JP2016221448A - Hydrogen peroxide decomposition catalyst and fuel battery - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a hydrogen peroxide decomposition catalyst capable of attaining low cost while obtaining high hydrogen peroxide decomposition activity, and a fuel battery capable of preventing deterioration caused by by-produced hydrogen peroxide while suppressing the increase of cost.SOLUTION: Provided is a fuel battery 1 including: a membrane electrode joined body 2 having an electrolytic membrane 7, an anode 8 formed on either side of the electrolytic membrane 7; and a cathode 9 formed on the other side of the electrolytic membrane 7; an anode side separator 5 arranged on either side of the membrane electrode joined body 2; and a cathode side separator 6 arranged at the other side of the membrane electrode joined body 2, the space between the cathode 9 and the cathode side separator 6, a porous layer 11 (hydrogen peroxide decomposition catalyst layer) including the sintered compact of a raw material complex including at least either an Fe complex in which ligands are oriented into iron or an Mn complex in which ligands are oriented into manganese is arranged.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a hydrogen peroxide decomposition catalyst and a fuel cell mounted on a vehicle or the like.

  Conventionally, fuel cells using gaseous fuel such as hydrogen gas or liquid fuel such as methanol, dimethyl ether or hydrazine are known as fuel cells mounted on vehicles.

  Such a fuel cell is configured as a stack structure in which a plurality of unit cells each including an electrolyte layer and an anode and a cathode stacked on both sides of the electrolyte layer are stacked.

  More specifically, for example, an electrolyte layer made of an anion exchange membrane, and a fuel side electrode and an oxygen side electrode that are arranged to face each other with the electrolyte layer interposed therebetween are provided. A fuel cell is proposed in which oxygen is supplied to the oxygen side electrode via an oxygen side flow path (see, for example, Patent Document 1).

  In such a fuel cell, an oxygen reduction reaction in which hydrogen peroxide is by-produced may occur in the oxygen reduction reaction at the oxygen side electrode. In this case, the by-produced hydrogen peroxide may cause deterioration of the fuel cell member.

  As a catalyst for decomposing hydrogen peroxide, for example, a platinum catalyst is known (for example, see Non-Patent Document 1).

JP 2010-225471 A

Electrochemistry Communications 1 (1999) 614-617

  However, the platinum catalyst as shown in Non-Patent Document 1 is a noble metal and is expensive. Therefore, if a platinum catalyst is used to decompose the by-produced hydrogen peroxide, it is difficult to reduce the cost of the fuel cell.

  Accordingly, an object of the present invention is to provide a hydrogen peroxide decomposition catalyst capable of achieving cost reduction while being able to obtain hydrogen peroxide decomposition activity equivalent to that of a platinum catalyst, and a secondary An object of the present invention is to provide a fuel cell capable of preventing deterioration due to the produced hydrogen peroxide.

The present invention
[1] It comprises a sintered body of a raw material complex containing at least one of an Fe complex in which a ligand is coordinated to iron and an Mn complex in which a ligand is coordinated to manganese. Hydrogen oxide cracking catalyst,
[2] A membrane electrode assembly having an electrolyte membrane, an anode formed on one surface of the electrolyte membrane, and a cathode formed on the other surface of the electrolyte membrane, and disposed on one side of the membrane electrode assembly An anode side separator, a cathode side separator disposed on the other side of the membrane electrode assembly, and a porous layer disposed between the cathode and the cathode side separator, the porous layer comprising: A fuel cell comprising a sintered body of a raw material complex containing at least one of an Fe complex in which a ligand is coordinated to iron and an Mn complex in which a ligand is coordinated to manganese .

  According to the hydrogen peroxide decomposition catalyst of the present invention, an Fe complex in which a ligand is coordinated with iron and a Mn complex in which a ligand is coordinated with manganese are used without using a noble metal such as platinum. It includes a fired body of a raw material complex containing either one.

  Therefore, it is possible to reduce the cost of the hydrogen peroxide decomposition catalyst while obtaining the hydrogen peroxide decomposition activity equivalent to that of the platinum catalyst.

  Further, according to the fuel cell of the present invention, a fired body of a raw material complex containing at least one of an Fe complex in which a ligand is coordinated to iron and an Mn complex in which a ligand is coordinated to manganese. A porous layer including hydrogen peroxide decomposition catalyst layer is disposed between the cathode and the cathode-side separator.

  Therefore, hydrogen peroxide produced as a by-product in the cathode can be efficiently decomposed in the porous layer before acting on the cathode-side separator.

  As a result, compared with the case where a noble metal such as platinum is used as a hydrogen peroxide decomposition catalyst, it is possible to prevent deterioration due to by-produced hydrogen peroxide while suppressing an increase in cost.

FIG. 1 is a schematic configuration diagram showing an embodiment of a fuel cell of the present invention. FIG. 2 is an exploded perspective view of the fuel cell shown in FIG. FIG. 3 is a graph showing the hydrogen peroxide decomposition activity of Examples 1 and 2 and Comparative Examples 1 and 2. FIG. 4 is a graph showing open circuit voltages of Example 3 and Comparative Example 3. FIG. 4 is a graph showing the amount of hydrogen peroxide generated in Example 3 and Comparative Example 3.

1. Fuel Cell The fuel cell 1 is normally configured as a stack structure in which a plurality of fuel cells S are stacked. In FIG. 1, only one fuel cell S is shown for easy illustration.

  The fuel cell 1 is a direct liquid fuel type fuel cell to which a liquid fuel containing a fuel component and water is directly supplied, and is configured as an anion exchange type fuel cell.

  Examples of the fuel component include hydrogen-containing liquid fuels containing hydrogen atoms in the molecule, and specific examples include alcohols such as methanol, ethers having an alkyl group such as dimethyl ether, and hydrazines. Preferably, alcohols and hydrazines are used, and more preferably, hydrazines are used.

  In addition, for example, an alkali metal hydroxide such as potassium hydroxide is added to the liquid fuel at an appropriate ratio.

  As shown in FIGS. 1 and 2, the fuel battery cell S includes a membrane electrode assembly 2, a fuel diffusion sheet 3, an air diffusion sheet 4, an anode side separator 5, and a cathode side separator 6.

  The membrane electrode assembly 2 includes an electrolyte membrane 7, an anode 8, and a cathode 9.

  The electrolyte membrane 7 is formed of an anion exchange type solid polymer electrolyte membrane.

  The anode 8 is laminated as a thin layer on the surface of one side in the thickness direction of the electrolyte membrane 7. The anode 8 contains, for example, a catalyst carrier that supports a fuel oxidation catalyst. The anode 8 can also be formed directly from the fuel oxidation catalyst without using a catalyst carrier.

  The fuel oxidation catalyst is not particularly limited, and examples thereof include platinum group elements (ruthenium (Ru), rhodium (Rh), palladium (Pd), osmium (Os), iridium (Ir), platinum (Pt)), and iron group. Periodic table 8-10 (VIII) group elements such as elements (iron (Fe), cobalt (Co), nickel (Ni)), for example, copper (Cu), silver (Ag), gold (Au), etc. Examples include Group 11 (IB) elements of the periodic table. Among these, Preferably, nickel, cobalt, and platinum are mentioned, More preferably, nickel is mentioned. These may be used alone or in combination of two or more.

  Examples of the catalyst carrier used for the anode 8 include carbon particles.

  In order to form the anode 8, for example, ink obtained by dispersing a fuel oxidation catalyst in a solvent together with a binder is applied to one surface of the electrolyte membrane 7 and dried. When the anode 8 is directly formed on one surface of the electrolyte membrane 7 as described above, the binder is selected in consideration of the affinity with the electrolyte membrane 7. For example, when the electrolyte membrane 7 is an anion exchange type solid polymer electrolyte membrane, an anion exchange resin can be used as a binder.

In the anode 8, the loading amount of the fuel oxidation catalyst is, for example, 0.05 mg / cm ² or more, preferably 0.1 mg / cm ² or more, for example, 10 mg / cm ² or less, preferably 5 mg / cm ^2. It is as follows.

  The cathode 9 is laminated as a thin layer on the opposite side of the anode 8 with respect to the electrolyte membrane 7, that is, on the other surface in the thickness direction of the electrolyte membrane 7. The cathode 9 contains an oxygen reduction catalyst.

  Examples of the oxygen reduction catalyst include a material in which a transition metal is supported on a composite composed of a conductive polymer and carbon (hereinafter, this composite is referred to as “carbon composite”).

  Examples of the transition metal include scandium (Sc), titanium (Ti), vanadium (V), chromium (Cr), manganese (Mn), iron (Fe), cobalt (Co), nickel (Ni), copper (Cu ), Yttrium (Y), zirconium (Zr), niobium (Nb), molybdenum (Mo), technetium (Tc), ruthenium (Ru), rhodium (Rh), palladium (Pd), silver (Ag), lanthanum (La) ), Hafnium (Hf), tantalum (Ta), tungsten (W), rhenium (Re), osmium (Os), iridium (Ir), platinum (Pt), gold (Au), and the like. These transition metals can be used alone or in combination of two or more.

  Examples of the conductive polymer include polyaniline, polypyrrole, polythiophene, polyacetylene, polyvinylcarbazole, polytriphenylamine, polypyridine, polypyrimidine, polyquinoxaline, polyphenylquinoxaline, polyisothianaphthene, polypyridinediyl, polythienylene, polyparaylene. Examples include phenylene, polyflurane, polyacene, polyfuran, polyazulene, polyindole, and polydiaminoanthraquinone. These conductive polymers can be used alone or in combination of two or more.

  In addition, examples of the oxygen reduction catalyst include those that overlap with a hydrogen peroxide reduction catalyst described later, and examples thereof include a fired product of a transition metal complex in which a ligand is coordinated to a transition metal.

  As a transition metal, the same transition metal as the transition metal used for the above-mentioned carbon composite is mentioned, for example. The transition metal is preferably iron. That is, the oxygen reduction catalyst is preferably a fired body of an Fe complex in which a ligand is coordinated to iron.

  Examples of the ligand that coordinates to the transition metal include phenanthroline (eg, 1,10-phenanthroline), sarcomin, nicarbazine, pyrrole, porphyrin, tetramethoxyphenylporphyrin, dibenzotetraazaannulene, phthalocyanine, choline, chlorin, or And derivatives thereof.

  Preferable examples of the ligand include phenanthroline, salcomine, nicarbazine, and derivatives thereof, and more preferable examples include phenanthroline and nicarbazine.

  The oxygen reduction catalyst can be obtained, for example, by the same method as the hydrogen peroxide reduction catalyst described later.

  In addition to the oxygen reduction catalyst, the cathode 9 can also contain, for example, carbon black such as oil furnace black, acetylene black, ketjen black and channel black, for example, carbon particles such as graphite and carbon fiber.

  The cathode 9 can be formed, for example, in the same manner as the formation of the anode 8 described above.

In the cathode 9, the supported amount of the oxygen reduction catalyst is, for example, 0.05 mg / cm ² or more, preferably 0.1 mg / cm ² or more, for example, 10 mg / cm ² or less, preferably 5 mg / cm ^2. It is as follows.

  The fuel diffusion sheet 3 is laminated on one side in the thickness direction of the membrane electrode assembly 2 so as to contact one side in the thickness direction of the anode 8. The fuel diffusion sheet 3 has pores for allowing liquid fuel to pass therethrough.

  Examples of the material for the fuel diffusion sheet 3 include carbon paper, carbon cloth, carbon fiber nonwoven fabric, and preferably carbon cloth. Further, the fuel diffusion sheet 3 may be treated with fluorine as necessary.

  The air diffusion sheet 4 is laminated on the other side in the thickness direction of the membrane electrode assembly 2. The air diffusion sheet 4 has pores for allowing air to pass therethrough. The air diffusion sheet 4 includes a base material 10 and a porous layer 11.

  Examples of the material of the base material 10 include the same material as that of the fuel diffusion sheet 3 described above.

  The porous layer 11 is formed on one surface in the thickness direction of the substrate 10. The porous layer 11 is in contact with the other surface in the thickness direction of the cathode 9. The porous layer 11 contains a hydrogen peroxide decomposition catalyst.

  The hydrogen peroxide decomposition catalyst includes a fired body of a raw material complex containing at least one of an Fe complex in which a ligand is coordinated with iron and an Mn complex in which a ligand is coordinated with manganese.

  The hydrogen peroxide decomposition catalyst is preferably a fired body of an Fe complex in which a ligand is coordinated to iron, a fired body of an Mn complex in which a ligand is coordinated to manganese, or a ligand is coordinated to iron A sintered body of a mixture of an Fe complex and a Mn complex in which a ligand is coordinated to manganese, and more preferably a sintered body of an Fe complex in which a ligand is coordinated to iron.

  As a ligand, the same ligand as the ligand used for an above-mentioned oxygen reduction catalyst is mentioned, for example.

  Preferable examples of the ligand include phenanthroline, salcomine, nicarbazine, and derivatives thereof, and more preferable examples include phenanthroline and nicarbazine.

  In order to obtain a fired body of a raw material complex, first, a raw material complex is prepared.

  The raw material complex is not particularly limited, and a known method can be employed.

  For example, an iron salt (for example, an inorganic salt such as sulfate, nitrate, chloride or phosphate, for example, an organic acid salt such as acetate or oxalate) and a ligand, for example, water The Fe complex can be produced by mixing in a known solvent such as alcohol, aliphatic hydrocarbon, aromatic hydrocarbon, halogenated hydrocarbon, or nitrile.

  Further, a Mn complex can be produced by the same method as that for the Fe complex.

  Next, in order to obtain a hydrogen peroxide decomposition catalyst, the raw material complex is calcined.

  In order to fire the raw material complex, for example, the raw material complex is heated in an atmosphere of an inert gas (for example, nitrogen gas, argon gas, etc.) or a reducing gas (for example, a mixed gas of nitrogen gas and hydrogen gas).

  The flow rate of the inert gas at the time of baking is, for example, 10 mL / min or more, preferably 15 mL / min or more, for example, 40 mL / min or less per 1 g of the raw material complex.

  The firing temperature is, for example, 400 ° C. or higher, preferably 600 ° C. or higher, and for example, 1000 ° C. or lower. The firing time is, for example, 1 hour or longer, and for example, 10 hours or shorter, preferably 5 hours or shorter.

  Thereby, the sintered body of a raw material complex can be obtained.

  In order to form the porous layer 11, for example, an ink obtained by dispersing a hydrogen peroxide decomposition catalyst in a solvent together with a binder is applied to one side in the thickness direction of the substrate 10, dried, and then heat-treated. . Examples of the binder include fluororesins such as polytetrafluoroethylene and tetrafluoroethylene / hexafluoropropylene copolymer.

  The heat treatment is performed, for example, at 80 to 120 ° C. for 30 to 90 minutes, then at 200 to 300 ° C. for 30 to 90 minutes, then at 300 to 400 ° C. for 30 to 90 minutes, and an inert gas (for example, nitrogen) Perform in an atmosphere. The pores can be formed in the porous layer 11 by drying and heat-treating the ink applied to the substrate 10.

  The anode-side separator 5 is disposed opposite to one side in the thickness direction of the membrane electrode assembly 2 so as to contact one side in the thickness direction of the fuel diffusion sheet 3. The anode-side separator 5 is made of a gas impermeable conductive material. The anode side separator 5 has a fuel flow path 12.

  The fuel flow path 12 is formed on the other surface in the thickness direction of the anode-side separator 5. The fuel flow path 12 is a concave groove that is recessed from the other side in the thickness direction of the anode-side separator 5 to one side in the thickness direction, and is formed in a folded shape extending in the vertical direction while being folded back in the width direction. The fuel flow path 12 faces the fuel diffusion sheet 3.

  The cathode-side separator 6 is disposed opposite to the other side in the thickness direction of the membrane electrode assembly 2 so as to contact the other side in the thickness direction of the base material 10 of the air diffusion sheet 4. That is, the porous layer 11 is interposed between the cathode side separator 6 and the cathode 9. The cathode side separator 6 is made of a gas impermeable conductive material. The cathode side separator 6 has an air flow path 13.

  The air flow path 13 is formed on one surface of the cathode separator 6 in the thickness direction. The air flow path 13 is a concave groove that is recessed from one surface in the thickness direction of the cathode-side separator 6 to the other in the thickness direction, and is formed in a folded shape extending in the vertical direction while being folded back in the width direction. The air flow path 13 faces the base material 10 of the air diffusion sheet 4.

In the case of a stack structure in which a plurality of fuel cells S are stacked, an air flow path 13 facing the cathode 9 of the adjacent membrane electrode assembly 2 is provided on one surface in the thickness direction of the anode separator 5. Is formed. A fuel flow path 12 facing the anode 8 of the adjacent membrane electrode assembly 2 is formed on the other surface in the thickness direction of the cathode side separator 6.
2. Next, power generation in the fuel cell 1 will be described.

  As shown in FIG. 1, when liquid fuel is supplied to the fuel flow path 12 of the fuel cell 1, the liquid fuel supplied to the fuel flow path 12 passes through the fuel flow path 12 while contacting the fuel diffusion sheet 3. Flow from bottom to top. At this time, the liquid fuel flowing in the fuel flow path 12 passes through the pores of the fuel diffusion sheet 3 and is supplied to the anode 8.

  A part of the liquid fuel supplied to the anode 8 permeates the electrolyte membrane 7 and leaks to the cathode 9 (cross leak). Thereby, water contained in the liquid fuel is supplied to the cathode 9.

  Air from the outside is supplied to the air flow path 13 of the fuel cell 1.

  The air supplied to the air flow path 13 flows in the air flow path 13 from the upper side to the lower side. At this time, the air flowing in the air flow path 13 passes through the pores of the base material 10 of the air diffusion sheet 4 and the porous layer 11 and is supplied to the cathode 9.

Thereby, in the fuel cell 1, when the fuel component is hydrazine, an electrochemical reaction represented by the following reaction formulas (1) to (3) occurs, and power generation is performed.
(1) N ₂ H ₄ + 4OH ⁻ → N ₂ + 4H ₂ O + 4e ⁻ (reaction at anode 8)
(2) O ₂ + 2H ₂ O + 4e ⁻ → 4OH ⁻ (reaction at cathode 9)
(3) N ₂ H ₄ + O ₂ → N ₂ + 2H ₂ O (reaction in the entire fuel cell 1)
Further, when the fuel component is methanol, an electrochemical reaction represented by the following reaction formulas (4) to (6) occurs, and power generation is performed.
(4) CH ₃ OH + 6OH ⁻ → CO ₂ + 5H ₂ O + 6e ⁻ (reaction at anode 8)
(5) O ₂ + 2H ₂ O + 4e ⁻ → 4OH ⁻ (reaction at cathode 9)
(6) CH ₃ OH + 3 / 2O ₂ → CO ₂ + 2H ₂ O (reaction in the entire fuel cell 1)
By these reactions, fuel components (N ₂ H ₄ or CH ₃ OH) are consumed, and water (H ₂ O) and gas (N ₂ or CO ₂ ) are generated, and electromotive force (e ⁻ ) is generated. To do.
3. According to the hydrogen peroxide decomposition catalyst of the present invention, an Fe complex in which a ligand is coordinated to iron and a Mn complex in which a ligand is coordinated to manganese without using a noble metal such as platinum. A fired body of a raw material complex containing at least one of the above.

  Therefore, as shown in the examples described later, it is possible to reduce the cost of the hydrogen peroxide decomposition catalyst while obtaining the equivalent hydrogen peroxide decomposition activity of the platinum catalyst.

In the power generation described above, at the cathode 9, as well as the oxygen reduction reactions shown in (2) and (5) above, as a side reaction, as shown in the following (7), an oxygen reduction reaction accompanied by the generation of hydrogen peroxide occurs. May happen.
_{(7) O 2 + H 2} O + 2e - → HO 2 - + OH - ( secondary reaction at the cathode 9)
Here, the side reaction shown in the above (7) tends to be selectively promoted by carbon.

  Further, when the liquid fuel contains an alkaline electrolyte such as potassium hydroxide, when the liquid fuel leaks into the cathode 9 or the porous layer 11 of the air diffusion sheet 4 due to cross leak, it is shown in the above (7). Side reactions tend to be further promoted.

  Therefore, if the cathode 9 or the porous layer 11 contains carbon, the side reaction shown in the above (7) is promoted, and the hydrogen peroxide produced as a by-product acts on peripheral members such as the cathode-side separator 6. Then, there is a risk of deteriorating surrounding members.

  However, according to the fuel cell 1 of the present invention, a fired body of a raw material complex containing at least one of an Fe complex in which a ligand is coordinated to iron and an Mn complex in which a ligand is coordinated to manganese A porous layer 11 containing hydrogen (that is, a hydrogen peroxide decomposition catalyst layer) is disposed between the cathode 9 and the cathode-side separator 6.

  Therefore, the hydrogen peroxide produced as a by-product in the cathode 9 can be efficiently decomposed in the porous layer 11 before acting on peripheral members such as the cathode-side separator 6.

  As a result, compared with the case where a noble metal such as platinum is used as a hydrogen peroxide decomposition catalyst, the cost of the fuel cell 1 is suppressed, and the member such as the cathode side separator 6 is formed by the by-produced hydrogen peroxide. Deterioration can be prevented.

  In the above-described embodiment, hydrogen gas or the like can be used instead of the liquid fuel.

  Next, although this invention is demonstrated based on an Example and a comparative example, this invention is not limited by the following Example. “Part” and “%” are based on mass unless otherwise specified. In addition, specific numerical values such as a blending ratio (content ratio), physical property values, and parameters used in the following description are described in the above-mentioned “Mode for Carrying Out the Invention”, and a blending ratio corresponding to them ( Substituting the upper limit value (numerical value defined as “less than” or “less than”) or the lower limit value (number defined as “greater than” or “exceeded”) such as content ratio), physical property values, parameters, etc. be able to.

1. Evaluation of hydrogen peroxide decomposition activity <Example 1>
To 5 mg of the Fe phenanthroline catalyst, 20 ml of a 25 ppm aqueous hydrogen peroxide solution was added and stirred at 25 ° C.

Changes in the hydrogen peroxide concentration over time were measured with a hydrogen peroxide test paper (Hishoe Chemical Co., Ltd.). The results are shown in FIG.
<Example 2>
A change in the hydrogen peroxide concentration with the passage of time was measured in the same manner as in Example 1 except that a Fe nicarbazine catalyst (NPC-2000, manufactured by Pajarito) was used instead of the Fe phenanthroline catalyst. The results are shown in FIG.
<Comparative Example 1>
The change in the hydrogen peroxide concentration over time was measured in the same manner as in Example 1 except that a Pt-supported carbon catalyst (TEC10E60E, manufactured by Tanaka Kikinzoku) was used instead of the Fe-phenanthroline-based catalyst. The results are shown in FIG.
<Comparative example 2>
The change in the hydrogen peroxide concentration over time was measured in the same manner as in Example 1 except that ketjen black was used instead of the Fe-phenanthroline-based catalyst. The results are shown in FIG.

2. Performance Evaluation of Fuel Cell (1) Fabrication of Fuel Cell <Example 3>
(1-1) Formation of Anode 0.15 g of Ni-supported carbon catalyst (manufactured by Cataler) and 1.5 g of a solvent (a mixture of tetrahydrofuran and 1-propyl alcohol at a mass ratio of 1: 1) were subjected to ultrasonic treatment. And dispersed at 25 ° C. for 10 minutes.

  Next, 1.0 g of a 2 mass% anion exchange resin solution (solvent: a mixture of tetrahydrofuran and 1-propyl alcohol at a mass ratio of 1: 1) was added to the obtained mixture.

  Subsequently, the ink for anodes was prepared by disperse | distributing with an ultrasonic wave at 25 degreeC for 3 minute (s).

  The obtained anode ink was applied by a spray method so as to cover one surface of the anion exchange membrane (electrolyte membrane).

  Then, the anode was formed by drying at 25 degreeC.

The amount of catalyst supported on the anode was 2.6 mg / cm ² .
(1-2) Formation of Cathode Fe Nicarbazin-based catalyst (NPC-2000, manufactured by Pajarito) 0.03 g and Ketjen Black 0.02 g were mixed with a solvent (tetrahydrofuran and 1-propyl alcohol in a mass ratio of 1: 1). The mixture was dispersed in 1.5 g by sonication at 25 ° C. for 10 minutes.

  To the obtained mixture, 1.0 g of a 2% by mass anion exchange resin solution (solvent: a mixture of tetrahydrofuran and 1-propyl alcohol at a mass ratio of 1: 1) was added.

  Then, an ink for a cathode was prepared by dispersing with ultrasonic waves at 25 ° C. for 3 minutes.

  The obtained cathode ink was applied by spraying so as to cover the other side of the anion exchange membrane (the surface opposite to the surface on which the anode is formed).

  Then, the cathode was formed by drying at 25 degreeC.

The amount of catalyst supported on the cathode was 1.0 mg / cm ² .
(1-3) Formation of porous layer To 0.2 g of Fe nicarbazine-based catalyst (NPC-2000, manufactured by Pajarito), 1.5 g of solvent (water + 1-propanol (1: 3 mass ratio)), 40 mass% PTFE 0.12 g of (polytetrafluoroethylene) solution and 0.12 g of 40 mass% FEP (tetrafluoroethylene / hexafluoropropylene copolymer) solution were added and dispersed at 25 ° C. for 60 minutes by ultrasonic treatment.

  The obtained ink was applied by a doctor blade so as to cover one surface of the carbon sheet (air diffusion sheet) of the conductive porous body.

  Thereafter, the coated ink was dried at 25 ° C., and then heat-treated in a nitrogen atmosphere at 100 ° C. for 60 minutes, 260 ° C. for 60 minutes, and 360 ° C. for 60 minutes.

After the heat treatment, a porous layer was formed on the carbon sheet (air diffusion sheet) by cold pressing at 5 MPa. The catalyst loading of the porous layer was 5.0 mg / cm ² .
(1-4) Assembly of fuel cell A carbon sheet (fuel diffusion sheet) is joined to the anode of the membrane electrode assembly in which the anode and cathode are formed, and a carbon sheet with a porous layer (air diffusion sheet) is attached to the cathode. Joined.

A fuel cell was assembled by attaching a sealing material to the obtained joined body and sandwiching it between an anode side separator and a cathode side separator.
<Comparative Example 3>
In the formation of the porous layer (see (1-3) above), a fuel cell was obtained in the same manner as in Example 3 except that ketjen black was used instead of the Fe nicarbazine-based catalyst.
(2) Performance Evaluation (2-1) Measurement of Open Circuit Voltage For the fuel cells obtained in Example 3 and Comparative Example 3, the open circuit voltage was measured with an electronic load (manufactured by Scribner).

At the time of measurement, a hydrated hydrazine 1 mol / dm ³ · 1N potassium hydroxide aqueous solution was supplied to the anode at a rate of 1.2 mL / min, and saturated humidified air at 25 ° C. was supplied to the cathode at a rate of 0.1 L / min. Feeded at speed. The cell operating temperature of the fuel cell was 60 ° C. The results are shown in FIG.
(2-2) Measurement of the amount of hydrogen peroxide generated Collect the waste liquid on the cathode side when measuring the open circuit voltage, and measure the amount of hydrogen peroxide generated in the waste liquid using a hydrogen peroxide test paper (manufactured by Hishie Chemical Co., Ltd.). It was measured. The results are shown in FIG.

DESCRIPTION OF SYMBOLS 1 Fuel cell 2 Membrane electrode assembly 5 Anode side separator 6 Cathode side separator 7 Electrolyte membrane 8 Anode 9 Cathode 11 Porous layer

Claims (2)

  Hydrogen peroxide decomposition, comprising a fired body of a raw material complex containing at least one of an Fe complex in which a ligand is coordinated with iron and an Mn complex in which a ligand is coordinated with manganese catalyst. A membrane electrode assembly having an electrolyte membrane, an anode formed on one surface of the electrolyte membrane, and a cathode formed on the other surface of the electrolyte membrane;
An anode separator disposed on one side of the membrane electrode assembly;
A cathode separator disposed on the other side of the membrane electrode assembly;
A porous layer disposed between the cathode and the cathode separator,
The porous layer includes a fired body of a raw material complex containing at least one of an Fe complex in which a ligand is coordinated to iron and an Mn complex in which a ligand is coordinated to manganese. A fuel cell.

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