convect in the electrolyte solution.
In the present invention, the electrode for electrolysis is an electrode for electrolyzing an electrolytic solution with an applied voltage.
In this invention, a side wall part is a part which comprises the side wall of an electrolytic cell. The side wall of the electrolytic cell may be a side wall for storing the electrolytic solution in the electrolytic cell, or may be a side wall for partitioning the electrolytic solution in the electrolytic cell.
In the present invention, the inner surface of the electrolytic cell is a surface other than the bottom surface and the upper surface facing the bottom surface among the inner surfaces of the electrolytic cell.
In the present invention, the stepped portion is a stepped portion where a difference in height is generated on the surface.

In the electrolytic cell of the present invention, when the first step portion electrolyzes the electrolytic solution and generates bubbles from the first inner surface, the bubbles near the liquid surface of the electrolytic solution are deeper than the first step portion in the electrolytic bath. It is preferable to be provided so as to suppress the flow to
According to such a structure, it can suppress that the bubble generated from the electrode for electrolysis spread | diffuses widely in electrolyte solution, and adsorb | sucks to the whole inner wall of an electrolytic vessel.
In the electrolytic cell of the present invention, it is preferable that the first step portion includes a plurality of steps.
According to such a configuration, the bubbles can be floated at a plurality of steps, and the bubbles generated from the electrode for electrolysis can be further suppressed from being diffused widely in the electrolytic solution.

In the electrolytic cell of the present invention, the second inner surface is provided on the first surface, the first surface on the bottom side of the electrolytic cell, and more than the distance between the first surface and the first inner surface. Preferably, the first step portion is provided between the first surface and the second surface. The second surface has a narrow distance from the inner surface.
According to such a configuration, air bubbles can be convected within a range surrounded by the first inner surface, the first surface, the first stepped portion, and the electrolyte surface.
In the electrolytic cell of the present invention, the first surface preferably has hydrophilicity.
According to such a configuration, the flow of bubbles on the first surface can be made smooth.

In the electrolytic cell of the present invention, the side wall portion has a second stepped portion on the bottom side of the electrolytic cell of the first stepped portion, and the second inner side surface is a bottom surface of the electrolytic cell on the second surface. And has a third surface that is wider than the distance between the second surface and the first inner surface than the first inner surface, and the second step portion includes the second surface and the third surface. It is preferable that it was provided between.
According to such a configuration, the first step can be provided without reducing the amount of the electrolytic solution in the electrolytic cell. Moreover, the space | interval of a 1st inner surface and a 1st surface can be made small, the quantity of the electrolyte solution which the bubble between the liquid level of electrolyte solution and a 1st level | step difference can convect can be decreased, and a bubble is generated. The gas in the bubbles can be easily combined and released into the gas phase. Thereby, the gas in the bubble which convects in the electrolytic solution can be released into the gas phase earlier.
In the electrolytic cell of the present invention, the electrolytic cell includes a first electrolysis electrode and a second electrolysis electrode as the electrolysis electrode, and the first and second electrolysis electrodes electrolyze the electrolytic solution, respectively. It is preferable that the first gas and the second gas are generated.
According to such a configuration, the electrolytic solution can be electrolyzed to produce the first gas and the second gas.

In the electrolytic cell of the present invention, it is preferable that the first and second electrolysis electrodes are further provided with a partition wall provided in parallel and provided between the first electrolysis electrode and the second electrolysis electrode.
According to such a configuration, the electrolytic cell can be flattened, can be installed on the back side of the solar cell, and the first gas and the second gas can be separated and recovered by the partition wall. it can.
In the electrolytic cell of the present invention, the partition preferably includes an ion exchanger.
According to such a structure, the imbalance of the ion concentration which arises in electrolyte solution can be eliminated easily.
In the electrolytic cell of the present invention, it is preferable that one of the first gas and the second gas is hydrogen and the other is oxygen.
According to such a configuration, hydrogen serving as a fuel for the fuel cell can be produced.

In addition, the present invention includes the electrolytic cell of the present invention, a photoelectric conversion unit having a light receiving surface and a back surface thereof, and the first and second electrodes for electrolysis are provided in parallel on the back surface, and There is also provided a gas production apparatus provided to electrolyze an electrolytic solution using an electromotive force generated by receiving light by a photoelectric conversion unit to generate a first gas and a second gas, respectively.
According to the gas production apparatus of the present invention, the first and second electrolysis electrodes use the electromotive force generated when the photoelectric conversion unit receives light to electrolyze the electrolytic solution, and the first gas and the second gas are respectively Since it is provided to generate, the first gas can be generated on the surface of the first electrolysis electrode, and the second gas can be generated on the surface of the second electrolysis electrode.
Further, according to the gas production apparatus of the present invention, since the first electrolysis electrode and the second electrolysis electrode are provided on the back surface of the photoelectric conversion unit, light is incident on the light receiving surface of the photoelectric conversion unit without passing through the electrolytic solution. And absorption of incident light and scattering of incident light by the electrolytic solution can be prevented. As a result, the amount of incident light to the photoelectric conversion unit can be increased, and the light use efficiency can be increased.
Furthermore, according to the gas manufacturing apparatus of the present invention, since the first electrolysis electrode and the second electrolysis electrode are provided on the back surface of the photoelectric conversion unit, the light incident on the light receiving surface is the first and second electrolysis electrodes. , And the first gas and the second gas generated therefrom are not absorbed or scattered. As a result, the amount of incident light to the photoelectric conversion unit can be increased, and the light use efficiency can be increased.

In the gas manufacturing apparatus of the present invention, the photoelectric conversion unit receives light to generate an electromotive force between the light receiving surface and the back surface, and the first electrolysis electrode is electrically connected to the back surface of the photoelectric conversion unit. It is preferable that the second electrolysis electrode is provided so as to be electrically connected to the light receiving surface of the photoelectric conversion unit.
According to such a structure, the thing of a laminated structure can be utilized for a photoelectric conversion part.
In the gas manufacturing apparatus of the present invention, it is preferable to further include an insulating portion provided between the second electrolysis electrode and the back surface of the photoelectric conversion portion.
According to such a configuration, it is possible to prevent a leak current from being generated between the second electrolysis electrode and the back surface of the photoelectric conversion unit.

In the gas production apparatus of the present invention, it is preferable that the gas production apparatus further includes a first electrode that contacts the light receiving surface of the photoelectric conversion unit.
According to such a configuration, the internal resistance can be reduced.
The gas manufacturing apparatus of the present invention preferably further includes a first conductive portion that electrically connects the first electrode and the second electrolysis electrode.
According to such a structure, the light-receiving surface of a photoelectric conversion part and the 2nd electrode for electrolysis can be electrically connected.

In the gas manufacturing apparatus of the present invention, it is preferable that the first conductive portion is provided in a contact hole that penetrates the photoelectric conversion portion.
According to such a configuration, the wiring distance between the light receiving surface of the photoelectric conversion unit and the second electrolysis electrode can be shortened, and the internal resistance can be reduced.
In the gas manufacturing apparatus of the present invention, the insulating portion is provided so as to cover a side surface of the photoelectric conversion portion, and the first conductive portion is a part of the insulating portion and covers a side surface of the photoelectric conversion portion. Preferably provided above.
According to such a configuration, the first conductive portion can be provided with a small number of steps, and the manufacturing cost can be reduced.

In the gas manufacturing apparatus of the present invention, the insulating portion is provided so as to cover a side surface of the photoelectric conversion portion, and the second electrolysis electrode is a part of the insulating portion and covers the side surface of the photoelectric conversion portion. It is preferable that the first electrode is provided on the first electrode and is in contact with the first electrode.
According to such a configuration, the first electrode and the second electrolysis electrode can be electrically connected without providing the first conductive portion.
In the gas production apparatus of the present invention, it is preferable that the photoelectric conversion unit has a photoelectric conversion layer including a p-type semiconductor layer, an i-type semiconductor layer, and an n-type semiconductor layer.
According to such a configuration, an electromotive force can be generated by causing light to enter the photoelectric conversion unit.

In the gas manufacturing apparatus of the present invention, the photoelectric conversion unit receives a light to generate a potential difference between the first and second areas on the back surface of the photoelectric conversion unit, and the first area is electrically connected to the first electrolysis electrode. It is preferable that the second area is provided so as to be electrically connected to the second electrolysis electrode.
According to such a configuration, the electromotive force generated between the first area and the second area of the photoelectric conversion unit can be output to the first electrolysis electrode and the second electrolysis electrode.
The gas manufacturing apparatus of the present invention further includes an insulating portion provided between the first and second electrolysis electrodes and the back surface of the photoelectric conversion portion, and having openings on the first area and the second area. It is preferable.
According to such a configuration, an electromotive force generated when the photoelectric conversion unit receives light can be efficiently generated between the first area and the second area.

In the gas manufacturing apparatus of the present invention, the first area is provided so as to be electrically connected to the first electrolysis electrode via the third conductive part, and the second area is provided via the second conductive part. It is preferably provided so as to be electrically connected to the electrode for electrolysis.
According to such a configuration, it is possible to reduce ohmic loss when the electromotive force generated by the photoelectric conversion unit receiving light is output to the first electrolysis electrode and the second electrolysis electrode.
In the gas manufacturing apparatus of the present invention, the photoelectric conversion part is made of at least one semiconductor material having an n-type semiconductor part and a p-type semiconductor part, and one of the first and second areas is the n-type semiconductor part. It is preferable that the other part is a part of the p-type semiconductor part.
According to such a configuration, an electromotive force can be generated between the first and second areas on the back surface of the photoelectric conversion unit when the photoelectric conversion unit receives light.

In the gas production apparatus of the present invention, it is preferable that the gas production apparatus further includes a first substrate having translucency, and the photoelectric conversion unit is provided on the first substrate.
According to such a configuration, the photoelectric conversion unit can be formed on the first substrate.
In the gas production apparatus of the present invention, the photoelectric conversion unit includes a plurality of photoelectric conversion layers connected in series, and the plurality of photoelectric conversion layers generate electromotive force generated by receiving light in the first electrolysis electrode and the second electrolysis. It is preferable that it is provided so as to be supplied to the electrode.
According to such a configuration, a high voltage electromotive force can be easily output to the first and second electrolysis electrodes.

In the gas manufacturing apparatus of the present invention, each photoelectric conversion layer is preferably connected in series by a fourth conductive portion.
According to such a configuration, the photoelectric conversion layers can be provided side by side.
In the gas manufacturing apparatus of the present invention, the fourth conductive portion may include a translucent electrode provided on the light receiving surface side of the photoelectric conversion layer and a back electrode provided on the back surface side of the photoelectric conversion layer. preferable.
According to such a configuration, the photoelectric conversion layers can be provided side by side.

In the gas production apparatus of the present invention, one of the first electrolysis electrode and the second electrolysis electrode is a hydrogen generation unit that generates H ₂ from the electrolytic solution, and the other is oxygen generation that generates O ₂ from the electrolytic solution. The hydrogen generation part and the oxygen generation part are respectively a hydrogen generation catalyst that is a catalyst for the reaction that generates H ₂ from the electrolytic solution and an oxygen generation catalyst that is a catalyst for the reaction that generates O ₂ from the electrolytic solution. It is preferable to include.
According to such a configuration, hydrogen serving as a fuel for the fuel cell can be produced.
In the gas production apparatus of the present invention, it is preferable that at least one of the hydrogen generation part and the oxygen generation part is a porous conductor carrying a catalyst.
According to such a configuration, the catalyst area of the reaction in which hydrogen or oxygen is generated can be increased.

In the gas production apparatus of the present invention, the hydrogen generation catalyst preferably contains at least one of Pt, Ir, Ru, Pd, Rh, Au, Fe, Ni, and Se.
According to such a configuration, hydrogen can be efficiently generated from the electrolytic solution.
In the gas production apparatus of the present invention, it is preferable that the oxygen generation catalyst contains at least one of Mn, Ca, Zn, Co, and Ir.
According to such a configuration, oxygen can be efficiently generated from the electrolytic solution.
In the gas manufacturing apparatus of the present invention, it is preferable that a second substrate is further provided on the first electrolysis electrode and the second electrolysis electrode, and the second substrate includes the side wall portion.
According to such a configuration, the gas production apparatus can include an electrolytic cell in which the first and second electrolysis electrodes each constitute the first inner surface, and the second substrate constitutes the second inner surface.

Further, the present invention provides the gas production apparatus of the present invention so that the light receiving surface of the photoelectric conversion unit is inclined with respect to a horizontal plane, introduces an electrolyte into the gas production apparatus from the lower part of the gas production apparatus, By making light incident on the light receiving surface of the photoelectric conversion unit, a first gas and a second gas are generated from the first electrolysis electrode and the second electrolysis electrode, respectively. A gas production method for discharging two gases is also provided.
According to the gas production method of the present invention, the first gas and the second gas can be produced by making light incident on the light receiving surface of the photoelectric conversion unit.

  Hereinafter, an embodiment of the present invention will be described with reference to the drawings. The configurations shown in the drawings and the following description are merely examples, and the scope of the present invention is not limited to those shown in the drawings and the following description.

Diagram 1 of the electrolytic cell is a schematic cross-sectional view of the electrolytic cell of the present embodiment, FIG. 2 is a schematic cross-sectional view of the electrolytic cell in the dotted line A-A of FIG. 3A is a schematic cross-sectional view of the electrolytic cell taken along one-dot chain line BB in FIG. 1, and FIG. 3B is a schematic cross-sectional view of the electrolytic cell taken along one-dot chain line CC in FIG. Further, FIG. 4 is a schematic cross-sectional view of the electrolytic cell in a range E surrounded by an alternate long and short dash line in FIG.

The electrolytic cell 21 of the present embodiment is an electrolytic cell 21 having at least one electrode for electrolysis 7, 8 and a side wall portion 17, and the electrodes 7, 8 for electrolysis have a first inner side surface 42 of the electrolytic cell 21. The side wall portion 17 constitutes a second inner side surface 43 of the electrolytic cell 21 that opposes the first inner side surface 42, and the side wall portion 17 is formed at the upper part of the electrolytic cell 21 with the first inner side surface 42 and the second inner side surface 43. The first step portion 45 has a first step portion 45 that is wider than the bottom side with respect to the side surface 43. The first step portion 45 contains the electrolytic solution in the electrolytic cell 21 and electrolyzes bubbles from the first inner side surface 42. When generated, the bubbles are provided so that the bubbles convect in the electrolytic solution between the liquid surface 41 and the first step portion 45 by the buoyancy of the bubbles.
Hereinafter, the electrolytic cell 21 of this embodiment will be described.
In the electrolytic cell 21 of the present embodiment, for example, as shown in FIGS. 1 to 3, the first electrolysis electrode 8 and the second electrolysis electrode 7 are arranged in parallel on the first substrate with the partition wall 13 interposed therebetween. The electrolytic cell 21 can be formed by installing the substrate 14 on the first electrolysis electrode 8 and the second electrolysis electrode 7 and joining the first substrate 1 and the second substrate 14 with the sealing material 16. it can. Moreover, the water supply port 18, the 1st gas exhaust port 20, and the 2nd gas exhaust port 19 can be provided. Moreover, in order to apply a voltage to the 1st and 2nd electrodes 8 and 7, the wiring 52 and the terminal part 10 can be provided.
In addition, although illustrated about the electrolytic cell 21 using the 1st board | substrate 1 and the 2nd board | substrate 14 here, the electrolytic cell 21 which installed the electrode 8 and 7 for 1st and 2nd electrolysis in the box-type electrolytic cell, for example is shown. But you can.

1. Electrolysis Electrode The electrolytic cell 21 of the present embodiment has at least one electrolysis electrode. Further, the electrolytic cell 21 of the present embodiment can have both the first electrolysis electrode 8 and the second electrolysis electrode 7. Thus, the electrolytic solution in the electrolytic cell 21 can be electrolyzed by applying a voltage between the first electrolysis electrode 8 and the second electrolysis electrode. In addition, the electrolytic cell 21 may have a plurality of sets of first electrolysis electrodes 8 and second electrolysis electrodes 7.
Moreover, as the electrolytic cell 21 having one electrode for electrolysis in the present embodiment, for example, the first electrolytic electrode 8 is provided in the electrolytic cell 21, and the second electrolytic electrode is provided in the other electrolytic cell, This is an electrolytic cell in which the electrolytic solution in the electrolytic cell 21 and the electrolytic solution in another electrolytic cell are electrically connected by a salt bridge.

The first and second electrodes for electrolysis 8 and 7 can be provided so as to electrolyze the electrolytic solution stored in the electrolytic cell 21 to generate a first gas and a second gas, respectively. For example, the first electrolysis electrode 8 and the second electrolysis electrode 7 are provided so that a voltage can be applied between them. Also, the first and second electrolysis electrodes 8 and 7 can be electrically connected to the terminal portion 10 by the wiring 52, respectively. Thus, an external power source can be connected to the terminal portion 10, and a voltage can be applied between the first electrolysis electrode 8 and the second electrolysis electrode 7 by the external power source.
The electrolytic solution may include water, and one of the first gas and the second gas may be hydrogen and the other may be oxygen. As a result, water contained in the electrolyte can be electrolyzed to generate hydrogen and oxygen.

The first or second electrode 8 or 7 for electrolysis constitutes the first inner surface of the electrolytic cell 21. As a result, the first or second electrode for electrolysis 8, 7 can come into contact with the electrolytic solution stored in the electrolytic cell 21, and the electrolytic solution can be electrolyzed to generate bubbles.
The first or second electrolysis electrodes 8 and 7 can be provided on the first substrate 1. In this case, the first substrate 1 and the first or second electrolysis electrodes 8 and 7 form the side wall of the electrolytic cell 21. The 1st board | substrate 1 will not be specifically limited if it has the intensity | strength which can become the side wall of the electrolytic vessel 21. FIG. Moreover, the 1st or 2nd electrode for electrolysis 8 and 7 can also be provided on the inner surface of a box-shaped water tank. In this case, the side wall portion 17 that has the inner surface of the box-shaped water tank facing the first or second electrolysis electrode 8, 7 becomes the side wall portion 17.

  The first or second electrolysis electrodes 8 and 7 can be provided in parallel. As a result, the electrolytic cell 21 can be flattened, for example, it can be easily installed on the back surface of the solar cell, and the electrolytic solution can be electrolyzed by efficiently using the photovoltaic power of the solar cell. can do. For example, as shown in FIGS. 1 and 2, the first and second electrolysis electrodes 8 and 7 can be provided in parallel with the partition wall 13 therebetween.

At least one of the first electrolysis electrode 8 and the second electrolysis electrode 7 has a plurality of surfaces, each of which has a surface that can contact the strip-shaped electrolyte solution, and the long sides of the surfaces are adjacent to each other. It may be provided alternately. In this way, by providing the first electrolysis electrode 8 and the second electrolysis electrode 7, the distance between the portion where the reaction generating the first gas occurs and the portion where the reaction generating the second gas occurs is increased. It can be shortened, and the ion concentration imbalance generated in the electrolyte can be reduced. Moreover, the 1st gas and 2nd gas can be collect | recovered easily by making the surface which can contact electrolyte solution into strip | belt shape.
The first electrolysis electrode 8 and the second electrolysis electrode 7 preferably have corrosion resistance to the electrolytic solution and liquid shielding properties to the electrolytic solution. Thus, the first gas and the second gas can be generated stably. For example, a metal plate or a metal film having corrosion resistance against the electrolytic solution can be used for the first electrolysis electrode 8 and the second electrolysis electrode 7.

In addition, at least one of the first electrolysis electrode 8 and the second electrolysis electrode 7 is preferably a porous conductor carrying a catalyst. According to such a configuration, the surface area of at least one of the first electrolysis electrode 8 and the second electrolysis electrode 7 can be increased, and the first gas or the second gas can be generated more efficiently. Can do. Further, by using a porous conductor, it is possible to suppress a change in the potential of the current flowing through the first or second electrolysis electrode 8 or 7, and to generate the first gas or the second gas more efficiently. Can be made. In this case, the first electrolysis electrode 8 or the second electrolysis electrode 7 can also have a two-layer structure of a portion having a liquid shielding property against the electrolytic solution and a porous portion.
One of the first electrolysis electrode 8 and the second electrolysis electrode 7 may be a hydrogen generation unit, and the other may be an oxygen generation unit. In this case, one of the first gas and the second gas is hydrogen, and the other is oxygen.

2. Hydrogen generating part The hydrogen generating part is a part that generates H ₂ from the electrolytic solution, and can be either the first electrolysis electrode 8 or the second electrolysis electrode 7.
Further, the hydrogen generation part may include a catalyst (hydrogen generation catalyst) for a reaction in which H ₂ is generated from the electrolytic solution. Thereby, the reaction rate of the reaction in which H ₂ is generated from the electrolytic solution can be increased. The hydrogen generation part may consist only of a catalyst for the reaction in which H ₂ is generated from the electrolytic solution, or this catalyst may be supported on a support. The hydrogen generation part may be a porous conductor carrying a catalyst. This can increase the catalyst surface area. According to such a configuration, by applying a voltage between the first electrolysis electrode 7 and the second electrolysis electrode 8, hydrogen can be generated at a faster reaction rate.

The catalyst for the reaction of generating H ₂ from the electrolyte (hydrogen generation catalyst) is a catalyst that promotes the conversion of two protons and two electrons into one molecule of hydrogen, is chemically stable, and generates hydrogen overvoltage. Can be used. For example, platinum group metals such as Pt, Ir, Ru, Pd, Rh, and Au, which have catalytic activity for hydrogen, and alloys or compounds thereof, Fe, Ni, and Se that constitute the active center of hydrogenase that is a hydrogen-producing enzyme. An alloy or a compound, a combination thereof, or the like can be preferably used. Among them, a nanostructure containing Pt and Pt has a small hydrogen generation overvoltage and can be suitably used. Materials such as CdS, CdSe, ZnS, and ZrO ₂ whose hydrogen generation reaction is confirmed by light irradiation can also be used.

The hydrogen generating catalyst can be supported on the conductor. Examples of the conductor carrying the catalyst include metal materials, carbonaceous materials, and conductive inorganic materials.
As the metal material, a material having electronic conductivity and resistance to corrosion in an acidic atmosphere is preferable. Specifically, noble metals such as Au, Pt, Pd, metals such as Ti, Ta, W, Nb, Ni, Al, Cr, Ag, Cu, Zn, Su, Si, and nitrides and carbides of these metals, Examples of the alloy include stainless steel, Cu—Cr, Ni—Cr, and Ti—Pt. It is more preferable that the metal material contains at least one element selected from the group consisting of Pt, Ti, Au, Ag, Cu, Ni, and W from the viewpoint that there are few other chemical side reactions. These metal materials have a relatively small electric resistance, and can suppress a decrease in voltage even when a current is extracted in the surface direction. Further, when using a metal material having poor corrosion resistance in an acidic atmosphere such as Cu, Ag, Zn, etc., noble metals and metals having corrosion resistance such as Au, Pt, Pd, carbon, graphite, glassy carbon, A metal surface having poor corrosion resistance may be coated with a conductive polymer, a conductive nitride, a conductive carbide, a conductive oxide, or the like.

  As the carbonaceous material, a chemically stable and conductive material is preferable. Examples thereof include carbon powders and carbon fibers such as acetylene black, vulcan, ketjen black, furnace black, VGCF, carbon nanotube, carbon nanohorn, and fullerene.

Examples of the inorganic material having conductivity include In—Zn—O (IZO), In—Sn—O (ITO), ZnO—Al, Zn—Sn—O, SnO ₂ , and antimony oxide-doped tin oxide. .

  In addition, examples of the conductive polymer include polyacetylene, polythiophene, polyaniline, polypyrrole, polyparaphenylene, polyparaphenylene vinylene, and the like, and examples of the conductive nitride include carbon nitride, silicon nitride, gallium nitride, indium nitride, and nitride. Germanium, titanium nitride, zirconium nitride, thallium nitride, etc. are listed, and conductive carbides include tantalum carbide, silicon carbide, zirconium carbide, titanium carbide, molybdenum carbide, niobium carbide, iron carbide, nickel carbide, hafnium carbide, tungsten carbide. , Vanadium carbide, chromium carbide, and the like. Examples of the conductive oxide include tin oxide, indium tin oxide (ITO), and antimony oxide-doped tin oxide.

  The structure of the conductor supporting the hydrogen generation catalyst includes a plate shape, a foil shape, a rod shape, a mesh shape, a lath plate shape, a porous plate shape, a porous rod shape, a woven fabric shape, a nonwoven fabric shape, a fiber shape, and a felt shape. It can be used suitably. Further, a grooved conductor in which the surface of the felt-like electrode is pressure-bonded in a groove shape is preferable because the electric resistance and the flow resistance of the electrode liquid can be reduced.

3. Oxygen generating portion The oxygen generating portion is a portion that generates O ₂ from the electrolytic solution, and can be either the first electrolysis electrode 8 or the second electrolysis electrode 7.
Further, the oxygen generation unit may include a catalyst for a reaction in which O ₂ is generated from the electrolytic solution. Thereby, the reaction rate of the reaction in which O ₂ is generated from the electrolytic solution can be increased. Further, the oxygen generation part may consist only of a catalyst for the reaction that generates O ₂ from the electrolytic solution, or the catalyst may be supported on a carrier. The oxygen generation part may be a porous conductor carrying a catalyst. This can increase the catalyst surface area. Furthermore, the oxygen generation unit may include an oxygen generation catalyst, and the oxygen generation catalyst may include at least one of Mn, Ca, Zn, Co, and Ir. According to such a configuration, oxygen can be generated at a higher reaction rate by the voltage applied between the first electrolysis electrode 8 and the second electrolysis electrode 7.

The catalyst for the reaction of generating O ₂ from the electrolyte (oxygen generating catalyst) is a catalyst that promotes the conversion of two water molecules into one molecule of oxygen, four protons, and four electrons, and is chemically stable. In addition, a material having a small oxygen generation overvoltage can be used. For example, oxides or compounds containing Mn, Ca, Zn, Co, which are active centers of Photosystem II, which is an enzyme that catalyzes the reaction of generating oxygen from water using light, and platinum such as Pt, RuO ₂ , IrO ₂ It is possible to use compounds containing group metals, oxides or compounds containing transition metals such as Ti, Zr, Nb, Ta, W, Ce, Fe, Ni, and combinations of the above materials. Among these, iridium oxide, manganese oxide, cobalt oxide, and cobalt phosphate can be suitably used because they have low overvoltage and high oxygen generation efficiency.

The oxygen generating catalyst can be supported on the conductor. Examples of the conductor carrying the catalyst include metal materials, carbonaceous materials, and conductive inorganic materials. These explanations apply as long as there is no contradiction in the explanation of the hydrogen generation catalyst described in “2. Hydrogen generation section”.
When the catalytic activity of the hydrogen generating catalyst and the oxygen generating catalyst alone is small, a promoter can be used. Examples thereof include oxides or compounds of Ni, Cr, Rh, Mo, Co, and Se.

  The method for supporting the hydrogen generating catalyst and the oxygen generating catalyst can be applied directly to a conductor or semiconductor, PVD methods such as vacuum deposition, sputtering, and ion plating, dry coating methods such as CVD, The method can be appropriately changed depending on the material such as an analysis method. A conductive material can be appropriately supported between the photoelectric conversion unit and the catalyst. Also, when the catalytic activity for hydrogen generation and oxygen generation is not sufficient, the reaction surface area is increased by supporting it on porous materials such as metals and carbon, fibrous materials, nanoparticles, etc., and the hydrogen and oxygen generation rates are improved. It is possible to make it.

4). Side wall part The electrolytic cell 21 of this embodiment has the side wall part 17 which comprises the 2nd inner surface of the electrolytic cell 21 facing a 1st inner surface. When the electrolytic cell 21 of the present embodiment has both the first electrolysis electrode 8 and the second electrolysis electrode 7, it can have the side wall portions 17 corresponding to each.
The side wall part 17 has the 1st level | step-difference part 45 in which the space | interval of a 1st inner surface and a 2nd inner surface becomes wider in the upper part of the electrolytic cell 21 than a bottom side. More specifically, when the electrolytic cell 21 has a cross section as shown in FIG. 3, the second substrate 14 that is the side wall portion 17 can have the first step portion 45. Further, the distance a between the side wall portion 17 above the step portion 45 and the first or second electrolysis electrodes 8, 7 (the interval a between the first surface 47 and the first inner side surface 42) is lower than the step portion 45. This is wider than the distance b (the distance b between the second surface 48 and the first inner surface 42) between the side wall portion 17 and the first or second electrolysis electrode 8, 7. As a result, when the electrolytic solution stored in the electrolytic cell 21 is electrolyzed to generate bubbles from the first inner side surface 42, the electrolytic solution between the liquid level 41 and the first step portion 45 is caused by gas buoyancy. The bubble 12 can be convected. This will be described with reference to the drawings.

  FIG. 4 is a schematic cross-sectional view of the electrolytic cell in the range E surrounded by the one-dot chain line in FIG. 3, when the electrolytic cell 21 is filled with the electrolytic solution, and the electrolytic solution is electrolyzed with the electrode for electrolysis to generate bubbles. It is a schematic diagram. When a voltage is applied between the first electrolysis electrode 8 and the second electrolysis electrode 7, the electrolytic solution in the electrolytic cell 21 is electrolyzed, so that the first inner surface 42 of the first electrolysis electrode 8 The first gas is generated as bubbles 12, and the second gas is generated as bubbles 12 on the first inner surface 42 of the second electrolysis electrode 7. The bubbles 12 generated on the first inner side surface 42 float in the electrolyte along the first inner side surface 42 by the buoyancy, and the bubbles that rise to the vicinity of the liquid level 41 of the electrolyte solution Release into the gas phase. The released gas is discharged from the first gas discharge port 20 or the second gas discharge port 19 and can collect the first gas or the second gas. At this time, the gas in the bubble 12 having a relatively large diameter is easily released from the liquid surface of the electrolytic solution into the gas phase, but the gas in the bubble 12 having a relatively small diameter is easily discharged from the electrolyte solution. Bubbles may drift in the electrolyte without being released from the surface into the gas phase. The reason for this is not clear, but it is considered that the surface tension of bubbles having a relatively large diameter is relatively small, and the surface tension of bubbles having a relatively small diameter is relatively large.

When the bubbles 12 are generated from the first inner side surface 42, it is considered that the upward flow of the electrolyte flowing along the first inner side surface 42 is generated by the bubbles 12 floating along the first inner side surface 42. Further, it is considered that this upward flow is also generated when the electrode for electrolysis generates heat. Further, such an upward flow may be generated by a stirrer or the like in order to efficiently collect bubbles on the surface of the electrode for electrolysis.
The upward flow of the electrolytic solution is considered to change to a flow from the first inner side surface 42 side toward the second inner side surface 43 side in the vicinity of the liquid surface 41 of the electrolytic solution. Further, it is considered that the flow of the electrolytic solution changes to a flow toward the bottom of the electrolytic cell 21 in the vicinity of the first surface 47 of the second inner side surface 43, and then flows in the vicinity of the first stepped portion 45. It is thought that it flows toward the bottom of the cell and convects in the electrolytic cell 21.

Among the bubbles 12 generated from the first inner side surface 42 and floating near the liquid surface of the electrolytic solution, the bubbles having a relatively small diameter and in which the internal gas is not released into the gas phase ride on the flow of the electrolytic solution. It is considered that the gas flows in the electrolytic cell 21. However, when the electrolytic solution flows in the vicinity of the first stepped portion 45, the electrolytic solution flows from the first surface 47 side of the second inner side surface 43 toward the first inner side surface 42 side. It is thought that it floats by the buoyancy. Therefore, by providing the first step 45, the bubbles 12 can be lifted again without the bubbles 12 getting on the electrolyte flow toward the bottom of the electrolytic cell 21. It is considered that the bubbles 12 float near the liquid surface of the electrolytic solution and again ride on the flow of the electrolytic solution from the first inner side surface 42 side toward the second inner side surface 43 side.
Therefore, by providing the first step portion 45, the bubbles 12 can be convected in the electrolytic solution between the liquid surface 41 and the first step portion 45. Thereby, a plurality of bubbles can be combined in the electrolyte solution between the liquid surface 41 and the first step portion 45 to form a bubble having a relatively large diameter. The bubbles having a relatively large diameter can easily release the gas therein into the gas phase, and the released gas is discharged from the first gas discharge port 20 or the second gas discharge port 19 and the first gas. Alternatively, the second gas can be recovered.

  By these things, in the electrolytic cell 21 of this embodiment, 1st gas or 2nd gas can be collect | recovered efficiently. Moreover, it is possible to suppress the bubbles near the liquid surface 41 of the electrolytic solution from flowing into the electrolytic cell 21 deeper than the first stepped portion 45. Further, the amount of gas present as bubbles in the electrolytic solution can be reduced, and the rise in the liquid level of the electrolytic solution due to the generation of bubbles can be reduced. Thereby, it can suppress that electrolyte solution penetrate | invades into piping for discharging | emitting 1st gas or 2nd gas. Furthermore, since the amount of bubbles in the electrolytic solution can be reduced, the amount of bubbles adsorbed on the first or second electrolysis electrodes 8 and 7 can also be reduced. Accordingly, the first gas or the second gas can be efficiently generated on the surface of the first or second electrolysis electrode 8 or 7.

Next, a case where bubbles are generated from the surface of the electrode for electrolysis using an electrolytic cell not having the first step portion 45 will be described. FIG. 20 is a schematic view when an electrolytic bath not having the first step portion is filled with the electrolytic solution, and the electrolytic solution is electrolyzed by the electrode for electrolysis to generate bubbles, and corresponds to FIG.
When bubbles are generated from the surface of the electrode 107 for electrolysis, the bubbles rise to the liquid level of the electrolyte, relatively large bubbles release the internal gas into the gas phase, and relatively small bubbles Ride through the flow and flow through the electrolytic cell. In an electrolytic cell that does not have the first step 45, an upward flow is generated along the inner surface formed by the electrolysis electrode 107, and a downward flow is generated along the inner surface facing the inner surface. Since relatively small bubbles flow along this downward flow, they diffuse throughout the electrolytic cell. For this reason, the bubbles diffused throughout the electrolytic cell are widely adsorbed on the inner surface of the electrolytic cell. As a result, the amount of bubbles in the electrolytic solution increases, and the recovery efficiency of the gas generated from the electrolysis electrode 107 decreases. Further, the increase in the amount of bubbles in the electrolytic solution increases the rise in the liquid level of the electrolytic solution due to the generation of bubbles. This increases the probability that the electrolyte enters the piping for discharging the first gas or the second gas. Furthermore, the amount of bubbles adsorbed on the surface of the electrode for electrolysis increases, and the gas generation efficiency on the surface of the electrode for electrolysis decreases.
Therefore, by providing the first step portion 45 on the side wall portion 17 as in the electrolytic cell 21 of the present embodiment, such a decrease in gas recovery efficiency can be suppressed, and an increase in the electrolyte level is suppressed. It is possible to suppress a decrease in gas generation efficiency on the surface of the electrode for electrolysis.

The side wall portion 17 is not particularly limited as long as it constitutes the second inner side surface 43 of the electrolytic cell 21 facing the first inner side surface 42 and has the first stepped portion 45. Moreover, the side wall part 17 may be comprised from one member, and may be comprised from several members. The side wall part 17 may be comprised from the 2nd board | substrate 14 which has the 1st level | step-difference part 45 like FIG.
FIGS. 5A to 5F are schematic sectional views of a part of the electrolytic cell 21 of the present embodiment, and correspond to FIG.

  The first step portion 45 includes a step in which the space between the first inner side surface 42 and the second inner side surface 43 is wider than the bottom side at the upper part of the electrolytic cell 21, and electrolyzes the electrolytic solution to form the first inner side surface 42. Is not particularly limited as long as it is provided so that bubbles are convected in the electrolyte solution between the liquid surface 41 and the first stepped portion 45 due to the buoyancy of the bubbles. 3. It may be a part including a step provided between the substantially parallel first surface 47 and second surface 48 of the side wall portion 17 as shown in FIGS.

  For example, as shown in FIG. 5A, the first step portion 45 includes a first surface 47 whose distance from the first inner surface 42 becomes wider toward the upper side, and a second surface substantially parallel to the first inner surface 42. It may be a portion including a step provided between the surface 48. This makes it easier for the bubbles to rise on the first surface 47.

  For example, as shown in FIG. 5B, the first step portion 45 is a surface that is inclined so as to approach the bottom of the electrolytic cell 21 as the surface formed by the step approaches the first surface 47. It may be a part including a step. This makes it easier for the bubbles that have flowed in the vicinity of the first step portion 45 on the flow of the electrolyte to rise due to the buoyancy, and the bubbles are located between the liquid surface 41 of the electrolyte and the first step portion 45. It is possible to facilitate convection in the electrolytic solution.

  For example, the first step portion 45 may be a portion including a plurality of steps as shown in FIG. As a result, the bubbles that have flowed in the vicinity of the first stepped portion 45 along the flow of the electrolyte can be lifted by the plurality of steps, and the bubbles are located between the liquid surface of the electrolyte and the first stepped portion 45. It is possible to facilitate convection in the electrolyte solution.

For example, as illustrated in FIG. 5D, the side wall portion 17 may be configured by the second substrate 14 and the hydrophilic member 50, and the first stepped portion 45 is the first surface configured by the hydrophilic member 50. It may be a portion including a step provided between 47 and the second surface 48 constituted by the second substrate 14. As a result, the first surface 47 of the side wall portion 17 can be made hydrophilic, and the flow of bubbles on the first surface can be made smooth. As the hydrophilic member 50, for example, a hydrophilic polymer such as polyalkylene glycol (PEG, etc.), polyacrylamide, dextran, pullulan, ficoll, etc. is coated on the first surface by a method such as dip coating, spray coating, spin coating or the like. The member formed by this is mentioned. Moreover, what adhered the sheet | seat which consists of these hydrophilic polymers on the 1st surface may be used.
Further, a member made of a hydrophilic material may be attached to the second substrate 14 to form the first step portion 45 and the first surface 47.
Further, even when the first surface 47 is not made of a hydrophilic member, the same effect is produced even when the surface treatment is performed so that the first surface 47 is hydrophilic. Therefore, the side wall portion 17 included in the electrolytic cell 21 of the present embodiment may be one in which the first surface 47 is subjected to a hydrophilic treatment. Examples of a method for hydrophilizing the first surface 47 include a method of generating a hydrophilic group on the first surface 47 by plasma processing.
In addition, it is preferable that the surface formed by the first step portion 45 does not have hydrophilicity. Thereby, it is possible to suppress the bubbles from flowing smoothly on this surface and flowing toward the bottom of the electrolytic cell 21.

  The first step portion 45 may be a portion including a step provided between the first surface 47 and the second surface 48 which are curved surfaces, for example, as shown in FIGS. . Further, the surface formed by the steps included in the first step portion 45 may be a curved surface. As a result, the flow of the electrolyte solution in the vicinity of the first surface and the vicinity of the first step portion 45 can be made smooth, so that the turbulent flow of the electrolyte solution can be suppressed, and the bubbles are first generated by the turbulent flow. Diffusion into the electrolytic cell 21 deeper than the step 45 can be suppressed.

Moreover, Fig.6 (a) (b) is a schematic sectional drawing of the electrolytic cell 21 of this embodiment, respectively.
The side wall part 17 may have a second step part 46 on the bottom side of the electrolytic cell 21 of the first step 45. The second inner surface is provided on the bottom side of the electrolytic cell 21 on the second surface 48, and the distance between the first inner surface 42 and the distance b between the second surface 48 and the first inner surface 42. You may have the 3rd surface 49 where c is wide. The second stepped portion 46 may be provided between the second surface 48 and the third surface 49. Thus, the first step 45 can be provided without reducing the amount of the electrolytic solution in the electrolytic cell 21. Further, the distance a between the first inner surface 42 and the first surface 47 can be reduced, and the amount of the electrolytic solution convected by the bubbles 12 between the liquid surface 41 of the electrolytic solution and the first step 45 can be reduced. It is possible that the bubbles 12 are combined and the gas in the bubbles is easily released into the gas phase. Thereby, the gas in the bubble which convects in the electrolytic solution can be released into the gas phase earlier.
Further, the interval a between the first surface 47 and the first inner side surface 42 may be narrower than the interval c between the third surface 49 and the first inner side surface 42. As a result, the amount of the electrolytic solution convected by the bubbles 12 between the liquid surface 41 of the electrolytic solution and the first step 45 can be reduced without reducing the amount of the electrolytic solution in the electrolytic cell 21. 12 can be combined, and the gas in the bubbles can be more easily released into the gas phase.

  Note that the first step 45 and the second step 46 of the side wall portion 17 may be formed by processing one member, for example, the second substrate 14 as shown in FIG. 6A, as shown in FIG. Thus, a plurality of members, for example, the second substrate 14 and the step member 51 may be formed.

  The second substrate 14 constitutes the electrolyte chamber 15 and needs to be able to confine the generated first gas and second gas, and a highly confidential substance is required. It is not particularly limited whether it is transparent or opaque, but it is preferably a transparent material in that it can be visually confirmed that the first gas and the second gas are generated. . The transparent second substrate is not particularly limited, and examples thereof include a transparent rigid material such as quartz glass, Pyrex (registered trademark), and a synthetic quartz plate, a transparent resin plate, and a transparent resin film. Among them, it is preferable to use a glass material because it is a gas that is not chemically permeable and is chemically and physically stable.

5. Partition Wall When the electrolytic cell 21 of the present embodiment has the first electrolysis electrode 8 and the second electrolysis electrode 7 and these are provided in parallel, the electrolytic cell 21 has the first electrolysis electrode 8 and the second electrolysis electrode. A partition wall 13 can be provided between the electrode 7 for use.
The partition wall 13 is an electrolytic solution chamber 15 that is a space between the first electrolysis electrode 8 and the second substrate 14 and an electrolytic solution chamber that is a space between the second electrolysis electrode 7 and the second substrate 14. 15 can be provided to partition. When at least one of the first electrolysis electrode 8 and the second electrolysis electrode 7 is provided, the partition walls 13 can be provided so as to be arranged in parallel. As a result, the first gas and the second gas generated by the first electrolysis electrode 8 and the second electrolysis electrode 7 can be prevented from mixing, and the first gas and the second gas can be separated. It can be recovered.
The partition wall 13 may include an ion exchanger. As a result, the ions are unbalanced by the electrolytic solution in the space between the first electrolysis electrode 8 and the second substrate 14 and the electrolytic solution in the space between the second electrolysis electrode 7 and the second substrate 14. The concentration can be kept constant.

For the partition wall 13, for example, an inorganic film such as porous glass, porous zirconia, or porous alumina or an ion exchanger can be used.
As the ion exchanger, any ion exchanger known in the art can be used, and a proton conductive membrane, a cation exchange membrane, an anion exchange membrane, or the like can be used.
The material of the proton conductive film is not particularly limited as long as it is a material having proton conductivity and electrical insulation, and a polymer film, an inorganic film, or a composite film can be used.

  Examples of the polymer membrane include Nafion (registered trademark) manufactured by DuPont, Aciplex (registered trademark) manufactured by Asahi Kasei Co., and Flemion (registered trademark) manufactured by Asahi Glass Co., Ltd., which are perfluorosulfonic acid electrolyte membranes. Examples thereof include membranes and hydrocarbon electrolyte membranes such as polystyrene sulfonic acid and sulfonated polyether ether ketone.

  Examples of the inorganic film include films made of phosphate glass, cesium hydrogen sulfate, polytungstophosphoric acid, ammonium polyphosphate, and the like. Examples of the composite membrane include a membrane made of a sulfonated polyimide polymer, a composite of an inorganic material such as tungstic acid and an organic material such as polyimide, and specifically, Gore Select membrane (registered trademark) or pores manufactured by Gore. Examples thereof include a filling electrolyte membrane. Furthermore, when used in a high temperature environment (for example, 100 ° C. or higher), sulfonated polyimide, 2-acrylamido-2-methylpropanesulfonic acid (AMPS), sulfonated polybenzimidazole, phosphonated polybenzimidazole, sulfuric acid. Examples include cesium hydrogen and ammonium polyphosphate.

The cation exchange membrane may be any solid polymer electrolyte that can move cations. Specifically, fluorine ion exchange membranes such as perfluorocarbon sulfonic acid membranes and perfluorocarbon carboxylic acid membranes, polybenzimidazole membranes impregnated with phosphoric acid, polystyrene sulfonic acid membranes, sulfonated styrene / vinylbenzene copolymers Examples include membranes.
When the anion transport number of the supporting electrolyte solution is high, it is preferable to use an anion exchange membrane. As the anion exchange membrane, a solid polymer electrolyte capable of transferring anions can be used. Specifically, a polyorthophenylenediamine film, a fluorine-based ion exchange film having an ammonium salt derivative group, a vinylbenzene polymer film having an ammonium salt derivative group, a film obtained by aminating a chloromethylstyrene / vinylbenzene copolymer, etc. Can be mentioned.

6). Sealing material The sealing material 16 bonds the first substrate 1 and the second substrate 14, and the first gas and the second gas generated from the electrolytic solution in the electrolytic cell 21 and the first and second electrolysis electrodes 8 and 7. It is a material for sealing. When a box-shaped substrate is used for the second substrate 14, a sealing material 16 is used for bonding the box and the first substrate 1. As the sealing material 16, for example, an ultraviolet curable adhesive, a thermosetting adhesive, or the like is preferably used, but the type thereof is not limited. The UV curable adhesive is a resin that undergoes polymerization upon irradiation with light having a wavelength of 200 to 400 nm and undergoes a curing reaction within a few seconds after light irradiation, and is divided into a radical polymerization type and a cationic polymerization type. Examples of the polymerization type resin include acrylates, unsaturated polyesters, and examples of the cationic polymerization type include epoxy, oxetane, and vinyl ether. Examples of the thermosetting polymer adhesive include organic resins such as phenol resin, epoxy resin, melamine resin, urea resin, and thermosetting polyimide. The thermosetting polymer adhesive is heated and polymerized in a state where pressure is applied at the time of thermocompression bonding, and then cooled to room temperature while being pressurized. I don't need it. In addition to the organic resin, a hybrid material having high adhesion to the glass substrate can be used. By using a hybrid material, mechanical properties such as elastic modulus and hardness are improved, and heat resistance and chemical resistance are dramatically improved. The hybrid material is composed of inorganic colloidal particles and an organic binder resin. For example, what is comprised from inorganic colloidal particles, such as a silica, and organic binder resin, such as an epoxy resin, a polyurethane acrylate resin, and a polyester acrylate resin, is mentioned.

  Here, the sealing material 16 is described, but it is not limited as long as it has a function of bonding the first substrate 1 and the second substrate 14, and a member such as a screw is externally used using a resin or metal gasket. It is also possible to appropriately use a method of applying pressure physically to increase confidentiality.

7). Electrolyte Chamber The electrolyte chamber 15 can be a space between the first electrolysis electrode 8 and the second substrate 14 and a space between the second electrolysis electrode 7 and the second substrate 14. Further, the electrolyte chamber 15 can be partitioned by the partition wall 13.
For example, a pump or a fan that circulates the electrolyte in the electrolyte chamber 15 so that the generated bubbles of the first gas and the second gas are efficiently separated from the first electrolysis electrode 8 or the second electrolysis electrode 7. It is also possible to provide a simple device such as a heat convection generator.

8). Water supply port, first gas discharge port, second gas discharge port, first gas discharge channel and second gas discharge channel The water supply port 18 is a part of the sealing material 16 included in the electrolytic cell 21 or the second substrate 14. It can be provided by making an opening in a part or the like. The water supply port 18 is arranged to replenish the electrolytic solution that has been decomposed into the first gas and the second gas, and the location and shape of the water supply port 18 can even be efficiently supplied to the electrolytic cell 21 as the raw material electrolytic solution. For example, there is no particular limitation.

  The first gas outlet 20 can be provided close to the upper end of the surface of the first electrolysis electrode 8 that can come into contact with the electrolytic solution. The second gas discharge port 19 can be provided close to the upper end of the surface of the second electrolysis electrode 7 that can come into contact with the electrolytic solution.

  Moreover, the 1st gas exhaust port 20 can be connected with a 1st gas exhaust path, and the 2nd gas exhaust port 19 can be connected with a 2nd gas exhaust path. In addition, the first gas discharge path can be connected to the plurality of first gas discharge ports 20, and the second gas discharge path can be connected to the plurality of second gas discharge ports 19. Thereby, the first gas and the second gas generated in the electrolytic cell 21 can be recovered.

9. Electrolytic Solution The electrolytic solution is not particularly limited as long as it is a raw material for the first gas and the second gas. For example, the electrolytic solution is an aqueous solution containing an electrolyte, for example, an electrolytic solution containing 0.1 M H ₂ SO ₄ , 0.1M potassium phosphate buffer. In this case, hydrogen and oxygen can be produced from the electrolytic solution as the first gas and the second gas.

Diagram 7 of the gas producing apparatus is a schematic plan view of a gas production apparatus 23 of the present embodiment, FIG. 8 is a schematic sectional view of a gas production device 23 in a dotted line F-F of FIG. 7, FIG. 9 It is a schematic back view of the gas manufacturing apparatus 23 of this embodiment. In FIG. 9, the second substrate is omitted.
10 is a schematic cross-sectional view of the gas production device 23 taken along the alternate long and short dash line GG in FIG. 7, and FIG. 11 is a schematic cross-sectional view of the gas production device 23 taken along the alternate long and short dash line HH in FIG. 10 and 11 are schematic cross-sectional views when the gas production device 23 is installed at an angle so that sunlight efficiently enters the photoelectric conversion unit 2 and the electrolytic solution is put into the electrolytic cell 21. FIG. 12 is a schematic cross-sectional view of the gas production device 23 in a range J surrounded by a dotted line in FIG.
13 to 19 are schematic cross-sectional views of the gas production apparatus 23 of the present embodiment, and correspond to the schematic cross-sectional view of FIG.

The gas production apparatus 23 of the present embodiment includes the electrolytic cell 21 of the present embodiment and the photoelectric conversion unit 2 having a light receiving surface and a back surface thereof, and the first and second electrolysis electrodes 8 and 7 are photoelectric conversion units. 2 is provided in parallel on the back surface of 2 and is provided so as to electrolyze the electrolytic solution using electromotive force generated by the photoelectric conversion unit 2 receiving light to generate a first gas and a second gas, respectively. It is characterized by that.
Moreover, the photoelectric conversion part 2 can be provided on the 1st board | substrate 1 which has translucency.
Hereinafter, the gas production apparatus 23 of the present embodiment will be described.
In addition, since the gas production apparatus 23 of this embodiment contains the electrolytic vessel 21 of this embodiment, the description about the above-mentioned electrolytic vessel 21 is applicable also to the gas production apparatus of this embodiment as long as there is no contradiction.

1. The 1st board | substrate which has translucency The 1st board | substrate 1 which has translucency may be equipped with the gas manufacturing apparatus 23 of this embodiment. The photoelectric conversion unit 2 may be provided on the first substrate 1 so that the light receiving surface is on the first substrate 1 side. In addition, when the photoelectric conversion part 2 consists of semiconductor substrates etc. and has fixed intensity | strength, the 1st board | substrate 1 can be abbreviate | omitted. Moreover, when the photoelectric conversion part 2 can be formed on a flexible material such as a resin film, the first substrate 1 can be omitted.

Moreover, the 1st board | substrate 1 is a member used as the foundation for comprising this gas manufacturing apparatus. Moreover, in order to receive sunlight with the light-receiving surface of the photoelectric conversion unit 2, it is preferable to be transparent and have a high light transmittance. However, as long as the light can be efficiently incident on the photoelectric conversion unit 2. There is no limit to the light transmittance.
As a substrate material having a high light transmittance, for example, a transparent rigid material such as soda glass, quartz glass, Pyrex (registered trademark), or a synthetic quartz plate, or a transparent resin plate or film material is preferably used. In view of chemical and physical stability, it is preferable to use a glass substrate.
A fine uneven structure can be formed on the surface of the first substrate 1 on the photoelectric conversion unit 2 side so that incident light is effectively irregularly reflected on the surface of the photoelectric conversion unit 2. This fine concavo-convex structure can be formed by a known method such as reactive ion etching (RIE) treatment or blast treatment.

2. First Electrode, First Conductive Part The first electrode 4 can be provided on the first substrate 1 and can be provided in contact with the light receiving surface of the photoelectric conversion part 2. Moreover, the 1st electrode 4 may have translucency. Further, the first electrode 4 may be provided directly on the light receiving surface of the photoelectric conversion unit 2 when the first substrate 1 can be omitted. The first electrode 4 can be electrically connected to the second electrolysis electrode 7. By providing the first electrode 4, the current flowing between the light receiving surface of the photoelectric conversion unit 2 and the second electrolysis electrode 7 can be increased. Moreover, when the photoelectric conversion part 2 produces an electromotive force between the 1st area and the 2nd area of the back surface of the photoelectric conversion part 2 like FIG. 18, 19, the 1st electrode 4 is unnecessary.
The first electrode 4 may be electrically connected to the second electrolysis electrode 7 through the first conductive portion 9 as shown in FIGS. 8, 14 and 17, and the second electrolysis electrode 7 as shown in FIG. You may contact with.
The first electrode 4 may be made of a transparent conductive film such as ITO or SnO _2, or may be made of a metal finger electrode such as Ag or Au.

A case where the first electrode 4 is a transparent conductive film will be described below.
The transparent conductive film is used to facilitate contact between the light receiving surface of the photoelectric conversion unit 2 and the second electrolysis electrode 7.
What is generally used as a transparent electrode can be used. Specifically, In—Zn—O (IZO), In—Sn—O (ITO), ZnO—Al, Zn—Sn—O, SnO _{2 and the} like can be given. The transparent conductive film preferably has a sunlight transmittance of 85% or more, particularly 90% or more, and particularly 92% or more. This is because the photoelectric conversion unit 2 can absorb light efficiently.
As a method for producing the transparent conductive film, a known method can be used, and examples thereof include sputtering, vacuum deposition, sol-gel method, cluster beam deposition method, and PLD (Pulse Laser Deposition) method.

The first conductive portion 9 can be provided so as to be in contact with the first electrode 4 and the second electrolysis electrode 7. By providing the first conductive portion 9, the first electrode 4 and the second electrolysis electrode 7 in contact with the light receiving surface of the photoelectric conversion portion 2 can be easily electrically connected.
Moreover, the 1st electroconductive part 9 may be provided in the contact hole which penetrates the photoelectric conversion part 2 like FIG. Thus, the current path between the light receiving surface of the photoelectric conversion unit 2 and the second electrolysis electrode 7 can be shortened, and the first gas and the second gas can be generated more efficiently. Moreover, the contact hole provided with the 1st electroconductive part 9 may have one or more, and may have a circular cross section.
Moreover, the 1st electroconductive part 9 may be provided so that the side surface of the photoelectric conversion part 2 may be covered like FIG.

  The material of the 1st electroconductive part 9 will not be restrict | limited especially if it has electroconductivity. A paste containing conductive particles, for example, a carbon paste, an Ag paste or the like applied by screen printing, an inkjet method, etc., dried or baked, a method of forming a film by a CVD method using a raw material gas, a PVD method, Examples thereof include a vapor deposition method, a sputtering method, a sol-gel method, and a method using an electrochemical redox reaction.

3. Photoelectric Conversion Unit The photoelectric conversion unit 2 has a light receiving surface and a back surface thereof, and a first electrolysis electrode 8 and a second electrolysis electrode 7 are provided on the back surface of the photoelectric conversion unit 2. The light receiving surface is a surface that receives light for photoelectric conversion, and the back surface is the back surface of the light receiving surface. The photoelectric conversion unit 2 can be provided on the first substrate 1 on which the first electrode 4 is provided with the light receiving surface facing down. For example, an electromotive force may be generated between the light receiving surface and the back surface of the photoelectric conversion unit 2 as illustrated in FIGS. 8 and 13 to 17. An electromotive force may be generated between the first area and the second area. 18 and 19 can be formed by a semiconductor substrate on which an n-type semiconductor region 37 and a p-type semiconductor region 36 are formed.
Although the shape of the photoelectric conversion part 2 is not specifically limited, For example, it can be set as a square shape.
The photoelectric conversion unit 2 is not particularly limited as long as it can separate charges by incident light and generates an electromotive force. For example, the photoelectric conversion unit using a silicon-based semiconductor or the photoelectric conversion unit using a compound semiconductor A photoelectric conversion part using a dye sensitizer, a photoelectric conversion part using an organic thin film, and the like.

  When either one of the first gas and the second gas is hydrogen and the other is oxygen, the photoelectric conversion unit 2 receives light in the first electrolysis electrode 8 and the second electrolysis electrode 7. It is necessary to use a material that generates an electromotive force necessary for generating hydrogen and oxygen. The potential difference between the first electrolysis electrode 8 and the second electrolysis electrode 7 needs to be larger than the theoretical voltage (1.23 V) for water decomposition, and for this purpose, a sufficiently large potential difference needs to be generated in the photoelectric conversion unit 2. There is. Therefore, it is preferable that the photoelectric conversion unit 2 connects two or more junctions in series such as a pn junction to generate an electromotive force. For example, it can have a structure in which the photoelectric conversion layers provided side by side as shown in FIGS.

  Examples of the material that performs photoelectric conversion include silicon-based semiconductors, compound semiconductors, and materials based on organic materials, and any photoelectric conversion material can be used. In order to increase the electromotive force, these photoelectric conversion materials can be stacked. In the case of stacking, it is possible to form a multi-junction structure with the same material, but stacking multiple photoelectric conversion layers with different optical band gaps and complementing the low sensitivity wavelength region of each photoelectric conversion layer mutually By doing so, incident light can be efficiently absorbed over a wide wavelength region. The plurality of photoelectric conversion layers preferably have different band gaps. According to such a configuration, the electromotive force generated in the photoelectric conversion unit 2 can be increased, and the electrolytic solution can be electrolyzed more efficiently.

Moreover, it is possible to interpose a conductor such as a transparent conductive film between the layers in order to improve the serial connection characteristics between the photoelectric conversion layers and to match the photocurrent generated in the photoelectric conversion unit 2. Thereby, it becomes possible to suppress deterioration of the photoelectric conversion unit 2.
An example of the photoelectric conversion unit 2 will be specifically described below. The photoelectric conversion unit 2 may be a combination of these. Moreover, as long as there is no contradiction, the example of the following photoelectric conversion parts 2 can also be made into a photoelectric converting layer.

3-1. Photoelectric conversion part using a silicon-based semiconductor Examples of the photoelectric conversion part 2 using a silicon-based semiconductor include a single crystal type, a polycrystalline type, an amorphous type, a spherical silicon type, and combinations thereof. Any of them can have a pn junction in which a p-type semiconductor and an n-type semiconductor are joined. Further, a pin junction in which an i-type semiconductor is provided between a p-type semiconductor and an n-type semiconductor may be provided. Further, it may have a plurality of pn junctions, a plurality of pin junctions, or a pn junction and a pin junction.
The silicon-based semiconductor is a semiconductor containing silicon, such as silicon, silicon carbide, or silicon germanium. In addition, silicon or the like in which n-type impurities or p-type impurities are added is included, and crystalline, amorphous, or microcrystalline silicon is also included.
In addition, the photoelectric conversion unit 2 using a silicon-based semiconductor may be a thin film or thick photoelectric conversion layer formed on the first substrate 1, and a pn junction or a pin is attached to a wafer such as a silicon wafer. A junction may be formed, or a thin film photoelectric conversion layer may be formed on a wafer on which a pn junction or a pin junction is formed.

An example of forming the photoelectric conversion unit 2 using a silicon-based semiconductor is shown below.
A first conductivity type semiconductor layer is formed on the first electrode 4 stacked on the first substrate 1 by a method such as a plasma CVD method. As the first conductive type semiconductor layer, a p ⁺ type or n ⁺ type amorphous Si thin film doped with a conductivity type determining impurity atom concentration of about 1 × 10 ^{18 to} 5 × 10 ²¹ / cm ³ , or many A crystalline or microcrystalline Si thin film is used. The material of the first conductivity type semiconductor layer is not limited to Si, and it is also possible to use a compound such as SiC, SiGe, or Si _x O _1-x .

On the first conductivity type semiconductor layer thus formed, a polycrystalline or microcrystalline crystalline Si thin film is formed as a crystalline Si photoactive layer by a method such as plasma CVD. The conductivity type is the first conductivity type having a lower doping concentration than the first conductivity type semiconductor, or the i conductivity type. The material for the crystalline Si-based photoactive layer is not limited to Si, and it is also possible to use a compound such as SiC, SiGe, or Si _x O _1-x .

Next, in order to form a semiconductor junction on the crystalline Si-based photoactive layer, a second conductivity type semiconductor layer having a conductivity type opposite to the first conductivity type semiconductor layer is formed by a method such as plasma CVD. As the second conductive type semiconductor layer, an n ⁺ type or p ⁺ type amorphous Si thin film doped with about 1 × 10 ^{18 to} 5 × 10 ²¹ / cm ³ of a conductivity type determining impurity atom, or polycrystalline Alternatively, a microcrystalline Si thin film is used. The material of the second conductivity type semiconductor layer is not limited to Si, and it is also possible to use a compound such as SiC, SiGe, or Si _x O _1-x . In order to further improve the bonding characteristics, it is possible to insert a substantially i-type non-single-crystal Si-based thin film between the crystalline Si-based photoactive layer and the second conductive type semiconductor layer. In this manner, one photoelectric conversion layer closest to the light receiving surface can be stacked.

  Subsequently, a second photoelectric conversion layer is formed. The second photoelectric conversion layer is composed of a first conductivity type semiconductor layer, a crystalline Si-based photoactive layer, and a second conductivity type semiconductor layer, each layer corresponding to the first photoelectric conversion layer. The first conductive type semiconductor layer, the crystalline Si-based photoactive layer, and the second conductive type semiconductor layer are formed. When a potential sufficient for water splitting cannot be obtained with a two-layer tandem, it is preferable to take a three-layer structure or more. However, the volume crystallization fraction of the crystalline Si photoactive layer of the second photoelectric conversion layer is preferably higher than that of the first crystalline Si photoactive layer. Similarly, when three or more layers are laminated, it is preferable to increase the volume crystallization fraction as compared with the lower layer. This increases the absorption in the long wavelength region, shifts the spectral sensitivity to the long wavelength side, and can improve the sensitivity in a wide wavelength region even when the photoactive layer is configured using the same Si material. It is because it becomes. That is, by using a tandem structure with Si having different crystallization rates, the spectral sensitivity is widened, and light can be used with high efficiency. At this time, if the low crystallization rate material is not on the light receiving surface side, high efficiency cannot be achieved. Further, when the crystallization rate is lowered to 40% or less, the amorphous component increases and deterioration occurs.

Next, the example of formation of the photoelectric conversion part 2 using a silicon substrate is shown below.
As the silicon substrate, a single crystal silicon substrate, a polycrystalline silicon substrate, or the like can be used, and may be p-type, n-type, or i-type. An n-type semiconductor portion 37 is formed by doping an n-type impurity such as P into a part of the silicon substrate by thermal diffusion or ion implantation, and a p-type impurity such as B is heated on the other part of the silicon substrate. The p-type semiconductor portion 36 can be formed by doping by diffusion or ion implantation. Thus, pn junction in the silicon substrate, pin junction can be formed and npp ⁺ junction or pnn ⁺ junction, it is possible to form a photoelectric conversion unit 2.

Each of the n-type semiconductor portion 37 and the p-type semiconductor portion 36 can form one region on the silicon substrate as shown in FIGS. 18 and 19, and one of the n-type semiconductor region 37 and the p-type semiconductor region 36 is formed. A plurality of can be formed. In addition, as shown in FIG. 19, the photoelectric conversion unit 2 can be formed by arranging the silicon substrates on which the n-type semiconductor region 37 and the p-type semiconductor region 36 are arranged side by side and connecting them in series by the fourth conductive unit 33.
Note that, although described with reference to a silicon substrate, pn junction, pin junction, may use other semiconductor substrate or the like can be formed npp ⁺ junction or pnn ⁺ junction. In addition, as long as the n-type semiconductor portion 37 and the p-type semiconductor portion 36 can be formed, the semiconductor layer is not limited to the semiconductor substrate, and may be a semiconductor layer formed on the substrate.

3-2. Photoelectric conversion part using compound semiconductor The photoelectric conversion part using a compound semiconductor is, for example, GaP, GaAs, InP, InAs, or IId-VI group elements composed of III-V group elements, CdTe / CdS, Examples thereof include those in which a pn junction is formed using CIGS (Copper Indium Gallium DiSelenide) composed of a group I-III-VI.

An example of a method for manufacturing a photoelectric conversion unit using a compound semiconductor is shown below. In this manufacturing method, all film-forming processes are continuously performed using a metal organic chemical vapor deposition (MOCVD) apparatus. Done. As a group III element material, for example, an organic metal such as trimethylgallium, trimethylaluminum, or trimethylindium is supplied to the growth apparatus using hydrogen as a carrier gas. For example, a gas such as arsine (AsH ₃ ), phosphine (PH ₃ ), and stibine (SbH ₃ ) is used as the material of the group V element. As a dopant of p-type impurities or n-type impurities, for example, diethyl zinc for p-type conversion, monosilane (SiH ₄ ), disilane (Si ₂ H ₆ ), hydrogen selenide (H ₂ Se) for n-type conversion. Etc. are used. These source gases can be thermally decomposed by supplying them onto a substrate heated to, for example, 700 ° C., and a desired compound semiconductor material film can be epitaxially grown. The composition of these growth layers can be controlled by the gas composition to be introduced, and the film thickness can be controlled by the gas introduction time. When multi-junction laminating these photoelectric conversion parts, it is possible to form a growth layer with excellent crystallinity by adjusting the lattice constant between layers as much as possible, and to improve the photoelectric conversion efficiency. Become.

  In addition to the portion where the pn junction is formed, for example, a known window layer on the light receiving surface side or a known electric field layer on the non-light receiving surface side may be provided to improve carrier collection efficiency. Further, a buffer layer for preventing diffusion of impurities may be provided.

3-3. Photoelectric conversion part using a dye sensitizer The photoelectric conversion part using a dye sensitizer is mainly composed of, for example, a porous semiconductor, a dye sensitizer, an electrolyte, a solvent, and the like.
As a material constituting the porous semiconductor, for example, one or more kinds of known semiconductors such as titanium oxide, tungsten oxide, zinc oxide, barium titanate, strontium titanate, cadmium sulfide can be selected. As a method for forming a porous semiconductor on a substrate, a paste containing semiconductor particles is applied by a screen printing method, an ink jet method and the like, dried or baked, a method of forming a film by a CVD method using a raw material gas, etc. , PVD method, vapor deposition method, sputtering method, sol-gel method, method using electrochemical oxidation-reduction reaction, and the like.

  As the dye sensitizer adsorbed on the porous semiconductor, various dyes having absorption in the visible light region and the infrared light region can be used. Here, in order to firmly adsorb the dye to the porous semiconductor, the carboxylic acid group, carboxylic anhydride group, alkoxy group, sulfonic acid group, hydroxyl group, hydroxylalkyl group, ester group, mercapto group, phosphonyl in the dye molecule It is preferable that a group or the like is present. These functional groups provide an electrical bond that facilitates electron transfer between the excited state dye and the conduction band of the porous semiconductor.

  Examples of dyes containing these functional groups include ruthenium bipyridine dyes, quinone dyes, quinone imine dyes, azo dyes, quinacridone dyes, squarylium dyes, cyanine dyes, merocyanine dyes, and triphenylmethane dyes. Xanthene dyes, porphyrin dyes, phthalocyanine dyes, berylene dyes, indigo dyes, naphthalocyanine dyes, and the like.

  Examples of the method for adsorbing the dye to the porous semiconductor include a method in which the porous semiconductor is immersed in a solution in which the dye is dissolved (dye adsorption solution). The solvent used in the dye adsorption solution is not particularly limited as long as it dissolves the dye, and specifically, alcohols such as ethanol and methanol, ketones such as acetone, ethers such as diethyl ether and tetrahydrofuran. Nitrogen compounds such as acetonitrile, aliphatic hydrocarbons such as hexane, aromatic hydrocarbons such as benzene, esters such as ethyl acetate, water, and the like.

The electrolyte is composed of a redox pair and a solid medium such as a liquid or polymer gel holding the redox pair.
In general, iron- and cobalt-based metals and halogen substances such as chlorine, bromine, and iodine are preferably used as the redox pair, and metal iodides such as lithium iodide, sodium iodide, and potassium iodide and iodine are used. The combination of is preferably used. Furthermore, imidazole salts such as dimethylpropylimidazole iodide can also be mixed.

  Examples of the solvent include carbonate compounds such as propylene carbonate, nitrile compounds such as acetonitrile, alcohols such as ethanol and methanol, water, aprotic polar substances, and the like. Of these, carbonate compounds and nitrile compounds are preferred. Used.

3-4. Photoelectric conversion part using organic thin film Photoelectric conversion part 2 using an organic thin film is an electron hole transport layer composed of an organic semiconductor material having electron donating properties and electron accepting properties, or an electron transport layer having electron accepting properties. And a hole transport layer having an electron donating property may be laminated.
The electron-donating organic semiconductor material is not particularly limited as long as it has a function as an electron donor, but it is preferable that a film can be formed by a coating method, and among them, an electron-donating conductive polymer is preferably used. The

  Here, the conductive polymer means a π-conjugated polymer, which is composed of a π-conjugated system in which double bonds or triple bonds containing carbon-carbon or hetero atoms are alternately linked to single bonds, and exhibits semiconducting properties. Point.

  Examples of the electron-donating conductive polymer material include polyphenylene, polyphenylene vinylene, polythiophene, polycarbazole, polyvinyl carbazole, polysilane, polyacetylene, polypyrrole, polyaniline, polyfluorene, polyvinyl pyrene, polyvinyl anthracene, and derivatives, Examples thereof include a polymer, a phthalocyanine-containing polymer, a carbazole-containing polymer, and an organometallic polymer. Among these, thiophene-fluorene copolymer, polyalkylthiophene, phenyleneethynylene-phenylene vinylene copolymer, fluorene-phenylene vinylene copolymer, thiophene-phenylene vinylene copolymer, and the like are preferably used.

The electron-accepting organic semiconductor material is not particularly limited as long as it has a function as an electron acceptor. However, it is preferable that a film can be formed by a coating method, and among them, an electron-donating conductive polymer is preferably used. The
Examples of the electron-accepting conductive polymer include polyphenylene vinylene, polyfluorene, and derivatives and copolymers thereof, or carbon nanotubes, fullerene and derivatives thereof, CN group or CF ₃ group-containing polymers, and -CF thereof. Examples thereof include _3- substituted polymers.

In addition, an electron-accepting organic semiconductor material doped with an electron-donating compound, an electron-donating organic semiconductor material doped with an electron-accepting compound, or the like can be used. Examples of the electron-accepting conductive polymer material doped with the electron-donating compound include the above-described electron-accepting conductive polymer material. As the electron-donating compound to be doped, for example, a Lewis base such as an alkali metal such as Li, K, Ca, or Cs or an alkaline earth metal can be used. The Lewis base acts as an electron donor. Examples of the electron-donating conductive polymer material doped with the electron-accepting compound include the above-described electron-donating conductive polymer material. As the electron-accepting compound to be doped, for example, a Lewis acid such as FeCl ₃ , AlCl ₃ , AlBr ₃ , AsF ₆ or a halogen compound can be used. In addition, Lewis acid acts as an electron acceptor.

  In the photoelectric conversion unit 2 shown above, it is assumed that sunlight is received and photoelectric conversion is primarily performed. However, it is emitted from a fluorescent lamp, an incandescent lamp, an LED, or a specific heat source depending on the application. It is also possible to perform photoelectric conversion by irradiating artificial light such as light.

4). Second Electrode The second electrode 5 can be provided between the back surface of the photoelectric conversion unit 2 and the first electrolysis electrode 8 and between the back surface of the photoelectric conversion unit 2 and the insulating unit 11. The second electrode 5 can be electrically connected to the first electrolysis electrode 8. By providing the second electrode 5, it is possible to reduce ohmic cross between the back surface of the photoelectric conversion unit 2 and the first electrolysis electrode 8. The second electrode 5 may be in contact with the first electrolysis electrode 8. Moreover, it is preferable that the 2nd electrode 5 has the corrosion resistance with respect to electrolyte solution, and the liquid shielding property with respect to electrolyte solution. Thereby, corrosion of the photoelectric conversion part 2 by electrolyte solution can be prevented.
Although it will not specifically limit if the 2nd electrode 5 has electroconductivity, For example, it is a metal thin film, for example, is thin films, such as Al, Ag, Au. These can be formed by, for example, sputtering. Further, for example, a transparent conductive film such as In—Zn—O (IZO), In—Sn—O (ITO), ZnO—Al, Zn—Sn—O, and SnO ₂ is used.

5. Insulating part The insulating part 11 can be provided in order to prevent the occurrence of leakage current. For example, as shown in FIGS. 8 and 14, when the first conductive portion 9 is provided in a contact hole that penetrates the photoelectric conversion portion 2, the insulating portion 11 can be provided on the side wall of the contact hole.
Moreover, the insulating part 11 can be provided between the electrode 7 for 2nd electrolysis and the back surface of the photoelectric conversion part 2 like FIG. This can prevent a leak current from being generated between the second electrolysis electrode 7 and the back surface of the photoelectric conversion unit 2. When the photoelectric conversion unit 2 receives light as shown in FIGS. 18 and 19 to generate a potential difference between the first area and the second area on the back surface of the photoelectric conversion unit 2, the insulating unit 11 1 between the electrode 8 for electrolysis and the back surface of the photoelectric conversion unit 2, and between the second electrode for electrolysis 7 and the back surface of the photoelectric conversion unit 2, and the insulating unit 11 is provided on the first area and the second area. You may have an opening on it. Thereby, the electrons and holes formed by the photoelectric conversion unit 2 receiving light can be efficiently separated, and the photoelectric conversion efficiency can be further increased.
Moreover, it is preferable that the insulation part 11 has the corrosion resistance with respect to electrolyte solution, and the liquid shielding property with respect to electrolyte solution. Thereby, generation | occurrence | production of a leakage current can be prevented and corrosion of the photoelectric conversion part 2 by electrolyte solution can be prevented.

The insulating part 11 can be used regardless of an organic material or an inorganic material. For example, polyamide, polyimide, polyarylene, aromatic vinyl compound, fluorine polymer, acrylic polymer, vinylamide polymer, etc. Examples of organic polymers and inorganic materials include metal oxides such as Al ₂ O ₃ , SiO ₂ such as porous silica films, fluorine-added silicon oxide films (FSG), SiOC, HSQ (Hydrogen Silsesquioxane) films, SiN _x , It is possible to use a method of forming a film by dissolving silanol (Si (OH) ₄ ) in a solvent such as alcohol and applying and heating.

  As a method for forming the insulating portion 11, a film containing a paste containing an insulating material is applied by a screen printing method, an ink jet method, a spin coating method, etc., dried or baked, or a CVD method using a source gas is used. And a method using a PVD method, a vapor deposition method, a sputtering method, a sol-gel method, and the like.

6). The second conductive portion and the third conductive portion The second conductive portion 24 can be provided between the insulating portion 11 and the second electrolysis electrode 7, and the third conductive portion 25 is the insulating portion 11 and the first electrolysis portion It can be provided between the electrodes 8. By providing the second conductive portion 24 or the third conductive portion 25, the electromotive force generated by the photoelectric conversion portion 2 receiving light can be efficiently output to the first electrolysis electrode 8 and the second electrolysis electrode 7. It is possible to reduce ohmic cross. The second conductive part 24 and the third conductive part 25 can be provided as shown in FIGS.
The second conductive portion 24 or the third conductive portion 25 preferably has corrosion resistance to the electrolytic solution and liquid shielding properties to the electrolytic solution. Thereby, an increase in ohmic resistance can be prevented, and corrosion of the photoelectric conversion unit 2 due to the electrolytic solution can be prevented.
The second conductive portion 24 or the third conductive portion 25 is not particularly limited as long as it has conductivity. For example, the second conductive portion 24 or the third conductive portion 25 is a metal thin film, and is a thin film such as Al, Ag, or Au. These can be formed by, for example, sputtering. Further, for example, a transparent conductive film such as In—Zn—O (IZO), In—Sn—O (ITO), ZnO—Al, Zn—Sn—O, and SnO ₂ is used.

7). The first electrolysis electrode, the second electrolysis electrode, the side wall portion The first electrolysis electrode 8 and the second electrolysis electrode 7 are applicable as long as the above description of the electrolysis electrode of the electrolytic cell 21 is not contradictory, but the gas production apparatus 23, the first electrolysis electrode 8 and the second electrolysis electrode 7 are provided in parallel on the back surface of the photoelectric conversion unit 2. In addition, the first and second electrolysis electrodes 8 and 7 electrolyze the electrolytic solution using an electromotive force generated when the photoelectric conversion unit 2 receives light, so that a first gas and a second gas are generated, respectively. Is provided.
For example, when an electromotive force is generated between the light receiving surface and the back surface thereof when the photoelectric conversion unit 2 receives light, the first electrolysis electrode 8 is connected to the back surface of the photoelectric conversion unit 2 as illustrated in FIGS. The second electrolysis electrode 7 can be electrically connected to the light receiving surface of the photoelectric conversion unit 2. Further, when an electromotive force is generated between the first area and the second area on the back surface of the photoelectric conversion unit 2 by receiving light, the first electrolysis electrode 8 is connected to the first area and the second area as shown in FIGS. The second electrolysis electrode 7 can be electrically connected to the other of the first area and the second area.

The first electrolysis electrode 8 can be electrically connected to the back surface of the photoelectric conversion unit 2 through the switching unit 29, and the second electrolysis electrode 7 can be connected to the photoelectric conversion unit 2 through the switching unit 29. It can be electrically connected to the light receiving surface. For example, when the gas production apparatus 23 has a cross section as shown in FIG. 13, the second electrolysis electrode 7 can be electrically connected to the light receiving surface of the photoelectric conversion unit 2 via the switching unit 29. 14 has a cross section as shown in FIG. 14, the first electrolysis electrode 8 can be electrically connected to the back surface of the photoelectric conversion unit 2 via the switching unit 29, and the gas production device 23 is as shown in FIG. 15. In the case of having a simple cross section, the second electrolysis electrode 7 can be electrically connected to the light receiving surface of the photoelectric conversion unit 2 via the switching unit 29, and the first electrolysis electrode 8 can be electrically connected via the switching unit 29. It can be electrically connected to the back surface of the converter 2.
Moreover, it is preferable that at least one of the first electrolysis electrode 8 and the second electrolysis electrode 7 has a catalyst surface area larger than the area of the light receiving surface of the photoelectric conversion unit 2. According to such a configuration, the first gas or the second gas can be generated more efficiently by the electromotive force generated in the photoelectric conversion unit 2.

In the gas generator 23, the photoelectric conversion unit 2 and the first or second electrolysis electrodes 8 and 7 constitute the side wall of the electrolytic cell 21. When the photoelectric conversion unit 2 is provided on the first substrate 1, the first substrate 1 also constitutes a side wall.
For example, when the gas production apparatus 23 has a cross section as shown in FIGS. 10 and 11, the first substrate 1, the photoelectric conversion unit 2, the first or second electrolysis electrodes 8, 7, etc. are one side wall of the electrolytic cell 21. Thus, the second substrate 14 becomes one side wall of the electrolytic cell 21. In FIG. 10, the second electrolysis electrode 7 constitutes the first inner surface 42 of the electrolytic cell 21, and the portion of the second substrate 14 facing the first inner surface becomes the side wall portion 17, and the second inner surface 43. Configure. In FIG. 11, the first electrolysis electrode 8 constitutes the first inner side surface 42 of the electrolytic cell 21, and the portion of the second substrate 14 facing the first inner side surface becomes the side wall portion 17, and the second inner side surface 43 is configured. About the side wall part 17 of the gas manufacturing apparatus 23, unless the description about the side wall part 17 of the above-mentioned electrolytic vessel 21 is inconsistent, the side wall part 17 has the 1st level | step-difference part 45. FIG. Further, the side wall portion 17 can have a second stepped portion 46.

Here, the gas production apparatus 23 is inclined and installed so that sunlight efficiently enters the photoelectric conversion unit 2, the electrolytic solution is filled in the electrolytic cell 21, and the surfaces of the first and second electrolysis electrodes 8 and 7. A case where bubbles are generated from the above will be described.
FIG. 12 is a schematic cross-sectional view of the gas production device 23 in a range J surrounded by a dotted line in FIG. 10, and is a schematic view when bubbles are generated from the first inner side surface 42 of the second electrolysis electrode 7. When sunlight is incident on the photoelectric conversion unit 2 and a voltage is applied between the first electrolysis electrode 8 and the second electrolysis electrode 7 by the photovoltaic power of the photoelectric conversion unit 2, electrolysis in the electrolytic cell 21 is performed. When the liquid is electrolyzed, a first gas is generated as bubbles 12 on the first inner surface 42 of the first electrolysis electrode 8, and a second gas is generated on the first inner surface 42 of the second electrolysis electrode 7. Occurs as. The bubbles 12 generated on the first inner side surface 42 float in the electrolyte along the first inner side surface 42 by the buoyancy, and the bubbles that rise to the vicinity of the liquid level 41 of the electrolyte solution Release into the gas phase. The released gas is discharged from the first gas discharge port 20 or the second gas discharge port 19 and can collect the first gas or the second gas. At this time, the gas in the bubble 12 having a relatively large diameter is easily released from the liquid surface of the electrolytic solution into the gas phase, but the gas in the bubble 12 having a relatively small diameter is easily discharged from the electrolyte solution. Bubbles may drift in the electrolyte without being released from the surface into the gas phase.

When the bubbles 12 are generated from the first inner side surface 42, it is considered that the upward flow of the electrolyte flowing along the first inner side surface 42 is generated by the bubbles 12 floating along the first inner side surface 42. Further, it is considered that this upward flow is also generated when the electrode for electrolysis generates heat. Further, such an upward flow may be generated by a stirrer or the like in order to efficiently collect bubbles on the surface of the electrode for electrolysis.
The upward flow of the electrolytic solution is a flow toward the first surface 47 of the side wall portion 17 along the seal member 16 in the vicinity of the liquid surface 41 of the electrolytic solution, and further in the vicinity of the first surface 47 and the first step portion 45. It is considered that the air then flows toward the bottom of the electrolytic cell 21 and then convects in the electrolytic cell 21.

Among the bubbles 12 generated from the first inner side surface 42 and floating near the liquid surface of the electrolytic solution, the bubbles having a relatively small diameter and in which the internal gas is not released into the gas phase ride on the flow of the electrolytic solution. It is considered that the gas flows in the electrolytic cell 21. However, when the electrolytic solution flows in the vicinity of the first stepped portion 45, the electrolytic solution flows from the first surface 47 side of the second inner side surface 43 toward the first inner side surface 42 side. It is thought that it floats by the buoyancy. Therefore, by providing the first step 45, the bubbles 12 can be lifted again without the bubbles 12 getting on the electrolyte flow toward the bottom of the electrolytic cell 21. It is considered that the bubbles 12 float near the liquid surface of the electrolytic solution and again ride on the flow of the electrolytic solution from the first inner side surface 42 side toward the second inner side surface 43 side.
Therefore, by providing the first step portion 45, the bubbles 12 can be convected in the electrolytic solution between the liquid surface 41 and the first step portion 45. Thereby, a plurality of bubbles can be combined in the electrolyte solution between the liquid surface 41 and the first step portion 45 to form a bubble having a relatively large diameter. The bubbles having a relatively large diameter can easily release the gas therein into the gas phase, and the released gas is discharged from the first gas discharge port 20 or the second gas discharge port 19 and the first gas. Alternatively, the second gas can be recovered.

8). Switching unit The switching unit 29 includes a circuit that outputs an electromotive force generated when the photoelectric conversion unit 2 receives light to the first external circuit, and an electromotive force generated when the photoelectric conversion unit 2 receives light. It is possible to switch between circuits that output to the second electrolysis electrode 7 and generate the first gas and the second gas from the electrolyte, respectively. As a result, the electromotive force generated when the photoelectric conversion unit 2 receives light can be supplied as power to the first external circuit, and the first gas and the second gas are generated using the electromotive force generated when the photoelectric conversion unit 2 receives light. A gas can be produced.
A method for electrically connecting the switching unit 29 to the first external circuit is not particularly limited. For example, the switching unit 29 includes an output terminal and is electrically connected to the first external circuit via the output terminal. Good.

The switching unit 29 can be electrically connected to the second external circuit, and outputs an electromotive force input from the second external circuit to the first electrolysis electrode 8 and the second electrolysis electrode 7. It can switch to the circuit which produces | generates 1st gas and 2nd gas, respectively from electrolyte solution. Thus, the first gas and the second gas can be produced from the electrolyte using the electromotive force input from the second external circuit.
The method for electrically connecting the switching unit 29 to the second external circuit is not particularly limited. For example, the switching unit 29 may include an input terminal and be electrically connected to the second external circuit via the input terminal. .

Gas Manufacturing Method In the gas manufacturing method of the present embodiment, the gas manufacturing apparatus 23 is installed so that the light receiving surface of the photoelectric conversion unit 2 is inclined with respect to the horizontal plane, the electrolytic solution is introduced into the electrolytic solution chamber 15, and sunlight is photoelectrically generated. The first gas and the second gas are generated from the first electrolysis electrode 8 and the second electrolysis electrode 7 by being incident on the light receiving surface of the conversion unit 2, and the first gas discharge port 20 and the second gas discharge port 19. The first gas and the second gas can be discharged respectively from
Thereby, the first gas and the second gas can be produced.

    1: 1st board | substrate 2: Photoelectric conversion part 4: 1st electrode 5: 2nd electrode 7: Electrode for 2nd electrolysis 8: Electrode for 1st electrolysis 9: 1st electroconductive part 10: Terminal part 11: Insulation part 12: Bubble 13: Partition 14: Second substrate 15: Electrolyte chamber 16: Sealing material 17: Side wall 18: Water supply port 19: Second gas discharge port 20: First gas discharge port 21: Electrolytic tank 22: Electrolyte solution 23: Gas production device 24: second conductive part 25: third conductive part 28: photoelectric conversion layer 29: switching part 30: translucent electrode 31: back electrode 33: fourth conductive part 35: semiconductor part 36: p-type semiconductor part 37: n-type semiconductor portion 40: isolation 41: liquid level 42: first inner side surface 43: second inner side surface 45: first stepped portion 46: second stepped portion 47: first surface 48: first 2nd surface 49: 3rd surface 50: Hydrophilic member 51: Step member 52: Wiring 101: Substrate 107: Electrode for electrolysis 114: Second substrate 116: Sealing material 119: Gas discharge port

Claims (33)

An electrolytic cell having at least one electrode for electrolysis and a side wall,
The electrode for electrolysis constitutes a first inner surface of the electrolytic cell,
The side wall portion constitutes a second inner surface of the electrolytic cell facing the first inner surface,
The side wall portion has a first step portion such that an interval between the first inner side surface and the second inner side surface is wider than the bottom side at the upper part of the electrolytic cell,
When the first step portion contains the electrolytic solution in the electrolytic cell and is electrolyzed to generate bubbles from the first inner surface, the buoyancy of the bubbles causes an electrolyte solution between the liquid surface and the first step portion. An electrolytic cell characterized in that bubbles are provided to convect.   The first step portion suppresses the bubbles in the vicinity of the electrolyte surface from flowing into the electrolytic cell deeper than the first step portion when the electrolyte is electrolyzed to generate bubbles from the first inner surface. The electrolytic cell according to claim 1, which is provided on the surface.   The electrolytic cell according to claim 1, wherein the first step portion includes a plurality of steps. The second inner surface is provided on the first surface and on the bottom side of the electrolytic cell of the first surface, and the distance between the first inner surface and the first surface is larger than the distance between the first surface and the first inner surface. A second narrow surface,
The electrolytic cell according to any one of claims 1 to 3, wherein the first step portion is provided between the first surface and the second surface.   The electrolytic cell according to claim 4, wherein the first surface has hydrophilicity. The side wall portion has a second step portion on the bottom side of the electrolytic cell of the first step portion,
The second inner surface is provided on the bottom surface of the electrolytic cell on the second surface, and a third surface having a larger distance between the first inner surface than the distance between the second surface and the first inner surface. Have
The electrolytic cell according to claim 4 or 5, wherein the second step portion is provided between the second surface and the third surface. The electrolytic cell includes a first electrolysis electrode and a second electrolysis electrode as the electrolysis electrode,
The electrolytic cell according to any one of claims 1 to 6, wherein the first and second electrodes for electrolysis are provided so as to electrolyze the electrolytic solution to generate a first gas and a second gas, respectively. The first and second electrolysis electrodes are provided in parallel,
The electrolytic cell according to claim 7, further comprising a partition wall provided between the first electrolysis electrode and the second electrolysis electrode.   The electrolytic cell according to claim 8, wherein the partition wall includes an ion exchanger.   The electrolytic cell according to any one of claims 7 to 9, wherein one of the first gas and the second gas is hydrogen and the other is oxygen. The electrolytic cell according to any one of claims 7 to 10, and a photoelectric conversion unit having a light receiving surface and a back surface thereof,
The first and second electrodes for electrolysis are provided in parallel on the back surface, and electrolyze the electrolytic solution using electromotive force generated by the photoelectric conversion unit receiving light, respectively, and the first gas and the second electrode, respectively. 2 A gas production apparatus provided to generate gas. The photoelectric conversion unit generates an electromotive force between the light receiving surface and the back surface by receiving light,
The first electrolysis electrode is provided so as to be electrically connected to the back surface of the photoelectric conversion unit,
The device according to claim 11, wherein the second electrolysis electrode is provided so as to be electrically connected to a light receiving surface of the photoelectric conversion unit.   The apparatus according to claim 12, further comprising an insulating part provided between a second electrolysis electrode and a back surface of the photoelectric conversion part.   The apparatus according to claim 12, further comprising a first electrode that contacts a light receiving surface of the photoelectric conversion unit.   The apparatus according to claim 14, further comprising a first conductive portion that electrically connects the first electrode and the second electrolysis electrode.   The device according to claim 15, wherein the first conductive part is provided in a contact hole penetrating the photoelectric conversion part. The insulating part is provided so as to cover a side surface of the photoelectric conversion part,
The device according to claim 15, wherein the first conductive portion is provided on a portion that is a part of the insulating portion and covers a side surface of the photoelectric conversion portion. The insulating part is provided so as to cover a side surface of the photoelectric conversion part,
The device according to claim 14, wherein the second electrolysis electrode is provided on a portion that is a part of the insulating portion and covers a side surface of the photoelectric conversion portion, and is in contact with the first electrode.   The device according to claim 11, wherein the photoelectric conversion unit includes a photoelectric conversion layer including a p-type semiconductor layer, an i-type semiconductor layer, and an n-type semiconductor layer. The photoelectric conversion unit generates a potential difference between the first and second areas on the back surface of the photoelectric conversion unit by receiving light,
The apparatus according to claim 11, wherein the first area is provided to be electrically connected to the first electrolysis electrode, and the second area is provided to be electrically connected to the second electrolysis electrode.   21. The apparatus according to claim 20, further comprising an insulating part provided between the first and second electrolysis electrodes and the back surface of the photoelectric conversion part and having openings on the first area and the second area.   The first area is provided so as to be electrically connected to the first electrolysis electrode via the third conductive part, and the second area is electrically connected to the second electrolysis electrode via the second conductive part. 24. The apparatus of claim 21, wherein the apparatus is arranged to do so. The photoelectric conversion part is made of at least one semiconductor material having an n-type semiconductor part and a p-type semiconductor part,
23. The apparatus according to claim 20, wherein one of the first and second areas is a part of the n-type semiconductor part, and the other is a part of the p-type semiconductor part. A first substrate having translucency;
The said photoelectric conversion part is an apparatus as described in any one of Claims 11-23 provided on the 1st board | substrate. The photoelectric conversion unit includes a plurality of photoelectric conversion layers connected in series,
The device according to any one of claims 11 to 24, wherein the plurality of photoelectric conversion layers are provided so as to supply an electromotive force generated by receiving light to the first electrolysis electrode and the second electrolysis electrode.   26. The apparatus according to claim 25, wherein each photoelectric conversion layer is connected in series by a fourth conductive portion.   27. The device according to claim 26, wherein the fourth conductive portion includes a translucent electrode provided on a light receiving surface side of the photoelectric conversion layer and a back electrode provided on a back surface side of the photoelectric conversion layer. Of the first electrolysis electrode and the second electrolysis electrode, one is a hydrogen generation unit that generates H ₂ from the electrolytic solution, and the other is an oxygen generation unit that generates O ₂ from the electrolytic solution,
The hydrogen generation part and the oxygen generation part each include a hydrogen generation catalyst that is a catalyst for a reaction that generates H ₂ from an electrolytic solution and an oxygen generation catalyst that is a catalyst for a reaction that generates O ₂ from an electrolytic solution. The device according to any one of -27.   29. The apparatus according to claim 28, wherein at least one of the hydrogen generator and the oxygen generator is a porous conductor carrying a catalyst.   30. The apparatus according to claim 28 or 29, wherein the hydrogen generation catalyst includes at least one of Pt, Ir, Ru, Pd, Rh, Au, Fe, Ni, and Se.   The apparatus according to any one of claims 28 to 30, wherein the oxygen generation catalyst includes at least one of Mn, Ca, Zn, Co, and Ir. A second substrate is further provided on the first electrolysis electrode and the second electrolysis electrode,
The device according to claim 11, wherein the second substrate includes the side wall portion. The gas production apparatus according to any one of claims 11 to 32 is installed such that a light receiving surface of the photoelectric conversion unit is inclined with respect to a horizontal plane,
An electrolyte is introduced into the gas production apparatus from the lower part of the gas production apparatus, and sunlight is made incident on the light receiving surface of the photoelectric conversion unit, whereby the first gas and the second electrolysis electrode are respectively supplied to the first gas and A gas production method for generating a second gas and discharging the first gas and the second gas from an upper part of the gas production apparatus.