JP5427653B2 - Gas production apparatus and gas production method - Google Patents

Description

  The present invention relates to a gas production apparatus and a gas production method.

  In recent years, the use of renewable energy, which is friendly to the environment and has an inexhaustible energy supply, has attracted attention due to concerns about global warming associated with the use of fossil fuels and the depletion of fossil fuel resources themselves. Has been done. Renewable energies include sunlight, wind power, hydropower, geothermal heat, etc., and technologies for generating electric power using these energies have been put into practical use. In particular, sunlight is an energy source that can be obtained anywhere on the ground, and solar cells that generate electricity from sunlight are installed in various parts of the world, and nowadays, although they are still few, they are spreading to ordinary households. However, there is a drawback that the energy supply by sunlight is not constant due to seasonal and climate fluctuations, and it is a problem to smooth this fluctuation. As one method for solving this problem, a method of converting energy obtained from the sun into another substance, for example, liquid fuel, gas such as hydrogen, and the like is conceived.

Among these conversion materials from solar energy, hydrogen is expected to be a future energy because it only produces water when burned, and does not emit carbon dioxide or harmful nitrogen oxides that cause global warming. . As for hydrogen gas generation, a method of generating from fossil fuel such as methane and a method of generating water by electrolysis are tried, but the latter without CO ₂ emission is the final means, and among them stable It is said that hydrogen gas generation by electrolysis of water using solar power generation is the most reliable means as a general and regional universal means. As a result, solar energy can be stored as chemical energy, and the range of use of solar energy is greatly expanded.

  In addition, hydrogen gas generation by photocatalyst (Honda Fujishima effect) has been studied as a method of generating hydrogen more directly from solar energy, but the ultraviolet region that currently accounts for only about 3% of solar energy. However, there is a problem that only the light can be used. Other attempts have been made to generate hydrogen by thermal decomposition of water using nuclear power or hydrogen gas using biomass, but it is still in the research stage.

  Conventionally, there is a water electrolysis system using sunlight as shown in Patent Document 1, for example. In this water electrolysis system, a photoelectrochemical cell in which a layer of a photocatalyst is laminated on a photoelectric conversion semiconductor is installed vertically, and water can be directly decomposed by irradiating light. In Patent Document 2, a p-type semiconductor and an n-type semiconductor are stacked on a conductor, and the semiconductors are stacked in reverse order on the same surface separated by an insulating member. It is shown that it can be generated with In addition, there is something as shown in Patent Document 3. In this water electrolysis system, a photocatalyst layer and a counter electrode are provided via an ion conductive membrane. Also, a flow hole is provided in the outer wall of the water electrolysis cell so that the electrolyte can flow between adjacent water electrolysis cells via the flow hole, preventing electrical continuity between adjacent water electrolysis cells. Like to do. The water decomposition cell is installed in an inclined state, and water is decomposed by irradiating light. Moreover, the utilization efficiency of sunlight is made high by installing the water splitting cell in an inclined state.

Special table 2004-504934 gazette JP 2004-197167 A JP 2008-75097 A

However, in the conventional water splitting system, when the water splitting reaction surface is installed on a vertical surface, the generated gas is unlikely to rise as bubbles and is likely to stay on the water splitting reaction surface. In addition, when the water splitting reaction surface is installed obliquely in order to increase the use efficiency of sunlight, the gas generated on the water splitting reaction surface on the light receiving surface side tends to float as bubbles and stays on the water splitting reaction surface. However, on the water splitting reaction surface on the opposite side of the light receiving surface, the generated gas is unlikely to rise as bubbles, and the generated gas tends to stay. For this reason, the area of the water splitting reaction surface in contact with water is reduced, and the water splitting efficiency is lowered.
The present invention has been made in view of such circumstances, and provides a gas production apparatus that can suppress the retention of gas generated from an electrolyte solution on the reaction surface and has high gas generation efficiency.

  The present invention provides a photoelectric conversion unit having a light receiving surface and a back surface, and a first gas that is electrically connected to the back surface and generates an first gas from an electrolyte using an electromotive force generated when the photoelectric conversion unit receives light. A gas generator, a second gas generator that is electrically connected to the light receiving surface, and generates a second gas from the electrolyte using an electromotive force generated by the photoelectric conversion unit receiving light; and a gas flow path; The gas flow path is provided between at least one of the first gas generation unit and the second gas generation unit and the back surface of the photoelectric conversion unit, A gas production apparatus is provided, wherein one gas or a second gas is conducted to the gas discharge port.

According to the present invention, the gas flow path is provided between at least one of the first gas generation part and the second gas generation part and the back surface of the photoelectric conversion part, and the gas flow path is a first gas. Alternatively, since the second gas is conducted to the gas discharge port, the retention of the first gas on the surface of the first gas generation unit or the retention of the second gas on the surface of the second gas generation unit can be suppressed. . Further, the first gas or the second gas can be quickly discharged from the gas discharge port and can be recovered. That is, when the gas production apparatus of the present invention is installed obliquely, the first gas or the second gas generated from the electrolyte in the first gas generation part or the second gas generation part on the opposite side of the light receiving surface is caused by the buoyancy. Surface. By this buoyancy, the first gas or the second gas can flow into the gas flow path, and the first gas or the second gas can be conducted through the gas flow path and recovered from the gas discharge port. For this reason, it can suppress that 1st gas stagnates on the surface of a 1st gas generation part, or 2nd gas stagnates on the surface of a 2nd gas generation part, and decomposes | disassembles electrolyte solution efficiently and is 1st. A gas or a second gas can be generated. Further, the generated first gas or second gas can be quickly recovered, and the responsiveness from light irradiation to product gas recovery can be improved.
According to the present invention, since the retention of gas can be suppressed by providing the first gas flow path, there is no need to attach an additional device for convection of the electrolytic solution or an additional device for vibrating the entire device. The gas production apparatus can be reduced in size.

It is a schematic plan view which shows the structure of the gas manufacturing apparatus of one Embodiment of this invention. It is a schematic back view which shows the structure of the gas manufacturing apparatus of one Embodiment of this invention. It is a schematic sectional drawing which shows the structure of the gas manufacturing apparatus of one Embodiment of this invention. It is a schematic sectional drawing which shows the structure of the gas manufacturing apparatus of one Embodiment of this invention. It is a schematic sectional drawing which shows the structure of the gas manufacturing apparatus of one Embodiment of this invention. It is a schematic sectional drawing which shows the structure of the gas manufacturing apparatus of one Embodiment of this invention. It is a schematic sectional drawing which shows the structure of the gas manufacturing apparatus of one Embodiment of this invention. It is an enlarged view of the range D enclosed with the dotted line of FIG. It is a schematic sectional drawing which shows the structure of the gas manufacturing apparatus of one Embodiment of this invention. It is a schematic sectional drawing which shows the structure of the gas manufacturing apparatus of one Embodiment of this invention. It is an enlarged view of the range E enclosed with the dotted line of FIG. It is a schematic sectional drawing which shows the structure of the gas manufacturing apparatus of one Embodiment of this invention. It is an enlarged view of the range F enclosed with the dotted line of FIG. It is a schematic sectional drawing which shows the structure of the gas manufacturing apparatus of one Embodiment of this invention. It is an enlarged view of the range G enclosed with the dotted line of FIG. It is a schematic sectional drawing which shows the structure of the gas manufacturing apparatus of one Embodiment of this invention. It is an enlarged view of the range J enclosed with the dotted line of FIG. It is a schematic plan view which shows the structure of the gas manufacturing apparatus of one Embodiment of this invention. It is a schematic sectional drawing which shows the structure of the gas manufacturing apparatus of one Embodiment of this invention. It is a schematic sectional drawing which shows the structure of the gas manufacturing apparatus of one Embodiment of this invention. FIG. 21 is an enlarged view of a range M surrounded by a dotted line in FIG. 20. It is a schematic sectional drawing which shows the structure of the gas manufacturing apparatus of one Embodiment of this invention. It is an enlarged view of the range N enclosed with the dotted line of FIG. It is a schematic sectional drawing which shows the structure of the gas manufacturing apparatus created by the comparative example.

  The gas production apparatus of the present invention is configured to remove a first gas from an electrolyte solution using a photoelectric conversion unit having a light receiving surface and a back surface, and an electromotive force that is electrically connected to the back surface and received by the photoelectric conversion unit. A first gas generating unit to be generated, a second gas generating unit that is electrically connected to the light receiving surface and generates a second gas from the electrolytic solution using an electromotive force generated by the photoelectric conversion unit receiving light, A gas flow path and a gas discharge port, wherein the gas flow path is provided between at least one of the first gas generation unit and the second gas generation unit and the back surface of the photoelectric conversion unit, and the gas flow The path is characterized in that the first gas or the second gas is conducted to the gas outlet.

A gas production apparatus is an apparatus that can produce a first gas and a second gas from an electrolytic solution.
The photoelectric conversion part is a part that receives light and generates an electromotive force.
The light receiving surface is a surface of the photoelectric conversion unit on which light is incident.
The back surface is the back surface of the light receiving surface.

The gas manufacturing apparatus of the present invention further includes a first conductive unit, the first gas generation unit and the second gas generation unit are provided on the back surface of the photoelectric conversion unit, and the gas flow path is configured to generate the first gas. It is preferable that the second gas generation unit is electrically connected to the light receiving surface via the first conductive unit, and the second gas generation unit is provided between the back surface and the second gas generation unit. .
According to such a configuration, light can be incident on the light receiving surface without using 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. In addition, light incident on the light receiving surface is not absorbed or scattered by the first gas generation unit, the second gas generation unit, the first gas, and the second gas. 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, it is preferable that an insulating part is further provided, and the second gas generating part is provided on the back surface of the photoelectric conversion part via the insulating part.
According to such a configuration, according to such a configuration, it is possible to prevent a leak current from flowing between the second gas generation unit and the back surface of the photoelectric conversion unit.

In the gas manufacturing apparatus of the present invention, the first conductive part includes a first electrode that contacts the light receiving surface of the photoelectric conversion part, and a second conductive part that contacts the first electrode and the second gas generation part, respectively. Is preferred.
According to such a configuration, the light receiving surface of the photoelectric conversion unit and the second gas generation unit can be electrically connected, and the second gas can be generated more efficiently.
In the gas manufacturing apparatus of the present invention, the photoelectric conversion unit may have a first contact hole that penetrates from the back surface to the light receiving surface, and the second conductive unit may be provided in the first contact hole that penetrates the photoelectric conversion unit. preferable.
According to such a configuration, the first electrode and the second gas generation unit can be electrically connected, and the reduction in the area of the light receiving surface of the photoelectric conversion unit due to the provision of the second conductive unit is reduced. Can do.

In the gas production apparatus of the present invention, it is preferable that the gas production apparatus further includes a translucent substrate, and the photoelectric conversion unit is provided on the translucent substrate.
According to such a structure, the photoelectric conversion part which needs to be formed on a board | substrate is applicable to the gas manufacturing apparatus of this invention. Moreover, the gas manufacturing apparatus of this invention can be made easy to handle.
In the gas manufacturing apparatus of the present invention, it is preferable to further include a gas branch channel, the gas branch channel is formed by either one of the first gas generation unit and the second gas generation unit, and is connected to the gas channel, It is preferable that the gas branch channel conducts the first gas or the second gas to the gas channel.
According to such a configuration, the first gas generated by the first gas generation unit or the second gas generated by the second gas generation unit can be made to flow through the gas branch channel and flow into the gas channel. . As a result, the retention of the first gas on the surface of the first gas generation part or the retention of the second gas on the surface of the second gas generation part can be suppressed, and the electrolytic solution is efficiently decomposed and the first gas and A second gas can be generated. In addition, even when the first gas generation unit or the second gas generation unit is made of a material that does not transmit gas such as a metal plate, the first gas or the second gas can flow into the gas flow path. Alternatively, the retention of the second gas can be suppressed.

In the gas manufacturing apparatus of the present invention, there are a plurality of first gas generation units or second gas generation units, and the gas branch channel is between two adjacent first gas generation units or two adjacent second gas generation units. It is preferable to be provided between.
According to such a configuration, it is possible to easily form a gas branch channel between two adjacent first gas generating portions or by forming two adjacent second gas generating portions. Alternatively, the gas branch channel can be easily formed by forming one first gas generating part or one second gas generating part and forming the dividing groove.
In the gas manufacturing apparatus of the present invention, the gas branch channel has a first opening and a second opening at both ends, and the first opening is one of the first gas generation part and the second gas generation part. The second opening is provided on a surface opposite to the surface provided with the first opening, and the second opening has a first edge and a second edge having different heights. And it is preferable that a 1st edge is an edge of 2nd opening higher than a 2nd edge, and makes 1st gas or 2nd gas flow in into a gas branch flow path.
According to such a configuration, since the gas branch channel has the first opening and the second opening, the gas branch channel is generated in the vicinity of the surface opposite to the gas channel side surface of the first gas generation unit or the second gas generation unit. The first gas or the second gas can also be caused to flow through the gas flow path through the gas branch flow path. The second opening has a first edge and a second edge having different heights, and the first edge is an edge of the second opening that is higher than the second edge. The first gas or the second gas generated in the vicinity of the surface on the opposite side of the surface on the gas flow path of the second gas generating portion is likely to flow in through the gas branch flow path. As a result, the retention of the first gas or the second gas can be suppressed, and the decomposition efficiency of the electrolytic solution can be increased.

In the gas production apparatus of the present invention, one of the first gas and the second gas is preferably H ₂ and the other is preferably O ₂ .
According to such a configuration, it is possible to degrade the water contained in the electrolytic solution, to produce and H ₂ as a fuel.
In the gas manufacturing apparatus of the present invention, it is preferable that the gas flow path is provided along the back surface of the photoelectric conversion unit.
According to such a configuration, the first gas or the second gas can be easily flown into the gas flow path, and the first gas or the second gas can be easily recovered from the gas discharge port.

The gas production apparatus of the present invention further includes an electrolyte chamber, and at least one of the first gas generation unit and the second gas generation unit is provided between the back surface of the photoelectric conversion unit and the electrolyte chamber, And it is preferable that it can be immersed in electrolyte solution.
According to such a configuration, the first gas generation unit or the second gas generation unit can be immersed in the electrolytic solution, and in the first gas generation unit or the second gas generation unit, the first gas or the second gas is generated from the electrolytic solution. Two gases can be generated.

In the gas manufacturing apparatus of the present invention, it is preferable that the gas flow path is provided so that any one of the first gas and the second gas can flow in by buoyancy.
According to such a configuration, the first gas or the second gas can flow into the gas flow path, and the first gas stays on the surface of the first gas generation unit or the second gas generation unit of the second gas. It is possible to suppress the retention on the surface.

In the gas manufacturing apparatus of the present invention, it is preferable that a gas conduction part is further provided between at least one of the first gas generation part and the second gas generation part and the photoelectric conversion part. It is preferable to have a path.
According to such a configuration, the gas flow path can be easily provided.
In the gas manufacturing apparatus of the present invention, it is preferable that the gas conduction part is formed of a porous material.
According to such a structure, the hole which a porous material has can be made into a gas flow path.
In the gas manufacturing apparatus of the present invention, it is preferable that the gas conduction part has a hydrophobic surface.
According to such a configuration, the stagnation of the first gas or the second gas can be suppressed, and the decomposition efficiency of the electrolytic solution can be increased.

In the gas production apparatus of the present invention, it is preferable that the gas conduction part is formed of a superhydrophobic porous film.
According to such a structure, the hole which the electrolyte solution which a hydrophobic porous membrane has does not flow in can be made into a gas flow path. By using the hole not filled with the electrolytic solution as a gas flow path, the gas flow path can be quickly conducted in a state where the first gas or the second gas is not a bubble. As a result, the retention of the first gas or the second gas can be suppressed, and the decomposition efficiency of the electrolytic solution can be increased. In addition, this makes it possible to shorten the time for recovering the first gas and the second gas from the irradiation of light to the photoelectric conversion unit, improve the responsiveness, and the first gas and the second gas. The recovery efficiency can be improved.
In the gas manufacturing apparatus of the present invention, the first gas generation unit and the second gas generation unit are provided on the back surface, and the gas conduction unit includes the back surface, the first gas generation unit, and the second gas generation unit. It is preferably provided between and having corrosion resistance and liquid shielding properties against the electrolytic solution.
According to such a structure, a photoelectric conversion part and electrolyte solution can be isolate | separated by a gas conduction | electrical_connection part, and it can prevent that a photoelectric conversion part contacts an electrolyte solution. Accordingly, for example, the photoelectric conversion unit can be prevented from being corroded by the electrolytic solution, and a decrease in photoelectric conversion efficiency due to the inflow of the electrolytic solution to the photoelectric conversion unit can be prevented.

In the gas manufacturing apparatus of the present invention, it is preferable that the gas conduction part is provided so as to cover the photoelectric conversion part.
According to such a structure, a photoelectric conversion part and electrolyte solution can be isolate | separated by a gas conduction | electrical_connection part.
In the gas manufacturing apparatus of the present invention, it is preferable that the gas conduction part has conductivity.
According to such a configuration, the first gas generation unit and the back surface of the photoelectric conversion unit can be set to substantially the same potential, or the second gas generation unit and the light receiving surface of the photoelectric conversion unit are set to substantially the same potential. can do. Thereby, the decomposition efficiency of the electrolytic solution can be increased.

In the gas manufacturing apparatus of the present invention, the first gas generation unit and the second gas generation unit further include a third conductive unit that is provided on the back surface and electrically connects the back surface and the first gas generation unit. The gas conduction part is provided between the back surface and the first gas generation part, and has a second contact hole penetrating the gas conduction part, and the third conduction part is a second contact hole. It is preferable to be provided.
According to such a configuration, even when an insulator or a semiconductor is used for the gas conduction part, the back surface of the photoelectric conversion part and the first gas generation part can be set to substantially the same potential, and the decomposition efficiency of the electrolytic solution can be improved. Can be high.
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, the photoelectric conversion unit can have a pin structure, and photoelectric conversion can be performed efficiently. Moreover, the electromotive force generated in the photoelectric conversion unit can be increased, and the electrolytic solution can be electrolyzed more efficiently.

In the gas production apparatus of the present invention, one of the first gas generation unit and the second gas generation unit is a hydrogen generation unit that generates H ₂ from the electrolytic solution, and the other generates O ₂ from the electrolytic solution. It is an oxygen generation part, and it is preferable that the hydrogen generation part and the oxygen generation part include a catalyst for a reaction for generating H ₂ from the electrolytic solution and a catalyst for a reaction for generating O ₂ from the electrolytic solution, respectively.
According to such a configuration, it is possible to increase the reaction rate of the reaction in which H ₂ is generated from the electrolytic solution in the hydrogen generation unit that is one of the first gas generation unit and the second gas generation unit. It is possible to increase the reaction rate of the reaction in which O ₂ is generated from the electrolytic solution in the oxygen generation unit which is the other of the gas generation unit and the second gas generation unit. Thus, H ₂ can be more efficiently produced by the electromotive force generated in the photoelectric conversion unit, and the light utilization efficiency can be improved.
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, according to such a configuration, the catalyst surface area of at least one of the first gas generation unit and the second gas generation unit can be increased, and oxygen or hydrogen is generated more efficiently. Can be made. In addition, by using a porous conductor, a change in potential due to a current flowing between the photoelectric conversion unit and the catalyst can be suppressed, and hydrogen or oxygen can be generated more efficiently. Further, hydrogen or oxygen generated on the catalyst surface can be made to flow through the gas flow path through the hydrogen generation part or the hole of the oxygen generation part. Thereby, the retention of hydrogen in the hydrogen generation part or the retention of oxygen in the oxygen generation part can be suppressed.

In the gas production apparatus of the present invention, it is preferable that the hydrogen generation unit and the oxygen generation unit have a hydrophilic surface.
According to such a configuration, the contact area between the hydrogen generator and the oxygen generator and the electrolytic solution can be widened, and the electrolytic solution can be decomposed more efficiently. In addition, according to such a configuration, it is possible to suppress the hydrogen and oxygen generated in the hydrogen generation unit and the oxygen generation unit from staying in the state of bubbles for a long time, and the hydrogen and oxygen to the gas flow path can be suppressed. The delivery efficiency of can be improved.
In the gas production apparatus of the present invention, the first gas generation unit and the second gas generation unit are provided on the back surface of the photoelectric conversion unit, and the photoelectric conversion unit is provided on the translucent substrate, A top plate facing the translucent substrate is further provided on the gas generating unit and the second gas generating unit, and between the first gas generating unit and the top plate and between the second gas generating unit and the top plate. It is preferable that an electrolyte chamber is provided between each.
According to such a configuration, the electrolyte can be introduced into the electrolyte chamber between the first gas generator and the second gas generator and the top plate, and the first gas generator and the second gas generator. The first gas and the second gas can be more efficiently generated from the electrolytic solution in the part.

In the gas manufacturing apparatus of the present invention, it is preferable that the apparatus further includes a partition that partitions the electrolyte chamber between the first gas generator and the top plate and the electrolyte chamber between the second gas generator and the top plate. .
According to such a configuration, the first gas and the second gas generated in the first gas generation unit and the second gas generation unit can be separated, and the first gas and the second gas can be recovered more efficiently. can do.
In the gas production apparatus of the present invention, the partition preferably includes an ion exchanger.
According to such a configuration, the proton concentration imbalance between the electrolyte introduced into the space above the first gas generator and the electrolyte introduced into the space above the second gas generator is eliminated. The first gas and the second gas can be generated stably.

Further, in the present invention, the gas production apparatus of the present invention is installed so that the light receiving surface is inclined with respect to a horizontal plane, an electrolyte is introduced into the gas production apparatus from a lower part of the gas production apparatus, and sunlight is received by the light receiving surface. And a gas production method for generating the first gas and the second gas from the first gas generation unit and the second gas generation unit, respectively, and discharging the first gas and the second gas from the upper part of the gas production apparatus. provide.
According to the gas production method of the present invention, the first gas and the second gas can be produced at low cost using sunlight. In addition, by installing the gas production apparatus so that the light receiving surface is inclined with respect to the horizontal plane, it is possible to decompose the electrolyte using sunlight with high efficiency. It can be installed on a roof with a mark.

  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.

Configuration of Gas Production Apparatus FIG. 1 is a schematic plan view of a gas production apparatus according to an embodiment of the present invention. Note that the translucent substrate is omitted. FIG. 2 is a schematic back view of the gas production apparatus according to the embodiment of the present invention. The bottom plate of the outer box is omitted. FIGS. 3-6 is a schematic sectional drawing of the gas manufacturing apparatus of one Embodiment of this invention, respectively, and respond | corresponds to sectional drawing of the dotted line AA of the gas manufacturing apparatus shown in FIG. FIG. 7 is a schematic cross-sectional view of the gas production apparatus according to one embodiment of the present invention, and corresponds to the cross-sectional view taken along the dotted line CC of the gas production apparatus shown in FIG. FIG. 8 is an enlarged view of a range D surrounded by a dotted line in FIG. FIG. 9 is a schematic cross-sectional view of a gas production apparatus according to an embodiment of the present invention.

  The gas production apparatus 23 of the present embodiment uses a photoelectric conversion unit 2 having a light receiving surface and a back surface, and an electromotive force generated when the photoelectric conversion unit 2 receives light and is electrically connected to the back surface. A first gas generating section 8 that generates one gas; and a second gas that is electrically connected to the light receiving surface and generates a second gas from the electrolyte using an electromotive force generated when the photoelectric conversion section 2 receives light. The generator 7, the gas flow path 17, and the gas discharge ports 19 and 20 are provided. The gas flow path 17 includes at least one of the first gas generation section 8 and the second gas generation section 7 and the photoelectric conversion section 2. The gas flow path 17 is provided between the back surface and the back surface, and conducts the first gas or the second gas to the gas discharge ports 19 and 20.

In addition, the gas production apparatus 23 of the present embodiment further includes the translucent substrate 1, the first conductive unit 9, the second electrode 5, the insulating unit 11, the partition wall 13, the electrolyte chamber 15, the outer box 16, the water supply port 18, You may have the 1st gas exhaust port 20, the 2nd gas exhaust port 19, the gas conduction | electrical_connection part 21, the 3rd conduction | electrical_connection part 22, and the gas branch flow path 29. FIG.
The first conductive unit 9 may include the first electrode 4 and the second conductive unit 10. The outer box 16 may have a top plate 14.
Hereinafter, the gas production apparatus 23 of the present embodiment will be described.

1. Translucent substrate The translucent substrate 1 may be provided in the gas manufacturing apparatus 23 of the present embodiment. Further, for example, as shown in FIG. 3, the photoelectric conversion unit 2 may be provided on the translucent substrate 1 so that the light receiving surface is on the translucent substrate 1 side. In addition, when the photoelectric conversion part 2 consists of semiconductor substrates etc. and has fixed intensity | strength, the translucent 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 translucent substrate 1 can be omitted. Further, for example, when the first gas generation unit 8 and the second gas generation unit 7 are provided on the back surface and the light receiving surface of the photoelectric conversion unit 2 as shown in FIG. The electrolytic solution chamber 15 may be sandwiched between the conversion unit 2 and the like.

Moreover, the translucent board | substrate 1 may be 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, soda glass, quartz glass, borosilicate glass such as Pyrex (registered trademark), a transparent rigid material such as a synthetic quartz plate, or a plate made of polybutylene terephthalate (PBT) A transparent resin plate, a film material, or the like is preferably used. In view of chemical and physical stability and heat resistance, it is preferable to use a glass substrate such as quartz glass or Pyrex (registered trademark). Moreover, you may use what was processed for condensing, such as a Fresnel lens, in order to raise a condensing degree.
On the surface of the translucent substrate 1 on the photoelectric conversion unit 2 side, a fine uneven structure can be formed 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 Conductive Part The first conductive part 9 can electrically connect the second gas generating part 7 and the light receiving surface of the photoelectric conversion part 2. The first conductive portion 9 may be composed of one member, or may be composed of the first electrode 4 and the second conductive portion 10. By providing the first conductive portion 9, the potential of the light receiving surface of the photoelectric conversion portion 2 and the potential of the second gas generation portion 7 can be made substantially the same, and the second gas generation portion 7 generates the second gas. be able to.
Examples of the case where the first conductive portion 9 is made of one member include a metal wiring that electrically connects the light receiving surface of the photoelectric conversion portion 2 and the second gas generation portion 7. For example, it is a metal wiring made of Ag. Further, the metal wiring may have a shape like a finger electrode so as not to reduce light incident on the photoelectric conversion unit 2. The first conductive unit 9 may be provided on the photoelectric conversion unit 2 side of the translucent substrate 1 or may be provided on the light receiving surface of the photoelectric conversion unit 2.
Moreover, when the gas manufacturing apparatus 23 of this embodiment has a cross section like FIG. 9, the 1st electroconductive part 9 can also be abbreviate | omitted.

3. 1st electrode The 1st electrode 4 can be provided on the translucent board | substrate 1, and can be provided so that the light-receiving surface of the photoelectric conversion part 2 may be contacted. Moreover, the 1st electrode 4 may have translucency. Moreover, the 1st electrode 4 may be directly provided in the light-receiving surface of the photoelectric conversion part 2, when the translucent board | substrate 1 can be abbreviate | omitted. By providing the first electrode 4, the current flowing between the light receiving surface of the photoelectric conversion unit 2 and the second gas generation unit 7 can be increased.
Moreover, when the gas production apparatus 23 of this embodiment has a cross section as shown in FIG. 9, the first electrode 4 can be provided between the second gas generation unit 7 and the photoelectric conversion unit 2.

The first electrode 4 may be made of, for example, a transparent conductive film such as SnO ₂ , ZnO, In ₂ O _3, ITO (In ₂ O ₃ —SnO ₂ ), IZO (InSnO ₂ —ZnO), Ag, Au It may be made of a metal finger electrode.

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 gas generation unit 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.

4). Photoelectric Conversion Unit The photoelectric conversion unit 2 has a light receiving surface and a back surface, and the first gas generation unit 8 and the second gas generation unit 7 can be 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. Moreover, the photoelectric conversion part 2 can be provided on the translucent substrate 1 provided with the first electrode 4 with the light receiving surface facing down.
The photoelectric conversion unit 2 is not particularly limited as long as it can perform charge separation by incident light and generates an electromotive force between the light receiving surface and the back surface. For example, the photoelectric conversion unit using a silicon-based semiconductor, A photoelectric conversion unit using a compound semiconductor, a photoelectric conversion unit using a dye sensitizer, a photoelectric conversion unit using an organic thin film, and the like. Further, the photoelectric conversion unit 2 supplies holes and electrons necessary for the decomposition of the electrolytic solution to the first gas generation unit and the second gas generation unit. The potential difference between the light receiving surface and the back surface generated by the photoelectric conversion unit 2 receiving light can generate the first gas from the first gas generating unit and generate the second gas from the second gas generating unit. Although it will not specifically limit if it is possible, it can make it fully larger than the theoretical voltage for decomposing | disassembling electrolyte solution.

  When the first gas generation unit and the second gas generation unit are a hydrogen generation unit and an oxygen generation unit, respectively, when hydrogen and oxygen are generated after decomposing water contained in the electrolyte, the photoelectric conversion unit 2 emits light. It is necessary to use a material that generates an electromotive force necessary for generating hydrogen and oxygen in the hydrogen generation part and the oxygen generation part by receiving light. The potential difference between the hydrogen generation unit and the oxygen generation unit needs to be sufficiently larger than the theoretical voltage (1.23 V) for water splitting. This is because it is necessary to consider the hydrogen generation reaction in the hydrogen generation part and the overvoltage of the oxygen generation reaction in the oxygen generation part. For this purpose, it is necessary to generate a sufficiently large potential difference in the photoelectric conversion unit 2. For this reason, the photoelectric conversion unit 2 preferably connects two or more junctions in series such as a pn junction to generate an electromotive force.

  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.

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.

4-1. 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 an n-type impurity or p-type impurity is added is included, and crystalline, amorphous, microcrystalline, or polycrystalline silicon is also included.
In addition, the photoelectric conversion unit 2 using a silicon-based semiconductor may be a thin film or a thick photoelectric conversion layer formed on the translucent substrate 1, or a pn junction or a wafer such as a silicon wafer. A pin junction may be formed, or a thin film photoelectric conversion layer may be formed on a wafer having a pn junction or a pin junction.

As a method for manufacturing a photoelectric conversion unit using a silicon-based semiconductor, there is a plasma CVD method using a silicon sheet or amorphous heat treatment in the case of polycrystalline silicon and a silane gas or the like as a raw material in the case of amorphous silicon.
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 laminated on the translucent 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 , a polycrystalline or A 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 conductivity 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} conductivity type determining impurity atoms, or a polycrystalline or microscopic A crystalline 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.

4-2. Photoelectric conversion part using a 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 include those using a compound semiconductor of a chalcopyrite compound (I-III-VI ₂ etc.) which is a modification of the II-VI group. Compound semiconductors have a light absorption coefficient that is one to two orders of magnitude greater than that of silicon. Therefore, it is suitable for use as a thin film cell, and can be reduced in weight and cost.
For III-V compounds, for example, an n-type layer is epitaxially grown on the surface of a p-type doped GaAs wafer to produce a solar battery cell. Moreover, it is possible to make a GaAs-GaInP ₂ heterostructure by using GaInP ₂ which has good lattice matching with GaAs and does not contaminate GaAs, thereby further improving the conversion efficiency.
As for the II-VI group compounds, for example, CdTe-CdS heterostructures are industrialized at a low price. As a manufacturing method, it is manufactured by a screen method in which a paste is applied on a glass substrate and then baked. After a CdS film is formed on a glass substrate, CdTe is deposited in a comb shape. CdTe is an ideal solar cell material having a band gap of 1.44 eV, and CdS is a window material having a band gap of 2.42 eV and transmitting most of sunlight. In a heterojunction using a wide gap layer as a window material, light is transmitted through the window material and light is absorbed at the junction interface, so that generated carriers are efficiently separated and absorbed near the junction interface.
Examples of chalcopyrite compounds include Cu (In, Ga) Se ₂ (CIGS) (Copper Indium Gallium DiSelenide) and CuIn (S, Se) ₂ (CISS). For CIGS, the band gap is 1.55 eV to 1.6 eV, and as a production method, a method of forming a film on a glass plate coated with a Mo film by a ternary or quaternary vapor deposition method or a Cu-In film was formed. A selenization method in which heat treatment is performed in an atmosphere containing Se later is used.

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.

4-3. 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.

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

4-4. Photoelectric conversion part using organic thin film A photoelectric conversion part using an organic thin film comprises 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. It may be a laminate of a hole transport layer having an electron donating property.
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.

5. Second Electrode The second electrode 5 can be provided between the photoelectric conversion unit 2 and the first gas generation unit 8. By providing the second electrode 5, the potential of the back surface of the photoelectric conversion unit 2 and the potential of the first gas generation unit 8 can be made substantially the same. Moreover, the electric current which flows between the back surface of the photoelectric conversion part 2 and the 1st gas generation part 8 can be enlarged. Thus, the first gas can be generated more efficiently by the electromotive force generated in the photoelectric conversion unit 2. For example, when the conductive gas conduction part 21 is provided between the first gas generation part 8 and the photoelectric conversion part 2 as shown in FIG. 9, the second electrode 5 can be omitted, and the gas conduction part 21. By providing the same effect as the second electrode 5 can be obtained.

Further, for example, when the back surface of the photoelectric conversion unit 2 and the first gas generation unit 8 are electrically connected by the third conduction unit 22 as illustrated in FIG. 6, the third conduction unit 22 and the back surface of the photoelectric conversion unit 2 A second electrode can be provided to contact each. With this configuration, even when the insulating gas conduction unit 21 is provided, the potential of the back surface of the photoelectric conversion unit 2 and the potential of the first gas generation unit 8 can be made substantially the same.
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.

6). Insulating part The insulating part 11 can be provided between the back surface of the photoelectric conversion part 2 and the second gas generating part 7. Moreover, the insulating part 11 can also be provided between the first gas generating part 8 and the second gas generating part 7. Furthermore, the insulating part 11 is between the first conductive part 9 and the photoelectric conversion part 2, between the second conductive part 10 and the photoelectric conversion part 2, and between the second conductive part 10 and the second electrode 5. Can be provided. Moreover, when the gas manufacturing apparatus 23 of this embodiment has a cross section as shown in FIG. 9, the insulating part 11 can be omitted.
By providing the insulating unit 11, an electromotive force generated in the photoelectric conversion unit 2 causes a current to flow between the light receiving surface of the photoelectric conversion unit 2 and the second gas generation unit 7, and the back surface of the photoelectric conversion unit 2 and the first An electric current can flow between the gas generating unit 8 and the gas generating unit 8. Further, the leakage current can be further reduced. Thereby, the potential of the light receiving surface of the photoelectric conversion unit 2 and the potential of the second gas generation unit 7 can be made substantially the same, and the potential of the back surface of the photoelectric conversion unit 2 and the potential of the first gas generation unit 8 can be made. Can be made substantially the same, and the first gas and the second gas can be generated more efficiently.
For example, when providing the insulating gas conduction | electrical_connection part 21 between the 2nd gas generation part 7 and the photoelectric conversion part 2 like FIG. 6, between the 2nd gas generation part 7 and the photoelectric conversion part 2 is provided. The insulating part 11 can be omitted.

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.

7). Second Conductive Part The second conductive part 10 can be provided so as to be in contact with the first electrode 4 and the second gas generating part 7, respectively. By providing the second conductive portion 10, the first electrode 4 that is in contact with the light receiving surface of the photoelectric conversion portion 2 and the second gas generating portion 7 can be easily electrically connected. Moreover, when the gas manufacturing apparatus 23 of this embodiment has a cross section like FIG. 9, the 2nd electroconductive part 10 can be abbreviate | omitted.
Since the second conductive unit 10 contacts the first electrode 4 in contact with the light receiving surface of the photoelectric conversion unit 2 and the second gas generation unit 7 provided on the back surface of the photoelectric conversion unit 2, the light reception of the photoelectric conversion unit 2. If the cross-sectional area of the second conductive portion parallel to the surface is too large, the area of the light receiving surface of the photoelectric conversion portion 2 is reduced. Further, if the cross-sectional area of the second conductive unit 10 parallel to the light receiving surface of the photoelectric conversion unit 2 is made too small, a difference occurs between the potential of the light receiving surface of the photoelectric conversion unit 2 and the potential of the second gas generating unit 7. In some cases, a potential difference for decomposing the electrolytic solution cannot be obtained, and the generation efficiency of the first gas or the second gas may be reduced. Therefore, the cross-sectional area of the second conductive part parallel to the light receiving surface of the photoelectric conversion part 2 needs to be within a certain range. For example, the cross-sectional area of the second conductive part parallel to the light-receiving surface of the photoelectric conversion unit 2 (the total of the cross-sectional areas when there are a plurality of second conductive parts) is 100% of the area of the light-receiving surface of the photoelectric conversion unit 2 In this case, it can be 0.1% or more and 10% or less, preferably 0.5% or more and 8% or less, and more preferably 1% or more and 6% or less.

The second conductive unit 10 may be provided in a contact hole that penetrates the photoelectric conversion unit 2. Thereby, the reduction in the area of the light receiving surface of the photoelectric conversion unit 2 due to the provision of the second conductive unit 10 can be further reduced. Moreover, by this, the electric current path between the light-receiving surface of the photoelectric conversion part 2 and the 2nd gas generation part 7 can be shortened, and a 2nd gas can be generated more efficiently. In addition, this makes it possible to easily adjust the cross-sectional area of the second conductive unit 10 parallel to the light receiving surface of the photoelectric conversion unit 2.
In addition, the contact hole provided with the second conductive portion 10 may be one or more, and may have a circular cross section. The cross-sectional area of the contact hole parallel to the light-receiving surface of the photoelectric conversion unit 2 (the sum of the cross-sectional areas when there are a plurality of contact holes) is 0 when the area of the light-receiving surface of the photoelectric conversion unit 2 is 100%. .1% or more and 10% or less, preferably 0.5% or more and 8% or less, more preferably 1% or more and 6% or less.

  The material of the 2nd electroconductive part 10 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.

8). Gas Channel The gas channel 17 is provided between at least one of the first gas generation unit 8 and the second gas generation unit 7 and the photoelectric conversion unit 2. Moreover, the gas flow path 17 conducts the first gas generated by the first gas generator 8 or the second gas generated by the second gas generator 7 to the gas outlet. The gas flow path 17 is a cavity through which gas can be conducted, and may be filled with an electrolytic solution or may not be filled with an electrolytic solution.
The gas flow path 17 is not particularly limited as long as the generated first gas or second gas can be conducted. For example, the first gas generation unit 8 or the second gas generation unit 7 and the photoelectric conversion unit 2 It may be a cavity formed between them or a cavity included in the gas conduction part 21. In addition, the description about the gas conduction | electrical_connection part 21 is mentioned later.
By providing the gas flow path 17, retention of the first gas in the first gas generation unit 8 or retention of the second gas in the second gas generation unit 7 can be suppressed. This will be described with reference to the drawings.

  10 and 12 are schematic cross-sectional views when a gas production apparatus having a cross section as shown in FIG. 4 is installed obliquely, the electrolytic solution chamber 15 is filled with the electrolytic solution 25, and light is irradiated from the light receiving surface side. . 10 corresponds to a schematic cross-sectional view taken along one-dot chain line BB of the gas production apparatus 23 shown in FIG. 1, and FIG. 12 is a schematic cross-section taken along a dotted line CC of the gas production apparatus 23 shown in FIG. Corresponds to the figure. 11 is an enlarged view of a range E surrounded by a dotted line in FIG. 10, and FIG. 13 is an enlarged view of a range F surrounded by a dotted line in FIG.

  When the photoelectric conversion unit 2 included in the gas production apparatus shown in FIGS. 10 and 12 is irradiated with light, a potential difference is generated between the light receiving surface and the back surface of the photoelectric conversion unit 2 and is electrically connected to the light receiving surface. A potential difference is also generated between the second gas generator 7 and the first gas generator 8 electrically connected to the back surface. Due to this potential difference, a decomposition reaction of the electrolytic solution 25 occurs, the first gas is generated in the first gas generation unit 8, and the second gas is generated in the second gas generation unit 7. The generated gas 27, which is the generated first gas or the second gas, rises due to its buoyancy as shown in FIG. 11 or FIG. 13, and conducts through the gap between the first gas generating unit 8 or the second gas generating unit 7, It can be caused to flow into the gas flow path 17. The generated gas 27 flowing into the gas flow path 17 is conducted through the gas flow path 17 and can be taken out of the gas production apparatus 23 from the first gas discharge port 20 and the second gas discharge port 19 and collected. it can. In the case of the gas production device 23 shown in FIGS. 10 to 13, the gas flow path 17 is included in the gas conduction unit 21.

  Although the gas flow path 17 may be contained in the gas conduction | electrical_connection part 21 like FIGS. 10-13, for example, like the sectional view of the gas manufacturing apparatus 23 shown in FIG. It may be a groove-shaped cavity formed between the photoelectric conversion units 2 or between the second gas generation unit 7 and the photoelectric conversion unit 2. In the case of the gas production apparatus as shown in FIG. 3, the gas conduction part 21 is not formed, and the gas flow path 17 is, for example, the photoelectric conversion part 2, the insulating part 11, the first gas generation part 8, or the second gas generation part 7. It may be a hollow portion formed in a groove shape. Further, the hollow portion may be formed so as to be connected to the first gas exhaust port 20 or the second gas exhaust port 19.

Further, for example, as shown in FIG. 5, such a cavity portion formed in a groove shape connected to the first gas discharge port 20 or the second gas discharge port 19 may be provided in the gas conduction portion 21.
FIG. 14 is a schematic cross-sectional view when a gas production apparatus having a cross section as shown in FIG. 5 is installed obliquely, the electrolytic solution chamber 15 is filled with the electrolytic solution 25, and light is irradiated from the light receiving surface side. 14 corresponds to a schematic cross-sectional view taken along one-dot chain line BB of the gas production apparatus 23 shown in FIG. FIG. 15 is an enlarged view of a range G surrounded by a dotted line in FIG.
In the case of the gas production apparatus 23 as shown in FIG. 14, the generated gas 27 generated in the first gas generating unit 8 rises due to its buoyancy as shown in FIG. 15, and conducts through the gaps of the first gas generating unit 8. It can flow into the flow path 17. The generated gas 27 that has flowed into the gas flow path 17 is conducted through the gas flow path, and can be taken out from the first gas discharge port 20 to the outside of the gas production apparatus 23 and can be recovered.
Moreover, the groove-shaped gas flow path 17 can be provided so that it may go to the 1st gas exhaust port 20 from the edge part of the gas conduction | electrical_connection part 21 like FIG. Similarly, it can be provided so as to go from the end of the gas conduction part 21 toward the second gas discharge port 19. Thereby, the gas recovery efficiency can be further increased. The cross-sectional shape of the groove-like gas flow path 17 is preferably a circular shape or an arc shape from the viewpoint of the strength of the layer, but the gas recovered from the first gas generation unit 8 or the second gas generation unit 7 is the first. There is no particular limitation as long as it can be smoothly delivered to the first gas outlet 20 or the second gas outlet 19.

  Moreover, the gas flow path 17 can be provided between the back surface of the photoelectric conversion unit 2 and the first gas generation unit 8, and between the back surface of the photoelectric conversion unit 2 and the second gas generation unit 7, respectively. The two gas flow paths 17 can be prevented from conducting to each other. As a result, the gases generated by the first gas generation unit 8 and the second gas generation unit 7 can be recovered without being mixed. Means for preventing the gas flow path 17 between the first gas generation unit 8 and the back surface and the gas flow path 17 between the second gas generation unit 7 and the back surface from being connected to each other is not particularly limited. By providing the partition wall 13 or the insulating part 11 between the two gas flow paths 17, it is possible to prevent conduction.

For example, when the 2nd gas generation part 7 and the 1st gas generation part 8 are each provided in the light-receiving surface side and back surface side of the photoelectric conversion part 2 like FIG. 9, the gas flow path 17 is 1st. It can be provided between the gas generating unit 8 and the back surface of the photoelectric conversion unit 2.
FIG. 16 is a schematic cross-sectional view when a gas production apparatus having a cross section as shown in FIG. 9 is installed obliquely, the electrolytic solution chamber 15 is filled with the electrolytic solution 25, and light is irradiated from the light receiving surface side. FIG. 17 is an enlarged view of a range J surrounded by a dotted line in FIG.
In the case of the gas production apparatus 23 as shown in FIG. 16, the generated gas 27 generated in the first gas generating unit 8 rises due to its buoyancy as shown in FIG. It can flow into the flow path 17. The generated gas 27 that has flowed into the gas flow path 17 is conducted through the gas flow path 17, can be taken out of the gas production apparatus 23 from the first gas discharge port 20, and can be recovered. The generated gas 27 generated in the second gas generating unit 7 can be desorbed as bubbles from the second gas generating unit 7 by its buoyancy, and can be recovered from the second gas discharge port 19.

  The gas flow path 17 can have a hydrophilic or hydrophobic inner wall. When the gas flow path 17 is filled with the electrolyte, and the inner wall of the gas flow path 17 is hydrophilic, the generated gas 27 that is conducted as bubbles is difficult to be adsorbed on the inner wall of the gas flow path 17 and the gas flow The path 17 can be conducted. Thus, the generated gas 27 can be recovered from the first gas outlet 20 or the second gas outlet 19 with high responsiveness. In this case, the diameter of the gas flow path can be increased so that the generated gas 27 can be easily conducted as bubbles, and the gas flow path can be grooved.

  Further, when the gas flow path 17 is filled with the electrolytic solution and the inner wall of the gas flow path 17 is hydrophobic, the generated gas 27 pushes out the electrolytic solution and fills the gas flow path 17 with the generated gas 27. be able to. When the gas flow path 17 is filled with the generated gas 27, the generated gas 27 generated in the first gas generating section 8 or the second gas generating section 7 can be conducted through the generated gas 27 filling the gas flow path. It can be quickly recovered from the first gas outlet 20 or the second gas outlet 19. In this case, the volume of the gas channel 17 can be reduced. As a result, the gas channel 17 can be quickly filled with the generated gas 27, and the generated gas can be recovered more quickly.

  Further, when the inner wall of the gas flow path 17 is hydrophobic and the gas flow path 17 is not filled with the electrolytic solution, the generated gas 27 generated in the first gas generation section 8 or the second gas generation section 7 is The cavity of the gas flow path 17 can be conducted and recovered quickly. For example, such a gas flow path 17 can be formed by forming the gas conduction part 21 with a hydrophobic porous film.

9. Gas Conducting Unit The gas conducting unit 21 can be provided between at least one of the first gas generating unit 8 and the second gas generating unit 7 and the photoelectric conversion unit 2. Further, the gas conduction part 21 has a gas flow path 17.
Although the gas conduction | electrical_connection part 21 will not be specifically limited if it has the gas flow path 17, For example, it can comprise with a porous material. In this case, the hole of the porous material becomes the gas flow path 17. Moreover, the gas conduction | electrical_connection part 21 can also be made into the structure filled with the lattice-like structure and the microparticles | fine-particles. In this case, the gap between these structures becomes the gas flow path 17. Moreover, the gas conduction | electrical_connection part 21 may form the groove-shaped gas flow path 17 like FIG.5, FIG.14, FIG.15.

  The gas conduction part 21 may or may not have conductivity, but preferably has conductivity. It is preferable that the gas conduction | electrical_connection part 21 has electroconductivity. By providing the gas conduction part 21 having conductivity between the photoelectric conversion part 2 and the second gas generation part 7, the light receiving surface of the photoelectric conversion part 2 and the second gas generation part 7 have substantially the same potential. Can do. Moreover, the back surface of the photoelectric conversion part 2 and the 1st gas generation part 8 are made into the substantially same electric potential by providing the gas conduction | electrical_connection part 21 which has electroconductivity between the photoelectric conversion part 2 and the 1st gas generation part 8. FIG. be able to.

  When the gas conduction part 21 does not have conductivity, the third conductive part 22 is formed in the second contact hole that penetrates the gas conduction part 21, and the back surface of the photoelectric conversion part 2 and the first gas generation part 8 are electrically connected. Can be connected. For example, it can be set as the gas manufacturing apparatus which has a cross section as shown in FIG. Thereby, even when the gas conduction part 21 does not have conductivity, the back surface of the photoelectric conversion part 2 and the potential of the first gas generation part 8 can be made substantially the same, and the electrolytic solution can be efficiently decomposed. Can do. Moreover, when the gas conduction | electrical_connection part 21 has insulation, the insulation part 11 between the 2nd gas generation | occurrence | production part 7 and the photoelectric conversion part 2 can be abbreviate | omitted like FIG.

  Moreover, the gas conduction | electrical_connection part 21 may be formed from the material which has a hydrophilic surface, and may be surface-treated so that it may have a hydrophilic surface. This is because the gas flow path 17 having a hydrophilic inner wall can be provided. Moreover, the gas conduction | electrical_connection part 21 may be formed from the material which has a hydrophobic surface, and may be surface-treated so that it may have a hydrophobic surface. This is because the gas flow path 17 having a hydrophobic inner wall can be provided.

  In the gas manufacturing apparatus in which the first gas generation unit 8 and the second gas generation unit 7 are provided on the back surface, the gas conduction unit 21 includes the back surface of the photoelectric conversion unit 2, the first gas generation unit 8, and the second gas generation unit 8. It may be provided between the gas generation part 7 and may have corrosion resistance and liquid shielding properties against the electrolytic solution. Moreover, the gas conduction | electrical_connection part 21 may be provided so that the photoelectric conversion part 2 may be covered. As a result, contact between the photoelectric conversion unit 2 and the electrolytic solution can be prevented, and a photoelectric conversion material or an electrolytic solution that is easily corroded by the electrolytic solution flows into the photoelectric conversion unit 2 so that the photoelectric conversion efficiency decreases. A photoelectric conversion material can be used.

  As the gas conduction part 21, for example, it is preferable to use a conductive porous material made of carbon or a metal such as aluminum, tungsten, or iron. However, by providing the third conductive portion 22 as shown in FIG. 6, it is also possible to use a non-conductive polymer such as polyethylene or ethylene propylene rubber (EPR) or a ceramic porous material such as alumina or zirconia. It is. In addition, the gas conducting portion 21 may be a superhydrophobic porous membrane such as Millipore Durapel membrane (registered trademark) made of polyvinylidene fluoride (PVDF). Thereby, the penetration of the electrolytic solution into the gas flow path 17 included in the gas conduction part 21 can be blocked, and the gas flow path 17 can be in a state not filled with the electrolytic solution. As a result, the first gas generated in the first gas generating unit 8 or the second gas generated in the second gas generating unit 7 can be conducted through the gas flow path 17 without the electrolyte solution, and the gas recovery is more efficient. It can be done well.

  Moreover, as the gas conduction | electrical_connection part 21, a nonelectroconductive metal oxide, a polymer | macromolecule, or a natural origin material may be sufficient, for example. Examples of the metal oxide porous material are porous oxides such as oxides of elements of groups 2, 3, 4, 12, 13 and 14 of the periodic table, for example, aluminum, zirconium, silicon, magnesium. And oxides of these and their mixtures, in particular anodized light metals, in particular aluminum or alloys thereof. The porous synthetic material is, for example, a fluororesin, polyethylene, ethylene propylene rubber (EPR), or a porous polyamide filler. In particular, the polyamide filler is a polyamide-12, polyamide-6 or copolyamide-6 / 12 filler, which is sold by the company Atofina under the trade name Orgasol®. Further, as natural porous materials, chalk, pumice, calcined clay, unglazed ceramic, gypsum, concrete, kieselguhr, silica gel, zeolite, hair and the like can be used.

10. First Gas Generation Unit The first gas generation unit 8 may be provided on the back surface of the photoelectric conversion unit 2. Thus, the first gas generation unit 8 does not block light incident on the photoelectric conversion unit 2. Further, the first gas generation unit 8 can be electrically connected to the back surface of the photoelectric conversion unit 2. Thereby, the electric potential of the back surface of the photoelectric conversion unit 2 and the electric potential of the first gas generation unit 8 can be made substantially the same, the electrolytic solution is decomposed by the electromotive force generated in the photoelectric conversion unit 2, and the first gas is Can be generated. Further, the first gas generation unit 8 can be provided so as not to contact the second gas generation unit 7. As a result, it is possible to prevent leakage current from flowing between the first gas generation unit 8 and the second gas generation unit 7. Further, the first gas generator 8 may be exposed to the electrolyte chamber 15. As a result, the first gas can be generated from the electrolytic solution on the surface of the first gas generator 8. In addition, a plurality of first gas generation units 8 may be provided.
The first gas generation unit 8 can be either a hydrogen generation unit or an oxygen generation unit. Thereby, the water contained in the electrolytic solution can be decomposed in the first gas generating section to generate hydrogen or oxygen.

11. Second Gas Generating Unit The second gas generating unit 7 may be provided on the back surface of the photoelectric conversion unit 2. Thus, the second gas generation unit 7 does not block light incident on the photoelectric conversion unit 2. Further, the second gas generation unit 7 is electrically connected to the light receiving surface of the photoelectric conversion unit 2 via the first conductive unit 9. Thus, the potential of the light receiving surface of the photoelectric conversion unit 2 and the potential of the second gas generation unit 7 can be made substantially the same, and the electrolytic solution is decomposed by the electromotive force generated in the photoelectric conversion unit 2 so that the second gas is removed. Can be generated. Further, the second gas generation unit 7 may be provided on the back surface of the photoelectric conversion unit 2 via the insulating unit 11. Further, the second gas generation unit 7 can be provided so as not to contact the first gas generation unit 8. This can prevent a leakage current from flowing. Further, the second gas generation unit 7 may be exposed to the electrolyte chamber 15. Thereby, the second gas can be generated from the electrolytic solution on the surface of the second gas generating unit 7. In addition, a plurality of second gas generation units 8 may be provided.
The second gas generation unit 8 can be either one of a hydrogen generation unit and an oxygen generation unit. Accordingly, water or oxygen can be generated by decomposing water contained in the electrolytic solution in the second gas generating section.

The 1st gas generation part 8 and the 2nd gas generation part 7 may have gas permeability. As a result, the first gas generated by the first gas generation unit 8 or the second gas generated by the second gas generation unit 7 can rise by the buoyancy and flow into the gas flow path 17. Thereby, the retention of the first gas or the second gas can be suppressed.
A method for imparting gas permeability is not particularly limited, but the first gas generation unit 8 and the second gas generation unit 7 may be formed using a porous material, or the first gas generation unit 8 and the second gas generation unit 7 may be formed. You may provide sparsely so that the gas generation part 7 may have a clearance gap, respectively.
Moreover, when the 1st gas generation part 8 and the 2nd gas generation part 7 do not have gas permeability, you may give gas permeability by forming the gas branch channel 29 mentioned later.

  Examples of the first gas generation unit and the second gas generation unit made of a porous material include a carbon porous body such as carbon cloth and carbon paper, or a porous valve metal mainly composed of aluminum, titanium, niobium, tantalum, or the like. Or the like as a carrier, and a catalyst supported by a supporting method.

  The 1st gas generation part 8 and the 2nd gas generation part 7 may have a hydrophilic surface. Thereby, the permeability of the electrolyte solution to the first gas generation unit 8 and the second gas generation unit 7 can be improved. As a result, the reaction for generating the first gas and the second gas from the electrolytic solution can be activated, and the gas generation efficiency can be improved.

  Moreover, since the 1st gas generation part 8 and the 2nd gas generation part 7 have a hydrophilic surface, the 1st gas generated as a bubble or the 2nd gas is the 1st gas generation part 8 or the 2nd gas generation part. 7 can be made difficult to adsorb on the surface. That is, since the electrolytic solution easily enters between the bubble and the first gas generation unit 8 or the second gas generation unit 7, the bubble is difficult to be adsorbed. As a result, the generated bubbles can be raised by the buoyancy and easily flow into the gas flow path. Therefore, the retention of the generated first gas in the first gas generation unit 8 or the retention of the second gas in the second gas generation unit 7 can be suppressed, and the generated first gas or second gas is supplied to the gas flow path 17. Can be quickly recovered via

  Although the method to give the hydrophilic surface to the 1st gas generation part 8 and the 2nd gas generation part 7 is not specifically limited, For example, the 1st gas generation part 8 and the 2nd using the material which has a hydrophilic surface. The gas generation unit 7 may be formed, or the first gas generation unit 8 and the second gas generation unit 7 may have a hydrophilic surface by performing a hydrophilic treatment. The hydrophilic treatment can be performed by, for example, ion sputtering.

FIG. 18 is a schematic plan view of a gas production apparatus according to an embodiment of the present invention. FIG. 19 is a schematic cross-sectional view of a gas production apparatus according to an embodiment of the present invention, and corresponds to the cross-sectional view taken along the dotted line KK in FIG. The first gas generation unit 8 and the second gas generation unit 7 may be arranged in parallel on the back surface of the photoelectric conversion unit 2. Further, at least one of the first gas generation unit 8 and the second gas generation unit 7 is plural and may be alternately arranged. For example, you may have a structure like FIG. Thereby, the current path between the light receiving surface of the photoelectric conversion unit 2 and the second gas generation unit 7 can be further shortened, and the second gas can be generated more efficiently. As a result, the portion where the first gas generating unit 8 and the second gas generating unit 9 are adjacent to each other increases, and the gap between the electrolyte near the first gas generating unit 8 and the electrolyte near the second gas generating unit 9 is increased. It is possible to shorten the distance that ions conduct. Moreover, the ion conduction path | route of the electrolyte solution or ion exchanger which this ion conducts ion can be increased, and the ratio of an ion conduction area | region can be enlarged. As a result, the concentration of conductive ions can be reduced. The ion is, for example, a proton.
This facilitates movement of ions in the electrolyte solution in the vicinity of the first gas generation unit 8 and the electrolyte solution in the vicinity of the second gas generation unit 9, and the ion concentration imbalance can be reduced. As a result, a decrease in gas generation rate can be prevented.

The first gas generation unit 8 and the second gas generation unit 7 may be provided on the back surface of the photoelectric conversion unit 2 and on the light receiving surface of the photoelectric conversion unit 2, respectively. With this configuration, the second conductive portion 10 can be omitted. The gas manufacturing apparatus of this embodiment may have a cross section as shown in FIG. 16, for example.
The gas manufacturing apparatus having a cross section as shown in FIG. 16 has a photoelectric conversion unit 2 having a light receiving surface and a back surface, a gas conduction unit 21 is stacked on the back surface, and a first gas generation unit 8 is further formed thereon. Are stacked. For example, as shown in FIG. 16, the second gas generation unit 7, the photoelectric conversion unit 2, the gas conduction unit 21, and the first gas generation unit 8 are sequentially stacked from the light receiving surface side, and the light receiving surface is inclined with respect to the horizontal plane. When installed, the first gas generation unit 8 is configured to be below the photoelectric conversion unit 2. In addition, the gas manufacturing apparatus as shown in FIG. 16 includes the photoelectric conversion unit 2, the second gas generation unit 7, the first gas generation unit 8, the gas conduction unit 21, the partition wall 13, the translucent substrate 1, and the outer box 16. The first gas discharge port 20, the second gas discharge port 19, and the water supply port 18 can be used, and the same components as those of the other embodiments can be used. However, since the second gas generation unit 7 is disposed on the light receiving surface side, it is necessary to transmit light to the photoelectric conversion unit 2. Therefore, the catalyst is directly applied to the photoelectric conversion unit 2 made of a semiconductive solar cell, or SnO ₂ , ZnO, TiO ₂ , In ₂ O _3, ITO (In ₂ O ₃ —SnO ₂ ), IZO (InSnO ₂ —ZnO), etc. It is preferable that the first electrode 4 having transparent conductivity is supported by a method such as an ion sputtering method, a spray method, a CVD method, a sol-gel method, or electrolytic deposition.

12 Hydrogen generating part The hydrogen generating part is a part that generates H ₂ from the electrolytic solution, and can be either the first gas generating part 8 or the second gas generating part 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 of generating H ₂ from the electrolytic solution, or this catalyst may be supported on a carrier. Further, the hydrogen generation unit may have a catalyst surface area larger than the area of the light receiving surface of the photoelectric conversion unit 2. Thereby, the reaction in which H ₂ is generated from the electrolytic solution can be set to a faster reaction rate. The hydrogen generation part may be a porous conductor carrying a catalyst. This can increase the catalyst surface area. In addition, a change in potential due to a current flowing between the light receiving surface or the back surface of the photoelectric conversion unit 2 and the catalyst included in the hydrogen generation unit can be suppressed. Moreover, when this hydrogen generating part is the first gas generating part 8, even if the second electrode is omitted, the potential change due to the current flowing between the back surface of the photoelectric conversion part 2 and the catalyst can be suppressed. it can.

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, Os, and Au having catalytic activity against hydrogen and alloys or compounds thereof, Fe, Ni, which constitutes an active center of hydrogenase that is a hydrogen generating enzyme, Se alloys or compounds, combinations thereof, and the like can be suitably 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. In addition, although it is preferable to use a hydrogen generation catalyst having a low theoretical overvoltage for hydrogen generation, there is no particular limitation as long as the overvoltage is low.

  Although it is possible to directly support the hydrogen generating catalyst on the back surface of the photoelectric conversion unit 2, the catalyst can be supported on a conductor in order to increase the reaction area and improve the gas generation rate. 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.

13. Oxygen generating part The oxygen generating part is a part that generates O ₂ from the electrolyte, and can be either the first gas generating part 8 or the second gas generating part 7. Further, the oxygen generation unit may include a reaction catalyst (oxygen generation catalyst) for generating O ₂ 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 in which O ₂ is generated from the electrolytic solution, or this catalyst may be supported on a carrier. Further, the oxygen generation unit may have a catalyst surface area larger than the area of the light receiving surface of the photoelectric conversion unit 2. Thereby, the reaction in which O ₂ is generated from the electrolytic solution can be set to a faster reaction rate. The oxygen generation part may be a porous conductor carrying a catalyst. This can increase the catalyst surface area. In addition, a change in potential due to a current flowing between the light receiving surface or the back surface of the photoelectric conversion unit 2 and the catalyst included in the oxygen generation unit can be suppressed. Further, when this hydrogen generating unit is the first gas generating unit 8, even if the second electrode is omitted, the potential change due to the current flowing between the back surface of the photoelectric conversion unit 2 and the catalyst can be reduced. it can. Furthermore, the oxygen generation unit may include at least one of Mn, Ca, Zn, Co, and Ir as an oxygen generation catalyst.

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, ruthenium oxide, cobalt oxide, and cobalt phosphate can be preferably used because they have low overvoltage and high oxygen generation efficiency.

  Although the oxygen generating catalyst can be directly supported on the light receiving surface or the back surface of the photoelectric conversion unit 2, the catalyst can be supported on a conductor in order to increase the reaction area and improve the gas generation rate. 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 “12. 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.

14 Gas Branch Channel The gas branch channel 29 is formed by one of the first gas generation unit 8 and the second gas generation unit 7 and is connected to the gas channel 17. Further, the gas branch channel 29 can conduct the first gas generated by the first gas generation unit or the second gas generated by the second gas generation unit to the gas channel 17. Accordingly, the first gas or the second gas can be quickly flowed into the gas flow path 17, and the retention of the first gas in the first gas generation unit 8 and the retention of the second gas in the second gas generation unit 7. Can be suppressed.
Further, the gas branch channel 29 may be a gap formed between the two first gas generation units 8, or may be a gap formed between the two second gas generation units 7. Good. Further, the gas branch channel 29 may be a gap formed between the two strip-shaped first gas generation sections 8, or a gap formed between the two strip-shaped second gas generation sections 7. It may be. Further, the gas branch channel 29 may be formed to extend in a direction perpendicular to the direction in which the generated bubbles rise.
As a result, the first gas or the second gas generated near the surface of the first gas generating unit 8 or the second gas generating unit 7 on the side opposite to the gas channel 17 side is made to flow through the gas branch channel 29 to flow the gas. It can flow into the channel 17. Further, by providing the gas branch channel 29, a material having no gas permeability such as a metal plate can be used for the first gas generation unit 8 or the second gas generation unit 7.
This will be described with reference to the drawings.

FIG. 20 is a schematic cross-sectional view when a gas production apparatus having a gas branch channel 29 is installed obliquely, the electrolyte chamber 15 is filled with the electrolyte solution 25, and light is irradiated from the light receiving surface side. 20 corresponds to a cross-sectional view taken along the dotted line CC of the gas production device 23 illustrated in FIG. FIG. 21 is an enlarged view of a range M surrounded by a dotted line in FIG.
The gas bubbles of the first gas or the second gas generated near the surface opposite to the gas flow path 17 side of the first gas generation section 8 or the second gas generation section 7 flow into the gas branch flow path 29 as shown in FIG. This bubble can flow into the gas flow path 17. Accordingly, it is possible to suppress the generated first gas from staying in the first gas generation unit 8 or the second gas from staying in the second gas generation unit 7.

  FIG. 22 is a schematic cross-sectional view when a gas production apparatus having a cross section as shown in FIG. 7 is installed obliquely, the electrolytic solution chamber 15 is filled with the electrolytic solution 25, and light is irradiated from the light receiving surface side. FIG. 22 corresponds to a cross-sectional view taken along the dotted line CC of the gas production device 23 shown in FIG. FIG. 23 is an enlarged view of a range N surrounded by a dotted line in FIG.

  The gas branch channel 29 has a first opening 31 and a second opening 32, and the first opening 31 is on the side of the gas channel 17 of either the first gas generation unit 8 or the second gas generation unit 7. The second opening 32 is provided on the surface opposite to the surface on which the first opening 31 is provided, and the second opening 29 is provided with the first edge 33 and the second edge having different heights. 34, and the first edge 33 is the edge of the second opening 32 higher than the second edge 34, and the first gas or the second gas generated in the first gas generation part at the first edge 33 The second gas generated in the generation unit may flow into the gas branch channel 29. By having such a configuration, the first gas or the second gas generated in the vicinity of the surface of the first gas generating unit 8 or the second gas generating unit 7 on the side opposite to the gas channel 17 side is supplied to the gas branch channel 29. Inflow can be made easier. More specifically, using FIG. 23, the generated gas 27 that floats on the electrolyte solution 25 side of the second gas generating unit 7 collides with the first edge 33, which is a higher edge, and flows into the gas branch channel 29. can do.

The method for forming the first edge portion 33 and the second edge portion 34 is not particularly limited. For example, a plurality of second gas generation portions 7 are provided with a gap as shown in FIGS. The surface of the gas generating unit on the side of the electrolyte chamber can be inclined with respect to the back surface of the photoelectric conversion unit 2 so that the first edge 33 and the second edge 34 can be formed. By inclining in this way, the lower corner of the inclination becomes the second edge 34, and the upper corner of the inclination can become the first edge 33. Thus, when the generated gas rises as a bubble along the surface of the second gas generating unit 7, the generated gas stops at the first edge 33 of the second gas generating unit 7 adjacent to the upper part of the second gas generating unit 7. Then, the bubbles flow into the gas branch channel 29. As a result, the bubbles can flow through the gas branch channel 29 and flow into the gas channel 17. Therefore, it can suppress that generated gas retains on the surface of the 2nd gas generating part 7 arranged more upwards.
In addition, the inclination angles provided in the first gas generation unit 8 and the second gas generation unit 7 are not particularly limited, but in order to suppress a small amount of gas retention on the reaction surface, 30 degrees or more with respect to the back surface of the photoelectric conversion unit 2. Is desirable.

Next, the gas branch channel 29 will be described more specifically.
The two first gas generators 8 and the two second gas generators 7 are stacked with a gap of about several hundred μm to 2 mm, respectively. By adopting this structure, the first gas generating part 8 or the second gas generating part 7 is a non-porous conductive material that does not allow electrolyte to pass through, such as a transparent conductive oxide film such as a metal plate, SnO ₂ , or ITO. Materials can be used. Further, even when the first gas generating unit 8 or the second gas generating unit 7 is formed using a porous material, not only the generated gas 27 is caused to flow into the gas flow path 17 through the holes of the porous material. The generated gas 27 slightly staying in the vicinity of the interface between the electrolytic solution 25 and the first gas generating unit 8 or the second gas generating unit 7 can be recovered by flowing into the gas channel 17 via the gas branch channel 29. Become.
In addition, with respect to the size of the first gas generation unit 8 or the second gas generation unit 7, the retention of the generated gas 27 becomes smaller as the reaction surface with the electrolytic solution of one first gas generation unit 8 or the second gas generation unit 7 becomes smaller. Therefore, it is preferable that the vertical width of one first gas generator 8 or the second gas generator 7 is about 2 to 5 cm.

15. Outer box The outer box 16 is not particularly limited as long as it can accommodate the photoelectric conversion unit 2, the first gas generation unit 8, the second gas generation unit 7, and the like and can form the electrolyte chamber 15. . The outer box 16 can have a top plate 14.
The outer box 16 desirably has heat resistance and corrosion resistance. The outer box 16 is preferably made of a steel material such as stainless steel or a synthetic resin such as a ceramic such as zirconia or alumina, a phenol resin, a melamine resin (MF), or a glass fiber reinforced polyamide resin.

16. The top plate 14 can be provided on the first gas generation unit 8 and the second gas generation unit 7 so as to face the translucent substrate 1. The top plate 14 can be provided such that an electrolyte chamber is provided between the first gas generation unit 8 and the second gas generation unit 7 and the top plate 14. The top plate 14 may be a part of the outer box 16.

  Moreover, the top plate 14 is a material that constitutes an electrolyte chamber and is configured 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 top plate 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.

17. Partition Wall The partition wall 13 can be provided so as to partition the electrolyte chamber between the first gas generator 8 and the top plate 14 and the electrolyte chamber between the second gas generator 7 and the top plate 14. The partition wall 13 is provided between the back surface of the photoelectric conversion unit 2 and the first gas generation unit 8, and between the back surface of the photoelectric conversion unit 2 and the second gas generation unit 7. The gas conducting part 21 can be provided so as to partition.
Thereby, it is possible to prevent the first gas generated by the first gas generation unit 8 and the second gas generated by the second gas generation unit 7 from being mixed, and the first gas and the second gas are mixed. It can be separated and recovered.
The partition wall 13 may include an ion exchanger. As a result, the electrolyte in the electrolyte chamber between the first gas generator 8 and the top plate 14 and the electrolyte in the electrolyte chamber between the second gas generator 7 and the top plate 14 are unbalanced. The ion concentration can be kept constant. In other words, the ion concentration can be eliminated through the partition wall 9, thereby eliminating the ion concentration imbalance. The ion is, for example, a proton.

In the case of generating hydrogen and oxygen from water contained in the electrolytic solution, the ratio of the hydrogen generation amount and the oxygen generation amount is a molar ratio of 2: 1, and the first gas generation unit 8 and the second gas generation unit 7 The amount of gas generated is different. Therefore, for the purpose of keeping the water content in the apparatus constant, the partition wall 13 is preferably made of a material that allows the electrolytic solution to pass therethrough. 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.
When hydrogen generation and oxygen generation are selectively performed by a hydrogen generation catalyst and an oxygen generation catalyst, respectively, and ion movement accompanying this occurs, it is not always necessary to arrange a member such as a special membrane for ion exchange. . For the purpose of only physically isolating the gas, it is possible to use an ultraviolet curable resin or a thermosetting resin described in a sealing material described later.

18. Sealing material The sealing material adheres the translucent substrate 1 and the top plate 14 or the outer box 16, and seals the electrolyte flowing in the gas production device 23 and the first gas and the second gas generated in the gas production device 23. It is a material to do. As the sealing material, 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, although it is described as a sealing material, it is not limited as long as it has a function of adhering the translucent substrate 1 to the top plate 14 or the outer box 16, and a screw or the like from the outside using a resin or metal gasket. It is also possible to appropriately use a method of increasing the confidentiality by physically applying pressure using the above member.

19. Electrolyte Chamber The electrolyte chamber 15 can be a space between the first gas generator 8 and the top plate 14 and a space between the second gas generator 7 and the top plate 14. The electrolyte chamber 15 can be partitioned by the partition wall 13.

20. The water supply port, the first gas discharge port, and the second gas discharge port The water supply port 18 can be provided by making an opening in a part of the sealing material or the outer box 16 included in the gas production device 23. The water supply port 18 is arranged to replenish the electrolytic solution decomposed into the first gas and the second gas, and the arrangement location and shape of the water supply port 18 can be efficiently supplied to the gas production apparatus. Although not particularly limited, it is preferably installed in the lower part of the gas production apparatus from the viewpoint of fluidity and ease of supply.

  The first gas discharge port 20 and the second gas discharge port 19 are provided in the seal material or the outer box 16 in the upper part of the gas production device 23 when the gas production device 23 is installed with the water supply port 18 on the lower side. It can be provided by making an opening. Moreover, the 1st gas exhaust port 20 and the 2nd gas exhaust port 19 can be provided in the 1st gas generation part 20 side and the 2nd gas generation part 19 side on both sides of the partition 13. Further, the first gas outlet 20 and the second gas outlet 19 can be provided adjacent to one end of the gas flow path 17. It is also possible to increase the efficiency of gas recovery by connecting the first gas exhaust port 20 or the second gas exhaust port 19 to an aspirator or the like installed outside.

  By providing the water supply port 18, the first gas discharge port 20, and the second gas discharge port 19 in this manner, the gas production device 23 is inclined with respect to the horizontal plane with the light receiving surface of the photoelectric conversion unit 2 facing upward. It can be installed such that 18 is on the lower side and the first gas outlet 20 and the second gas outlet 19 are on the upper side. By installing in this way, electrolyte solution can be introduce | transduced in the gas manufacturing apparatus 23 from the water supply port 18, and the electrolyte chamber 15 can be satisfy | filled with electrolyte solution. In this state, the first gas and the second gas can be continuously generated by the first gas generation unit and the second gas generation unit, respectively, by causing light to enter the gas manufacturing apparatus 23. The generated first gas and second gas can be separated by the partition wall 13, and the first gas and the second gas are conducted through the gas flow path 17, and the first gas outlet 20 and the second gas outlet 19 are provided. Can be recovered from.

21. Electrolytic Solution The electrolytic solution is an aqueous solution containing an electrolyte, such as a 0.1M H ₂ SO ₄ electrolytic solution, a 0.1M potassium phosphate buffer solution, and the like.

EXAMPLES The present invention will be described more specifically with reference to the following examples, but the present invention is not limited to the examples.
Example 1
A gas production apparatus having a cross section as shown in FIG. 4 was produced under the following conditions.
For the photoelectric conversion part 2, a compound semiconductor solar cell laminated with n-type doped GaAs and GaInP ₂ and p-type doped GaAs and GaInP ₂ was used. A quartz glass substrate having excellent light transmittance, heat resistance, and corrosion resistance was used as the light transmissive substrate 1. As a manufacturing method, a p-type GaInP ₂ film having a thickness of 0.1 μm is formed on the surface of the glass substrate coated with the first electrode 4 made of tin dioxide (SnO ₂ ) by MOCVD (metal organic vapor deposition). On top of this, p-type GaAs was deposited in a thickness of 3.0 μm, n-type GaAs was deposited in a thickness of 0.1 μm, and n-type GaInP ₂ was sequentially deposited in a thickness of 0.05 μm. Thereafter, ITO was laminated on the surface of the n-type GaInP ₂ layer at a substrate temperature of 250 ° C. by a sputtering method to a thickness of 0.1 μm. Thus, a semi-conductor solar cell having a hetero structure in which both sides of a GaAs pn junction were sandwiched between GaInP ₂ on a light-transmitting substrate 1 was fabricated.

Next, the hydrogen generating part that is the first gas generating part 8 uses platinum as a catalyst, and the oxygen generating part that is the second gas generating part 7 uses RuO ₂ (ruthenium dioxide) particles as the catalyst. Each was supported on a porous carbon plate by a sol-gel method. Also, nickel foam was used for the gas conduction part 21 sandwiched between the photoelectric conversion part 2 and the oxygen generation part.
Next, in order to form the insulating part 11 for insulating the gas conduction part 21 arranged between the contact hole which is the second conductive part 10 and the oxygen generation part from the photoelectric conversion part 2, a raw material is formed by a spin coating method. A polyimide film was prepared by coating and baking. Subsequently, the second conductive portion 10 is formed by applying an Ag paste onto the substrate by screen printing, and a porous carbon sheet supporting nickel foam and ruthenium dioxide is disposed thereon, and heat treatment is performed. went. As a result, the gas conduction part 21 and the oxygen generation part were formed on the second conductive part 10. Similarly, the hydrogen generation part and the gas conduction part 21 were laminated on the back surface of the photoelectric conversion part 2 separated by a diaphragm 13 made of a glass filter.

  The outer box 16 was formed by pressing a stainless steel plate to a desired size, and then provided with a first gas outlet 19, a second gas outlet 19, and a water inlet 18. The translucent board | substrate 1 which formed the photoelectric conversion part 2 etc. in the said outer box 16 was joined by the sealing material (epoxy resin), and the gas manufacturing apparatus was created.

(Example 2)
A gas production apparatus having a cross section as shown in FIG. 20 was produced under the following conditions.
The constituent materials and standards for each component of the apparatus are basically the same as those of the gas production apparatus of the first embodiment. However, it differs in the following points. First, in this embodiment, the hydrogen generation part and the oxygen generation part are made of a plurality of aluminum plates having a thickness of 3 mm and processed to have a vertical width of 3 cm, and the surface thereof is made of Pt or oxygen generation catalyst which is a hydrogen generation catalyst. A certain RuO ₂ was prepared in the same manner as in Example 1. Next, a plurality of hydrogen generators and oxygen generators were provided as shown in FIG. A gap of 2 mm serving as a gas branch channel 29 was provided between the two hydrogen generation units and between the two oxygen generation units.

(Example 3)
A gas production apparatus having a cross section as shown in FIG. 7 was produced under the following conditions.
The constituent materials and standards of each constituent element of the apparatus are basically the same as those of the gas production apparatus of the second embodiment. However, as shown in FIG. 7, the difference is that the surface (reaction surface) opposite to the surface of the gas conducting portion of the hydrogen generating portion and the oxygen generating portion is provided with an angle with respect to the surface of the gas conducting portion. Yes. The hydrogen generation part and the oxygen generation part were cut so that the reaction surface of each 2 cm-thick aluminum plate having a vertical width of 3 cm was formed at an angle of 30 degrees with respect to the surface of the gas conduction part 21. Thereafter, Pt as a hydrogen generation catalyst and RuO ₂ (film thickness 1 μm) as an oxygen generation catalyst were supported on the surface of the aluminum plate in the same manner as in Example 1. When the hydrogen generation unit or the oxygen generation unit was stacked on the gas conduction unit 21, a gap of 2 mm was provided between the two hydrogen generation units and between the two oxygen generation units.

Example 4
The gas production apparatus produced in Example 1 was installed obliquely with respect to the horizontal plane so that sunlight was irradiated perpendicularly to the translucent substrate 1. After supplying 0.1 M H ₂ SO ₄ electrolyte from the water supply port 18 to fill the electrolyte chamber 15, sunlight was irradiated.
Further, when the amount of gas recovered from the first gas outlet 20 and the second gas outlet 19 from the start of sunlight irradiation to two hours later was quantified by fluorescence sensor analysis, hydrogen and oxygen were recovered from each. It was confirmed that Moreover, as shown in Table 1 shown below, the amount of each gas was 0.41 mol of hydrogen and 0.19 mol of oxygen.

(Example 5)
The gas production apparatus produced in Example 2 was installed obliquely with respect to the horizontal plane so that sunlight was irradiated perpendicularly to the translucent substrate 1. After supplying 0.1 M H ₂ SO ₄ electrolyte from the water supply port 18 to fill the electrolyte chamber 15, sunlight was irradiated.
Further, when the amount of gas recovered from the first gas outlet 20 and the second gas outlet 19 was quantified by fluorescence sensor analysis within 2 hours after the start of sunlight irradiation, hydrogen and oxygen were recovered from each. It was confirmed that Further, as shown in Table 1, each gas amount was 0.47 mol of hydrogen and 0.23 mol of oxygen.

(Example 6)
The gas production apparatus produced in Example 3 was installed obliquely with respect to the horizontal plane so that sunlight was irradiated perpendicularly to the translucent substrate 1. After supplying 0.1 M H ₂ SO ₄ electrolytic solution from the water supply port 18 to fill the electrolytic solution chamber, sunlight was irradiated.
Further, when the amount of gas recovered from the first gas outlet 20 and the second gas outlet 19 was quantified by fluorescence sensor analysis within 2 hours after the start of sunlight irradiation, hydrogen and oxygen were recovered from each. It was confirmed that Moreover, those gas amounts were 0.54 mol of hydrogen and 0.26 mol of oxygen as shown in Table 1.

(Comparative Example 1)
In the gas production apparatus according to the first embodiment, the hydrogen generation unit directly supports platinum as a hydrogen generation catalyst on the back surface of the photoelectric conversion unit 2 without stacking the gas conduction unit 21, and the oxygen generation unit is disposed on the insulating unit 11. RuO ₂ which is an oxygen generation catalyst was laminated with a film thickness of 1 μm by the CVD method, and a gas production apparatus as shown in FIG. 24 was produced.
The gas production apparatus produced as described above was installed obliquely with respect to the horizontal plane so that sunlight was irradiated perpendicularly to the translucent substrate 1. After supplying 0.1 M H ₂ SO ₄ electrolyte from the water supply port 18 to fill the electrolyte chamber 15 and irradiating with sunlight, it can be confirmed that gas is generated from the surface of the hydrogen generating part. It was.
Further, when the amount of gas recovered from the first gas outlet 20 and the second gas outlet 19 was quantified by fluorescence sensor analysis within 2 hours after the start of sunlight irradiation, hydrogen and oxygen were recovered from each. It was confirmed that Moreover, as shown in Table 1, those gas amounts were 0.31 mol of hydrogen and 0.14 mol of oxygen.

  As described above, by generating the gas generated from the first gas generation unit 8 and the second gas generation unit 7 whose reaction surfaces face downward through the gas flow path 17 included in the gas conduction unit 21, the hydrogen generation efficiency is recovered. It was shown that it is possible to increase

  The gas production apparatus of the present invention causes the decomposition reaction of water by solar energy and enables production of hydrogen and oxygen that can be used as fuel. By installing this apparatus, not only concentrated large-scale fuel production but also distributed fuel production in factories, homes, etc. becomes possible.

    1: translucent substrate 2: photoelectric conversion unit 4: first electrode 5: second electrode 7: second gas generation unit 8: first gas generation unit 9: first conductive unit 10: second conductive unit 11: insulation Part 13: Partition 14: Top plate 15: Electrolyte chamber 16: Outer box 17: Gas flow path 18: Water supply port 19: Second gas outlet 20: First gas outlet 21: Gas conduction part 22: Third conductive Part 23: Gas production apparatus 25: Electrolyte solution 27: Generated gas 29: Gas branch channel 31: First opening 32: Second opening 33: First edge 34: Second edge

Claims (29)

A photoelectric conversion unit having a light-receiving surface and a back surface; and a first gas generation unit that generates a first gas from the electrolytic solution by using an electromotive force that is electrically connected to the back surface and is received by the photoelectric conversion unit. , A second gas generation unit that generates a second gas from the electrolyte using an electromotive force that is electrically connected to the light receiving surface and received by the photoelectric conversion unit, a gas flow path, and a gas discharge port And
At least one of the first gas generation unit and the second gas generation unit is provided on the back surface of the photoelectric conversion unit,
The gas flow path is provided between at least one of the first gas generation unit and the second gas generation unit and the back surface of the photoelectric conversion unit,
The gas production apparatus characterized in that the gas flow path conducts the first gas or the second gas to the gas discharge port. A first conductive part;
The first gas generation unit and the second gas generation unit are provided on the back surface of the photoelectric conversion unit,
The gas flow path is provided between the first gas generation unit and the back surface and between the second gas generation unit and the back surface, respectively.
The apparatus according to claim 1, wherein the second gas generation unit is electrically connected to the light receiving surface via the first conductive unit. And further comprising an insulating part,
The device according to claim 2, wherein the second gas generation unit is provided on a back surface of the photoelectric conversion unit via the insulating unit.   The device according to claim 3, wherein the first conductive part includes a first electrode in contact with a light receiving surface of the photoelectric conversion part, and a second conductive part in contact with the first electrode and the second gas generation part, respectively. The photoelectric conversion unit has a first contact hole penetrating from the back surface to the light receiving surface,
The apparatus according to claim 4, wherein the second conductive portion is provided in the first contact hole. A translucent substrate;
The said photoelectric conversion part is an apparatus as described in any one of Claims 2-5 provided on the said translucent board | substrate. A gas branch channel;
The gas branch channel is formed by one of the first gas generation unit and the second gas generation unit, and is connected to the gas channel,
The apparatus according to any one of claims 1 to 6, wherein the gas branch channel conducts the first gas or the second gas to the gas channel. The first gas generator or the second gas generator is plural,
The apparatus according to claim 7, wherein the gas branch channel is provided between two adjacent first gas generation units or between two adjacent second gas generation units. The gas branch channel has a first opening and a second opening at both ends,
The first opening is provided on one of the first gas generation part and the second gas generation part on the surface of the gas flow path,
The second opening is provided on a surface opposite to the surface provided with the first opening,
The second opening has a first edge and a second edge having different heights,
The device according to claim 7 or 8, wherein the first edge is an edge of the second opening higher than the second edge, and causes the first gas or the second gas to flow into the gas branch flow path. One of the first gas and the second gas is H _2, the other A device according to any one of claims 1 to 9 which is O _2.   The apparatus according to claim 1, wherein the gas flow path is provided along the back surface of the photoelectric conversion unit. Further comprising an electrolyte chamber,
The at least one of a 1st gas generation part and a 2nd gas generation part is provided between the back surface of the said photoelectric conversion part, and the said electrolyte chamber, and can be immersed in electrolyte solution. The device according to any one of the above.   The apparatus according to any one of claims 1 to 12, wherein the gas flow path is provided so that any one of a first gas and a second gas can flow in by buoyancy. A gas conduction part is further provided between at least one of the first gas generation part and the second gas generation part and the photoelectric conversion part,
The apparatus according to claim 1, wherein the gas conduction unit includes the gas flow path.   The apparatus according to claim 14, wherein the gas conduction part is formed of a porous material.   The apparatus according to claim 15, wherein the gas conducting portion has a hydrophobic surface.   The apparatus according to any one of claims 14 to 16, wherein the gas conduction part is formed of a superhydrophobic porous film. The first gas generation unit and the second gas generation unit are provided on the back surface of the photoelectric conversion unit,
The gas conduction part is provided between the back surface of the photoelectric conversion part and the first gas generation part and the second gas generation part, and has corrosion resistance and liquid shielding properties against the electrolytic solution. The device according to any one of the above.   The apparatus according to claim 18, wherein the gas conduction unit is provided so as to cover the photoelectric conversion unit.   The apparatus according to any one of claims 14 to 19, wherein the gas conduction part has conductivity. The first gas generation unit and the second gas generation unit are provided on the back surface of the photoelectric conversion unit,
The apparatus further includes a third conductive portion that electrically connects the back surface of the photoelectric conversion unit and the first gas generation unit, and the gas conduction unit is provided between the back surface of the photoelectric conversion unit and the first gas generation unit. And having a second contact hole penetrating the gas conduction part,
The device according to any one of claims 14 to 19, wherein the third conductive portion is provided in the second contact hole.   The device according to claim 1, 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. One of the first gas generation unit and the second gas generation unit 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 catalyst for a reaction in which H ₂ is generated from the electrolytic solution and a catalyst for a reaction in which O ₂ is generated from the electrolytic solution. apparatus.   24. The apparatus according to claim 23, wherein at least one of the hydrogen generation part and the oxygen generation part is formed of a porous conductor carrying a catalyst.   The apparatus according to claim 23 or 24, wherein the hydrogen generation unit and the oxygen generation unit have a hydrophilic surface. The first gas generation unit and the second gas generation unit are provided on the back surface of the photoelectric conversion unit,
The photoelectric conversion unit is provided on a translucent substrate,
A top plate facing the translucent substrate on the first gas generation unit and the second gas generation unit;
The apparatus according to any one of claims 1 to 25, wherein an electrolyte chamber is provided between the first gas generation unit and the top plate and between the second gas generation unit and the top plate.   27. The apparatus according to claim 26, further comprising a partition partitioning the electrolyte chamber between the first gas generation unit and the top plate and the electrolyte chamber between the second gas generation unit and the top plate.   28. The apparatus of claim 27, wherein the partition includes an ion exchanger. The gas production apparatus according to any one of claims 26 to 28 is installed such that the light receiving surface 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 incident on the light receiving surface, whereby the first gas and the second gas are respectively supplied from the first gas generation part and the second gas generation part. A gas production method for generating and discharging the first gas and the second gas from the upper part of the gas production apparatus.

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