JPH11222692A - Gas diffuser electrode - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a gas diffuser electrode by which liq. is surely discharged when there is no space between the gas diffuser electrode and ion-exchange membrane, the supply of gas is never hindered, a high electrode performance is maintained, and the current collecting capacity is improved. SOLUTION: A conductive porous body 2 is used as a core. A reaction bed 3, a gas feed bed 4 and a gas passage bed 5 are successively integrated from the surface side to constitute the electrode main body, and a hydrophilic conductive porous body 6 denser than the conductive porous body 2, permeable to an electrolyte and hardly permeable to the gas is disposed in contact with the gas passage bed 5 to supply the liq. to the porous body 6. The porous body 6 is preferably brought into contact with the frame 10 of an electrolytic cell and supplied with power.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrolysis using an ion exchange membrane as a membrane, and a gas diffusion electrode capable of performing electrolysis without any trouble when the gap between the ion exchange membrane and the ion exchange membrane is zero, that is, when the gap is zero. In particular, the present invention relates to a gas diffusion electrode configured to be able to move an electrolytic solution from a reaction layer side to a gas supply layer side.

[0002]

2. Description of the Related Art A conventional gas diffusion electrode usually comprises a reaction layer and a gas supply layer. Since the gas supply layer is formed only of hydrophobic pores, the electrolyte does not leak to the gas chamber side. . When such a gas diffusion electrode is used as a cathode for salt electrolysis, the structure of the electrolytic cell becomes a three-chamber type. That is, in this case, the electrolytic cell includes three chambers: an anode chamber, a catholyte chamber, and an oxygen gas chamber. To solve the problems caused by this complicated structure,
In order to provide a two-chamber electrolytic cell having a simple structure, a liquid-permeable gas diffusion electrode that allows liquid to pass through a gas supply layer, as described in, for example, Japanese Patent Application Laid-Open No. Hei 7-126880, has been proposed. ing.

[0003]

Such a conventional liquid-permeable gas diffusion electrode has a gas supply layer provided with a hydrophilic through-hole having a diameter of 0.1 to 1 mm so that liquid can pass therethrough. However, although this hole is hydrophilic, its outside is hydrophobic, so that the discharge of the liquid is hindered, and the gas supply is hindered by the adhered droplets discharged to the entire surface of the gas supply layer. There were drawbacks. Therefore, Japanese Patent Application Laid-Open
In JP-A-302492, the amount of an electrolytic solution (caustic solution) that descends between the gas diffusion electrode and the ion exchange membrane and reaches the lower portion of the electrolytic layer is increased, and passes through the gas diffusion electrode to the gas chamber side. Since it is desirable to reduce the amount of the reached electrolyte to facilitate gas supply, a groove is formed on the surface of the reaction layer of the gas diffusion electrode, and the electrolyte is allowed to flow down into the groove. ing. Further, in a liquid-permeable gas diffusion electrode, the gas chamber is narrow, so that the gas flowing in the gas chamber is hindered by the electrolyte leaking to the back side of the electrode, and the gas is uniformly supplied to the gas supply layer sufficiently. It is easy for things not to happen.

[0004] Since the liquid-permeable gas diffusion electrode has such a drawback, when it is installed as an oxygen cathode in an ion-exchange membrane-type salt electrolytic cell, it is 2.3 V under electrolysis conditions of 30 A / dm ² and 80 ° C. It is a high cell voltage.
The present invention has been made in view of such a conventional problem, and the liquid is smoothly discharged, the supply of gas is not hindered, and the liquid can be supplied to the gas chamber side. In this way, the adjustment of the electrolyte concentration becomes easy,
An object of the present invention is to provide a long-life gas diffusion electrode capable of maintaining high electrode performance, improving current collection capability, and lowering the electrolytic cell voltage to the limit.

[0005]

Means for Solving the Problems As a result of intensive studies to solve the above-mentioned problems, the present inventor has found that a gas supply layer in contact with a reaction layer does not impede gas permeation and that the reaction layer and the gas supply layer As a result of examining a gas diffusion electrode with a structure that can easily guide the electrolyte that has passed through to the bottom of the gas chamber, the gas inside the gas chamber is made porous, and that part is used as a gas passage to supply gas from there. When the gas is supplied to the layer, gas flow resistance is low, and the gas can be supplied easily. Moreover, the leaked liquid can be sent to the rear of the gas chamber along the surface of the porous body.
It has been found that a conductive porous body is provided which is easier to pass liquid and harder to pass gas in contact with the porous body, and that the concentration of the electrolyte in the reaction layer can be adjusted by supplying the liquid to the conductive porous body. Based on this, the present invention has been completed.

That is, the present invention has solved the above-mentioned problems by the following means. (1) An electrode body in which a conductive porous body is used as a core material, and a reaction layer, a gas supply layer, and a gas passage section layer are continuously and integrally formed from the surface side, and the electrode body is in contact with the gas passage section layer side. It is characterized by being provided with a hydrophilic conductive porous body that is denser than the conductive porous body, easily penetrates the electrolyte solution, and through which gas does not easily pass, and can supply a liquid to the hydrophilic conductive porous body. Gas diffusion electrode. (2) The gas diffusion electrode according to the above (1), wherein a conductive mesh having a spring property is provided between the conductive porous body and the hydrophilic conductive porous body. (3) The gas diffusion electrode according to (1) or (2), wherein power is supplied by bringing a hydrophilic conductive porous body into contact with the electrolytic cell frame. (4) The reaction layer and the gas supply layer are configured such that the electrolyte moves to the gas passage section layer side or the ion exchange membrane side through the reaction layer and the gas supply layer. The gas diffusion electrode according to any one of (1) to (3).

According to the present invention, a so-called porous body is used as a core material for the main part of the gas diffusion electrode, and a reaction layer, a gas supply layer and a gas passage layer are formed in this order from the surface of the core material. In addition, by constituting this porous body with a conductive material, it serves also as a current feeder. The reaction layer,
The electrolyte leaking through the gas supply layer is easy to propagate,
Since the gas easily flows to the end of the gas passage portion layer, it does not accumulate on the back side of the gas supply layer, and does not hinder the gas from reaching the gas supply layer. Furthermore, the present invention provides a conductive porous body that is in contact with the main body part, is denser than the conductive porous body, easily penetrates the electrolyte, and hardly allows gas to pass therethrough. The electrolyte flowing to the end can be easily received therein.

That is, the gas chamber portion is composed of the gas passage layer and the hydrophilic conductive porous body in contact therewith. The gas passage portion layer is made of only the core material made of the conductive porous material. However, since the density of the gas passage portion layer is lower than the density of the hydrophilic conductive porous material, the hydrophilic conductive porous material is easily permeable to liquid. The gas passes more easily than the body, and the gas can be sufficiently supplied to the gas supply layer through the gas. Moreover, since the gas passage layer is made of a porous material,
Moved from the reaction layer and gas supply layer (leaked)
The liquid can be transmitted and flowed, and the leaked liquid can be flowed and transmitted to a hydrophilic conductive porous body that is easily permeable to liquid. When a conductive reticulated body is inserted between the conductive porous body and the hydrophilic conductive porous body, the spring of the gas is used to assemble the ion-exchange membrane with the force of the spring when assembled. Can be adhered well.

The hydrophilic conductive porous body is denser and denser than the above-mentioned gas passage portion layer, so that the inner passage is narrow, thereby making it difficult for gas to flow, but making it easier for liquid to flow. I have. Specifically, it is necessary that the hydrophilic conductive porous body has a smaller pore diameter or pitch than the conductive porous body of the core material. When a gas and a liquid are caused to flow where a porous body having a higher water absorption and a porous body having a lower water absorption exist, the gas and the liquid flow separately. Further, a part of the porous body serving as the gas passage may be made water-repellent with a fluororesin. By supplying an electrolytic solution, specifically a dilute caustic solution or water (in the present specification, the liquid supplied here is collectively referred to as “electrolytic solution”) from the upper portion of the hydrophilic conductive porous material, The caustic soda concentration can be controlled. In addition, by moving the electrolytic solution supplied to the ion exchange membrane side, it is possible to operate even with the three-chamber method.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION The gas diffusion electrode of the present invention can be used as an oxygen cathode, for example, when electrolyzing salt by an ion exchange method. Usually, the ion exchange membrane method electrolysis is performed in an electrolytic cell partitioned into an anode chamber and a cathode chamber by an ion exchange membrane which is a cation exchange membrane, and an aqueous sodium chloride solution is supplied to an anode chamber having an anode of the electrolytic cell. The caustic soda solution is contained in the cathode section having a cathode, but in the case of using a gas diffusion electrode as the cathode, the cathode section is provided between the ion exchange membrane and the gas diffusion electrode. It is composed of a catholyte chamber containing an aqueous solution, a reaction layer, a gas diffusion electrode composed of a gas supply layer, and an oxygen gas chamber, and is a so-called three-chamber type. However, the present invention is of a two-chamber type when salt is electrolyzed.

Next, the gas diffusion electrode of the present invention will be specifically described with reference to the drawings. That is, the gas diffusion electrode 1 of the present invention
A conductive layer 2 as a core material, a reaction layer 3 from the surface side,
An electrode body in which a gas supply layer 4 and a gas passage section layer 5 are continuously and integrally formed; and an electrolyte solution that is denser than the conductive porous body 2 in contact with the gas passage section layer 5 of the electrode body. A gas diffusion electrode characterized in that a hydrophilic conductive porous body 6 that is easy to pass gas through is provided so that an electrolytic solution can be supplied to the hydrophilic conductive porous body 6. As shown in FIG. 1, the reaction layer 3 is provided on the surface side, and
The gas supply layer 4 is provided on the right side 9).
Has a gas passage section layer 5 on the lower side (right side in FIG. 1),
The reaction layer 3 is formed by baking silver fine powder and polytetrafluoroethylene (PTFE) fine powder, for example, and the gas supply layer 4 is formed only by polytetrafluoroethylene fine powder. However, the gas passage layer 5 is formed only of the core material of the conductive porous body 2. Since the gas passage section layer 5 is made of a porous body, the gas flow path is bent, and as a result, the gas flow velocity is increased. From this point, it is preferable that the porous body as the core material is formed so that the gas flow path is bent at least in the gas passage section layer 5 to increase the gas flow velocity.

A hydrophilic and dense conductive porous body 6 made of nickel, for example, is provided in contact with the gas passage section layer 5. The hydrophilic conductive porous body 6 can be adhered to the gas passage section layer 5 by bonding. Note that it is not necessary to provide the hydrophilic conductive porous body 6 in the entire gas chamber, and as long as the conduction from the hydrophilic conductive porous body 6 to the frame 10 is not hindered, one of the hydrophilic conductive porous bodies 6 may be provided. There is no problem if the part is replaced by the coarse conductive porous body 7, and a part in contact with the frame 10 can be replaced by the coarse conductive porous body 7 as shown in FIG. The gas diffusion electrode configured as described above is inserted so that the conductive porous body 6 is in contact with the conductive frame 10 of the cathode chamber frame 9 of the electrolytic cell, and is placed on the reaction layer 3 on the surface side (FIG. 1). On the left side), the ion exchange membrane 11 is disposed. An oxygen gas inlet 12 is provided at the upper part of the cathode chamber frame 9, and a water or caustic soda aqueous solution inlet 13 is provided in contact with the conductive porous body 6 to introduce water or caustic soda aqueous solution, and a lower outlet 14 is provided. Discharge concentrated caustic soda aqueous solution and unreacted gas.

The inside of the gas diffusion electrode is shown in FIG.
As shown in FIG. 3, a metal wire or a metal net 8 reaching the conductive porous body 6 from the reaction layer 3 via the gas supply layer 4 and the gas passage layer 5 is embedded, and the entire wire or the net is formed. This makes it possible to prevent the reaction layer or the like from peeling off due to heat or the like. The thickness of the line or net can be appropriately selected. When the portion of the frame 10 of the cathode chamber frame 9 is a conductive portion, power can be supplied to the conductive porous body 6 and the reaction layer 3 of the conductive porous body 2 therefrom. If the portion of the conductive porous body 6 on the side facing the gas passage layer is difficult to pass oxygen gas, there is no gas flow in the conductive porous body 6 and the portion on the opposite side thereof does not flow. Does not matter at all even if it is constituted by a coarser porous body through which liquid can easily pass. The reaction layer 3 is hydrophilic and easy to pass liquid, and the gas supply layer 4 is filled with a highly hydrophobic PTFE porous body, but the liquid leaks into the gas passage layer 5.

As the metal wire or metal net 8, a net having a fluffy shape, a three-dimensional net, or a foam is used, and a metal having high corrosion resistance is desirable. Silver netting and silver-plated foamed nickel are preferred. In forming the reaction layer and the like, first, a PTFE dispersion is applied to one surface of the conductive porous body 2 of the core material.
A gas supply layer is formed by applying a layer of self-assembled slurry of alcohol with alcohol to form a gas supply layer, on which a mixture of silver microparticles of 1 micron or less and polytetrafluoroethylene (PTFE) dispersion is applied. A self-assembled slurry is applied in a layer to form a reaction layer. When forming the gas supply layer,
It is necessary to form a gas passage layer so that the slurry does not enter the other surface side of the conductive porous body of the core material. The soluble porous material may be filled in from the other surface side of the porous material, and the soluble material may be dissolved and removed after the formation of the reaction layer.

Examples of the conductive porous body include foamed nickel and silver-plated foamed nickel, and silver-plated foamed nickel is preferred because of its high conductivity. To increase the hydrophilicity and liquid mobility of a part of these surfaces, NiCo
Surface treatment such as corrosion-resistant porous coating such as ₂ O ₄ can also be performed. As silver-plated nickel foam, for example, nickel fine powder is attached to urethane foam, dried and fired, the polyurethane portion is burned off, and nickel is sintered to have a pore diameter of 0.5 to 0.6 mm and a porosity. Is 90
% Or more, a foamed nickel body is obtained, and this foamed nickel is plated with silver having a thickness of 5 to 10 μm in order to improve corrosion resistance. By setting the porous state of the urethane foam in various ways, a predetermined silver-plated nickel foam can be obtained.

Further, when urethane foam having only a skeleton is used as the urethane foam, the thickness of the line is 0.1 mm.
It is possible to obtain a nickel-plated foamed nickel that can be said to be a linear or net-like body having a three-dimensional structure, having a high porosity of 95 to 0.10 mm, a hole diameter of 0.5 to 0.6 mm, and a high porosity of 95%. Such "foamed urethane leaving only the skeleton"
Is obtained by, for example, explosion-treating a polyurethane foam to blow off the wall of the foam, and is composed of only the skeleton of the foam, and thus has a three-dimensional network. By using as a base material, a linear or net-like body having a three-dimensional structure acting as a conductor from the reaction layer can be formed. "Polyurethane foam leaving only the skeleton" has high porosity, so it is easy to apply reaction layer slurry, etc., and silver-plated nickel foam obtained from this has high porosity,
It is preferable because the gas passage portion layer has low airflow resistance.

[0017] Thus, the reaction layer raw material gas supply layer material was filled in layers respectively, dried, extracted remove the surfactant, the press to the reaction layer and the gas supply at a pressure of 40 kg / cm ² at room temperature By increasing the density of the layer and heating at about 250 ° C., a gas diffusion electrode can be obtained. The pressure of the room temperature press is desirably 10 to 50 kg / cm ² , and if pressed at a pressure higher than this, the porosity of both the reaction layer and the gas supply layer is reduced, and the electrode performance is reduced. The heat treatment temperature is preferably from 200 ° C. to 310 ° C. If the heating is performed at a temperature higher than the melting point of the fluororesin (327 ° C.), sintering of the fluororesin proceeds particularly in the gas supply layer, and the porosity decreases, As a result, the electrode performance decreases. In forming the gas supply layer, it is not always necessary to perform sintering of the fluororesin, and since the fluororesin fine powder has a property of binding by pressing, these layers can be formed only by pressing operation. Can be formed. The thickness of the reaction layer used in the electrode of the present invention is 0.01 to
1 mm, the thickness of the gas supply layer is preferably 0.01 to 1 mm, the thickness of the gas passage portion layer is preferably 0.1 to 2 mm, and the thickness of the hydrophilic conductive porous body is preferably 0.1 to 3 mm. In the present invention, the cell voltage can be reduced to the limit of 1.9V.

[0018]

The present invention will be described in detail with reference to the following examples. However, the present invention is not limited to only these examples. Throughout the examples, all parts mean parts by weight.

Example 1 A PTFE dispersion D-1 (Daikin Industries, Ltd.) was applied to the surface of a silver-plated porous thin plate in which a nickel foamed member having a thickness of 1.7 mm and a size of 12 × 28 cm was plated with silver having a thickness of 5 μm. (Manufactured by a company) and ethanol was added to 1 part to form a paste. The thickness of this gas supply layer finally becomes 0.5 mm. Silver fine particles (Mitsui Mining & Smelting, Ag-3010, average particle size 0.11 micron)
To 5 parts, 1 part of surfactant Triton and 9 parts of water are added and dispersed by an ultrasonic dispersing machine. To this, 1 part of PTFE dispersion D-1 (manufactured by Daikin Industries, Ltd.) is added, and the mixture is stirred and mixed. Then, 2 parts of ethanol is added, and the mixture is self-organized by stirring. The precipitate is filtered through a filter paper having a pore size of 1 μm, and the slurry is applied on the gas supply layer of the silver-plated foamed nickel sheet and pressed at a pressure of 10 kg / cm ² to form a reaction layer. The thickness of this reaction layer is finally 0.15 mm.

This was dried at 80 ° C. for 3 hours, and the surfactant was removed with an extractor using ethanol.
After drying for a period of time, a silicone resin sheet is overlaid on the gas supply layer side, pressed at room temperature and 40 kg / cm ² for 60 seconds, then heat-treated at 250 ° C. without pressure for 10 minutes, and subsequently cooled to form an electrode. Got the body. At this time, the used amount of the silver fine particles was 430 g / m ² . As a result, nothing is applied to one surface side of the silver-plated nickel foam sheet, so that portion becomes a gas passage portion layer. The gas diffusion electrode of the present invention was obtained by bonding a hydrophilic dense nickel porous body having a thickness of 2 mm in contact with the gas passage layer of the electrode body. This electrode was fitted into the cathode chamber frame shown in FIG. 1 and the ion exchange membrane was brought into close contact with the electrode chamber to assemble a salt electrolysis cell with no gap between the electrode and the ion exchange membrane and operated continuously. As a result, an electrolytic cell voltage of 1.98 V was obtained with a current density of 30 A / dm ² , a temperature of 90 ° C., a catholyte concentration of 32% NaOH, and an oxygen supply of twice the theoretical value. 50
It can be operated without voltage fluctuation for a day and is continuing. It was found that even if the electrolyte solution permeated through the ion exchange membrane was caused to leak all the gas diffusion electrode, there was almost no effect on the electrode performance.

Example 2 PTFE dispersion D-1 (manufactured by Daikin Industries, Ltd.)
One part was added with ethanol to form a paste, and then 50 pp
i, a gas supply layer is formed by pushing into a silver-plated nickel foam body having a thickness of 1.7 mm and a size of 10 × 60 cm square. Immediately from above, 2 parts of PTFE dispersion D-1 (manufactured by Daikin Industries, Ltd.) were added to 5 parts of silver fine particles (Ag-3030, manufactured by Mitsui Mining & Smelting, average particle size: 0.3 micron) and mixed with stirring. Thereafter, 1 part of ethanol was added, and a silver-PTFE paste self-assembled by stirring was printed thereon, pressed at a pressure of 10 kg / cm ² , and pressed into the inside of a silver-plated foamed nickel body to form a reaction layer. To form Thus, a gas supply layer and a reaction layer are formed.

This was dried at 80 ° C. for 3 hours, and the surfactant was removed with an extractor using ethanol.
After drying for a period of time, a silicone resin sheet is overlaid on the gas supply layer side, pressed at room temperature and 40 kg / cm ² for 60 seconds, then heat-treated at 250 ° C. without pressure for 10 minutes, and then cooled. Thus, a gas diffusion electrode 18 having the gas supply layer 15, the reaction layer 16, and the gas passage layer 17 of FIG. 2 was obtained.
At this time, the used amount of the silver fine particles was 480 g / m ² .

As shown in FIG. 2, the frame 21 has a hydrophilic porous body of 50 ppi, a thickness of 1.7 mm, and a size of 1.
A silver-plated foamed nickel body 22 of 0 × 60 cm square is joined, and a silver-plated 1 mm-thick resilient net (referred to as “spring net”) 23 is overlaid thereon.
8. The ion exchange membrane 19 and the anode 20 were set. The gas diffusion electrode 18 is held between the fixed anode 20 and the frame 21 by a spring mesh 23 having a thickness of 1 mm.
8 and the foamed nickel body 22 which is a hydrophilic porous body are electrically contacted, and electricity can be supplied. This gas diffusion electrode 1
There is a zero gap between 8 and the ion exchange membrane 19. The salt electrolyzer was operated. As a result, 30 A / dm ² ,
Under the electrolysis conditions of 90 ° C. and 32% NaOH, the theoretical value of 1.8 was obtained.
With twice the oxygen supply, an electrolytic cell voltage of 2.05 V was obtained.

[0024]

According to the gas diffusion electrode of the present invention, since the reaction layer, the gas supply layer and the gas passage layer are formed on the integral conductive core material, the flow resistance of the gas in the gas passage layer is reduced. And the gas is sufficiently and uniformly supplied to the gas supply layer. Furthermore, since the conductive porous body is provided in close contact with the hydrophilic conductive porous body, the electrolyte can flow down into the hydrophilic conductive porous body.
The leaked caustic soda solution is allowed to flow there, and if necessary, the supplied water is allowed to flow there to adjust the caustic soda concentration in the reaction layer to obtain a caustic soda solution having a predetermined concentration. Power can also be supplied directly from the cathode chamber frame of the electrolytic cell to the reaction layer of the integral conductive porous body via the hydrophilic conductive porous body. Further, the gas diffusion electrode has a high strength because the two conductive porous bodies are combined. If a wire or a net is provided inside the conductive porous body and bonded to each other, the structure can be further strengthened.
Further, when a spring network is provided between the two conductive porous bodies, the surface of the gas diffusion electrode can be brought into close contact with the ion exchange membrane.

[Brief description of the drawings]

FIG. 1 is an explanatory sectional view showing an example of a gas diffusion electrode of the present invention.

FIG. 2 is an explanatory sectional view showing another example of the gas diffusion electrode of the present invention.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 gas diffusion electrode 2 conductive porous material 3 reaction layer 4 gas supply layer 5 gas passage layer 6 hydrophilic conductive porous material 7 coarse conductive porous material 8 metal wire 9 cathode chamber frame 10 frame 11 ion exchange membrane 12 oxygen Gas inlet 13 Water or caustic soda aqueous solution inlet 14 Outlet 15 Reaction layer 16 Gas supply layer 17 Gas passage section layer 18 Gas diffusion electrode 19 Ion exchange membrane 20 Anode 21 Frame 22 Silver-plated nickel foam body 23 Spring net

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[Procedure amendment]

[Submission date] February 22, 1999

[Procedure amendment 1]

[Document name to be amended] Statement

[Correction target item name] Claim 4

[Correction method] Change

[Correction contents]

[Procedure amendment 2]

[Document name to be amended] Statement

[Correction target item name] 0003

[Correction method] Change

[Correction contents]

[0003]

Such a conventional liquid-permeable gas diffusion electrode has a gas supply layer provided with a hydrophilic through-hole having a diameter of 0.1 to 1 mm so that liquid can pass therethrough. However, although this hole is hydrophilic, its outside is hydrophobic, so that the discharge of the liquid is hindered, and the gas supply is hindered by the adhered droplets discharged to the entire surface of the gas supply layer. There were drawbacks. Therefore, Japanese Patent Application Laid-Open
In JP-A-302492, the amount of an electrolytic solution (caustic solution) that descends between the gas diffusion electrode and the ion exchange membrane and reaches the lower part of the electrolytic cell is increased, and passes through the gas diffusion electrode to the gas chamber side. Since it is desirable to reduce the amount of the reached electrolyte to facilitate gas supply, a groove is formed on the surface of the reaction layer of the gas diffusion electrode, and the electrolyte is allowed to flow down into the groove. ing. Further, in a liquid-permeable gas diffusion electrode, the gas chamber is narrow, so that the gas flowing in the gas chamber is hindered by the electrolyte leaking to the back side of the electrode, and the gas is uniformly supplied to the gas supply layer sufficiently. It is easy for things not to happen.

[Procedure amendment 3]

[Document name to be amended] Statement

[Correction target item name] 0006

[Correction method] Change

[Correction contents]

That is, the present invention has solved the above-mentioned problems by the following means. (1) An electrode body in which a conductive porous body is used as a core material, and a reaction layer, a gas supply layer, and a gas passage section layer are continuously and integrally formed from the surface side, and the electrode body is in contact with the gas passage section layer side. It is characterized by being provided with a hydrophilic conductive porous body that is denser than the conductive porous body, easily penetrates the electrolyte solution, and through which gas does not easily pass, and can supply a liquid to the hydrophilic conductive porous body. Gas diffusion electrode. (2) The gas diffusion electrode according to the above (1), wherein a conductive mesh having a spring property is provided between the conductive porous body and the hydrophilic conductive porous body. (3) The gas diffusion electrode according to (1) or (2), wherein power is supplied by bringing a hydrophilic conductive porous body into contact with the electrolytic cell frame. (4) the reaction layer and the gas supply layer, wherein the electrolyte is configured to be able to move into the reaction layer and the gas passage layer side or the surface side through a gas supply layer The gas diffusion electrode according to any one of (1) to (3).

[Procedure amendment 4]

[Document name to be amended] Statement

[Correction target item name] 0011

[Correction method] Change

[Correction contents]

Next, the gas diffusion electrode of the present invention will be specifically described with reference to the drawings. That is, the gas diffusion electrode 1 of the present invention
A conductive layer 2 as a core material, a reaction layer 3 from the surface side,
An electrode body in which a gas supply layer 4 and a gas passage section layer 5 are continuously and integrally formed; and an electrolyte solution that is denser than the conductive porous body 2 in contact with the gas passage section layer 5 of the electrode body. A gas diffusion electrode characterized in that a hydrophilic conductive porous body 6 that is easy to pass gas through is provided so that an electrolytic solution can be supplied to the hydrophilic conductive porous body 6. As shown in FIG. 1, the reaction layer 3 is provided on the surface side, and
In a gas supply layer 4 on the right side), it has a gas passage layer 5 on the gas below the supply layer 4 (right side in FIG. 1), the reaction layer 3 is, for example, silver fine powder and polytetrafluoroethylene The (PTFE) fine powder is formed by firing, and the gas supply layer 4 is formed only of the polytetrafluoroethylene fine powder. However, the gas passage layer 5 is formed only of the core material of the conductive porous body 2. In the gas passage section layer 5,
Since it is made of a porous material, the gas flow path is bent, and as a result, the gas flow velocity is increased. From this point, it is preferable that the porous body as the core material is formed so that the gas flow path is bent at least in the gas passage section layer 5 to increase the gas flow velocity.

[Procedure amendment 5]

[Document name to be amended] Drawing

[Correction target item name] Fig. 1

[Correction method] Change

[Correction contents]

FIG.

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Choichi Furiya 2-14 Nakamuracho, Kofu City, Yamanashi Prefecture

Claims (4)

[Claims] An electrode body having a conductive porous body as a core material, a reaction layer, a gas supply layer, and a gas passage section layer formed continuously and integrally from the surface side; and a gas passage section layer side of the electrode body. It is provided that a hydrophilic conductive porous body that is in contact with the conductive porous body, is denser than the conductive porous body, easily penetrates the electrolyte, and hardly allows gas to pass therethrough, so that a liquid can be supplied to the hydrophilic conductive porous body. Characterized gas diffusion electrode. 2. The gas diffusion electrode according to claim 1, wherein a conductive mesh having spring properties is provided between the conductive porous body and the hydrophilic conductive porous body. 3. The gas diffusion electrode according to claim 1, wherein power is supplied by bringing a hydrophilic conductive porous body into contact with the electrolytic cell frame. 4. The reaction layer and the gas supply layer, wherein the electrolyte is moved to the gas passage layer side or the ion exchange membrane side through the reaction layer and the gas supply layer. The gas diffusion electrode according to any one of claims 1 to 3.